A Prospective, Nonrandomized, Open‐Label Study of the Efficacy and Safety of OnabotulinumtoxinA in Adolescents with Primary Axillary Hyperhidrosis

OBJECTIVE: To evaluate the efficacy and safety of onabotulinumtoxinA in adolescents with primary axillary hyperhidrosis. METHODS: This 52‐week, multicenter, nonrandomized, open‐label study was conducted in 141 adolescents ages 12 to 17 years with severe primary axillary hyperhidrosis. Patients could receive up to six treatments with onabotulinumtoxinA (50 U per axilla), with re‐treatment occurring no sooner than 8 weeks after the prior treatment cycle and no later than 44 weeks after the initial treatment cycle. The primary efficacy measure was treatment response, based on self‐assessed hyperhidrosis severity following the first two treatments using the 4‐point Hyperhidrosis Disease Severity Scale (HDSS). Other efficacy measures included spontaneous resting sweat production and health outcomes. RESULTS: Fifty‐six (38.9%) participants underwent one treatment, 59 (41.0%) underwent two, 20 (13.9%) underwent three, 6 (4.2%) underwent four, and 3 (2.1%) underwent five. OnabotulinumtoxinA significantly improved HDSS scores and decreased sweat production compared with treatment cycle baselines. Seventy‐nine patients (54.9%) responded to treatment based on HDSS criteria. From 56.6% to 72.3% of patients experienced a two‐grade or more improvement at 4 and 8 weeks after each of the first two treatments. The majority (79.4%–93.2%) had a 75% or greater reduction in sweat production at week 4 (treatments 1–3). The median duration of effect for responders ranged from 134 to 152 days. Using quality of life measures, health outcomes improved markedly. Eight patients (5.6%) had mild or moderate treatment‐related adverse events. No unexpected safety signals were observed in this study. Neutralizing antibodies to onabotulinumtoxinA did not develop. CONCLUSION: OnabotulinumtoxinA injections provided beneficial effects in adolescents with primary axillary hyperhidrosis.