Blueprint’s cancer drug might have a second life in rare disease

Blueprint Medicines has had a mixed record of clinical success with Ayvakit, an FDA-approved cancer drug. But new data suggest the treatment has a bright future as a treatment for a rare disorder that causes unpredictable allergic reactions.

In a pair of clinical trials, Avykit led to a roughly 75% response rate for patients with advanced systemic mastocytosis, a genetic disease that can cause life-threatening complications. In one study, the median length of response was more than three years. The company plans to file for an expanded FDA approval later this year, and analysts at Cowen expect Avykit to become the standard of care for advanced cases of the disease.

The news sent Blueprint’s share price up about 12% yesterday, in part because it bodes well for Avykit’s potential as a treatment for indolent systemic mastocytosis, a less severe and more common form of the disease. The drug appears safer than many investors inspected, according to SVB Leerink analyst Andrew Berens, which suggests that an ongoing study in indolent systemic mastocytosis, which uses a substantially lower dose, shouldn’t run into problems with toxicity.