Blueprint Medicines announces first preclinical data for BLU6864

Blueprint Medicines has announced the first preclinical data for its drug candidate BLU6864, a RET-specific kinase inhibitor.

In preclinical studies, BLU6864 induced tumour regression in disease models driven by the primary RET fusion and all predicted secondary resistance mutations. RET is a key disease driver in multiple cancers.

“One of the greatest challenges in treating cancer is the cancer cell’s ability to mutate and become resistant to treatment,” said Alexander Drilon, M.D., a medical oncologist at Memorial Sloan Kettering Cancer Centre. “RET fusions fuel the development and growth of multiple cancers, including lung and thyroid cancers. By targeting both the main cancer driver and predicted resistance mutations that arise from targeted therapy, we hope to provide patients with transformative medicines that mount a more effective attack on this subset of cancers and prevent recurrences of the disease.”

BLU6864 induced tumour regression in cancer model driven by RET fusions

In the preclinical data, BLU6864:

• Inhibited tumour growth and induced tumour regression at well-tolerated doses in a model of cancer driven by RET fusions,
• Inhibited tumour growth and induced tumour regression in a model harbouring a resistance mutation that renders cancer cells insensitive to treatment with an approved multi-kinase inhibitor with activity against RET, and
• Spared VEGFR2, a kinase often inhibited together with RET and whose inhibition is associated with dose-limiting toxicities.

BLU6864 is one of the first kinase inhibitors designed specifically to inhibit RET.

In addition to BLU6864, Blueprint Medicines has two drug candidates on track to begin Phase 1 clinical trials in mid-2015, including BLU-554 in hepatocellular carcinoma and BLU-285 in metastatic and treatment-resistant gastrointestinal stromal tumours as well as systemic mastocytosis.