FDA Will Review Arbaclofen ER, Potential Oral Therapy for MS Spasticity

The U.S. Food and Drug Administration (FDA) has agreed to review  Osmotica Pharmaceuticals‘ amended request for the approval of arbaclofen extended release (ER) tablets to treat spasticity in people with multiple sclerosis (MS), the company announced.

The regulatory agency found that the new drug application addressed all issues raised in a July 2016 action letter response to the company’s original NDA. An FDA decision is expected by Dec. 29, 2020.

Arbaclofen ER (brand name, Ontinua ER) is an extended release formulation of arbaclofen, a compound similar to the muscle relaxant baclofen that is approved to treat spasticity (muscle stiffness) in people with MS, spinal cord injuries, or other disorders involving the spinal cord.

This extended release formulation, which is based on Osmotica’s proprietary Osmodex drug delivery technology, allows arbaclofen to be slowly released over longer periods of time, potentially reducing dosing frequency and undesirable side effects.

The amended application is supported by data from the Phase 3 OS440-3004 trial (NCT03290131) and its open-label, long-term extension study (NCT03319732), which investigated the safety and effectiveness of arbaclofen ER at alleviating spasticity in MS patients.

Findings from OS440-3004 showed that when given as a daily 40 mg or 80 mg tablet, arbaclofen ER lowered patients’ TNmAS-MAL scores, a well-established measure of muscle spasticity, from the study’s start to day 84 compared with placebo.

Most patients who participated and completed OS440-3004 enrolled in its long-term extension study, OS440-3005, and completed one year of treatment with the highest arbaclofen ER dose, 80 mg daily.

Results from the extension study showed that patients taking arbaclofen ER tablets daily continued with improvements in their TNmAS-MAL scores, demonstrating the medication’s long-term effectiveness at alleviating spasticity. During this study, arbaclofen ER was also found to be safe and generally well-tolerated.

Findings from OS440-3004 and OS440-3005 were also consistent with data from an earlier Phase 3 trial of arbaclofen ER, called OS440-3002 (NCT01743651), which showed that when given at a daily dose of 40 mg the therapy was more effective at lowering patients’ TNmAS-MAL scores than placebo, and similarly effective to an 80 mg dose of baclofen.

Patients given baclofen also experienced more frequent side effects, including dizziness and drowsiness, than those in the trial group using arbaclofen ER.