Bayer's Investigational P2X3 Antagonist Eliapixant Meets Primary Efficacy Endpoint in Phase 2b Trial for Refractory Chronic Cough

Compiled and Translated by | newborn

On August 3, Bayer announced positive results from a Phase IIb clinical study. This international, placebo-controlled, randomized, double-blind, parallel-group, dose-finding study was designed to evaluate the efficacy and safety of the oral, potent, and selective P2X3 receptor antagonist eliapixant (BAY1817080) compared with placebo in patients with refractory chronic cough (RCC).

The study enrolled over 300 patients, who were randomized to receive eliapixant tablets at doses of 25 mg, 75 mg, or 150 mg, or placebo, administered orally twice daily for 12 weeks. The total observation period for each patient was approximately 18 weeks. During the study, patients were required to wear a digital device to record coughs and complete daily questionnaires to subjectively document symptoms. Blood samples were collected to monitor the safety of the study drug and to measure plasma drug concentrations. The primary efficacy endpoint was the hourly cough frequency over 24 hours (based on the average hourly cough count from 24-hour audio recordings).

The results demonstrated that after 12 weeks of treatment, compared with the placebo group, the eliapixant treatment group showed a statistically significant improvement in the primary efficacy endpoint. Throughout the trial, eliapixant exhibited a favorable safety and tolerability profile. Detailed data from this study will be presented at an upcoming scientific meeting.

Chemical structure of Eliapixant (Image source: medkoo.com)

Globally, the prevalence of chronic cough is approximately 10%. Refractory chronic cough (RCC) affects 1–5% of the global population. Rather than serving as a protective airway mechanism, it is driven by cough hypersensitivity syndrome. RCC significantly disrupts patients' daily lives, causing them to cough 10 to 100 times per hour in the absence of external triggers, and profoundly impacts both the physical and psychological dimensions of their quality of life. In many cases, the condition follows a prolonged course, with an average time to diagnosis exceeding 8 years. Currently, only limited therapeutic options are available to manage this condition, underscoring a significant unmet medical need for novel, effective treatments.

Eliapixant is an oral, potent, and selective P2X3 receptor antagonist. The P2X3 receptor is a key regulator of afferent nerve fiber signaling and is believed to play a central role in neuronal hypersensitivity disorders such as cough hypersensitivity syndrome. P2X3 receptor antagonists block the receptor to reduce peripheral nerve fiber sensitivity.

The P2X3 receptor antagonist originated from a former strategic research alliance with Evotec SE, which initially focused on endometriosis. In addition to refractory chronic cough, Bayer is currently evaluating the therapeutic efficacy of eliapixant for endometriosis, overactive bladder, and neuropathic pain in Phase II clinical trials.

Reference: Bayer’s investigational P2X3 antagonist meets primary efficacy endpoint and shows favorable safety and tolerability profile