Marco Quarta is co-founder and Chief Scientific Officer of Rubedo Life Sciences, a precision-therapeutics company developing medicines that target the pathological cell states that drive age-associated disease. Marco's first appearance on the show was three years ago, in February 2023 (Episode 35), when Rubedo was a much earlier-stage company committed to the then-contrarian premise that "the senescent cell" is not a single entity but a heterogeneous family of cell states that needs to be deconvoluted at the single-cell level. In March 2026, Rubedo reported preliminary Phase 1b/2a clinical data for its lead candidate, RLS-1496, a first-in-class topical GPX4 modulator. Marco returns to the show to discuss what survived contact with human biology. In this episode, Chris and Marco unpack the readout from Rubedo's basket trial across four skin indications — psoriasis, atopic dermatitis, actinic keratosis, and photoaged skin — and the biology that underlies it. RLS-1496 came clean on safety in all four indications, with significant efficacy signals despite small patient numbers and short (20–30 day) treatment courses. More provocatively, the clinical and translational data have pushed Marco to redefine what kind of drug this actually is. Rather than a next-generation senolytic, GPX4 modulation appears to act as a state-gating intervention: it triggers ferroptosis in deeply senescent cells that have already crossed a redox threshold, while inducing a hormetic "redox reset" in stressed-but-recoverable cells that restores them to a healthier state. Marco proposes a new category to capture this dual action — adaptive senotherapeutics, or senoadaptive drugs — distinct from senolytics and senomorphics. The conversation traces the arc from Rubedo's founding thesis to a clinically validated platform (ALEMBIC, the AI-enabled single-cell multiomics engine that surfaced GPX4 as a target), through the strategic logic of leading with skin, into the broader question every longevity-biotech founder eventually has to answer: when does a disease-by-disease franchise become a credible preventive geroscience platform? Marco lays out the GLP-1 analogy explicitly — an anchor indication and a label-expansion roadmap that could carry GPX4 modulation from dermatology into respiratory, neurodegenerative, and metabolic disease, and ultimately into the use case where biomarkers of cellular senescence flag patients for therapy decades before disease becomes clinically apparent. The Finer Details: How Marco's 2023 contrarian view — that "senescent cells" hide a tissue- and state-specific reality — has been reinforced by the clinic, and how Rubedo's framing has shifted from "targeting senescent cells" to "targeting pathological cell states"The biology of GPX4 as a lipid-peroxidation gatekeeper, why senescent cells have intrinsic vulnerabilities (p16, p21, CDK4/6 inhibition) that make them ferroptosis-sensitive, and how Rubedo's approach differs from oncology-focused GPX4 programs at Takeda and othersThe "senoadaptive" mechanism — RLS-1496 eliminates GPX4-dependent senescent cells via ferroptosis while triggering NRF2/Keap1-driven redox reset, autophagy, and epigenetic remodeling in recoverable cells, restoring tissue trajectory from degenerative to regenerativeWhy Rubedo led with skin: clean regulatory path, accessible tissue, the ability to read out aging biology anddisease in the same trial, and a label-expansion runway into systemic indicationsPhase 1b (Europe) and Phase 2a (US) basket-trial results across psoriasis, atopic dermatitis, photoaged skin, and actinic keratosis: clean safety in 4/4 indications and significant efficacy signals — itch reduction in atopic dermatitis, decreased lesional thickness in psoriasis, target-engagement-correlated clinical improvement in photoaged skinThe richness of the translational dataset: biopsies, tape-stripping, spatial transcriptomics, proteomics, multiplex histomics, plasma biomarkers — all feeding back into ALEMBIC to refine the platformWhy actinic keratosis is the most strategically important indication — an age-related, chronic-inflammatory, precancerous condition where Rubedo can simultaneously test disease modification and biological-age reversalThe Rubedo–Beiersdorf partnership and the cosmetic vertical as a parallel commercial axisPipeline beyond skin: targeting aberrant basaloid stem cells in IPF and other pulmonary indications using different modalities (prodrugs, PROTACs, ADCs) to achieve cell-state selectivityThe longer-arc vision: senescence biomarkers as a "prediabetes-style" early signal, with senoadaptive drugs deployed decades before disease — and what a GLP-1-scale franchise might look like for GPX4 modulation Quotes: "There is not such a thing as a senescent cell — like there is not a cancer cell. And that was the initial idea. I'm glad that over time the field evolved. Now this is an accepted concept in the senotherapeutic space." "We are really talking about a dual function of RLS-1496 that can modulate the cell state depending on the adaptive response. That's why we call this — de facto — a new class of senotherapeutics. We call them adaptive senotherapeutics, or senoadaptive drugs — not a senolytic or a senomorphic, but working by modulating the cell state." "The best animal model for human therapies is human. As much as you can do preclinical work in animal models, it's always an approximation. We were able to test this directly in patients for safety, and in 4 out of 4 indications, we didn't have any safety signal." "Imagine you're taking care of a growing tree, and this tree has some dead leaves and some are a little bit stressed. If you shake the tree, the dead leaves will fall; the healthy leaves will not, because they're healthy and they resist the shake. But that shake actually gives the stressed leaves space and breathing room, and helps them to regain vitality. That's a little bit what GPX4 modulation does." "Senotherapeutics is a large, growing field — an untapped therapeutic opportunity. There is no such thing as a pan-senolytic or a pan-senotherapeutic, like there is no pan-oncotherapeutic. You need to understand the context. But these will all be part of the arsenal for true longevity medicine." "I don't see this as prevention of disease. The way I see therapies like ours, and the way the field of longevity is developing, is treating diseases decades before they develop. That's not a new concept — that's what we're doing in diabetes. You can be diagnosed with prediabetes today and reverse those biomarkers with lifestyle changes or metformin, and maybe never develop diabetes. That's exactly what we're doing here." "First of all, celebrating the first approved drugs from Rubedo — I don't think we're too far from that. But that's also a beginning, because you learn from the big momentum the GLP-1 agonists created: how a drug can start in one indication, create a new field, and prove that you can go beyond that. I hope in a few years we come back and talk about the next GLP-1 — this could be GPX4 modulators, or the senoadaptive drugs that are first in our pipeline." Links: Rubedo Life Sciences: https://www.rubedolife.comMarco Quarta's previous appearance on Translating Aging: Ep 35 — Targeting Pathologic Cells to Preserve Biological Youth
