SAN DIEGODoses of topotecan(Drug information on topotecan) (Hycamtin) one third lower than the label recommends are still effective as ovarian cancer salvage therapy and cause much less hematologic toxicity, Michael Rodriguez, MD, reported at the 31st Annual Meeting of the Society of Gynecologic Oncologists (SGO).
Dr. Rodriguez and his colleagues at Case Western Reserve University compared results with topotecan 1.0 mg/m² to historical data from patients receiving 1.5 mg/m². Both regimens were given for 5 days every 3 weeks to patients with recurrent epithelial ovarian carcinoma after prior treatment with platinum and paclitaxel(Drug information on paclitaxel) (Taxol).
The Case Western study included 23 patients; 65% were refractory and 35% were resistant to paclitaxel/carboplatin (Paraplatin) chemotherapy. Mean age was 64.8 years (range, 40 to 77), and median number of prior chemotherapeutic regimens was 3 (range, 1 to 5). Response was defined as a 50% reduction of tumor on CT or 50% reduction in CA-125 level lasting at least 1 month.
In our study, 6 of 23 patients (26%) responded to chemotherapy vs 19 of 139 patients (13.7%) in the study by Bookman et al [J Clin Oncol 16:3345-3352, 1998], Dr. Rodriguez told ONI.
Patients treated with the lower dose had significantly less grade 3-4 neutropenia and grade 4 leukopenia. These patients also had nonsignificantly lower rates of grade 4 thrombocytopenia and anemia, grade 3 thrombocytopenia, infections associated with neutropenia, and febrile neutropenia (see Table).
The lower topotecan dose is active in platinum- and paclitaxel-resistant or refractory ovarian cancer, and this schedule may permit its wider use, he said. He added that adjustments to permit the use of topotecan in combination regimens should be by lowering the dose, not by changing the schedule.