Another hiccup for GW Pharma's seizure drug rival, as Zogenix discloses FDA review delay
Zogenix has had a troubling 2020 so far. Earlier this month, its experimental seizure drug met the main goal in a pivotal study in patients with Lennox-Gastaut Syndrome, but the company saw its shares plummet after the magnitude of the therapy’s effect fell short of Wall Street expectations. On Thursday, the drug developer said that the FDA had extended the review of the drug in patients with Dravet syndrome by three months.
Last April, Zogenix said the FDA had rebuffed reviewing the drug’s marketing application for Dravet patients in a refuse-to-file letter, citing the lack of certain non-clinical studies key for the assessment of chronic administration of the drug as well as an incorrect version of a clinical dataset. In November, the FDA accepted the company’s resubmitted application, and the agency was expected to make its final decision by March 25.
However, after Zogenix recently submitted additional efficacy data on the drug — to be branded Fintepla — at the behest of the US regulator. That information was constituted as a major amendment, which pushed the FDA’s decision date to June 25, the company said.
When Stifel’s Paul Matteis spoke to Zogenix management, executives told him that the information in question was around an efficacy analysis, and not focused on the drug’s safety profile or toxicity studies. The company also suggested that they had “zero indication” that the FDA was planning an advisory committee meeting.
“We asked, just to make sure, whether or not these efficacy analyses were related to an interpretation of the PhIII trials as successful or not: They affirmed this is not the case, the ask is not about data integrity, and thus the additional analyses that were submitted to the agency sound to us like they’re probably less about whether or not the drug works, and therefore probably less about actual approvability,” Matteis wrote in a note.
If approved, Fintepla, which is one-half of the notorious axed prescription weight-loss cocktail fen-phen, will compete with GW Pharmaceuticals’ pioneering cannabis-derived Epidiolex — which is approved for both Dravet and LGS.
“To be fair this isn’t the first hiccup with the submission, given that there was an RTF last Spring. Some investors might look at a pattern here and get worried that there’s something else going on beyond the surface. We obviously can’t be 100% certain. But when we look at the clinical data, the efficacy of Fintepla in Dravet looks highly differentiated, and the safety profile of the drug — as assessed under FDA guidelines — looks better than we had always expected as it relates to CV risk,” Matteis added.
“(W)e assume a 80% probability-of-approval, and in the mid-$20s, we think shares are discounting the revenue potential of Fintepla in Dravet and are ascribing little-to-no credit in LGS, where, even despite efficacy not living up to expectations, still is a real market for this product.”
Echoing Stifel’s commentary, SVB Leerink analyst Marc Goodman said he was still positive about the approvability of the drug, despite the delay.
“(T)he FDA delays that are major amendments are usually because the FDA wants to approve the product, which is good precedent,” he wrote in a note, noting that most investors are concerned about safety only because of the history of fen-phen.
But Zogenix investors appeared dismayed by the announcement. The California-based company’s stock $ZGNX tumbled about 19% to $21.20 in morning trading.