UNITED STATES

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 15, 2008

Kosan Biosciences Incorporated

(Exact name of registrant as specified in its charter)

Delaware

(State or other jurisdiction of incorporation)

000-31633	94-3217016
(Commission File Number)	(IRS Employer Identification No.)

3832 Bay Center Place, Hayward, CA 94545

(Address of principal executive offices, including Zip Code)

Registrant’s telephone number, including area code: (510) 732-8400

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ 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))

Item 8.01. Other Events.

On January 15, 2008, Kosan Biosciences Incorporated announced the initiation of a Phase 2 trial of alvespimycin, the company’s second-generation Hsp90 inhibitor, in patients with HER2-positive metastatic breast cancer.

A copy of the press release issued in connection with this announcement is attached as Exhibit 99.1 to this current report and is incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Number	Description
99.1	Press Release of Kosan Biosciences Incorporated, dated January 15, 2008

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.

		KOSAN BIOSCIENCES INCORPORATED
Dated:	January 16, 2008	By:	/s/ Gary S. Titus
			Gary S. Titus
			Senior Vice President and Chief Financial Officer

EXHIBIT INDEX

Number	Description
99.1	Press Release of Kosan Biosciences Incorporated, dated January 15, 2008