All three dose regimens of AbbVie's investigational anti-IL-13 monoclonal antibody zumilokibart beat placebo on the primary endpoint of EASI-75 at Week 16 in a Phase 2 study of adults with moderate to severe atopic dermatitis, the company announced September 30 from its North Chicago, Illinois headquarters.

The data, presented as a late-breaker at the 2026 Annual European Academy of Dermatology and Venereology (EADV) Congress in Vienna, come from APEX Part B, an ongoing randomized, double-blinded, placebo-controlled dose-finding study. Investigators randomized 346 participants to low-, mid-, or high-dose zumilokibart or placebo across a 16-week induction period. The primary endpoint measured the proportion of participants achieving at least 75% improvement from baseline in the Eczema Area and Severity Index (EASI-75) at Week 16.

Every zumilokibart regimen separated from placebo on that primary measure with statistical significance, according to AbbVie's press release.

The mid- and high-dose regimens also outperformed placebo across key secondary endpoints, including near-complete or complete skin clearance defined by EASI 90 and EASI 100 responses and itch improvement measured by the 4-point Numerical Rating Scale (I-NRS4). Notably, the mid-dose regimen produced greater percent reductions versus placebo in skin severity as early as Week 1 and in itch by Week 2 — an onset profile that will draw close attention from clinicians managing patients whose itch drives disease burden.

AbbVie has selected the mid-dose regimen for Phase 3 development, a decision that pairs the fastest observed onset in this dose-ranging study with the balance of efficacy and tolerability the company judged sufficient for pivotal-stage advancement.

Safety profile through Week 16

The safety database remains consistent with the drug class. Treatment-emergent adverse events occurring in at least 5% of any treatment group through Week 16 included nasopharyngitis, headache, noninfective conjunctivitis, upper respiratory tract infection, atopic dermatitis, and urinary tract infection. Conjunctivitis, in particular, is a familiar signal for clinicians who manage patients on IL-4 receptor alpha and IL-13 pathway inhibitors.

A long-acting IL-13 inhibitor enters a crowded field

Zumilokibart is a half-life extended monoclonal antibody targeting interleukin-13. Clinical data showed a human half-life of approximately 77 days — a pharmacokinetic property that could support extended dosing intervals if the drug reaches approval, though AbbVie has not yet detailed the Phase 3 dosing schedule.

The compound remains investigational. No regulatory authority has approved zumilokibart for any indication.

For dermatologists, the APEX Part B readout adds another IL-13-directed candidate to a moderate to severe atopic dermatitis pipeline already reshaped by biologics and oral small molecules over the past decade. The competitive question now shifts to Phase 3: whether the mid-dose regimen's early skin and itch improvements, combined with a roughly 77-day half-life, can translate into durable efficacy and a differentiated dosing proposition in head-to-head clinical practice.

Phase 3 development is the next milestone, and its design — including dosing interval and comparator choices — will clarify where zumilokibart might fit in the evolving atopic dermatitis treatment algorithm.