Blueprint Medicines Updates on Phase 1 Thyroid Cancer Trial Data

90 percent of evaluable MTC and PTC patients had tumor reductions
62 percent response rate in MTC patients treated with 300 to 400 mg once daily for at least 24 weeks
Patients with longest treatment durations remain on therapy for more than 15 months   

Blueprint Medicines Corporation (NASDAQ: BPMC), a leader in discovering and developing targeted kinase medicines for patients with genomically defined diseases, today announced the presentation of updated data from the ongoing Phase 1 ARROW clinical trial of BLU-667, an investigational precision therapy targeting RET alterations, including resistance mutations. The new results showed that BLU-667 was highly active and well-tolerated in patients with advanced RET-altered medullary thyroid cancer (MTC) and papillary thyroid cancer (PTC), with increased activity observed with higher dose levels and longer treatment durations.

The reported data showed 90 percent of evaluable patients with MTC and PTC had radiographic tumor reductions, regardless of RET alteration type or prior multi-kinase inhibitor (MKI) therapy. In addition, the response rate was 62 percent in patients with MTC treated once daily (QD) with BLU-667 at doses of 300 to 400 mg for at least 24 weeks. In the MTC and PTC populations, all responders across dose levels and all patients treated at 400 mg QD remain on study. Safety results were consistent with prior data, and the majority of adverse events (AEs) were Grade 1. These results were as of a data cutoff date of September 14, 2018 and were reported today in an oral presentation at The 88th Annual Meeting of the American Thyroid Association (ATA).

“Existing treatment of medullary and papillary thyroid cancer with multi-kinase inhibitors is limited by frequent dose modifications or interruptions due to off-target toxicities, reducing the opportunity for a meaningful or sustained response,” said Andy Boral, M.D., Ph.D., Chief Medical Officer of Blueprint Medicines. “These new data showed selectively targeting RET alterations with BLU-667 was well-tolerated and enabled durable responses. Importantly, response rates were high for patients with prolonged time on therapy at higher dose levels, demonstrating that potent and sustained target inhibition leads to improved patient outcomes. We believe these results begin to reveal the potential of BLU-667 to transform the care of patients with RET-altered thyroid cancer, and we look forward to seeing the data continue to mature as additional patients are treated at the recommended phase 2 dose for longer durations.”

Based on the encouraging data reported to date, Blueprint Medicines has expanded enrollment targets for the ARROW trial to further evaluate the safety and efficacy of BLU-667 in a broader patient population and, ultimately, to support potential registration.

https://www.biospace.com/article/releases/blueprint-medicines-announces-updated-data-from-phase-1-arrow-clinical-trial-showing-broad-durable-activity-of-blu-667-in-advanced-ret-altered-medullary-and-papillary-thyroid-cancers/