Exhibit 99.1
Joint Filing Agreement
The undersigned hereby agree that the Statement on Schedule 13G dated February 3, 2020 with respect to the shares of Common Stock of AnaptysBio, 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: February 3, 2020
| BIOTECHNOLOGY VALUE FUND, L.P. | Biotechnology Value Trading Fund OS LP | |||
| By: | BVF I GP LLC., its general partner | |||
| By: | BVF Partners L.P., its investment manager | |||
| By: | /s/Mark N. Lampert | By: | BVF Inc., its general partner | |
| Mark N. Lampert | ||||
| Chief Executive Officer | By: | /s/Mark N. Lampert | ||
| Mark N. Lampert | ||||
| President | ||||
| BVF I GP LLC | ||||
| By: | /s/Mark N. Lampert | BVF GP HOLDINGS LLC | ||
| Mark N. Lampert | ||||
| Chief Executive Officer | By: | /s/ Mark N. Lampert | ||
| Mark N. Lampert | ||||
| Chief Executive Officer | ||||
| BIOTECHNOLOGY VALUE FUND II, L.P. | ||||
| By: | BVF II GP LLC its general partner | BVF PARTNERS L.P. | ||
| By: | /s/Mark N. Lampert | By: | BVF Inc., its general partner | |
| Mark N. Lampert | ||||
| Chief Executive Officer | By: | /s/ Mark N. Lampert | ||
| Mark N. Lampert | ||||
| President | ||||
| BVF II GP LLC | ||||
| By: | /s/Mark N. Lampert | BVF INC. | ||
| Mark N. Lampert | ||||
| Chief Executive Officer | By: | /s/ Mark N. Lampert | ||
| Mark N. Lampert | ||||
| President | ||||
| BVF PARTNERS OS LTD. | ||||
| By: | BVF Partners L.P., its sole member | Mark N. Lampert | ||
| By: | BVF Inc., its general partner | MARK N. LAMPERT | ||
| By: | /s/Mark N. Lampert | |||
| Mark N. Lampert | ||||
| President | ||||