Randomized, Double-Blind, Placebo-Controlled Trial on the Efficacy, Safety and Tolerability of Modified-Release Methylphenidate (MPH-MR) in Chinese Children and Adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD).

Background and objectives: The efficacy and safety of modified-release methylphenidate (MPH-MR) in the treatment of attention-deficit/hyperactivity disorder (ADHD) have been shown in both pediatric and adult Caucasian patients. The objective of this study was to assess the efficacy and safety of MPH-MR in Chinese children and adolescents with ADHD.

Methods: MICCA was a randomized, double-blind, placebo-controlled trial conducted at 19 sites in China from September 2018 to July 2021. The study enrolled children and adolescents aged 6 to < 18 years with a primary diagnosis of ADHD according to the Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-5). Patients were randomized 1:1 to once-daily MPH-MR (10-60 mg) or placebo. The study included an up-titration phase of up to 5 weeks and a dose maintenance phase of 4 weeks. The primary efficacy endpoint was the change in the ADHD Rating Scale-IV (ADHD-RS-IV) total score from baseline to the end of the maintenance phase (EoM). Secondary endpoints included the change from baseline to EoM in Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P) total score, and Clinical Global Impression-Improvement (CGI-I) scores at EoM. Safety assessments included treatment-emergent adverse events (TEAEs) and vital signs.

Results: A total of 221 patients were randomized (MPH-MR: n = 110; placebo: n = 111). The change in the ADHD-RS-IV total score from baseline to EoM was significantly greater for MPH-MR versus placebo, with a least squares (LS) mean (95% confidence interval [CI]) treatment difference of - 4.6 (- 6.92, - 2.30) (p < 0.001). The mean (95% CI) treatment difference for the WFIRS-P total score change from baseline to EoM also significantly favored MPH-MR over placebo (- 6.46 [- 10.57, - 2.34]; p = 0.002). The CGI-I score at EoM was significantly lower in the MPH-MR group compared to the placebo group (2.2 vs 2.5; p = 0.002). Treatment-emergent adverse events were reported for 74 (67.3%) patients in the MPH-MR group and 55 (49.1%) patients in the placebo group. Most TEAEs were mild to moderate in severity. The most common TEAEs for MPH-MR were decreased appetite, nausea and upper respiratory tract infection. Treatment-emergent adverse events leading to study drug discontinuation/study withdrawal were reported in 4 (3.6%) patients in the MPH-MR group and 1 (0.9%) patient in the placebo group. No clinically relevant changes in vital signs were observed during the study.

Conclusions: Modified-release methylphenidate was superior to placebo in improving ADHD symptoms and functioning in Chinese pediatric patients with ADHD. Modified-release methylphenidate had a good safety and tolerability profile. Trial Registration http://www.chinadrugtrials.org.cn/ Identifier: CTR20180056 (registered on 21 May 2018).