New data released this week by Apogee Therapeutics has raised optimism among patients and clinicians dealing with moderate-to-severe atopic dermatitis (AD). In the Phase 2 APEX Part A trial, the anti-IL-13 antibody APG777 achieved impressive efficacy, including what may be the best topline response rates yet reported in a biologic study for AD.

Trial Design and Efficacy Results

The APEX Part A trial enrolled 123 adults with moderate-to-severe AD, randomized in a 2:1 ratio to receive APG777 or placebo. The induction regimen included higher doses at the start (720 mg at Weeks 0 and 2) followed by 360 mg at Weeks 4 and 12. Outcomes were measured at Week 16.

The drug met its primary endpoint, with patients receiving APG777 experiencing a 71.0% reduction in their Eczema Area and Severity Index (EASI) score, compared with a 33.8% reduction in the placebo group. The difference was statistically significant and demonstrated a robust treatment effect.

Secondary endpoints supported the primary outcome. EASI-75, which reflects at least a 75% improvement in EASI, was achieved by 66.9% of treated patients compared with 24.6% on placebo. EASI-90 was reached by 33.9% of patients on APG777, versus 14.7% on placebo. A measure of overall skin clearance, the validated Investigator Global Assessment (vIGA) score of 0 or 1, was achieved by 34.9% of patients on treatment compared with 17.3% on placebo.

Symptom relief was also evident very early. By Week 1, patients on APG777 reported more than a 50% decrease in itch severity, while the placebo group saw a 23% reduction. Notably, higher levels of drug exposure were linked with stronger outcomes. In patients in the top two exposure quartiles, EASI-75 response rates rose above 80%, highlighting the potential benefit of optimized dosing.

Safety and Next Steps

The safety profile of APG777 was encouraging. Most treatment-emergent side effects were mild to moderate, and serious adverse events were rare. Only a small percentage of patients discontinued treatment due to adverse events. Importantly, there were no injection site reactions in the APG777 arm, a notable finding given that such reactions are often seen with injectable biologics.

A unique aspect of this trial is the evaluation of extended dosing schedules. After the induction period, patients in Part A are being followed to test whether maintenance dosing every three or six months can sustain the benefits. If effective, this would represent a significant convenience advantage for patients, reducing the treatment burden associated with more frequent injections. Data from this maintenance phase are expected in 2026.

Meanwhile, Part B of the APEX trial is ongoing. It is exploring higher doses of APG777 to replicate the strong results observed in the patients with the highest drug exposure in Part A. Results from Part B are expected by mid-2026. Apogee also plans to move into Phase 3 development later in 2026, should the results remain favourable. The company is additionally advancing APG279, a next-generation molecule designed to combine IL-13 inhibition with OX40L blockade, and expects to test it against Dupixent in a head-to-head study beginning in late 2026.

These findings position APG777 as one of the most promising new therapies for moderate-to-severe atopic dermatitis. If the benefits are maintained over time with a good safety profile and less frequent dosing, the drug could become a strong competitor in a field currently dominated by Dupixent. Patients and physicians alike will be awaiting longer-term outcomes to confirm durability, real-world applicability, and comparative effectiveness.