Eisai sunsets development, access program for withdrawn obesity med in Dravet syndrome

In the wake of a market pull in obesity nearly five years ago, the other shoe has dropped for Eisai’s serotonin 2C receptor agonist lorcaserin.

Eisai has formally terminated a phase 3 study of lorcaserin as a potential adjunct treatment for patients with Dravet syndrome, a rare form of epilepsy that starts in infancy, according to the federal study repository clinicaltrials.gov. As of Nov. 8, Eisai still had lorcaserin listed (PDF) on its virtual pipeline, with Dravet syndrome the sole indication in which the drug was being tested.

In an emailed statement, Eisai told Fierce Pharma that it has made the “incredibly difficult decision to discontinue our PHNX Phase 3 study … and the Extended Access Program … exploring the use of lorcaserin as an adjunctive treatment in people living with Dravet Syndrome.”

Citing the advent of other FDA-approved Dravet treatments, a company spokesperson noted that it had become “exceedingly challenging” to recruit patients for Eisai’s phase 3 trial.

“The decision to discontinue the program is not related to any health or safety concerns,” the spokesperson added. “The closing of the lorcaserin clinical program weighs heavy on our hearts and we recommend that the limited number of patients currently participating in the studies contact their healthcare provider.”

The trial termination marks the end of lorcaserin development overall, with the drug not being tested in any other indications, the spokesperson confirmed.

Lorcaserin, which was developed by Arena Pharmaceuticals, began its commercial career as an obesity med dubbed Belviq. Eisai was originally a marketing partner with Arena on the med, which launched as part of a new class of weight loss drugs back in 2013. Eisai purchased exclusive rights to the drug from Arena for $23 million in January 2017.

Things took a turn, however, when Eisai in Feb. 2020 agreed to pull Belviq and its extended-release counterpart from U.S. shelves after the FDA flagged a higher right of cancer diagnoses in those treated with the drug as part of a postmarketing study.

Eisai subsequently tried to revive lorcaserin’s clinical prospects in Dravet syndrome after patients who were using the medication off-label petitioned the company to continue providing lorcaserin through an extended access program, according to a blog post on the Dravet Syndrome Foundation (DSF) website.

While the decision to end the lorcaserin trial and access program may come as a blow to Dravet patients, the move was largely to be expected, according to DSF.

Over the summer, the Foundation acknowledged Eisai’s decision to end its phase 3 trial and sunset its extended access program by November. At the time, the patient organization noted that trial participants would need to discontinue lorcaserin by October to complete their final study visits the following month.

DSF echoed Eisai’s statement about recruitment challenges in the Dravet trial, noting that the beginning of the study dovetailed with the FDA approval of Zogenix’s Fintepla—which also targets the serotonin pathway—potentially siphoning away enrollment momentum from Eisai’s study.

UCB ultimately purchased Zogenix and Fintepla for $1.9 billion in 2022.

Elsewhere, 2024 has seen a number of ups and downs when it comes to the development of novel Dravet syndrome treatments.

In early August, Stoke Therapeutics’ Dravet candidate STK-001 was freed from a partial FDA hold, paving the way for the biotech to test its experimental medication at multiple doses above 45 mg.

With the hold lifted, Stoke said at the time that it would continue forward on its mission to work with the FDA and other regulators on a finalized phase 3 study design by the end of the year.

Meanwhile, Takeda reported mixed results on its Ovid-partnered prospect soticlestat in June.

In a phase 3 trial in refractory Dravet syndrome, the cholesterol 24 hydroxylase inhibitor narrowly missed its primary endpoint of reduction from baseline in convulsive seizure frequency as compared to placebo but met multiple secondary objectives.