Jazz's Epidiolex underperforms in Japanese study despite rising sales

Jazz Pharmaceuticals' cannabidiol-based seizure medication, Epidiolex, encountered a setback in its approval process in Japan. Despite expectations that Epidiolex could become a blockbuster drug by the end of the decade, it failed to achieve its primary goal in a late-stage clinical study in Japan. The study focused on its efficacy as an additional treatment for seizures associated with Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS), and tuberous sclerosis complex (TSC) in young patients.

The trial did not meet its main endpoint, which was a predetermined percentage change in seizure frequency from the baseline during a treatment period lasting up to 16 weeks. Jazz Pharmaceuticals emphasized that numeric improvements were observed across both primary and secondary endpoints, although the primary goal was not achieved. Additionally, no new safety concerns emerged during the trial, which included 62 Japanese patients aged between 1 and 18 years. The trial comprised a two-week titration period, a 14-week maintenance period, and a safety evaluation period that extended up to 52 weeks.

Jazz Pharmaceuticals acquired Epidiolex in May 2021 through the $7.2 billion purchase of GW Pharmaceuticals, the drug's original developer. Epidiolex initially received FDA approval in the United States in 2018 for treating LGS and DS in children aged one year and older. The FDA later expanded the drug's label in 2020 to include TSC.

Although the study didn't meet its primary endpoint, Jazz Pharmaceuticals remains optimistic about Epidiolex's potential in Japan. The company plans to continue collecting data from Japanese patients and intends to discuss a potential new drug application with Japan's regulatory authorities. Rob Iannone, M.D., EVP and global head of research and development at Jazz, expressed confidence in the global data supporting the advancement of Epidiolex in Japan.

This is not the first challenge Jazz Pharmaceuticals has faced with cannabis-based treatments. In the summer of 2022, another product, Sativex, failed a phase 3 trial aimed at treating spasticity in multiple sclerosis (MS) patients. Sativex, an oromucosal spray, contains extracts from the cannabis sativa plant, including tetrahydrocannabinol (THC) and cannabidiol (CBD).

Despite the setback in Japan, Epidiolex continues to achieve strong sales figures. For the entire year of 2023, Epidiolex's sales grew by 15%, reaching $845.5 million compared to the previous year. In the second quarter of 2024 alone, the drug generated $247.1 million, marking a 22% increase from the same period in 2023. Epidiolex is approved in over 35 countries, and additional launches and reimbursements are expected through the end of 2024. According to Clinical Trials Arena, GlobalData projects that Epidiolex could generate $1.3 billion by 2030.

In summary, while Epidiolex encountered a hurdle in its Japanese clinical trial, Jazz Pharmaceuticals remains committed to advancing the drug's approval process in Japan. The company is continuing to gather data and plans to engage with regulatory authorities. Meanwhile, Epidiolex maintains strong sales performance globally and holds promise for future growth.