Ibudilast Phase 2


  • Also known as MS-166
  • Pharmaceutical Company: MedicNova
  • Route and Dose of Administration: Oral (100mg/day)
  • Type: Phosphodiesterase inhibitor; neuroprotective
  • Emerging Treatment for Primary Progressive MS (PPMS) and secondary progressive MS (SPMS)
  • Status: In Phase II clinical trial

How it Works

Ibudilast works by suppressing three cell signaling molecules that promote inflammation: IL-1β, TNF-α, and IL-6. Ibudilast may also upregulate anti-inflammatory cell signaling molecules resulting in neuroprotective effects and reduced neuroinflammation. Ibudilast has been approved in Japan and Korea to treat asthma and cerebrovascular disorder for over 20 years.

Research and Results

Phase II Trial- Relapsing-Remitting MS (RRMS)

A multicenter, double-blind, placebo-controlled phase II trial recruited 297 people with RRMS. Participants were randomized to receive ibudilast (30 or 60 mg /day) or placebo for 12 months. Treatment with ibudilast had no effect of the treatment on the number of active lesions or relapse rate. There may be a neuroprotective effect as fewer people witnessed confirmed disease progression and displayed reduced brain atrophy.

SPRINT MS: Phase II Trial

SPRINT-MS, a phase II randomized, double-blind, placebo-controlled, multicenter clinical trial tested the efficacy and safety of ibudilast in 255 people with PPMS and SPMS. Study participants received either ibudilast twice daily for a total dose of 100mg, or placebo over the course of two years. Those in the ibudilast group had a 48% reduction in brain atrophy as compared with placebo. Ibudilast also met its second primary outcome of safety and tolerability. A larger phase III trial is required to fully test the effectiveness of ibudilast in MS.

Adverse Effects Reported

The adverse effects reported from the SPRINT-MS trial included gastrointestinal issues, such as nausea, diarrhea, and abdominal pain. Other adverse events reported include depression and fatigue.


Barkhof f et al. Ibudilast in relapsing-remitting multiple sclerosis: a neuroprotectant? Neurology. 2010; 74(13):1033-40