GPX4 Modulator Shows Early Promise in First-in-Human Study

Key Takeaways

• RLS-1496, a first-in-class GPX4 modulator, demonstrated early biologic activity across multiple dermatologic indications in a Phase 1 trial.
• Dose-dependent target engagement and reductions in senescent cells were observed, with accompanying improvements in inflammatory and histologic markers.
• The therapy introduces a novel “cellular rejuvenation” approach, with potential applications spanning inflammatory disease, precancerous lesions, and skin aging.

A novel topical therapy targeting cellular senescence showed early biologic activity across multiple dermatologic conditions in a Phase 1 clinical trial, according to data presented by Frederick Beddingfield III, MD, PhD, FAAD, at the Dermatology Innovation Forum during the American Academy of Dermatology (AAD) 2026 Annual Meeting.

RLS-1496, developed by Rubedo Life Sciences, is a first-in-class glutathione peroxidase 4 (GPX4) modulator designed to selectively target senescent cells. These cells accumulate with age and contribute to chronic inflammation and tissue dysfunction.

“It alters senescent cells. It kills certain senescent cells and then alters the cells around them to put them into a more homeostatic balance,” Dr. Beddingfield told Practical Dermatology. 

The Phase 1 program evaluated RLS-1496 across a “basket” of indications, including psoriasis, atopic dermatitis, actinic keratosis, and photodamaged skin. This design enabled simultaneous assessment of pharmacologic activity across disease states.

“We decided to study a basket of indications,” Dr. Beddingfield said. “The beauty of that is you can explore the drug and understand how it works in multiple indications, and if you start to see similar patterns across these different indications, you get a sense of what the drug is doing and what we should be exploring next in a Phase 2 study and toward an approval pathway.”

In psoriasis, a clear dose-response relationship was observed, with higher concentrations associated with increased target engagement and reduction in senescent cells. Histologic improvements were also reported, including an approximately 20% reduction in epidermal thickness after 4 weeks, alongside reductions in inflammatory cytokines such as IL-19. 

Early atopic dermatitis data suggested enhanced drug penetration and activity, consistent with impaired barrier function in this population. Clinical signals included a ≥4-point reduction in itch in 25% of treated patients, with no comparable responses observed in vehicle-treated patients. 

Across studies, RLS-1496 was well tolerated, with minimal local irritation and negligible systemic exposure.

“We rarely even see this drug in the blood; it is generally below the level that we can detect,” Dr. Beddingfield said. 

Additional exploratory findings included increased collagen production and reduced collagen degradation markers in aging skin. Ongoing analyses aim to assess epigenetic “biological age” changes in treated skin.

“Are we actually turning back the clock?” Dr. Beddingfield said. 

The company is also advancing an oral formulation based on the same mechanism, with the topical program informing systemic development. While early and limited to short-duration exposure, these findings highlight a potential new therapeutic approach centered on modulating aging-associated cellular pathways rather than targeting single inflammatory mediators.