Masitinib

Masitinib inhibits KIT along with the LYN and FYN kinases that sit downstream of the high-affinity IgE receptor, giving it a proposed action on mast cell activation as well as on proliferation. Unlike avapritinib it is not selective for the D816V mutant, which is the pharmacologic reason its activity in D816V-positive disease has been questioned.

Masitinib is the only entry on this site with a trial registered in MCAS itself: NCT05449444, a Phase 2 study in severe mast cell activation syndrome. Its record has not been updated since February 2023, and ClinicalTrials.gov now carries it as status unknown — the registry’s own flag for a study whose sponsor has stopped updating past the expected completion date. The sponsor’s separate Phase 3 record in systemic mastocytosis, NCT04333108, is in the same state.

That is why this site takes trial statuses from the registry or the sponsor and from nowhere else. Secondary trackers tend to keep displaying the last confident-sounding status — “ongoing”, “recruiting” — with no indication that the underlying record has gone quiet. Two quiet records for the same drug is the situation those trackers describe least well, and it is the situation a reader most needs to know about.