Osmotica sinks 40% after multiple sclerosis drug fails to beat placebo

Osmotica Pharmaceuticals is trading lower after the company announced last night that arbaclofen did not demonstrate superiority to placebo in a study. The shares in early trading are down 40%, or $2.71, to $4.03. OS440-3004 was a double-blind placebo-controlled study in which multiple sclerosis patients with documented muscular spasticity in any limb received placebo, 40 mg arbaclofen per day, or 80 mg arbaclofen per day. The co-primary efficacy measures assessed in this study were Clinical Global Impression of Change and the change from baseline in the Total Numeric modified Ashworth Scale. Arbaclofen did not demonstrate superiority to placebo as measured by the CGIC; however, a statistically significant improvement in spasticity relative to placebo was demonstrated as measured by the TNmAS for 40 mg and 80 mg per day, respectively, Osmotica said. It added, “Upon preliminary review, it appears that CGIC failed to recognize the improvement demonstrated by the TNmAS. However, the CGIC values indicated both treatment groups improved from baseline. Further, the preliminary results appear to identify a dose-response relationship between the two strengths with the 80 mg dose exhibiting a stronger signal of efficacy as assessed by the spasticity scale. Though arbaclofen 80 mg per day had a higher discontinuation rate in the study, the safety and tolerability profile was in line with previously reported results, most notably a somnolence incidence of 9.5% and 14.5% for the 40-mg and 80-mg treatment arms, respectively, compared to 9.6% for the placebo treatment arm. Somnolence is one of the most frequently reported dose-limiting adverse events associated with baclofen treatment today. Further evaluation and additional analyses are ongoing, and we anticipate providing a further update once complete.” The company went on, “We continue to believe that arbaclofen is a promising option for the treatment of spasticity in MS patients. While the topline results are disappointing, spasticity in MS remains an important unmet medical need, and, subject to completion of the data analysis and regulatory considerations we intend to continue to pursue submission of an arbaclofen NDA for review to the FDA although our timeline could now extend past 2019.”

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