Avapritinib was approved by FDA for advanced systemic mastocytosis

The Food and Drug Administration(FDA) approved avapritinib for adult patients with advanced systemic mastocytosis, including patients with aggressive systemic mastocytosis (ASM), systemic mastocytosis with an associated hematological neoplasm (SM-AHN), and mast cell leukemia (MCL). The recommended avapritinib dose is 200 mg orally once daily for patients with AdvSM. Avapritinib is not recommended for the treatment of patients with AdvSM with platelet counts of less than 50 X 10⁹/L.

The ORR in all evaluable patients in both trials combined (EXPLORER & PATHFINDER) was 57% (95% CI: 42, 70) (n=53), with 28% complete remissions and 28% partial remissions. The median duration of response was 38.3 months (95% confidence interval: 19, not estimable) and the median time to response was 2.1 months.

What is Mastocytosis?

Mastocytosis is a rare condition caused by an excess number of mast cells gathering in the body’s tissues.

There are 2 main types of mastocytosis:

• cutaneous mastocytosis, which mainly affects children – where mast cells gather in the skin, but are not found in large numbers elsewhere in the body
• systemic mastocytosis, which mainly affects adults – where mast cells gather in body tissues, such as the skin, internal organs and bones.