SHP465 Amphetamine Salts Improved Problem Solving, Attention in Adults with ADHD

Timothy WIgal, PhD

The use of SHP465 amphetamine salts (MAS) is associated with significantly greater short-term improvements in problem solving and attention compared with placebo in adults with attention-deficit hyperactivity disorder (ADHD), according to a randomized, cross-over study.

SHP465 amphetamine salts (MAS) are comprised of equal parts of dextroamphetamine sulfate, amphetamine sulfate, dextroamphetamine saccharate, and amphetamine aspartate monohydrate.

“The primary finding of this study is that SHP465 MAS produced significantly greater improvement in Permanent Product Measure of Performance (PERMP) total score than placebo in adults with ADHD in the adult workplace environment,” according to study researcher Timothy WIgal, PhD, and colleagues.

Researchers randomized 86 ADHD patients in a simulated adult workplace setting to either 50 mg immediate-release or extended-release SHP465 MAS, 75 mg immediate-release or extended-release SHP465 MAS, 25 mg immediate-release MAS, or placebo. The primary study endpoint was comprised of treatment efficacy at the end of each 7-day treatment period, assessed by the sum of the number of attempted problems as well as the number of correctly answered problems on the PERMP. Efficacy was evaluated at 16 hours following treatment.

Additionally, researchers evaluated total scores on the counselor observations during Time Segment Rating System (Co-ADHD-RS TSRS) and the 18-item ADHD-SRS, which assessed symptom frequency and severity, respectively. Other endpoints included safety and tolerability, such as treatment-emergent adverse events (TEAEs) and vital signs.

Compared with placebo, treatment with 50 mg and 75 mg SHP465 MAS was associated with significantly greater PERMP total scores averaged across all assessment periods (18.38 [95% CI 11.28-25.47]; P <.0001). In addition, 50 mg and 75 mg SHP465 MAS demonstrated greater PERMP total score associations compared with placebo at each post-dose assessment (P <.02 for all). Immediate-release MAS also demonstrated superiority over placebo for the primary efficacy endpoint when averaged across all assessments (nominal P = .0001).

Scores on the Co-ADHD-RS TSRS nominally favored immediate-release MAS vs placebo across all average post-dose cycles (P = .0010). For ADHD-SRS total score, the least squares mean treatment differences favored 50 mg and 75 mg SHP465 MAS over immediate-release MAS at 16.5 hours following treatment (P = .0029).

More patients in the treatment groups reported TEAEs compared with placebo; however, no statistical analysis was performed to determine significant differences between the groups. Insomnia (36.5%) and anorexia (21.2%) were the most frequently reported TEAEs among patients treated with SHP465 MAS.

The investigators of this study noted that their findings are limited in that they do not provide insight into long-term effects of treatment, considering the study ran for only 3 weeks. Additionally, since this study was performed in an adult setting, the findings may not generalize to the pediatric ADHD population.

“It is important to note that the duration of effect reported in the current study, and in all research settings, is not necessarily the duration that will be observed in clinical practice,” concluded the study researchers. “Overall, the risks and benefits of extended-duration stimulants in adults with ADHD should be assessed by physicians for each patient in terms of the need for longer duration of efficacy vs tolerability.”

The study, “A Randomized, Double-Blind Study of SHP465 Mixed Amphetamine Salts Extended-Release in Adults With ADHD Using a Simulated Adult Workplace Design,” was published in Postgraduate Medicine.