- Clinical validation of stem cell reactivation approach positions Pelage as leader in regenerative medicine and aging
LOS ANGELES — Pelage Pharmaceuticals, a clinical-stage regenerative medicine company, today announced positive results from its Phase 2a clinical trial of PP405 — a topical therapy for androgenetic alopecia advancing through the FDA clinical development pathway. PP405 is designed to reactivate dormant hair follicle stem cells, offering a potential first-in-class approach for both men and women experiencing hair loss.
“These early clinical results reinforce the potential of our approach to go beyond slowing the hair loss process and directly drive hair follicle regeneration.”
Hair loss affects more than 80% of men and 40% of women over their lifetimes, yet treatment options are limited. The global market for hair loss prevention products reached $23.6 billion in 2021 and is projected to grow to $31.5 billion by 2028, underscoring both the vast scale of the affected population and the demand for effective solutions. PP405 directly addresses this gap with a novel topical non-invasive regenerative approach.
Unlike currently available treatments that primarily target secondary causes of hair loss such as hormones, PP405 acts on the primary biological pathway driving natural hair follicle cycles. This innovative mechanism targeting hair follicle stem cells, which are retained even in balding scalps, positions PP405 as an option suitable for patients traditionally underserved by current treatments, including women and individuals with longstanding hair loss.
The Phase 2a randomized controlled trial enrolled a total of 78 men and women with androgenetic alopecia, representing a diverse range of skin phototypes and hair textures. The subjects applied PP405 or a placebo on their scalp once daily for 4 weeks and were followed out to 12 weeks. The study met its primary safety endpoint and secondary pharmacokinetic endpoint: the drug was well tolerated with no systemic absorption of PP405 detected in the blood, underscoring a robust safety profile. Exploratory endpoints assessed early signs of new hair growth.
Preliminary results from one month of treatment showed a rapid and statistically significant clinical response. At week eight, only four weeks after the completion of treatment in men with a higher degree of hair loss, 31% of those treated with PP405 exhibited a greater than 20% increase in hair density, compared to 0% of patients responding in the placebo group. Typically, visible hair regrowth requires 6–12 months of continuous therapy, suggesting PP405 may yield a more rapid clinical response than current treatments. Particularly striking was the finding that unlike existing drugs that primarily slow hair loss or support hair growth from already-active follicles, PP405 induced new hair growth from follicles where no hair was previously present — offering early validation of its regenerative potential.
Established research has shown that in patients with pattern hair loss, bald areas of the scalp retain dormant hair follicles and stem cells, which have effectively fallen asleep due to a combination of age, stress, genetics, and environmental factors. By activating these follicular stem cells, PP405 has the potential to regrow hair in areas of thinning or balding, setting it apart in a market where most options offer maintenance, not restoration.
“These early clinical results reinforce the potential of our approach to go beyond slowing the hair loss process and directly drive hair follicle regeneration,” said Christina Weng, M.D., Chief Medical Officer of Pelage Pharmaceuticals. “We see this as a milestone that expands the possibilities of regenerative medicine. As we advance into the next stage of clinical development, our focus remains on delivering a science-driven solution that works for everyone.”
Pelage’s clinical development strategy follows the FDA regulatory pathway, underscoring the company’s commitment to rigorous science and patient safety. Following the randomized portion of the clinical study, subjects who received placebo were eligible to enroll in a three-month open-label safety extension to assess long-term safety. Pelage expects to initiate Phase 3 studies in 2026 designed to further evaluate the safety and efficacy of PP405 in men and women.
“Despite affecting millions, hair loss has seen remarkably little progress in clinical research,” said Dr. Arash Mostaghimi, Vice Chair of Clinical Trials and Innovation at Brigham and Women’s Hospital and Pelage advisory board member. “What’s compelling about PP405 is that it brings scientific rigor to a space that’s needed it for decades. A well-tolerated, topically delivered therapy that shows measurable biological activity this early is rare. This could reshape how we think about clinical progress in hair growth.”
Pelage’s technology is rooted in pioneering stem cell research out of UCLA and is guided by a leadership team and advisory board with deep expertise in dermatology and regenerative biology from Mass General Brigham and other leading institutions. The company is backed by a premier investor syndicate led by GV (Google Ventures) — which spearheaded Pelage’s series A and Series A-1 financings — with participation from Main Street Advisors, Visionary Ventures, and YK Bioventures.
About Pelage Pharmaceuticals
Pelage Pharmaceuticals is a clinical-stage regenerative medicine company developing novel treatments for hair loss including androgenetic alopecia and chemotherapy-induced alopecia. With a focus on metabolism and stem cell biology, Pelage is advancing a new class of treatments designed to reactivate dormant hair follicle stem cells and restore the body’s ability to naturally grow hair. Its lead program, PP405, is currently in Phase 2a clinical trials. Through its rigorous scientific foundation, Pelage is pioneering first-in-class hair growth solutions for people of all hair types experiencing hair loss.
About PP405
PP405 is a novel, non-invasive, topical small molecule designed to reactivate dormant hair follicle stem cells and restart hair growth. Through a regenerative medicine approach, the treatment focuses on addressing the metabolic processes that regulate the activation and inactivation phases of hair follicle stem cells. Early results from a Phase 1 trial show that PP405 was well-tolerated and demonstrated statistically significant activation of hair follicle stem cells. In 2018, Pelage Pharmaceuticals licensed the intellectual property to PP405 and related topical small molecules from UCLA. Information on the Phase 2a study can be found on ClinicalTrials.gov.
