Clinical status and optimal use of topotecan.

Topotecan (Hycamtin) is a promising new topoisomerase I-targeting anticancer agent that first entered clinical trials in 1989 under National Cancer Institute sponsorship in collaboration with SmithKline Beecham. In 1996, it was approved for use by the United States Food and Drug Administration (FDA) for previously treated patients with advanced ovarian cancer. For these patients, topotecan provides another therapeutic option upon disease progression after initial platinum-based chemotherapy. Topotecan also has activity in other tumor types, including small-cell lung cancer, hematologic malignancies and pediatric neuroblastoma and rhabdomyosarcoma. Topotecan combination regimens with paclitaxel (Taxol), etoposide (VePesid), cisplatin (Platinol), and cytarabine and with other treatment modalities, such as radiation therapy, are in development. Studies evaluating topotecan combinations as initial treatment in such diseases as ovarian and small-cell lung carcinoma are also underway. It is hoped that earlier use of topotecan, with its novel mechanism of action, will prolong survival and increase cure rates in patients with these chemoresponsive tumors. Whether or not such hopes are realized, these important studies will help define the role of topotecan in cancer chemotherapy.