Drug discovery and development firm Knopp Biosciences has announced positive top-line results from a Phase II dose-ranging trial of a novel oral drug, dexpramipexole, in patients with moderate-to-severe eosinophilic asthma.

Dexpramipexole is a selective inhibitor of eosinophil maturation, being developed by Knopp for asthma and other eosinophil-linked diseases.

The randomised, double-blind EXHALE study analysed the efficacy and safety of a daily dose of 75mg/150mg/300mg of oral dexpramipexole versus placebo in lowering blood eosinophil counts over 12 weeks.

The study was carried out at 28 centres and had 103 adult participants with moderate-to-severe eosinophilic asthma.

Data showed that the trial met its primary endpoint, with the drug showing a statistically significant, dose-dependent reduction in blood absolute eosinophil count (AEC) at 12 weeks versus placebo, along with the standard of care (SoC).

Inhaled corticosteroids plus a long-acting β2 agonist was the background SoC.

Furthermore, the magnitude of change in blood AEC was similar to the eosinophil depletion as observed in trials of dexpramipexole for other indications.

A reduction of eosinophil in blood with the use of oral dexpramipexole was linked to clinically significant improvement in lung function as measured by pre-bronchodilator FEV1.

All tested doses of the drug were observed to be well tolerated with no serious adverse events noted.

Knopp president and CEO Michael Bozik said: “This Phase II results strongly support the continued development of dexpramipexole as a potential first-in-class oral agent for the treatment of eosinophilic asthma.

“We expect future studies to determine the drug’s effects on severe asthma exacerbations, and to further assess its effects on lung function.”

In a Phase II hypereosinophilic syndrome trial, the drug was shown to significantly lower requirements for oral corticosteroids and caused durable disease remission in some patients.

In 2019, Knopp commenced patient enrolment in a Phase II clinical trial of dexpramipexole for the treatment of moderate-to-severe eosinophilic asthma.