Phase I clinical and pharmacological study of liposome-entrapped NDDP administered intrapleurally in patients with malignant pleural effusions.

cis-Bis-neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum(II) (NDDP) is a lipophilic non-cross-resistant platinum compound formulated in large multilamellar liposomes (1-3 micrometer). The maximum tolerated dose (MTD) of liposomal-entrapped NDDP (L-NDDP) administered i.v. in humans is 300 mg/m2, and myelosuppresion is the dose-limiting toxicity. L-NDDP administered i.p. is absorbed slowly from the peritoneal cavity of rats. Recently, i.p. cisplatin has been shown to be superior to i.v. cisplatin in improving the survival of patients with ovarian carcinoma and minimal residual disease. We conducted a Phase I study to determine the MTD, side effects, kinetics of absorption into the systemic circulation, and preliminary antitumor activity of L-NDDP administered intrapleurally in patients with free-flowing malignant pleural effusions. Twenty-one patients were treated with escalating doses of L-NDDP by intrapleural administration over 30 min every 21 days. Fourteen patients had adenocarcinoma of the lung, 5 patients had malignant pleural mesothelioma (MPM), and 2 patients had ovarian carcinoma. The dose-limiting toxicity of L-NDDP was chest pain secondary to chemical pleuritis, which was severe in three of four patients treated at 550 mg/m2. The MTD was 450 mg/m2. At this dose, the only toxicity observed was grade 1-2 nausea and vomiting presenting 6-8 h after drug administration. Neither myelosuppression nor nephrotoxicity was observed. Loculation of residual pleural fluid with continued decrease over a period of weeks to months was observed in seven patients; in one of these patients (MPM), the pleural effusion disappeared without evidence of recurrence for 19 + months, and in six patients (three adenocarcinoma of the lung, two MPM, and one ovarian carcinoma), the pleural effusion was reduced by >50% for 5+, 10+, 18+, 8, 5+, and 2+ months. Plasma pharmacokinetic studies showed that the absorption of L-NDDP from the pleural cavity was rapid during the first 2 h, with levels becoming steady (bioavailable or free platinum) or increasing slowly (total plasma platinum) between 6 and 24 h after administration. Urinary excretion was negligible (1-3%). We conclude that: (a) the MTD of intrapleural L-NDDP is 50% higher than the MTD after i.v. administration; (b) intrapleural L-NDDP causes mild nausea and vomiting and no myelosuppression at the MTD; and (c) the absorption of L-NDDP into the systemic circulation is much slower than that of the parent compound cisplatin. Because of the favorable depot effect, lack of systemic toxicity, and control of the pleural effusion in three of five patients with MPM, a disease similar to ovarian carcinoma in that it tends to remain confined to a body cavity, a Phase II study of intrapleural L-NDDP administered in patients with MPM is in progress.