Phase III P301 trial of SPN 810 in patients with ADHD, did not meet its primary endpoint.- Supernus Pharma

Supernus Pharmaceuticals, Inc. reported financial results for the third quarter of 2019, results from the Phase III P301 trial for SPN 810 and associated Company developments.

Phase III P301 trial in patients 6 to 11 years old did not meet its primary endpoint. The study was a randomized, double blind, placebo controlled, multicenter, parallel group clinical trial in patients diagnosed with ADHD. Patients receiving SPN 810 36mg showed a median percent reduction of 58.6% in the average weekly frequency of impulsive aggression episodes from baseline that was not statistically significant (p= 0.092) compared to placebo. These results are based on the combined analysis of data from stages 1 and 2 in the study.

In stage 1 (interim analysis stage), the median percent reduction was 60%, which was statistically significant (p= 0.029) compared to placebo. However, in stage 2 of the study, post the interim analysis, the increase in variability in the 36mg treatment arm seems to have adversely impacted the results in the combined analysis.

The median percent reduction in frequency of IA behavior in this Phase III study is consistent with the range of percent improvement in the retrospective modified aggression scale (58% - 62%) seen in the two positive treatment arms in the Phase IIb study. The Company will continue its analysis of the results to better understand the reasons behind the increased variability in the 36mg treatment arm in the P301 study. Overall, the trial exhibited favorable tolerability and safety profiles with low incidence of adverse events (AEs) across all doses. AEs were mild leading to low discontinuation rates of 0%, 7% and 5% for the 18mg, 36mg and combined treatment arms, respectively.