Wolf Haldenstein Adler Freeman & Herz LLP Commences Class Action Lawsuit on Behalf of Achillion Pharmaceuticals, Inc. Investors

  Wolf Haldenstein Adler Freeman & Herz LLP Commences Class Action Lawsuit on
  Behalf of Achillion Pharmaceuticals, Inc. Investors

Business Wire

NEW YORK -- October 24, 2013

Wolf Haldenstein Adler Freeman & Herz LLP announces that a class action
lawsuit has been filed in the United States District Court, District of
Connecticut, 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
(“Defendants”), alleging securities fraud pursuant to Sections 10(b) and 20(a)
of the Securities Exchange Act of 1934 [15 U.S.C. §§ 78j(b) and 78t(a)] and
Rule 10b-5 promulgated thereunder by the SEC [17 C.F.R. § 240.10b-5].

The litigation is styled Jiang v. Achillion Pharmaceuticals, Inc., C.A. No.
3:13-cv-01543. A copy of the Complaint filed in this action is available from
the Court, or can be viewed on the Wolf Haldenstein Adler Freeman & Herz LLP
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 materially false and misleading statements concerning its
clinical trials of the drug sovaprevir. The Company falsely represented that
sovaprevir, one of the protease inhibitor compounds in its portfolio of oral
treatments 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 after elevations
in liver enzymes were noted in a phase 1 interaction study.

As recently as September 10, 2013, while the FDA’s clinical hold was still in
place, the Company’s CEO, Milind S. Deshpande, stated in an investor
presentation that Achillion would likely “receive a favorable response from
the [FDA]” and projected, with a “99.99% confidence interval,” that there
would be “no overlap between the exposures … with [] clinical doses versus the
exposure … in the [drug-drug interaction] study.” 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 $4.30 per share, more than 59.53% on
intraday trading, to $2.94 per share on September 30, 2013.

The suit alleges that in ignorance of the false and misleading nature of the
statements described in the Complaint, and the deceptive and manipulative
devices and contrivances employed by said Defendants, Plaintiff and the other
members of the Class relied, to their detriment, on the integrity of the
market price of Achillion common stock. Had Plaintiff and the other members of
the Class known the truth, they would not have purchased said securities, or
would not have purchased them at the inflated prices that were paid.

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. In order to be appointed lead plaintiff, the
Court must determine that the class member’s claim is typical of the claims of
other class members, and that the class member will adequately represent the
class. Under certain circumstances, one or more class members may together
serve as “lead plaintiff.” Your ability to share in any recovery is not,
however, affected by the decision whether or not to serve as a lead plaintiff.
You may retain Wolf Haldenstein, or other counsel of your choice, to serve as
your counsel in this action.

Wolf Haldenstein has extensive experience in the prosecution of securities
class actions and derivative litigation in state and federal trial and
appellate courts across the country. The firm has approximately 70 attorneys
in various practice areas; and offices in Chicago, New York City, and San
Diego. The reputation and expertise of this firm in shareholder and other
class litigation has been repeatedly recognized by the courts, which have
appointed it to major positions in complex securities multi-district and
consolidated litigation.

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”.

Contact:

Wolf Haldenstein Adler Freeman & Herz LLP
Gregory M. Nespole, Esq., 800-575-0735
classmember@whafh.com