It also showed signs of activity in patients with non-small cell lung, ovarian, breast, prostate, pancreatic, head and neck and colon cancer, according to Kosan. The Phase I trial explored two different schedules of epothilone drug, KOS-1584/R1645 using escalating doses. Epothilones inhibit cell division with a mechanism of action similar to taxanes, one of the most successful classes of anti-tumor agents.
Trial results included: one confirmed partial response in a patient with advanced non-small cell lung cancer, with 44% tumor shrinkage; and one patient with breast cancer experienced a 40% reduction in tumor marker CA-15.3, 42.5% reduction in CA27,29 and 30% reduction in CEA.
One patient with advanced ovarian cancer had 40% tumor marker CA125 decrease and 20% shrinkage of nodal disease; one patient with advanced prostate cancer had 94% reduction in PSA and improved nodal disease; one patient with pancreatic cancer had a 39% decrease in CA19-9; and six patients had stable disease.
Common drug-related toxicities varied depending on dose and dose schedule, and were predominantly gastrointestinal symptoms, primarily diarrhea, that were generally manageable with supportive care.
Robert Johnson Jr, Kosan’s president and CEO, said: “We believe that KOS-1584 has the potential to achieve best-in-class status in the emerging epothilone market as well as to compete in the established taxane market. We look forward to our planned commencement of a Phase II clinical program for KOS-1584 toward the end of 2007.”