KOSAN Biosciences, Inc. To Present At November Healthcare Conferences

HAYWARD, Calif., Nov. 1 /PRNewswire-FirstCall/ -- Kosan Biosciences today announced that Robert G. Johnson, Jr., M.D., Ph.D., Executive Vice President, Development and Chief Medical Officer will present at the Rodman & Renshaw Techvest 7th Annual Healthcare Conference at the New York Palace, New York on Monday, November 7, 2005 at 10:30 a.m. Eastern Time, as well as at the CIBC World Markets Sixteenth Annual Healthcare Conference at the Waldorf-Astoria, New York on Tuesday, November 8, 2005 at 9:30 a.m. Eastern Time.

In addition, management will present at the 6th Annual Global Healthcare Conference at the Hilton Diagonal Mar, Barcelona, Spain on Thursday, November 10, 2005 at 8:00 a.m. local time, and at the 2005 Credit Suisse First Boston Healthcare Conference at the Arizona Biltmore Resort, in Phoenix, Arizona on November 16, 2005 at 3:30 p.m. MST.

Interested parties may access a live webcast of the presentations by visiting the Calendar of Events page under News and Events on Kosan's website at http://www.kosan.com .

It is recommended that listeners log on 15 minutes early in order to register and download any necessary software. If you are unable to participate during the live webcast, a recorded replay of the presentation will be available one hour after the presentation is completed for two weeks.

About Kosan

Kosan Biosciences has two first-in-class anticancer agents in Phase II and Phase Ib clinical trials: KOS-862 (Epothilone D) and 17-AAG, a geldanamycin analog and Hsp90 inhibitor. KOS-862, the Company's lead drug candidate, has a mechanism of action similar to taxanes and is partnered with Roche in a global development and commercialization agreement, along with a follow-on compound, KOS-1584, currently in Phase I testing. 17-AAG targets multiple pathways required for tumor growth and is being developed in collaboration with the National Cancer Institute, in addition to a second-generation geldanamycin analog, KOS-1022 (DMAG), now in Phase I trials. Kosan's proprietary formulation of 17-AAG, KOS-953, is in Phase I and Phase Ib trials. Kosan has generated a pipeline of potentially significant product candidates for cancer, infectious disease and other therapeutic areas based on its proprietary technologies for discovering, developing and manufacturing polyketide analogs. Polyketides are an important class of natural products that have yielded numerous pharmaceuticals for the treatment of cancer, infectious diseases, high cholesterol, transplant rejection and other diseases. For additional information on Kosan Biosciences, please visit the Company's website at http://www.kosan.com .

CONTACT: Susan M. Kanaya, Chief Financial Officer of Kosan Biosciences,+1-510-732-8400, ext. 5227, or kanaya@kosan.com

Web site: http://www.kosan.com/