Masitinib is an experimental drug treatment for secondary and primary progressive MS. It is taken as a tablet, twice daily.
Masitinib for secondary progressive MS: Phase III
Masitinib for primary progressive MS: Phase III
- Masitinib blocks a number of biochemical processes involved in inflammation and immune responses. It targets mast cells, a type of cell involved in allergic reactions.
- In a phase III study, masitinib slowed down disability progression in people with primary and relapse-free secondary progressive MS.
- The most common side effects reported in clinical trials have been weakness, rash, nausea, oedema (fluid retention) and diarrhoea.
Masitinib belongs to a class of drugs called tyrosine kinase inhibitors which block biochemical processes involved in inflammation and the immune responses. This results in a reduced immune response and less inflammation. Masitinib targets microglia, macrophages and mast cells, cells which are involved in allergy and inflammation.
Masitinib has been licensed in Europe for veterinary use. It is now being investigated in human diseases, including treatment of tumours, motor neurone disease, and Alzheimer's disease as well as secondary and primary progressive MS.
Masitinib is taken as a tablet, twice daily.
In a small phase II study, 35 people with primary and secondary progressive MS took either masitinib or placebo for 18 months. After 3 months of treatment those taking masitinib had an improvement in their MS Functional Composite (MSFC) score, a measure which assesses walking ability, hand and arm coordination and mental function. Those taking placebo had a worsening in their MSFC score. This difference between masitinib and placebo groups was maintained until the end of the study at 18 months. Other measures also showed some improvement for those taking masitinib, compared to placebo. While the results were not statistically significant, they gave grounds for a larger scale phase III study.
Masitinib in patients with primary progressive or relapse-free secondary multiple sclerosis (AB07002)
This phase III study recruited 611 participants with primary and non-active secondary progressive MS. Participants took one of two doses of masitinib or placebo for 96 weeks. The main measure of the study was change in EDSS. Other measures included Multiple Sclerosis Functional Composite (MSFC), which assesses walking ability, hand and arm coordination and mental function and MSQOL-54 which measures quality of life. The lower dose of masitinib (4.5 mg/kg/day) was statistically significantly better at slowing down disability progression measured by EDSS compared to placebo in both primary and secondary progressive MS. There was no difference in MSFC or MSQOL between low dose masitinib and placebo. The higher dose (6 mg/kg/day) was not effective at slowing down disability progression.
MAXIMS - masitinib compared to placebo in progressive MS
This study will recruit 800 participants with EDSS scores between 3.0 to 6.0 and non-active primary and secondary progressive MS (confirmed by absence of gadolinium-enhancing lesions on MRI). The study will test the effectiveness of masitinib 4.5 mg/kg/day compared to placebo taken for 96 weeks. The main measure of the study will be the time it takes to reach confirmed disability worsening.
Estimated completion date: December 2025
Further details of MAXIMS
Masitinib is relatively well tolerated with the most common side effects being asthenia (loss of strength and/or energy), rash, nausea, oedema (fluid retention) and diarrhoea.