EXHIBIT A
JOINT FILING AGREEMENT
In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned agree to the joint filing on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the Common Stock of Portola Pharmaceuticals, Inc. and further agree that this agreement be included as an exhibit to such filing. Each party to the agreement expressly authorizes each other party to file on its behalf any and all amendments to such statement. Each party to this agreement agrees that this joint filing agreement may be signed in counterparts.
In evidence whereof, the undersigned have caused this Agreement to be executed on their behalf this 4th day of February, 2015.
| MPM BIOVENTURES III, L.P. | MPM BIOVENTURES III-QP, L.P. | |||||
| By: | MPM BioVentures III GP, L.P., | By: | MPM BioVentures III GP, L.P., | |||
| its General Partner | its General Partner | |||||
| By: | MPM BioVentures III LLC, | By: | MPM BioVentures III LLC, | |||
| its General Partner | its General Partner | |||||
| By: | /s/ Luke Evnin |
By: | /s/ Luke Evnin | |||
| Name: Luke Evnin | Name: Luke Evnin | |||||
| Title: Series A Member | Title: Series A Member | |||||
| MPM BIOVENTURES III PARALLEL FUND, L.P. | MPM BIOVENTURES III GMBH & CO. BETEILIGUNGS KG | |||||
| By: | MPM BioVentures III GP, L.P., | By: | MPM BioVentures III GP, L.P., | |||
| its General Partner | in its capacity as the Managing Limited Partner | |||||
| By: | MPM BioVentures III LLC, | By: | MPM BioVentures III LLC, | |||
| its General Partner | its General Partner | |||||
| By: | /s/ Luke Evnin |
By: | /s/ Luke Evnin | |||
| Name: Luke Evnin | Name: Luke Evnin | |||||
| Title: Series A Member | Title: Series A Member | |||||
| MPM ASSET MANAGEMENT INVESTORS 2003 BVIII LLC | ||||||
| By: | /s/ Luke Evnin |
|||||
| Name: Luke Evnin | ||||||
| Title: Manager | ||||||
| MPM BIOVENTURES III GP, L.P. | MPM BIOVENTURES III LLC | |||||
| By: | MPM BioVentures III LLC, | By: | /s/ Luke Evnin | |||
| its General Partner | Name: | Luke Evnin | ||||
| Title: | Series A Member | |||||
| By: | /s/ Luke Evnin |
|||||
| Name: | Luke Evnin | |||||
| Title: | Series A Member | |||||
| By: | /s/ Luke Evnin |
By: | /s/ Ansbert Gadicke | |||
| Name: Luke Evnin | Name: Ansbert Gadicke | |||||
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| By: | /s/ Nicholas Galakatos |
By: | /s/ Michael Steinmetz | |||
| Name: Nicholas Galakatos | Name: Michael Steinmetz | |||||
| By: | /s/ Kurt Wheeler |
By: | /s/ Nicholas Simon III | |||
| Name: Kurt Wheeler | Name: Nicholas Simon III | |||||
| By: | /s/ Dennis Henner |
|||||
| Name: Dennis Henner | ||||||
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