Jazz Pharmaceuticals’ oral cannabidiol drug Epidiolex has disappointed in a late-phase test in Japanese children with seizures, but the company will still file there based on its global dataset.
Regardless of the drug entering the Japanese market, analysts still expect it to collect blockbuster sales next year with its US and European approvals. In the second quarter of 2024, sales grew 22% compared to the same period in 2023, totaling $247.1 million.
The open-label Phase 3 Japan study did not meet its primary endpoint of percentage change from baseline in indication-associated seizure frequency at 16 weeks. But there were numeric improvements in the primary and several secondary endpoints, Jazz said.
Rob IannoneJazz is still “confident” about the drug’s clinical profile, which has been tested in five Phase 3 studies spanning more than 900 patients, head of R&D Rob Iannone said in a company release Thursday. The Phase 3 failure was “somewhat of a surprise,” because Epidiolex has shown “strong anti-seizure efficacy” in real-world patients, TD Cowen analysts added.
It’s not clear why the drug failed in Japanese patients, but differences in drug metabolism between East Asian and Western populations may have played a role, according to Stifel analysts.
The company will continue collecting data from Japanese patients. It studied Epidiolex in 62 children and adolescents in Japan aged 1 to 18 years with seizures due to Lennox-Gastaut syndrome, Dravet syndrome or tuberous sclerosis complex.
A Japan approval would open up a market of around 20,000 patients, Stifel analysts said. But even without tapping that opportunity, Epidiolex is still on track to reach $1.1 billion in sales next year, they added.
Epidiolex became the first cannabinoid-based drug to win FDA approval for seizures due to Lennox-Gastaut and Dravet syndromes back in June 2018. To prevent seizures, cannabinoid is thought to act on the brain’s G protein-coupled receptor 55 to limit the release of calcium into cells.
There are several other cannabinoid-based treatments being developed for movement-related CNS disorders. GW Pharmaceuticals — a subsidiary of Jazz — has nabiximols in a Phase 3 trial for people with spasticity due to multiple sclerosis. Echo Pharmaceuticals also has a Phase 1 oral tablet asset called arvisol for epilepsy and schizophrenia.