Masitinib (also known as Kinavet® and Masivet®)
Experimental Medications: Other Therapeutic Strategies
Masitinib is termed a protein kinase inhibitor. It selectively inhibits molecules (kinases) that play a major role in the activation of mast cells. Masitinib has a role in veterinary medicine (it is used to fight mast cell tumors in dogs) and is being studied for several human indications, including cancers and degenerative diseases. Mast cells are involved in the immune response, in the recruitment of lymphocytes to the brain, and also in inflammatory processes associated with MS. A small Phase II trial of masitinib in progressive MS61 showed a trend toward benefit; however, the results were not statistically significant.62
In 2012, results from a Phase II study of 30 patients taking masitinib were released. These indicated what is termed “proof of concept,” showing that this agent may have potential in treating both PPMS and relapse-free SPMS. The study investigated the hypothesis that masitinib’s action of targeting and inhibiting mast cells may delay the onset of symptoms associated with progressive forms of MS. The results showed that for the primary endpoint of Multiple Sclerosis Functional Composite (MSFC) score, which measures upper and lower limb function as well as cognition, 32 percent of patients treated with masitinib showed a response to treatment versus none of those receiving a placebo. Responses were seen in the third month and were sustained over the 18-month duration of the study.
A Phase IIb/III multicenter, randomized, double-blind, placebo-controlled trial63 is currently underway. The investigators planned to recruit 450 people with PPMS or SPMS without relapses. The primary endpoint will be an improvement in the MSFC scale at 96 weeks; results are expected in 2015.