Zumilokibart could offer a less frequent biologic dosing option for adults with moderate-to-severe atopic dermatitis, with phase 3 trials planned for the second half of 2026.
On May 27, 2026, Apogee Therapeutics (Waltham, MA, USA) announced positive 16-week induction data from Part B of the phase 2 APEX trial evaluating zumilokibart (APG777), an investigational extended half-life monoclonal antibody targeting interleukin-13 (IL-13), in adults with moderate-to-severe atopic dermatitis (AD). The trial met its primary endpoint and key secondary endpoints with statistical significance, supporting advancement of the mid-dose regimen into phase 3 development.¹
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About the APEX trial
APEX is a two-part randomized, placebo-controlled phase 2 study evaluating the safety and efficacy of zumilokibart in patients with moderate-to-severe AD (NCT06395948)2. Part B was designed as an induction dose-optimization study and enrolled 346 adults, who were randomized 1:1:1:1 to receive high-, mid-, or low-dose zumilokibart, or placebo. The primary endpoint was the proportion of patients achieving at least a 75% improvement in Eczema Area and Severity Index score (EASI-75) at Week 16.¹
Key secondary endpoints included Validated Investigator Global Assessment (vIGA) 0/1, EASI-90, a reduction of at least 4 points in Itch Numeric Rating Scale score (I-NRS ≥4), EASI-100, and very low disease activity (vLDA), defined as EASI-90 plus I-NRS 0/1.¹
Key efficacy results
At Week 16, EASI-75 was achieved by 65.9% of patients receiving mid-dose zumilokibart compared with 23.4% of patients receiving placebo, representing a placebo-adjusted response rate of 41.9% (p<0.001). EASI-75 responses were also observed in 61.6% of patients in the high-dose group and 50.5% in the low-dose group, with all three zumilokibart dose groups demonstrating statistically significant improvements versus placebo (p<0.001).¹
Mid-dose zumilokibart also demonstrated significant improvements across key secondary endpoints at Week 16. IGA 0/1 was achieved by 46.0% of patients receiving mid-dose zumilokibart compared with 10.9% receiving placebo (p<0.001), while EASI-90 responses were reported in 47.4% and 9.3% of patients, respectively (p<0.001). A clinically meaningful improvement in itch, measured by I-NRS ≥4, was achieved by 50.5% of patients in the mid-dose group compared with 13.9% in the placebo group (p<0.001).¹
Complete skin clearance, measured by EASI-100, was achieved in 16.5% of patients receiving mid-dose zumilokibart compared with 3.4% receiving placebo (p<0.01). In addition, very low disease activity was achieved by 20.6% of patients receiving mid-dose zumilokibart compared with 4.5% in the placebo arm (p<0.01)
Safety findings
Zumilokibart was generally well tolerated, with a safety profile reported to be consistent with other agents in the class.¹ The most common treatment-emergent adverse events among patients receiving zumilokibart were nasopharyngitis, headache, and noninfective conjunctivitis.¹
Conjunctivitis rates appeared dose dependent, with a pooled conjunctivitis rate of 10.6% reported for the planned phase 3 mid-dose regimen, compared with 15.1% in the low-dose group and 20.7% in the high-dose group.¹
Commenting on the findings, Scott C. Schuster Distinguished Chair in Dermatology and Director, Atopic Dermatitis Program at Mass General Brigham and Professor of Dermatology, Harvard Medical School said “The Part B induction data demonstrated that zumilokibart delivered robust efficacy within the first 16 weeks with significantly fewer injections versus the current standard-of-care. Together with Part A data demonstrating that zumilokibart can be dosed every 3 to 6 months in maintenance with continuous and even enhanced efficacy, we are seeing a strong clinical profile that offers what dermatologists are looking for in clinical practice for our patients.”¹
Maintenance data and next steps
The Part B results build on previously reported Part A 52-week maintenance data, in which responses were maintained and, in some patients, deepened with every-3-month and every-6-month dosing. In Part A, EASI-75 responses were maintained by 75% and 85% of Week 16 responders receiving every-3-month and every-6-month dosing, respectively.3
Apogee plans to initiate three phase 3 studies of zumilokibart in moderate-to-severe AD in the second half of 2026, pending regulatory interactions. The ADventure 1 and ADventure 2 phase 3 program will evaluate zumilokibart as monotherapy, while ADventure TCS will assess the therapy in combination with background topical corticosteroids.¹
“Patients with atopic dermatitis and their physicians want therapies that provide durable and deeper disease control with less frequent dosing,” said Ruth Ann Vleugels, MD, MPH, MBA, Director of the Atopic Dermatitis Program at Mass General Brigham and Professor of Dermatology at Harvard Medical School.¹
References
- Apogee Therapeutics. Apogee Therapeutics announces positive 16-week Part B induction dose optimization results from phase 2 APEX trial of zumilokibart in moderate-to-severe atopic dermatitis [Press release]. May 27, 2026. Available at: www.biospace.com/press-releases/apogee-therapeutics-announces-positive-16-week-part-b-induction-dose-optimization-results-from-phase-2-apex-trial-of-zumilokibart-in-moderate-to-severe-atopic-dermatitis (accessed May 27, 2026).
- ClinicalTrials.gov. A study evaluating APG777 in atopic dermatitis. ClinicalTrials.gov identifier: NCT06395948.
- Apogee Therapeutics. 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 [Press release]. March 23, 2026. Available at: investors.apogeetherapeutics.com/news-releases/news-release-details/apogee-therapeutics-announces-positive-phase-2-part-52-week-data (accessed May 27, 2026).
Cite: Zumilokibart meets endpoints in phase 2 atopic dermatitis trial. touchDERMATOLOGY. May 28, 2026
Disclosure: This article was created by the touchDERMATOLOGY team utilizing AI as an editorial tool (ChatGPT [Large language model]. https://chat.openai.com/chat.) The content was developed and edited by human editors. No funding was received in the publication of this article.
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