Statement of Changes in Beneficial Ownership (4)

FORM 4

[X] 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

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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

1. Name and Address of Reporting Person * Webster Stephen W	2. Issuer Name and Ticker or Trading Symbol Spark Therapeutics, Inc. [ ONCE ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director                    _____ 10% Owner __X__ Officer (give title below)    _____ Other (specify below) CHIEF FINANCIAL OFFICER
(Last)          (First)          (Middle) 3737 MARKET STREET, SUITE 1300	3. Date of Earliest Transaction (MM/DD/YYYY) 12/17/2019
(Street) PHILADELPHIA, PA 19104 (City)        (State)        (Zip)	4. If Amendment, Date Original Filed (MM/DD/YYYY)	6. Individual or Joint/Group Filing (Check Applicable Line) _X _ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security (Instr. 3)	2. Trans. Date	2A. Deemed Execution Date, if any	3. Trans. 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	12/17/2019		U		6102 (1)	D	$114.50	0	D

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Trans. Date	3A. Deemed Execution Date, if any	4. Trans. 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		7. Title and Amount of Securities Underlying Derivative Security (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)	$42.73	12/17/2019		D			35000	(2)	1/15/2029	Common Stock	35000	$0.00	0	D
Stock Option (Right to Buy)	$50.55	12/17/2019		D			28000	(2)	1/17/2028	Common Stock	28000	$0.00	0	D
Stock Option (Right to Buy)	$56.17	12/17/2019		D			25000	(2)	1/17/2027	Common Stock	25000	$0.00	0	D
Stock Option (Right to Buy)	$40.44	12/17/2019		D			55000	(2)	1/4/2026	Common Stock	55000	$0.00	0	D
Stock Option (Right to Buy)	$68.45	12/17/2019		D			60000	(2)	3/15/2025	Common Stock	60000	$0.00	0	D
Stock Option (Right to Buy)	$3.45	12/17/2019		D			106015	(2)	7/7/2024	Common Stock	106015	$0.00	0	D
Restricted Stock Units	$0.00	12/17/2019		D			19500	(3)	(3)	Common Stock	19500	$0.00	0	D

Explanation of Responses:
(1)	Disposed of pursuant to the Agreement and Plan of Merger, dated February 22, 2019, by and between Spark Therapeutics, Inc. ("Spark"), Roche Holdings, Inc. ("Roche") and 022019 Merger Subsidiary, Inc. ("Merger Sub") (the "Merger Agreement" and the transactions contemplated thereby, the "Merger"), whereby Roche caused Merger Sub to conduct a tender offer for all of the issued and outstanding shares of common stock, par value $0.001 per share, of Spark, at a price of $114.50 per share. On December 17, 2019, Merger Sub irrevocably accepted for payment all shares that were validly tendered and not withdrawn.
(2)	Pursuant to the terms of the Merger Agreement, immediately prior to the effective time of the Merger, each outstanding Spark stock option, whether vested or unvested, was converted into the right to an amount in cash (less applicable tax withholdings) equal to the product of (a) the excess of $114.50 over the per share exercise price of such stock option and (b) the total number of shares of common stock subject to such stock option.
(3)	Pursuant to the terms of the Merger Agreement, immediately prior to the effective time of the Merger, each outstanding Spark restricted stock unit, whether vested or unvested, was canceled and converted into the right to receive $114.50 in cash (less applicable tax withholdings).

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Webster Stephen W 3737 MARKET STREET SUITE 1300 PHILADELPHIA, PA 19104			CHIEF FINANCIAL OFFICER

Signatures
/s/ Joseph W. La Barge, Attorney-in-Fact		12/17/2019
**Signature of Reporting Person		Date