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<P STYLE="margin-top:3pt; margin-bottom:0pt; font-size:14pt; font-family:Times New Roman" ALIGN="center"><B>SECURITIES AND EXCHANGE COMMISSION </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:14pt; font-family:Times New Roman" ALIGN="center"><B>WASHINGTON, D.C. 20549 </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
<P STYLE="line-height:1.0pt;margin-top:0pt;margin-bottom:2pt;border-bottom:1.00pt solid #000000">&nbsp;</P> <P STYLE="margin-top:8pt; margin-bottom:0pt; font-size:18pt; font-family:Times New Roman" ALIGN="center"><B>FORM 8-K </B></P>
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<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>CURRENT REPORT </B></P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Pursuant
to Section&nbsp;13 or 15(d) of the </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Securities Exchange Act of 1934 </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Date of Report (Date of earliest event reported): October&nbsp;8, 2013 </B><B> </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:24pt; font-family:Times New Roman" ALIGN="center"><B>Achillion Pharmaceuticals, Inc. </B></P>
<P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Exact name of registrant as specified in its charter) </B></P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD VALIGN="bottom" ALIGN="center"><B>Delaware</B></TD>
<TD VALIGN="bottom">&nbsp;</TD>
<TD VALIGN="bottom" ALIGN="center"><B>001-33095</B></TD>
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<TD VALIGN="bottom" ALIGN="center"><B>52-2113479</B></TD></TR>


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<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(State or other jurisdiction</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>of incorporation)</B></P></TD>
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<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Commission</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>File Number)</B></P></TD>
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<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(IRS Employer</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>Identification No.)</B></P></TD></TR>
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<TD VALIGN="top" ALIGN="center"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>300 George Street</B></P>
<P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>New Haven, CT</B></P></TD>
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<TD VALIGN="bottom" ALIGN="center"><B>06511</B></TD></TR>
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<TD VALIGN="top" ALIGN="center"><B>(Address of principal executive offices)</B></TD>
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</TABLE> <P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>Registrant&#146;s telephone number, including area code: <U>(203)&nbsp;624-7000 </U> </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>N/A </B></P> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:8pt; font-family:Times New Roman" ALIGN="center"><B>(Former name or
former address, if changed since last report) </B></P> <P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Check the appropriate box if the Form 8-K is intended to simultaneously satisfy the
filing obligation of the registrant under any of the following provisions: </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT> Written communications
pursuant to Rule 425 under the Securities Act (17 CFR 230.425) </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT> Soliciting material pursuant to Rule
14a-12 under the Exchange Act (17 CFR 240.14a-12). </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT> Pre-commencement communications pursuant to Rule
14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) </P> <P STYLE="margin-top:6pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman"><FONT STYLE="FONT-FAMILY:WINGDINGS">&#168;</FONT> Pre-commencement communications pursuant to Rule
13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)). </P>

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<TD WIDTH="9%" VALIGN="top" ALIGN="left"><B>Item&nbsp;8.01.</B></TD>
<TD ALIGN="left" VALIGN="top"><B>Other Events </B></TD></TR></TABLE> <P STYLE="margin-top:6pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">On October&nbsp;8, 2013, a class action lawsuit was filed against
Achillion Pharmaceuticals, Inc. (the &#147;Company&#148;) and certain of its current and former officers in the United States District Court for the District of Connecticut, captioned <I>Sniezak v. Achillion Pharmaceuticals, Inc., et al.</I>,
No.&nbsp;3:13-cv-1479. The complaint purports to be brought on behalf of all persons and entities who purchased the Company&#146;s securities between April&nbsp;21, 2012 and September&nbsp;27, 2013. The complaint generally alleges that the Company
and certain of its current and former officers violated Sections 10(b) and/or 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder by making allegedly false and/or misleading statements, as well as failing to disclose
allegedly material facts relating to sovaprevir, the Company&#146;s clinical-stage drug candidate for the treatment of chronic hepatitis C viral infection, particularly that sovaprevir did not interact well with other drugs commonly administered to
treat hepatitis and/or HIV and posed a health risk to patients. The complaint seeks unspecified damages, interest, attorneys&#146; fees, and other costs. The Company denies any allegations of wrongdoing and intends to vigorously defend against this
lawsuit. However, there is no assurance that the Company will be successful in its defense or that insurance will be available or adequate to fund any settlement or judgment or the litigation costs of this action. Moreover, the Company is unable to
predict the outcome or reasonably estimate a range of possible loss at this time. </P>

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 <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman" ALIGN="center"><B>SIGNATURE </B></P>
<P STYLE="margin-top:12pt; margin-bottom:0pt; text-indent:4%; font-size:10pt; font-family:Times New Roman">Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on
its behalf by the undersigned hereunto duly authorized. </P> <P STYLE="font-size:12pt;margin-top:0pt;margin-bottom:0pt">&nbsp;</P>
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<TD VALIGN="top" COLSPAN="3"><B>ACHILLION PHARMACEUTICALS, INC.</B></TD></TR>
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<TD VALIGN="top">Date: October&nbsp;10, 2013</TD>
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<TD VALIGN="top" ALIGN="right">By:</TD>
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<TD VALIGN="top" STYLE="BORDER-BOTTOM:1px solid #000000">/s/ Mary Kay Fenton</TD></TR>
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<TD VALIGN="top"> <P STYLE="margin-top:0pt; margin-bottom:0pt; font-size:10pt; font-family:Times New Roman">Mary Kay Fenton</P> <P STYLE="margin-top:0pt; margin-bottom:1pt; font-size:10pt; font-family:Times New Roman">Chief Financial
Officer</P></TD></TR>
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Form 8-K
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): October 8, 2013
Achillion Pharmaceuticals, Inc.
(Exact name of registrant as specified in its charter)
Delaware
001-33095
52-2113479
(State or other jurisdiction
of incorporation)
(Commission
File Number)
(IRS Employer
Identification No.)
300 George Street
New Haven, CT
06511
(Address of principal executive offices)
(Zip Code)
Registrant's telephone number, including area code:
(203) 624-7000
N/A
(Former name or
former address, if changed since last report)
Check the appropriate box if the Form 8-K 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 October 8, 2013, a class action lawsuit was filed against
Achillion Pharmaceuticals, Inc. (the "Company") and certain of its current and former officers in the United States District Court for the District of Connecticut, captioned
Sniezak v. Achillion Pharmaceuticals, Inc., et al.
,
No. 3:13-cv-1479. The complaint purports to be brought on behalf of all persons and entities who purchased the Company's securities between April 21, 2012 and September 27, 2013. The complaint generally alleges that the Company
and certain of its current and former officers violated Sections 10(b) and/or 20(a) of the Securities Exchange Act of 1934 and Rule 10b-5 promulgated thereunder by making allegedly false and/or misleading statements, as well as failing to disclose
allegedly material facts relating to sovaprevir, the Company's clinical-stage drug candidate for the treatment of chronic hepatitis C viral infection, particularly that sovaprevir did not interact well with other drugs commonly administered to
treat hepatitis and/or HIV and posed a health risk to patients. The complaint seeks unspecified damages, interest, attorneys' fees, and other costs. The Company denies any allegations of wrongdoing and intends to vigorously defend against this
lawsuit. However, there is no assurance that the Company will be successful in its defense or that insurance will be available or adequate to fund any settlement or judgment or the litigation costs of this action. Moreover, the Company is unable to
predict the outcome or reasonably estimate a range of possible loss at this time.
SIGNATURE
Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on
its behalf by the undersigned hereunto duly authorized.
ACHILLION PHARMACEUTICALS, INC.
Date: October 10, 2013
By:
/s/ Mary Kay Fenton
Mary Kay Fenton
Chief Financial
Officer