SAN ANTONIO, Dec. 8 /PRNewswire-FirstCall/ -- Kosan Biosciences Incorporated today announced interim results of an ongoing Phase II clinical trial indicating that KOS-862 administered as a monotherapy has demonstrated anti-tumor activity in patients with anthracycline and taxane pretreated metastatic breast cancer. KOS-862 is a polyketide that inhibits cancer cells by the same mechanism as paclitaxel. Interim results were presented today at the 28th Annual San Antonio Breast Cancer Symposium.
The poster presentation #1087 "A Phase II Study of KOS-862 (Epothilone D) in Anthracycline and Taxane Pretreated Metastatic Breast Cancer: Updated Results" included preliminary efficacy results from 41 evaluable patients in the Phase II clinical trial, all of whom had advanced metastatic disease and had previously failed treatment with anthracycline and taxane. Twelve percent of the evaluable patients (five patients) treated with KOS-862 had confirmed partial responses (PR), including two patients with hepatic (liver) metastases who exhibited a greater than 50 percent tumor reduction according to RECIST (Response Evaluation Criteria In Solid Tumors). The median duration of response for the five PR patients was 10.1 weeks. An additional three patients (7.3% of the evaluable patients) had stable disease greater than four cycles. Three of five confirmed PR patients had adjuvant taxane therapy; four of five had received prior taxane therapy for metastatic disease.
"The interim Phase II results of KOS-862 as a monotherapy treatment for metastatic breast cancer reveal encouraging anti-tumor activity in patients previously treated with anthracyclines and taxanes," said Daniel V. Santi, M.D., Ph.D., Kosan Chairman and Chief Executive Officer. "We continue to accrue patients in this study and look forward to the presentation of full data upon trial completion."
In the Phase II clinical trial, KOS-862 was administered by 90 minute intravenous infusion weekly for three weeks every four weeks at a dose of 100 mg/m2. No grade 4 adverse events were observed. Neurotoxicities were the most common safety events related to KOS-862 therapy with peripheral neuropathy the most common neurotoxicity; the Grade 3 incidence was less than 12%. A Phase Ib/II combination study of weekly KOS-862 and weekly Herceptin(R) in patients with HER-2 overexpressing metastatic breast cancer is ongoing.
About KOS-862
KOS-862 (Epothilone D) is a polyketide that inhibits cancer cell growth in vitro by a mechanism similar to paclitaxel, and preclinical models have shown the compound to be effective against paclitaxel-resistant tumors. In addition to the Phase II monotherapy trial in breast cancer, KOS-862 continues to be evaluated in a Phase I/II combination trial with Herceptin(R).
Roche and Kosan initiated a global development and commercialization agreement for KOS-862 and other compounds in the epothilone class in September 2002. According to the agreement, Roche has the worldwide exclusive right to market and sell KOS-862, KOS-1584, a second epothilone drug candidate currently in Phase I clinical trials, and other epothilone analogs owned by or licensed to Kosan for the treatment of cancer; Kosan will co-develop and has the right to co-promote Kosan/Roche epothilone products in the U.S. for the treatment of cancer.
About Kosan
Kosan Biosciences is advancing two new classes of anticancer agents through clinical development. Kosan's most advanced compound, KOS-862 (Epothilone D), is in Phase II and Phase Ib clinical trials in breast cancer, and a second epothilone drug candidate, KOS-1584, is in Phase I clinical trials. These programs are partnered with Roche through a global development and commercialization agreement. Kosan is also developing Hsp90 (heat shock protein 90) inhibitors, in collaboration with the National Cancer Institute (NCI), including 17-AAG, a first generation geldanamycin analog. Kosan's proprietary formulation of 17-AAG, KOS-953, is in Phase I and Phase Ib clinical trials for multiple myeloma and metastatic breast cancer. In addition, a second-generation geldanamycin analog, KOS-1022 (DMAG), is currently in Phase I clinical trials, in collaboration with the NCI. Kosan has generated a pipeline of additional product candidates for gastrointestinal motility, infectious diseases and cancer 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 www.kosan.com.
This press release contains "forward-looking" statements, including statements relating to ongoing and further development of KOS-862 in the treatment of cancer. Any statements contained in this press release that are not statements of historical fact may be deemed to be forward-looking statements. There are a number of important factors that could cause the results of Kosan to differ materially from those indicated by these forward- looking statements, including, among others, risks related to the clinical advancement of KOS-862 and KOS-1584, including the risk that clinical trials for this product candidate may not demonstrate safety and efficacy sufficient to obtain the requisite regulatory approvals or to result in a marketable product, risks related to Kosan's dependence on its collaboration with Roche for the development of KOS-862 and KOS-1584, risks related to the possible determination that an earlier-stage compound, such as KOS-1584, will be more appropriate for commercial development than KOS-862 and other risks detailed from time to time in the Company's SEC reports, including its Quarterly Report on Form 10-Q for the quarter ended September 30, 2005 and other periodic filings with the SEC. Kosan does not undertake any obligation to update forward-looking statements.
NOTE: Herceptin(R) is a registered trademark of Genentech, Inc.
Kosan Biosciences IncorporatedCONTACT: 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/
