SPRINT-MS was a phase II study designed to assess the effectiveness and safety of ibudilast (MN-166) in people with progressive MS. 255 people with secondary and primary progressive MS took either ibudilast or placebo as tablets twice daily for nearly two years. MRI was used to measure brain volume at the beginning and end of the study. Compared to placebo, ibudilast slowed down the loss of brain volume (brain atrophy) by 48%.
Loss of brain volume is linked to cognitive and physical disability in MS and is used as a marker for MS progression; slowing down the rate at which brain volume is lost indicates that ibudilast is slowing down progression in MS.
Another advanced MRI imaging technique also provided some evidence that ibudilast reduced further damage to myelin and nerve cells. Further analysis of the trial results is underway.
Ibudilast was generally well-tolerated. The most common side effects associated with ibudilast included gastrointestinal problems such as nausea, diarrhoea and abdominal pain, as well as depression, rash and fatigue.
What next for ibudilast?
While these promising results indicate that ibudilast may slow down progression in MS, the drug will need to be tested in larger phase III clinical studies using more direct measures of disability such as mobility, hand/arm function and cognition.
More about ibudilast
Ibudilast is used in Japan and Korea to treat asthma and some complications of stroke. It acts on a number of cell processes associated with nerve damage and myelin repair. Previous studies have suggested it may have a neuroprotective effect.