Pharmaceutical firm Zogenix has concluded patient enrolment in a Phase III clinical trial assessing Fintepla (ZX008, fenfluramine) to treat seizures associated with Lennox-Gastaut Syndrome (LGS), a severe form of childhood-onset epilepsy.

A formulation of fenfluramine hydrochloride oral solution, Fintepla secured orphan drug designation in both the US and EU.

The Phase III study is designed to assess two fixed doses of Fintepla as adjunctive therapy for seizures in children and adults with LGS.

A total of 263 participants have been enrolled for the multi-national, randomised, double-blind, placebo-controlled trial.

Subjects are randomised to receive 0.2mg/kg or 0.8mg/kg a day Fintepla or placebo for a two-week dose titration period before receiving a fixed dose for 12 weeks of maintenance therapy.

The primary endpoint of the study is the change in the number of seizures that cause drops between baseline and the combined titration and maintenance periods with the 0.8mg/kg/day dose versus placebo.

The trial’s key secondary endpoints include the change in the number of drop seizures at the 0.2mg/kg a day dose, compared to placebo, and the proportion of patients experiencing a 50% decrease in drop seizures.

Patients completing the maintenance treatment may be eligible for a 12-month open-label extension study to assess the long-term safety, tolerability, and effectiveness of the investigational drug.

Top-line results from the Phase III trial are expected to be available in the first quarter of next year.

Zogenix executive vice-president and chief development officer Gail Farfel said: “Based on the compelling data generated in the previously completed Phase II study, we believe this promising drug candidate has the potential to become an important new treatment option for the control of seizures in patients suffering from LGS.”

Fintepla is also being developed in Japan to treat seizures associated with Dravet syndrome.