Tozorakimab Cuts COPD Exacerbations by Up to 34% in Two Phase 3 Trials, FDA Sets Q1 2027 Decision
核心洞察
AstraZeneca's IL-33 (搜索) inhibitor tozorakimab reduced moderate-to-severe COPD (搜索) exacerbations by 29% in OBERON and 34% in TITANIA among former smokers versus placebo.
Across more than 2,300 randomized patients, exacerbation reductions reached roughly 30% and 29% in the overall trial populations including current smokers.
Benefit extended across blood eosinophil counts, including a 23% reduction below 150 cells/microliter, a subgroup where COPD (搜索) biologics have historically underperformed.
AstraZeneca's investigational interleukin-33 (IL-33 (搜索)) inhibitor tozorakimab significantly reduced moderate-to-severe exacerbations in chronic obstructive pulmonary disease (COPD (搜索)) across two replicate Phase 3 trials, data presented on September 8 at the European Respiratory Society (ERS) Congress in Barcelona and simultaneously published in the New England Journal of Medicine show.
The OBERON (NCT05166889) and TITANIA (NCT05158387) trials randomized just over 2,300 patients with symptomatic COPD (搜索) who had experienced at least two moderate or one severe exacerbation in the previous 12 months despite receiving maintenance inhaled therapy. Participants received either tozorakimab 300 mg or placebo every four weeks for 52 weeks, layered on top of existing inhaled standard-of-care treatment.
Exacerbation Reductions Across the Trial Populations
In the trials' primary population of former smokers, tozorakimab cut moderate-to-severe exacerbation rates by 29% in OBERON and 34% in TITANIA compared with placebo. In the overall trial populations, which included both current and former smokers, the drug reduced exacerbations by 30% and 29%, respectively.
The inclusion criteria were deliberately broad, enrolling current and former smokers across all blood eosinophil counts (BEC) and all stages of lung function severity. According to the trials' chief investigator, this marks the first time a COPD (搜索) biologic has demonstrated efficacy across the eosinophil spectrum, including below the 150 cells/µL threshold, regardless of smoking status.
Subgroup analysis by BEC showed a 23% reduction in patients below 150 cells/µL — a population where most COPD (搜索) biologics have historically underperformed — rising to 34% at 150 cells/µL or above and 43% at 300 cells/µL or above, in both current and former smoking patients across both trials. AstraZeneca states the results represent the first time a biologic has shown significant efficacy across such a broad COPD population in two replicate Phase 3 trials.
Safety and Tolerability
Overall safety was generally similar between the tozorakimab and placebo groups, although injection-site reactions occurred more frequently with tozorakimab. Severe adverse events leading to treatment discontinuation occurred in 3.1% of patients in OBERON and 3.7% in TITANIA. AstraZeneca reported no new safety signal across the 2,306 patients studied.
"Reducing exacerbations is one of the most important goals in the treatment of COPD (搜索) because flare-ups have a profound impact on patients' health, quality of life and long-term outcomes. It is encouraging to have an additional, safe therapy for patients who often struggle to breathe," said study leader Dr Frank Sciurba of the University of Pittsburgh.
Sharon Barr, Executive Vice President, BioPharmaceuticals R&D at AstraZeneca, said: "Today's groundbreaking tozorakimab results, from two replicate trials, set a new standard for COPD (搜索) treatment outcomes in a broad population of patients. AstraZeneca has clinically validated the novel approach of targeting the signalling of the two forms of IL-33 (搜索) to both decrease inflammation and disrupt the cycle of mucus dysfunction."
Regulatory Path and Competitive Landscape
The FDA has accepted tozorakimab's biologics licence application under Priority Review, with a PDUFA date expected in the first quarter of 2027. Regulatory review is also underway in the EU and China. The application seeks approval as an add-on maintenance treatment for adults with COPD (搜索).
If approved, tozorakimab would enter a COPD (搜索) biologics market currently dominated by Dupixent (dupilumab), which acts through the narrower IL-4 (搜索)/IL-13 (搜索) axis and is indicated for uncontrolled COPD patients with type-2 inflammation (BEC of 300 cells/µL or more). GSK's IL-5 (搜索)-targeting Nucala (mepolizumab) entered the space in 2025, approved by the FDA in Q2 2025 and by the EMA in Q1 2026, but like Dupixent is indicated only for moderate-to-severe COPD.
Among rival IL-33 (搜索) assets, Roche's astegolimab remains in Phase 3 (ARNASA; NCT05595642), while Sanofi's itepekimab failed to achieve its primary endpoint in the Phase 3 AERIFY-2 trial (NCT04751487), leaving tozorakimab, for now, as the only IL-33 asset with positive Phase 3 data across the eosinophil spectrum. Sanofi is advancing its bispecific nanobody lunsekimig, which targets thymic stromal lymphopoietin (TSLP (搜索)) and IL-13 (搜索), with a Phase IIb/III program (NCT07190209) in COPD (搜索) ongoing.
GlobalData's COPD (搜索) Market Drug Forecast expects the COPD market to grow to more than $30 billion across the seven major markets (US, France, Germany, Spain, Italy, UK and Japan) by 2034, with Dupixent, Nucala and tozorakimab positioned as leading players.
The results drew a positive response from some analysts, although AstraZeneca shares fell following the data release, declining approximately 1.3% to $158, suggesting investors are seeking commercial proof beyond strong clinical data. The ultimate clinical and commercial impact of tozorakimab will depend on how convincingly the Phase 3 results translate into regulatory approval, physician adoption and durable outcomes beyond the 52-week trial window.