Positive 16-Week Findings Identified for APG777 in Patients with Atopic Dermatitis

The investigational anti-interleukin (IL)-13 monoclonal antibody APG777 and its use among adults with moderate-to-severe atopic dermatitis has led to positive results, according to the phase 2 APEX Part A trial.1

In this announcement by Apogee Therapeutics, Inc., APG777 was specifically noted as having met all of its primary and key secondary endpoints, including the observed 71.0% decrease from baseline in Eczema Area Severity Index (EASI) at 16 weeks. The drug also led to EASI-75 scores in 66.9% of trial subjects (42.5% placebo-adjusted) at the same point, described in the announcement as the highest topline and placebo-adjusted efficacy of any biologic drug observed in a global analysis.

“The Phase 2 Part A results are exciting, with APG777 demonstrating promising efficacy results from only four injection days over the initial 16-week induction period,” Emma Guttman-Yassky, MD, PhD, Waldman Professor of Dermatology and Immunology and Health System Chair of the Kimberly and Eric J. Waldman Department of Dermatology at the Icahn School of Medicine at Mount Sinai, said in a statement.1 “Despite meaningful advances in atopic dermatitis treatment, there remains a significant unmet need to reduce the injection burden for patients while continuing to improve patient outcomes.”

Atopic dermatitis is a chronic skin disease that has seen a number of new therapeutic options come into existence in recent years. APG777, an investigational anti-IL-13 monoclonal antibody was assessed in this randomized, placebo-controlled study among 123 individuals. Each trial subject was assigned in a 2:1 ratio to be given either APG777 or a placebo.

Induction dosing of 720 mg at the 0 and 2-week marks was used in the induction phase, followed by maintenance dosing of 360 mg at the 4 and 12-week marks. Those taking part in the analysis who responded to APG777 continued into a maintenance phase that investigators designed to assess dosing intervals of every 3 or 6 months.

The APEX Part A trial met its primary endpoint, with a statistically significant improvement in EASI scores being observed by the investigative team.1 They highlighted that the least squares mean percentage reduction in EASI from baseline was shown to be 71.0% in the APG777 cohort, compared to 33.8% in the placebo cohort (P < .001).

In terms of 75% EASI improvement from baseline (EASI-75), 66.9% of those being assessed in the APG777 arm attained this milestone, versus only 24.6% of those on placebo (P < .001). A pre-specified sensitivity analysis confirmed the consistency of such findings in both moderate and severe disease subgroups.

Additionally, the researchers identified an exposure-response relationship, highlighting that trial subjects in the third and fourth quartiles for drug exposure attained EASI-75 rates of 83.3% and 89.5%, respectively. In terms of secondary endpoints, findings also aligned with or exceeded current standards of care.

Proportions of individuals achieving a Validated Investigator Global Assessment (vIGA) score of 0 or 1—indicating clear or almost clear skin—was found by the APEX team to be 34.9% in the APG777 group compared to only 17.3% in the placebo group (P < .05). Likewise, the team concluded that 33.9% of patients in the treatment arm had achieved EASI-90, compared to only 14.7% among those given a placebo (P < .05).

Among those in the subgroup with the highest exposure levels, it was noted that 63.2% attained both vIGA 0/1 and EASI-90 thresholds by the 16-week mark. Additionally, the investigators found that APG777 also produced a rapid and statistically significant reduction in pruritus, with a 50.7% Itch Numeric Rating Scale (NRS) score decrease by the 1-week mark. This was compared to a 23.2% reduction observed among those in the placebo arm (P < .01).

The treatment was well tolerated in the study's safety analysis. The serious treatment-emergent adverse event (TEAE) rate was noted as low, at 1.2% among APG777-treated patients. This was compared to a TEAE rate of 2.4% in those given a placebo.

The most commonly reported TEAEs, each occurring in 5% or more of participants in either cohort, included upper respiratory tract infection, non-infective conjunctivitis, and nasopharyngitis, with the latter 2 taking place less frequently in the APG777 arm. Adverse event-related drug discontinuation was shown to be infrequent (2.4%) as well. There were also no injection site reactions reported in those given APG777.

Part B of the APEX trial remains ongoing, with investigators assessing higher dosing levels of APG777. The Apogee announcement notes that those being evaluated are expected to attain exposure levels similar to the top quartile from Part A, with this portion of the trial's data being anticipated by mid-2026.1

Additionally, the investigative team noted that the results of the maintenance phase of Part A, evaluating extended dosing intervals of 3 or 6 months, are slated to be released within the first half of 2026.

“I look forward to seeing the first half-life extended antibody in AD progress and I am excited about Apogee’s studies that are bringing this therapy closer to patients,” Guttman-Yasky said in a statement.1

References

1. Apogee Therapeutics Announces Positive 16-Week Data from Phase 2 APEX Clinical Trial of APG777, its Potentially Best-in-Class Anti-IL-13 Antibody, in Moderate-to-Severe Atopic Dermatitis. Apogee Therapeutics, Inc. July 7, 2025. https://www.globenewswire.com/news-release/2025/07/07/3110862/0/en/Apogee-Therapeutics-Announces-Positive-16-Week-Data-from-Phase-2-APEX-Clinical-Trial-of-APG777-its-Potentially-Best-in-Class-Anti-IL-13-Antibody-in-Moderate-to-Severe-Atopic-Dermat.html.