Blueprint Medicines Announces Enrollment of First Patient in Phase 1 Clinical Trial for BLU-667

CAMBRIDGE, Mass., March 20, 2017 /PRNewswire/ -- Blueprint Medicines Corporation (NASDAQ: BPMC), a leader in discovering and developing targeted kinase medicines for patients with genomically defined diseases, today announced that it has dosed the first patient in a Phase 1 clinical trial of BLU-667, an investigational RET inhibitor for patients with non-small cell lung cancer (NSCLC), medullary thyroid cancer (MTC) and other advanced solid tumors that harbor a RET alteration.

"By rapidly initiating a clinical trial for our potent and selective RET inhibitor BLU-667, we have successfully achieved a key 2017 milestone," said Jeff Albers, Chief Executive Officer of Blueprint Medicines. "This continued progress underscores our commitment to build Blueprint Medicines into a sustainable company. BLU-667 has a unique product profile differentiated from our other clinical-stage programs by its potential to address predicted resistance mutations that may arise. With BLU-667 enrollment underway, we are further increasing our diversified pipeline of potent, highly selective investigational medicines that target specific disease drivers in genomically-defined patient populations."

"RET fusions and mutations are recognized as important drivers in multiple cancers, but existing multi-kinase inhibitors with RET activity do not provide sufficient, durable benefit for patients with RET alterations," said Andy Boral, M.D., Ph.D., Chief Medical Officer of Blueprint Medicines. "BLU-667 is being developed to potently inhibit RET, and simultaneously prevent the development of on-target resistance, which we believe will provide more lasting clinical benefit and prevent or delay disease recurrence. We look forward to working with patients and physicians to explore BLU-667's potential."

BLU-667 is an orally available, potent and selective inhibitor designed to target RET mutations, fusions and predicted resistance mutants. RET activating fusions and mutations are a key disease driver in multiple cancers, including NSCLC and MTC, with RET fusions implicated in approximately 1-2% of patients with NSCLC, and RET mutations implicated in approximately 60% of patients with MTC. In addition, genomic analyses published by scientists at Blueprint Medicines have identified RET fusions at low frequencies in colon and breast cancer. Currently, there are no approved therapies that selectively target RET-driven cancers, though there are several approved multi-kinase inhibitors with RET activity being evaluated in clinical trials.  Thus far, clinical activity attributable to RET inhibition has been uncertain for these inhibitors, likely due to insufficient inhibition of RET and off-target toxicities. In preclinical studies using biochemical and cellular assays, and tumor models, BLU-667 was active against RET fusions and mutations, including predicted resistance mutations.

About the Phase 1 Clinical Trial for BLU-667 in RET

Blueprint Medicines' Phase 1 clinical trial of BLU-667 in RET is designed to evaluate the safety and tolerability of BLU-667 in multiple ascending doses in patients with NSCLC, MTC, and other advanced solid tumors with the goal of establishing a maximum tolerated dose (MTD) or a lower recommended dose if appropriate. Once the MTD is reached, or a recommended dose is established, Blueprint Medicines plans to open expansion cohorts for NSCLC patients with a RET rearrangement, patients with MTC, and patients with RET-altered solid tumors other than NSCLC and MTC. Secondary objectives for this Phase 1 clinical trial include assessing the pharmacokinetic profile of BLU-667, assessing RET gene status in plasma and tumor tissue, characterizing the pharmacodynamic effects of BLU-667 and assessing response rate by Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1, which are criteria commonly used to measure clinical responses in solid tumors. The Phase 1 clinical trial is designed to enroll approximately 115 patients, including approximately 35 patients during dose escalation and approximately 80 additional patients in expansion cohorts, at multiple sites in the United States and the European Union. Please refer to www.clinicaltrials.gov (NCT03037385) for additional details related to this Phase 1 clinical trial. For more information, contact the study director for this Phase 1 clinical trial at [email protected].

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.

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 plans and timelines for the clinical development of BLU-667; Blueprint Medicines' ability to implement its clinical development plans for BLU-667 for the treatment of NSCLC, MTC and other advance solid tumors; Blueprint Medicines' ability to enroll patients in its Phase 1 clinical trial for BLU-667; 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, uncertainties related to market conditions. These and other risks and uncertainties are described in greater detail in the section entitled "Risk Factors" in Blueprint Medicines' Annual Report on Form 10-K for the year ended December 31, 2016, as filed with the Securities and Exchange Commission (SEC) on March 9, 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 Corporation