Blueprint's Ayvakit picks up long-awaited FDA approval in indolent systemic mastocytosis

In a development that's set to change the lives of many patients, Blueprint Medicines’ Ayvakit has finally won its long-awaited FDA approval to treat indolent systemic mastocytosis (SM).

The drug won its original approval in 2021 to treat the advanced form of the disease, which affects only 5% to 10% of those with SM. Now, Ayvakit can reach the majority of SM patients, who suffer from the disease’s indolent form.

The larger patient pool comprises approximately 30,000 U.S. patients, but so far only about half are diagnosed, Blueprint’s chief operating officer Christy Rossi told Fierce Pharma in an interview.

Indolent SM patients often end up “living their lives in a bubble,” Rossi said. Physicians can treat symptoms, which range across organ systems from skin lesions to brain fog, but until now there was no option to treat the underlying disease.

Enter Ayvakit. The drug targets a mutation called KIT D816V, which is the root cause of about 95% of indolent SM cases. In the PIONEER study supporting the approval, the drug showed it can reduce mast cell burden and ease patient symptoms.

In the trial, 141 patients received Ayvakit and 71 received placebo. For those treated with Ayvakit, investigators recorded improvements in symptoms based on changes in the Mastocytosis Quality of Life Questionnaire, plus an easing of mast cell burden.

Quality of life was an important factor to hit, because “all of these improvements are not worth it if you’re not improving their quality of life, their day to day living,” PIONEER investigator Pankit Vachhani, M.D., said in an interview with Fierce Pharma.

With the approval, Blueprint will continue its focus of educating doctors and patients about the disease. The company, armed with years of Ayvakit experience, is in a “really good position” to make the drug available to the new group of patients “very quickly," Rossi said. 

For Blueprint, Ayvakit is the culmination of more than a decade of research. This particular indication has been a company priority dating back to its 2008 founding. In many ways, SM is “part of the DNA of blueprint meds,” Rossi said.

Ayvakit brought in $39.1 million in sales during the first quarter, Blueprint reported. The company expects 2023 sales of the drug to land between $130 million to $140 million, a figure that doesn't factor in the new expansion.

Blueprint estimates the drug's peak sales will reach $1.5 billion, the company said during this year’s fourth-quarter earnings call.

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