RLS-1496 cut actinic keratosis lesion counts by 49% in four weeks

By Tom Whitfield

Rubedo Life Sciences reported a 49% mean reduction in actinic keratosis lesion counts after four weeks of treatment with investigational RLS-1496. The early study enrolled patients with multiple clinically identifiable lesions in defined treatment areas and compared treated skin with untreated skin, according to company co-founder and chief scientific officer Marco Quarta, Ph.D.

In an interview with Clinical Leader Executive Editor Abby Proch, Quarta framed the result as early evidence for selectively targeting pathological senescent cells. The interview did not report the actinic keratosis sample size, dosing schedule, statistical analysis or peer-reviewed results, leaving the finding preliminary.

Why did Rubedo start with skin diseases?

Atopic dermatitis and actinic keratosis offered complementary tests of RLS-1496. Atopic dermatitis is a chronic inflammatory disease that can probe inflammatory signaling, barrier function and tissue health; actinic keratosis is a precancerous condition associated with cumulative sun damage and typical of an older population.

Quarta cited emerging research suggesting atopic dermatitis can accelerate skin aging. He also noted that localized, visible actinic keratosis can make patients look older, while skin can be photographed and biopsied more easily than many organs.

What did the early studies show?

In the atopic dermatitis study, participants had clinically evaluable disease, allowing changes in symptoms, inflammation and underlying tissue biology to be assessed. Rubedo reported clinical improvement, changes in inflammatory and aging-associated biomarkers, and a statistically significant 2.1-year mean reduction in measured skin epigenetic age across 11 paired samples.

Local skin and blood inflammatory biomarkers also declined. Histology showed a 10% increase in type III collagen fibers, while spatial transcriptomics and proteomics found increased expression across multiple collagen types.

The findings extend beyond a conventional inflammation readout, but they do not establish reversal of biological aging. Quarta said: “These findings suggest biological effects extending beyond conventional measures of inflammation, although they do not yet establish a true reversal of biological aging.”

How did patient selection and biomarkers shape the evidence?

Rubedo selected patients with clearly defined, measurable disease and tried to minimize complicating factors. It recognizes that severity, age, prior treatments, cumulative sun exposure and underlying inflammatory activity can influence outcomes, while cellular senescence itself varies among individuals and tissues.

Clinical assessments, tissue biopsies and molecular analyses will help identify biological characteristics associated with treatment response and refine selection in later trials. The tracked markers include glutathione peroxidase 4 target engagement, senescence-associated signaling, inflammatory pathways, extracellular-matrix remodeling and epigenetic markers of biological aging.

RLS-1496 is designed to modulate glutathione peroxidase 4, or GPX4, selectively target pathological senescent cells and support restoration of surrounding tissue. Quarta said the latter is mediated by induction of nuclear factor erythroid 2-related factor 2, or NRF2, producing a “redox reset” in stressed cells around senescent cells.

Can lower inflammation explain the aging signal?

The working hypothesis links pathological senescent cells to both chronic disease and age-related tissue dysfunction through persistent inflammatory signaling, oxidative stress and impaired cellular function. Rubedo is testing whether clinical improvement travels with molecular signatures of senescence and biological aging, rather than treating the two outcomes as interchangeable.

Quarta acknowledged the limit: “However, correlation does not establish causation.” Longitudinal studies must determine whether target engagement, cellular changes and clinical outcomes share one mechanism. Until then, biomarker changes alone cannot establish benefit, so Rubedo is matching them with less itching and inflammation, lesion clearance and improved skin health.

How did the team separate disease improvement from aging?

For atopic dermatitis, Rubedo prioritized safety, tolerability and improvement in inflammatory skin disease. It separately analyzed photoaged skin outside the lesions, examining DNA methylation patterns, senescence-associated signatures and collagen production as molecular and structural features associated with biological aging.

The separation relied on epigenetic clocks, spatial transcriptomics, histology and extracellular-matrix remodeling markers. Together with the 2.1-year epigenetic-age reduction and 10% type III collagen increase, these analyses suggest effects beyond inflammation, although longer follow-up and independent tissue-function measures remain necessary.

What does the broader development strategy require?

Rubedo aims to establish cellular senescence as a therapeutically actionable driver of chronic and age-related disease. The company cites early findings in atopic dermatitis, psoriasis, actinic keratosis and photoaged skin to support further investigation, and it is expanding into androgenetic alopecia, where cellular aging and tissue dysfunction may contribute to disease biology.

Rubedo’s platform identifies pathological cells involved in aging, including senescent-like cells, and develops small molecules designed to target them across its pipeline. The company calls this class of medicines SenoAdaptive and aims to address cellular dysfunction rather than only downstream symptoms.

Dermatology allows direct evaluation of efficacy, target engagement and tissue biology while limiting systemic drug exposure. In the atopic dermatitis study, circulating inflammatory biomarkers fell after topical treatment despite undetectable systemic drug exposure in most subjects, a preliminary finding that raises questions about the broader effects of local senescence modulation.

Beyond dermatology, Quarta is interested in diseases in which pathological senescent cells and chronic inflammatory signaling have meaningful roles. Systemic development would require disease-relevant biology, appropriate pharmacology, systemic safety and meaningful therapeutic benefit.

Quarta said: “Any expansion into systemic indications would require additional evidence of disease-relevant biology, appropriate pharmacology, systemic safety, and meaningful therapeutic benefit.” Longer studies must establish whether the current target-engagement and clinical signals persist before broader development.

Quarta earned a master’s degree in biotechnology and a Ph.D. in neuroscience, then completed postdoctoral training in aging and stem-cell biology with Thomas Rando at Stanford University School of Medicine. He later directed translational aging and regenerative-medicine research at Stanford/VA Hospital Palo Alto.

He also co-founded the nonprofit Phaedon Institute, which brings experts and institutions together to accelerate clinical translation of aging research and longevity medicine. Rubedo’s stated mission is to develop treatments for chronic age-related diseases and extend healthspan.

The next milestone is longer follow-up with independent tissue-function measures to determine whether the epigenetic and collagen signals persist and translate into clinical benefit. That evidence, rather than biomarker movement alone, will determine whether Rubedo can move from skin studies toward systemic SenoAdaptive medicines.