Long-Term (1 Year) Safety and Efficacy of Methylphenidate Modified-Release Long-Acting Formulation (MPH-LA) in Adults with Attention-Deficit Hyperactivity Disorder: A 26-Week, Flexible-Dose, Open-Label Extension to a 40-Week, Double-Blind, Randomised, Placebo-Controlled Core Study

INTRODUCTION: Previously, in a 40-week, randomised, double-blind, placebo-controlled core study comprising three phases (9-week dose confirmation, 5-week open-label dose optimisation and 6-month maintenance of effect) in adults with attention-deficit/hyperactivity disorder (ADHD), methylphenidate modified-release long-acting formulation (MPH-LA) at 40–80 mg/day controlled ADHD symptoms as well as decreased functional impairment with a good tolerability profile (NCT01259492). Here, we report the long-term efficacy and safety from a 26-week, open-label extension phase of the same study (NCT01338818). METHODS: Patients in the extension study (n = 298) initiated treatment with MPH-LA (20 mg/day), up-titrated in increments of 20 mg/week to reach individual patient’s daily optimal dose of 40–80 mg. Adverse events (AEs) and serious adverse events (SAEs) were reported at the end of extension study for events monitored from (1) maintenance of effect phase baseline (core study; 12 months) and (2) extension study baseline (6 months). Mean changes in DSM-IV ADHD Rating Scale (DSM-IV ADHD RS) and Sheehan Disability Scale (SDS) total scores are reported for both the timelines. Efficacy was also evaluated using clinician-rated instruments, namely Clinical Global Impression-Improvement Scale (CGI-I) and Clinical Global Impression-Severity Scale (CGI-S). RESULTS: No unexpected AEs were reported in the extension study. Incidence of SAEs reported during 6 months and 12 months were similar (0.7 %), and no deaths were reported. No SAEs were considered attributable to the drug at the end of 12 months. There were no reports of patients with QT, QTcB or QTcF >500 ms. The mean improvement in DSM-IV ADHD RS and SDS total scores at the end of 12 months were 0.9 and 1.4 points, respectively; and at the end of 6 months were 7.2 and 4.8, respectively. The proportion of patients with improvement in CGI-S scale was 31.4 % and 52.1 % at the end of 12 and 6 months, respectively. Overall, 69.4 % of patients showed clinical improvement in CGI-I scale at the end of 6 months. CONCLUSIONS: In adult patients with ADHD, use of MPH-LA up to 1 year continued to be well tolerated while maintaining the clinical efficacy.