APEX: Zumilokibart Shows Durable Response at 52 Weeks in Atopic Dermatitis

New positive 52-week maintenance findings have been released from Part A of the phase 2 APEX clinical study on zumilokibart (APG777) in adults with moderate-to-severe atopic dermatitis.1

This March 23 announcement by Apogee Therapeutics, Inc., highlight key phase 2 findings on zumilokibart, supporting a potentially differentiated dosing profile compared with existing therapies for atopic dermatitis. This investigational anti-interleukin (IL)-13 monoclonal antibody was evaluated in the APEX study among individuals living with this chronic skin condition associated with significant itch, sleep disruption, and quality of life issues.

“Because atopic dermatitis is a chronic disease, maintaining disease control over time is critically important,” 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 in New York City, said in a statement.1

APEX Design and Findings

Zumilokibart was designed as a subcutaneous, extended half-life monoclonal antibody for selectively targeting the IL-13 cytokine, known to be central to the inflammatory cascade underlying atopic dermatitis. The 52-week maintenance phase of the APEX study involved an assessment of a 360-mg dose of zumilokibart on 3- and 6-month administration schedules. Analyses focused on 2 populations: individuals attaining a clinical response at the 16-week mark and the broader cohort of all zumilokibart-treated subjects across the full 52-week study period.

Among those responding at Week 16, 75% and 85% of patients on every-3-month and every-6-month dosing, respectively, were shown to have maintained an Eczema Area and Severity Index (EASI) reduction of at least 75% (EASI-75) at Week 52. Validated Investigator's Global Assessment (vIGA) scores of 0 or 1, suggesting clear or almost-clear skin, were found to have been sustained in 86% of subjects on the 3-month regimen and 78% on the 6-month regimen within the same responder population.

Across the full treated population, investigators observed deepening of efficacy at both dosing intervals for all lesional and itch measures through the end of the study period. Zumilokibart was shown to be generally well tolerated over the 52-week course of the analysis, with the team finding its safety profile largely consistent with other agents targeting the IL-13 pathway. The most frequently reported treatment-emergent adverse events (TEAEs) were noted as noninfective conjunctivitis, upper respiratory tract infection, and nasopharyngitis.

Next Steps for Zumilokibart

APEX Part B, a placebo-controlled dose-optimization cohort, has involved 347 individuals randomized equally across high-, medium-, and low-dose zumilokibart and placebo arms. Sixteen-week induction data drawn from Part B are anticipated by the company in the second quarter of 2026.

“These 52-week findings for the full population are particularly encouraging for patients who did not fully respond during the first 16 weeks of treatment, suggesting that responses to zumilokibart may continue to deepen over time,” Guttman-Yassky said in her statement.1 “I look forward to seeing how these results translate in the upcoming Part B data and Phase 3 trial starting later this year.”

Pending such findings and regulatory feedback, Apogee Therapeutics’ release indicated the company’s plans to initiate phase 3 research in the second half of 2026, with a potential commercial launch targeted for 2029. These current results are slated to be featured in a late-breaking oral presentation at the 2026 American Academy of Dermatology (AAD) Annual Meeting on March 28, 2026, at 10:00 AM.

References

1. Apogee Therapeutics Announces Positive Phase 2 Part A 52-Week Data of Zumilokibart (APG777), Demonstrating Maintenance and Deepening of Responses with Every 3- and 6-Month Dosing in Moderate-to-Severe Atopic Dermatitis. Apogee Therapeutics. March 23, 2026. https://investors.apogeetherapeutics.com/news-releases/news-release-details/apogee-therapeutics-announces-positive-phase-2-part-52-week-data.

2. Smith T. Positive 16-Week Findings Identified for APG777 in Patients with Atopic Dermatitis. HCPLive. July 7, 2025. Accessed March 23, 2026. https://www.hcplive.com/view/positive-16-week-findings-identified-apg777-patients-atopic-dermatitis.