Sanofi drug shows long-term benefit
Blueprint Medicines, a Sanofi company, announced new four-year data showing its drug AYVAKIT provides sustained benefits and long-term safety for patients with indolent systemic mastocytosis. The positive results, presented at the 2026 AAAAI Annual Meeting, reinforce the drug's efficacy in treating the rare blood disorder.
AYVAKIT is a precision therapy that targets the primary driver of systemic mastocytosis, the KIT D816V mutation, which is present in approximately 95% of cases. This mutation causes an uncontrolled proliferation of mast cells, leading to chronic and often unpredictable symptoms. The drug is a tyrosine kinase inhibitor designed to selectively block this mutated protein. Indolent systemic mastocytosis (ISM), the most common form of the disease, can cause a wide range of debilitating symptoms, including skin rashes, flushing, abdominal pain, diarrhea, brain fog, and bone pain. Prior to AYVAKIT's approval for ISM in May 2023, treatment primarily consisted of supportive care to manage these symptoms rather than addressing the underlying cause. The four-year PIONEER trial data shows AYVAKIT provided sustained improvements in overall symptoms across all domains, including skin, gastrointestinal, and neurocognitive. For instance, patients with frequent diarrhea at the study's start who took the drug for at least four years saw a median reduction in frequency of 65.6 percent. The long-term safety profile of AYVAKIT remained consistent with earlier findings from the 24-week placebo-controlled portion of the trial. The rate of discontinuation due to treatment-related adverse events was low at 3 percent. The most common side effects included eye edema, dizziness, peripheral edema, and flushing, with the majority of these events being mild. AYVAKIT is the first and only therapy approved by the FDA to treat the root cause of indolent systemic mastocytosis. It was previously approved in June 2021 for advanced systemic mastocytosis, a more aggressive form of the disease. The drug is also approved for a type of gastrointestinal stromal tumor (GIST).
