Stapokibart for Severe Uncontrolled Chronic Rhinosinusitis With Nasal Polyps

Importance Chronic rhinosinusitis with nasal polyps causes severe symptoms and impaired quality of life. Stapokibart is a novel monoclonal antibody that targets interleukin 4Rα. Objective To assess the efficacy and safety of stapokibart as an add-on treatment to intranasal corticosteroids in patients with severe uncontrolled chronic rhinosinusitis with nasal polyps. Design, Setting, and Participants From August 9, 2022, to April 28, 2023, this randomized, double-blind, phase 3 clinical trial, conducted at 51 hospitals in China, enrolled adult patients with chronic rhinosinusitis with nasal polyps who had a history of systemic corticosteroid use or sinonasal surgery and a bilateral nasal polyp score of 5 or greater (on a scale of 0-8) and a weekly mean nasal congestion score of 2 or greater (on a scale of 0-3). Eosinophilic chronic rhinosinusitis with nasal polyps was defined as blood eosinophils of 6.9% or greater (without asthma) or 3.7% or greater (with asthma) or an eosinophil count of 55 per high-power field or greater or 27% or greater in nasal polyp tissue. Patient follow-up was completed on June 25, 2024. Interventions Four weeks after initiation of mometasone furoate nasal spray, 100 µg in each nostril daily, patients were randomized to receive subcutaneous stapokibart, 300 mg, or placebo (1:1) every 2 weeks for 24 weeks. Both groups then received stapokibart for 28 weeks. Main Outcomes and Measures Co–primary end points were changes from baseline in nasal polyp score (meaningful change threshold [MCT] ≥1 point) and nasal congestion score (MCT ≥0.5 points) at week 24 in all patients and in the population with eosinophilia. Results Among 180 patients randomized, 179 (mean age, 45 [SD, 12.9] years; 61 [34.1%] women) received at least 1 treatment dose (n = 90 for stapokibart; n = 89 for placebo). In the overall population, the least-squares (LS) mean change in nasal polyp score from baseline to week 24 in the stapokibart vs placebo groups was −2.6 vs −0.3 points, respectively, (LS mean difference, −2.3; 95% CI, −2.6 to −1.9; P < .001); in the population with eosinophilia, the change was −3.0 vs −0.4 points, respectively (LS mean difference, −2.5; 95% CI, −2.9 to −2.1; P < .001). The LS mean change in nasal congestion score from baseline to week 24 in the stapokibart vs placebo groups was −1.2 vs −0.5 points, respectively, in the overall population (LS mean difference, −0.7; 95% CI, −0.9 to −0.5; P < .001) and −1.3 vs −0.5 points, respectively, in the population with eosinophilia (LS mean difference, −0.8; 95% CI, −1.0 to −0.6; P < .001). Serious adverse events were rare (2.2% in the stapokibart group vs 1.1% in the placebo group). Higher rates of arthralgia (7.8% vs 0%) and hyperuricemia (5.6% vs 1.1%) were reported with stapokibart vs placebo, respectively. Conclusions and Relevance Among patients with severe chronic rhinosinusitis with nasal polyps treated with a daily intranasal corticosteroid, stapokibart reduced polyp size and severity of nasal symptoms at 24 weeks. Trial Registration ClinicalTrials.gov Identifier: NCT05436275