Arbaclofen extended-release tablets for spasticity in multiple sclerosis: open-label extension study.

Area of Science:

• Neurology
• Pharmacology
• Clinical Trials

Background:

• Baclofen, a GABA-B agonist, treats multiple sclerosis spasticity but has dosing and tolerability issues.
• Arbaclofen, the R-enantiomer of baclofen, offers higher receptor specificity and potency.
• Arbaclofen extended-release (ER) demonstrated favorable safety and efficacy in Phase 3 trials.

Purpose of the Study:

• To evaluate the long-term safety and efficacy of arbaclofen ER in adult patients with multiple sclerosis-related spasticity.
• To assess adverse events, tolerability, and sustained spasticity reduction over a 52-week period.

Main Methods:

• A 52-week, open-label, multicenter extension study of a Phase 3 trial.
• Adults with moderate to severe spasticity received arbaclofen ER titrated up to 80 mg/day.
• Safety and efficacy were assessed using clinical scales, including the Numeric-transformed Modified Ashworth Scale (NTMAS) and patient-reported outcomes.

Main Results:

• 218 of 323 patients (67.5%) completed the 1-year study.
• Most patients (74.0%) reached an 80 mg/day maintenance dose.
• 86.1% experienced treatment-emergent adverse events, mostly mild-moderate, with common events including urinary tract disorder, muscle weakness, and asthenia.
• 14.9% discontinued due to adverse events.
• Sustained improvement in multiple sclerosis-related spasticity was observed.

Conclusions:

• Arbaclofen ER (up to 80 mg/day) was well-tolerated and effective for long-term management of multiple sclerosis spasticity in adults.
• The treatment provided sustained reduction in spasticity symptoms over 52 weeks.
• Arbaclofen ER represents a viable therapeutic option for patients needing chronic spasticity management.