UK-based biopharmaceutical firm Verona Pharma has completed patient enrolment in a Phase IIb clinical trial of nebulised ensifentrine (RPL554) to treat moderate-to-severe chronic obstructive pulmonary disease (COPD).

Ensifentrine exhibits both bronchodilator and anti-inflammatory effects by inhibiting the phosphodiesterase 3 (PDE3) and phosphodiesterase 4 (PDE4) enzymes.

The nebulised formulation of the drug is being developed as a maintenance therapy of COPD and as a treatment for CF. It is intended to act as an add-on to common therapies used to address acute COPD exacerbations.

In the randomised, double-blind, placebo-controlled dose-ranging Phase IIb trial, the drug’s safety and efficacy are being evaluated in 416 patients at 46 sites across the US.

Participants will receive a 0.375mg, 0.75mg, 1.5mg or 3mg dose of nebulised ensifentrine or placebo as an add-on treatment to a long-acting anti-muscarinic (LAMA), inhaled tiotropium, twice daily over four weeks.

The primary endpoint of the study is the improvement in lung function, measured as peak forced expiratory volume in one second (FEV1) at week four.

The trial will also assess other lung function measures and COPD symptoms along with quality of life outcomes.

Data from the trial is expected to be reported by the end of this year and the end-of-Phase II meeting with the US regulator is anticipated in the first half of next year.

Verona Pharma CEO Jan-Anders Karlsson said: “We expect this second Phase II study with nebulised ensifentrine in COPD to help inform our planned Phase III clinical development programme, which we expect to start in 2020.

“Millions of COPD patients urgently need better treatments as they remain symptomatic despite maximum treatment with currently available therapies. We believe ensifentrine, with its unique mode of action and clinical profile, will have an important role in treating these patients.”

The company plans to initiate Phase III studies of the drug next year.