Objective: To evaluate the efficacy and safety of a 16-hr multilayer-release methylphenidate (PRC-063) in a community-based adult ADHD population. Method: In a double-blind study, 375 participants were randomized to one of four fixed doses of PRC-063 or placebo. The primary outcome was the ADHD-Rating Scale-5 (RS). The first 50% of double-blind completers were invited to participate in a 6-month dose-optimized open-label study to assess response and safety. Results: In total, 333 participants completed the double-blind trial; 184 entered the open-label study. PRC-063 produced greater symptom reduction in ADHD-RS-5 total score from baseline compared with placebo in the double-blind study (least-square [LS] mean = -4.7 [-7.7, -1.6], p = .003). The most frequent adverse events were headache, insomnia, and decreased appetite. No significant sleep quality impact was observed (p = .123). Significant improvements in ADHD-RS-5 scores from baseline continued through the open-label study (p < .0001), coincident with dose optimization. Conclusion: PRC-063 was well tolerated and significantly improved ADHD symptomatology in adults.
Keywords: adult ADHD; attention deficit hyperactivity disorder; methylphenidate; stimulant.