Aprepitant for Cough in Lung Cancer: A Randomized Placebo-controlled Trial and Mechanistic Insights

Rationale: Effective cough treatments are a significant unmet need in patients with lung cancer. Aprepitant is a licensed treatment for nausea and vomiting, which blocks substance P activation of NK-1 (neurokinin 1) receptors, a mechanism also implicated in cough. 

Objectives: To assess aprepitant in patients with lung cancer with cough and evaluate mechanisms in vagal nerve tissue. 

Methods: Randomized double-blind crossover trial of patients with lung cancer and bothersome cough. They received 3 days of aprepitant or matched placebo; after a 3-day washout, patients crossed to the alternative treatment. The primary endpoint was awake cough frequency measured at screening and Day 3 of each treatment; secondary endpoints included patient-reported outcomes. In vitro, the depolarization of isolated guinea pig and human vagus nerve sections in grease-gap recording chambers, indicative of sensory nerve activation, was measured to evaluate the mechanism. 

Measurements and Main Results: Twenty patients with lung cancer enrolled, with a mean age 66 years (67.7); 60% were female and 80% had non–small cell cancer, 50% had advanced stage, and 55% had World Health Organization performance status 1. Cough frequency improved with aprepitant, reducing by 22.2% (95% confidence interval [CI], 2.8–37.7%) over placebo while awake (P = 0.03), 30.3% (95% CI, 12.7–44.3) over 24 hours (P = 0.002), and 59.8% (95% CI, 15.1–86.0) during sleep (P = 0.081). Patient-reported outcomes all significantly improved. Substance P depolarized both guinea pig and human vagus nerve. Aprepitant significantly inhibited substance P–induced depolarization by 78% in guinea pig (P = 0.0145) and 94% in human vagus (P = 0.0145). 

Conclusions: Substance P activation of NK-1 receptors appears to be an important mechanism driving cough in lung cancer, and NK-1 antagonists show promise as antitussive therapies.