PP405: Research & Studies

Research Overview#

PP405 development is based on foundational research from UCLA demonstrating that hair follicle stem cell activation is driven by lactate metabolism. The clinical program has progressed through Phase 1 (safety) and Phase 2a (proof of concept) with promising results, though peer-reviewed publications of clinical data are pending.

Preclinical Foundation: Flores et al. (PMID 28812580)#

The 2017 Nature Cell Biology paper by Flores et al. from the Lowry and Christofk laboratories at UCLA established the scientific rationale for PP405. Key discoveries:

• Hair follicle stem cells in the telogen (resting) phase rely on mitochondrial oxidative phosphorylation
• Activation into the anagen (growth) phase is associated with a metabolic switch to glycolysis and increased lactate production
• Genetic deletion of LDHA (lactate dehydrogenase A) prevented hair follicle stem cell activation
• Genetic deletion of MPC1 accelerated hair follicle stem cell activation
• Topical application of small molecule MPC inhibitors (UK5099) induced the hair cycle in mouse models

This study provided the target validation and proof of concept that led to PP405 development.

Phase 1 Clinical Trial#

Pelage presented late-breaking data at the AAD 2024 Annual Meeting demonstrating that PP405 activated human hair follicle stem cells both ex vivo and in the Phase 1 clinical study, with no systemic absorption detected.

Phase 2a Clinical Trial (NCT06393452)#

The Phase 2a trial was a randomized, multicenter, double-blind, vehicle-controlled study:

The responder analysis focused on men with a higher degree of hair loss. The finding of new hair growth in areas with no previous hair was particularly notable, as it suggests regenerative rather than merely preventive activity.

Evidence Quality Assessment#

Research Evidence Context#

PP405 belongs to the Skin category of research peptides. The research evidence for PP405 spans multiple study types and endpoints. Researchers should evaluate the strength of evidence based on study design, sample size, and publication status when drawing conclusions about efficacy and safety.

Key Clinical Studies#

The following studies provide the clinical evidence base for PP405:

Lactate dehydrogenase activity drives hair follicle stem cell activation#

Authors: Flores A, Schell J, Krall AS, et al. (2017) — Nature Cell Biology

Foundational study from UCLA demonstrating that hair follicle stem cells rely on lactate production via LDHA for activation, and that MPC1 deletion or pharmacological MPC inhibition accelerates the hair cycle.

Key Findings:

• Hair follicle stem cells use glycolytic metabolism and produce more lactate than other epidermal cells
• Deletion of LDHA prevented hair follicle stem cell activation
• MPC1 deletion accelerated hair follicle stem cell activation and the hair cycle
• Small molecule MPC inhibitors topically induced the hair cycle in mice

Limitations: Mouse model study. The specific compound tested was UK5099, not PP405. Translation from mouse hair cycle to human androgenetic alopecia required subsequent clinical validation.

Phase 2a Randomized, Double-Blind, Vehicle-Controlled Study of PP405 in Adults With Androgenetic Alopecia#

Authors: Pelage Pharmaceuticals (company press release) (2025) — ClinicalTrials.gov (NCT06393452)

Phase 2a randomized controlled trial evaluating 0.05% PP405 topical gel versus vehicle in 78 patients with androgenetic alopecia. Once-daily application for 4 weeks with follow-up to 12 weeks.

Key Findings:

• Met primary safety endpoint with no serious adverse events
• No systemic absorption of PP405 detected in blood plasma
• 31% of men with advanced hair loss achieved greater than 20% increase in hair density at 8 weeks versus 0% in placebo
• Evidence of new hair growth in previously bald areas suggesting regenerative potential

Limitations: Results reported via press release only, not yet published in a peer- reviewed journal. Small sample size (78 patients). Short treatment duration (4 weeks). Responder analysis focused on a subgroup.

Evidence Quality Assessment#

The overall evidence level for PP405 is classified as low. Available research includes limited clinical data, typically from small or early-phase studies. More rigorous clinical trials are needed to draw definitive conclusions.

Research Gaps and Future Directions#

The following gaps in the current evidence base for PP405 have been identified:

• Phase 3 randomized controlled trial data (planned for 2026)
• Long-term efficacy and safety with chronic use
• Dose-response relationship and optimal concentration
• Comparison with existing therapies (minoxidil, finasteride) in head-to-head trials
• Mechanism confirmation in human scalp tissue (beyond ex vivo studies)
• Efficacy in female pattern hair loss specifically
• Combination therapy potential with existing treatments
• Peer-reviewed publication of Phase 2a clinical trial results

Addressing these research gaps will be important for establishing a more complete understanding of PP405's therapeutic potential and safety profile.

Related Reading#

• PP405 overview and research guide
• PP405 dosing protocols
• PP405 molecular structure