Arbaclofen Extended-Release Reduces Multiple Sclerosis-Related Spasticity

Multiple sclerosis brain MRI
Multiple sclerosis brain MRI
Presenting at CMSC 2021, researchers evaluated the efficacy and safety of arbaclofen extended-release tablets in patients with multiple sclerosis-related spasticity.
The following article is part of conference coverage from the 2021 Annual Meeting of the Consortium of Multiple Sclerosis Centers (CMSC), held October 25-28 2021, in Orlando, Florida. Neurology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in neurology. Check back for the latest news from the 2021 CMSC Annual Meeting.

A 12-week course of arbaclofen extended-release tablets significantly reduced spasticity related to multiple sclerosis (MS) when compared with placebo, according to research presented at the 2021 Annual Meeting of the Consortium of Multiple Sclerosis Centers (CMSC), held October 25 to 28, 2021 in Orlando, Florida.

In the multicenter, phase 3 study, a total of 536 patients with MS-related spasticity were randomly assigned to either twice-daily 40 mg or 80 mg arbaclofen extended-release or placebo for 12 weeks. Researchers examined the change from baseline to 12 weeks in the Total Numeric-Transformed Modified Ashworth Scale in the Most Affected Limb (TNmAS-MAL) score as well as the Clinical Global Impress of Change (CGIC) score. Additionally, the investigators assessed changes in the TNmAS score of total limbs (TNmAS-TL), Expanded Disability Status Scale (EDSS) score, and Patient Global Impress of Change (PGIC) score.

At the 12-week follow-up, the least squares (LS) mean change from baseline to 12 weeks in the TNmAS-MAL score was -1.67 (95% CI, -1.97 to -1.36) in the 40 mg arbaclofen extended-release arm vs -1.28 (95% CI, -1.57 to -0.99) in the placebo group (LS mean difference, -0.39; P <.05). While there were improvements in mean CGIC scores for the 40 mg arbaclofen extended-release and placebo groups, no significant difference was observed between these arms (LS mean difference, -0.10; P =.43).

The researchers noted that there were significant improvements across all 3 treatment groups regarding the mean change from baseline in the TNmAS-TL and PGIC scores. Likewise, they reported that the mean EDSS scores were stable during the study period.

In terms of safety, all treatment-emergent adverse events were considered mild to moderate in severity and occurred in 77.1% of patients treated with 40 mg arbaclofen, 83.2% of patients treated with 80 mg arbaclofen, and 71.3% of patients treated with placebo. Based on the safety analysis, the researchers concluded that twice-daily arbaclofen “appeared to have an acceptable safety profile” in patients with MS-related spasticity.

Disclosure: Multiple authors declared affiliations with the pharmaceutical industry. Please refer to the original article for a full list of disclosures.

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Kantor D, Hunter SF, Jaros M, et al. Arbaclofen extended-release for the treatment of spasticity in multiple sclerosis: A randomized, multicenter, placebo-controlled clinical study (Study OS440-3004). Presented at: CMSC 202; October 25-28, 2021; Orlando, Florida. Abstract SXM01.