Blueprint Medicines Announces Publication of BLU-285 Translational Data

CAMBRIDGE, Mass., Nov. 1, 2017 /PRNewswire/ -- Blueprint Medicines Corporation (NASDAQ: BPMC), a leader in discovering and developing targeted kinase medicines for patients with genomically defined diseases, today announced the publication of translational data for its investigational medicine BLU-285 in Science Translational Medicine. Reported preclinical data and clinical case studies showed that BLU-285 is a potent and highly selective inhibitor of KIT and PDGFRα kinases, which are implicated in multiple diseases including gastrointestinal stromal tumors (GIST) and systemic mastocytosis (SM). Blueprint Medicines is currently evaluating BLU-285 in two ongoing Phase 1 clinical trials in patients with advanced GIST and patients with advanced SM, and plans to present updated results from both clinical trials in the fourth quarter of 2017.

"The publication of our work in Science Translational Medicine highlights the power of our proprietary drug discovery platform to successfully target specific drivers of disease with potent and highly selective kinase medicines," said Erica Evans, Ph.D., Senior Director of Biology at Blueprint Medicines and the lead author of the paper. "Importantly, the preclinical activity of BLU-285 has been substantiated in our ongoing Phase 1 clinical trials. BLU-285 has induced meaningful responses and prolonged progression free survival in patients with KIT-driven and PDGFRα-driven GIST, as well as objective and clinically significant decreases in mast cell burden and improvements in symptoms in patients with advanced SM. We look forward to presenting additional data from our ongoing trials at upcoming medical meetings and continuing to rapidly advance the development of BLU-285 for patients with these severe diseases."

The paper highlighted the in-depth mechanistic evaluation conducted by Blueprint Medicines' scientists to characterize the activity of BLU-285 across a continuum of clinically relevant oncogenic KIT and PDGFRα mutations.

Key insights included:

• Currently available therapies for advanced GIST and advanced SM have limited activity against KIT and PDGFRα activation loop mutations, including KIT D816V, PDGFRα D842V, and additional resistance mutations located on exons 17 and 18. These mutations induce the KIT and PDGFRα proteins to adopt an active conformation, resulting in structural changes in the kinases that decrease the binding affinity of current therapeutic agents. BLU-285 was specifically designed to inhibit KIT and PDGFRα activation loop mutations.
• In vitro studies demonstrated potent activity of BLU-285 against activation loop mutations, as well as a broad spectrum of additional clinically relevant mutations, with a selectivity profile minimizing inhibition of other kinases. In vivo studies in multiple disease models showed BLU-285 induced potent anti-tumor effects.
• BLU-285 has demonstrated clinical proof-of concept in ongoing Phase 1 clinical trials in patients with advanced GIST and advanced SM.

The paper, titled "A precision therapy against cancers driven by KIT/PDGFRA mutations" was published online in Science Translational Medicine on November 1, 2017.

About BLU-285

BLU-285, an investigational medicine, is an orally available, potent and highly selective inhibitor of KIT and PDGFRα. Blueprint Medicines is initially developing BLU-285 for the treatment of patients with advanced GIST and advanced SM.

In June 2017, BLU-285 received breakthrough therapy designation from the U.S. Food and Drug Administration (FDA) for the treatment of patients with unresectable or metastatic GIST harboring the PDGFRα D842V mutation. Previously, the FDA granted orphan drug designation to BLU-285 for the treatment of GIST and SM. The FDA also granted fast track designation to BLU-285 for the treatment of patients with unresectable or metastatic GIST that progressed following treatment with imatinib and a second tyrosine kinase inhibitor and for the treatment of patients with unresectable or metastatic GIST who have the PDGFRα D842V mutation regardless of prior therapy.

BLU-285 was discovered by Blueprint Medicines' research team, which leveraged its proprietary compound library. The Company retains worldwide development and commercialization rights for BLU-285.

About GIST

GIST is the most common sarcoma, or tumor of bone or connective tissue, of the gastrointestinal (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 50-80, and diagnosis is typically triggered by GI bleeding, incidental findings during surgery or imaging and, in rare cases, tumor rupture or GI obstruction. Approximately 80 percent of GIST patients have KIT-driven GIST, and Blueprint Medicines estimates that KIT exon 17 mutations occur in approximately 90 percent of GIST patients with KIT-driven GIST following treatment with at least two tyrosine kinase inhibitors. Approximately five percent of all advanced GIST cases are driven by D842V mutant PDGFRα. Patients diagnosed with GIST at an early stage may undergo surgery. For patients with KIT-driven GIST, treatment with the currently approved frontline therapy typically leads to treatment resistance and disease progression. Treatment options for KIT-driven GIST patients whose disease progresses or develops resistance are currently limited, with approved therapies providing a progression free survival of up to six months and a response rate between five percent and seven percent. There are no effective treatment options for patients with PDGFRα D842V-driven GIST, and progression often occurs in as little as three months with available treatment options.

About SM

There are several forms of SM, including indolent SM and more advanced forms of SM, which include aggressive SM, SM with an associated hematologic neoplasm (SM-AHN) and mast cell leukemia (MCL). SM is characterized by the buildup of mast cells, which are immune cells that produce histamine and other mediators of the body's inflammatory and allergic responses. In patients with SM, mast cell mediator release leads to mild to life-threatening symptoms, including pain, nausea, rash, fever, fatigue and anaphylaxis. In patients with advanced SM, including aggressive SM, SM-AHN and MCL, mast cell infiltration in bone marrow, liver and other vital organs can eventually lead to organ dysfunction and lower life expectancy, with a median overall survival of approximately four years or less. Patients with indolent SM have a normal life expectancy, but symptoms can have a significant impact on their quality of life. The KIT D816V mutation is the primary driver of disease in approximately 90 to 95 percent of SM patients, and there is a clear need for more effective therapies for patients with advanced SM and for patients with indolent SM who have a heavy symptom burden. 

About Blueprint Medicines

Blueprint Medicines is developing a new generation of targeted and potent kinase medicines to improve the lives of patients with genomically defined diseases. Its approach is rooted in a deep understanding of the genetic blueprint of cancer and other diseases driven by the abnormal activation of kinases. Blueprint Medicines is advancing four programs in clinical development for subsets of patients with gastrointestinal stromal tumors, hepatocellular carcinoma, systemic mastocytosis, non-small cell lung cancer, medullary thyroid cancer and other advanced solid tumors, as well as multiple programs in research and preclinical development. For more information, please visit www.blueprintmedicines.com.

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 the potential for BLU-285 to address unmet patient needs in GIST and SM; plans and timelines for the clinical development of BLU-285; the timing of updated clinical data for Blueprint Medicines' Phase 1 clinical trials for BLU-285; and Blueprint Medicines' strategy, business plans and focus. The words "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 delay of any current or planned clinical trials or the development of Blueprint Medicines' drug candidates, including BLU-285, BLU-554 and BLU-667; Blueprint Medicines' advancement of multiple early-stage efforts; Blueprint Medicines' ability to successfully demonstrate the efficacy and safety of its drug candidates; the preclinical and clinical results for Blueprint Medicines' drug candidates, which may not support further development of such drug candidates; and 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, including companion diagnostic tests for BLU-554 for FGFR4-driven HCC, BLU-285 for PDGFRα D842V-driven GIST and BLU-667 for RET-driven NSCLC; and the success of Blueprint Medicines' cancer immunotherapy collaboration with F. Hoffmann-La Roche Ltd and Hoffmann-La Roche Inc. These and other risks and uncertainties are described in greater detail in the section entitled "Risk Factors" in Blueprint Medicines' Quarterly Report on Form 10-Q for the quarter ended September 30, 2017, as filed with the Securities and Exchange Commission (SEC) on October 31, 2017, and other filings that Blueprint Medicines 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. Blueprint Medicines explicitly disclaims any obligation to update any forward-looking statements.

SOURCE Blueprint Medicines

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