Attention-Deficit Hyperactivity Disorder Severity Reduced With SDX/d-MPH

Attention-deficit hyperactivity disorder (ADHD) severity in children was significantly reduced when treated with serdexmethylphenidate/dexmethylphenidate (SDX/d-MPH), according to research presented at Psych Congress 2022 held from September 17 to 20, 2022, in New Orleans, Louisiana.

The once-daily treatment, SDX/d-MPH, contains 70% SDX — a novel prodrug of d-MPH hydrochloride — and 30% d-MPH.

In the study, researchers investigated changes in ADHD severity in children between the ages of 6 and 12 years following treatment with SDX/d-MPH in a laboratory classroom. The primary outcome of the study was a mean change from baseline in Swanson, Kotkin, Agler, M-Flynn, and Pelham-Combined (SKAMP-C) scores averaged over the laboratory classroom day (0.5-13 hours postdose). In children with ADHD, SKAMP measures subjective impairment of classroom behaviors via a 13-item scale that includes subcategories of attention, deportment, quality of work, and compliance. The researchers explained SKAMP-C score is calculated by adding the rating values for each of the 13 items.

An exploratory outcome evaluating weekly changes in ADHD severity was measured with The Conners 3rd Edition-Parent (C3P) score. The C3P score derives from Conners 3-P, a 43-item report by parents and caregivers that evaluates inattention, hyperactivity/impulsivity, learning problems, executive functioning, aggression, and peer relationships, the researchers explained.

The double-blind, dose-optimized, multicenter, randomized, placebo-controlled laboratory classroom study (ClinicalTrials.gov Identifier: NCT03292952) comprised 150 children (9.6±1.6 years of age; 38.7% girls; 73.3% not Hispanic or Latino, 50.7% White, 37.3% Black, respectively) titrated during a 3-week open-label, dose-optimization phase based on tolerability and individual response (SDX/d-MPH dose of 26.1/5.2 mg, 39.2/7.8 mg, or 52.3/10.4 mg, respectively). Participants then received once-daily SDX/d-MPH or placebo during the 7-day double-blind treatment period.

Researchers found significant improvement in the SKAMP-C scores with SDX/d-MPH vs placebo (least-squares mean difference [LSMD], 5.4; 95% CI, -7.1 to -3.7; P <.001), which indicates fewer symptoms with SDX/d-MPH. Mean C3P scores indicating changes in ADHD severity showed significant improvement from baseline throughout the dose-optimization phase for each subscale (P <.001).

In the treatment phase, researchers observed that C3P scores showed significant improvement from baseline for SDX/d-MPH vs placebo in the subscales of:  

• Executive functioning (LSMD, -9.0; 95% CI, -13.3 to -4.7; P <.001),
• Hyperactivity/impulsivity (LSMD, -9.9; 95% CI, -14.4 to -5.3; P <.001),
• Inattention (LSMD, -11.2; 95% CI, -15.7 to -6.7; P <.001), and
• Learning problems (LSMD, -5.4; 95% CI, -8.9 to -1.8; P =.003).

In subscales of peer relations and defiance/aggression, there was no observed significant difference. Researchers noted that SDX/d-MPH had no concerning safety signals.

They concluded that “SDX/d-MPH demonstrated significant reductions in ADHD severity in children based on the C3P scores.”

Disclosure: This research was supported by KemPharm, Inc. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.