Avanir Pharmaceuticals reported a positive outcome of its large, formal pharmacokinetic (PK) study of its investigational drug Zenvia (dextromethorphan/quinidine).

The objective of the formal PK study was to support identification of an alternative dosing formulation of Zenvia designed to deliver similar efficacy as observed in the first phase III clinical study in diabetic peripheral neuropathic (DPN) pain but with an improved safety and tolerability profile.

The study achieved its goal of identifying a new Zenvia dosing regimen that provides a similar pharmacokinetic profile of the dextromethorphan component, an improved adverse event profile and a lower overall exposure to quinidine compared to the previously studied doses. Avanir believes that these study results can be used to enhance its worldwide intellectual property protection and intends to release detailed data, including PK parameters, after they are incorporated into the Zenvia patent portfolio.

"We are extremely encouraged by the positive outcome of this study," said Dr Randall Kaye, Avanir's chief medical officer. "We have now identified a dosing regimen which, based on its observed PK parameters, we expect to demonstrate comparable efficacy with improved safety and tolerability relative to the regimens previously demonstrating efficacy in DPN pain. Notably, the new formulation of Zenvia offers a lower overall exposure to quinidine which should improve the cardiovascular risk profile. We look forward to engaging in discussions with the FDA with the goal of securing an SPA agreement for the next phase III study protocol. In addition, the data from the PK study further reinforces our confidence in the Zenvia 30/10 mg dose being studied in our current confirmatory phase III STAR trial in pseudobulbar affect (PBA)".

"I am very pleased that we were able to identify a new dose of Zenvia to take forward in our DPN pain programme," said Keith Katkin, Avanir's president and CEO. "In addition, this study provides us with important new information which we can use to strengthen our intellectual property protection for Zenvia. We look forward to releasing the detailed study results, including PK parameters, once we incorporate these PK findings into our Zenvia patent portfolio".

Zenvia is a combination of two well-characterized compounds: the therapeutically active ingredient dextromethorphan and the enzyme inhibitor quinidine, which serves to increase the bioavailability of dextromethorphan.