Xenon Announces its Partner Genentech Has Advanced GDC-0310, a Second Nav1.7 Inhibitor for Pain, into Clinical Development

October 22, 2015 – Xenon Pharmaceuticals Inc.

BURNABY, British Columbia, October 22, 2015 — Xenon Pharmaceuticals Inc. (Nasdaq: XENE), a clinical-stage biopharmaceutical company, today announced that the Company’s partner Genentech, a member of the Roche Group, has advanced a second Nav1.7 inhibitor into clinical development. GDC-0310 is a selective, oral Nav1.7 small-molecule inhibitor, identified as part of the companies’ pain collaboration focused on the Nav1.7 target. Genentech has initiated a Phase 1 clinical trial in healthy volunteers for GDC-0310. Genentech is also developing GDC-0276, a selective, oral Nav1.7 small-molecule inhibitor for pain which is currently in a Phase 1 clinical trial.

“We are delighted with the advancement of a second Nav1.7 inhibitor into clinical development, underscoring the potential of this novel class of compounds as a new way to treat pain, and the productivity of our broad Nav1.7-focused discovery and development collaboration with Genentech,” said Dr. Simon Pimstone, President and Chief Executive Officer of Xenon. “We believe that Nav1.7 is a validated pain target and that both GDC-0276 and GDC-0310 are promising candidates.”

Since 2011, Xenon and Genentech have been collaborating to discover and develop selective oral inhibitors of Nav1.7 for the treatment of pain. Using its Extreme Genetics1 discovery platform, Xenon identified Nav1.7 as a drug target for pain after discovering that the Nav1.7 protein is deficient in the rare genetic disorder congenital indifference to pain, in which people are unable to feel pain. Nav1.7 appears to be involved in pain signaling and based on the human validation was selected as a key target for the development of novel analgesics.

About Xenon Pharmaceuticals Inc.
Xenon is a clinical-stage biopharmaceutical company discovering and developing a pipeline of differentiated therapeutics for orphan indications that it intends to commercialize on its own and for larger market indications that the company intends to partner with global pharmaceutical companies. Xenon has built a core enabling discovery platform, referred to as Extreme Genetics, for the discovery of validated drug targets by studying rare human diseases with extreme traits, including diseases caused by mutations in ion channels, known as channelopathies. Xenon’s Extreme Genetics platform has yielded the first approved gene therapy product in the European Union and a broad development pipeline and multiple pharmaceutical partnerships, including with Teva and Genentech. For more information, please visit www.xenon-pharma.com.

For More Information:
Contact:  Ian Mortimer Chief Financial Officer and Chief Operating Officer
Xenon Pharmaceuticals Inc.
Phone: 604.484.3300
Email: investors@xenon-pharma.com