CELL THERAPEUTICS REPORTS DATA ON XYOTAX IN PROSTATE CANCER

Cell Therapeutics has announced preliminary results from an investigator-sponsored Phase II study of Xyotax (paclitaxel poliglumex) in patients with androgen-independent prostate cancer, the majority of whom had failed prior treatment with taxane chemotherapy. The results demonstrated a major response rate of 24 percent, with a median overall survival at follow-up of 8.5 months and a median time to progression of 3.5 months.

Of the 24 patients on the study, 80 percent had received prior chemotherapy and 84 percent of those patients were resistant or refractory to prior taxane chemotherapy. Patients treated every three weeks experienced more grade 3 or 4 toxicities than those patients treated every four weeks. No grade 4 neuropathy was seen in either or those dosing schedules, and only one case of grade 4 neutropenia was seen in the monthly dosing schedule.

The median age of patients on the study is 68, with 83 percent of patients having a Gleason score of 7 to 10, which is a poor prognostic factor. The study continues to enroll and follow patients, and the protocol has been amended to include the use of estrogel with Xyotax to determine safety and if efficacy is enhanced.

As previously reported, preclinical data show that in estradiol-supplemented female mice, Xyotax demonstrated a nearly two-fold increase in antitumor activity compared with non-supplemented animals in a colon cancer tumor model. Also, in previous Phase III clinical trials in lung cancer, Xyotax demonstrated the greatest survival advantage in women with normal estrogen levels.

Xyotax is a biologically enhanced chemotherapeutic that links paclitaxel, the active ingredient in Taxol, to a biodegradable polyglutamate polymer, which results in a new chemical entity.