HAYWARD, Calif., April 14 Kosan BiosciencesIncorporated (Nasdaq: KOSN) today announced that the Phase 2 trial ofepothilone KOS-1584 in patients with non-small cell lung cancer has beeninitiated. The Phase 2 trial is an open-label, multi-center, monotherapy studyof KOS-1584 in patients with measurable advanced or metastatic non-small celllung cancer who have previously received only one prior chemotherapy regimen.The primary endpoint of the Phase 2 trial is objective response rate.Secondary endpoints include progression-free survival, time to progression,time to treatment failure, time to response, duration of response and overallsurvival. KOS-1584 will be administered via a 3-hour intravenous infusionweekly for two weeks out of every three weeks at a dose of 25 mg/m(2). ThePhase 2 trial will enroll up to 50 patients in a two-stage Simon design.
"We have been impressed by the breadth and level of activity andtolerability we have observed with KOS-1584 in our Phase 1 trials and believethat KOS-1584 has competitive potential in the emerging epothilone class ofanticancer agents," said Helen S. Kim, Kosan's President and Chief ExecutiveOfficer. "Kosan's epothilone strategy is to advance KOS-1584 to its nextinflection point while seeking a corporate partner to conduct a registrationprogram and advance our preclinical product candidate, KOS-1803, into clinicaldevelopment. We believe that KOS-1584's therapeutic profile and potential fornear-term commercialization enhance its value for potential pharmaceuticalcollaborators."
KOS-1584 is a member of a class of cytotoxic macrolides (epothilones)capable of causing mitotic arrest by polymerization of cellular microtubules.Since microtubules are essential for mitosis, motility, secretion andproliferation, the observed antitumor effects of epothilones have beenattributed to their ability to initiate cell death by inhibiting suchprocesses. KOS-1584 has demonstrated in vitro cytotoxicity, more potent orequipotent to that of Taxol(R) (paclitaxel) in a panel of human cell lines.KOS-1584 has shown significant antitumor activity in a range of xenograftmodels, including non-small cell lung cancer models resistant to paclitaxeland those expressing multidrug resistance. A long eliminationhalf-life was seen in Phase I trials. KOS-1584 has demonstrated antitumoractivity and favorable tolerability in Phase 1 trials in patients with solidtumors, including substantial tumor shrinkage measured by objective responsesin non-small cell lung, ovarian and pancreatic cancers, as well as durablestable disease in many additional tumors.
Kosan Biosciences is a biotechnology company advancing two new classes ofanticancer agents through clinical development -- a Hsp90 (heat shock protein90) inhibitor and an epothilone. Hsp90 inhibitors have a novel mechanism ofaction targeting multiple pathways involved in cancer cell growth andsurvival. Tanespimycin (KOS-953) is being tested in combination withVelcade(R) (bortezomib) in patients with multiple myeloma in a clinicalprogram called TIME. Tanespimycin is also being studied in HER2-positivemetastatic breast cancer in combination with Herceptin(R) (trastuzumab).Epothilones inhibit cell division with a mechanism of action similar totaxanes, one of the most successful classes of anti-tumor agents. KOS-1584 isin a Phase 2 clinical trial in patients with non-small cell lung cancer.Kosan's motilin agonist compound, KOS-2187, licensed to Pfizer for developmentin gastroesophagel reflux disease, is in a Phase 1 trial. For additionalinformation on Kosan Biosciences, please visit the company's website athttp://www.kosan.com.
This press release contains forward-looking statements within the meaningof the "safe harbor" provisions of the Private Securities Litigation ReformAct of 1995 (the "Act"). Such forward-looking statements include but are notlimited to statements rega