A clinical trial testing Midamor (amiloride), Prozac (fluoxetine), and riluzole in people with secondary progressive multiple sclerosis (SPMS) failed to find a treatment benefit for any of the medications.
Despite these negative results, this study demonstrates the feasibility of testing multiple potential treatments in the same trial, which could allow for future trials that are more quick and efficient than traditional single-treatment studies.
The results were published in the journal The Lancet Neurology, in the study “Efficacy of three neuroprotective drugs in secondary progressive multiple sclerosis (MS-SMART): a phase 2b, multiarm, double-blind, randomised placebo-controlled trial.”
Randomized clinical trials typically compare the safety and/or effectiveness of a single medication to a placebo. This means that substantial resources — including personnel, equipment, time, and trial participants themselves — are necessary in order to test a single potential treatment.
Oncology research has pioneered the use of multiarm clinical trials, or trials with one placebo group and multiple different treatment groups. Although this strategy requires more resources than a single-arm trial, on a per-medication basis, it cuts down on overall resources required. This multiarm strategy has never before been applied in the context of neurodegenerative diseases.
The Phase 2 MS-SMART clinical trial (NCT01910259) tested the safety and efficacy of Midamor, Prozac, and riluzole in people with SPMS at 13 clinical neuroscience centers in the U.K. These three medications are all approved for other conditions, and they were chosen for this trial because previous data suggested they could promote the growth of axons (neuronal projections that are damaged in MS) and reduce the development of new brain lesions.
The study reports results from 393 participants who were randomly assigned to one of four groups — each of the three treatments and a placebo. The Prozac group had 96 patients, while the other three groups had 99 patients each. Trial participants had a mean age of 55, and about two-thirds were female. All enrolled were not using a disease-modifying therapy, and their Expanded Disability Status Scale (EDSS) scores ranged from 4.0 to 6.5, indicating notable to significant disability. They were treated for 96 weeks (about two years).
To ensure trial integrity, all three treatments and the placebo were delivered as identical pills.