Tozorakimab's LUNA papers detail AstraZeneca's four-trial Phase 3 COPD program
A published protocol paper lays out how AstraZeneca structured OBERON, TITANIA, MIRANDA and PROSPERO, the largest pivotal biologic program in COPD to test an anti-IL-33 antibody against exacerbations.
Executive Summary
- A peer-reviewed paper lays out the design of AstraZeneca's four-trial Phase 3 LUNA program testing an anti-IL-33 antibody in COPD patients with a history of exacerbations, rather than reporting new trial results.
- All four trials share a common primary endpoint structure built around the annualized rate of moderate-to-severe exacerbations, assessed first in former smokers and then in the broader smoking population.
- IL-33 blockade in COPD is not a solitary approach: three sponsors have advanced antibodies against the same target into Phase 3 in this indication, making the LUNA program's design, and the antibody's dual neutralization of both forms of IL-33, the differentiating feature to watch rather than the mechanism itself.
- Because the design paper standardizes how exacerbation reduction will be measured and compared across the program's trials, it sets the framework against which the individual OBERON, TITANIA and MIRANDA results should be read once fully reported.
The publication
The paper, dated July 20, 2026, describes the design of OBERON (NCT05166889), TITANIA (NCT05158387), MIRANDA (NCT06040086) and PROSPERO (NCT05742802), four randomized, double-blind, placebo-controlled Phase 3 studies of tozorakimab in symptomatic COPD with a history of exacerbations. The authors describe the program as the largest pivotal biologic trial program conducted in COPD to date. OBERON itself randomized 1,132 participants and completed on March 11, 2026, after a primary completion date that had moved from June 2025 to January 19, 2026 over the trial's five-year run. Phase+1Phase III LUNA clinical programme: design of four randomised, double-blind, placebo-controlled studies assessing the efficacy and safety of tozorakimab in patients with symptomatic COPD and a high risk of exacerbations.Jul 20, 2026Efficacy and Safety of Tozorakimab in Symptomatic Chronic Obstructive Pulmonary Disease With a History of ExacerbationsNCT05166889
Probability of SuccessBased on the AppliedXL Probability of Success model. For more information about the methodology, read the research here.
How it was done
In OBERON and TITANIA, 1,132 and 1,172 participants respectively were randomized to tozorakimab 300 mg every four or eight weeks or placebo for 52 weeks. MIRANDA randomized 1,454 participants 3:2 to tozorakimab 300 mg every two weeks or placebo for at least 52 weeks. PROSPERO extends treatment in OBERON and TITANIA completers for an additional 28 or 52 weeks, and re-randomizes prior placebo patients 1:1 to drug or placebo. The shared primary endpoint across OBERON, TITANIA and MIRANDA is the annualized rate of moderate-to-severe COPD exacerbations, assessed first in former smokers and then in the combined current- and former-smoker population; PROSPERO's primary endpoint is the annualized rate of severe exacerbations. Secondary measures span lung function (FEV1), symptom burden (E-RS:COPD, CAT, SGRQ) and safety, including anti-drug antibody incidence, over 52 to 60 weeks. PhasePhase III LUNA clinical programme: design of four randomised, double-blind, placebo-controlled studies assessing the efficacy and safety of tozorakimab in patients with symptomatic COPD and a high risk of exacerbations.Jul 20, 2026
What the target has to answer for
IL-33 is targeted by three direct Phase 3 comparators in COPD beyond tozorakimab's own long-term safety extension: Sanofi's itepekimab and Roche's astegolimab are both being tested against placebo in symptomatic COPD populations. None of the three programs has a completed Phase 3 in this pair that failed: of the trials counted for IL-33 in COPD at Phase 3, all completed events on record ended without termination. That gives the mechanism a track record without a defeat, but it also means no program has yet cleared the bar of a fully reported, statistically characterized exacerbation-rate reduction in this population; the LUNA design paper sets the terms for that comparison rather than resolving it.
Reach of the program
Tozorakimab's COPD footprint extends beyond LUNA's four registrational trials into a fifth, ongoing long-term safety study (NCT07566195) and two earlier Phase 1 and Phase 2 trials that established the drug's tolerability profile before the pivotal program began. Across its full COPD and adjacent-indication portfolio, AstraZeneca is running eight tozorakimab trials, none of them terminated.
This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.