Osmotica Amends NDA for Arbaclofen ER to Treat MS Spasticity

Osmotica Pharmaceuticals has submitted an amended new drug application (NDA) to the U.S. Food and Drug Administration (FDA) requesting the approval of arbaclofen extended release (ER) tablets for the treatment of spasticity in people with multiple sclerosis (MS).

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

The therapy is based on Osmotica’s proprietary Osmodex drug delivery technology, which allows the production of tablets containing one or more ingredients for immediate, controlled, delayed, or extended release.

This extended release formulation of arbaclofen releases the medication’s active ingredient gradually over longer periods of time, potentially allowing for less-frequent dosing and likely reducing the risk of side effects.

“We are excited to have resubmitted our NDA for arbaclofen ER, our novel treatment, using the Osmodex technology, for MS spasticity,” Brian Markison, CEO of Osmotica Pharmaceuticals, said in a press release.

The company’s NDA resubmission was supported by data from two trials — the Phase 3 OS440-3004 study (NCT03290131) and its open-label, long-term extension OS440-3005 (NCT03319732) — that are both part of arbaclofen ER’s clinical developmental program, one of the largest programs focused on MS spasticity.  

During OS440-3004, MS patients with spasticity were assigned randomly to receive one of two doses (40 or 80 mg) of arbaclofen ER tablets, or a placebo, twice daily for three months.

After completing this study, patients had the option to enroll in OS440-3005 and continue treatment with arbaclofen ER — administered at the highest tolerated dose (up to 80 mg daily) — for up to one year. Patients who were not in the Phase 3 trial also could enroll in this open-label extension trial.

Findings from OS440-3004 showed that both doses of arbaclofen ER led to significant improvements in patients’ Total Numeric modified Ashworth Scale of the most affected limb (TNmAS-MAL) scores — a well-established measure of muscle spasticity — from the study’s start to day 84, compared to the placebo.

Although the mean Clinical Global Impression of Change (CGIC) score — a parameter that reflects a physician’s assessment of a patient’s well-being — in those receiving arbaclofen ER was not significantly better compared to the placebo, patients treated with arbaclofen ER did not see their scores worsen after treatment.

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

Those receiving arbaclofen ER at a daily dose of 80 mg experienced an overall improvement in their TNmAS scores for up to one year, which demonstrated the treatment’s sustained effectiveness. Arbaclofen ER also was found to be safe and well-tolerated during the study.

Results from another Phase 3 trial, called OS440-3002 (NCT01743651), also demonstrated that a daily 40 mg dose of arbaclofen ER led to a significantly more pronounced reduction in the TNmAS-MAL and improvements in CGIC than an 80 mg dose of baclofen. Side effects were less frequent with arbaclofen ER compared with baclofen.

“The safety and efficacy results from these studies, together with the entire data package from our clinical development program, supports the clinical significance of arbaclofen ER as a potential treatment for MS spasticity. We look forward to working with the FDA during the course of its review,” Markison said.