After a rocky ride, Zogenix’s Fintepla turned up encouraging phase 3 data in a second type of rare childhood epilepsy. The drug beat placebo at cutting seizure frequency for patients with Lennox-Gastaut syndrome who typically experience dozens of seizures each month.
The phase 3 study pitted two doses of Fintepla against placebo in 263 patients aged two to 35 years old whose seizures were uncontrolled despite taking one or more anti-epileptic medicines. The patients suffered a median baseline of 77 drop seizures each month, so called because a sudden loss of muscle strength can cause a person to drop to the floor. After 12 weeks of treatment, the higher dose of Fintepla reduced the number of drop seizures patients experienced per month by a median 26.5% compared to 7.8% of patients taking placebo. The lower dose decreased seizure frequency, too, but did not hit statistical significance.
More patients taking the higher dose of Fintepla, 0.7 mg per kilogram of body weight per day, saw their monthly drop seizures reduce by at least half: 25.3% versus 10.3% for patients on placebo. Patients who completed the 12-week portion of the study could choose to continue on to a yearlong, open-label extension study, which will gather long-term safety, tolerability and efficacy data.
Though the data are encouraging, Zogenix’s stock took a 30% dip Friday morning. The latest reveal comes 10 months after the FDA refused to consider Fintepla’s new drug application for Dravet syndrome, another type of rare childhood epilepsy. The agency said the application was missing some studies but also included some clinical data that shouldn't have been there—a mistake that essentially stopped the review in its tracks.
Fintepla, formerly known as ZX-008, is a low dose of fenfluramine, a drug that blocks the reuptake of serotonin. Zogenix is developing it for Doose syndrome and other rare epilepsies in addition to Dravet and Lennox-Gastaut syndromes. These epilepsies tend to appear in childhood, have a higher mortality rate than other types of epilepsy and do not respond to many of the drugs typically used to treat seizures.
“LGS is a rare and severe form of epilepsy where nearly all patients have highly treatment resistant and lifelong seizures. As a result, the frequent falls and injuries, and also the cognitive impairment, limit the quality of life for patients and caregivers, even with current treatment options,” said the study’s principal investigator, Kelly Knupp, M.D., of Children’s Hospital Colorado, in a statement. “The results observed in this placebo-controlled study are indicative of the potential of fenfluramine to treat patients with refractory LGS. If approved, Fintepla could represent an important new treatment option for these patients and their families in need.”
If approved, Fintepla would join Epidiolex, GW Pharma’s cannabis-based treatment for Dravet and Lennox-Gastaut syndromes. In 2018, it became the first medicine of its kind to be approved in the U.S.