Effect of topotecan on serum CA-125 in patients with advanced epithelial ovarian cancer

The effect of topotecan on CA-125 serum levels was evaluated in 30 patients with advanced epithelial ovarian cancer. All patients had progressive disease and were relapsing during (11 patients) or after (19 patients) chemotherapy containing paclitaxel and platinum. Topotecan (1.0 mg/m(2)/day) was administered intravenously on Days 1-5 every 3 weeks. The patients had received a median of 2 (1-5) prior regimens. Four patients had increased CA-125 only, and 26 had both measurable disease and increased CA-125. Two patients (7%) achieved a clinical partial response with durations of 5 and 10+ months, respectively. Eighteen other patients (60%) exhibited no clinical change with a median duration of 5+ months (range: 2-11+ months). Among these patients 9 (30%) had a biochemical response. The rate of change in CA-125 (s, slope of the exponential regression curve) during treatment with topotecan was compared with s over a period before treatment. A decrease in s was observed in 20 patients (74%). Comparing the mean values of s before and during topotecan, a significant (P = 0.005) decrease was seen in the CA-125 serum levels. The mean doubling times before and during treatment were 59 and 1421 days, respectively. Toxicity was mainly hematologic. Neutropenia grades III and IV were seen in 16 and 10 patients, respectively. No patients died due to side effects. Generally the side effects were mild to moderate. In conclusion, at the given dose intensity topotecan shows activity in advanced paclitaxel- and platinum-resistant ovarian cancer based on CA-125 measurements.