Blueprint Medicines Announces European Commission Approval of AYVAKYT® (avapritinib) for the Treatment of Adults with Unresectable or Metastatic PDGFRA D842V Mutant Gastrointestinal Stromal Tumors

CAMBRIDGE, Mass., Sept. 25, 2020 /PRNewswire/ -- Blueprint Medicines Corporation (NASDAQ: BPMC), a precision therapy company focused on genomically defined cancers, rare diseases and cancer immunotherapy, today announced that the European Commission (EC) has granted conditional marketing authorization to AYVAKYT® (avapritinib) as a monotherapy for the treatment of adult patients with unresectable or metastatic gastrointestinal stromal tumors (GIST) harboring the platelet-derived growth factor receptor alpha (PDGFRA) D842V mutation. For the first time in Europe, there is an approved therapy for patients with PDGFRA D842V mutant GIST specifically designed to target the underlying molecular driver of their disease.

The EC approval is based on efficacy results from the Phase 1 NAVIGATOR trial as well as combined safety results from the NAVIGATOR and Phase 3 VOYAGER trials. AYVAKYT demonstrated deep and durable clinical activity and was generally well-tolerated in patients with PDGFRA D842V mutant GIST with or without prior therapy. In 38 NAVIGATOR trial patients with PDGFRA D842V mutant GIST at a starting dose of 300 mg or 400 mg once daily, AYVAKYT had an overall response rate (ORR) of 95 percent (95% CI: 82.3%, 99.4%), with 13 percent of patients achieving a complete response, and the median duration of response (DOR) was 22.1 months (95% CI: 14.1 months, not estimable). The median progression-free survival (PFS) was 24 months, and the median overall survival (OS) was not reached. These efficacy data were reported earlier this month during the European Society for Medical Oncology (ESMO) Virtual Congress 2020. The most frequently reported adverse reactions (≥20 percent) were nausea, fatigue, anemia, periorbital edema, face edema, hyperbilirubinemia, diarrhea, vomiting, peripheral edema, increased lacrimation, decreased appetite and memory impairment.

GIST is a genomically driven sarcoma of the gastrointestinal (GI) tract, with PDGFRA D842V mutations implicated in a rare subset of patients. A retrospective study of patients with PDGFRA D842V mutant GIST showed that treatment with imatinib, the standard first-line GIST therapy, led to an ORR of 0 percent.² ESMO guidelines recommend including mutational testing in the GIST diagnostic work-up as standard practice.

"There have historically been no treatments offering hope for patients with PDGFRA D842V mutant GIST. AYVAKYT represents the first major therapeutic breakthrough for patients with GIST harboring this mutation, defining a new standard of care," said Sebastian Bauer, M.D., medical oncologist at the West German Cancer Center in Essen, and an investigator on the NAVIGATOR trial. "The NAVIGATOR trial confirmed that almost all patients with PDGFRA D842V mutant GIST achieved tumor shrinkage and clinical responses were durable. These patients have lived longer than what is expected based on historical outcomes, and side effects have been well-tolerated in most patients. With this approval, it is more important than ever to conduct mutational testing prior to first-line treatment, so that patients with PDGFRA D842V mutant GIST may begin therapy with AYVAKYT, the only effective treatment for their tumor type."

"This year, Blueprint Medicines has received three marketing approvals globally, highlighting our commitment to rapidly advance a portfolio of transformative treatments and effectively deliver them to patients worldwide," said Jeff Albers, Chief Executive Officer at Blueprint Medicines. "AYVAKYT is the first highly active treatment option for PDGFRA D842V mutant GIST, offering much-needed hope for this rare patient population who have long been underserved by existing therapies. As we progress toward our AYVAKYT launches in Europe, we are focused on raising awareness about the therapy's differentiated clinical profile and the importance of mutational testing, and working closely with health authorities to enable patient access to AYVAKYT as rapidly as possible."

In Europe, Blueprint Medicines plans to initiate its first commercial launch in Germany following the EC approval, and the timing of AYVAKYT availability will vary for other countries based on local reimbursement and access pathways. AYVAKYT will be available in 100 mg, 200 mg and 300 mg dose strengths, and the recommended starting dose is 300 mg once daily. As part of the conditional marketing authorization, Blueprint Medicines plans to conduct an observational, long-term study in patients with PDGFRA D842V mutant GIST treated with AYVAKYT.

"The introduction of a new targeted therapy, AYVAKYT, is an important milestone for patients with PDGFRA D842V mutant GIST, who have historically had no effective treatment options," said Markus Wartenberg, chair of Sarcoma Patients EuroNet Association (SPAEN). "We appreciate working with companies like Blueprint Medicines to advance treatment for those living with GIST, and empower the patient community through education and support."

About AYVAKYT (avapritinib)

AYVAKYT (avapritinib) is a kinase inhibitor approved in the EU for the treatment of adults with unresectable or metastatic GIST harboring the PDGFRA D842V mutation. AYVAKYT is the first precision therapy approved in Europe to treat a genomically defined population of patients with GIST. The EC previously granted orphan medicinal product designation for AYVAKYT for the treatment of GIST. This medicine was approved by the U.S. Food and Drug Administration (FDA) for the treatment of adults with unresectable or metastatic GIST harboring a PDGFRA exon 18 mutation, including PDGFRA D842V mutations, under the brand name AYVAKIT™.

This therapy is not approved for the treatment of any other indication in the U.S. or Europe, or for any indication in any other jurisdiction by any other health authority. It is being developed globally for the treatment of advanced and indolent systemic mastocytosis (SM). The FDA granted breakthrough therapy designation to AYVAKIT for the treatment of advanced SM, including the subtypes of aggressive SM, SM with an associated hematologic neoplasm and mast cell leukemia.

Blueprint Medicines has an exclusive collaboration and license agreement with CStone Pharmaceuticals for the development and commercialization of avapritinib in Mainland China, Hong Kong, Macau and Taiwan. Blueprint Medicines retains development and commercial rights for avapritinib in the rest of the world.

About GIST

GIST is a sarcoma, or tumor of bone or connective tissue, of the GI tract. Tumors arise from cells in the wall of the GI tract and occur most often in the stomach or small intestine. Most patients are diagnosed between the ages of 50 to 80, and diagnosis is typically triggered by GI bleeding, incidental findings during surgery or imaging and, in rare cases, tumor rupture or GI obstruction.

About 5 to 6 percent of primary GIST cases are caused by a PDGFRA D842V mutation, the most common PDGFRA exon 18 mutation. Published data have shown poor outcomes in patients with PDGFRA D842V mutant GIST treated with imatinib and other approved therapies, including a median OS of 15 months, a median PFS of 3 months and an ORR of 0 percent.²

About Blueprint Medicines

Blueprint Medicines is a precision therapy company striving to improve human health. With a focus on genomically defined cancers, rare diseases and cancer immunotherapy, we are developing transformational medicines rooted in our leading expertise in protein kinases, which are proven drivers of disease. Our uniquely targeted, scalable approach empowers the rapid design and development of new treatments and increases the likelihood of clinical success. We have two approved precision therapies and are currently advancing multiple investigational medicines in clinical development, along with a number of research programs. For more information, visit www.BlueprintMedicines.com and follow us on Twitter (@BlueprintMeds) and LinkedIn.

Cautionary Note Regarding Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended, including, without limitation, statements regarding Blueprint Medicines' views with respect to the approval of AYVAKYT and the implications of such approval for patients, caregivers and healthcare professionals; expectations regarding the potential benefits of AYVAKYT in treating patients; expectations concerning when AYVAKYT will be commercially available in Europe; and Blueprint Medicines' strategy, goals and anticipated milestones, business plans and focus. The words "aim," "may," "will," "could," "would," "should," "expect," "plan," "anticipate," "intend," "believe," "estimate," "predict," "project," "potential," "continue," "target" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. Any forward-looking statements in this press release are based on management's current expectations and beliefs and are subject to a number of risks, uncertainties and important factors that may cause actual events or results to differ materially from those expressed or implied by any forward-looking statements contained in this press release, including, without limitation, risks and uncertainties related to the impact of the COVID-19 pandemic to Blueprint Medicines' business, operations, strategy, goals and anticipated milestones, including Blueprint Medicines' ongoing and planned research and discovery activities, ability to conduct ongoing and planned clinical trials, clinical supply of current or future drug candidates, commercial supply of current or future approved products, and launching, marketing and selling current or future approved products; Blueprint Medicines' ability and plans in establishing a commercial infrastructure, and successfully launching, marketing and selling current or future approved products, including AYVAKIT and GAVRETO™ (pralsetinib); Blueprint Medicines' ability to successfully expand the approved indications for AYVAKIT and GAVRETO or obtain marketing approval for AYVAKIT and GAVRETO in additional geographies in the future; the delay of any current or planned clinical trials or the development of Blueprint Medicines' current or future drug candidates; Blueprint Medicines' advancement of multiple early-stage efforts; Blueprint Medicines' ability to successfully demonstrate the safety and efficacy of its drug candidates and gain approval of its drug candidates on a timely basis, if at all; the preclinical and clinical results for Blueprint Medicines' drug candidates, which may not support further development of such drug candidates; actions of regulatory agencies, which may affect the initiation, timing and progress of clinical trials; Blueprint Medicines' ability to develop and commercialize companion diagnostic tests for its current and future drug candidates; and the success of Blueprint Medicines' current and future collaborations, partnerships or licensing arrangements. These and other risks and uncertainties are described in greater detail in the section entitled "Risk Factors" in Blueprint Medicines' filings with the Securities and Exchange Commission (SEC), including Blueprint Medicines' most recent Annual Report on Form 10-K, as supplemented by its most recent Quarterly Report on Form 10-Q and any other filings that Blueprint Medicines has made or may make with the SEC in the future. Any forward-looking statements contained in this press release represent Blueprint Medicines' views only as of the date hereof and should not be relied upon as representing its views as of any subsequent date. Except as required by law, Blueprint Medicines explicitly disclaims any obligation to update any forward-looking statements.

References

¹ AYVAKYT® (avapritinib) Summary of Product Characteristics (EU). Blueprint Medicines (Netherlands) B.V., Amsterdam, Netherlands; September 2020.

² Cassier PA, Fumagalli E, Rutkowski P, et al. Outcome of patients with platelet-derived growth factor receptor alpha-mutated gastrointestinal stromal tumors in the tyrosine kinase inhibitor era. Clin Cancer Res. 2012;18(16):4458-4464.

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SOURCE Blueprint Medicines Corporation

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