Partnered Program with Neurocrine Biosciences, Inc.

In December 2019, we entered into a license and collaboration agreement with Neurocrine Biosciences to develop treatments for epilepsy. Neurocrine Biosciences has an exclusive license to XEN901, now known as NBI-921352, a clinical stage selective Nav1.6 sodium channel inhibitor, and an exclusive license to pre-clinical compounds for development, including selective Nav1.6 inhibitors and dual Nav1.2/1.6 inhibitors. The agreement also included a multi-year research collaboration to discover, identify and develop additional novel Nav1.6 and Nav1.2/1.6 inhibitors.

NBI-921352 is a potent, highly selective Nav1.6 sodium channel inhibitor being developed to treat pediatric patients with SCN8A developmental and epileptic encephalopathy (SCN8A-DEE) and other potential indications, including the treatment of focal-onset seizures in adults.

Clinical Development

Neurocrine Biosciences is conducting a Phase 2 clinical trial evaluating NBI-921352 in adult patients with focal onset seizures, with data expected in the fourth quarter of 2023. In addition, a Phase 2 clinical trial is underway evaluating NBI-921352 in patients aged between 2 and 21 years with SCN8A developmental and epileptic encephalopathy (SCN8A-DEE).

In September 2021, Xenon received an aggregate milestone payment of $10.0 million in the form of cash and an equity investment based on the regulatory approval of a clinical trial application in Europe for NBI-921352 for focal-onset seizures in adults. In January 2022, Xenon received an aggregate of $15.0 million in the form of cash and an equity investment due to our collaboration achieving another regulatory milestone based on the FDA’s acceptance of a protocol amendment to expand the study population to include subjects aged between 2 and 11 years in the ongoing NBI-921352 Phase 2 clinical trial in pediatric patients with SCN8A-DEE.