Masitinib inhibits the function of proteins called tyrosine kinase that target mast cells and macrophages which are involved in inflammatory and immune responses. Blocking tyrosine kinases results in inhibition of the inflammatory process.
Phase II Trial
In a small phase II, multicenter, randomized study, 35 people with primary progressive MS and relapse-free secondary progressive MS took either masitinib (3 to 6 mg/kg/day) or placebo for at least 12 months. The primary outcome measure was a change in the Multiple Sclerosis Functional Composite (MSFC) which measures changes in leg function/walking, arm/hand function, and cognitive function and showed improvement for the masitinib-treated group compared with those in the placebo group. While the results were not statistically significant, they showed enough therapeutic benefit to support a larger clinical trial.
Phase III Trial AB07002
A phase III, multi-center, randomized, double-blind clinical trial was designed to examine the safety and efficacy of masitinib (4.5 mg/kg/day or 4.5 mg/kg/day progressing to 6 mg/kg/day) compared with placebo in 656 adults with PPMS and relapse-free SPMS over 96 weeks. The primary outcome measure was the effectiveness of masitinib through changes in Expanded Disability Status Scale (EDSS), which quantifies the level of disability. Other outcome measures include the MSFC and Multiple Sclerosis Quality of Life-54 (MSQOL-54) which assesses quality of life. In January 2018, the results of an interim analysis revealed no safety concerns and predicted a high success rate with the current sample size. Unpublished results showed that treatment with masitinib (4.5 mg/kg/day) was associated with 39% relative probability of either reducing EDSS progression or increasing EDSS improvement as compared to the placebo group. Furthermore, masitinib treatment significantly reduced the risk of first disability progression by 42%. This study offers encouraging results for people with progressive MS who have very limited treatment options. A confirmatory study is currently being developed by the drug developer.
Vermersch P, et al. Masitinib treatment in patients with progressive multiple sclerosis: a randomized pilot study. BMC Neurol . 2012;12:36.