Purpose: Most ovarian cancers recur after first-line treatment. We studied the pharmacology, tolerability, and therapeutic potential of intraperitoneal (IP) topotecan, alone and with IP cisplatin.
Methods: Patients received IP topotecan 1.5 mg (flat dose) daily on days 1-5 (level 0) via IP catheter. Subsequent cohorts received IP cisplatin 50 mg/m(2) on day 1 added to topotecan 1.5 mg on days 1-3 (level I), topotecan 1.25 mg on days 1-3 (level II), or topotecan 1.25 mg on days 1-5 (level III). Plasma and IP concentrations of total and lactone (E-ring closed) topotecan were measured on days 1 and 2 in cycles 1 and 2.
Results: Sixteen patients (15 tubo-ovarian, 1 gastric cancers) were entered at levels 0 (3), I (4), II (4), or III (5). Dose-limiting neutropenias occurred in seven patients at dose levels I and III; grade 3 thrombocytopenia occurred in two at level III. Other toxicities included grade 1 hives in two, serum creatinine elevations in two, and Staphylococcus epidermidis and chemical peritonitis (one each). A median progression-free survival of 13 months was recorded among ovarian cancer patients who had minimal (6) or no residuum (3) after platinum-based induction; 5 are alive at 4 years. Topotecan's AUC IP/AUC plasma ratios ranged from 13 to 119.
Conclusion: Topotecan IP for 3-5 days is tolerable; occasionally, myelosuppression is dose-limiting. Topotecan 1.25 mg (days 1-3) with IP cisplatin 50 mg/m(2) (day 1) is a regimen suitable for consolidation in phase 3 trials.