SHAREHOLDER ALERT: Investors With More Than $150,000 In Losses From Investments In Achillion Pharmaceuticals, Inc. Are Encouraged To Contact Wolf Haldenstein Before The December 9, 2013 Lead Plaintiff Deadline

On October 23, 2013, Wolf Haldenstein Adler Freeman & Herz LLP filed a class action lawsuit in the United States District Court on behalf of all persons who purchased or otherwise acquired common stock of Achillion Pharmaceuticals, Inc. (“Achillion” or the “Company”) [NASDAQ GS: ACHN] between August 8, 2012 and September 30, 2013, inclusive (the “Class Period”), against the Company and certain of the Company’s officers, alleging securities fraud pursuant to the Securities Exchange Act of 1934.

The litigation is styled Jiang v. Achillion Pharmaceuticals, Inc. A copy of the Complaint can be viewed on the Wolf Haldenstein website at www.whafh.com.

The Complaint alleges that during the Class Period, Achillion engaged in a fraudulent scheme to artificially inflate the Company’s stock price by disseminating false and misleading statements concerning its clinical trials of the drug sovaprevir. The Company falsely represented that sovaprevir, one of the protease inhibitor compounds intended as a treatment for the hepatitis C virus, was well-tolerated and had a low potential for drug-drug interactions. Indeed, Achillion touted the results of its clinical tests even though, in July 2013, the United States Food and Drug Administration (“FDA”) placed a clinical hold on sovaprevir.

Despite the Company’s repeated assurances, on September 27, 2013, Achillion announced that the FDA ultimately concluded that the removal of the clinical hold was not warranted. On this news, shares of Achillion fell 59.53% on intraday trading, to $2.94 per share on September 30, 2013.

If you purchased ACHN common stock during the Class Period, you may request that the Court appoint you as lead plaintiff by December 9, 2013. A lead plaintiff is a representative party that acts on behalf of other class members in directing the litigation.

Wolf Haldenstein has represented individual and institutional investors for many years, serving as lead counsel in numerous cases in United States federal and state courts. If you wish to discuss this action or have any questions, please contact Wolf Haldenstein Adler Freeman & Herz LLP at 270 Madison Avenue, New York, New York 10016, by telephone at (800) 575-0735 (Gregory M. Nespole, Esq.), via e-mail at classmember@whafh.com, or visit our website at www.whafh.com. All e-mail correspondence should make reference to “Achillion”.

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