VIENNA--For women with advanced epithelial ovarian cancer who fail one platinum-based regimen, topotecan(Drug information on topotecan) (Hycamtin) may represent a promising alternative to paclitaxel(Drug information on paclitaxel) (Taxol), reported W. W. ten Bokkel Huinink, MD, of the Netherlands Cancer Institute.
He spoke at the 21st Congress of the European Society for Medical Oncology (ESMO) on behalf of the International Topotecan Study Group.
Dr. ten Bokkel Huinink and his co-investigators in Europe, the United States, and Canada randomized study enrollees to treatment every 3 weeks with either topotecan, 1.5 mg/m2 as a 30-minute infusion daily for 5 days, or paclitaxel, 175 mg/m2 as a 3-hour infusion. Patients received an average of three to five courses.
The topoisomerase I inhibitor achieved a response rate of 21% with a duration of 26 weeks, compared with 14% and 22 weeks for paclitaxel. These differences failed to reach statistical significance in this 226-patient study. Nonetheless, Dr. ten Bokkel Huinink said, topotecan stretched the time to progression to 19 weeks vs 15 weeks with paclitaxel (P less than .05), and prolonged overall survival to 63 weeks vs 53 weeks with paclitaxel.
The trial also revealed a 13% response rate among women who failed to respond to paclitaxel and were switched to topote-can, and an 8% response rate in topotecan failures after crossover to paclitaxel.
"I'm one of the few investigators to have experience with the combination of cisplatin(Drug information on cisplatin) and paclitaxel, and topotecan is the only drug I know to have some activity in women already pretreated with cisplatin and paclitaxel," Dr. ten Bokkel Huinink commented.
An apparent downside of topotecan therapy was a higher percentage of treatment courses complicated by grade 3 or 4 neutropenia, thrombocytopenia, and anemia. However, the Topotecan Study Group characterized these hematologic toxicities as "reversible, noncumulative, and manageable."
An ongoing US-European trial involving about 400 patients is currently weighing the comparative efficacy of cisplatin-topotecan and cisplatin-paclitaxel as first-line regimens for ovarian cancer.