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                     February 11, 2021

       Michael Landsittel
       Chief Financial Officer
       Blueprint Medicines Corp
       45 Sidney Street
       Cambridge, Massachusetts 02139

                                                        Re: Form 10-K for the
Fiscal Year Ended December 31, 2019
                                                            Filed February 13,
2020
                                                            File No. 001-37359

       Dear Mr. Landsittel:

              We have completed our review of your filing. We remind you that
the company and its
       management are responsible for the accuracy and adequacy of their
disclosures, notwithstanding
       any review, comments, action or absence of action by the staff.




                     Sincerely,


                     Division of Corporation Finance

                     Office of Life Sciences