Exhibit 23.1
CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We consent to the incorporation by reference in this Registration Statement on FormS-8 of our report relating to the financial statements of Sierra Oncology, Inc. and subsidiaries dated February 27, 2018, appearing in the Annual Report on Form10-K of Sierra Oncology, Inc. and subsidiaries for the year ended December 31, 2017.
/s/ Deloitte & Touche LLP
Grand Rapids, MI
November 8, 2018