[Effects of baseline clinical characteristics on the efficacy of stapokibart in patients with seasonal allergic rhinitis: a post-hoc subgroup analysis].

Objective:To investigate the influence of different baseline clinical characteristics on the efficacy of stapokibart in patients with moderate-to-severe seasonal allergic rhinitis（SAR） and a peripheral blood eosinophil count ≥3×10⁸/L. Methods:Based on data from two randomized, double-blind, placebo-controlled trials（RCTs）, a post hoc subgroup analysis was conducted on patients with peripheral blood eosinophil counts≥3×10⁸/L who received an initial administration of 600 mg stapokibart or placebo. Efficacy endpoints were defined as the changes from baseline in the mean daily reflective total nasal symptom score（rTNSS）, mean daily reflective total ocular symptom score（rTOSS）, and Rhinoconjunctivitis Quality of Life Questionnaire（RQLQ） total score at weeks 2 and 4. An analysis of covariance（ANCOVA） model was used to calculate the least-squares mean（LSM） differences and 95% confidence intervals（CIs） between the two groups. Interaction tests were performed to evaluate the impact of various baseline characteristics（including demographic characteristics, allergen sensitization status, baseline symptom severity, etc. ） on treatment efficacy. Results:A total of 133 patients with moderate-to-severe SAR were included（61 in the stapokibart group and 72 in the placebo group）. Compared with the placebo group, the stapokibart group demonstrated significantly greater improvements from baseline in all clinical scores at weeks 2 and 4. The LSM differences for changes in mean daily rTNSS at weeks 2 and 4 were -1.3（95%CI -2.0 to -0.7; P<0.000 1） and -1.6（95%CI -2.3 to-0.8; P<0.000 1）, respectively. The LSM differences for changes in mean daily rTOSS were -0.7（95%CI -1.2 to -0.1; P=0.022 0） and -0.7（95%CI -1.3 to -0.1; P=0.020 0）, respectively. The LSM differences for changes in RQLQ scores were -0.9（95%CI -1.4 to -0.4; P=0.000 3） and -0.9（95%CI -1.4 to-0.5; P<0.000 1）, respectively. Subgroup analyses revealed that these efficacy improvement trends were generally consistent across patients with different baseline clinical characteristics, with no significant efficacy heterogeneity observed（all interaction P>0.05）. Conclusion:In moderate-to-severe SAR patients with elevated peripheral blood eosinophils, stapokibart significantly improves nasal symptoms, ocular symptoms, and quality of life. The treatment efficacy remains stable and consistent across various baseline clinical subgroups, providing evidence-based support for its broad clinical application in SAR patients. However, these findings warrant further validation in larger sample sizes.