Two‐week prospective observational study of 5% sofpironium bromide gel in Japanese patients with primary axillary hyperhidrosis

In 2020, 5% sofpironium bromide (ECCLOCK ® ) gel (hereinafter referred to as sofpironium) was approved in Japan for the topical treatment of primary axillary hyperhidrosis. A phase III study of sofpironium demonstrated the efficacy and safety of sofpironium; however, no study has assessed its early efficacy at <6 weeks after starting treatment. Therefore, to assess the earlier effectiveness of sofpironium, we conducted a 2‐week, single‐center, exploratory, prospective, observational study in Japanese patients with primary axillary hyperhidrosis. Patients aged ≥20 years and satisfying with a Hyperhidrosis Disease Severity Scale (HDSS) score of 3 or 4 at baseline were eligible for the study. The primary endpoint for the effectiveness was change in the proportion of patients with a HDSS score of 1, 2, 3, or 4 during the 2‐week study period. In 80 patients included in the full analysis set (FAS), there were more women than men (93.8% vs. 6.3%), and the mean age (±standard deviation [SD]) was 33.3 ± 9.4 years. In the FAS, the proportion of patients with a HDSS score of 1 or 2 was 55.0% on day 7, and statistically significant changes were observed after day 3 compared to baseline ( p  < 0.05). Mean HDSS scores (±SD) were significantly decreased from baseline value of 3.5 ± 0.5 to 2.4 ± 0.9 on day 7 ( p  < 0.001). The median period for sofpironium treatment to achieve a HDSS score of 1 or 2 for a continuous 2 days was 6 days (95% confidence interval, 4–8). Safety was evaluated in 92 patients in the safety analysis set, and no adverse events were reported during the study period of 2 weeks. These results suggest that after 1‐week treatment with sofpironium for patients with a HDSS score of 3 or 4, approximately 50% of the patients can achieve a HDSS score of 1 or 2, which is a clinically significant improvement for the patients.