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.