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EX - 99.1 2 tm2119616d1_ex99-1.htm EXHIBIT 99.1 Exhibit 99.1 FDA Approves Blueprint Medicines ' AYVAKIT ™ ( avapritinib ) for the Treatment of Adults with Advanced Systemic Mastocytosis - First precision therapy that specifically targets the primary driver of the disease -- --Durable clinical responses , including complete remissions , shown in patients with or without prior treatment -- -- Full approval supported by robust efficacy and safety data from two clinical trials -- -- Blueprint Medicines to host investor conference call and webcast today at 4:30 p.m. ET -- CAMBRIDGE , Mass . , June 16 , 2021 - Blueprint Medicines Corporation ( NASDAQ : BPMC ) today announced that the U.S. Food and Drug Administration ( FDA ) has approved AYVAKIT ™ ( avapritinib ) for the treatment of adult patients with advanced systemic mastocytosis ( Advanced SM ) , including aggressive SM ( ASM ) , SM with an associated hematological neoplasm ( SM - AHN ) and mast cell leukemia ( MCL ) . For the first time , advanced SM patients can now receive a targeted therapy designed to potently and selectively inhibit D816V mutant KIT , the central driver of the disease . " Today's approval of AYVAKIT for advanced systemic mastocytosis - the fourth FDA approval across our portfolio in 18 months - culminates nearly a decade of hard work , from our scientists in the laboratory and clinical team conducting trials , to our commercial organization who will now bring AYVAKIT to patients , " said Jeff Albers , Chief Executive Officer of Blueprint Medicines . " As shown in two clinical trials , AYVAKIT provides remarkable clinical efficacy to patients with advanced systemic mastocytosis , and this approval solidifies the therapy's strong value proposition in this population . With a deep commitment to driving continued research innovation in collaboration with the mast cell disease community , we are now building on this progress with the goal of bringing the benefits of precision therapy to a broader range of patients through our ongoing and planned clinical trials for non - advanced systemic mastocytosis . " SM is a rare hematologic disorder caused by the KIT D816V mutation in nearly all cases . Across advanced SM subtypes , the median overall survival is approximately 3.5 years in ASM , approximately two years in SM - AHN and less than six months in MCL.¹ " Advanced systemic mastocytosis is a debilitating disease characterized by extensive damage in multiple organ systems due to mast cell infiltration , and new treatment options are urgently needed to address these life - threatening complications , ” said Daniel DeAngelo , M.D. , Ph.D. , Chief of the Division of Leukemia at Dana - Farber Cancer Institute . " Avapritinib will clearly establish a new standard of care for patients with advanced systemic mastocytosis . The FDA approval was based on data showing robust and durable responses , including complete remissions , and a favorable safety profile . For advanced SM patients , the approval of avapritinib shifts the treatment paradigm toward precision therapy that targets the primary driver of mastocytosis . " The FDA granted full approval to AYVAKIT for adults with advanced SM based on data from the Phase 1 EXPLORER trial and Phase 2 PATHFINDER trial.² Treatment response was evaluated using modified IWG - MRT - ECNM criteria , with assessments based on at least 12 weeks of response duration , resolution of at least one finding of non - hematologic and hematologic organ damage , and 50 percent or greater reductions in biomarker response , mast cell burden and serum tryptase . The overall response rate ( ORR ) in the U.S. prescribing information is defined as complete remission with full or partial hematologic recovery ( CR / CRh ) , or partial remission ( PR ) . AYVAKIT showed durable clinical efficacy in advanced SM patients across disease subtypes and regardless of prior therapy . In 53 evaluable patients who had a median follow - up of 11.6 months , the ORR was 57 percent ( 95 % CI : 42 % , 70 % ) , and the proportion of patients with CR / CRh ( 28 percent ) , PR ( 28 percent ) and clinical improvement ( 15 percent ) is in line with previously reported results . The median duration of response was 38.3 months ( 95 % CI : 19 months , not estimable ) . Warnings and precautions include intracranial hemorrhage , cognitive effects and embryo - fetal toxicity . AYVAKIT is not recommended for the treatment of patients with advanced SM with low platelet counts ( less than 50,000 / µL ) , which is consistent with current patient eligibility criteria in the EXPLORER and PATHFINDER trials . The most common adverse reactions were edema , diarrhea , nausea and fatigue / asthenia .