While some analysts figure Jazz Pharmaceuticals’ Epidiolex—sold as Epidyolex abroad—could surpass the blockbuster sales threshold by the end of the decade, the cannabidiol-based seizure drug has stumbled on its path to secure approval in Japan.
On Friday, Jazz revealed that its Epidiolex oral solution failed to mass muster in a late-stage study when used as an adjunct treatment for seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS) or tuberous sclerosis complex (TSC) in young Japanese patients.
Specifically, the study failed to meet the primary endpoint of a “pre-specified percentage change” in LGS, DS or TSC seizure frequency versus baseline during the treatment period, which ran for up to 16 weeks, Jazz explained in a release.
Despite the miss on the study’s main goal, Jazz stressed that numeric improvements were seen across primary and secondary endpoints. The company added that no new safety signals for the drug cropped up during the trial.
Jazz got its hands on Epidiolex when it purchased the drug’s developer, GW Pharmaceuticals, for $7.2 billion in May 2021. Epidiolex won its initial approval in the United States in 2018 to treat the rare forms of epilepsy LGS and DS in kids 1 year and older. In 2020, the FDA signed off on a label expansion for Epidiolex to include TSC.
Jazz’s phase 3 study looked at Epidiolex’s safety and efficacy in 62 Japanese patients between the ages of 1 and 18 years. The trial included an initial two-week titration period followed by a 14-week maintenance period, plus a safety evaluation period that ran for up to 52 weeks.
The trial is still ongoing, Jazz stated in its release.
“We believe the totality of the Epidyolex global data, including the findings from this trial, supports advancement of the program in Japan," Rob Iannone, M.D., EVP and global head of research and development at Jazz, said in a statement. "We are continuing to collect data in Japanese patients and plan to engage with regulatory authorities in Japan regarding a potential new drug application (JNDA).”
This isn’t the first time Jazz’s cannabis-based drug ambitions have stumbled after taking GW under its wing.
Back in the summer of 2022, the companies’ nabiximols oromucosal spray Sativex—formulated from extracts of the cannabis sativa plant containing tetrahydrocannabinol (THC) and cannabidiol (CBD)—flunked a phase 3 trial designed to help multiple sclerosis (MS) patients with spasticity.
As for Epidiolex, the drug continues to perform well on sales metrics. For all of 2023, the drug grew sales 15% to $845.5 million versus the previous year. And in 2024’s second quarter, Epidiolex brought home $247.1 million, a 22% increase over the same period in 2023.
The rare epilepsy drug is approved in more than 35 countries, with “additional launches and reimbursements anticipated through the end of 2024,” Jazz said in late July.
GlobalData expects Epidiolex could generate $1.3 billion by 2030, according to Clinical Trials Arena.