Baseline Characteristics Associated with Quartiles of Reslizumab Effect: Pooled Analysis Of Two Phase 3 Studies

RATIONALE: IV reslizumab (RES), a humanized anti-interleukin-5 monoclonal antibody, significantly reduced risk of asthma exacerbations and improved asthma control, lung function, and quality of life in patients with inadequately controlled eosinophilic asthma. This analysis evaluated baseline differences between patients in the highest and lowest quartiles of change in FEV₁ and patient reported outcome (PRO) measures.

METHODS: Data were pooled from two 52-week placebo-controlled trials of IV RES 3mg/kg (Q4wks) in patients aged ≥12 years with inadequately controlled eosinophilic (≥400 cells/μL) asthma. Baseline characteristics assessed included age, sex, BMI, baseline medications, ACQ-6, FEV₁, FVC, blood eosinophils, and age of asthma onset. Outcome measures were assessed at 52 weeks.

RESULTS: Patients (N=477) receiving RES achieved FEV₁ changes of ≥430mL (highest quartile) to ≤-100mL (lowest quartile); ACQ-6 changes of ≥-2.00 to ≤-0.67 and AQLQ changes of ≥2.00 to ≤0.44. For FEV₁ (highest vs lowest quartile), baseline characteristics that differed significantly were: proportion using OCS (22% vs 11%, p=0.0356), mean ACQ-6 (2.71 vs 2.39, p=0.0137), and mean blood EOS (858 vs 514 cells/µL, p=0.0008). For ACQ-6: baseline mean blood EOS (824 vs 551, p=0.0094) and mean age of asthma onset (30 vs 23 years, p=0.0044). For AQLQ: baseline mean ACQ-6 (3.08 vs 2.20, p<0.0001), mean blood EOS (829 vs 577, p=0.0183), and mean asthma age of onset (29 vs 23, p=0.0383).

CONCLUSIONS: Baseline blood EOS and ACQ-6 score consistently predicted patients in the highest quartile for lung function and PROs. OCS use predicted FEV₁ response; later age of onset predicted PRO responses.