Kymera Presents Phase 1 KT-621 Data in Japanese Adults, Notes Ongoing Phase 2b Trials

Kymera Therapeutics presented new Phase 1 data for its investigational oral STAT6 degrader KT-621 in healthy Japanese adults, showing results consistent with previous clinical studies. The company also highlighted that parallel Phase 2b trials for the drug in atopic dermatitis and asthma are ongoing, with data expected in 2027.

The Phase 1 trial in healthy Japanese adults, randomized, double-blind, and placebo-controlled, enrolled 24 participants across two dose levels randomized 3:1 to receive KT-621 or placebo once daily for seven days. KT-621 demonstrated rapid absorption, dose-proportional increases in plasma exposure, and rapid, sustained STAT6 degradation in blood, with median degradation of ≥98% at both dose levels at Day 7. The drug was well tolerated with a favorable safety profile, and results were comparable to those observed in non-Japanese adults and atopic dermatitis patients.

The ongoing Phase 2b trials include BROADEN2 in atopic dermatitis, enrolling approximately 200 patients aged 12 to 75 with moderate-to-severe disease over 16 weeks, with the primary endpoint being percent change in EASI from baseline. Data from BROADEN2 are expected by mid-2027. The BREADTH trial is enrolling 264 adults with moderate-to-severe eosinophilic asthma for 12 weeks, with the primary endpoint being pre-bronchodilator FEV1, and data are expected by late 2027.

The FDA has granted Fast Track designation for KT-621 in both atopic dermatitis and asthma. A Phase 1b atopic dermatitis readout showed deep STAT6 degradation in both blood and skin, measurable reductions in Type 2 inflammatory biomarkers, and clinical signal on EASI alongside patient-reported outcomes in comorbid asthma and allergic rhinitis. The chronic toxicology package in rat and non-human primate was completed with no adverse findings across all doses.

At a recent conference, Kymera's CEO emphasized the goal of delivering "biologics-like activity" in a once-daily oral drug, targeting more than 100 million Type 2 disease patients globally. The company estimates 40 million to 50 million of these patients have moderate-to-severe disease, representing the initial development population. Current annual sales of drugs in these spaces are around $20 billion to $25 billion, and the market could expand 5x to 10x across areas such as atopic dermatitis, asthma, chronic obstructive pulmonary disease, and eosinophilic esophagitis.

Kymera reported that KT-621's Phase Ib results were in the "dupilumab range" at day 28, with biomarker shifts corresponding to changes in clinical and patient-reported outcomes including itch, EASI, SCORAD, and sleeplessness. The company reported no treatment-related adverse events in the referenced study. With $1.55 billion in cash and runway into 2029, the company is also advancing another program, KT-579, an IRF5 degrader in Phase 1 healthy volunteers with data expected in the second half of 2026.