Exhibit 99.1
Joint Filing Agreement
The undersigned hereby agree that the Statement on Schedule 13G dated November 14, 2014 with respect to the Common Shares of Xenon Pharmaceuticals Inc., and any further amendments thereto executed by each and any of the undersigned shall be filed on behalf of each of the undersigned pursuant to and in accordance with the provisions of Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended.
Dated: November 14, 2014
| BIOTECHNOLOGY VALUE FUND, L.P. | INVESTMENT 10, L.L.C. | |||
| By: | BVF Partners L.P., its general partner | By: | BVF Partners L.P., its investment adviser | |
| By: | BVF Inc., its general partner | By: | BVF Inc., its general partner | |
| By: | /s/ Mark N. Lampert | By: | /s/ Mark N. Lampert | |
| Mark N. Lampert | Mark N. Lampert | |||
| President | President | |||
| BIOTECHNOLOGY VALUE FUND II, L.P. | MSI BVF SPV, LLC | |||
| By: | BVF Partners L.P., its general partner | By: | BVF Partners L.P., its investment adviser | |
| By: | BVF Inc., its general partner | By: | BVF Inc., its general partner | |
| By: | /s/ Mark N. Lampert | By: | /s/ Mark N. Lampert | |
| Mark N. Lampert | Mark N. Lampert | |||
| President | President | |||
| BVF INC. | ||||
| BVF PARTNERS L.P. | By: | /s/ Mark N. Lampert | ||
| Mark N. Lampert | ||||
| By: | BVF Inc., its general partner | President | ||
| By: | /s/ Mark N. Lampert | |||
| Mark N. Lampert | /s/ Mark N. Lampert | |||
| President | MARK N. LAMPERT | |||