8-K

QuickLinks -- Click here to rapidly navigate through this document

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 8-K

CURRENT REPORT
Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): January 9, 2002

TULARIK INC.
(Exact name of registrant as specified in its charter)

Delaware
(State of jurisdiction) 000-28347
(Commission File No.) 94-3148800
(IRS Employer Identification No.)

Two Corporate Drive, South San Francisco, CA 94080
(Address of principal executive offices and zip code)

(650) 825-7000
Registrant's telephone number, including area code:

Item 5. Other Events

    On January 9, 2002, Tularik announced the sale of 100,036 shares of its common stock to Medarex, Inc. at $49.982 per share and pursuant to the terms of the Stock Purchase Agreement, dated January 9, 2002, by and between Tularik Inc. and Medarex, Inc. The shares of common stock were registered under Tularik's Form S-3 shelf registration statement.

Item 7. Financial Statements, Pro Forma Financial Information and Exhibits

(c)

Exhibits

Number	Description
5.1	Opinion of Cooley Godward LLP.
23.1	Consent of Cooley Godward LLP. Reference is made to Exhibit 5.1.

SIGNATURES

    Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	TULARIK INC.
Dated: January 9, 2002	By:	/s/ David V. Goeddel David V. Goeddel Chief Executive Officer

EXHIBIT INDEX

Number	Description
5.1	Opinion of Cooley Godward LLP.
23.1	Consent of Cooley Godward LLP. Reference is made to Exhibit 5.1.

QuickLinks

Item 5. Other Events
Item 7. Financial Statements, Pro Forma Financial Information and Exhibits

SIGNATURES
EXHIBIT INDEX

EX-5.1

QuickLinks -- Click here to rapidly navigate through this document

Exhibit 5.1

[COOLEY GODWARD LLP LETTERHEAD]

January 9, 2002

Tularik Inc.
Two Corporate Drive
South San Francisco, CA 94080

Ladies and Gentlemen:

You have request our opinion with respect to certain matters in connection with the sale by Tularik Inc., a Delaware corporation (the "Company"), to Medarex, Inc. of 100,036 shares of the Company's Common Stock with a par value of $0.001 (the "Shares") pursuant to a Registration Statement on Form S-3 and the related Prospectus and Prospectus Supplement filed with the Securities and Exchange Commission (the "Commission"). All of the Shares are to be sold by the Company as described in the Registration Statement and related Prospectus and Prospectus Supplement.

In connection with this opinion, we have examined and relied upon the Registration Statement and related Prospectus and Prospectus Supplement included therein, the Company's amended and restated certificate of incorporation and bylaws, and the originals or copies certified to our satisfaction of such records, documents, certificates, memoranda and other instruments as in our judgment are necessary or appropriate to enable us to render the opinion expressed below. We have assumed the genuineness and authenticity of all documents submitted to us as originals, and the conformity to originals of all documents where due execution and delivery are a prerequisite to the effectiveness thereof.

On the basis of the foregoing, and in reliance thereon, we are of the opinion that the Shares, when sold in accordance with the Registration Statement and related Prospectus and Prospectus Supplement, will be validly issued, fully paid and nonassessable.

We consent to the reference to our firm under the caption "Legal Matters" in the Prospectus and Prospectus Supplement included in the Registration Statement and to the filing of this opinion as an exhibit to the Registration Statement.

Very truly yours,

COOLEY GODWARD LLP

By: /s/ Suzanne Sawochka Hooper Suzanne Sawochka Hooper

QuickLinks

Exhibit 5.1