Sec Form 4 Filing - Flynn James E @ AveXis, Inc. - 2015-09-03

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 Flynn James E 2. Issuer Name and Ticker or Trading Symbol AveXis, Inc. [ AVXS] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) X __ Other (specify below) Possible Member of 10% Group (Last) (First) (Middle) 780 THIRD AVENUE, 37TH FLOOR, 3. Date of Earliest Transaction (MM/DD/YY) 09/03/2015 (Street) NEW YORK, NY10017 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (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 09/03/2015 P 131,911 A $ 18.48 ( 1 ) 131,911 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Common Stock 09/03/2015 P 131,911 A $ 18.48 ( 1 ) 131,911 I Through Deerfield Special Situations Fund, L.P. ( 3 ) ( 4 ) Common Stock 02/17/2016 C 67,448 A 199,359 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Common Stock 02/17/2016 C 1,182,941 A 1,382,300 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Common Stock 02/17/2016 C 117,996 A 1,500,296 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Common Stock 02/17/2016 C 117,998 A 249,909 I Through Deerfield Special Situations Fund, L.P. ( 3 ) ( 4 ) Common Stock 02/17/2016 P 122,793 A $ 20 1,623,089 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Common Stock 02/17/2016 P 163,702 A $ 20 413,611 I Through Deerfield Special Situations Fund, L.P. ( 3 ) ( 4 ) Common Stock 02/17/2016 P 88,000 A $ 20 88,000 I Through Deerfield Partners, L.P. ( 3 ) ( 4 ) Common Stock 02/17/2016 P 112,000 A $ 20 112,000 I Through Deerfield International Master Fund, L.P. ( 3 ) ( 4 )

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 Class D Preferred Stock ( 1 ) 09/03/2015 P 117,996 ( 1 ) ( 1 ) Common Stock 117,996 $ 21.01 ( 1 ) 0 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Class D Preferred Stock ( 1 ) 09/03/2015 P 117,998 ( 1 ) ( 1 ) Common Stock 117,998 $ 21.01 ( 1 ) 0 I Through Deerfield Special Situations Fund, L.P. ( 3 ) ( 4 ) Class B-1 Preferred Stock ( 2 ) 02/17/2016 C 67,448 ( 2 ) ( 2 ) Common Stock 67,448 ( 2 ) 0 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Class C Preferred Stock ( 2 ) 02/17/2016 C 1,182,941 ( 2 ) ( 2 ) Common Stock 1,182,941 ( 2 ) 0 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Class D Preferred Stock ( 2 ) 02/17/2016 C 117,996 ( 2 ) ( 2 ) Common Stock 117,996 ( 2 ) 0 I Through Deerfield Private Design Fund III, L.P. ( 3 ) ( 4 ) Class D Preferred Stock ( 2 ) 02/17/2016 C 117,998 ( 2 ) ( 2 ) Common Stock 117,998 ( 2 ) 0 I Through Deerfield Special Situations Fund, L.P. ( 3 ) ( 4 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Flynn James E 780 THIRD AVENUE, 37TH FLOOR NEW YORK, NY10017 X X Possible Member of 10% Group Deerfield Mgmt L.P. 780 THIRD AVENUE 37TH FLOOR NEW YORK, NY10017 X Possible Member of 10% Group DEERFIELD MANAGEMENT CO 780 THIRD AVENUE, 37TH FLOOR NEW YORK, NY10017 X Possible Member of 10% Group Deerfield Special Situations Fund, L.P. 780 3RD AVENUE 37TH FLOOR NEW YORK, NY10017 X Possible Member of 10% Group DEERFIELD PARTNERS, LP 780 THIRD AVENUE 37TH FLOOR NEW YORK, NY10017 X Possible Member of 10% Group Deerfield International Master Fund, L.P. 780 THIRD AVENUE, 37TH FLOOR NEW YORK, NY10017 X Possible Member of 10% Group Deerfield Mgmt III, L.P. 780 THIRD AVENUE, 37TH FLOOR NEW YORK, NY10017 X Possible Member of 10% Group Deerfield Private Design Fund III, L.P. 780 THIRD AVENUE, 37TH FLOOR NEW YORK, NY10017 X Possible Member of 10% Group Signatures /s/ Jonathan Isler 02/19/2016 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The amounts reflect a 1.38-for-1 forward stock split of the Preferred Stock (as defined below) effected by the Issuer on February 1, 2016. ( 2 )Each share of Class B-1 Preferred Stock, Class C Preferred Stock and Class D Preferred Stock (collectively, the "Preferred Stock") automatically converted into 1 share of the Issuer's Common Stock upon the closing of the Issuer's initial public offering of Common Stock. ( 3 )This Form 4 is being filed by the undersigned as well as the entities listed on the Joint Filer Information Statement attached as an exhibit hereto (the "Reporting Persons"). Deerfield Mgmt III, L.P. is the general partner of Deerfield Private Design Fund III, L.P. ("Fund III"). Deerfield Mgmt, L.P. is the general partner of Deerfield Special Situations Fund, L.P., Deerfield Partners, L.P. and Deerfield International Master Fund, L.P. (together with Fund III, the "Funds"). Deerfield Management Company, L.P. is the investment manager of the Funds. James E. Flynn is the sole member of the general partner of each of Deerfield Mgmt, L.P., Deerfield Mgmt III, L.P. and Deerfield Management Company, L.P. ( 4 )In accordance with Instruction 4 (b)(iv) to Form 4, the entire amount of the Issuer's securities held by the Funds is reported herein. For purposes of Section 16 of the Securities Exchange Act of 1934, as amended, each Reporting Person disclaims beneficial ownership of any such securities, except to the extent of his/its indirect pecuniary interest therein, if any, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of such securities for purposes of Section 16 or otherwise.

Remarks: Jonathan S. Leff, a partner in Deerfield Management Company, L.P., serves as a director of the Issuer.Jonathan Isler, Attorney-in-Fact: Power of Attorney, which is hereby incorporated by reference to Exhibit 24 to a Form 3 with regard to Editas Medicine, Inc. filed with the Securities and Exchange Commission on February 2, 2016 by Deerfield Mgmt, L.P., Deerfield Mgmt III, L.P., Deerfield Management Company, L.P., Deerfield Special Situations Fund, L.P., Deerfield Partners, L.P., Deerfield Private Design Fund, L.P., Deerfield Private Design International, L.P., Deerfield PDI Financing, L.P., Deerfield PDI Financing II, L.P., Deerfield Private Design Fund II, L.P., Deerfield Private Design International II, L.P., Deerfield International Master Fund, L.P., Deerfield Healthcare Innovations Fund, L.P., Deerfield Mgmt HIF, L.P., Breaking Stick Holdings, LLC, Deerfield Private Design Fund III, L.P. and James E. Flynn.

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).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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