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

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

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

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

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

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Pursuant to Section 13 or 15(d) of the
</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Securities Exchange Act of 1934</B></P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center">Date of Report (Date of earliest event reported):
June 4, 2012</P>

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

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

<P STYLE="font: 18pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>THRESHOLD PHARMACEUTICALS, INC.</B></P>

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Exact name of registrant as specified
in its charter)</B></P>

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; border-collapse: collapse; font-family: Times New Roman, Times, Serif">
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    <TD STYLE="width: 32%; padding-right: 5.4pt; padding-left: 5.4pt; font-size: 10pt; font-weight: bold; text-align: center; border-bottom: Black 1pt solid">Delaware</TD>
    <TD STYLE="width: 2%; padding-bottom: 1pt">&nbsp;</TD>
    <TD STYLE="width: 32%; padding-right: 5.4pt; padding-left: 5.4pt; font-size: 10pt; font-weight: bold; text-align: center; border-bottom: Black 1pt solid">001&#45;32979</TD>
    <TD STYLE="width: 2%; padding-bottom: 1pt">&nbsp;</TD>
    <TD STYLE="width: 32%; padding-right: 5.4pt; padding-left: 5.4pt; font-size: 10pt; font-weight: bold; text-align: center; border-bottom: Black 1pt solid">94&#45;3409596</TD></TR>
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    <TD STYLE="padding-right: 5.4pt; padding-left: 5.4pt">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 4.5pt; text-align: center"><B>(State or other jurisdiction</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>of incorporation)</B></P></TD>
    <TD>&nbsp;</TD>
    <TD STYLE="padding-right: 5.4pt; padding-left: 5.4pt; font-size: 10pt; font-weight: bold; text-align: center">(Commission File Number)</TD>
    <TD>&nbsp;</TD>
    <TD STYLE="padding-right: 5.4pt; padding-left: 5.4pt">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(IRS Employer</B></P>
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>Identification No.)</B></P></TD></TR>
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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 1.25in">&nbsp;</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>170 Harbor Way, Suite 300<BR>
South San Francisco, California 94080</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Address of principal executive offices)(Zip
Code)</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0 0pt 63pt; text-align: justify">&nbsp;</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(650) 474-8200</B></P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: center"><B>(Registrant&rsquo;s telephone number,
including area code)</B></P>

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">Check the appropriate box below if the Form 8-K filing is intended
to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:</P>

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

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<TD STYLE="width: 0"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings">&#168;</FONT></TD><TD STYLE="text-align: justify">Written communications pursuant to Rule 425 under the Securities
Act (17 CFR 230.425)</TD>
</TR></TABLE>

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<TD STYLE="width: 0"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings">&#168;</FONT></TD><TD STYLE="text-align: justify">Soliciting material pursuant to Rule 14a-12 under the Exchange
Act (17 CFR 240.14a-12)</TD>
</TR></TABLE>

<TABLE CELLPADDING="0" CELLSPACING="0" STYLE="font: 10pt Times New Roman, Times, Serif; margin-top: 0; margin-bottom: 6pt"><TR STYLE="vertical-align: top; text-align: justify">
<TD STYLE="width: 0"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings">&#168;</FONT></TD><TD STYLE="text-align: justify">Pre-commencement communications pursuant to Rule 14d-2(b)
under the Exchange Act (17 CFR 240.14d-2(b))</TD>
</TR></TABLE>

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<TD STYLE="width: 0"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings">&#168;</FONT></TD><TD STYLE="text-align: justify">Pre-commencement communications pursuant to Rule 13e-4(c)
under the Exchange Act (17 CFR 240.13e-4(c))</TD>
</TR></TABLE>

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

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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>Item 8.01&#9;Other Events.</B></P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">On June 4, 2012, Threshold Pharmaceuticals, Inc. issued a press
release announcing <FONT STYLE="color: black">details from two clinical posters featured at the </FONT>American Society of Clinical
Oncology Meeting in Chicago: a trial-in-progress presentation summarizing the design and status of the ongoing international Phase
3 study comparing TH-302 in combination with doxorubicin to single agent doxorubicin in patients with first-line soft tissue sarcoma
and a presentation of updated <FONT STYLE="color: black">results </FONT>from the Phase 1 study of TH-302 in patients with advanced
leukemias conducted at the MD Anderson Cancer Center in Houston, Texas. The press release is attached as Exhibit 99.1 to this Form
8-K.</P>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0"><B>Item 9.01&#9;Financial Statements and Exhibits.</B></P>

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

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-indent: 0.5in">Exhibit 99.1&#9;Press release dated June
4, 2012.</P>

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

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

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

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0; text-align: justify; text-indent: 0.5in">Pursuant to the requirements
of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned
thereunto duly authorized.</P>

<P STYLE="font: 10pt Times New Roman, Times, Serif; text-align: left; text-indent: 0; margin-top: 0pt; margin-bottom: 6pt">&nbsp;</P>

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<TR>
    <TD STYLE="vertical-align: top">&nbsp;</TD>
    <TD COLSPAN="2"><B>THRESHOLD PHARMACEUTICALS, INC.</B></TD></TR>
<TR>
    <TD STYLE="vertical-align: top">&nbsp;</TD>
    <TD COLSPAN="2">&nbsp;</TD></TR>
<TR>
    <TD STYLE="vertical-align: top; width: 50%">&nbsp;</TD>
    <TD STYLE="width: 4%">By:&nbsp;</TD>
    <TD STYLE="vertical-align: top; width: 46%">/s/ Joel A. Fernandes</TD></TR>
<TR>
    <TD STYLE="vertical-align: top">&nbsp;</TD>
    <TD>&nbsp;</TD>
    <TD STYLE="vertical-align: top; border-top: #000000 1px solid">Joel A. Fernandes
<BR>
Vice President, Finance and Controller</TD></TR>
</TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; text-align: left; text-indent: 0pt; margin-top: 0pt; margin-bottom: 6pt">Date:
June 5, 2012</P>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0pt 0">&nbsp;</P>

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

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

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

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

<TABLE CELLSPACING="0" CELLPADDING="0" STYLE="width: 100%; font: 10pt Times New Roman, Times, Serif; border-collapse: collapse">
<TR STYLE="vertical-align: top">
    <TD STYLE="width: 15%; padding: 0; border-bottom: Black 1pt solid; text-indent: 0">Exhibit
    No.</TD>
    <TD STYLE="width: 2%; padding: 0; text-indent: 0">&nbsp;</TD>
    <TD STYLE="width: 83%; padding: 0; border-bottom: Black 1pt solid; text-indent: 0">Description</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 0; text-indent: 0">&nbsp;</TD>
    <TD STYLE="padding: 0; text-indent: 0">&nbsp;</TD>
    <TD STYLE="padding: 0; text-indent: 0">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 0; text-indent: 0">&nbsp;</TD>
    <TD STYLE="padding: 0; text-indent: 0">&nbsp;</TD>
    <TD STYLE="padding: 0; text-indent: 0">&nbsp;</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding: 0; text-indent: 0">Exhibit 99.1</TD>
    <TD STYLE="padding: 0; text-indent: 0">&nbsp;</TD>
    <TD STYLE="padding: 0; text-indent: 0">Press release dated June 4, 2012.</TD></TR>
</TABLE>


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

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



<P STYLE="margin: 0"></P>

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UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
_______________
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934
Date of Report (Date of earliest event reported):
June 4, 2012
THRESHOLD PHARMACEUTICALS, INC.
(Exact name of registrant as specified
in its charter)
Delaware
001-32979
94-3409596
(State or other jurisdiction
of incorporation)
(Commission File Number)
(IRS Employer
Identification No.)
170 Harbor Way, Suite 300
South San Francisco, California 94080
(Address of principal executive offices)(Zip
Code)
(650) 474-8200
(Registrant's telephone number,
including area code)
Check the appropriate box below if the Form 8-K filing is intended
to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
¨
Written communications pursuant to Rule 425 under the Securities
Act (17 CFR 230.425)
¨
Soliciting material pursuant to Rule 14a-12 under the Exchange
Act (17 CFR 240.14a-12)
¨
Pre-commencement communications pursuant to Rule 14d-2(b)
under the Exchange Act (17 CFR 240.14d-2(b))
¨
Pre-commencement communications pursuant to Rule 13e-4(c)
under the Exchange Act (17 CFR 240.13e-4(c))
Item 8.01	Other Events.
On June 4, 2012, Threshold Pharmaceuticals, Inc. issued a press
release announcing
details from two clinical posters featured at the
American Society of Clinical
Oncology Meeting in Chicago: a trial-in-progress presentation summarizing the design and status of the ongoing international Phase
3 study comparing TH-302 in combination with doxorubicin to single agent doxorubicin in patients with first-line soft tissue sarcoma
and a presentation of updated
results
from the Phase 1 study of TH-302 in patients with advanced
leukemias conducted at the MD Anderson Cancer Center in Houston, Texas. The press release is attached as Exhibit 99.1 to this Form
8-K.
Item 9.01	Financial Statements and Exhibits.
(d) Exhibits
Exhibit 99.1	Press release dated June
4, 2012.
SIGNATURES
Pursuant to the requirements
of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned
thereunto duly authorized.
THRESHOLD PHARMACEUTICALS, INC.
By:
/s/ Joel A. Fernandes
Joel A. Fernandes
Vice President, Finance and Controller
Date:
June 5, 2012
Exhibit Index
Exhibit
    No.
Description
Exhibit 99.1
Press release dated June 4, 2012.