CUSIP NO. 046513 10 7 13 G Exhibit 99.1

AGREEMENT

Pursuant to Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree that only one statement containing the information required by Schedule 13G need be filed with respect to the ownership by each of the undersigned of Common Stock of AtaraBiotherapeutics, Inc.

Dated: February 13, 2018

DAG VENTURES V-QP, L.P.
BY:	DAG VENTURES MANAGEMENT V, LLC
ITS:	GENERAL PARTNER
By:	/s/ R. Thomas Goodrich
	R. Thomas Goodrich
	Managing Director
DAG VENTURES V, L.P.
BY:	DAG VENTURES MANAGEMENT V, LLC
ITS:	GENERAL PARTNER
By:	/s/ R. Thomas Goodrich
	R. Thomas Goodrich
	Managing Director
DAG VENTURES MANAGEMENT V, LLC
By:	/s/ R. Thomas Goodrich
	R. Thomas Goodrich
	Managing Director
	/s/ R. Thomas Goodrich
R. Thomas Goodrich
	/s/ John J. Cadeddu
John J. Cadeddu