Roche and Kosan Breast Cancer Phase II Trial to Proceed

April 5, 2005

Kosan Biosciences has announced that its Phase II clinical trial of KOS-862 (Epothilone D) as monotherapy for patients with metastatic breast cancer will proceed to full enrollment of the study following the successful completion of the interim analysis.

The multicenter Phase II study is being conducted according to a two-stage Simon trial design in which the primary objective must be met in the first stage of the trial before proceeding to the second stage. KOS-862 is a polyketide that inhibits cancer cells by the same mechanism as paclitaxel, and preclinical models have shown the compound to be effective against paclitaxel-resistant tumors.

In addition to the Phase II monotherapy trials in breast and prostate cancer, Roche and Kosan are evaluating KOS-862 in three ongoing Phase Ib combination studies with Gemzar, Paraplatin and Herceptin.