VIENNA--For women with advanced epithelial ovarian cancer who fail one
platinum-based regimen, topotecan (Hycamtin) may represent a promising
alternative to 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 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.