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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><FONT STYLE="font-size: 8pt"><B>As filed
with the Securities and Exchange Commission on March 27, 2019</B></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right"><FONT STYLE="font-size: 8pt">Registration
No. 333-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</FONT></P>



<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left"><A HREF="#toc"><FONT STYLE="font-size: 7pt">Table of Contents</FONT></A></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>UNITED STATES</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>SECURITIES AND EXCHANGE COMMISSION</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>WASHINGTON, D.C. 20549</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>____________________</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 6pt 0; text-align: center"><B>FORM S-8</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>REGISTRATION STATEMENT</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>UNDER</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 6pt; text-align: center"><B>THE SECURITIES ACT OF 1933</B></P>

<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>PHIO PHARMACEUTICALS CORP. </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 6pt; text-align: center">(Exact Name of Registrant as Specified
in the Charter)</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 44%; font: 10pt Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Delaware</B></FONT></TD>
    <TD STYLE="width: 56%; font: 10pt Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>45-3215903</B></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font: 10pt Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">(State or other jurisdiction of incorporation or organization)</FONT></TD>
    <TD STYLE="font: 10pt Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">(I.R.S. Employer Identification No.)</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 44%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>257 Simarano Drive, Suite 101</B></FONT><BR>
<FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Marlborough, MA</B></FONT></TD>
    <TD STYLE="width: 56%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>01752</B></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 8pt">(Address
    of principal executive offices)</FONT></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 8pt">(Zip
    Code)</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 14pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Non-Plan Stock Compensation Election
and Terms and Conditions</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 6pt; text-align: center"><FONT STYLE="font-size: 8pt"><I>(Full
title of the plan)</I></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><FONT STYLE="font-size: 8pt"><B>Gerrit
Dispersyn, Dr. Med. Sc. </B></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>President &amp; Chief Executive Officer</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Phio Pharmaceuticals Corp.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>257 Simarano Drive, Suite 101 </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Marlborough, Massachusetts 01752 </B><BR>
<B>(508) 767-3861</B><BR>
<FONT STYLE="font-size: 8pt"><I>(Name, address and telephone number, including area code, of agent for service)</I></FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 6pt 0; text-align: center"><B>Copies to:</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Ryan A. Murr</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Gibson, Dunn &amp; Crutcher LLP</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>555 Mission Street, Suite 3000</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>San Francisco, CA 94105</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Telephone: (415)393-8373</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Facsimile: (415) 374 - 8430</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 6pt 0">Indicate by check mark whether the registrant is a large accelerated
filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions
of &ldquo;large accelerated filer,&rdquo; &ldquo;accelerated filer,&rdquo; &ldquo;smaller reporting company&rdquo; and &ldquo;emerging
growth company&rdquo; in Rule 12b-2 of the Exchange Act.</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 23%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Large accelerated filer &#9744;</FONT></TD>
    <TD STYLE="width: 49%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line">&nbsp;</TD>
    <TD STYLE="width: 28%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Accelerated filer &#9744;</FONT></TD></TR>
<TR>
    <TD STYLE="vertical-align: bottom; font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Non-accelerated
filer &#9746;</FONT></TD>
    <TD STYLE="vertical-align: bottom; font-family: Courier New, Courier, Monospace; layout-grid-mode: line">&nbsp;</TD>
    <TD STYLE="vertical-align: top; font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Smaller
reporting company &#9746;</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line">&nbsp;</TD>
    <TD>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Emerging growth company &#9744;</P></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 6pt 0">If an emerging growth company, indicate by check mark if the
registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards
provided pursuant to Section 7(a)(2)(B) of the Securities Act. &#9744;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>CALCULATION OF REGISTRATION FEE</B></P>

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<TR STYLE="vertical-align: top">
    <TD STYLE="width: 32%; border-top: Black 2.25pt double; border-left: Black 2.25pt double; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 8pt">Title
    of Securities to be Registered</FONT></TD>
    <TD STYLE="width: 13%; border-top: Black 2.25pt double; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 8pt">Amount
    to be Registered (1)</FONT></TD>
    <TD STYLE="width: 21%; border-top: Black 2.25pt double; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 8pt">Proposed
    Maximum Offering Price Per Share (3)</FONT></TD>
    <TD STYLE="width: 19%; border-top: Black 2.25pt double; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 8pt">Proposed
    Maximum Aggregate Offering Price (3)</FONT></TD>
    <TD STYLE="width: 15%; border-top: Black 2.25pt double; border-right: Black 2.25pt double; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 8pt">Amount
    of Registration Fee</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-top: Black 1pt solid; border-bottom: Black 1pt solid; border-left: Black 2.25pt double; font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 9pt">Common
    Stock, par value $0.0001 per share (&ldquo;Common Stock&rdquo;)</FONT></TD>
    <TD STYLE="border-top: Black 1pt solid; border-bottom: Black 1pt solid; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 9pt">446,334(2)
    </FONT></TD>
    <TD STYLE="border-top: Black 1pt solid; border-bottom: Black 1pt solid; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 9pt">$0.4302</FONT></TD>
    <TD STYLE="border-top: Black 1pt solid; border-bottom: Black 1pt solid; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 9pt">$191,990.56</FONT></TD>
    <TD STYLE="border-top: Black 1pt solid; border-right: Black 2.25pt double; border-bottom: Black 1pt solid; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 9pt">$23.27</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

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<TD STYLE="width: 0.25in"><FONT STYLE="font-size: 9pt">(1)</FONT></TD><TD STYLE="text-align: left"><FONT STYLE="font-size: 9pt">Pursuant to Rule 416(a) under the
                                  Securities Act of 1933, as amended (the &ldquo;Securities Act&rdquo;), this Registration Statement
                                  also covers such additional shares of Common Stock as may be issued in respect of the securities
                                  registered by this Registration Statement as a result of any stock dividend, stock split, recapitalization
                                  or other similar transaction.</FONT></TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.25in; text-align: justify; text-indent: -0.25in"><FONT STYLE="font-size: 8pt">&nbsp;</FONT></P>

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<TD STYLE="width: 0.25in"><FONT STYLE="font-size: 9pt">(2)</FONT></TD><TD STYLE="text-align: left"><FONT STYLE="font-size: 9pt">This Registration Statement covers
                                  the resale of 446,334 shares of Common Stock that have been previously issued to Dr. Geert Cauwenbergh
                                  (the &ldquo;Selling Stockholder&rdquo;) in the form of restricted shares subject to time-based
                                  vesting conditions. Such shares were granted to the Selling Stockholder by Phio Pharmaceuticals
                                  Corp. (the &ldquo;Company&rdquo;) following the Selling Stockholder&rsquo;s election to receive
                                  such shares in lieu of cash-based compensation for his services to the Company as its President
                                  and Chief Executive Officer. The Selling Stockholder&rsquo;s election is memorialized in the
                                  Non-Stock Plan Compensation Election and Terms and Conditions, dated August 31, 2018, as amended
                                  by Amendment No. 1 to the Non-Plan Stock Compensation Election and Terms and Conditions, dated
                                  December 19, 2018, and Amendment No. 2 to the Non-Plan Stock Compensation Election and Terms
                                  and Conditions, dated February 14, 2019.</FONT></TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.25in; text-align: left; text-indent: -0.25in"><FONT STYLE="font-size: 8pt">&nbsp;</FONT></P>

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.25in"><FONT STYLE="font-size: 9pt">(3)</FONT></TD><TD STYLE="text-align: left"><FONT STYLE="font-size: 9pt">Calculated pursuant to Rule 457(h)
                                  of the Securities Act solely for the purpose of computing the amount of the registration fee,
                                  on the basis of the average of the high and low prices of the Common Stock quoted on The Nasdaq
                                  Capital Market on March 20, 2019.</FONT></TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.25in; text-align: left"></P>



<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>EXPLANATORY NOTE</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Phio Pharmaceuticals Corp. (the &ldquo;Company&rdquo;
or the &ldquo;Registrant&rdquo;) has prepared this Registration Statement on Form S-8 (the &ldquo;Registration Statement&rdquo;)
in accordance with the requirements of Form S-8 under the Securities Act of 1933, as amended (the &ldquo;Securities Act&rdquo;),
to register the resale of up to 446,334 shares (the &ldquo;Shares&rdquo;) of its Common Stock, par value $0.0001 per share, issued
prior to the filing of this Registration Statement and held by the Selling Stockholder named herein in connection with such Selling
Stockholder&rsquo;s provision of services to the Registrant.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">This Registration Statement contains two
parts. The first part contains a &ldquo;reoffer&rdquo; prospectus prepared in accordance with Part I of Form S-3 (in accordance
with Instruction C of the General Instructions to Form S-8). The reoffer prospectus permits reoffers and resales of those shares
referred to above that constitute &ldquo;restricted securities,&rdquo; within the meaning of Form S-8, by the Selling Stockholder
named herein. The second part contains information required to be set forth in the Registration Statement pursuant to Part II of
Form S-8. The Company will provide, without charge, to any person, upon written or oral request of such person, a copy of each
document incorporated by reference in Item 3 of Part II of this Registration Statement (which documents are also incorporated by
reference in the reoffer prospectus as set forth in Form S-8), other than exhibits to such documents that are not specifically
incorporated by reference.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>PROSPECTUS</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>446,334 SHARES</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>PHIO PHARMACEUTICALS CORP. </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>COMMON STOCK</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">This prospectus relates to 446,334 shares
(the &ldquo;Shares&rdquo;) of common stock, par value $0.0001 per share (the &ldquo;Common Stock&rdquo;) of Phio Pharmaceuticals
Corp. (the &ldquo;Company&rdquo;) which may be offered from time to time by the Selling Stockholder of the Company, named herein,
for such Selling Stockholder&rsquo;s own account. We will not receive any proceeds from any sale of Common Stock offered pursuant
to this prospectus.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The Selling Stockholder may offer and sell
the Shares at various times and in various types of transactions, including sales in the open market, sales in negotiated transactions
and sales by a combination of these methods. The Shares may be sold at the market price of the Common Stock at the time of a sale,
at prices relating to the market price over a period of time, or at prices negotiated with the buyers of shares. The Shares may
be sold through underwriters or dealers which the Selling Stockholder may select. If underwriters or dealers are used to sell the
Shares, we will name them and describe their compensation in a prospectus supplement. For a description of the various methods
by which the Selling Stockholder may offer and sell the Shares described in this prospectus, see the section entitled &ldquo;Plan
of Distribution.&rdquo;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Our Common Stock is quoted on the Nasdaq
Capital Market under the symbol &ldquo;PHIO.&rdquo; On March 26, 2019, the closing price of our Common stock was $0.425.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Investing in our Common Stock
involves risks. See the sections entitled &ldquo;<A HREF="#a2">Disclosure Regarding Forward-Looking Statements</A>&rdquo; on
page 2 and &ldquo;<A HREF="#a3">Risk Factors</A>&rdquo; on page 2  of this prospectus to read about factors to consider in
connection with purchasing our Common Stock.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Neither the Securities and Exchange Commission
nor any state securities commission has approved or disapproved these securities, or determined if this prospectus is truthful
or complete. Any representation to the contrary is a criminal offense.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0.5in">The date of this prospectus
is March 27, 2019</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><A NAME="toc"></A><B>TABLE OF CONTENTS</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: right"><B>Page</B></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 88%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a1"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">THE COMPANY</FONT></A></TD>
    <TD STYLE="width: 12%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">1</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a2"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">2</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a3"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">RISK FACTORS</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">2</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a4"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">USE OF PROCEEDS</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">2</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a5"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">SELLING STOCKHOLDER</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">2</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a6"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">PLAN OF DISTRIBUTION</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">3</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a7"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">LEGAL MATTERS</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">3</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a9"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">EXPERTS</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">3</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a10"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">PART I</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a10"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">4</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a12"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">PART II</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">&nbsp;</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a10"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">INFORMATION REQUIRED IN THE REGISTRATION STATEMENT</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">4</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><A HREF="#a20"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">EXHIBIT INDEX</FONT></A></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">8</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="#a21">SIGNATURES</A></FONT></TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: right"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">9</FONT></TD></TR>
</TABLE>
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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: left">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: left">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: left"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt; text-align: left">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a1"></A>THE COMPANY</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><I>Unless otherwise noted, (1) the term &ldquo;Phio&rdquo; refers
to Phio Pharmaceuticals Corp. and our subsidiary, MirImmune, LLC and (2) the terms &ldquo;Company,&rdquo; &ldquo;we,&rdquo; &ldquo;us&rdquo;
and &ldquo;our&rdquo; refer to the ongoing business operations of Phio and MirImmune, LLC, whether conducted through Phio or MirImmune,
LLC.</I></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Phio Pharmaceuticals Corp. is a biotechnology
company developing the next generation of immuno-oncology therapeutics based on our self-delivering RNAi (&ldquo;<B>sd-rxRNA<SUP>&reg;</SUP></B>&rdquo;)
therapeutic platform. The Company&rsquo;s efforts are focused on developing sd-rxRNA therapeutic compounds to be used in the context
of adoptive cell transfer by targeting checkpoints or other gene targets, or to be used in immunotherapy following intra-tumoral
injections. We aim to maximize the power of our sd-rxRNA therapeutic compounds by weaponizing therapeutic immune effector cells
to attack cancer, and to make tumors more susceptible to such attacks, and ultimately provide patients battling cancers with a
powerful new treatment option that goes beyond current treatment modalities.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in"><FONT STYLE="background-color: white">In
January 2017, the Company entered into a Stock Purchase Agreement pursuant to which it acquired all of the issued and outstanding
shares of capital stock of MirImmune Inc. (&ldquo;<B>MirImmune</B>&rdquo;) for an aggregate of 275,036 shares of common stock of
the Company and 1,118,224 shares of the Company&rsquo;s Series C Convertible Preferred Stock. With the approval of the Company&rsquo;s
stockholders at the 2017 Annual Meeting of Stockholders, every ten shares of the Series C Convertible Preferred Stock issued and
outstanding were automatically converted into one share of common stock.</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in"><FONT STYLE="background-color: white">Prior
to the Company&rsquo;s acquisition of MirImmune, our principal activities consisted of the preclinical and clinical development
of the Company&rsquo;s sd-rxRNA compounds and topical immunotherapy agent in the areas of dermatology and ophthalmology. In January
2018, after a thorough review of its business operations, development programs and financial resources, the Company made a strategic
decision to focus its efforts solely on immuno-oncology to accelerate growth and support a potential return on investment for its
stockholders. In connection with this decision, the Company completed all open clinical trials in dermatology and ophthalmology
with RXI-109, our first sd-rxRNA clinical candidate, and Samcyprone<SUP>&reg;</SUP>, and reported out on the results of those clinical
studies in 2018. The Company intends to seek a partner and/or out-licensee for its dermatology program and its ophthalmology program
to continue with their development. The Company&rsquo;s current business strategy solely focuses on the development of immuno-oncology
therapeutics utilizing our proprietary sd-rxRNA technology.</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in"><FONT STYLE="background-color: white">On
November 19, 2018, the Company changed its name from RXi Pharmaceuticals Corporation to Phio Pharmaceuticals Corp., which reflects
the Company&rsquo;s transition from a platform company to one that is fully committed to develop groundbreaking immuno-oncology
therapeutics. </FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Our development efforts are based on our
broadly patented sd-rxRNA technology platform. Our sd-rxRNA compounds do not require a delivery vehicle to penetrate into tissues
and cells and are designed to &ldquo;silence,&rdquo; or down-regulate, the expression of a specific gene that may be over-expressed
in a disease condition. We believe that our sd-rxRNA platform uniquely positions the Company in the field of immuno-oncology because
of this and for the following reasons:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>



<TABLE CELLPADDING="0" CELLSPACING="0" BORDER="0" STYLE="width: 100%; margin-top: 0pt; margin-bottom: 0pt; font: 10pt Times New Roman, Times, Serif">                                                                                                                                                     <TR STYLE="vertical-align: top">
<TD>&nbsp;</TD><TD><FONT STYLE="font-family: Symbol">&middot;</FONT></TD><TD>Our sd-rxRNA compounds not require facilitated delivery (mechanical or formulation);</TD></TR>
<TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in"><FONT STYLE="font-family: Symbol">&middot;</FONT></TD><TD>Can target multiple genes (i.e. multiple immunosuppression pathways) in a single therapeutic entity;</TD></TR></TABLE>

<TABLE CELLPADDING="0" CELLSPACING="0" BORDER="0" STYLE="width: 100%; margin-top: 0pt; margin-bottom: 0pt; font: 10pt Times New Roman, Times, Serif"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in"><FONT STYLE="font-family: Symbol">&middot;</FONT></TD><TD>Demonstrate efficient uptake of sd-rxRNA to immune cells;</TD></TR></TABLE>

<TABLE CELLPADDING="0" CELLSPACING="0" BORDER="0" STYLE="width: 100%; margin-top: 0pt; margin-bottom: 0pt; font: 10pt Times New Roman, Times, Serif"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in"><FONT STYLE="font-family: Symbol">&middot;</FONT></TD><TD>Silencing by sd-rxRNA has been shown to have a sustained, or long-term, effect <I>in vivo</I>;</TD></TR></TABLE>

<TABLE CELLPADDING="0" CELLSPACING="0" BORDER="0" STYLE="width: 100%; margin-top: 0pt; margin-bottom: 0pt; font: 10pt Times New Roman, Times, Serif"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in"><FONT STYLE="font-family: Symbol">&middot;</FONT></TD><TD>Favorable clinical safety profile of sd-rxRNA with local administration; and</TD></TR></TABLE>

<TABLE CELLPADDING="0" CELLSPACING="0" BORDER="0" STYLE="width: 100%; margin-top: 0pt; margin-bottom: 0pt; font: 10pt Times New Roman, Times, Serif"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in"><FONT STYLE="font-family: Symbol">&middot;</FONT></TD><TD>Can be readily manufactured under current good manufacturing practices.</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in"><FONT STYLE="font-size: 10pt">We are incorporated
in Delaware, and our principal executive offices are located at 257 Simarano Drive, Suite 101, Marlborough, Massachusetts 01752,
and our telephone number is (508) 767-3861. Additional information regarding the Company is set forth in the Company&rsquo;s Annual
Report on Form 10-K for the fiscal year ended December 31, 2018 (which is incorporated herein by reference). </FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a2"></A>DISCLOSURE REGARDING
FORWARD-LOOKING STATEMENTS</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">This report contains forward-looking statements
within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words
such as &ldquo;intends,&rdquo; &ldquo;believes,&rdquo; &ldquo;anticipates,&rdquo; &ldquo;indicates,&rdquo; &ldquo;plans,&rdquo;
&ldquo;expects,&rdquo; &ldquo;suggests,&rdquo; &ldquo;may,&rdquo; &ldquo;should,&rdquo; &ldquo;potential,&rdquo; &ldquo;designed
to,&rdquo; &ldquo;will&rdquo; and similar references, although not all forward-looking statements contain these words. Forward-looking
statements are neither historical facts nor assurances of future performance. These statements are based only on our current beliefs,
expectations and assumptions regarding the future of our business, future plans and strategies, projections, anticipated events
and trends, the economy and other future conditions. Because forward-looking statements relate to the future, they are subject
to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our
control. Our actual results and financial condition may differ materially from those indicated in the forward-looking statements
as a result of a number of important factors, including those identified in this Registration Statement on Form S-8 under the heading
&ldquo;Risk Factors&rdquo; and in other filings the Company periodically makes with the Securities and Exchange Commission. Therefore,
you should not rely on any of these forward-looking statements. Forward-looking statements contained in this Registration Statement
on Form S-8 speak as of the date hereof and the Company does not undertake to update any of these forward-looking statements to
reflect a change in its views or events or circumstances that occur after the date of this report.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a3"></A>RISK FACTORS</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Investing in our securities involves a high
degree of risk.&nbsp; You should carefully consider the risks and uncertainties described in the documents incorporated herein
by reference, as well as other information we include or incorporate by reference.&nbsp; Our business, financial condition or results
of operations could be materially adversely affected by the materialization of any of these risks. The trading price of our
securities could decline due to the materialization of any of these risks, and you may lose all or part of your investment.&nbsp;
This prospectus and the documents incorporated herein by reference also contain forward-looking statements that involve risks and
uncertainties.&nbsp; Actual results could differ materially from those anticipated in these forward-looking statements as a result
of certain factors, including the risks described under the headings &ldquo;Risk Factors&rdquo; in the documents incorporated herein
by reference, including in our Annual Report on Form 10-K for the year ended December 31, 2018 and any risk factors set forth in
our other filings with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including our Quarterly Reports
on Form 10-Q and our Current Reports on Form 8-K, before making an investment decision.</P>

<P STYLE="font: 10pt Courier; margin: 0pt 0 0pt 0.25in; text-indent: -0.25in">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a4"></A>USE OF PROCEEDS</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The proceeds from the sale of the shares
offered pursuant to this prospectus are solely for the account of the Selling Stockholder. We will not receive any of the proceeds
from any sale of shares by the Selling Stockholder.</P>

<P STYLE="font: 10pt Courier; margin: 0pt 0; text-indent: 154.65pt">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a5"></A>SELLING STOCKHOLDER</P>

<P STYLE="font: 10pt Courier; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The Common Stock being registered by this
prospectus consists of 446,334 shares that are currently held by Dr. Geert Cauwenbergh, the Selling Stockholder, and were issued
to the Selling Stockholder pursuant to a written compensation contract by and between the Company and the Selling Stockholder in
connection with his service as the President and Chief Executive Officer of the Company.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">We are registering these shares to permit
the Selling Stockholder to resell these shares when he deems appropriate. The Selling Stockholder may resell all, a portion, or
none of the shares, at any time and from time to time. The Selling Stockholder may also sell, transfer or otherwise dispose of
some or all of the shares in transactions exempt from the registration requirements of the Securities Act. We do not know when
or in what amounts the Selling Stockholders may offer the shares of common stock for sale under this prospectus.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The Selling Stockholder holds less than
5% of the Company&rsquo;s outstanding common stock and is an affiliate of the Company. The Selling Stockholder has served as the
President and Chief Executive Officer of the Company during the last three years. The following table sets forth: (i) the number
and percentage of shares of our common stock that the Selling Stockholder beneficially owned as of March 1, 2019 prior to the offering
for resale of the shares under this prospectus; (ii) the number of shares of our Common Stock that may be offered for resale for
the account of the Selling Stockholder under this prospectus; and (iii) the number and percentage of shares of our Common Stock
to be beneficially owned by the Selling Stockholder after the offering of the resale shares (assuming all of the offered resale
shares are sold by such Selling Stockholder).</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="border: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Selling Stockholder</B></FONT></TD>
    <TD COLSPAN="2" STYLE="border-top: Black 1pt solid; border-right: Black 1pt solid; border-bottom: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Number of Shares Beneficially Owned Prior to Offering</B></FONT></TD>
    <TD ROWSPAN="2" STYLE="border-top: Black 1pt solid; border-right: Black 1pt solid; border-bottom: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Number of Shared Being Offered</B></FONT></TD>
    <TD COLSPAN="2" STYLE="border-top: Black 1pt solid; border-right: Black 1pt solid; border-bottom: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Number of Shares Beneficially Owned After the Offering</B></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-right: Black 1pt solid; border-bottom: Black 1pt solid; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line">&nbsp;</TD>
    <TD STYLE="border-right: Black 1pt solid; border-bottom: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Number</FONT></TD>
    <TD STYLE="border-right: Black 1pt solid; border-bottom: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Percent</FONT></TD>
    <TD STYLE="border-right: Black 1pt solid; border-bottom: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Number</FONT></TD>
    <TD STYLE="border-right: Black 1pt solid; border-bottom: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Percent</FONT></TD></TR>
<TR STYLE="vertical-align: top; background-color: rgb(238,238,238)">
    <TD STYLE="width: 24%; border-right: Black 1pt solid; border-bottom: Black 1pt solid; border-left: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Dr. Geert Cauwenbergh</FONT></TD>
    <TD STYLE="width: 12%; border-bottom: Black 1pt solid; border-right: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">502,862</FONT></TD>
    <TD STYLE="width: 16%; border-bottom: Black 1pt solid; border-right: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">2.41%</FONT></TD>
    <TD STYLE="width: 14%; border-bottom: Black 1pt solid; border-right: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">446,334</FONT></TD>
    <TD STYLE="width: 18%; border-bottom: Black 1pt solid; border-right: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">56,528</FONT></TD>
    <TD STYLE="width: 16%; border-bottom: Black 1pt solid; border-right: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">*</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left; text-indent: 0in"><FONT STYLE="font-weight: normal">*
Less than 1%</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left; text-indent: 0in"><FONT STYLE="font-weight: normal">&nbsp;</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left; text-indent: 0in"><FONT STYLE="font-weight: normal">&nbsp;</FONT></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left; text-indent: 0in"><FONT STYLE="font-weight: normal">&nbsp;</FONT></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left"><FONT STYLE="font-weight: normal"></FONT>&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left"></P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a6"></A>PLAN OF DISTRIBUTION</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The purpose of this reoffer prospectus is
to allow the Selling Stockholder to offer for sale and sell all or a portion of his shares acquired in connection with the provision
of services to the Company. The Selling Stockholder may sell the shares of common stock registered pursuant to this reoffer prospectus
directly to purchasers or through broker-dealers or agents, who may receive compensation in the form of discounts, concessions
or commissions from the Selling Stockholder or the purchasers. These commissions as to any particular broker-dealer or agent may
be in excess of those customary in the types of transactions involved. Neither we nor the Selling Stockholder can presently estimate
the amount of this compensation.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The common stock offered under this reoffer
prospectus may be sold in one or more transactions at fixed prices, at prevailing market prices at the time of sale, at prices
related to the prevailing market prices, at varying prices determined at the time of sale, or at negotiated prices. These sales
may be effected in transactions, which may involve block transactions, on any national securities exchange on which the Company&rsquo;s
common stock may be then-listed.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The aggregate proceeds to the Selling Stockholder
from the sale of the shares will be the purchase price of the common stock less discounts and commissions, if any. The Selling
Stockholder reserves the right to accept and, together with his agents from time to time, to reject, in whole or in part, any proposed
purchase of the shares to be made directly or through agents. We will not receive any of the proceeds from a sale of the shares
by the Selling Stockholder.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The Selling Stockholder and any broker-dealers
or agents that participate in the sale of the shares may be deemed to be &ldquo;underwriters&rdquo; under the Securities Act. Any
discounts, commissions, concessions or profit they earn on any resale of the shares may be underwriting discounts and commissions
under the Securities Act. If the Selling Stockholder is an &ldquo;underwriter&rdquo; under the Securities Act, the Selling Stockholder
will be subject to the prospectus delivery requirements of the Securities Act.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The shares to be offered or resold by means
of this reoffer prospectus by the Selling Stockholder may not exceed, during any three-month period, the amount specified in Rule
144(e) under the Securities Act. In addition, any securities covered by this reoffer prospectus which qualify for sale pursuant
to Rule 144 of the Securities Act may be sold under Rule 144 of the Securities Act rather than pursuant to this reoffer prospectus.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">There can be no assurance that the Selling
Stockholder will sell any or all of the securities offered by them hereby.</P>

<P STYLE="font: 10pt Courier; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a7"></A>LEGAL MATTERS</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">We are being represented by Gibson,
Dunn &amp; Crutcher LLP, who will pass upon the validity of the shares being offered by this prospectus.</P>

<P STYLE="font: 10pt Courier; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a9"></A>EXPERTS</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in; color: fuchsia">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The consolidated financial
statements as of December 31, 2018 and 2017 and for each of the two years in the period ended December 31, 2018 incorporated by
reference in this Prospectus have been so incorporated in reliance on the report of BDO USA, LLP, an independent registered public
accounting firm, incorporated herein by reference, given on the authority of said firm as experts in auditing and accounting.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B></B></P>

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<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><A NAME="a10"></A><B>PART I</B></P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in">INFORMATION REQUIRED
IN THE SECTION 10(a) PROSPECTUS</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><A NAME="a11"></A><B>Item 1.&#9;Plan Information</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Information required by Part I to be contained
in the Section 10(a) prospectus is omitted from this Registration Statement in accordance with Rule 428 under the Securities Act
of 1933, as amended (the &ldquo;Securities Act&rdquo;), and the Note to Part I of Form S-8.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-indent: -0.5in"><B>&nbsp;</B></P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B><A NAME="a12"></A>PART II</B></P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in">INFORMATION REQUIRED
IN THE REGISTRATION STATEMENT</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-indent: -0.5in"><A NAME="a13"></A><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>Item 3.&#9;Incorporation of Documents by Reference.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">The following documents filed by Phio Pharmaceuticals
Corp. (the &ldquo;Registrant&rdquo;) with the Securities and Exchange Commission are incorporated herein by reference:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.5in">(1)</TD><TD>the Registrant&rsquo;s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on March 27, 2019;</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-indent: -0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-indent: -0.5in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.5in">(2)</TD><TD>the Registrant&rsquo;s Current Reports on Form 8-K, filed with the SEC on January 28, 2019 and February 15, 2019; and</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-indent: -0.5in">&nbsp;</P>

<TABLE CELLPADDING="0" CELLSPACING="0" WIDTH="100%" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; margin-bottom: 0pt"><TR STYLE="vertical-align: top">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.5in">(3)</TD><TD>the description of the Registrant&rsquo;s Common Stock, par value $0.0001 per share, which is contained in the Registrant&rsquo;s
registration statement on Form 8-A filed with the SEC under Section 12 of the Securities Exchange Act of 1934, as amended (the
&ldquo;Exchange Act&rdquo;), on February 7, 2014, including any amendments or reports filed for the purpose of updating such description.</TD></TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 0.5in; text-indent: -0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">All documents subsequently filed by the
Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing of a post-effective amendment
to this Registration Statement that indicates that all securities offered have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated herein by reference from the date of filing of such documents. Any statement
contained herein or in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified
or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any subsequently
filed document which also is incorporated or is deemed to be incorporated by reference herein modifies or supersedes such earlier
statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute part
of this Registration Statement.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><A NAME="a14"></A><B>Item 4.&#9;Description of Securities.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">Not applicable.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><A NAME="a15"></A><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>Item 5.&#9;Interests of Named Experts
and Counsel.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">Not applicable.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B><A NAME="a16"></A>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>Item 6.&#9;Indemnification of Directors
and Officers.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Section 145 of the Delaware General Corporation
Law (the &ldquo;DGCL&rdquo;) provides that a corporation may indemnify any current or former director, officer or employee or other
individual against expenses, judgments, fines and amounts paid in settlement in connection with civil, criminal, administrative
or investigative actions or proceedings, other than a derivative action by or in the right of the corporation, if the director,
officer, employee or other individual acted in good faith and in a manner he or she reasonably believed to be in or not opposed
to the best interests of the corporation, and, with respect to any criminal action or proceeding, if he or she had no reasonable
cause to believe his or her conduct was unlawful. A similar standard is applicable in the case of derivative actions, except that
indemnification extends only to expenses incurred in connection with the defense or settlement of such actions, and the statute
requires court approval before there can be any indemnification where the person seeking indemnification has been found liable
to the corporation. The statute provides that it is not exclusive of other indemnification that may be granted by a corporation&rsquo;s
by-laws, disinterested director vote, stockholder vote, agreement or otherwise.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Our certificate of incorporation provides
that we will indemnify to the fullest extent authorized or permitted by the DGCL or any other applicable law as now or hereafter
in effect any person made, or threatened to be made, a defendant or witness to any action, suit or proceeding (whether civil, criminal
or otherwise) by reason of the fact that he is or was a director of our corporation or by reason of the fact that such director,
at our request, is or was serving any other corporation, partnership, joint venture, trust, employee benefit plan or other enterprise
in any capacity. Our certificate of incorporation also provides that no amendment or repeal of the certificate of incorporation
will apply to or have any effect on any right to indemnification provided in the certificate of incorporation with respect to any
acts or omissions occurring prior to such amendment or repeal.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">As permitted by the DGCL, our bylaws, as
amended, provide that we will indemnify to the fullest extent authorized or permitted by applicable law as now or hereafter in
effect any person who was or is made, or is threatened to be made, a party or is otherwise involved in any action, suit or proceeding
(whether civil, criminal, administrative or investigative), by reason of the fact that he (or a person for whom he is the legal
representative) is or was a director or officer of our corporation, is or was serving at our request as a director, officer, employee,
member, trustee or agent of another corporation or of a partnership, joint venture, trust, nonprofit entity or other enterprise.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Consequently, no director of the corporation
will be personally liable to the corporation or its stockholders for monetary damages for any breach of fiduciary duty by such
a director as a director. However, notwithstanding the preceding sentence, a director will be liable to the extent provided by
Delaware law (1) for any breach of the director&rsquo;s duty of loyalty to the corporation or its stockholders, (2) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (3) for payments of unlawful
dividends or for unlawful stock repurchases or redemption, or (4) for any transaction from which the director derived an improper
personal benefit.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">We have entered into indemnification agreements
with each of our executive officers and directors. These agreements provide that, subject to limited exceptions and among other
things, we will indemnify each of our executive officers and directors to the fullest extent permitted by law and advance expenses
to each indemnitee in connection with any proceeding in which a right to indemnification is available.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">We also maintain insurance on behalf of
any person who is or was our director, officer, trustee, employee or agent or serving at our request as a director, officer, trustee,
employee or agent of another corporation, partnership, joint venture, trust, non-profit entity or other enterprise against any
liability asserted against the person and incurred by the person in any such capacity, or arising out of his or her status as such.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Insofar as indemnification for liabilities
arising under the Securities Act may be permitted for directors, officers, or persons who control us, we have been informed that,
in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><A NAME="a17"></A><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>Item 7.&#9;Exemption from Registration
Claimed.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Not applicable.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B><A NAME="a18"></A>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>Item 8.&#9;Exhibits.</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">See exhibits listed
under Exhibit Index below.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><A NAME="a19"></A>&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>Item 9.&#9;Undertakings. </B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">(a) The undersigned Registrant hereby undertakes:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 45.8pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 45.8pt">(1) To file, during any period in which
offers or sales are being made, a post-effective amendment to this Registration Statement:</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">(i) To include any prospectus required
by Section 10(a)(3) of the Securities Act;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">(ii) To reflect in the prospectus any facts
or events arising after the effective date of the Registration Statement (or the most recent post-effective amendment thereof)
which, individually or in the aggregate, represent a fundamental change in the information set forth in the Registration Statement.
Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities
offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering
range may be reflected in the form of prospectus filed with the Commission pursuant to Rule&nbsp;424(b) if, in the aggregate, the
changes in volume and price represent no more than 20% change in the maximum aggregate offering price set forth in the &ldquo;Calculation
of Registration Fee&rdquo; table in the effective registration statement; and</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 91.6pt">(iii) To include any material information
with respect to the plan of distribution not previously disclosed in the Registration Statement or any material change to such
information in the Registration Statement;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">p<I>rovided, however, </I>that paragraphs (a)(1)(i) and (a)(1)(ii)
do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports
filed with or furnished to the Commission by the Registrant pursuant to Section 13 or Section&nbsp;15(d) of the Securities Exchange
Act of 1934 that are incorporated by reference in the Registration Statement;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 45.8pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 45.8pt">(2) That, for the purpose of determining
any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating
to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial <I>bona fide</I>
offering thereof; and</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 45.8pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 45.8pt">(3) To remove from registration by means
of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">(b) The undersigned Registrant hereby undertakes that, for purposes
of determining any liability under the Securities Act, each filing of the Registrant&rsquo;s annual report pursuant to Section&nbsp;13(a)
or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan&rsquo;s annual report pursuant
to Section 15(d) of the Exchange Act) that is incorporated by reference in the Registration Statement shall be deemed to be a new
registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed
to be the initial <I>bona fide</I> offering thereof.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">(c) Insofar as indemnification for liabilities arising under
the Securities Act may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing
provisions, or otherwise, the Registrant has been advised that in the opinion of the Commission such indemnification is against
public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or
controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel
the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such
issue.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"><B></B></P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a20"></A>EXHIBIT INDEX</P>

<P STYLE="font: 10pt Courier; margin: 0pt 0; text-align: justify; text-indent: 0.5in">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="font: 10pt Times New Roman, Times, Serif; width: 100%; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 16%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: left; border-bottom: Black 0.75pt solid"><B>Exhibit
        No.</B></P></TD>
    <TD STYLE="width: 84%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; border-bottom: Black 0.75pt solid"><B>Description</B></P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">4.1</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="http://www.sec.gov/Archives/edgar/data/1533040/000168316818003505/phio_ex0302.htm" STYLE="-sec-extract: exhibit">Amended and Restated Certificate of Incorporation of the Company</A> (incorporated by reference to Exhibit 3.2 of the Company&rsquo;s Current Report on Form 8-K filed on November 19, 2018)</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">4.2</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="http://www.sec.gov/Archives/edgar/data/1533040/000168316818003505/phio_ex0303.htm" STYLE="-sec-extract: exhibit">Amended and Restated Bylaws of the Company</A> (incorporated by reference to Exhibit 3.3 of the Company&rsquo;s Current Report on Form 8-K filed on November 19, 2018)</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">5.1</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="phio_s8-ex0501.htm">Opinion of counsel</A>*</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">10.1</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="http://www.sec.gov/Archives/edgar/data/1533040/000168316818002589/rxi_8k-ex1001.htm" STYLE="-sec-extract: exhibit">Non-Stock Plan Compensation Election and Terms and Conditions, dated August 31, 2018</A> (incorporated by reference to Exhibit 10.1 of the Company&rsquo;s Current Report on Form 8-K filed on September 4, 2018)</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">10.2</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="http://www.sec.gov/Archives/edgar/data/1533040/000168316818003773/phio_8k-ex1001.htm" STYLE="-sec-extract: exhibit">Amendment No. 1 to the Non-Plan Stock Compensation Election and Terms and Conditions, dated December 19, 2018</A> (incorporated by reference to Exhibit 10.1 of the Company&rsquo;s Current Report on Form 8-K filed on December 21, 2018)</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">10.3</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="http://www.sec.gov/Archives/edgar/data/1533040/000168316819000423/phio_8k-ex1001.htm" STYLE="-sec-extract: exhibit">Amendment No. 2 to the Non-Plan Stock Compensation Election and Terms and Conditions, dated February 14, 2019</A> (incorporated by reference to Exhibit 10.1 of the Company&rsquo;s Current Report on Form 8-K filed on February 15, 2019)</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">23.1</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="phio_s8-ex2301.htm">Consent of Independent Registered Public Accounting Firm</A> *</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">23.2</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Consent of counsel (included in Exhibit 5.1)*</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">24</FONT></TD>
    <TD STYLE="text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><A HREF="#poa">Power of Attorney</A> (included on signature page)*</FONT></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">* Filed herewith</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify"></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: bold 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center; text-indent: 0in"><A NAME="a21"></A>SIGNATURES</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Pursuant to the requirements of the Securities
Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all the requirements
for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in Marlborough, Massachusetts, on March 27, 2019.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; text-align: center; margin-bottom: 0pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; text-align: left; margin-bottom: 0pt"></P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 50%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: justify">&nbsp;</TD>
    <TD STYLE="width: 50%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>PHIO PHARMACEUTICS CORP.</B></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: justify">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: justify">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: justify">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: justify"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">By: <U>/s/Gerrit Dispersyn&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</U></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Gerrit Dispersyn, Dr. Med. Sc.</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">President
and Chief Executive Officer</FONT></TD></TR>
</TABLE>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; text-align: left; margin-bottom: 0pt"></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; text-align: center; margin-bottom: 0pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; text-align: center; margin-bottom: 0pt">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0pt; text-align: center; margin-bottom: 0pt"><A NAME="poa"></A><B>POWER OF ATTORNEY</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>&nbsp;</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">KNOW ALL PERSONS BY THESE PRESENTS, that
each person whose signature appears below constitutes and appoints Gerrit Dispersyn, Dr. Med. Sc. as attorney-in-fact and agent,
with full power of substitution and resubstitution, in any and all capacities, to sign any and all amendments (including post-effective
amendments) to this registration statement, and to file the same, with all exhibits thereto and other documents in connection therewith,
with the Securities and Exchange Commission, granting unto said attorney-in-fact and agent, with full power to act alone, full
power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith,
as fully for all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorney-in-fact
and agent, or his substitute or substitutes, may do or cause to be done by virtue thereof.</P>

<P STYLE="font: 10pt Courier; margin: 0pt 0">&nbsp;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Pursuant to the requirements of the Securities Act of 1933,
this registration statement has been signed by the following persons in the capacities and on the dates indicated.&#9;</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify">&nbsp;</P>

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 35%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Signature</B></FONT></TD>
    <TD STYLE="width: 48%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Title</B></FONT></TD>
    <TD STYLE="width: 17%; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt"><B>Date</B></FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-bottom: Black 1pt solid; font-family: Courier New, Courier, Monospace; layout-grid-mode: line; vertical-align: bottom; text-align: left"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">/s/Gerrit Dispersyn</FONT></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">President and Chief Executive Officer</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">(Principal Executive Officer and</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Principal Financial Officer)</P></TD>
    <TD ROWSPAN="2" STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">March 27, 2019</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Gerrit Dispersyn, Dr. Med. Sc.</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-bottom: Black 1pt solid; vertical-align: bottom; text-align: left">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>/</B>s/Caitlin Kontulis</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Vice President of Finance and</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Administration and Secretary</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">(Principal Accounting Officer)</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">March 27, 2019</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Caitlin Kontulis</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-bottom: Black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>/s/</B>Robert J. Bitterman</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Director</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">March 27, 2019</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Robert J. Bitterman</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-bottom: Black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/Keith L. Brownlie</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Director</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">March 27, 2019</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Keith L. Brownlie</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center">&nbsp;</TD>
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line; text-align: center">&nbsp;</TD></TR>
</TABLE>
<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 35%; border-bottom: Black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/Geert Cauwenbergh</P></TD>
    <TD ROWSPAN="2" STYLE="width: 48%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Director</P></TD>
    <TD ROWSPAN="2" STYLE="width: 17%">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">March 27, 2019</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Geert Cauwenbergh, Dr. Med. Sc.</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-bottom: Black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/H. Paul Dorman</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Director</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">March 27, 2019</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">H. Paul Dorman</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-bottom: Black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/Jonathan Freeman</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Director</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">March 27, 2019</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Jonathan E. Freeman, Ph.D.</FONT></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="border-bottom: Black 1pt solid">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>&nbsp;</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">/s/Curtis A. Lockshin</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Director</P></TD>
    <TD ROWSPAN="2">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">&nbsp;</P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">March 27, 2019</P></TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="font-family: Courier New, Courier, Monospace; layout-grid-mode: line"><FONT STYLE="font-family: Times New Roman, Times, Serif; font-size: 10pt">Curtis A. Lockshin, Ph.D.</FONT></TD></TR>
</TABLE>
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[{"type": "S-8", "sequence": "1", "filename": "phio_s8.htm", "description": "FORM S-8 REGISTRATION STATEMENT", "secsgml_size_bytes": 108614}]
{"company-data": {"conformed-name": "Phio Pharmaceuticals Corp.", "cik": "0001533040", "assigned-sic": "2834", "irs-number": "000000000", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-230547", "film-number": "19709157"}, "business-address": {"street1": "257 SIMARANO DRIVE", "street2": "SUITE 101", "city": "MARLBOROUGH", "state": "MA", "zip": "01752", "phone": "(508) 767-3861"}, "mail-address": {"street1": "257 SIMARANO DRIVE", "street2": "SUITE 101", "city": "MARLBOROUGH", "state": "MA", "zip": "01752"}, "former-company": {"former-conformed-name": "RXi Pharmaceuticals Corp", "date-changed": "20111019"}}
As filed
with the Securities and Exchange Commission on March 27, 2019
Registration
No. 333-
Table of Contents
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
____________________
FORM S-8
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933
PHIO PHARMACEUTICALS CORP.
(Exact Name of Registrant as Specified
in the Charter)
Delaware
45-3215903
(State or other jurisdiction of incorporation or organization)
(I.R.S. Employer Identification No.)
257 Simarano Drive, Suite 101
Marlborough, MA
01752
(Address
    of principal executive offices)
(Zip
    Code)
Non-Plan Stock Compensation Election
and Terms and Conditions
(Full
title of the plan)
Gerrit
Dispersyn, Dr. Med. Sc.
President & Chief Executive Officer
Phio Pharmaceuticals Corp.
257 Simarano Drive, Suite 101
Marlborough, Massachusetts 01752
(508) 767-3861
(Name, address and telephone number, including area code, of agent for service)
Copies to:
Ryan A. Murr
Gibson, Dunn & Crutcher LLP
555 Mission Street, Suite 3000
San Francisco, CA 94105
Telephone: (415)393-8373
Facsimile: (415) 374 - 8430
Indicate by check mark whether the registrant is a large accelerated
filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions
of "large accelerated filer," "accelerated filer," "smaller reporting company" and "emerging
growth company" in Rule 12b-2 of the Exchange Act.
Large accelerated filer ☐
Accelerated filer ☐
Non-accelerated
filer ☒
Smaller
reporting company ☒
Emerging growth company ☐
If an emerging growth company, indicate by check mark if the
registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards
provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐
CALCULATION OF REGISTRATION FEE
Title
    of Securities to be Registered
Amount
    to be Registered (1)
Proposed
    Maximum Offering Price Per Share (3)
Proposed
    Maximum Aggregate Offering Price (3)
Amount
    of Registration Fee
Common
    Stock, par value $0.0001 per share ("Common Stock")
446,334(2)
$0.4302
$191,990.56
$23.27
(1)
Pursuant to Rule 416(a) under the
                                  Securities Act of 1933, as amended (the "Securities Act"), this Registration Statement
                                  also covers such additional shares of Common Stock as may be issued in respect of the securities
                                  registered by this Registration Statement as a result of any stock dividend, stock split, recapitalization
                                  or other similar transaction.
(2)
This Registration Statement covers
                                  the resale of 446,334 shares of Common Stock that have been previously issued to Dr. Geert Cauwenbergh
                                  (the "Selling Stockholder") in the form of restricted shares subject to time-based
                                  vesting conditions. Such shares were granted to the Selling Stockholder by Phio Pharmaceuticals
                                  Corp. (the "Company") following the Selling Stockholder's election to receive
                                  such shares in lieu of cash-based compensation for his services to the Company as its President
                                  and Chief Executive Officer. The Selling Stockholder's election is memorialized in the
                                  Non-Stock Plan Compensation Election and Terms and Conditions, dated August 31, 2018, as amended
                                  by Amendment No. 1 to the Non-Plan Stock Compensation Election and Terms and Conditions, dated
                                  December 19, 2018, and Amendment No. 2 to the Non-Plan Stock Compensation Election and Terms
                                  and Conditions, dated February 14, 2019.
(3)
Calculated pursuant to Rule 457(h)
                                  of the Securities Act solely for the purpose of computing the amount of the registration fee,
                                  on the basis of the average of the high and low prices of the Common Stock quoted on The Nasdaq
                                  Capital Market on March 20, 2019.
EXPLANATORY NOTE
Phio Pharmaceuticals Corp. (the "Company"
or the "Registrant") has prepared this Registration Statement on Form S-8 (the "Registration Statement")
in accordance with the requirements of Form S-8 under the Securities Act of 1933, as amended (the "Securities Act"),
to register the resale of up to 446,334 shares (the "Shares") of its Common Stock, par value $0.0001 per share, issued
prior to the filing of this Registration Statement and held by the Selling Stockholder named herein in connection with such Selling
Stockholder's provision of services to the Registrant.
This Registration Statement contains two
parts. The first part contains a "reoffer" prospectus prepared in accordance with Part I of Form S-3 (in accordance
with Instruction C of the General Instructions to Form S-8). The reoffer prospectus permits reoffers and resales of those shares
referred to above that constitute "restricted securities," within the meaning of Form S-8, by the Selling Stockholder
named herein. The second part contains information required to be set forth in the Registration Statement pursuant to Part II of
Form S-8. The Company will provide, without charge, to any person, upon written or oral request of such person, a copy of each
document incorporated by reference in Item 3 of Part II of this Registration Statement (which documents are also incorporated by
reference in the reoffer prospectus as set forth in Form S-8), other than exhibits to such documents that are not specifically
incorporated by reference.
PROSPECTUS
446,334 SHARES
PHIO PHARMACEUTICALS CORP.
COMMON STOCK
This prospectus relates to 446,334 shares
(the "Shares") of common stock, par value $0.0001 per share (the "Common Stock") of Phio Pharmaceuticals
Corp. (the "Company") which may be offered from time to time by the Selling Stockholder of the Company, named herein,
for such Selling Stockholder's own account. We will not receive any proceeds from any sale of Common Stock offered pursuant
to this prospectus.
The Selling Stockholder may offer and sell
the Shares at various times and in various types of transactions, including sales in the open market, sales in negotiated transactions
and sales by a combination of these methods. The Shares may be sold at the market price of the Common Stock at the time of a sale,
at prices relating to the market price over a period of time, or at prices negotiated with the buyers of shares. The Shares may
be sold through underwriters or dealers which the Selling Stockholder may select. If underwriters or dealers are used to sell the
Shares, we will name them and describe their compensation in a prospectus supplement. For a description of the various methods
by which the Selling Stockholder may offer and sell the Shares described in this prospectus, see the section entitled "Plan
of Distribution."
Our Common Stock is quoted on the Nasdaq
Capital Market under the symbol "PHIO." On March 26, 2019, the closing price of our Common stock was $0.425.
Investing in our Common Stock
involves risks. See the sections entitled "
Disclosure Regarding Forward-Looking Statements
" on
page 2 and "
Risk Factors
" on page 2  of this prospectus to read about factors to consider in
connection with purchasing our Common Stock.
Neither the Securities and Exchange Commission
nor any state securities commission has approved or disapproved these securities, or determined if this prospectus is truthful
or complete. Any representation to the contrary is a criminal offense.
The date of this prospectus
is March 27, 2019
TABLE OF CONTENTS
Page
THE COMPANY
1
DISCLOSURE REGARDING FORWARD-LOOKING STATEMENTS
2
RISK FACTORS
2
USE OF PROCEEDS
2
SELLING STOCKHOLDER
2
PLAN OF DISTRIBUTION
3
LEGAL MATTERS
3
EXPERTS
3
PART I
INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
4
PART II
INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
4
EXHIBIT INDEX
8
SIGNATURES
9
i
THE COMPANY
Unless otherwise noted, (1) the term "Phio" refers
to Phio Pharmaceuticals Corp. and our subsidiary, MirImmune, LLC and (2) the terms "Company," "we," "us"
and "our" refer to the ongoing business operations of Phio and MirImmune, LLC, whether conducted through Phio or MirImmune,
LLC.
Phio Pharmaceuticals Corp. is a biotechnology
company developing the next generation of immuno-oncology therapeutics based on our self-delivering RNAi ("
sd-rxRNA
®
")
therapeutic platform. The Company's efforts are focused on developing sd-rxRNA therapeutic compounds to be used in the context
of adoptive cell transfer by targeting checkpoints or other gene targets, or to be used in immunotherapy following intra-tumoral
injections. We aim to maximize the power of our sd-rxRNA therapeutic compounds by weaponizing therapeutic immune effector cells
to attack cancer, and to make tumors more susceptible to such attacks, and ultimately provide patients battling cancers with a
powerful new treatment option that goes beyond current treatment modalities.
In
January 2017, the Company entered into a Stock Purchase Agreement pursuant to which it acquired all of the issued and outstanding
shares of capital stock of MirImmune Inc. ("
MirImmune
") for an aggregate of 275,036 shares of common stock of
the Company and 1,118,224 shares of the Company's Series C Convertible Preferred Stock. With the approval of the Company's
stockholders at the 2017 Annual Meeting of Stockholders, every ten shares of the Series C Convertible Preferred Stock issued and
outstanding were automatically converted into one share of common stock.
Prior
to the Company's acquisition of MirImmune, our principal activities consisted of the preclinical and clinical development
of the Company's sd-rxRNA compounds and topical immunotherapy agent in the areas of dermatology and ophthalmology. In January
2018, after a thorough review of its business operations, development programs and financial resources, the Company made a strategic
decision to focus its efforts solely on immuno-oncology to accelerate growth and support a potential return on investment for its
stockholders. In connection with this decision, the Company completed all open clinical trials in dermatology and ophthalmology
with RXI-109, our first sd-rxRNA clinical candidate, and Samcyprone
®
, and reported out on the results of those clinical
studies in 2018. The Company intends to seek a partner and/or out-licensee for its dermatology program and its ophthalmology program
to continue with their development. The Company's current business strategy solely focuses on the development of immuno-oncology
therapeutics utilizing our proprietary sd-rxRNA technology.
On
November 19, 2018, the Company changed its name from RXi Pharmaceuticals Corporation to Phio Pharmaceuticals Corp., which reflects
the Company's transition from a platform company to one that is fully committed to develop groundbreaking immuno-oncology
therapeutics.
Our development efforts are based on our
broadly patented sd-rxRNA technology platform. Our sd-rxRNA compounds do not require a delivery vehicle to penetrate into tissues
and cells and are designed to "silence," or down-regulate, the expression of a specific gene that may be over-expressed
in a disease condition. We believe that our sd-rxRNA platform uniquely positions the Company in the field of immuno-oncology because
of this and for the following reasons:
·
Our sd-rxRNA compounds not require facilitated delivery (mechanical or formulation);
·
Can target multiple genes (i.e. multiple immunosuppression pathways) in a single therapeutic entity;
·
Demonstrate efficient uptake of sd-rxRNA to immune cells;
·
Silencing by sd-rxRNA has been shown to have a sustained, or long-term, effect
in vivo
;
·
Favorable clinical safety profile of sd-rxRNA with local administration; and
·
Can be readily manufactured under current good manufacturing practices.
We are incorporated
in Delaware, and our principal executive offices are located at 257 Simarano Drive, Suite 101, Marlborough, Massachusetts 01752,
and our telephone number is (508) 767-3861. Additional information regarding the Company is set forth in the Company's Annual
Report on Form 10-K for the fiscal year ended December 31, 2018 (which is incorporated herein by reference).
1
DISCLOSURE REGARDING
FORWARD-LOOKING STATEMENTS
This report contains forward-looking statements
within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements can be identified by words
such as "intends," "believes," "anticipates," "indicates," "plans,"
"expects," "suggests," "may," "should," "potential," "designed
to," "will" and similar references, although not all forward-looking statements contain these words. Forward-looking
statements are neither historical facts nor assurances of future performance. These statements are based only on our current beliefs,
expectations and assumptions regarding the future of our business, future plans and strategies, projections, anticipated events
and trends, the economy and other future conditions. Because forward-looking statements relate to the future, they are subject
to inherent uncertainties, risks and changes in circumstances that are difficult to predict and many of which are outside of our
control. Our actual results and financial condition may differ materially from those indicated in the forward-looking statements
as a result of a number of important factors, including those identified in this Registration Statement on Form S-8 under the heading
"Risk Factors" and in other filings the Company periodically makes with the Securities and Exchange Commission. Therefore,
you should not rely on any of these forward-looking statements. Forward-looking statements contained in this Registration Statement
on Form S-8 speak as of the date hereof and the Company does not undertake to update any of these forward-looking statements to
reflect a change in its views or events or circumstances that occur after the date of this report.
RISK FACTORS
Investing in our securities involves a high
degree of risk.  You should carefully consider the risks and uncertainties described in the documents incorporated herein
by reference, as well as other information we include or incorporate by reference.  Our business, financial condition or results
of operations could be materially adversely affected by the materialization of any of these risks. The trading price of our
securities could decline due to the materialization of any of these risks, and you may lose all or part of your investment. 
This prospectus and the documents incorporated herein by reference also contain forward-looking statements that involve risks and
uncertainties.  Actual results could differ materially from those anticipated in these forward-looking statements as a result
of certain factors, including the risks described under the headings "Risk Factors" in the documents incorporated herein
by reference, including in our Annual Report on Form 10-K for the year ended December 31, 2018 and any risk factors set forth in
our other filings with the SEC pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, including our Quarterly Reports
on Form 10-Q and our Current Reports on Form 8-K, before making an investment decision.
USE OF PROCEEDS
The proceeds from the sale of the shares
offered pursuant to this prospectus are solely for the account of the Selling Stockholder. We will not receive any of the proceeds
from any sale of shares by the Selling Stockholder.
SELLING STOCKHOLDER
The Common Stock being registered by this
prospectus consists of 446,334 shares that are currently held by Dr. Geert Cauwenbergh, the Selling Stockholder, and were issued
to the Selling Stockholder pursuant to a written compensation contract by and between the Company and the Selling Stockholder in
connection with his service as the President and Chief Executive Officer of the Company.
We are registering these shares to permit
the Selling Stockholder to resell these shares when he deems appropriate. The Selling Stockholder may resell all, a portion, or
none of the shares, at any time and from time to time. The Selling Stockholder may also sell, transfer or otherwise dispose of
some or all of the shares in transactions exempt from the registration requirements of the Securities Act. We do not know when
or in what amounts the Selling Stockholders may offer the shares of common stock for sale under this prospectus.
The Selling Stockholder holds less than
5% of the Company's outstanding common stock and is an affiliate of the Company. The Selling Stockholder has served as the
President and Chief Executive Officer of the Company during the last three years. The following table sets forth: (i) the number
and percentage of shares of our common stock that the Selling Stockholder beneficially owned as of March 1, 2019 prior to the offering
for resale of the shares under this prospectus; (ii) the number of shares of our Common Stock that may be offered for resale for
the account of the Selling Stockholder under this prospectus; and (iii) the number and percentage of shares of our Common Stock
to be beneficially owned by the Selling Stockholder after the offering of the resale shares (assuming all of the offered resale
shares are sold by such Selling Stockholder).
Selling Stockholder
Number of Shares Beneficially Owned Prior to Offering
Number of Shared Being Offered
Number of Shares Beneficially Owned After the Offering
Number
Percent
Number
Percent
Dr. Geert Cauwenbergh
502,862
2.41%
446,334
56,528
*
*
Less than 1%
2
PLAN OF DISTRIBUTION
The purpose of this reoffer prospectus is
to allow the Selling Stockholder to offer for sale and sell all or a portion of his shares acquired in connection with the provision
of services to the Company. The Selling Stockholder may sell the shares of common stock registered pursuant to this reoffer prospectus
directly to purchasers or through broker-dealers or agents, who may receive compensation in the form of discounts, concessions
or commissions from the Selling Stockholder or the purchasers. These commissions as to any particular broker-dealer or agent may
be in excess of those customary in the types of transactions involved. Neither we nor the Selling Stockholder can presently estimate
the amount of this compensation.
The common stock offered under this reoffer
prospectus may be sold in one or more transactions at fixed prices, at prevailing market prices at the time of sale, at prices
related to the prevailing market prices, at varying prices determined at the time of sale, or at negotiated prices. These sales
may be effected in transactions, which may involve block transactions, on any national securities exchange on which the Company's
common stock may be then-listed.
The aggregate proceeds to the Selling Stockholder
from the sale of the shares will be the purchase price of the common stock less discounts and commissions, if any. The Selling
Stockholder reserves the right to accept and, together with his agents from time to time, to reject, in whole or in part, any proposed
purchase of the shares to be made directly or through agents. We will not receive any of the proceeds from a sale of the shares
by the Selling Stockholder.
The Selling Stockholder and any broker-dealers
or agents that participate in the sale of the shares may be deemed to be "underwriters" under the Securities Act. Any
discounts, commissions, concessions or profit they earn on any resale of the shares may be underwriting discounts and commissions
under the Securities Act. If the Selling Stockholder is an "underwriter" under the Securities Act, the Selling Stockholder
will be subject to the prospectus delivery requirements of the Securities Act.
The shares to be offered or resold by means
of this reoffer prospectus by the Selling Stockholder may not exceed, during any three-month period, the amount specified in Rule
144(e) under the Securities Act. In addition, any securities covered by this reoffer prospectus which qualify for sale pursuant
to Rule 144 of the Securities Act may be sold under Rule 144 of the Securities Act rather than pursuant to this reoffer prospectus.
There can be no assurance that the Selling
Stockholder will sell any or all of the securities offered by them hereby.
LEGAL MATTERS
We are being represented by Gibson,
Dunn & Crutcher LLP, who will pass upon the validity of the shares being offered by this prospectus.
EXPERTS
The consolidated financial
statements as of December 31, 2018 and 2017 and for each of the two years in the period ended December 31, 2018 incorporated by
reference in this Prospectus have been so incorporated in reliance on the report of BDO USA, LLP, an independent registered public
accounting firm, incorporated herein by reference, given on the authority of said firm as experts in auditing and accounting.
3
PART I
INFORMATION REQUIRED
IN THE SECTION 10(a) PROSPECTUS
Item 1.	Plan Information
Information required by Part I to be contained
in the Section 10(a) prospectus is omitted from this Registration Statement in accordance with Rule 428 under the Securities Act
of 1933, as amended (the "Securities Act"), and the Note to Part I of Form S-8.
PART II
INFORMATION REQUIRED
IN THE REGISTRATION STATEMENT
Item 3.	Incorporation of Documents by Reference.
The following documents filed by Phio Pharmaceuticals
Corp. (the "Registrant") with the Securities and Exchange Commission are incorporated herein by reference:
(1)
the Registrant's Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on March 27, 2019;
(2)
the Registrant's Current Reports on Form 8-K, filed with the SEC on January 28, 2019 and February 15, 2019; and
(3)
the description of the Registrant's Common Stock, par value $0.0001 per share, which is contained in the Registrant's
registration statement on Form 8-A filed with the SEC under Section 12 of the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), on February 7, 2014, including any amendments or reports filed for the purpose of updating such description.
All documents subsequently filed by the
Registrant pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing of a post-effective amendment
to this Registration Statement that indicates that all securities offered have been sold or which deregisters all securities then
remaining unsold, shall be deemed to be incorporated herein by reference from the date of filing of such documents. Any statement
contained herein or in a document incorporated or deemed to be incorporated by reference herein shall be deemed to be modified
or superseded for purposes of this Registration Statement to the extent that a statement contained herein or in any subsequently
filed document which also is incorporated or is deemed to be incorporated by reference herein modifies or supersedes such earlier
statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute part
of this Registration Statement.
Item 4.	Description of Securities.
Not applicable.
Item 5.	Interests of Named Experts
and Counsel.
Not applicable.
Item 6.	Indemnification of Directors
and Officers.
Section 145 of the Delaware General Corporation
Law (the "DGCL") provides that a corporation may indemnify any current or former director, officer or employee or other
individual against expenses, judgments, fines and amounts paid in settlement in connection with civil, criminal, administrative
or investigative actions or proceedings, other than a derivative action by or in the right of the corporation, if the director,
officer, employee or other individual acted in good faith and in a manner he or she reasonably believed to be in or not opposed
to the best interests of the corporation, and, with respect to any criminal action or proceeding, if he or she had no reasonable
cause to believe his or her conduct was unlawful. A similar standard is applicable in the case of derivative actions, except that
indemnification extends only to expenses incurred in connection with the defense or settlement of such actions, and the statute
requires court approval before there can be any indemnification where the person seeking indemnification has been found liable
to the corporation. The statute provides that it is not exclusive of other indemnification that may be granted by a corporation's
by-laws, disinterested director vote, stockholder vote, agreement or otherwise.
4
Our certificate of incorporation provides
that we will indemnify to the fullest extent authorized or permitted by the DGCL or any other applicable law as now or hereafter
in effect any person made, or threatened to be made, a defendant or witness to any action, suit or proceeding (whether civil, criminal
or otherwise) by reason of the fact that he is or was a director of our corporation or by reason of the fact that such director,
at our request, is or was serving any other corporation, partnership, joint venture, trust, employee benefit plan or other enterprise
in any capacity. Our certificate of incorporation also provides that no amendment or repeal of the certificate of incorporation
will apply to or have any effect on any right to indemnification provided in the certificate of incorporation with respect to any
acts or omissions occurring prior to such amendment or repeal.
As permitted by the DGCL, our bylaws, as
amended, provide that we will indemnify to the fullest extent authorized or permitted by applicable law as now or hereafter in
effect any person who was or is made, or is threatened to be made, a party or is otherwise involved in any action, suit or proceeding
(whether civil, criminal, administrative or investigative), by reason of the fact that he (or a person for whom he is the legal
representative) is or was a director or officer of our corporation, is or was serving at our request as a director, officer, employee,
member, trustee or agent of another corporation or of a partnership, joint venture, trust, nonprofit entity or other enterprise.
Consequently, no director of the corporation
will be personally liable to the corporation or its stockholders for monetary damages for any breach of fiduciary duty by such
a director as a director. However, notwithstanding the preceding sentence, a director will be liable to the extent provided by
Delaware law (1) for any breach of the director's duty of loyalty to the corporation or its stockholders, (2) for acts or
omissions not in good faith or which involve intentional misconduct or a knowing violation of law, (3) for payments of unlawful
dividends or for unlawful stock repurchases or redemption, or (4) for any transaction from which the director derived an improper
personal benefit.
We have entered into indemnification agreements
with each of our executive officers and directors. These agreements provide that, subject to limited exceptions and among other
things, we will indemnify each of our executive officers and directors to the fullest extent permitted by law and advance expenses
to each indemnitee in connection with any proceeding in which a right to indemnification is available.
We also maintain insurance on behalf of
any person who is or was our director, officer, trustee, employee or agent or serving at our request as a director, officer, trustee,
employee or agent of another corporation, partnership, joint venture, trust, non-profit entity or other enterprise against any
liability asserted against the person and incurred by the person in any such capacity, or arising out of his or her status as such.
Insofar as indemnification for liabilities
arising under the Securities Act may be permitted for directors, officers, or persons who control us, we have been informed that,
in the opinion of the SEC, such indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.
Item 7.	Exemption from Registration
Claimed.
Not applicable.
Item 8.	Exhibits.
See exhibits listed
under Exhibit Index below.
Item 9.	Undertakings.
(a) The undersigned Registrant hereby undertakes:
(1) To file, during any period in which
offers or sales are being made, a post-effective amendment to this Registration Statement:
(i) To include any prospectus required
by Section 10(a)(3) of the Securities Act;
5
(ii) To reflect in the prospectus any facts
or events arising after the effective date of the Registration Statement (or the most recent post-effective amendment thereof)
which, individually or in the aggregate, represent a fundamental change in the information set forth in the Registration Statement.
Notwithstanding the foregoing, any increase or decrease in volume of securities offered (if the total dollar value of securities
offered would not exceed that which was registered) and any deviation from the low or high end of the estimated maximum offering
range may be reflected in the form of prospectus filed with the Commission pursuant to Rule 424(b) if, in the aggregate, the
changes in volume and price represent no more than 20% change in the maximum aggregate offering price set forth in the "Calculation
of Registration Fee" table in the effective registration statement; and
(iii) To include any material information
with respect to the plan of distribution not previously disclosed in the Registration Statement or any material change to such
information in the Registration Statement;
p
rovided, however,
that paragraphs (a)(1)(i) and (a)(1)(ii)
do not apply if the information required to be included in a post-effective amendment by those paragraphs is contained in reports
filed with or furnished to the Commission by the Registrant pursuant to Section 13 or Section 15(d) of the Securities Exchange
Act of 1934 that are incorporated by reference in the Registration Statement;
(2) That, for the purpose of determining
any liability under the Securities Act, each such post-effective amendment shall be deemed to be a new registration statement relating
to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial
bona fide
offering thereof; and
(3) To remove from registration by means
of a post-effective amendment any of the securities being registered which remain unsold at the termination of the offering.
(b) The undersigned Registrant hereby undertakes that, for purposes
of determining any liability under the Securities Act, each filing of the Registrant's annual report pursuant to Section 13(a)
or Section 15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan's annual report pursuant
to Section 15(d) of the Exchange Act) that is incorporated by reference in the Registration Statement shall be deemed to be a new
registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed
to be the initial
bona fide
offering thereof.
(c) Insofar as indemnification for liabilities arising under
the Securities Act may be permitted to directors, officers and controlling persons of the Registrant pursuant to the foregoing
provisions, or otherwise, the Registrant has been advised that in the opinion of the Commission such indemnification is against
public policy as expressed in the Act and is, therefore, unenforceable. In the event that a claim for indemnification against
such liabilities (other than the payment by the Registrant of expenses incurred or paid by a director, officer or controlling
person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or
controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel
the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such
indemnification by it is against public policy as expressed in the Act and will be governed by the final adjudication of such
issue.
7
EXHIBIT INDEX
Exhibit
        No.
Description
4.1
Amended and Restated Certificate of Incorporation of the Company
(incorporated by reference to Exhibit 3.2 of the Company's Current Report on Form 8-K filed on November 19, 2018)
4.2
Amended and Restated Bylaws of the Company
(incorporated by reference to Exhibit 3.3 of the Company's Current Report on Form 8-K filed on November 19, 2018)
5.1
Opinion of counsel
*
10.1
Non-Stock Plan Compensation Election and Terms and Conditions, dated August 31, 2018
(incorporated by reference to Exhibit 10.1 of the Company's Current Report on Form 8-K filed on September 4, 2018)
10.2
Amendment No. 1 to the Non-Plan Stock Compensation Election and Terms and Conditions, dated December 19, 2018
(incorporated by reference to Exhibit 10.1 of the Company's Current Report on Form 8-K filed on December 21, 2018)
10.3
Amendment No. 2 to the Non-Plan Stock Compensation Election and Terms and Conditions, dated February 14, 2019
(incorporated by reference to Exhibit 10.1 of the Company's Current Report on Form 8-K filed on February 15, 2019)
23.1
Consent of Independent Registered Public Accounting Firm
*
23.2
Consent of counsel (included in Exhibit 5.1)*
24
Power of Attorney
(included on signature page)*
* Filed herewith
8
SIGNATURES
Pursuant to the requirements of the Securities
Act of 1933, as amended, the Registrant certifies that it has reasonable grounds to believe that it meets all the requirements
for filing on Form S-8 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in Marlborough, Massachusetts, on March 27, 2019.
PHIO PHARMACEUTICS CORP.
By:
/s/Gerrit Dispersyn
Gerrit Dispersyn, Dr. Med. Sc.
President
and Chief Executive Officer
POWER OF ATTORNEY
KNOW ALL PERSONS BY THESE PRESENTS, that
each person whose signature appears below constitutes and appoints Gerrit Dispersyn, Dr. Med. Sc. as attorney-in-fact and agent,
with full power of substitution and resubstitution, in any and all capacities, to sign any and all amendments (including post-effective
amendments) to this registration statement, and to file the same, with all exhibits thereto and other documents in connection therewith,
with the Securities and Exchange Commission, granting unto said attorney-in-fact and agent, with full power to act alone, full
power and authority to do and perform each and every act and thing requisite and necessary to be done in connection therewith,
as fully for all intents and purposes as he might or could do in person, hereby ratifying and confirming all that said attorney-in-fact
and agent, or his substitute or substitutes, may do or cause to be done by virtue thereof.
Pursuant to the requirements of the Securities Act of 1933,
this registration statement has been signed by the following persons in the capacities and on the dates indicated.
Signature
Title
Date
/s/Gerrit Dispersyn
President and Chief Executive Officer
(Principal Executive Officer and
Principal Financial Officer)
March 27, 2019
Gerrit Dispersyn, Dr. Med. Sc.
/
s/Caitlin Kontulis
Vice President of Finance and
Administration and Secretary
(Principal Accounting Officer)
March 27, 2019
Caitlin Kontulis
/s/
Robert J. Bitterman
Director
March 27, 2019
Robert J. Bitterman
/s/Keith L. Brownlie
Director
March 27, 2019
Keith L. Brownlie
/s/Geert Cauwenbergh
Director
March 27, 2019
Geert Cauwenbergh, Dr. Med. Sc.
/s/H. Paul Dorman
Director
March 27, 2019
H. Paul Dorman
/s/Jonathan Freeman
Director
March 27, 2019
Jonathan E. Freeman, Ph.D.
/s/Curtis A. Lockshin
Director
March 27, 2019
Curtis A. Lockshin, Ph.D.
9