A phase I and pharmacologic study of belotecan in combination with cisplatin in patients with previously untreated extensive-stage disease small cell lung cancer

Abstract

18053 Background: Belotecan (CKD602) is a novel camptothecin derivative antitumor agent. This phase I study was designed to determine the maximum-tolerated dose (MTD), toxicity profile, and dose-limiting toxicity (DLT) of belotecan in combination with cisplatin in patients with previously untreated extensive-stage disease small-cell lung cancer (ED SCLC). Furthermore, pharmacokinetics (PK) and preliminary antitumor activity of belotecan against SCLC were evaluated. Methods: Patients with ED SCLC, age 18–70, ECOG PS 0–2, no prior chemotherapy and adequate organ function were eligible. Cisplatin with fixed dose of 60 mg/m2 was administered intravenously (i.v.) over 2 hours on day 1. Belotecan was administered iv as intermittent 30-minute infusions on days 1 to 4, starting dose of 0.40 mg/m2/day with increment of 0.05 mg/m2/day. Modified Fibonacci escalation was used (3 to 6 patients per cohort) and intra-patient dose escalation was not allowed. PK of belotecan was determined during the first treatment using non-compartmental pharmacokinetic analysis. Results: Seventeen patients were treated at 4 dose levels (0.40 to 0.55 mg/m2/day). At 0.55 mg/m2/day of belotecan, the DLT of grade 4 neutropenia with fever occurred in 2 of 5 patients, and therefore the MTD was 0.50 mg/m2/day. Interestingly, out of 17 patients, there were 14 partial responses (82.4%; 95% CI, 63.4% to 100.0%). PK analysis revealed that at 0.50 mg/m2/day, plasma clearance of belotecan was 5.78 ± 1.32 L/hr and terminal half-life was 8.55 ± 2.12 hr. Fraction of excreted amount in urine was 37.36 ± 5.55 %. PK of belotecan were not altered by administration of cisplatin, as compared with historical control. Conclusions: The MTD of belotecan was 0.50 mg/m2/day for intermittent 30-min i.v. infusion for 4 days in combination with cisplatin 60 mg/m2 on day 1 every 3 weeks. Furthermore, very promising antitumor activity against SCLC was observed. The phase II study is being conducted now. No significant financial relationships to disclose.