Pelage Pharmaceuticals: Pioneering Stem Cell Therapy for Hair Loss

Pelage Pharmaceuticals, a Los Angeles-based biotechnology company, closed a $120 million Series B financing in October 2025 to advance its novel approach to treating androgenetic alopecia through hair follicle stem cell reactivation.

Addressing an Unmet Medical Need

Androgenetic alopecia affects more than 80% of men and 40% of women throughout their lifetimes, yet treatment options remain limited. Only two FDA-approved monotherapies exist—minoxidil and finasteride—and neither has been updated in decades.

Finasteride works by blocking hormone conversion, while minoxidil's exact mechanism remains unclear. However, neither treatment directly targets the biological pathways that control hair follicle stem cell activation, leaving a significant gap in therapeutic options.

A Stem Cell-Based Approach

Pelage's lead program, PP405, is a first-in-class topical small molecule designed to reactivate dormant hair follicle stem cells through metabolic activation. The therapy promotes lactate production, which acts as a metabolic signal that shifts hair follicle stem cells from a dormant to an active state.

This approach is particularly promising because hair follicle stem cells remain present even in balding areas. Rather than simply slowing hair loss progression, PP405 aims to restart the body's natural ability to grow hair by targeting these dormant stem cells.

The therapy is grounded in over ten years of laboratory research from UCLA into the metabolic activation of hair follicle stem cells.

Phase 2a Clinical Results

In July 2025, Pelage reported positive interim results from a randomized, placebo-controlled Phase 2a trial evaluating PP405 in 78 adult patients with androgenetic alopecia. The study included men and women aged 18 to 55 years, representing diverse skin phototypes and hair textures.

Participants received either 0.05% PP405 topical gel or placebo once daily for four weeks and were followed for up to 12 weeks. The trial met its primary safety endpoint, with PP405 demonstrating excellent tolerability and no systemic absorption detected in blood plasma.

While designed primarily to assess safety, the preliminary efficacy results exceeded expectations. At Week 8—four weeks after completion of dosing—31% of men with moderate to severe hair loss who received PP405 experienced a greater than 20% increase in hair density, compared to 0% in the placebo group. This rapid response is notable, as visible hair regrowth typically requires 6-12 months of continuous therapy with current treatments.

PP405 also induced new hair growth from follicles where no hair was previously present, suggesting the therapy can go beyond slowing hair loss and directly drive hair follicle regeneration.

Following the randomized controlled phase, participants in the placebo group were eligible to enroll in a three-month open-label extension to assess long-term safety, which is now complete. The company plans to present the full dataset at a medical meeting in 2026.

Leadership Team

Pelage is led by a team with expertise in biotechnology and regenerative medicine:

• Daniel Gil, Ph.D., Chief Executive Officer: Gil leads the company's mission to deliver a clinically-tested hair loss treatment grounded in innovative science.
• William Lowry, Ph.D., Co-Founder and President: A UCLA faculty member, Lowry conducted the pioneering research into metabolic activation of hair follicle stem cells that forms the foundation of Pelage's approach.
• Christina Weng, MD, Chief Medical Officer: Weng oversees the company's clinical development programs.

The company's board includes Cathy Friedman of GV, who serves as Chair of the Board, and Richard Heyman, Ph.D., of ARCH Venture Partners.

Funding Details

The $120 million Series B financing was co-led by ARCH Venture Partners and GV (Google Ventures), with participation from existing investors Main Street Advisors, Visionary Ventures, and YK Bioventures. The capital will enable Pelage to advance PP405 through Phase 3 clinical trials and toward potential regulatory approval.

Pipeline & Next Steps

Pelage's pipeline focuses exclusively on PP405 for androgenetic alopecia. Key milestones include:

• 2026: Initiation of Phase 3 clinical trials
• 2026: Presentation of full Phase 2a dataset at a medical meeting

The company aims to develop PP405 as an accessible treatment option for all people experiencing hair loss, regardless of hair type or texture.

Market Potential

The androgenetic alopecia market represents a multi-billion dollar opportunity. Pelage's competitive advantage lies in its novel mechanism targeting hair follicle stem cell reactivation rather than secondary symptoms. If Phase 3 trials confirm the safety and efficacy signals observed in Phase 2a, PP405 could become the first new FDA-approved treatment for androgenetic alopecia in decades.

The company's success will depend on continued demonstration of safety and efficacy in larger, longer-duration trials, as well as navigating the regulatory approval process. However, the early regenerative signals and rapid response observed to date suggest PP405 has the potential to provide a meaningful new option for millions of people experiencing hair loss worldwide.