A phase I clinical trial of intraperitoneal thiotepa for refractory ovarian cancer

Treatment options for patients with ovarian cancer who have failed systemic and intraperitoneal (ip) cisplatin-based chemotherapy are limited. We conducted a phase I clinical study of ip thiotepa in patients with refractory ovarian cancer to determine the maximum tolerated dose (MTD). Ten patients were given 39 courses of thiotepa (median number of courses per patient, 3.5; range, 1-10+). All patients had received prior ip cisplatin; 7 also had received iv cisplatin, and 5 had three or more prior regimens. Thiotepa (30-80 mg/m2) was given ip in 2 liters normal saline every 4 weeks. The therapy was well tolerated. There was no vomiting, stomatitis, alopecia, or peritonitis. The dose-limiting toxicity was myelosuppression. With repeated doses, patients had a delayed marrow recovery and required a 1- to 2-week delay in treatment. Six patients had stable disease (duration 2-14+ months; median duration 5 months); 1 patient had a 50% decrease in CA-125 level, and 1 patient with no measurable disease remained clinically disease-free. In summary, ip thiotepa had clinical activity in heavily pretreated patients with refractory ovarian cancer with disease stabilization seen in 6 of 9 evaluable patients and a partial response seen in 1 patient. Myelosuppression was the only toxicity encountered. A dose of 60 mg/m2 ip is recommended for phase II studies.