R&D

FDA snubs Zogenix’s anti-seizure drug, not happy with some sloppy, inadequate R&D work

Nine months after Zogenix got a stock rally $ZGNX going by touting late-stage data for a new drug to prevent seizures due to Dravet syndrome, the FDA handed back their marketing application with a failing grade on inadequate and incomplete work. Officially, that’s called a refuse-to-file notice, which is always embarrassing. 

Stephen Farr

It’s not the end of the world, says Zogenix in a manner of speaking, but the agency was not happy that the biotech had submitted an incorrect version of a dataset with the NDA and faulted the company as “certain non-clinical studies were not submitted to allow assessment of the chronic administration of fenfluramine.”

Investors didn’t like it at all. The biotech, with a market cap of $2.2 billion, saw its shares tank on the news – plunging 32% after the bell.

The EMA, though, hasn’t had any problems with their application so far, accepting it for review with an expected decision in Q1 2020. And Stifle’s Paul Matteis is disconcerted by the whole thing.

We find the RTF letter for Fintepla disconcerting, somewhat bizarre, and reason enough to push back Fintepla US revenues to 2021 (at a slightly reduced probability-adjustment), conservatively assuming a meaningful delay. That being said, the preclinical toxicology ask from FDA is legitimately puzzling: remember, Zogenix has treated >200 Dravet patients out to 1-year and is currently conducting a Fintepla LGS trial that includes an OLE; you’d think that FDA would’ve asked for, or been comfortable with, prior preclinical toxicology studies before signing off on the conduct of extension trials.

It was a much different story back in the summer of 2018, when company execs touted positive data from their second Phase III study, noting that 43 patients on their drug had a 62.7% drop in seizures, compared to 1.2% in the placebo arm. At that point, the drug was shaping up as a direct competitor to GW Pharma’s Epidiolex, which wowed the industry with its cannabinoid approach to reducing seizures. That drug is billed as a blockbuster.

Zogenix’s drug fenfluramine, you might recall, was one half of the notorious diet drug fen-Phen. The biotech says they didn’t see any cardio issues in their small studies, but it does beg the question on just how high regulators may have raised the bar for an approval — or even acceptance of an NDA.

“We remain highly confident in Fintepla’s clinical profile demonstrated in the Phase 3 program in Dravet syndrome and are committed to advancing the product candidate as a potential new treatment option for this and other rare and often catastrophic epileptic encephalopathies,” said CEO Stephen Farr.


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Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT
Director of Operations
Atlas Venture Cambridge, MA

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