Supernus Pharmaceuticals reports its phase IIa US clinical trial of SPN-812 in adults for the treatment of attention deficit hyperactivity disorder (ADHD) met the primary endpoints of safety and tolerability and showed statistically significant median reduction versus placebo in both investigator-rated and patient-rated ADHD symptom scores. The trial was a randomized, double-blind, placebo-controlled trial in 52 adults with a current diagnosis of ADHD (26 subjects per treatment group).

Patients in the active arm were administered SPN-812 at a single-dose level three times a day over five weeks, after a one-week titration phase. The primary endpoint was safety, and SPN-812 was shown to be safe and well tolerated by patients. The secondary endpoints included: the efficacy of SPN-812 as measured by Total ADHD Symptom Score on the Conners’ Adult ADHD Rating Scale, or CAARS, a commonly-used measurement for ADHD in adults, as rated by each of the investigators and the patients; and the effectiveness of SPN-812 when compared to placebo as determined by changes in the Clinical Global Impressions-Improvement, or CGI-I, score.

Subjects in the active group achieved overall significant median reductions from baseline in investigator-rated CAARS total ADHD symptom scores by study end, -11.5 points vs. -6.0 for placebo (p=0.0414) and in self-rated CAARS total symptom scores by study end, -10.5 points vs. -1.0 for placebo (p=0.0349). With respect to the secondary endpoint of CGI-I scores, patients exhibited a trend, although not statistically significant, toward larger median reductions in scores from baseline vs. placebo.

“Because this proof-of-concept study was not designed to show a definitive statistical significant separation from placebo on the primary efficacy outcome, we are extremely pleased to have observed such a strong signal in such a small study,” said Paolo Baroldi, senior vice president and chief medical officer of Supernus.