All three dose regimens of zumilokibart met the primary endpoint in the Phase 2 APEX Part B study, delivering significantly greater Eczema Area and Severity Index-75 (EASI-75) response rates than placebo at Week 16 in adults with moderate-to-severe atopic dermatitis. AbbVie, the drug's developer, has selected the mid-dose regimen for Phase 3 development.

The data come from primary results of the ongoing study, presented at the 2026 Annual European Academy of Dermatology and Venereology (EADV) Congress in Vienna, Austria. Zumilokibart is a half-life-extended monoclonal antibody targeting interleukin (IL)-13, and the dosing frequency it may permit could become a differentiator in a crowded AD pipeline.

"Atopic dermatitis is a chronic disease, and the frequency of administration can be an important consideration when selecting a long-term therapy," says Melinda Gooderham, MD, FRCPC, of the SKiN Centre for Dermatology and Queen's University in Ontario, Canada, in a news release. "At Week 16, zumilokibart demonstrated improvements in skin clearance and itch. These findings support the further evaluation of zumilokibart as a long-term treatment for atopic dermatitis."

Trial Design

APEX Part B is an ongoing randomized, double-blind, placebo-controlled Phase 2 dose-finding study. Investigators randomized 346 adults with moderate-to-severe AD in a 1:1:1:1 ratio to one of three zumilokibart dose regimens — low, mid, or high — or placebo during a 16-week induction period. The primary endpoint was the proportion of participants achieving at least a 75% improvement from baseline in EASI at Week 16.

One design detail matters for interpreting the Phase 3 plan: the mid-dose regimen was identical to the induction regimen evaluated in APEX Part A, giving AbbVie consistency across the program as the molecule moves into confirmatory trials.

Efficacy Findings

The EASI-75 result held across all three dose regimens at Week 16. All doses also produced statistically significant improvements in itch on the Itch Numeric Rating Scale 4 (I-NRS4).

The mid- and high-dose regimens went further, showing significantly greater improvement than placebo across key secondary endpoints. These included near-complete or complete skin clearance based on EASI 90 and EASI 100, and itch improvement on I-NRS4.

Onset signals also favored the mid-dose regimen. It achieved greater percent reductions versus placebo in skin severity, measured by EASI, as early as Week 1, and in itch, measured by I-NRS, by Week 2. For patients whose itch drives treatment dissatisfaction, that early separation from placebo is a clinically relevant marker, though the released results do not specify the absolute response rates behind the comparisons.

Safety

Through Week 16, the most common treatment-emergent adverse events were nasopharyngitis, headache, noninfective conjunctivitis, upper respiratory tract infection, atopic dermatitis, and urinary tract infection. The profile is consistent with the conjunctivitis signal familiar from other agents in the IL-13 and IL-4/IL-13 classes, and the released data do not report discontinuations attributable to adverse events.

What Comes Next

The mid-dose selection sets up Phase 3 evaluation of zumilokibart as a long-term maintenance therapy for moderate-to-severe AD, with the half-life extension design positioned to reduce injection burden. Pending confirmatory trials, dermatologists will be watching whether the Week 16 efficacy and early-onset signals translate into durable responses and a convenient administration schedule.