Post Hoc Responder Analyses of SHP465 Mixed Amphetamine Salts Extended-Release Among Adults With Attention-Deficit/Hyperactivity Disorder

In adults with attention-deficit/hyperactivity disorder (ADHD), SHP465 mixed amphetamine salts (MAS) extended-release reduced ADHD-Rating Scale-IV total score (ADHD-RS-IV-TS) significantly more than placebo. These post hoc analyses examine SHP465 MAS response rates in 2 studies of adults with ADHD. In a 7-week dose-optimization study, adults (baseline ADHD-RS-IV-TS ≥24) were randomized to SHP465 MAS (12.5–75 mg) or placebo. In a 6-week fixed-dose study, adults (baseline ADHD-RS-IV-TS ≥32) were randomized to SHP465 MAS (25, 50, or 75 mg) or placebo. Response was assessed using 3 definitions (Definition 1: ≥30% ADHD-RS-IV-TS reduction + Clinical Global Impressions–Improvement [CGI-I] rating of 1 or 2; Definition 2: ≥50% ADHD-RS-IV-TS reduction + CGI-I rating of 1 or 2; Definition 3: ADHD-RS-IV-TS ≤18). Kaplan-Meier analyses assessed time to response. The dose-optimization and fixed-dose studies, respectively, included 132 and 103 placebo and 136 and 302 SHP465 MAS participants. Percentages (95% CI) of participants meeting response criteria (placebo vs SHP465 MAS) at final treatment week in the dose-optimization and fixed-dose studies, respectively, were 31.6% (21.1%, 42.0%) vs 66.0% (56.4%, 75.5%) and 28.3% (16.9%, 39.7%) vs 72.7% (67.0%, 78.5%) for Definition 1; 27.6% (17.6%, 37.7%) vs 47.9% (37.8%, 58.0%) and 16.7% (7.2%, 26.1%) vs 60.6% (54.3%, 66.9%) for Definition 2; and 30.3% (19.9%, 40.6%) vs 54.3% (44.2%, 64.3%) and 18.3% (8.5%, 28.1%) vs 52.6% (46.2%, 59.0%) for Definition 3. Time to response favored SHP465 MAS in both studies (all nominal log-rank P < 0.0001). These post hoc analyses indicate that SHP465 MAS is associated with greater response rates than placebo.