Clinical trials with intraperitoneal cisplatin microspheres for malignant ascites--a pilot study.

A new formulation (CDDP-MS), which is composed of lactic acid oligomer microspheres incorporating cisplatin, has been developed in a dosage form for peritoneal carcinomatosis. In this pilot study, CDDP-MS was used clinically for the treatment of malignant ascites induced by cancers of the digestive organs. Thirteen patients with malignant ascites received an i.p. administration of CDDP-MS, of which 12 received 100 mg and one received 200 mg of cisplatin/person to control the ascites. Total platinum levels in ascites and blood plasma were measured periodically. Intraperitoneal CDDP-MS decreased malignant ascites completely in eight patients and partially in four patients, and thus gave a response rate of 92%. The platinum concentration in ascites was maintained at a high level for a week after administration, whereas the concentrations in blood plasma were low. The side effects were well tolerated. Intraperitoneal CDDP-MS exhibits a marked therapeutic benefit with small systemic side effects for the treatment of malignant ascites.