Stapokibart post-hoc analysis links eosinophil drop to EASI-75 gains in atopic dermatitis
A pooled analysis of phase II and phase III trials shows stapokibart lowered blood eosinophil counts and paired that drop with higher EASI-75 response, regardless of baseline eosinophil level.
Executive Summary
- Stapokibart treatment drove sustained drops in blood eosinophil counts over 16 weeks across two trials, and that biomarker change tracked with higher skin-clearance response rates than placebo.
- The effect held in patients with both high and low baseline eosinophil counts, suggesting the drug's benefit in atopic dermatitis is not confined to a biomarker-selected subgroup.
- Adverse events were similar between the two eosinophil subgroups and mostly mild or moderate, adding a tolerability data point to the same pooled population.
The finding
Eosinophils, a type of white blood cell, are involved in the inflammation that drives atopic dermatitis. A post-hoc analysis pooling stapokibart's phase II and phase III trials evaluated whether the drug's effect on blood eosinophil counts corresponded with its clinical efficacy. Blood eosinophil counts fell from baseline through week 16 in both trials: in the phase II AD002 trial, the high-dose arm dropped from 420 to 235 cells/µL and the low-dose arm from 530 to 315 cells/µL, while the phase III AD005 trial's stapokibart arm fell from 370 to 210 cells/µL. StapokibartStapokibart reduces blood eosinophil counts in patients with moderate-to-severe atopic dermatitis: a post-hoc analysis from phase II and phase III clinical trials.Jul 15, 2026
How it was done
AD002 randomly assigned 120 patients with moderate-to-severe atopic dermatitis to stapokibart 300 mg every two weeks (Q2W), 150 mg Q2W, or placebo for 16 weeks. AD005 randomly assigned 500 patients to stapokibart 300 mg Q2W or placebo for 16 weeks, followed by open-label stapokibart 300 mg Q2W through week 52. The analysis stratified efficacy and safety by baseline blood eosinophil count, splitting patients at a threshold of 500 cells/µL, and compared Eczema Area and Severity Index (a composite measure of rash extent and severity) 75% response, EASI-75, between stapokibart and placebo within each subgroup. StapokibartStapokibart reduces blood eosinophil counts in patients with moderate-to-severe atopic dermatitis: a post-hoc analysis from phase II and phase III clinical trials.Jul 15, 2026
The result
Stapokibart produced higher EASI-75 response rates than placebo at week 16 in both the high-eosinophil and low-eosinophil subgroups. Because the eosinophil split did not separate responders from non-responders, the analysis points to a treatment effect that does not depend on how inflamed a patient's blood eosinophil profile is at the start of treatment. StapokibartStapokibart reduces blood eosinophil counts in patients with moderate-to-severe atopic dermatitis: a post-hoc analysis from phase II and phase III clinical trials.Jul 15, 2026
Safety across subgroups
The incidence of adverse events was similar between the two baseline-eosinophil subgroups, and most events were mild or moderate. That consistency across a biomarker split, on top of the matched efficacy signal, reinforces that the pooled dataset found no difference in the drug's tolerability tied to baseline eosinophil level. StapokibartStapokibart reduces blood eosinophil counts in patients with moderate-to-severe atopic dermatitis: a post-hoc analysis from phase II and phase III clinical trials.Jul 15, 2026
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