Verekitug, a Novel Antibody Antagonist to the TSLP Receptor in Adults with Asthma: A 32-Week Randomized Phase 1b Multiple Ascending-Dose Trial

Verekitug, a novel, high-affinity, fully human monoclonal antibody targeting thymic stromal lymphopoietin receptor (TSLPR), is in development as a potential treatment for severe asthma, chronic rhinosinusitis with nasal polyps (CRSwNP), and chronic obstructive pulmonary disease (COPD). This phase 1b, double-blind, randomized, placebo-controlled, multiple ascending-dose trial assessed the safety, tolerability, immunogenicity, pharmacokinetics, and pharmacodynamics of verekitug administered subcutaneously in patients with mild-moderate asthma. Thirty-two participants were randomized in 4 placebo-controlled dosing cohorts (3 × 100-mg or 200-mg doses, once every 4 weeks; 2 × 300-mg doses, once every 12 weeks; single 25-mg dose) and observed for 32 weeks. The primary endpoint was safety; secondary endpoints were pharmacokinetics and immunogenicity. Exploratory endpoints included TSLPR occupancy and biomarker effects. Treatment-emergent adverse events were mild or moderate. Complete TSLPR occupancy was observed at the first timepoint (2 weeks post dose) and maintained for 24 weeks (doses ≥100 mg). Rapid mean reductions in fractional exhaled nitric oxide, eosinophils, and interleukin-5 (up to -54%, -65%, and -64%, respectively) were sustained up to 24 weeks (doses ≥100 mg). The mean verekitug half-life was ~20 days. Low-titer antidrug antibody response was observed in some participants, without clinically meaningful impact on pharmacokinetics, pharmacodynamics, or safety. Verekitug was generally well tolerated, with rapid, substantial, and sustained effects on asthma biomarkers. These findings support further development of verekitug for treating severe asthma, CRSwNP, and COPD.