Targeting the interleukin-5 pathway improves cough hypersensitivity in patients with severe uncontrolled asthma

Background Capsaicin cough sensitivity (C-CS) reflects airway neuronal dysfunction and may be a significant biomarker of asthma. Although mepolizumab reduces cough in patients with severe uncontrolled asthma, it is unclear whether the cough reduction is associated with improved C-CS. Objective To clarify the effect of biologics on C-CS and cough-specific quality of life (QoL) in patients with severe uncontrolled asthma using our previous study cohort. Methods Overall, 52 consecutive patients who visited our hospital for severe uncontrolled asthma were included in the original study cohort, and 30 patients were eligible for this study. Changes in C-CS and cough-specific QoL were compared between patients treated with the anti–interleukin-5 (IL-5) pathway (n = 16) and those treated with other biologics (n = 14). The C-CS was measured as the concentration of capsaicin required to induce at least 5 coughs. Results Biologics significantly improved C-CS (P = .03). Anti–IL-5 pathway therapies significantly improved C-CS, whereas other biologics did not (P < .01 and P = .89, respectively). The C-CS improved significantly more in the anti–IL-5 pathway group than in the group treated with other biologics (P = .02). Changes in C-CS significantly correlated with improvements in cough-specific QoL in the anti–IL-5 pathway group (r = 0.58, P = .01) but not in the group treated with other biologics (r = 0.35, P = .22). Conclusion Anti–IL-5 pathway therapies improve C-CS and cough-specific QoL, and targeting the IL-5 pathway may be a therapeutic strategy for cough hypersensitivity in patients with severe uncontrolled asthma.