Long-term survival in epithelial ovarian cancer remains problematic despite multimodality therapy. A fundamental difficulty is the development of tumor resistance to platinum compounds. Analogs have been developed that demonstrate activity in platinum-resistant cell lines both in vitro and in vivo. Lobaplatin (D-19466), a third-generation compound, demonstrates significant activity in carboplatin and cisplatin-resistant cell lines. Lobaplatin was given to 17 assessable patients with platinum-refractory ovarian cancer. The drug was initially administered at a dose of 50 mg/m2 but was later reduced to 40 mg/m2 because of excessive thrombocytopenia. Nine patients required red cell transfusions during therapy. Cycles were repeated every 21-35 days (median cycle length 28 days). No objective responses were observed. Lobaplatin has no activity in platinum-resistant epithelial ovarian cancer.