The parallel studies enrolled 1,465 men with androgenetic alopecia (AGA) across 50 sites in Europe and the U.S., demonstrating statistically significant and clinically meaningful improvements in hair growth compared with placebo, the Dublin-based company said.
One trial reported a 539% relative improvement in target-area hair count (TAHC) over six months, while the second showed a 168% gain versus placebo. Cosmo CEO Giovanni Di Napoli clarified that the difference is “entirely due to baseline hair counts, not differences in drug performance,” explaining that absolute hair count gains were similar across both groups.
“This could mark the first potential innovation in over 30 years for male hair loss,” Cosmo added.
Following the announcement, Cosmo shares surged 20%.
Experts hailed the results as a potential game-changer. “These data have the potential to redefine how dermatologists treat androgenetic alopecia worldwide,” said Maria Hordinsky, M.D., from the University of Minnesota’s Department of Dermatology.
Clascoterone, commercially known as Winlevi, was originally FDA-approved in 2020 for acne through Cosmo’s subsidiary, Cassiopea. It has become the leading branded topical acne treatment in the U.S., with 1.4 million prescriptions since its 2021 launch.
The first-in-class topical androgen receptor inhibitor works by blocking dihydrotestosterone (DHT) directly at the hair follicle, without systemic absorption, addressing the root cause of male-pattern hair loss while avoiding the risks associated with oral therapies.
“For decades, patients faced limited efficacy or safety concerns with systemic treatments, often choosing not to treat at all,” Hordinsky added. “These findings suggest clascoterone 5% topical solution can deliver measurable regrowth with minimal systemic exposure.”
Patient-reported outcomes further supported the efficacy data, with one study achieving statistical significance and the other showing a positive trend. Treatment-emergent adverse events were comparable to placebo and mostly unrelated to clascoterone.
Cosmo plans to complete a 12-month safety and durability study in spring 2026, followed by parallel submissions to the FDA and European Medicines Agency.
According to the company, of 166 million men in the U.S., 65 million have AGA, including 16 million who have received treatment and 27 million actively seeking therapy. Cosmo estimates the U.S. market opportunity at $20 billion.
“Our U.S. market research shows enormous, underserved demand,” Di Napoli said. “These compelling Phase 3 data give us full confidence ahead of regulatory submissions.”
Cosmo, which focuses on MedTech AI, dermatology, gastrointestinal diseases, and contract development and manufacturing (CDMO), reported 2024 revenue of €266 million ($310 million), a 186% increase from the previous year.
