Supernus Pharmaceuticals Faces Setback with SPN-820 Study Results

On Tuesday, Supernus Pharmaceuticals, Inc. (NASDAQ: SUPN) announced the topline results from its Phase 2b study of SPN-820, a treatment aimed at adults suffering from treatment-resistant depression (TRD).

The study aimed to assess the effectiveness of SPN-820 in improving depression symptoms but unfortunately did not show significant improvement on its primary endpoint. The primary measure used was the Montgomery-Åsberg Depression Rating Scale (MADRS) total score, where no statistical difference was found between the SPN-820 group and those receiving a placebo after four weeks.

Additionally, the study’s secondary endpoints also did not reflect a notable difference between SPN-820 and the placebo, leaving the results disappointing for stakeholders. This lack of effectiveness raises concerns about the future of SPN-820 as a viable treatment option for TRD.

Despite the disappointing results, the safety profile of SPN-820 remained consistent with findings from earlier clinical trials, where few adverse events were reported.

Jack Khattar, the President and CEO of Supernus, expressed disappointment regarding the trial outcomes, stating, “We are disappointed that the trial did not meet its primary endpoint in this patient population. We will continue to analyze these data and discuss the future of the program with our development partner, Navitor Pharmaceuticals.”

In a related note, earlier this month, Supernus Pharmaceuticals received approval from the FDA for ONAPGO (apomorphine hydrochloride) injection, which marks the first and only subcutaneous apomorphine infusion device designed for treating motor fluctuations in adults with advanced Parkinson’s disease. ONAPGO is expected to be available in the second quarter of 2025.

In previous exploratory open-label studies, SPN-820 had shown promise, demonstrating a rapid and substantial decrease in depressive symptoms in adults with major depressive disorder, with a favorable safety profile.

The market reacted negatively to the trial results, with Supernus Pharmaceuticals’ stock falling by 14.10% to $34.20 during Wednesday’s trading session.

Investors and analysts will be closely watching Supernus as they evaluate their next steps following the recent study results.

Supernus, Pharmaceuticals, SPN-820