 Masitinib AB1010 is a tyrosine kinase inhibitor TKI, selectively and effectively inhibiting c-kit. Its effect may include inhibition of cell proliferation, inhibition of cell cycle progression and induction of apoptosis resulting in the reduction of mast cell accumulation in body tissues. This drug is thereby specific to mastocytosis and active in slowing or reducing the number of mast cells particularly in aggressive forms of the disease. 