(State or other jurisdiction

of incorporation)

(Commission

File Number)

(IRS Employer

Identification Number)

Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year

authorize 300,000,000 shares of common stock;

delete all references to the various series of preferred stock that were previously authorized and instead create 10,000,000 shares of undesignated preferred stock with terms to be set by the board of directors, which rights could be senior to those of the common stock;

do not provide for cumulative voting in the election of directors, which would otherwise allow less than a majority of stockholders to elect director candidates;

require the advance notice of nominations for election to the board of directors or for proposing matters that can be acted upon at a stockholders’ meeting;

allow the board of directors to alter the bylaws without obtaining stockholder approval;

eliminate the rights of stockholders to call a special meeting of stockholders and to take action by written consent in lieu of a meeting;

require the approval of at least 66 2/3% of the shares entitled to vote to remove a director for cause;

require the approval of at least 66 2/3% of the shares entitled to vote to adopt, amend or repeal the bylaws or repeal the provisions of the amended and restated certificate of incorporation regarding the election and removal of directors;

designate the Court of Chancery of the State of Delaware to be the sole and exclusive forum for any derivative action or proceeding brought on the Company’s behalf, any action asserting a breach of fiduciary duty, any action asserting a claim against the Company arising pursuant to the General Corporation Law of the State of Delaware, the Certificate of Incorporation or Bylaws, any action to interpret, apply, enforce, or determine the validity of the Certificate of Incorporation or Bylaws, or any action asserting a claim against the Company that is governed by the internal affairs doctrine, unless the Company consents in writing to the selection of an alternative forum;

designate the U.S. federal district courts as the exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act of 1933, as amended, unless the Company consents in writing to the selection of an alternative forum; and

establish a classified board of directors, as a result of which the successors to the directors whose terms have expired will be elected to serve from the time of election and qualification until the third annual meeting following their election.

Other Events.

Financial Statements and Exhibits.

Exhibit No.

Description

GRITSTONE ONCOLOGY, INC.

Jean-Marc Bellemin

Executive Vice President, Chief Financial Officer