A 40-week phase 2B randomized, multicenter, double-blind, placebo-controlled study evaluating the safety and efficacy of memantine in amyotrophic lateral sclerosis

Abstract

Introduction: Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegenerative disease with no known cure, limited treatment options with minimal benefits, and significant unmet need for disease modifying therapies.

Aims: This study investigated memantine's impact on ALS progression, with an additional focus on the effects of memantine on cognitive and behavioral changes associated with the disease.

Methods: A randomized, double-blind, placebo-controlled clinical trial was conducted from December 2018 to September 2020. ALS patients were enrolled in-person and remotely across 13 sites in the United States. Participants were randomized to memantine (20 mg twice daily) or placebo in a 2:1 ratio and completed 36 weeks of treatment. The primary outcome of disease progression was assessed by the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R), and blood was collected for biomarker analysis.

Results: Of the 99 participants enrolled in the study, 89 were randomized to memantine or placebo (ages 24-83 years, male-to-female ratio ~3:2). Fifty-two participants completed the study treatment with no significant differences in disease progression, biomarker changes (including neurofilament light chain [NfL]), or neuropsychiatric testing noted between the groups. Initial NfL values correlated with the rate of ALSFRS-R decline.

Discussion: In this study, memantine did not impact ALS disease progression or neuropsychiatric symptoms. Trials with remote enrollment may help trial participation and success.

Keywords: amyotrophic lateral sclerosis (ALS); biomarkers; memantine; motor neuron disease (MND); neurofilament.

FIGURE 1

Study flow diagram. Ninety‐nine subjects were enrolled, and 89 subjects were randomized to memantine versus placebo in a 2:1 ratio. Primary endpoint analysis was performed on subjects that had greater than one Revised Amyotrophic Lateral Sclerosis Functional Rating Scale score.

FIGURE 2

(A) Correlation between NfL and ALSFRS‐R rates of change. Change in NfL values throughout the study showed a weak correlation (r = 0.28, p = .02) to ALSFRS‐R decline. (B) Impact of Initial NfL Level on ALSFRS‐R decline. Initial baseline NfL values showed a strong correlation (r = −0.53, p < .001) to ALSFRS‐R decline.