The MIRANDA announcement follows AstraZeneca’s March report that the replicate phase 3 OBERON and TITANIA trials, which evaluated tozorakimab 300 mg every 4 weeks, also met their primary end points.3 Together, these studies form the core of the LUNA development program, with the ongoing PROSPERO extension focusing on severe exacerbations, including hospitalization and death, over 104 weeks.
Key Facts
Class: anti–IL-33 monoclonal antibody
Indication: COPD with exacerbation history
Design: DB, placebo-controlled
Dose: 300 mg every 2 weeks
Primary outcome: mod/severe exacerbations
Result: primary end point met
Safety: generally well tolerated
Status: investigational; filings planned
COPD remains a major source of morbidity and mortality globally and is the third leading cause of death worldwide excluding COVID-19, according to the World Health Organization.4 Current GOLD guidance emphasizes smoking cessation, vaccination, pulmonary rehabilitation, and inhaled bronchodilator-based therapy, with inhaled corticosteroids used selectively, often guided in part by eosinophil counts and exacerbation history.2 Despite these measures, many patients continue to exacerbate, and repeated events are associated with hospitalization, cardiovascular complications, accelerated disease progression, and death.
Tozorakimab targets IL-33, an upstream alarmin implicated in airway inflammation and epithelial dysfunction.5 Preclinical and translational work suggests the antibody may block signaling from both reduced and oxidized forms of IL-33, including pathways involving ST2 and RAGE/EGFR. In a phase 2a study in COPD, tozorakimab was previously investigated as a strategy to reduce exacerbations, but the precise place of IL-33 inhibition in COPD care remains unsettled pending phase 3 publication and regulatory review.6
Clinically, a positive program across former smokers, current smokers, and eosinophil strata would be notable because currently available biologic approaches in COPD have shown variable efficacy and often more selective target populations.2 Still, clinicians will likely want to see whether the effect size differs by smoking status, eosinophil count, concomitant inhaled triple therapy, and baseline exacerbation burden before judging where the drug might fit in practice.
Regulatory submissions are planned, according to the company.1 Key next steps are presentation of complete efficacy and safety data, peer-reviewed publication, and clarification of whether any eventual label would be limited to former smokers, a broader exacerbation-prone COPD population, or specific biomarker-defined groups.
References
Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease: 2026 Report. Accessed April 20, 2026. https://goldcopd.org/2026-gold-report-and-pocket-guide/
England E, Rees DG, Scott IC, et al. Tozorakimab (MEDI3506): an anti-IL-33 antibody that inhibits IL-33 signalling via ST2 and RAGE/EGFR to reduce inflammation and epithelial dysfunction. Sci Rep. 2023;13:9825.
Singh D, Guller P, Reid F, et al. A phase 2a trial of the IL-33 mAb tozorakimab in patients with COPD: FRONTIER-4. Eur Respir J. 2025. doi:10.1183/13993003.02231-2024