Patients have begun receiving Verona Pharma’s experimental respiratory drug RPL554 in a Phase IIb trial assessing its potential as a maintenance therapy for chronic obstructive pulmonary disease (COPD).

RPL554 is a first-in-class, inhaled, dual inhibitor of the enzymes phosphodiesterase 3 and 4 (PDE3/PDE4) with anti-inflammatory as well as bronchodilatory properties, currently being developed by the firm for the treatment of COPD and cystic fibrosis.

Previous clinical trials of the drug in patients with COPD have shown that it can induce statistically significant improvements in lung function as compared to placebo as well as other clinically meaningful and statistically significant improvements in lung function when added to two commonly used bronchodilators as compared to either bronchodilator administered as a single agent.

The firm is planning to enrol around 400 patients in the new four-week, dose-ranging trial to assess efficacy, safety, and dose-response of nebulised RPL554 as a maintenance treatment for the disease.

The primary endpoint is improvement in lung function with RPL554 compared to placebo, as measured by FEV1, a standard measure of exhaled breath volume used to evaluate respiratory function.

The trial is being performed at a number of sites across Europe under Verona’s global strategic services agreement with QuintilesIMS, with the latter serving as sole provider of core clinical trial services for the firm’s RPL554 clinical development programmes.

“Dosing our first patients in this larger four-week Phase IIb trial is an important step forward in the evaluation of nebulised RPL554 as a novel therapy for COPD patients with significant unmet medical needs,” said Jan-Anders Karlsson, Verona’s chief executive.

“The clinical data generated to date and the mechanism of action of RPL554 makes it a promising first-in-class treatment option.”

Top-line results from the study are expected in the second half of 2018.