Second Phase 3 of Dravet Drug Completes Enrollment

Zogenix, Inc. announced today that the last patient has been randomized into the treatment period of Study 1504, its second Phase 3 clinical trial evaluating ZX008 (low-dose fenfluramine) as an adjunctive treatment for seizures in children and young adults with Dravet syndrome.

At the 71st American Epilepsy Society (AES) Annual Meeting in December, positive safety and efficacy data from the company’s Study 1 trial, exhibiting the drug’s ability to achieve a clinically meaningful benefit in the same indication, were presented.

Dravet syndrome is a pediatric epilepsy disorder in which a wide variety of seizure types plague the patient, and the condition is often associated with a high mortality rate. It typically begins in the first year of life of an otherwise healthy infant, and those affected can also experience developmental delays, and, at present, there aren’t any approved orphan drugs to treat the condition.

“The completion of patient randomization in Study 1504 represents another significant achievement in our ZX008 Phase 3 development program in Dravet syndrome,” said Stephen J. Farr, Ph.D., President and CEO of Zogenix in a press release. “We expect to announce top-line data from this study in the second quarter of this year. The data generated to date from the Phase 3 clinical program have further strengthened our confidence in the potential of ZX008 to become an important treatment option for the control of seizures in patients suffering from Dravet syndrome, a rare and catastrophic form of epilepsy.”

All subjects enrolled in Study 1504 are titrated to either an active dose of 0.5 mg/kg of ZX008 per day at a maximum of 20 mg per day or placebo for 3 weeks. Participants will be held at that fixed dose for 12 weeks of maintenance. Comparatively, in Study 1, patients were dosed with 0.8 mg/kg of ZX008 per day, which was proven to be superior to placebo as an adjunctive therapy.

The second Phase 3 is a double-blind, randomized, two-arm trial with an estimated 40 subjects per treatment group being conducted in the U.S. and 6 other countries. At all locations, participants are taking stiripentol as part of their baseline standard-of-care. In Study 1, concomitant use of stiripentol was excluded.

As in the first Phase 3, the primary efficacy measure is a comparison of the change in monthly convulsive seizure frequency between ZX008 and placebo during the treatment period compared with the baseline period.

Fenfluramine is an indirect serotonin agonist and sigma-1 antagonist that was once marketed as an anti-obesity drug. In 1997, it was taken off the market as the result of reports of valvular heart disease and pulmonary hypertension in women. At the time, the recommended dose was in the range of 60 mg - 120 mg per day.

In January 2016, Zogenix was granted fast track designation from the U.S. Food and Drug Administration, facilitating the development and expediting the review of the drug.

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