A topical treatment for androgenetic alopecia, the most common form of hair loss, has shown encouraging early results in a Phase 2a clinical trial, according to biotechnology company Pelage Pharmaceuticals.  

The investigational drug, PP405, is being evaluated in a randomised, double-blind, placebo-controlled study involving 78 adult participants with varying degrees of pattern hair loss. The study is designed to assess the safety, pharmacokinetics, and preliminary efficacy of the compound over several months.  

Unlike traditional therapies that aim to slow or stop hair loss, PP405 is intended to reactivate dormant hair follicle stem cells by inhibiting the mitochondrial pyruvate carrier (MPC) – a metabolic checkpoint that keeps these cells in a resting state. By disrupting MPC activity, the drug is believed to kick-start stem cell activation and hair regrowth.  

According to preliminary data released by Pelage, approximately 31% of male participants treated with PP405 experienced at least a 20% increase in hair density at eight weeks, compared to 0% in the placebo group. Some individuals reportedly showed visible regrowth in areas of the scalp that were previously bald.  

No serious or unexpected adverse events have been reported. The company also stated that systemic drug exposure was undetectable in blood samples, suggesting the topical formulation remains localised to the scalp.  

The study includes a 28-day double-blind treatment period followed by a 3-month open-label extension, in which all participants receive PP405. Final data collection is expected by the end of 2025, and Pelage has indicated plans to begin Phase 3 studies in 2026.