Design, rationale, and baseline characteristics of the randomized double-blind phase II clinical trial of ibudilast in progressive multiple sclerosis

Contemp Clin Trials. 2016 Sep;50:166-77. doi: 10.1016/j.cct.2016.08.009. Epub 2016 Aug 10.


Background: Primary and secondary progressive multiple sclerosis (MS), collectively called progressive multiple sclerosis (PMS), is characterized by gradual progression of disability. The current anti-inflammatory treatments for MS have little or no efficacy in PMS in the absence of obvious active inflammation. Optimal biomarkers for phase II PMS trials is unknown. Ibudilast is an inhibitor of macrophage migration inhibitor factor and phosphodiesterases-4 and -10 and exhibits possible neuroprotective properties. The goals of SPRINT-MS study are to evaluate the safety and efficacy of ibudilast in PMS and to directly compare several imaging metrics for utility in PMS trials.

Methods: SPRINT-MS is a randomized, placebo-controlled, phase II trial of ibudilast in patients with PMS. Eligible subjects were randomized 1:1 to receive either ibudilast (100mg/day) or placebo for 96weeks. Imaging is conducted every 24weeks for whole brain atrophy, magnetization transfer ratio, diffusion tensor imaging, cortical brain atrophy, and retinal nerve fiber layer thickness. Clinical outcomes include neurologic disability and patient reported quality of life. Safety assessments include laboratory testing, electrocardiography, and suicidality screening.

Results: A total of 331 subjects were enrolled, of which 255 were randomized onto active study treatment. Randomized subjects were 53.7% female and mean age 55.7 (SD 7.3) years. The last subject is projected to complete the study in May 2017.

Conclusion: SPRINT-MS is designed to evaluate the safety and efficacy of ibudilast as a treatment for PMS while simultaneously validating five different imaging biomarkers as outcome metrics for use in future phase II proof-of-concept PMS trials.

Keywords: Clinical trial; Ibudilast; Magnetic resonance imaging; Progressive multiple sclerosis.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Brain / diagnostic imaging
  • Diffusion Tensor Imaging
  • Disease Progression
  • Double-Blind Method
  • Humans
  • Middle Aged
  • Multiple Sclerosis, Chronic Progressive / diagnostic imaging
  • Multiple Sclerosis, Chronic Progressive / drug therapy*
  • Phosphodiesterase Inhibitors / therapeutic use*
  • Pyridines / therapeutic use*
  • Quality of Life
  • Research Design


  • Phosphodiesterase Inhibitors
  • Pyridines
  • ibudilast