Statement of Changes in Beneficial Ownership (4)

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	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response... 0.5
	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 * Albers Jeffrey W.	2. Issuer Name and Ticker or Trading Symbol Blueprint Medicines Corp [ BPMC ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __ X __ Director                      _____ 10% Owner __ X __ Officer (give title below)      _____ Other (specify below) CEO and President
(Last)          (First)          (Middle) C/O BLUEPRINT MEDICINES CORPORATION, 45 SIDNEY STREET	3. Date of Earliest Transaction (MM/DD/YYYY) 3/15/2019
(Street) CAMBRIDGE, MA 02139 (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	3/15/2019		M (1)		20000	A	$1.87	48961	D
Common Stock	3/15/2019		S (1)		4451	D	$87.44   (2)	44510	D
Common Stock	3/15/2019		S (1)		9423	D	$86.41   (3)	35087	D
Common Stock	3/15/2019		S (1)		6126	D	$85.61   (4)	28961	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)	$1.87	3/15/2019		M   (1)			20000	(5)	7/30/2024	Common Stock	20000	$0	63080	D

Explanation of Responses:
(1)	Effected pursuant to a trading plan adopted on December 20, 2017 pursuant to Rule 10b5-1 under the Securities Exchange Act of 1934, as amended.
(2)	The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $86.95 to $87.94 per share. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2) through (4) to this Form 4.
(3)	The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $85.90 to $86.89 per share.
(4)	The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from $85.02 to $85.89 per share.
(5)	This option was granted on July 30, 2014. This option vests as follows: (i) 42,845 shares vested in four installments at a rate of 6,974 shares on September 21, 2016, and 11,957 shares on each of October 21, 2016 and November 21, 2016, and 11,957 on December 21, 2016; (ii) 90,010 shares vested in eight installments at a rate of 6,311 shares on May 21, 2017 and 11,957 shares on each of June 21, 2017, July 21, 2017, August 21, 2017, September 21, 2017, October 21, 2017, November 21, 2017 and December 21, 2017; and (iii) 30,225 shares vest in three installments at a rate of 6,311 shares on May 21, 2018, 11,957 shares on June 21, 2018 and 11,957 shares on July 21, 2018.

Reporting Owners
Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Albers Jeffrey W. C/O BLUEPRINT MEDICINES CORPORATION 45 SIDNEY STREET CAMBRIDGE, MA 02139	X		CEO and President

Signatures
/s/ Christopher Frankenfield, Attorney-in-Fact		3/19/2019
** Signature of Reporting Person		Date

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).
Note:	File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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