Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
QVT Associates GP LLC
   2. Issuer Name and Ticker or Trading Symbol
ACHILLION PHARMACEUTICALS INC [ACHN] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
1177 AVENUE OF THE AMERICAS, 9TH FLOOR		 3. Date of Earliest Transaction (Month/Day/Year)
07/02/2013
(Street)

NEW YORK, NY 10036		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
___ Form filed by One Reporting Person
_X_ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock, $0.001 par value 07/02/2013   P   50,000 A $ 6.31 11,017,853 I Through QVT Fund IV LP, QVT Fund V LP and Quintessence Fund L.P.
Common Stock, $0.001 par value 07/02/2013   P   150,000 A $ 6.3 11,167,853 I Through QVT Fund IV LP, QVT Fund V LP and Quintessence Fund L.P.
Common Stock, $0.001 par value 07/02/2013   P   1,300,000 A $ 6.51 12,467,853 I Through QVT Fund IV LP, QVT Fund V LP and Quintessence Fund L.P.
Common Stock, $0.001 par value 07/03/2013   P   20,511 A $ 6.32 12,488,364 I Through QVT Fund IV LP, QVT Fund V LP and Quintessence Fund L.P.
Common Stock, $0.001 par value 07/03/2013   P   442,737 A $ 6.24 12,931,101 I Through QVT Fund IV LP, QVT Fund V LP and Quintessence Fund L.P.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
QVT Associates GP LLC
1177 AVENUE OF THE AMERICAS
9TH FLOOR
NEW YORK, NY 10036		     X    
QVT Fund V LP
1177 AVENUE OF THE AMERICAS
9TH FLOOR
NEW YORK, NY 10036		     X    

Signatures

 /s/ Tracy Fu, Managing Member   07/05/2013
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
 
Remarks:
On July 2, 2013, QVT Fund IV LP purchased 189,331 shares of Common Stock, QVT Fund V LP purchased 1,147,422 shares of Common Stock and Quintessence Fund L.P. purchased 163,247 shares of Common Stock. On July 3, 2013, QVT Fund IV LP purchased 58,470 shares of Common Stock, QVT Fund V LP purchased 354,361 shares of Common Stock and Quintessence Fund L.P. purchased 50,417 shares of Common Stock. As a result, QVT Fund IV LP directly beneficially owns 1,664,220 shares of Common Stock, QVT Fund V LP directly beneficially owns 9,831,194 shares of Common Stock and Quintessence Fund L.P. directly beneficially owns 1,435,687 shares of Common Stock. QVT Associates GP LLC is the general partner of QVT Fund IV LP, QVT Fund V LP and Quintessence Fund L.P. (together with QVT Fund IV LP, and QVT Fund V LP, the "Funds"). QVT Financial LP is the investment manager for the Funds and therefore may be deemed the beneficial owner of the Common Stock held by the Funds. QVT Financial GP LLC is the general partner of QVT Financial LP and therefore may be deemed the beneficial owner of Common Stock beneficially owned by QVT Financial LP. The reporting person disclaims beneficial ownership of the reported securities except to the extent of its pecuniary interest therein.

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