The cytokine IL-5 induces maturation, recruitment, and activation of eosinophils. Castro et al randomized 106 patients with asthma and positive sputum eosinophils to receive either infusions of reslizumab (monoclonal antibody, IL-5 inhibitor) or placebo at time 0 and weeks 4, 8, and 12. They stratified patients according to their Asthma Control Questionnaire score (<=2 or >2 on the 7 point scale, with 1.0 being controlled).
At week 15, the reslizumab group’s ACQ scores had fallen 0.7 points (0.5 = clinically meaningful), while the placebo’s had dropped 0.3, just missing stat.significance (p=0.054). FEV1 was improved by 260 mL over placebo (p=0.002). There were fewer exacerbations in the reslizumab group, not reaching significance (8% vs. 19% in placebos). Reported adverse effects were minimal. Ception Therapeutics funded the study and had a large role in its design and interpretation.