Response and remission rates varied substantially when researchers applied different symptom cutoffs to SHP465 trials. The terms should be read as operational definitions within the analysis, not as interchangeable evidence of recovery.
This post hoc report used two placebo-controlled adult ADHD trials of extended-release mixed amphetamine salts: a seven-week dose-optimization study and a six-week fixed-dose study. It examined both percentage symptom reductions and absolute endpoint scores.
Response definitions included a 30% or 50% symptom reduction combined with favorable clinician improvement, or an ADHD Rating Scale IV total at or below 18. Remission used a stricter total-score cutoff of 12.
In the dose-optimization study, 66.0% of active-treatment participants met the 30%-plus-global-improvement definition, while 47.9% met the 50% version. The remission cutoff was met by 37.2%. Corresponding placebo rates were lower.
A person can improve greatly from a high baseline while retaining substantial symptoms. Conversely, someone closer to a cutoff can cross it with a smaller change. Relative response and absolute symptom status therefore measure different aspects of outcome.
Time-to-event comparisons nominally favored active treatment, but these analyses were not prospectively powered and their p values were descriptive. The authors also noted that the specified response and remission criteria had not been linked here to particular functional improvements.
The industry-funded analysis does not show sustained recovery after treatment ends or establish normalized functioning in every setting. Clear reporting identifies the scale, cutoff, follow-up period and comparator. It does not treat a rating threshold as a drug concentration, diagnostic assay or measure of individual impairment.
See a separate adult SHP465 trial.
Post hoc Responder and Remission Analyses from Two Studies of SHP465 Mixed Amphetamine Salts Extended-Release Among Adults with Attention-Deficit/Hyperactivity Disorder. doi:10.1089/cap.2020.0012.