Arbaclofen Extended-Release Effective, Tolerable in Treating MS Spasticity

Investigators sought to determine the safety and efficacy of twice-daily dosing of arbaclofen ER in patients with spasticity due to multiple sclerosis.

The following article is part of conference coverage from the 2019 Annual Meeting of the Consortium of Multiple Sclerosis Centers , in Seattle, Washington. MPR‘s staff will be reporting breaking news associated with research conducted by leading experts in neurology. Check back for the latest news from CMSC 2019.

SEATTLE – Twice-daily arbaclofen extended-release has demonstrated efficacy and tolerability in individuals with multiple sclerosis (MS) who suffer from spasticity. This research was recently presented at the 33rd Annual Meeting of the Consortium of Multiple Sclerosis Centers, held May 28 to June 1, 2019, in Seattle, Washington.

This double-blind, multicenter, parallel-group study included 341 individuals (13 were removed after study end when an audit uncovered irregularities) randomly assigned 1:1:1 to placebo, arbaclofen extended-release 20 mg twice daily, or baclofen 20 mg 4 times daily. Of the participants, 57.5% had relapsing-remitting MS, 38.4% had secondary progressive MS, 2.6% had primary progressive MS, and 0.9% had progressive relapsing MS. A 2-week titrated dose preceded 12 weeks of maintenance treatment. The changes from baseline through maintenance treatment in Clinician Global Impression of Change and Total Numeric-transformed Modified Ashworth Scale for the most affected limb (TNmAS-MAL) constituted the primary endpoints.

Mean baseline TNmAS-MAL was 7.93 in participants receiving arbaclofen extended-release, 7.75 in those receiving baclofen, and 7.55 in those receiving placebo. The mean reduction in TNmAS-MAL from baseline through the end of the maintenance period was greater in participants receiving arbaclofen than in the placebo group (least-squares mean, -2.90 vs -1.95; P =.0006). Arbaclofen also showed significant improvement in Clinical Global Impression of Change vs placebo (least-squares mean, 1.00 vs 0.52; P =.0004). Arbaclofen was also associated with a significantly higher change in the MS Spasticity Scale compared with placebo (-30.1 vs -16.7; P =.0229). Arbaclofen did not differ significantly from baclofen in any of these metrics, though it was associated with less reported dizziness or drowsiness. Treatment-emergent adverse events (largely somnolence, asthenia, and muscle weakness) were reported by 57.3% (n=63) of participants on arbaclofen, 72.6% (n=82) on baclofen, and 50.0% (n=59) on placebo.

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The study researchers conclude that “[twice]-daily arbaclofen [extended-release] was efficacious and well-tolerated in subjects with spasticity.”

All study authors report financial associations with pharmaceutical companies. For a full list of disclosures, visit the reference.

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Kantor D, deVries T, Dentiste A, Handiwala L, Jacobs D. Arbaclofen extended-release tablets versus placebo or baclofen for the treatment of spasticity in subjects with multiple sclerosis (study OS440-3002). Poster presentation at: 33rd Annual Meeting of the Consortium of Multiple Sclerosis Centers; May 28-June 1, 2019; Seattle, WA. Abstract SXM07.

This article originally appeared on Neurology Advisor