Efficacy of Viloxazine ER (Qelbree) for ADHD in Adults Based on Prior Stimulant Exposure

Introduction Although many patients respond equally well to both stimulant and nonstimulant medications for ADHD, some patients respond preferentially to one class over another. Currently, most patients receive a stimulant as first-line therapy; however, nonstimulants present fewer obstacles for prescribers and patients and have low abuse/misuse potential. Still, when patients have suboptimal response to stimulants, physicians may be reticent to switch to a nonstimulant medication due to concerns that the nonstimulant response will be less robust or less preferable for patients. Viloxazine ER (viloxazine extended-release capsules; Qelbree®) is a nonstimulant, FDA-approved treatment for ADHD in children (≥6 years) and adults. This post-hoc analysis of adult Phase 3 trial data (NCT04016779) evaluates response to viloxazine ER (200-600 mg/day) based on whether or not patients reported a history of previous stimulant use. Methods For patients randomized to viloxazine in this Phase 3, double-blind, placebo-controlled trial, the change from baseline (CFB) in Adult ADHD Investigator Symptom Rating Scale (AISRS) score (primary trial outcome) was analyzed for prior stimulant users vs. nonusers using MMRM. Prior stimulant use was based on patient-reported medication history recorded upon enrollment. Subjects using stimulants at the time of study screening were required to undergo a ≥1-week washout period prior to randomization. Results Of 372 patients treated, 189 received viloxazine ER. Of the patients who received viloxazine ER, 40 reported prior stimulant use and 149 did not. Mean (SD) baseline AISRS scores for prior stimulant users and nonusers were 38.5 (7.40) and 38.3 (6.44), respectively. Response appeared similar in both patient groups. At Week 6/End of Study (EOS) the least squares (LS) mean (SE) CFB AISRS scores for prior stimulant users and nonusers were -15.8 (2.51) and -15.6 (1.08)]; treatment difference -0.2 (2.41); P=0.93. Though not significant, prior stimulant users showed a larger magnitude of improvement on the AISRS at early timepoints compared to those without prior stimulant use [Week 1, LS mean (SE) CFB AISRS Total scores: -9.2 (1.40) vs. -6.8 (0.70), respectively; treatment difference: -2.4 (1.56); P=0.12.] Conclusions A history of prior stimulant use did not appear to influence the magnitude of ADHD symptom response to viloxazine ER in this preliminary analysis of Phase 3 trial data in adults. Rather, subjects with prior stimulant use showed numerically larger reductions in AISRS scores at early timepoints that were not significantly different from those without prior stimulant use. Additional analysis should be undertaken to evaluate patterns of response in the pediatric population. Funding Supernus Pharmaceuticals, Inc.