- With another late-stage clinical win under its belt, California biotech Zogenix expects to submit an approval application for its epilepsy drug in the fourth quarter.
- Topline results from Study 1504, the second of two pivotal trials testing ZX008 in patients with a rare form of epilepsy called Dravet syndrome, found a 55% greater reduction in average monthly convulsive seizures for patients taking the drug compared to placebo.
- ZX008 also met all key secondary endpoints, as the portion of patients who saw their monthly convulsive seizures fall by at least one-half or three-fourths was significantly higher in the experimental group than the placebo group. The incidence of serious side effects was similar between both groups, with 14% of patients in the former and 15.9% in the latter demonstrating at least one treatment-emergent serious adverse event.
Dravet syndrome affects about one in every 16,000 people living in the U.S., yet no treatment for the disease ever secured Food and Drug Administration approval — until last month, that is, when GW Pharmaceuticals broke the dry spell by getting a thumbs up for Epidiolex (cannabidiol).
Noteworthy too is that Epidiolex was the first drug derived from the marijuana plant to gain an FDA backing. That title, though, has pushed GW to hold off on launching the new product until it gets downgraded from its current Schedule 1 status. Steven Schultz, vice president of the company's investor relations, said it's likely regulators will make Epidiolex a Schedule 4 or 5 drug, and that formal pricing decisions will happen after such a change.
The wait time may be advantageous for rival therapy ZX008 (fenfluramine hydrochloride), which is heading toward market at a rapid clip. Leerink analyst Geoffrey Porges believes the candidate, which carries Orphan Drug and Breakthrough Therapy designations in the U.S., will likely launch in mid-2019.
Pricing, however, could complicate things. While Zogenix's drug has notched a strong efficacy profile in the clinic, its active ingredient fenfluramine raised safety concerns back in the 1990s due to concerns it negatively affected cardiovascular health. In fact, the concerns became so great that fenfluramine was pulled from market.
What's more, the orphan designation attached to ZX008 could contribute to a more expensive price tag.
"We receive many questions from investors about Zogenix' ability to price ZX008 at ~$100k/year levels similar to other orphan drugs," Porges wrote in an April 18 investor note that followed discussions with Zogenix leadership, including CEO Stephen Farr.
"Dr. Farr believes that although fenfluramine was originally approved several decades ago, the fact that it is not available today, along with the extensive efficacy and cardiac safety work that Zogenix has done makes this situation different than other reformulation examples that have caused pricing controversies in the past."
While Farr didn't give specific pricing numbers, Porges added that it "is clear that Zogenix plans to price ZX008 at a significant premium to other anti-epileptic drugs that are often used off-label and have shown less benefit in Dravet."
Whatever price Zogenix puts on ZX008, it will surely be tied — at least in part — to the fact that neither late-stage Dravet syndrome study found any patient developing heart valve disease or pulmonary hypertension due to treatment. That lack of safety signals "supports the case that safety will not be a barrier for the approval of this medicine," Porges wrote in a July 12 investor note.
Investors appear optimistic about the drug's regulatory chances as well. Zogenix shares were up nearly 22% to $56.45 apiece at market's open Thursday.