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<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 12pt 0 0; text-align: center"><B>UNITED STATES<BR>
SECURITIES AND EXCHANGE COMMISSION</B></P>

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

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

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

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

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

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

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

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center">Date of Report (Date of earliest event reported):
February 21, 2012</P>

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

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

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

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 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: 34%; padding-right: 5.4pt; padding-left: 5.4pt; font-size: 10pt; font-weight: bold; text-align: center">Delaware</TD>
    <TD STYLE="width: 39%; padding-right: 5.4pt; padding-left: 5.4pt; font-size: 10pt; font-weight: bold; text-align: center">001&#45;32979</TD>
    <TD STYLE="width: 27%; padding-right: 5.4pt; padding-left: 5.4pt; font-size: 10pt; font-weight: bold; text-align: center">94&#45;3409596</TD></TR>
<TR STYLE="vertical-align: top">
    <TD STYLE="padding-right: 5.4pt; padding-left: 5.4pt">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 4.5pt; text-align: center"><B>(State or other jurisdiction
        of incorporation)</B></P></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 STYLE="padding-right: 5.4pt; padding-left: 5.4pt">
        <P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: center"><B>(IRS Employer Identification
        No.)</B></P></TD></TR>
</TABLE>
<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0 0 1.25in">&nbsp;</P>

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

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

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

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

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

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

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

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

<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: 0in"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings 2">&#163;</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: 0in"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings 2">&#163;</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>

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<TD STYLE="width: 0in"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings 2">&#163;</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>

<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: 0in"></TD><TD STYLE="width: 0.25in; text-align: left"><FONT STYLE="font-family: Wingdings 2">&#163;</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: 0">&nbsp;</P>

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<TD STYLE="width: 0in"></TD><TD STYLE="width: 1in; text-align: left"><B>Item 8.01</B></TD><TD STYLE="text-align: justify"><B>Other Events.</B></TD>
</TR></TABLE>

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">On February 21, 2012, Threshold Pharmaceuticals, Inc. issued a press
release announcing <FONT STYLE="color: black">clinical trial results </FONT>of the Phase 2b study <FONT STYLE="color: black">evaluating
the efficacy and safety of two doses of the investigational agent TH-302 in combination with gemcitabine compared to gemcitabine
alone in patients with first-line advanced pancreatic cancer.</FONT> The press release is attached as Exhibit 99.1 to this Form
8-K.</P>

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<TD STYLE="width: 0in"></TD><TD STYLE="width: 1in; text-align: left"><B>Item 9.01</B></TD><TD STYLE="text-align: justify"><B>Financial Statements and Exhibits.</B></TD>
</TR></TABLE>

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

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<TD STYLE="width: 0.5in"></TD><TD STYLE="width: 0.5in; text-align: left">(d)</TD><TD STYLE="text-align: justify">Exhibits</TD>
</TR></TABLE>

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

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<TD STYLE="width: 1in"></TD><TD STYLE="width: 1in; text-align: left">Exhibit 99.1</TD><TD STYLE="text-align: justify">Press release dated February 21, 2012.</TD>
</TR></TABLE>

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

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

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

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

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

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0; text-align: justify"></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">&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/ <FONT STYLE="font-variant: small-caps">Joel
A. Fernandes</FONT></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">&nbsp;</P>


<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">Date: February 21, 2012</P>

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

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

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

<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: 0in"></TD><TD STYLE="width: 1in; text-align: left"><U>Exhibit No.</U></TD><TD STYLE="text-align: justify"><U>Description</U></TD>
</TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0 0.85in 0 0">&nbsp;</P>

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<TD STYLE="width: 0in"></TD><TD STYLE="width: 1in; text-align: left">Exhibit 99.1</TD><TD STYLE="text-align: justify">Press release dated February 21, 2012.</TD>
</TR></TABLE>

<P STYLE="font: 10pt Times New Roman, Times, Serif; margin: 0">&nbsp;</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):
February 21, 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 February 21, 2012, Threshold Pharmaceuticals, Inc. issued a press
release announcing
clinical trial results
of the Phase 2b study
evaluating
the efficacy and safety of two doses of the investigational agent TH-302 in combination with gemcitabine compared to gemcitabine
alone in patients with first-line advanced pancreatic cancer.
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 February 21, 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: February 21, 2012
Exhibit Index
Exhibit No.
Description
Exhibit 99.1
Press release dated February 21, 2012.