Blueprint Medicines presents preclinical data demonstrating significant anti-tumour activity of BLU-285 in treatment-resistant GIST

Blueprint Medicines has announced new preclinical data demonstrating that its drug candidate BLU-285 has significant anti-tumour activity in treatment-resistant models of gastrointestinal stromal tumours (GIST) and achieved and maintained complete tumour regression in all mice treated at the highest dose level.

These data were presented at the American Association for Cancer Research (AACR) Annual Meeting 2015.

BLU-285 is a highly targeted drug that potently and selectively inhibits PDGFRα D842V and KIT Exon 17 mutants, which are receptor tyrosine kinase mutants known to be key drivers in treatment-resistant and metastatic GIST. Preclinical data shows that BLU-285 achieved and maintained complete tumour remission in 100% of mice treated with an oral, once daily dose of 30 mg/kg or 100 mg/kg for 28 days. Complete tumour regression was maintained during a 28-day observation period following treatment at the 100 mg/kg dose.

BLU-285 could offer a highly targeted therapy for patients who have no effective treatment options

“Despite advances in treating GIST, there are still subsets of patients who do not respond to currently available treatments or relapse and become resistant to treatment,” said Suzanne George, MD, Clinical Director, Centre for Sarcoma and Bone Oncology and Senior Physician at the Dana Farber Cancer Institute and Assistant Professor of Medicine at Harvard Medical School. “By inhibiting PDGFRα D842V and KIT Exon 17 mutants, which are key drivers of treatment-resistant GIST, BLU-285 could offer a highly targeted therapy for patients who have no effective treatment options. In addition, the selectivity of BLU-285 for these mutants may allow for less off-target toxicity than currently available agents, opening the door to future combination therapy strategies.”

The Company also presented data identifying new cancer drug targets during a minisymposium at AACR on cancer genomics. Using proprietary computational tools to identify kinase fusions involved in cancer, Blueprint Medicines uncovered 16 known fusions in new cancer types and identified 21 novel fusions across six genes that likely play a key role in cancer. In addition to paving the way for the discovery and development of novel therapies, these findings could have immediate implications for the diagnosis and treatment of cancer patients.

Phase 1 clinical trials of BLU-285 planned for mid-2015

“These presentations demonstrate the power of Blueprint Medicines’ discovery engine to identify promising new drug targets and craft highly selective kinase inhibitors against previously unaddressed genomic drivers of cancer,” said Blueprint Medicines Chief Scientific Officer Christoph Lengauer, PhD, MBA. “Kinases play a key role in virtually every aspect of cancer, and there is tremendous untapped potential to deliver much-needed new therapies for patients with genomically defined diseases based on a deep understanding of cancer’s blueprint.”

Blueprint Medicines is on track to file an Investigational New Drug (IND) Application and begin a Phase 1 clinical trial of BLU-285 in mid-2015. The Company also plans to file an IND and begin a Phase 1 clinical trial in mid-2015 for BLU-285 in patients with systemic mastocytosis.