Managing unexplained chronic cough in adults: what are the unmet needs?

Randomised trial of the P2X3 receptor antagonist sivopixant for refractory chronic cough

Background

The purinoceptor subtype P2X₃ has been shown to have significant involvement in the cough reflex; the heterotrimer version of the purinoceptor (P2X_2/3) has been implicated in taste disturbance. The most advanced clinical candidate antagonist gefapixant has low selectivity among P2X₃ receptors and induced taste disturbance, whereas newly developed sivopixant has high selectivity towards P2X₃versus P2X_2/3.

Methods

In a phase 2a, randomised, double-blind, placebo-controlled, crossover, multicentre study, adult patients with refractory or unexplained chronic cough received oral sivopixant 150 mg or placebo once daily for 2 weeks, followed by a 2–3-week washout period, and then crossed over to placebo or sivopixant for 2 weeks. Efficacy and safety of sivopixant were evaluated.

Results

Of 31 randomised patients, 15 in the sivopixant-first group and 15 in the placebo-first group completed the study. After 2 weeks of treatment, the placebo-adjusted ratios of the average hourly number of coughs to baseline during daytime (primary end-point) and over 24 h (secondary end-point) were −31.6% (p=0.0546) and −30.9% (p=0.0386), respectively. Sivopixant also improved health-related quality of life. Treatment-related adverse events occurred in 12.9% and 3.2% of patients during sivopixant and placebo administration, respectively. Mild taste disturbance occurred in two patients (6.5%) during sivopixant administration.

Conclusions

Sivopixant reduced objective cough frequency and improved health-related quality of life, with a low incidence of taste disturbance, among patients with refractory or unexplained chronic cough.

This study shows the efficacy of a highly selective P2X₃ receptor antagonist to reduce cough frequency, with low incidence of taste disturbance. Sivopixant may be a promising therapeutic option for refractory or unexplained chronic cough.https://bit.ly/3awojQH

Pulmonary manifestations of gastroesophageal reflux disease

INTRODUCTION

Gastroesophageal reflux disease (GERD) is a widespread condition with a significant impact on the quality of life and healthcare resources. In addition to its gastrointestinal problems, GERD has been linked to a variety of respiratory diseases either as a direct cause, or as a risk factor to the inability to control or worsening of the disease.

AREAS COVERED

We performed a literature search in the PubMed database for articles addressing GERD and pulmonary diseases. This review will discuss several different pulmonary diseases affected by GERD ranging from upper airway including chronic cough, vocal cord dysfunction, lower airway diseases including COPD, asthma, and bronchiolitis obliterans syndrome to parenchymal diseases such as interstitial lung diseases. The review will discuss several different pulmonary manifestations of GERD and their contribution to patient mortality and morbidity. It will also review the mechanisms leading to these diseases, diagnostic workup, and the role of the available treatment options.

EXPERT OPINION

GERD is often overlooked as a cause of respiratory symptoms and illnesses. The literature is sparse on the relation between GERD and respiratory diseases such as interstitial lung diseases and bronchiolitis obliterans including its role in pathogenesis, mechanisms of lung injury, and whether treatment of GERD is effective in managing such illnesses.