Further investigation of omeprazole warranted in patients with IPF
medwireNews: The proton pump inhibitor (PPI) omeprazole is well tolerated and may reduce cough frequency in patients with idiopathic pulmonary fibrosis (IPF), suggest results from a pilot phase II trial.
“Chronic cough is a major and disabling symptom affecting up to 80% of patients with IPF”, say A John Simpson, from Newcastle University in the UK, and co-investigators.
They explain that gastro-oesophageal reflux disease “has been postulated as a contributory factor to chronic cough in IPF and to the overall pathogenesis and progression of the disease”, and therefore the use of PPIs has been “commonplace in many countries”, despite a lack of evidence supporting their efficacy in this patient population.
As reported in Thorax, the 20 patients who were randomly assigned to receive oral omeprazole 20 mg twice daily experienced a reduction in geometric mean 24-hour cough frequency from 8.2 per hour at baseline to 4.6 per hour after a median treatment duration of 86.0 days.
By comparison, geometric mean 24-hour cough frequency decreased from 9.1 per hour to 8.3 per hour among the 20 patients treated with placebo for a median of 87.5 days, translating into a 39.1% lower frequency in the omeprazole group at the end of treatment after adjustment for baseline measurements.
Simpson and team caution that the difference in cough frequency between the two groups was not statistically significant, but note that their pilot trial was not designed with sufficient power to detect significant differences.
“The magnitude of the observed change in favour of omeprazole is considered clinically important, and is comparable to the effect size observed in studies reporting clinically meaningful reductions in objective cough frequency with other pharmacological treatments for chronic cough”, they add.
The study authors report that the PPI “appears to have been well tolerated”, with adverse events (AEs) “generally evenly distributed in the two groups”.
A total of 70% of patients treated with omeprazole experienced AEs, compared with 64% of those in the placebo group. The most commonly occurring AE in the omeprazole group was lower respiratory tract infection (26 vs 14%), followed by vomiting (9 vs 18%), urinary tract infection (9 vs 0%), abdominal pain (13 vs 14%) and cough (13 vs 5%).
Eight patients experienced nine serious AEs over the study period, including three cases of moderate-to-severe abdominal pain (one in the omeprazole group and two in the placebo group), as well as two deaths and three hospital admissions that were considered unrelated to treatment.
Together, these findings “support the pursuit of a larger multicentre trial to determine whether PPIs can reduce cough in IPF and provide a suite of background information to inform rational design of such a trial”, write the researchers.
And they conclude that future studies should “incorporate safety assessments in relation to respiratory infection and changes in lung function.”
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