UPDATE: Jazz halts sleep disorder med trial over 'visual disturbances' and CV effects

Jazz Pharmaceuticals is pressing pause on a phase 1 sleep disorder med due to adverse events despite one executive saying that it “achieved proof of concept.” 

The comments were relayed by Chief Medical Officer Kelvin Tan at a conference hosted by Evercore ISI on Tuesday and poured cold water on the near-term prospects of the asset recently licensed from Sumitomo Pharma. Tan said that the drug, JZP441, demonstrated proof-of-concept in healthy volunteers as measured by the Maintenance of Wakefulness Test (MWT).

However, reports of “visual disturbances” and cardiovascular effects have forced the company to pause the trial while they investigate further. 

“This is early and emerging data but we’ve taken this decision,” Tan said. He added that despite the pause, orexin-2 receptor agonists remain a priority class and the company has a “backup” program in tow. Executives wouldn’t go as far as to fully terminate the paused asset, saying they’re looking to further investigate the side effects and how to potentially mitigate them. 

“It does require additional work,” President and Chief Operating Officer Renée Galá said at the conference. Jazz told Fierce Biotech in a statement that the company has not observed any liver toxicity signals. 

Jazz grabbed onto commercialization rights for most parts of the world from Sumitomo some 18 months ago, costing Jazz $50 million in upfront cash with more than $1 billion on the table in biobucks. At the time of the deal, the drug was in the middle of a phase 1 trial among healthy volunteers study in Japan.

The initial plan was to test JZP441 as a treatment for narcolepsy, though Jazz felt it likely had application in other sleep disorders, as well. The drug targets the orexin-2 receptor in the hopes of stimulating orexin signaling. Orexin is a neuropeptide involved with regulating sleep and wakefulness. 

Takeda may have been a canary in the coal mine. The Japanese pharmaceutical was working on its own candidate but scrapped further development in July 2022 citing the risk-benefit profile. That final blow followed Takeda’s previous decision to halt two studies after a safety signal arose. 

At Tuesday’s conference, Tan made sure to swiftly transition from bad news to good, announcing that Jazz planned to initiate rolling submission of its bispecific antibody zanidatamab before the end of the year. The company is seeking accelerated approval as a second-line treatment for patients with biliary tract cancer, with the application set to be completed by the first half of 2024. 

Editor's note: This article was updated with a statement from Jazz and to correct the proof-of-concept assessment for JZP441 in a phase 1 trial. It was measured by the Maintenance of Wakefulness Test, not normal wake time.