Ibudilast in relapsing-remitting multiple sclerosis: a neuroprotectant?

Area of Science:

• Neuroscience
• Immunology
• Pharmacology

Background:

• Ibudilast, a phosphodiesterase inhibitor, is investigated for its anti-inflammatory and neuroprotective properties in multiple sclerosis (MS).
• This study assesses the safety and efficacy of two ibudilast dosages in patients with relapsing forms of MS.

Purpose of the Study:

• To evaluate the safety and tolerability of ibudilast in relapsing MS.
• To determine the effects of ibudilast on MRI-defined disease activity and clinical outcomes over 12 months.

Main Methods:

• A multicenter, double-blind, placebo-controlled, phase 2 trial involving 297 patients with relapsing MS.
• Patients received daily doses of 30 mg or 60 mg ibudilast or placebo for 12 months.
• Primary endpoint: cumulative number of newly active lesions; secondary endpoints included relapse rate, EDSS, lesion volumes, and brain volume change.

Main Results:

• No significant difference in newly active lesions or relapse rates between ibudilast and placebo groups.
• A significant reduction in percent brain volume change (PBVC) was observed with 60 mg ibudilast compared to placebo (p=0.04).
• Post hoc analyses indicated fewer active lesions evolving into persistent black holes with both ibudilast doses, and fewer patients experienced confirmed disability progression over 2 years.

Conclusions:

• Ibudilast did not demonstrate efficacy in reducing new lesions or relapses in relapsing MS.
• Preliminary MRI and clinical data suggest potential neuroprotective effects and a possible benefit in slowing disability progression.
• Ibudilast was generally safe and well-tolerated in this patient population.