Vancouver, Canada (May 17, 2010) - Xenon Pharmaceuticals Inc. is pleased to announce that it has appointed Tarek S. Mansour as Executive Vice President, Research & Deveopment.

"We are delighted to welcome Tarek to the Xenon team," commented Simon Pimstone, Xenon's President and CEO. "Tarek is a world-class R&D executive whose experience in discovering products, a number of which are now on the market, will further enhance Xenon's capabilities. Tarek has had the unique experience of holding senior leadership positions within both biotech and more traditional pharmaceutical companies. His successful careers at Biochem Pharma and Wyeth Pharmceuticals (now Pfizer) have armed Tarek with best-in-class drug discovery and development practice and we are confident that Tarek will make a major contribution to Xenon's future innovative R&D efforts."

Dr. Mansour has spent nearly 25 years in the life sciences industry with positions at Biochem Pharma, and Wyeth Pharmaceuticals (now Pfizer). His most recent position at Wyeth Research was as VP, Chemical Sciences Head over multiple research sites. Dr. Mansour received his PhD in Chemistry from the University of Missouri - Columbia.

About Xenon

Xenon is a privately owned, clinical genetics-based drug discovery and development company engaged in developing small molecule therapies focusing in the areas of pain, cardiometabolic disease, and diseases of iron metabolism. Xenon has multiple products in phase 1 and 2 clinical development. For more information, visit the Company's website at www.xenon-pharma.com.

For more information regarding this press release, contact:

Xenon Contact

Dr. Simon Pimstone
President & CEO
Phone: (604) 484-3300
Email: ddunn@xenon-pharma.com

This release contains forward-looking statements that are not based on historical fact. These forward-looking statements involve risks, uncertainties and other factors that may cause the actual results, events or developments to be materially different from those expressed or implied by such forward-looking statements. Readers are cautioned not to place undue reliance on such forward-looking statements.