Topical oxybutynin antiperspirant for axillary hyperhidrosis: a phase IIb PROBE design clinical trial (TODAY trial).

Background: Primary hyperhidrosis is a chronic condition with limited therapeutic options. Objectives: To evaluate the impact of 10% oxybutynin spray on axillary hyperhidrosis, considering both its local and systemic effects, in terms of Hyperhidrosis Disease Severity Scale (HDSS) outcomes for hyperhidrosis of the axilla and eight additional sites. Methods: Prospective phase II PROBE design trial. Adult patients with axillary hyperhidrosis were randomized to receive a 10% oxybutynin topical spray, oral oxybutynin, or placebo spray for 35 days. Efficacy was evaluated on day 35 using the HDSS and a hyperhidrosis-specific quality-of-life (QoL) assessment questionnaire. Results: 17 patients were randomized. No significant differences were observed in HDSS outcomes from baseline to day 35 in any of the three groups (2.5 [2 - 4], 4 [3 - 4], 3.5 [3 - 4], p= 0.207), although a trend to improvement was noted in both treatment groups. Significant improvement in the QoL questionnaire was observed from baseline to day 35 in the oxybutynin spray group (pre-intervention QoL: 78.5 [70 - 96] and post-intervention QoL: 38.5 [32 - 67], p = 0.031). Conclusions: No differences were observed in the primary outcome. A significant improvement from baseline to day 35 was observed in the QoL questionnaire score for the oxybutynin spray group.