AB Science has recruited the first patient in its Phase IIb/III study of masitinib in rheumatoid arthritis patients.
Masitinib is a selective inhibitor of the c-Kit and Lyn kinases, which play a key role in the survival and activation of mast cells and are involved in the immune response and inflammatory processes associated with rheumatoid arthritis.
The international, multicentre, randomised, double-blind and placebo-controlled study will enrol approximately 450 patients, and is designed to compare the efficacy and safety of masitinib at 3mg/kg/day and 6mg/kg/day to methotrexate in the treatment of patients with active rheumatoid arthritis.
In the study, the primary response evaluation will be the proportion of patients to achieve an improvement of at least 50% in their symptoms after 24 weeks of treatment.
Earlier Phase II studies tested masitinib as a single-agent and also in combination with methotrexate.
Both studies showed at least a 50% improvement in symptoms in 30% of patients resistant to methotrexate and also in approximately 30% of patients with resistance to anti-TNF alpha.