Design: Prespecified pooled analysis of two phase 3 RCTs
Population: 2682 current or former smokers with COPD and frequent exacerbations
Primary outcome: Annualised moderate or severe exacerbation rate
Effect: Q2W rate ratio 0.85 (0.76–0.96); Q4W 0.88 (0.78–0.99)

ALIENTO and ARNASA were double-blind, placebo-controlled trials of astegolimab, an anti-ST2 monoclonal antibody, in current or former smokers with COPD and frequent exacerbations, regardless of eosinophil count. This prespecified pooled analysis of 2682 participants was published in the American Journal of Respiratory and Critical Care Medicine in September.

Over 52 weeks, moderate or severe exacerbations fell by 15% with dosing every two weeks (rate ratio 0.85, 95% CI 0.76 to 0.96) and 12% with dosing every four weeks (0.88, 0.78 to 0.99). Severe exacerbations were 32% lower with two-weekly dosing (0.68, 0.52 to 0.87), a nominal result. It was well tolerated.

The appeal is a biologic that does not depend on eosinophils. The effect is modest, smaller than seen with type 2 biologics in eosinophilic COPD.

Optimise inhaled triple therapy, pulmonary rehabilitation and smoking cessation first.
Consider eosinophil-guided biologics where eligible.
Check regulatory status before discussing astegolimab with patients.

Why it matters

It may open biologic therapy to COPD patients without eosinophilic inflammation.

The statistics, in plain English

A rate ratio of 0.85 means 15% fewer exacerbations, and the interval stays below 1. The severe-exacerbation result is labelled nominal because it sits lower in the testing hierarchy, so it is supportive rather than confirmed. Pooling two trials also increases precision relative to either alone.