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Table of Contents ( Mark One ) ✓ ■ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , DC 20549 1934 ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31 , 2020 OR TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF Form 10 - K For the transition period from Commission File Number : 001-37359 Delaware ( State or other jurisdiction of incorporation or organization ) BLUEPRINT MEDICINES CORPORATION ( Exact name of registrant as specified in its charter ) 45 Sidney Street Cambridge , MA ( Address of principal executive offices ) to Title of Class Common Stock , par value $ 0.001 per share 26-3632015 ( IRS Employer Identification No. ) 02139 ( Zip Code ) Registrant's telephone number , including area code : ( 617 ) 374-7580 Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbols BPMC Securities registered pursuant to Section 12 ( g ) of the Act : None Name of Exchange on Which Registered Nasdaq Global Select Market Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes No No No Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( § 232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes No Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company , or an emerging growth company . See definitions of " large accelerated filer , " " accelerated filer , " " smaller reporting company " and “ emerging growth company " in Rule 12b - 2 of the Exchange Act . Large accelerated filer Non - accelerated filer Accelerated filer Smaller reporting company Emerging growth company If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . □ Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . Yes No Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Act ) . Yes No As of June 30 , 2020 , the aggregate market value of the voting and non - voting common equity held by non - affiliates of the registrant , based on the last reported sales price for the registrant's common stock , par value $ 0.001 per share , on the Nasdaq Global Select Market on such date , was approximately $ 4,234,191,078 . Number of shares of the registrant's common stock , par value $ 0.001 per share , outstanding on February 15 , 2021 : 57,957,641 DOCUMENTS INCORPORATED BY REFERENCE Portions of the registrant's definitive proxy statement for its 2021 Annual Meeting of Stockholders , which the registrant intends to file with the Securities and Exchange Commission pursuant to Regulation 14A within 120 days after the end of the registrant's fiscal year ended December 31 , 2020 , are incorporated by reference into Part III of this Annual Report on Form 10 - K .