Blueprint Medicines Corporation announced updates on the AYVAKIT/AYVAKYT (avapritinib) development program in systemic mastocytosis (SM): New analyses, which will be presented this week at the European Hematology Association (EHA) 2022 Congress, add to the growing body of clinical evidence supporting AYVAKIT as the standard of care for patients with advanced SM. Findings showed AYVAKIT improved overall survival (OS), as well as other clinical outcomes, in patients with advanced SM, when indirectly compared to real-world data for prior best available therapies. Based on these analyses, patients treated with AYVAKIT had a 41% reduction in the risk of death compared to patients treated with midostaurin and a 68% reduction in the risk of death compared to patients treated with cladribine.

In total, Blueprint Medicines is supporting the presentation of seven abstracts at the EHA 2022 Congress, highlighting the company's leadership in SM. In addition, Blueprint Medicines plans to update the primary endpoint of the registrational PIONEER trial of AYVAKIT in patients with non-advanced SM, based on a written recommendation from the U.S. Food and Drug Administration (FDA) on statistical considerations ahead of the planned database lock. The mean absolute change in total symptom score (TSS), previously a key secondary endpoint, will be the primary endpoint and the proportion of patients with a 30% or greater decrease in TSS, previously the primary endpoint, will be a key secondary endpoint.

Both analyses were previously defined as key endpoints that the PIONEER trial was powered to assess. In addition, both endpoints are based on the Indolent SM Symptom Assessment Form, a patient-reported outcomes tool that has been developed and validated in collaboration with the SM community and global regulatory authorities. Blueprint Medicines continues to plan to report top-line data from the PIONEER trial in late summer 2022 and submit a supplemental new drug application to the FDA for AYVAKIT for non-advanced SM by the end of 2022.