Sec Form 4 Filing - VITULLO NICOLE @ ACHILLION PHARMACEUTICALS INC - 2020-01-28

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 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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1. Name and Address of Reporting Person VITULLO NICOLE 2. Issuer Name and Ticker or Trading Symbol ACHILLION PHARMACEUTICALS INC [ ACHN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O DOMAIN ASSOCIATES, LLC, 202 CARNEGIE CENTER, SUITE 104 3. Date of Earliest Transaction (MM/DD/YY) 01/28/2020 (Street) PRINCETON, NJ08540 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 01/28/2020 D 36,431 D $ 6.3 ( 1 ) 0 D Common Stock 01/28/2020 D 3,393,382 D $ 6.3 ( 1 ) 0 I By Domain Partners VIII, L.P. ( 2 ) Common Stock 01/28/2020 D 25,159 D $ 6.3 ( 1 ) 0 I By DP VIII Associates, L.P. ( 2 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Stock Option (Right to Buy) $ 3.1 01/28/2020 D 50,000 ( 3 ) 12/16/2020 Common Stock 50,000 ( 3 ) 0 D Stock Option (Right to Buy) $ 7.59 01/28/2020 D 20,000 ( 3 ) 12/12/2021 Common Stock 20,000 ( 3 ) 0 D Stock Option (Right to Buy) $ 8.64 01/28/2020 D 20,000 ( 3 ) 12/18/2022 Common Stock 20,000 ( 3 ) 0 D Stock Option (Right to Buy) $ 3.02 01/28/2020 D 25,000 ( 3 ) 12/17/2023 Common Stock 25,000 ( 3 ) 0 D Stock Option (Right to Buy) $ 13.24 01/28/2020 D 25,000 ( 3 ) 12/02/2024 Common Stock 25,000 ( 3 ) 0 D Stock Option (Right to Buy) $ 7.54 01/28/2020 D 30,000 ( 3 ) 01/25/2026 Common Stock 30,000 ( 3 ) 0 D Stock Option (Right to Buy) $ 4.09 01/28/2020 D 30,000 ( 3 ) 01/19/2027 Common Stock 30,000 ( 3 ) 0 D Stock Option (Right to Buy) $ 2.9 01/28/2020 D 30,000 ( 3 ) 02/09/2028 Common Stock 30,000 ( 3 ) 0 D Stock Option (Right to Buy) $ 2.18 01/28/2020 D 42,000 ( 3 ) 01/23/2029 Common Stock 42,000 ( 3 ) 0 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other VITULLO NICOLE C/O DOMAIN ASSOCIATES, LLC 202 CARNEGIE CENTER, SUITE 104 PRINCETON, NJ08540 X Signatures /s/ Lisa A. Kraeutler, Attorney-in-Fact 01/29/2020 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Disposed of pursuant to the merger agreement (the "Merger Agreement") among Achillion Pharmaceuticals, Inc. ("Achillion"), Alexion Pharmaceuticals, Inc. ("Alexion") and Beagle Merger Sub, Inc. In addition to the cash consideration of $6.30 per share, each shareholder will also receive one contingent value right ("CVR") per share. Each CVR represents the right to receive contingent cash payments of $1.00 upon the achievement of a certain clinical trial milestone with respect to ACH-5228 and $1.00 upon the achievement of a certain regulatory approval milestone with respect to ACH-4471. ( 2 )The Reporting Person is a Managing Member of Domain Associates, LLC and a Managing Member of One Palmer Square Associates VIII, LLC, which is the sole general partner of Domain Partners VIII, L.P. and DP VIII Associates, L.P. Pursuant to Instruction 4(b)(iv) of Form 4, the Reporting Person has elected to report as indirectly beneficially owned the entire number of securities beneficially owned by each such entity. The Reporting Person disclaims b eneficial ownership of any securities, and any proceeds thereof, that exceed her pecuniary interest therein and/or that are not actually distributed to her. ( 3 )Subject to certain conditions, at the effective time, all unexercised options with an exercise price below $6.30 were cancelled and converted into the right to receive (i) a cash payment of (A) $6.30 less the exercise price, multiplied by (B) the number of shares subject thereto and (ii) one CVR per share subject thereto. Options with an exercise price of $6.30 or greater were cancelled and converted into the right to receive a cash payment with respect to each share subject thereto upon each milestone payment date equal to (i) the amount by which, as of the payment date, the sum of (x) $6.30, (y) the amount per share previously paid in respect of any earlier payment date and (z) the amount in cash to be paid at such payment date exceeds the exercise price payable under such option, less (ii) the amount of all payments previously received with respect to such option. Options with an exercise price of $8.30 or greater were cancelled without any consideration payable therefor.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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