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<TITLE>FORM S-8</TITLE>
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 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>As Filed with the Securities and Exchange Commission on August&nbsp;5, 2013
</B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="right"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Registration No.&nbsp;333-&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </B></FONT></P>
<P STYLE="font-size:4px;margin-top:0px;margin-bottom:0px">&nbsp;</P> <P STYLE="line-height:0px;margin-top:0px;margin-bottom:0px;border-bottom:0.5pt solid #000000">&nbsp;</P>
<P STYLE="line-height:3px;margin-top:0px;margin-bottom:2px;border-bottom:0.5pt solid #000000">&nbsp;</P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="5"><B>UNITED STATES </B></FONT></P>
<P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="5"><B>SECURITIES AND EXCHANGE COMMISSION </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="3"><B>Washington, D.C. 20549 </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><center>
<P STYLE="line-height:6px;margin-top:0px;margin-bottom:2px;border-bottom:1pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="5"><B>FORM <FONT
STYLE="white-space:nowrap">S-8</FONT> </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="5"><B>REGISTRATION STATEMENT </B></FONT></P>
<P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="3"><B><I>UNDER </I></B></FONT></P>
<P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="3"><B><I>THE SECURITIES ACT OF 1933 </I></B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><center>
<P STYLE="line-height:6px;margin-top:0px;margin-bottom:2px;border-bottom:1pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="6"><B>Mast
Therapeutics, Inc. </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>(Exact name of registrant as specified in its charter) </B></FONT></P>
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><center> <P STYLE="line-height:6px;margin-top:0px;margin-bottom:2px;border-bottom:1pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Delaware</B></FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>84-1318182</B></FONT></TD></TR>
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<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>(State or other jurisdiction of</B></FONT></P>
<P STYLE="margin-top:0px;margin-bottom:1px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>incorporation or organization)</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>(I.R.S. Employer</B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="1"><B>Identification No.)</B></FONT></P></TD></TR>
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<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>12390 El Camino Real, Suite 150</B></FONT></P>
<P STYLE="margin-top:0px;margin-bottom:1px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>San Diego, California</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>92130</B></FONT></TD></TR>
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<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>(Address of Principal Executive Offices)</B></FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>(Zip Code)</B></FONT></TD></TR>
</TABLE> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><center> <P STYLE="line-height:6px;margin-top:0px;margin-bottom:2px;border-bottom:1pt solid #000000;width:21%">&nbsp;</P></center>
<P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Mast Therapeutics, Inc. 2013 Omnibus Incentive Plan </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="1"><B>(Full title of the plans) </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><center>
<P STYLE="line-height:6px;margin-top:0px;margin-bottom:2px;border-bottom:1pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Patrick L.
Keran </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>President and Chief Operating Officer </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="2"><B>Mast Therapeutics, Inc. </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>12390 El Camino Real, Suite 150 </B></FONT></P>
<P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>San Diego, California, 92130 </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="1"><B>(Name and Address of Agent For Service) </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>(858) 552-0866 </B></FONT></P>
<P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>(Telephone number, including area code, of agent for service) </B></FONT></P>
<P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B><I>Copies to: </I></B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="2"><B>Kirt W. Shuldberg, Esq. </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Sheppard, Mullin, Richter &amp; Hampton LLP
</B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>12275 El Camino Real, Suite 200 </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="2"><B>San Diego, California 92130 </B></FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>(858) 720-8900 </B></FONT></P>
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><center> <P STYLE="line-height:6px;margin-top:0px;margin-bottom:2px;border-bottom:1pt solid #000000;width:21%">&nbsp;</P></center> <P STYLE="margin-top:12px;margin-bottom:0px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of &#147;large accelerated
filer,&#148; &#147;accelerated filer,&#148; and &#147;smaller reporting company&#148; in Rule&nbsp;12b-2 of the Exchange Act. (Check one): </FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2">Large&nbsp;Accelerated&nbsp;filer</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2"><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT></FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2">Accelerated&nbsp;filer</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2"><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT></FONT></TD></TR>
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<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
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<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2">Non-accelerated filer</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2"><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT>&nbsp;&nbsp;(Do not check if a smaller reporting company)</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2">Smaller&nbsp;reporting&nbsp;company</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT STYLE="font-family:Times New Roman" SIZE="2"><FONT STYLE="FONT-FAMILY:WINGDINGS">&#120;</FONT></FONT></TD></TR>
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<P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>CALCULATION OF REGISTRATION FEE </B></FONT></P>
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<TD VALIGN="bottom" ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Title&nbsp;of&nbsp;Securities&nbsp;to&nbsp;be&nbsp;Registered</B></FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Amount&nbsp;to&nbsp;be<BR>Registered&nbsp;(1)</B></FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Proposed Maximum<BR>Offering&nbsp;Price&nbsp;<BR>Per&nbsp;Share</B></FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Proposed&nbsp;Maximum<BR>Aggregate&nbsp;Offering<BR>Price</B></FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Amount&nbsp;of&nbsp;<BR>Registration&nbsp;Fee</B></FONT></TD></TR>
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<TD VALIGN="top" STYLE="BORDER-TOP:1px solid #000000"> <P STYLE="margin-left:1.00em; text-indent:-1.00em"><FONT STYLE="font-family:Times New Roman" SIZE="2">Common Stock, par value $0.001 per share: To be issued under the Mast Therapeutics, Inc.
2013 Omnibus Incentive Plan (2)</FONT></P></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">10,556,050&nbsp;shares</FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">$0.46(3)</FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">$4,855,783(3)</FONT></TD>
<TD VALIGN="bottom" STYLE="BORDER-LEFT:1px solid #000000; BORDER-TOP:1px solid #000000"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center" STYLE="BORDER-TOP:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">$663</FONT></TD></TR>
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<TD COLSPAN="9" VALIGN="bottom"> <P STYLE="border-top:1px solid #000000">&nbsp;</P></TD></TR>
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<TD COLSPAN="9" VALIGN="bottom"> <P STYLE="border-top:1px solid #000000">&nbsp;</P></TD></TR>
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<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2">(1)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Pursuant to Rule 416 under the Securities Act of 1933, as amended (the &#147;Securities Act&#148;), this Registration Statement shall also cover any additional shares
of common stock that may become issuable under the Mast Therapeutics, Inc. 2013 2008 Omnibus Incentive Plan (the &#147;2013 Plan&#148;) by reason of any stock split, stock dividend, recapitalization, or any other similar transaction effected without
receipt of consideration that results in an increase in the Registrant&#146;s outstanding shares of common stock. </FONT></TD></TR></TABLE>
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<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2">(2)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Represents (i) 6,539,207 shares of the Registrant&#146;s common stock that became available for issuance on June 19, 2013 under the 2013 Plan, (ii) 4,016,843 shares
that may be added to the 2013 Plan upon the forfeiture, expiration or cash settlement of outstanding awards granted under the Registrant&#146;s Amended and Restated 2008 Omnibus Incentive Plan, 2008 Omnibus Incentive Plan, and 2005 Equity Incentive
Plan (the &#147;Prior Plans&#148;). As of June 19, 2013, no new awards may be granted under any of the Prior Plans. </FONT></TD></TR></TABLE>
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<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2">(3)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Estimated pursuant to Rules 457(c) and 457(h) under the Securities Act solely for the purpose of calculating the registration fee, based on the average of the high and
low prices of the Registrant&#146;s common stock on the NYSE MKT equities market on July&nbsp;30, 2013. </FONT></TD></TR></TABLE> <P STYLE="margin-top:12px;margin-bottom:0px"><FONT STYLE="font-family:Times New Roman" SIZE="2">The Registration
Statement shall become effective upon filing in accordance with Rule 462(a) under the Securities Act. </FONT></P> <P STYLE="font-size:10px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<P STYLE="line-height:0px;margin-top:0px;margin-bottom:0px;border-bottom:0.5pt solid #000000">&nbsp;</P> <P STYLE="line-height:3px;margin-top:0px;margin-bottom:2px;border-bottom:0.5pt solid #000000">&nbsp;</P>

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 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>PART I </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="2"><B>INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS </B></FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;1.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Plan Information.* </B></FONT></TD></TR></TABLE> <P STYLE="font-size:6px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;2.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Registrant Information and Employee Plan Annual Information.* </B></FONT></TD></TR></TABLE> <P STYLE="font-size:6px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD WIDTH="2%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2">*</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">The documents containing the information specified in &#147;Item 1. Plan Information&#148; and &#147;Item 2. Registrant Information and Employee Plan Annual
Information&#148; of Form S-8 will be sent or given to participants of the 2013 Plan, as specified by Rule 428(b)(1) under the Securities Act. Such documents are not required to be, and are not, filed with the Securities and Exchange Commission (the
&#147;SEC&#148;) either as part of this Registration Statement or as a prospectus or prospectus supplement pursuant to Rule 424 under the Securities Act. These documents and the documents incorporated by reference in this Registration Statement
pursuant to Item&nbsp;3 of Part II of Form S-8, taken together, constitute a prospectus that meets the requirements of Section&nbsp;10(a) of the Securities Act. </FONT></TD></TR></TABLE> <P STYLE="margin-top:18px;margin-bottom:0px" ALIGN="center"><FONT
STYLE="font-family:Times New Roman" SIZE="2"><B>PART II </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>INFORMATION REQUIRED IN REGISTRATION STATEMENT </B></FONT></P>
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;3.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Incorporation of Documents by Reference. </B></FONT></TD></TR></TABLE> <P STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT
STYLE="font-family:Times New Roman" SIZE="2">The SEC allows the Registrant to &#147;incorporate by reference&#148; information contained in documents that the Registrant files with the SEC. This means that the Registrant can disclose important
information to you by referring you to those documents and that the information in this Registration Statement is not complete. You should read the information incorporated by reference for more detail. The Registrant incorporates by reference in
two ways. First, the Registrant incorporates by reference by listing below certain documents that the Registrant has already filed with the SEC. The information in these documents is considered part of this Registration Statement. Second, the
information in documents that the Registrant files in the future will update and supersede the information currently in, and be incorporated by reference in, this Registration Statement. </FONT></P>
<P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">The Registrant incorporates by reference into this Registration Statement the documents listed below and any filings it makes with the
SEC pursuant to Section&nbsp;13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the &#147;Exchange Act&#148;), after the date of this Registration Statement until the filing of a post-effective amendment that terminates
this offering (in each case, except for the information furnished under Item&nbsp;2.02 or Item&nbsp;7.01 in any current report on Form 8-K or amendment to such current report): </FONT></P>
<P STYLE="font-size:6px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TD WIDTH="4%"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2">(a)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">The Registrant&#146;s Annual Report on Form 10-K for the fiscal year ended December&nbsp;31, 2012, filed with the SEC on March&nbsp;19, 2013, including all material
incorporated by reference therein; </FONT></TD></TR></TABLE> <P STYLE="font-size:6px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="4%"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2">(b)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">The Registrant&#146;s Quarterly Reports on Form&nbsp;10-Q for the quarters ended March&nbsp;31, 2013 and June&nbsp;30, 2013, filed with the SEC on May&nbsp;15, 2013 and
August&nbsp;5, 2013, respectively, including all material incorporated by reference therein; </FONT></TD></TR></TABLE> <P STYLE="font-size:6px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="4%"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2">(c)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">The Registrant&#146;s Current Reports on Form&nbsp;8-K filed on January&nbsp;3, 2013,&nbsp;February&nbsp;8, 2013,&nbsp;February&nbsp;26, 2013,&nbsp;March&nbsp;1,
2013,&nbsp;March&nbsp;12, 2013,&nbsp;June&nbsp;17, 2013 and June&nbsp;21, 2013, including all material incorporated by reference therein; and </FONT></TD></TR></TABLE> <P STYLE="font-size:6px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="4%"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD WIDTH="4%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2">(d)</FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">The description of the Registrant&#146;s common stock contained in the Registrant&#146;s Registration Statement on <FONT STYLE="white-space:nowrap">Form&nbsp;8-A</FONT>
filed with the SEC on April&nbsp;27, 2004, pursuant to Section&nbsp;12(b) of the Exchange Act, including any amendments or reports filed for the purpose of updating such descriptions. </FONT></TD></TR></TABLE>
 <p STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">2 </FONT></P>


<p Style='page-break-before:always'>
<HR  SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">

 <P STYLE="margin-top:0px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">Any statement contained in a document incorporated or deemed to be incorporated by reference
herein shall be deemed to be modified or superseded for the purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document which also is or deemed to be incorporated by reference
herein modifies or supersedes such statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this Registration Statement. </FONT></P>
<P STYLE="font-size:18px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;4.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Description of Securities. </B></FONT></TD></TR></TABLE>
<P STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">Not applicable. </FONT></P> <P STYLE="font-size:18px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;5.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Interests of Named Experts and Counsel. </B></FONT></TD></TR></TABLE> <P STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Not applicable. </FONT></P> <P STYLE="font-size:18px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;6.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Indemnification of Directors and Officers. </B></FONT></TD></TR></TABLE> <P STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Section&nbsp;145 of the Delaware General Corporation Law authorizes a corporation to indemnify its directors and officers against liabilities arising out of actions, suits and proceedings to which they
are made or threatened to be made a party by reason of the fact of their prior or current service to the corporation as a director or officer, in accordance with the provisions of Section&nbsp;145, which are sufficiently broad to permit
indemnification under certain circumstances for liabilities arising under the Securities Act. The indemnity may cover expenses (including attorneys&#146; fees) judgments, fines and amounts paid in settlement actually and reasonably incurred by the
director or officer in connection with any such action, suit or proceeding. Section&nbsp;145 permits corporations to pay expenses (including attorneys&#146; fees) incurred by directors and officers in advance of the final disposition of such action,
suit or proceeding. In addition, Section&nbsp;145 provides that a corporation has the power to purchase and maintain insurance on behalf of its directors and officers against any liability asserted against them and incurred by them in their capacity
as a director or officer, or arising out of their status as such, whether or not the corporation would have the power to indemnify the director or officer against such liability under Section&nbsp;145. </FONT></P>
<P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">The Registrant&#146;s amended and restated certificate of incorporation, as amended (the &#147;Certificate of Incorporation&#148;)
provides that, to the fullest extent permitted by the Delaware General Corporation Law, (1)&nbsp;a director shall not be personally liable to the Registrant or its stockholders for monetary damages for breach of fiduciary duty as a director, and
(2)&nbsp;the Registrant shall indemnify any director or officer made a party to an action or proceeding, whether criminal, civil, administrative or investigative, by reason of the fact of such person&#146;s current or prior service as a director or
officer of the Registrant, any predecessor of the Registrant or any other enterprise per the Registrant&#146;s or any predecessor to the Registrant&#146;s request. </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT
STYLE="font-family:Times New Roman" SIZE="2">The Registrant amended and restated bylaws (the &#147;Bylaws&#148;), provide that (a)&nbsp;the Registrant shall indemnify its directors and officers to the maximum extent and in the manner permitted by
the Delaware General Corporation Law against expenses (including attorneys&#146; fees), judgments, fines, ERISA excise taxes, settlements and other amounts actually and reasonably incurred in connection with any proceeding, whether civil, criminal,
administrative or investigative, arising by reason of the fact that such person is or was an agent of the corporation, subject to certain limited exceptions, (b)&nbsp;the Registrant shall advance expenses incurred by any director or officer prior to
the final disposition of any proceeding to which the director or officer was or is or is threatened to be made a party promptly following a request therefore, subject to certain limited exceptions, and (c)&nbsp;the rights conferred in the Bylaws are
not exclusive. </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">The Registrant has entered into indemnification agreements with each of its directors and executive officers
to give such directors and officers additional contractual assurances regarding the scope of the indemnification set forth in the Certificate of Incorporation and the Bylaws and to provide additional procedural protections. These agreements, among
other things, provide that the Registrant will indemnify its directors and executive officers for expenses (including attorneys&#146; fees), judgments, fines, penalties and amounts paid in settlement (including all interest, assessments and other
charges paid or payable in connection therewith) actually and reasonably incurred by a director or executive officer in connection with any action or proceeding to which such person was, is or is threatened to be made a party, a witness or other
participant by reason of such person&#146;s services as a director or executive officer of the Registrant, any of the Registrant&#146;s subsidiaries or any other company or enterprise to which the person provides services at the Registrant&#146;s
request, and any federal, state, local or foreign taxes imposed on the director or executive officer as a result of the actual or deemed receipt of any payments under the indemnification agreements. In addition, the indemnification agreements
provide that, upon the request of a director or executive officer, the Registrant shall advance expenses (including attorneys&#146; fees) to the director or officer. The Registrant intends to enter into indemnification agreements with any new
directors and executive officers in the future. </FONT></P>
 <p STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">3 </FONT></P>


<p Style='page-break-before:always'>
<HR  SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">

 <P STYLE="margin-top:0px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">The Registrant has also obtained insurance policies covering its directors and officers with
respect to certain liabilities, including liabilities arising under the Securities Act. </FONT></P> <P STYLE="font-size:18px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;7.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Exemption From Registration Claimed. </B></FONT></TD></TR></TABLE> <P STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Not applicable. </FONT></P> <P STYLE="font-size:18px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;8.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Exhibits. </B></FONT></TD></TR></TABLE> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE" ALIGN="center">


<TR>
<TD></TD>
<TD VALIGN="bottom" WIDTH="5%"></TD>
<TD WIDTH="44%"></TD>
<TD VALIGN="bottom" WIDTH="4%"></TD>
<TD WIDTH="44%"></TD></TR>
<TR>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:39pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Exhibit&nbsp;No.</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:85pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Description of Document</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:94pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Incorporation by Reference</B></FONT></P></TD></TR>


<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;4.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Composite Amended and Restated Certificate of Incorporation, as amended, of the Registrant</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Registration Statement on Form S-1 on May 28, 2013 (SEC File No. 333-188870-13873232)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;4.2</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Certificate of Ownership and Merger, effective as of March 11, 2013</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on March 1, 2013 (SEC File No. 001-32157-13657723)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;4.3</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Amended and Restated Bylaws of the Registrant, effective as of March 11, 2013</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on March 1, 2013 (SEC File No. 001-32157-13657723)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;4.4</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of common stock certificate of the Registrant</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Annual Report on Form 10-K on March 19, 2013 (SEC File No. 001-32157-13702619)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;5.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Opinion of Sheppard, Mullin, Richter &amp; Hampton LLP</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">23.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Consent of PricewaterhouseCoopers LLP, Independent Registered Public Accounting Firm</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">23.2</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Consent of CohnReznick LLP, Independent Registered Public Accounting Firm</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">23.3</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Consent of Sheppard, Mullin, Richter &amp; Hampton LLP</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Included in Exhibit 5.1 filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">24.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Power of Attorney</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Included as part of the signature page to this Registration Statement</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Mast Therapeutics, Inc. 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.2</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of Non-Statutory Stock Option Grant Agreement&#151;Director (for grants to non-employee directors) under 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.3</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of Incentive Stock Option Grant Agreement (for grants to employees) under the 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.4</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of Non-Statutory Stock Option Grant Agreement (for grants to consultants) under the 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.5</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of Senior Executive Incentive Stock Option Grant Agreement (for grants to the Registrant&#146;s chief executive officer and president and chief operating officer) under the
2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.6</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of CMO Incentive Stock Option Grant Agreement (for grants to the Registrant&#146;s chief medical officer) under the 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
</TABLE>
 <p STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">4 </FONT></P>


<p Style='page-break-before:always'>
<HR  SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">


<TABLE STYLE="BORDER-COLLAPSE:COLLAPSE" BORDER="0" CELLPADDING="0" CELLSPACING="0" WIDTH="100%">
<TR>
<TD WIDTH="8%" VALIGN="top" ALIGN="left"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Item&nbsp;9.</B></FONT></TD>
<TD ALIGN="left" VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Undertakings. </B></FONT></TD></TR></TABLE> <P STYLE="margin-top:6px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(a) The
undersigned Registrant hereby undertakes: </FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px; margin-left:8%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(1) To file, during any period in which offers or sales are being made, a
post-effective amendment to this Registration Statement: </FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px; margin-left:13%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(i) to include any prospectus required by Section&nbsp;10(a)(3) of
the Securities Act; </FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px; margin-left:13%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(ii) to reflect in the prospectus any facts or events arising after the effective date of this
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 this 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 a 20 percent change in the maximum aggregate offering price set forth in the &#147;Calculation of
Registration Fee&#148; table in the effective registration statement; </FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px; margin-left:13%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(iii) to include any material information with respect
to the plan of distribution not previously disclosed in this Registration Statement or any material change to such information in this Registration Statement; </FONT></P> <P STYLE="margin-top:6px;margin-bottom:0px; margin-left:13%"><FONT
STYLE="font-family:Times New Roman" SIZE="2"><I>Provided, 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&nbsp;13 or Section&nbsp;15(d) of the Exchange Act that are incorporated by reference in this Registration Statement. </FONT></P>
<P STYLE="margin-top:6px;margin-bottom:0px; margin-left:8%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(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. </FONT></P>
<P STYLE="margin-top:6px;margin-bottom:0px; margin-left:8%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(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. </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(b) The undersigned Registrant hereby undertakes that, for purposes of determining any liability
under the Securities Act, each filing of the Registrant&#146;s annual report pursuant to Section&nbsp;13(a) or Section&nbsp;15(d) of the Exchange Act (and, where applicable, each filing of an employee benefit plan&#146;s annual report pursuant to
Section&nbsp;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. </FONT></P>
 <p STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">5 </FONT></P>


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 <P STYLE="margin-top:0px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">(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 Securities and Exchange Commission such indemnification is
against public policy as expressed in the Securities 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 Securities Act and will be
governed by the final adjudication of such issue. </FONT></P>
 <p STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">6 </FONT></P>


<p Style='page-break-before:always'>
<HR  SIZE="3" style="COLOR:#999999" WIDTH="100%" ALIGN="CENTER">

 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>SIGNATURES </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT
STYLE="font-family:Times New Roman" SIZE="2">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 of the requirements for filing on Form <FONT
STYLE="white-space:nowrap">S-8</FONT> and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of San Diego, State of California, on August&nbsp;5, 2013. </FONT></P>
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P><DIV ALIGN="right">
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="40%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE">


<TR>
<TD WIDTH="6%"></TD>
<TD VALIGN="bottom" WIDTH="2%"></TD>
<TD WIDTH="92%"></TD></TR>


<TR>
<TD VALIGN="top" COLSPAN="3"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>Mast Therapeutics, Inc.</B></FONT></TD></TR>
<TR>
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">By:</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:1px;border-bottom:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">/s/ Brian M. Culley</FONT></P></TD></TR>
<TR>
<TD VALIGN="top" COLSPAN="3"><FONT STYLE="font-family:Times New Roman" SIZE="2">Brian M. Culley</FONT></TD></TR>
<TR>
<TD VALIGN="top" COLSPAN="3"><FONT STYLE="font-family:Times New Roman" SIZE="2">Chief Executive Officer</FONT></TD></TR>
</TABLE></DIV> <P STYLE="margin-top:18px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>POWER OF ATTORNEY </B></FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT
STYLE="font-family:Times New Roman" SIZE="2">KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Brian M. Culley, Patrick L. Keran and Brandi L. Roberts, and each of them acting
individually, as his or her true and lawful attorneys-in-fact and agents, each with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign: (1)&nbsp;this registration
statement on Form S-8 under the Securities Act, in connection with the registration under the Securities Act of shares of common stock of the Registrant to be issued in connection with the Mast Therapeutics, Inc. 2013 Omnibus Incentive Plan; and
(2)&nbsp;any one or more amendments to any part of the foregoing registration statement, including any post-effective amendments, or appendices or supplements that may be required to be filed under the Securities Act to keep such registration
statement effective or to terminate its effectiveness; and/or to file the same, with all exhibits thereto and other documents in connection therewith, with the SEC, granting unto said attorneys-in-fact and agents, 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 attorneys-in-fact and agents, or
any of them or their substitute or resubstitute, may lawfully do or cause to be done by virtue hereof. </FONT></P> <P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">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. </FONT></P> <P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
<TABLE CELLSPACING="0" CELLPADDING="0" WIDTH="100%" BORDER="0" STYLE="BORDER-COLLAPSE:COLLAPSE">


<TR>
<TD WIDTH="33%"></TD>
<TD VALIGN="bottom"></TD>
<TD></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="47%"></TD>
<TD VALIGN="bottom" WIDTH="1%"></TD>
<TD WIDTH="15%"></TD></TR>
<TR>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:33pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Signature</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:15pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Title</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:16pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Date</B></FONT></P></TD></TR>


<TR>
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:0px;border-bottom:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">/s/ Brian M. Culley</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Brian M. Culley</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:0px"><FONT STYLE="font-family:Times New Roman" SIZE="2">Chief Executive Officer and Director</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">(Principal Executive Officer)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">August 5, 2013</FONT></TD></TR>
<TR>
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:0px;border-bottom:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">/s/ Brandi L. Roberts</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Brandi L. Roberts</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:0px"><FONT STYLE="font-family:Times New Roman" SIZE="2">Chief Financial Officer and Senior Vice President</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">(Principal Financial and Accounting Officer)</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">August 5, 2013</FONT></TD></TR>
<TR>
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:0px;border-bottom:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">/s/ Jack Lief</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Jack Lief</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Chair of the Board</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">August 5, 2013</FONT></TD></TR>
<TR>
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:0px;border-bottom:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">/s/ Ted W. Love</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Ted W. Love</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Director</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">August 5, 2013</FONT></TD></TR>
<TR>
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:0px;border-bottom:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">/s/ David A. Ramsay</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">David A. Ramsay</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Director</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">August 5, 2013</FONT></TD></TR>
<TR>
<TD HEIGHT="16"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD>
<TD HEIGHT="16" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top"> <P STYLE="margin-top:0px;margin-bottom:0px;border-bottom:1px solid #000000"><FONT STYLE="font-family:Times New Roman" SIZE="2">/s/ Lewis J. Shuster</FONT></P> <P STYLE="margin-top:0px;margin-bottom:1px"><FONT
STYLE="font-family:Times New Roman" SIZE="2">Lewis J. Shuster</FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom"></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Director</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;</FONT></TD>
<TD VALIGN="top" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">August 5, 2013</FONT></TD></TR>
</TABLE>
 <p STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">7 </FONT></P>


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 <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2"><B>INDEX TO EXHIBITS </B></FONT></P>
<P STYLE="margin-top:12px;margin-bottom:0px; text-indent:4%"><FONT STYLE="font-family:Times New Roman" SIZE="2">The following documents are filed as exhibits to this registration statement: </FONT></P>
<P STYLE="font-size:12px;margin-top:0px;margin-bottom:0px">&nbsp;</P>
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<TR>
<TD></TD>
<TD VALIGN="bottom" WIDTH="5%"></TD>
<TD WIDTH="44%"></TD>
<TD VALIGN="bottom" WIDTH="4%"></TD>
<TD WIDTH="44%"></TD></TR>
<TR>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:39pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Exhibit&nbsp;No.</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:85pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Description of Document</B></FONT></P></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="bottom" NOWRAP ALIGN="center"> <P STYLE="border-bottom:1px solid #000000;width:94pt" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="1"><B>Incorporation by Reference</B></FONT></P></TD></TR>


<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;4.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Composite Amended and Restated Certificate of Incorporation, as amended, of the Registrant</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Registration Statement on Form S-1 on May 28, 2013 (SEC File No. 333-188870-13873232)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;4.2</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Certificate of Ownership and Merger, effective as of March 11, 2013</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on March 1, 2013 (SEC File No. 001-32157-13657723)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;4.3</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Amended and Restated Bylaws of the Registrant, effective as of March 11, 2013</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on March 1, 2013 (SEC File No. 001-32157-13657723)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;4.4</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of common stock certificate of the Registrant</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Annual Report on Form 10-K on March 19, 2013 (SEC File No. 001-32157-13702619)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">&nbsp;&nbsp;5.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Opinion of Sheppard, Mullin, Richter &amp; Hampton LLP</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">23.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Consent of PricewaterhouseCoopers LLP, Independent Registered Public Accounting Firm</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">23.2</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Consent of CohnReznick LLP, Independent Registered Public Accounting Firm</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">23.3</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Consent of Sheppard, Mullin, Richter &amp; Hampton LLP</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Included in Exhibit 5.1 filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">24.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Power of Attorney</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Included as part of the signature page to this Registration Statement</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.1</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Mast Therapeutics, Inc. 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.2</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of Non-Statutory Stock Option Grant Agreement&#151;Director (for grants to non-employee directors) under 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.3</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of Incentive Stock Option Grant Agreement (for grants to employees) under the 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.4</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of Non-Statutory Stock Option Grant Agreement (for grants to consultants) under the 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed herewith</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.5</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of Senior Executive Incentive Stock Option Grant Agreement (for grants to the Registrant&#146;s chief executive officer and president and chief operating officer) under the
2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
<TR>
<TD HEIGHT="8"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD>
<TD HEIGHT="8" COLSPAN="2"></TD></TR>
<TR>
<TD VALIGN="top" NOWRAP><FONT STYLE="font-family:Times New Roman" SIZE="2">99.6</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Form of CMO Incentive Stock Option Grant Agreement (for grants to the Registrant&#146;s chief medical officer) under the 2013 Omnibus Incentive Plan</FONT></TD>
<TD VALIGN="bottom"><FONT SIZE="1">&nbsp;&nbsp;</FONT></TD>
<TD VALIGN="top"><FONT STYLE="font-family:Times New Roman" SIZE="2">Filed with the Registrant&#146;s Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)</FONT></TD></TR>
</TABLE>
 <p STYLE="margin-top:0px;margin-bottom:0px"><FONT SIZE="1">&nbsp;</FONT></P> <P STYLE="margin-top:0px;margin-bottom:0px" ALIGN="center"><FONT STYLE="font-family:Times New Roman" SIZE="2">8 </FONT></P>

</BODY></HTML>
[{"type": "S-8", "sequence": "1", "filename": "d576861ds8.htm", "description": "FORM S-8", "secsgml_size_bytes": 74452}]
{"company-data": {"conformed-name": "Mast Therapeutics, Inc.", "cik": "0001160308", "assigned-sic": "2834", "irs-number": "841318182", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-190376", "film-number": "131010528"}, "business-address": {"street1": "12390 EL CAMINO REAL", "street2": "SUITE 150", "city": "SAN DIEGO", "state": "CA", "zip": "92130", "phone": "8585520866"}, "mail-address": {"street1": "12390 EL CAMINO REAL", "street2": "SUITE 150", "city": "SAN DIEGO", "state": "CA", "zip": "92130"}, "former-company": [{"former-conformed-name": "ADVENTRX PHARMACEUTICALS INC", "date-changed": "20030613"}, {"former-conformed-name": "BIOKEYS PHARMACEUTICALS INC", "date-changed": "20010928"}]}
FORM S-8
As Filed with the Securities and Exchange Commission on August 5, 2013
Registration No. 333-
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM
S-8
REGISTRATION STATEMENT
UNDER
THE SECURITIES ACT OF 1933
Mast
Therapeutics, Inc.
(Exact name of registrant as specified in its charter)
Delaware
84-1318182
(State or other jurisdiction of
incorporation or organization)
(I.R.S. Employer
Identification No.)
12390 El Camino Real, Suite 150
San Diego, California
92130
(Address of Principal Executive Offices)
(Zip Code)
Mast Therapeutics, Inc. 2013 Omnibus Incentive Plan
(Full title of the plans)
Patrick L.
Keran
President and Chief Operating Officer
Mast Therapeutics, Inc.
12390 El Camino Real, Suite 150
San Diego, California, 92130
(Name and Address of Agent For Service)
(858) 552-0866
(Telephone number, including area code, of agent for service)
Copies to:
Kirt W. Shuldberg, Esq.
Sheppard, Mullin, Richter & Hampton LLP
12275 El Camino Real, Suite 200
San Diego, California 92130
(858) 720-8900
Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of "large accelerated
filer," "accelerated filer," and "smaller reporting company" in Rule 12b-2 of the Exchange Act. (Check one):
Large Accelerated filer
¨
Accelerated filer
¨
Non-accelerated filer
¨
(Do not check if a smaller reporting company)
Smaller reporting company
x
CALCULATION OF REGISTRATION FEE
Title of Securities to be Registered
Amount to be
Registered (1)
Proposed Maximum
Offering Price
Per Share
Proposed Maximum
Aggregate Offering
Price
Amount of
Registration Fee
Common Stock, par value $0.001 per share: To be issued under the Mast Therapeutics, Inc.
2013 Omnibus Incentive Plan (2)
10,556,050 shares
$0.46(3)
$4,855,783(3)
$663
(1)
Pursuant to Rule 416 under the Securities Act of 1933, as amended (the "Securities Act"), this Registration Statement shall also cover any additional shares
of common stock that may become issuable under the Mast Therapeutics, Inc. 2013 2008 Omnibus Incentive Plan (the "2013 Plan") by reason of any stock split, stock dividend, recapitalization, or any other similar transaction effected without
receipt of consideration that results in an increase in the Registrant's outstanding shares of common stock.
(2)
Represents (i) 6,539,207 shares of the Registrant's common stock that became available for issuance on June 19, 2013 under the 2013 Plan, (ii) 4,016,843 shares
that may be added to the 2013 Plan upon the forfeiture, expiration or cash settlement of outstanding awards granted under the Registrant's Amended and Restated 2008 Omnibus Incentive Plan, 2008 Omnibus Incentive Plan, and 2005 Equity Incentive
Plan (the "Prior Plans"). As of June 19, 2013, no new awards may be granted under any of the Prior Plans.
(3)
Estimated pursuant to Rules 457(c) and 457(h) under the Securities Act solely for the purpose of calculating the registration fee, based on the average of the high and
low prices of the Registrant's common stock on the NYSE MKT equities market on July 30, 2013.
The Registration
Statement shall become effective upon filing in accordance with Rule 462(a) under the Securities Act.
PART I
INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS
Item 1.
Plan Information.*
Item 2.
Registrant Information and Employee Plan Annual Information.*
*
The documents containing the information specified in "Item 1. Plan Information" and "Item 2. Registrant Information and Employee Plan Annual
Information" of Form S-8 will be sent or given to participants of the 2013 Plan, as specified by Rule 428(b)(1) under the Securities Act. Such documents are not required to be, and are not, filed with the Securities and Exchange Commission (the
"SEC") either as part of this Registration Statement or as a prospectus or prospectus supplement pursuant to Rule 424 under the Securities Act. These documents and the documents incorporated by reference in this Registration Statement
pursuant to Item 3 of Part II of Form S-8, taken together, constitute a prospectus that meets the requirements of Section 10(a) of the Securities Act.
PART II
INFORMATION REQUIRED IN REGISTRATION STATEMENT
Item 3.
Incorporation of Documents by Reference.
The SEC allows the Registrant to "incorporate by reference" information contained in documents that the Registrant files with the SEC. This means that the Registrant can disclose important
information to you by referring you to those documents and that the information in this Registration Statement is not complete. You should read the information incorporated by reference for more detail. The Registrant incorporates by reference in
two ways. First, the Registrant incorporates by reference by listing below certain documents that the Registrant has already filed with the SEC. The information in these documents is considered part of this Registration Statement. Second, the
information in documents that the Registrant files in the future will update and supersede the information currently in, and be incorporated by reference in, this Registration Statement.
The Registrant incorporates by reference into this Registration Statement the documents listed below and any filings it makes with the
SEC pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), after the date of this Registration Statement until the filing of a post-effective amendment that terminates
this offering (in each case, except for the information furnished under Item 2.02 or Item 7.01 in any current report on Form 8-K or amendment to such current report):
(a)
The Registrant's Annual Report on Form 10-K for the fiscal year ended December 31, 2012, filed with the SEC on March 19, 2013, including all material
incorporated by reference therein;
(b)
The Registrant's Quarterly Reports on Form 10-Q for the quarters ended March 31, 2013 and June 30, 2013, filed with the SEC on May 15, 2013 and
August 5, 2013, respectively, including all material incorporated by reference therein;
(c)
The Registrant's Current Reports on Form 8-K filed on January 3, 2013, February 8, 2013, February 26, 2013, March 1,
2013, March 12, 2013, June 17, 2013 and June 21, 2013, including all material incorporated by reference therein; and
(d)
The description of the Registrant's common stock contained in the Registrant's Registration Statement on
Form 8-A
filed with the SEC on April 27, 2004, pursuant to Section 12(b) of the Exchange Act, including any amendments or reports filed for the purpose of updating such descriptions.
2
Any statement contained in a document incorporated or deemed to be incorporated by reference
herein shall be deemed to be modified or superseded for the purposes of this Registration Statement to the extent that a statement contained herein or in any other subsequently filed document which also is or deemed to be incorporated by reference
herein modifies or supersedes such statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a 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 authorizes a corporation to indemnify its directors and officers against liabilities arising out of actions, suits and proceedings to which they
are made or threatened to be made a party by reason of the fact of their prior or current service to the corporation as a director or officer, in accordance with the provisions of Section 145, which are sufficiently broad to permit
indemnification under certain circumstances for liabilities arising under the Securities Act. The indemnity may cover expenses (including attorneys' fees) judgments, fines and amounts paid in settlement actually and reasonably incurred by the
director or officer in connection with any such action, suit or proceeding. Section 145 permits corporations to pay expenses (including attorneys' fees) incurred by directors and officers in advance of the final disposition of such action,
suit or proceeding. In addition, Section 145 provides that a corporation has the power to purchase and maintain insurance on behalf of its directors and officers against any liability asserted against them and incurred by them in their capacity
as a director or officer, or arising out of their status as such, whether or not the corporation would have the power to indemnify the director or officer against such liability under Section 145.
The Registrant's amended and restated certificate of incorporation, as amended (the "Certificate of Incorporation")
provides that, to the fullest extent permitted by the Delaware General Corporation Law, (1) a director shall not be personally liable to the Registrant or its stockholders for monetary damages for breach of fiduciary duty as a director, and
(2) the Registrant shall indemnify any director or officer made a party to an action or proceeding, whether criminal, civil, administrative or investigative, by reason of the fact of such person's current or prior service as a director or
officer of the Registrant, any predecessor of the Registrant or any other enterprise per the Registrant's or any predecessor to the Registrant's request.
The Registrant amended and restated bylaws (the "Bylaws"), provide that (a) the Registrant shall indemnify its directors and officers to the maximum extent and in the manner permitted by
the Delaware General Corporation Law against expenses (including attorneys' fees), judgments, fines, ERISA excise taxes, settlements and other amounts actually and reasonably incurred in connection with any proceeding, whether civil, criminal,
administrative or investigative, arising by reason of the fact that such person is or was an agent of the corporation, subject to certain limited exceptions, (b) the Registrant shall advance expenses incurred by any director or officer prior to
the final disposition of any proceeding to which the director or officer was or is or is threatened to be made a party promptly following a request therefore, subject to certain limited exceptions, and (c) the rights conferred in the Bylaws are
not exclusive.
The Registrant has entered into indemnification agreements with each of its directors and executive officers
to give such directors and officers additional contractual assurances regarding the scope of the indemnification set forth in the Certificate of Incorporation and the Bylaws and to provide additional procedural protections. These agreements, among
other things, provide that the Registrant will indemnify its directors and executive officers for expenses (including attorneys' fees), judgments, fines, penalties and amounts paid in settlement (including all interest, assessments and other
charges paid or payable in connection therewith) actually and reasonably incurred by a director or executive officer in connection with any action or proceeding to which such person was, is or is threatened to be made a party, a witness or other
participant by reason of such person's services as a director or executive officer of the Registrant, any of the Registrant's subsidiaries or any other company or enterprise to which the person provides services at the Registrant's
request, and any federal, state, local or foreign taxes imposed on the director or executive officer as a result of the actual or deemed receipt of any payments under the indemnification agreements. In addition, the indemnification agreements
provide that, upon the request of a director or executive officer, the Registrant shall advance expenses (including attorneys' fees) to the director or officer. The Registrant intends to enter into indemnification agreements with any new
directors and executive officers in the future.
3
The Registrant has also obtained insurance policies covering its directors and officers with
respect to certain liabilities, including liabilities arising under the Securities Act.
Item 7.
Exemption From Registration Claimed.
Not applicable.
Item 8.
Exhibits.
Exhibit No.
Description of Document
Incorporation by Reference
4.1
Composite Amended and Restated Certificate of Incorporation, as amended, of the Registrant
Filed with the Registrant's Registration Statement on Form S-1 on May 28, 2013 (SEC File No. 333-188870-13873232)
4.2
Certificate of Ownership and Merger, effective as of March 11, 2013
Filed with the Registrant's Current Report on Form 8-K on March 1, 2013 (SEC File No. 001-32157-13657723)
4.3
Amended and Restated Bylaws of the Registrant, effective as of March 11, 2013
Filed with the Registrant's Current Report on Form 8-K on March 1, 2013 (SEC File No. 001-32157-13657723)
4.4
Form of common stock certificate of the Registrant
Filed with the Registrant's Annual Report on Form 10-K on March 19, 2013 (SEC File No. 001-32157-13702619)
5.1
Opinion of Sheppard, Mullin, Richter & Hampton LLP
Filed herewith
23.1
Consent of PricewaterhouseCoopers LLP, Independent Registered Public Accounting Firm
Filed herewith
23.2
Consent of CohnReznick LLP, Independent Registered Public Accounting Firm
Filed herewith
23.3
Consent of Sheppard, Mullin, Richter & Hampton LLP
Included in Exhibit 5.1 filed herewith
24.1
Power of Attorney
Included as part of the signature page to this Registration Statement
99.1
Mast Therapeutics, Inc. 2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
99.2
Form of Non-Statutory Stock Option Grant Agreement—Director (for grants to non-employee directors) under 2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
99.3
Form of Incentive Stock Option Grant Agreement (for grants to employees) under the 2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
99.4
Form of Non-Statutory Stock Option Grant Agreement (for grants to consultants) under the 2013 Omnibus Incentive Plan
Filed herewith
99.5
Form of Senior Executive Incentive Stock Option Grant Agreement (for grants to the Registrant's chief executive officer and president and chief operating officer) under the
2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
99.6
Form of CMO Incentive Stock Option Grant Agreement (for grants to the Registrant's chief medical officer) under the 2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
4
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;
(ii) to reflect in the prospectus any facts or events arising after the effective date of this
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 this 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 a 20 percent change in the maximum aggregate offering price set forth in the "Calculation of
Registration Fee" table in the effective registration statement;
(iii) to include any material information with respect
to the plan of distribution not previously disclosed in this Registration Statement or any material change to such information in this Registration Statement;
Provided, 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 Exchange Act that are incorporated by reference in this 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.
(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.
5
(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 Securities and Exchange Commission such indemnification is
against public policy as expressed in the Securities 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 Securities Act and will be
governed by the final adjudication of such issue.
6
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 of 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 the City of San Diego, State of California, on August 5, 2013.
Mast Therapeutics, Inc.
By:
/s/ Brian M. Culley
Brian M. Culley
Chief Executive Officer
POWER OF ATTORNEY
KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature appears below hereby constitutes and appoints Brian M. Culley, Patrick L. Keran and Brandi L. Roberts, and each of them acting
individually, as his or her true and lawful attorneys-in-fact and agents, each with full power of substitution and resubstitution, for him or her and in his or her name, place and stead, in any and all capacities, to sign: (1) this registration
statement on Form S-8 under the Securities Act, in connection with the registration under the Securities Act of shares of common stock of the Registrant to be issued in connection with the Mast Therapeutics, Inc. 2013 Omnibus Incentive Plan; and
(2) any one or more amendments to any part of the foregoing registration statement, including any post-effective amendments, or appendices or supplements that may be required to be filed under the Securities Act to keep such registration
statement effective or to terminate its effectiveness; and/or to file the same, with all exhibits thereto and other documents in connection therewith, with the SEC, granting unto said attorneys-in-fact and agents, 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 attorneys-in-fact and agents, or
any of them or their substitute or resubstitute, may lawfully do or cause to be done by virtue hereof.
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/ Brian M. Culley
Brian M. Culley
Chief Executive Officer and Director
(Principal Executive Officer)
August 5, 2013
/s/ Brandi L. Roberts
Brandi L. Roberts
Chief Financial Officer and Senior Vice President
(Principal Financial and Accounting Officer)
August 5, 2013
/s/ Jack Lief
Jack Lief
Chair of the Board
August 5, 2013
/s/ Ted W. Love
Ted W. Love
Director
August 5, 2013
/s/ David A. Ramsay
David A. Ramsay
Director
August 5, 2013
/s/ Lewis J. Shuster
Lewis J. Shuster
Director
August 5, 2013
7
INDEX TO EXHIBITS
The following documents are filed as exhibits to this registration statement:
Exhibit No.
Description of Document
Incorporation by Reference
4.1
Composite Amended and Restated Certificate of Incorporation, as amended, of the Registrant
Filed with the Registrant's Registration Statement on Form S-1 on May 28, 2013 (SEC File No. 333-188870-13873232)
4.2
Certificate of Ownership and Merger, effective as of March 11, 2013
Filed with the Registrant's Current Report on Form 8-K on March 1, 2013 (SEC File No. 001-32157-13657723)
4.3
Amended and Restated Bylaws of the Registrant, effective as of March 11, 2013
Filed with the Registrant's Current Report on Form 8-K on March 1, 2013 (SEC File No. 001-32157-13657723)
4.4
Form of common stock certificate of the Registrant
Filed with the Registrant's Annual Report on Form 10-K on March 19, 2013 (SEC File No. 001-32157-13702619)
5.1
Opinion of Sheppard, Mullin, Richter & Hampton LLP
Filed herewith
23.1
Consent of PricewaterhouseCoopers LLP, Independent Registered Public Accounting Firm
Filed herewith
23.2
Consent of CohnReznick LLP, Independent Registered Public Accounting Firm
Filed herewith
23.3
Consent of Sheppard, Mullin, Richter & Hampton LLP
Included in Exhibit 5.1 filed herewith
24.1
Power of Attorney
Included as part of the signature page to this Registration Statement
99.1
Mast Therapeutics, Inc. 2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
99.2
Form of Non-Statutory Stock Option Grant Agreement—Director (for grants to non-employee directors) under 2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
99.3
Form of Incentive Stock Option Grant Agreement (for grants to employees) under the 2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
99.4
Form of Non-Statutory Stock Option Grant Agreement (for grants to consultants) under the 2013 Omnibus Incentive Plan
Filed herewith
99.5
Form of Senior Executive Incentive Stock Option Grant Agreement (for grants to the Registrant's chief executive officer and president and chief operating officer) under the
2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
99.6
Form of CMO Incentive Stock Option Grant Agreement (for grants to the Registrant's chief medical officer) under the 2013 Omnibus Incentive Plan
Filed with the Registrant's Current Report on Form 8-K on June 21, 2013 (SEC File No. 001-32157-13927320)
8