Topotecan: Significant Activity in Ovarian Cancer

ASCO--Topotecan (Hycamtin), an inhibitor of topoisomerase I, significantlyincreased time to disease progression--23 weeks vs 14 weeks forpaclitaxel (Taxol)--when used as second-line therapy in womenwith recurrent ovarian cancer, James Carmichael, MD, of the Universityof Nottingham, said at an ASCO scientific session.

Topotecan was well tolerated by most patients, he said, but "myelosuppressionoccurred in a high proportion of patients and was severe in anumber of them." He called the problem "predictableand manageable with the use of growth factors or modest dose reductions."

The phase III multinational trial, sponsored by SmithKline Beecham,randomized 235 patients who had received one prior platinum-containingregimen.

Many patients did not show a response to topotecan until theyhad received three courses or more, he said, "so it is importantto continue treatment to achieve the maximum response rate."

Among the paclitaxel failures, 53 patients were crossed over totopotecan, and five partial responses were seen. "I thinkthis is important that we are seeing responses both in platinumand paclitaxel failures," Dr. Carmichael said.

The discussant, David S. Alberts, MD, of the University of Arizona,called topo-tecan an important new agent, but pointed out thatin this study, it was compared to what may be an inferior paclitaxelregimen, ie, 3-hour vs 24-hour infusion.