- Design
- two replicate phase 3, randomised, placebo-controlled trials over 52 weeks (OBERON and TITANIA)
- Population
- about 1,750 adults with COPD, current or former smokers, with an exacerbation in the previous year despite stable inhaled maintenance therapy; no eosinophil eligibility criteria
- Primary outcome
- annualised rate of moderate or severe exacerbations over 52 weeks among former smokers
- Effect
- former smokers 1.34 vs 1.90 (rate ratio 0.71, 95% CI 0.57-0.88) in OBERON and 1.37 vs 2.07 (0.66, 0.55-0.80) in TITANIA; overall population rate ratios 0.70 and 0.71
Biologics for COPD have so far belonged to the eosinophilic phenotype, which leaves most patients with frequent exacerbations without an option beyond inhalers. Tozorakimab blocks interleukin-33, a pathway upstream of both eosinophilic and neutrophilic inflammation, and its two replicate phase 3 trials deliberately set no eosinophil entry criterion.
OBERON and TITANIA enrolled adults who were current or former smokers with COPD and at least one exacerbation in the previous year despite stable standard-of-care inhaled maintenance therapy, and randomised them to subcutaneous tozorakimab 300 mg or placebo every four weeks for 52 weeks. OBERON included 446 and 431 patients in the two groups, TITANIA 438 and 435. The primary endpoint was the annualised rate of moderate or severe exacerbations among former smokers.
Both trials met it. Among former smokers, annualised exacerbations fell from 1.90 to 1.34 in OBERON (rate ratio 0.71, 95% CI 0.57 to 0.88) and from 2.07 to 1.37 in TITANIA (rate ratio 0.66, 95% CI 0.55 to 0.80). In the overall population the reduction was consistent: 2.00 to 1.41 (rate ratio 0.70, 95% CI 0.58 to 0.85) and 2.03 to 1.44 (rate ratio 0.71, 95% CI 0.59 to 0.84). Adverse events occurred in 70.4% against 77.2% in OBERON and 80.1% against 79.8% in TITANIA.
Two replicate trials agreeing this closely is the most persuasive part of the result. What it does not settle is who should receive it: an eosinophil-agnostic trial shows the drug works across the enrolled population, not that eosinophil count is irrelevant to selecting patients, and the trials ran 52 weeks in people who were already exacerbating. Cost and availability will decide the rest, and neither is addressed here.
- Confirm inhaled maintenance therapy is optimised and actually being taken before considering any add-on biologic
- Record exacerbation frequency over the past year explicitly; it is the entry criterion that defines who these results apply to
- Do not use a low eosinophil count to rule a patient out of this class on current evidence
- Note that adverse event rates were no higher than placebo across both trials
- Treat cost and availability as the practical determinant; this evidence does not establish access anywhere
The statistics, in plain English
A rate ratio of 0.70 means about 30% fewer exacerbations per patient-year, which on these baseline rates translates to roughly 0.6 fewer events a year, or one avoided exacerbation for every two patients treated for a year. The confidence intervals in both trials sit clearly below 1.0 and, more importantly, the two trials produced nearly identical estimates, which is far stronger evidence than one trial with a narrow interval. Because entry required a recent exacerbation, these rates come from a population already at high risk; the same relative reduction applied to someone exacerbating once every few years would avoid far less.
Read the rest in the app
You have read your two free briefings this month. The app carries all 27 specialties, every morning, free — and this finding is waiting in it.
Scan to keep reading on your phone. No account needed to start.
Tomorrow morning, before your first patient
One edition a day for top clinical updates, written by the desk, every claim tied to its paper. Six minutes.
Get the app — free