SHERIDAN, WYOMING – July 25, 2025 – Roche has announced topline results from two pivotal clinical trials evaluating astegolimab for chronic obstructive pulmonary disease (COPD), highlighting a complex development path for the investigational monoclonal antibody. The phase IIb ALIENTO trial met its primary endpoint, while the phase III ARNASA trial did not, despite both showing numerical reductions in exacerbation rates.
Phase IIb ALIENTO Achieves Statistically Significant Reduction in Exacerbations
The ALIENTO study, which enrolled 1,301 patients, demonstrated a statistically significant 15.4% reduction in the annualised exacerbation rate (AER) over 52 weeks when astegolimab was administered every two weeks on top of standard COPD maintenance therapy. The patient population included both current and former smokers, regardless of blood eosinophil count, with a history of frequent exacerbations.
Phase III ARNASA Falls Short of Primary Endpoint
In contrast, the larger ARNASA study, which involved 1,375 participants, did not meet its primary endpoint. Although a 14.5% numerical reduction in AER was observed over the same period, the result did not achieve statistical significance. Both studies reported a lower-than-expected total number of exacerbations, potentially influencing outcome interpretations.
The safety profile for astegolimab remained consistent with previous data, and no new safety signals emerged during the trials.
"While COPD remains the third leading cause of death worldwide, patients and families have limited treatment options for managing this debilitating and complex disease," said Levi Garraway, MD, PhD, Roche’s Chief Medical Officer and Head of Global Product Development. "This was the first set of studies in an ‘all-comers’ COPD population, and we will discuss these data with regulatory authorities to evaluate next steps for astegolimab.”
Next Steps and Regulatory Engagement
Roche confirmed that it will engage regulatory bodies to determine a viable path forward for astegolimab. Detailed results from both studies will be presented at an upcoming medical meeting, offering a fuller clinical context for stakeholders and potential partners.
Study Design and Targeted Mechanism
Astegolimab is a fully human monoclonal antibody targeting the ST2 receptor, thereby inhibiting IL-33 signaling — a pathway implicated in airway inflammation. Both ALIENTO and ARNASA were multicenter, double-blind, placebo-controlled studies conducted in patients receiving one of three standard maintenance therapies:
- ICS + LABA
- LAMA + LABA
- ICS + LAMA + LABA
Participants received astegolimab either every two or four weeks, and the primary endpoint focused on moderate and severe exacerbations over a 52-week period. These exacerbations are characterized by acute worsening of respiratory symptoms requiring treatment intensification.
Strategic Outlook and Industry Relevance
Although the ARNASA outcome tempers near-term momentum, the statistically significant results in ALIENTO reinforce astegolimab’s potential as a novel treatment for a broad COPD population — a therapeutic area still in need of innovation. The trials mark the first time a biologic therapy has been tested across an “all-comers” COPD cohort, setting a precedent for future clinical programs.
About Roche
Headquartered in Basel, Roche is the world’s largest biotech company and a global leader in in-vitro diagnostics. The company integrates its strengths in diagnostics and pharmaceuticals with clinical data to advance personalized healthcare. Sustainability is a core element of its strategy, with Roche committing to net zero emissions by 2045 through the Science Based Targets initiative and the Sustainable Markets Initiative.
Genentech (U.S.) is a wholly owned member of the Roche Group, and Roche is also the majority stakeholder in Japan’s Chugai Pharmaceutical.
Learn more at www.roche.com