Kymera's Oral Eczema Drug Enters Key Trial, Targeting Dupixent's Reign

WATERTOWN, MA – November 25, 2025 – In the high-stakes race to dominate the booming atopic dermatitis market, Kymera Therapeutics has just fired a starting pistol. The clinical-stage biotech announced today it has dosed the first patient in its BROADEN2 Phase 2b clinical trial, a critical study evaluating its novel, once-daily oral drug, KT-621. This milestone moves the company one step closer to potentially disrupting a field currently led by injectable blockbusters and challenged by oral alternatives with significant safety concerns.

For investors and industry leaders, the trial's initiation is more than a procedural update; it's a major move in a strategic chess match. At stake is a share of a market valued at over $16 billion and projected to swell significantly by the decade's end. Kymera is betting that its first-in-class STAT6 degrader can offer the efficacy of a biologic in the convenience of a pill, a combination that has so far proven elusive and represents a massive unmet need for millions of patients.

The Battleground: A Market of Needles and Warnings

The atopic dermatitis (AD) landscape is dominated by a clear titan: Dupixent. Co-marketed by Sanofi and Regeneron, this injectable biologic has transformed treatment for moderate-to-severe disease, generating over $14 billion in sales in 2024 by effectively blocking the IL-4 and IL-13 inflammatory pathways. Its success set a high bar for efficacy and validated this specific biological pathway as the key to controlling the disease. However, its success comes with the burden of the needle—a significant barrier for patients due to inconvenience, injection-site pain, and needle phobia.

This created an opening for oral alternatives. Companies like AbbVie and Pfizer have capitalized on this with their potent JAK inhibitors, Rinvoq and Cibinqo, respectively. These pills offer the convenience patients crave and have demonstrated impressive efficacy, in some cases with a faster onset of action than injectables. Yet, they come with a major caveat: a class-wide FDA “black box” warning for risks of serious infections, major cardiovascular events, and other side effects. This forces a difficult trade-off for patients and physicians, limiting the use of these powerful oral drugs.

Kymera's KT-621 is being developed to navigate this precise gap. The goal is to deliver the targeted mechanism of the market-leading biologic, Dupixent, but in a simple, once-daily pill, and without the safety liabilities of the JAK inhibitor class. Success in the BROADEN2 trial could position KT-621 as a best-of-both-worlds therapy and a formidable future competitor.

Hacking Inflammation from the Inside Out

What sets KT-621 apart is its cutting-edge science. It isn't a traditional inhibitor; it's a targeted protein degrader. While most drugs work by binding to a protein to block its function—like putting a key in a lock—Kymera's drug works by flagging the target protein for complete destruction by the cell's own disposal machinery. Instead of just silencing the signal, it eliminates the switch entirely.

The target in this case is STAT6, a transcription factor that acts as the central intracellular hub for the same IL-4/IL-13 pathway that Dupixent blocks from the outside. By eliminating STAT6, Kymera aims to achieve a “Dupixent-in-a-pill” effect. This approach is not only novel but also catalytic, meaning a single drug molecule can trigger the destruction of multiple STAT6 proteins, potentially leading to a potent and durable effect at lower doses.

This technology also allows drug developers to go after targets previously considered “undruggable” by conventional small molecules, like STAT6. “The initiation of dosing in the BROADEN2 trial represents a major step in the advancement of our first-in-industry STAT6 degrader program,” said Jared Gollob, MD, Chief Medical Officer at Kymera, in the company's announcement. He emphasized the goal of realizing KT-621's promise as a “first-in-class oral treatment option for millions of patients.”

The Clinical Gauntlet: A Deliberate Path to Proof

Before reaching this pivotal Phase 2b stage, KT-621 built a strong foundation of data. In a Phase 1 study with 118 healthy volunteers, the drug was well-tolerated with a safety profile described as “undifferentiated from placebo.” Crucially, it demonstrated potent STAT6 degradation—over 95% in both blood and skin at higher doses—and reduced key inflammatory biomarkers associated with AD.

Now, the BROADEN2 trial will put this promise to the test in the real world. The randomized, double-blind, placebo-controlled study will enroll approximately 200 patients with moderate-to-severe AD. Over 16 weeks, it will evaluate three different doses of KT-621, with the primary goal of measuring the percentage change in the Eczema Area and Severity Index (EASI) score, a standard metric for disease severity. Topline results from this crucial study are expected by mid-2027.

However, investors won't have to wait that long for the next major catalyst. Kymera confirmed that data from its smaller, open-label Phase 1b trial in AD patients is due to be reported in December 2025. This will provide the first glimpse of KT-621’s clinical activity in its target population, setting the stage for the larger Phase 2b readout. Further underscoring the platform's potential, Kymera is also on track to initiate a parallel Phase 2b trial in asthma in the first quarter of 2026, aiming to accelerate development across multiple Type 2 inflammatory diseases.

A Future Free from Trade-Offs?

For the millions living with atopic dermatitis, the disease is far more than a skin condition. It is a chronic, relentless cycle of intense itch, painful skin, and sleepless nights that carries a heavy psychosocial burden, including high rates of anxiety and depression. Current treatment options force an undesirable choice: the inconvenience and discomfort of injections or the significant safety concerns of existing oral therapies.

An effective oral agent with a clean safety profile remains the holy grail in AD treatment. It would not only reduce the treatment burden but could also broaden access for patients hesitant to start injectable therapy. Kymera believes KT-621 can be that therapy. The journey from prototype to profit is long and fraught with risk, but with the BROADEN2 trial now underway, the company has taken a decisive step forward. The upcoming data readouts in December 2025 and mid-2027 will be critical inflection points, determining whether this innovative approach to hacking inflammation can truly change the paradigm for treating atopic dermatitis and a host of other allergic diseases.