Rationale for Correct Answer
The correct answer is: Inhibits activity of pro-inflammatory mast cells
Masitinib is a selective tyrosine kinase inhibitor that inhibits the inflammatory processes of mast cells, microglia, and macrophages.1 It binds primarily to the c-kit receptor, with additional binding to growth factor receptors platelet-derived growth factor (PDGRF) and fibroblast growth factor receptor 3 (FGFR3), as well as the non-receptor, intracellular tyrosine kinases Lck/Lyn and focal adhesion kinase (FAK).1 It acts independently of Bruton’s tyrosine kinase, the tyrosine kinase inhibited by fenebrutinib and tolebrutinib.1,2 No direct effects of masitinib on phosphodiesterase or T-cell activity have been reported.
References:
1. Gągało I et al. Curr Neuropharmacol. 2015;13:836-844.
2. Garg N et al. J Clin Med. 2022; 11:6139.