Chasing GW's Epidiolex, Zogenix finally wins FDA nod for rare childhood epilepsy drug Fintepla

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The FDA has approved Zogenix's Fintepla, a challenger to GW Pharma's CBD med Epidiolex, to treat seizures associated with the rare epilepsy condition Dravet syndrome. (Raman Oza/Pixabay)(Raman Oza / Pixabay)

Zogenix has its first commercial product, a rare childhood epilepsy drug that could challenge GW Pharmaceuticals’ blockbuster hopeful Epidiolex.

On Thursday, the FDA approved Zogenix’s Fintepla to treat seizures associated with Dravet syndrome, a potentially life-threatening form of epilepsy, in patients 2 years of age and older.

The company’s commercial team has prepared a slate of digital tools for a rollout in July, when it will be available at the list price of $1,278 for a 30mL bottle, Zogenix chief commercial officer Ashish Sagrolikar said during a Friday conference call.

SVB Leerink analyst Marc Goodman pegged $700 million for Fintepla U.S. sales in 2030 based on a survey of physicians “who are excited to use the product both in on-label orphan epilepsy patients as well as in off-label refractive populations,” he wrote in a Friday note to clients.

“We like the epilepsy market for novel drugs because of physician enthusiasm for new agents based on a high unmet need, frequent switching and use of multidrug regimens, and relatively low payer pushback,” Goodman said.

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The FDA go-ahead was based on data from two phase 3 trials, in which Fintepla cut the monthly convulsive seizure frequency by 62.3% and 54% at 0.7 mg/kg/day and 0.4 mg/kg/day dosing, respectively, compared with placebo.

Fenfluramine, the active ingredient in Fintepla, was previously offered as part of an anti-obesity regimen known as Fen-Phen. However, the drug was pulled from markets across the globe after fenfluramine was linked to pulmonary hypertension and heart valve disease.

But even in a long-term, open-label extension trial in which Dravet patients were treated for up to three years, no such cardiac adverse events have been observed. Nevertheless, as a precaution, the FDA slapped a boxed warning on Fintepla’s label about the potential problems. It’s requiring cardiac imaging before, every six months during and after treatment of Fintepla, which is only available through an FDA-designated safety program.

RELATED: After Dravet hiccup, Zogenix's Fintepla prevails in phase 3 Lennox-Gastaut test

Fintepla didn’t exactly enjoy a smooth sail toward its final FDA nod. The agency first sent it a refusal to file letter in April 2019, noting certain nonclinical data were missing from the company's application and that the package contained an incorrect version of a clinical data set. Then, after accepting Zogenix’s second filing and putting the drug under priority review, the FDA pushed back its decision date by three months.

Those moves are all in the past, though. Now, the approval allows Zogenix to put up a fight against GW Pharma, whose cannabis-based med Epidiolex became the first FDA-approved Dravet therapy two years ago, bearing blockbuster hopes. Epidiolex raked in sales of $311.3 million in 2019.

Fintepla's heart concern, though expected, might hamper its competition with Epidiolex. Although as is the case with all antiepileptic drugs, both Fintepla and Epidiolex may increase the risk of suicidal thoughts or behavior, the GW drug doesn't have a safety signal as serious as a black box warning.

Meanwhile, Zogenix is eyeing Epidiolex’s other indication, in another rare epilepsy called Lennox-Gastaut syndrome. The biotech recently turned up positive result in LGS, but its stock fell sharply on the announcement anyway.

SVB Leerink’s Goodman noted that Fintepla’s 18.7% placebo-adjusted seizure reduction level was substantially lower compared with its performance in Dravet syndrome and likely fell below investors’ expectations. Still, he said Fintepla’s LGS data are in line with Epidiolex’s.

Zogenix is planning to meet with the FDA later this year to discuss a supplemental application in LGS.