Supernus Pharma Announces Data from Phase III PROSPER Study on Oxtellar XR Showed Potential Boost to Tolerability

Supernus Pharmaceuticals, Inc.

, a specialty pharmaceutical company, today announced the publication of the Prospective, Randomized Study of Oxcarbazepine extended release in Subjects with Partial Epilepsy Refractory (PROSPER) data on Oxtellar XR. Results of this Phase III pivotal trial will appear in the upcoming March issue of Acta Neurologica Scandinavica, Volume 129, Issue 3, pages 143–153 and is available online at http://onlinelibrary.wiley.com/doi/10.1111/ane.12207/abstract. “We are pleased to see the PROSPER study results published in a renowned peer-reviewed journal in neurology such as Acta Neurologica Scandinavica. This represents the first publication for Supernus in such a journal, allowing physicians to have access to the study results. The publication highlights the important role Oxtellar XR can play in improving the lives of patients with epilepsy. These results mirror those seen in numerous patient cases since the launch of our product,” said Jack A. Khattar, President and CEO of Supernus. The PROSPER study evaluated and demonstrated the safety and efficacy of our novel once-daily 1200 mg and 2400 mg doses of Oxtellar XR when added to 1-3 concomitant antiepileptic drugs in adults with refractory partial-onset seizures, with or without secondary generalization. Oxtellar XR also showed the potential to improve tolerability when compared to what is known about the immediate release versions of oxcarbazepine. This was the Phase III pivotal study that formed the basis of approval by the FDA. It was a randomized, double-blind, parallel-group, placebo controlled study conducted at 88 sites in eight countries throughout North America and Eastern Europe. The primary efficacy endpoint was median percent reduction from baseline in monthly (28-day) seizure frequency for the 16-week double-blind treatment period in the intent-to-treat (ITT) population with analyzable seizure data. Other efficacy analyses included proportion of patients with ≥ 50% seizure reduction, proportion of patients that are seizure free, and the relationship between clinical response and plasma concentration. Median percent reduction was significant for once-daily Oxtellar XR compared to placebo at 2400 mg (P = 0.003). In the placebo, 1200mg/day and 2400mg/day treatment groups, respectively, responder rates were 28.1%, 36.1% (P = 0.08), and 40.7% (P = 0.02); 16-week seizure-free rates in a pragmatic ITT analysis were 3.3%, 4.9% (P = 0.59), and 11.4% (P = 0.008). Post hoc analyses demonstrated that both Oxtellar XR dosages were significantly superior to placebo in median percent seizure reduction (placebo: −13.3%; 1200 mg: −34.5%, P = 0.02; 2400 mg: −52.7%, P = 0.006) in the North American study site cluster. A concentration–response analysis also supported a clinically meaningful effect for 1200 mg. Adverse event frequency was consistent with a pharmacokinetic profile of Oxtellar XR producing lower peak plasma concentrations versus oxcarbazepine immediate-release. Once-daily dosing was not associated with any new safety signals.