NBI-921352 (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, or SCN8A-DEE, and other potential indications, including adult focal epilepsy.

Clinical Development

Neurocrine Biosciences has indicated that it anticipates filing an IND application with the FDA in the near-term in order to start a Phase 2 clinical trial in SCN8A-DEE patients in the second half of 2020.


Xenon is eligible to receive up to $25 million upon the FDA acceptance of an IND for NBI-921352, with 55% of the amount in the form of an equity investment in Xenon at a 15% premium to Xenon’s 30-day trailing volume weighted average price at that time.