KOSAN Biosciences, Inc. Announces Robert G. Johnson, Jr. Resigns as President and Chief Executive Officer

HAYWARD, Calif., Feb. 28 /PRNewswire-FirstCall/ -- Kosan Biosciences Incorporated today announced that Robert G. Johnson, Jr., M.D., Ph.D., has resigned as President and Chief Executive Officer and a member of Kosan’s Board of Directors. Helen S. Kim, who joined Kosan in January 2008 as Senior Vice President and Chief Business Officer, has been appointed President of Kosan.

“Under Robert’s leadership, Kosan made the successful transition from a research-oriented organization to a product development-focused company, and he has made many significant contributions to Kosan over the last eight years,” said Peter Davis, Ph.D., Chairman of Kosan’s Board of Directors. “Robert assumed the chief executive officer role during a period of transition and executed his responsibilities skillfully and energetically. He helped Kosan to manage a period of significant change to emerge as a better-positioned company and to recruit the senior management team that will help lead the company into its next phase. His commitment to Kosan has been intense, and his positive influence has been felt throughout the company. We express our sincerest thanks to Robert and wish him well in his new pursuits.” Dr. Davis also noted: “Our new President, Helen Kim, has broad experience in product development and commercialization, as well as business and corporate development. These talents plus her demonstrated leadership will strengthen Kosan’s ability to advance key product candidates toward the market.”

Kosan also announced that the company has reprioritized its development portfolio. The company’s priorities are to advance development of its lead product candidate, Hsp90 inhibitor tanespimycin, in multiple myeloma and in metastatic breast cancer, and its lead epothilone candidate, KOS-1584, in non-small cell lung cancer, and potentially other indications. Kosan’s development portfolio prioritizes clinical programs and focuses resources on product candidates that it believes represent the highest therapeutic potential and commercial value for the company in the near-term.

“The reprioritization of our clinical portfolio to focus on our lead product candidates, tanespimycin and KOS-1584, strengthens our product focus and enables us to direct resources toward our highest potential value clinical programs,” said Helen S. Kim, Kosan’s President and Chief Business Officer. “We believe that tanespimycin and KOS-1584 are Kosan’s most valuable near-term product opportunities. Tanespimycin is the most advanced Hsp90 inhibitor in clinical development and has the potential to be the first Hsp90 inhibitor to reach the market. We believe that developing KOS-1584 in non-small cell lung cancer, and advancing tanespimycin in breast cancer while we complete our TIME registration program in multiple myeloma, will be major value drivers for Kosan. We plan to continue to review our portfolio strategies with the goal of ensuring effective and efficient use of our resources.”

Tanespimycin in Myeloma Evaluation (TIME) Registration Program on Track

The pivotal Phase 3 TIME-1 trial, the foundation of the tanespimycin registration program in multiple myeloma, is open and enrolling patients. TIME-1 is an open-label, randomized, multi-center, international trial that is designed to enroll approximately 470 patients with first-relapse disease. The TIME clinical program will utilize Kosan’s improved, proprietary, injectable suspension formulation of tanespimycin. TIME-1 is designed with a primary endpoint of progression-free survival (PFS) and is designed to show a 2.75 month PFS benefit in patients treated with tanespimycin plus Velcade(R) (bortezomib) compared to patients treated with bortezomib alone.

Kosan has completed both a Special Protocol Assessment with the U.S. Food and Drug Administration and a Scientific Advice process with the Committee for Medicinal Products for Human Use of the centralized European Medicines Agency.

Kosan’s TIME program is expected to include a second trial to support the pivotal TIME-1 trial with additional safety and efficacy data. Kosan plans to initiate the supporting trial in early 2009 and anticipates that the trial can be completed within the timeframe of TIME-1.

Tanespimycin Breast Cancer Strategy

Kosan intends to advance tanespimycin in metastatic breast cancer. Tanespimycin has demonstrated encouraging, potent antitumor activity and a high level of tolerability in HER2-positive metastatic breast cancer. Data reported from an ongoing Phase 2 trial of tanespimycin plus Herceptin(R) (trastuzumab) showed a 55% clinical benefit in patients who had failed trastuzumab therapy prior to entering the trial, including 5 partial responses in 20 evaluable patients. Updated data from this ongoing Phase 2 trial show several additional partial responses among patients treated with the injectable suspension formulation of tanespimycin, supporting Kosan’s strategy to advance tanespimycin into later-stage trials.

We are finalizing our development strategy to pave the way toward a potential registration clinical program for tanespimycin in breast cancer. Kosan expects to conduct enabling studies considering tanespimycin as monotherapy and in combination with other agents such as Taxol(R) (paclitaxel), Xeloda(R) (capecitabine(R)) and/or Herceptin(R).

Kosan plans to discontinue development of alvespimycin in lieu of development of tanespimycin. The process of ending current alvespimycin clinical trials has been initiated.

KOS-1584 Poised to Begin Phase 2 Lung Cancer Trial

KOS-1584 has the potential to assume a leading role in the emerging epothilone class of anticancer agents. Epothilones are highly potent microtubulin stabilizing compounds with a similar mechanism of action to taxanes and broad applicability in a wide range of tumors. Epothilones are active in both taxane-sensitive and taxane-resistant cancers and have demonstrated low susceptibility to tumor resistance mechanisms. With the recent FDA approval of the first epothilone (BMS’ ixabepilone), the epothilone class has gained clinical and market validation.

KOS-1584 has demonstrated antitumor activity and favorable tolerability in Phase 1 trials in patients with solid tumors, including non-small cell lung, ovarian and pancreatic cancers. Kosan intends to initiate a Phase 2 trial of KOS-1584 in non-small cell lung cancer patients who have received one prior chemotherapy regimen in the first quarter of 2008. Kosan may conduct additional Phase 2 trials of KOS-1584. Kosan believes that KOS-1584 has best-in-class potential based on the compound’s activity and tolerability profile, which may contrast with currently marketed and other development-stage compounds in this class.

Conference Call and Webcast Today

Simultaneous with this announcement of Kosan’s clinical portfolio strategy, Kosan today announced its fourth quarter and full year 2007 financial results. Kosan will hold a conference call and webcast today to discuss both of these announcements. Access information is as follows.

The conference call and webcast are scheduled for today at 1:30 p.m. Pacific / 4:30 p.m. Eastern. To access the live call, please dial 888.713.4213 (US) or 617.213.4865 (international), access code 10071927. Interested parties may listen to the webcast live at http://www.kosan.com by clicking on the “Webcasts” tab under the heading “Investors/Press.” The webcast is also being distributed over Thomson’s Investor Distribution Network to both institutional and individual investors. Individual investors can listen to the call through Thomson’s individual investor center at http://www.earnings.com or by visiting any of the investor sites in Thomson’s Individual Investor Network. Institutional investors can access the call via Thomson’s password-protected event management site, StreetEvents, at http://www.streetevents.com. A telephonic replay will be available through March 6, 2008 by dialing 888.286.8010, access code: 51294639. International callers can dial 617.801.6888, access code: 51294639

About Kosan

Kosan Biosciences is a biotechnology company advancing two new classes of anticancer agents through clinical development -- a Hsp90 (heat shock protein 90) inhibitor and an epothilone. Hsp90 inhibitors have a novel mechanism of action targeting multiple pathways involved in cancer cell growth and survival. Tanespimycin (KOS-953) is being tested in combination with Velcade(R) (bortezomib) in patients with multiple myeloma in a clinical program called TIME. Tanespimycin is also being studied in HER2-positive metastatic breast cancer in combination with Herceptin(R) (trastuzumab). Epothilones inhibit cell division with a mechanism of action similar to taxanes, one of the most successful classes of anti-tumor agents. KOS-1584 is in Phase 1 clinical trials in patients with solid tumors. Kosan’s motilin agonist compound, KOS-2187, licensed to Pfizer, is in a Phase 1 trial in gastroesophageal reflux disease (GERD). For additional information on Kosan Biosciences, please visit the company’s website at http://www.kosan.com.

This press release contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995 (the “Act”). Such forward-looking statements include but are not limited to statements regarding the further development and potential safety, efficacy, regulatory status, commercial potential and other characteristics of Kosan’s product candidates; the continuation of current clinical trials; the initiation of additional clinical trials and the timing thereof and the use of Kosan’s financial resources. Words such as “will,” “expect,” “believe,” “may,” “intend,” “plan,” “potential” and similar expressions are intended to identify forward-looking statements. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. These forward-looking statements are based upon Kosan’s current expectations. Forward-looking statements involve risks and uncertainties. Kosan’s actual results and the timing of events could differ materially from those anticipated in such forward-looking statements as a result of these risks and uncertainties, which include, without limitation, risks related to the uncertain progress and results of Kosan’s preclinical and clinical testing, including the risks that studies and trials may not demonstrate safety and efficacy sufficient to initiate clinical trials on the timing currently anticipated, or at all, continue clinical development, obtain the requisite regulatory approvals or result in a marketable product; the conduct of clinical trials; manufacturing; regulatory approval requirements and process; the effort and expense necessary for further development of Kosan’s product candidates, including the costs of bortezomib; intellectual property matters, including Kosan’s ability to obtain valid and enforceable patents covering its product candidates; Kosan’s dependence on its collaboration with Pfizer for development of its motilin agonist product candidate; Kosan’s need for additional financing and Kosan’s strategy to enter into partnering or licensing arrangements. These and other risk factors are discussed under “Risk Factors” in Kosan’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2007 and other periodic filings with the SEC. Kosan expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein.

Velcade(R) (bortezomib) is a registered trademark of Millennium Pharmaceuticals, Inc.

Herceptin(R) (trastuzumab) is a registered trademark of Genentech, Inc.

Taxol(R) (paclitaxel) is a registered trademark of Bristol-Myers Squibb Company

Xeloda(R) (capecitabine) is a registered trademark of Hoffman-La Roche, Inc.

CONTACT: Helen S. Kim, President and Chief Business Officer,
+1-510-731-5270, mobile, +1-510-853-1314, kim@kosan.com, or Jane Green, VP,
Corporate Communications, +1-510-731-5335, mobile, +1-415-652-4819,
green@kosan.com, both of Kosan Biosciences Incorporated

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

MORE ON THIS TOPIC