Secondary response of ovarian tumors to topotecan treatment

ZD0473 combined with other chemotherapeutic agents for the treatment of solid malignancies

Platinum-based combination chemotherapy regimens are the mainstay of current treatments for advanced solid malignancies. Preclinical in vitro studies have shown synergism with ZD0473 in combination with several agents, including vinorelbine and topotecan. This paper reviews the tolerability and activity observed with ZD0473 in combination with vinorelbine or topotecan, in two Phase I dose-escalating studies in patients with advanced, solid, refractory malignancies. Twenty-four patients were included in the ZD0473 plus vinorelbine trial and were treated with doses of ZD0473 60-150 mg/m2 and vinorelbine 15-25 mg/m2. In this trial, dose-limiting toxicity comprised non-haematological events and the most common grade 3/4 toxicities included neutropenia (54.2%), thrombocytopenia (29.2%) and anaemia (20.8%). Eleven patients were included in the ZD0473 plus topotecan trial and were treated with ZD0473 60-90 mg/m2 and topotecan 0.5 mg/m2/day for 3 or 5 days. In this trial, dose-limiting toxicity comprised haematological events and the most common grade 3/4 toxicities included thrombocytopenia (63.6%), neutropenia (36.4%) and anaemia (18.2%). No objective responses were observed in either trial, but disease stabilisation occurred in 29.2% and 27.3% of patients in the vinorelbine and topotecan trials, respectively.

Topotecan has substantial antitumor activity as first-line salvage therapy in platinum-sensitive epithelial ovarian carcinoma: A Gynecologic Oncology Group Study

PURPOSE

Topotecan is known to be active in recurrent ovarian cancer, but most prior studies have focused on platinum-resistant or refractory populations. This study was undertaken to define the response rate and progression-free interval in platinum-sensitive patients.

PATIENTS AND METHODS

Patients with recurrent ovarian cancer after one or two prior chemotherapy regimens and in whom the interval between prior platinum therapy and the initiation of protocol therapy was greater than 6 months were treated with topotecan 1.5 mg/m(2) intravenously over 30 minutes daily for 5 days, with this cycle repeated every 21 days.

RESULTS

Forty-eight patients were entered onto the study; 47 were assessable for toxicity and 46 for response. The response rate was 33% (two complete responses and 13 partial responses), with a median response duration of 11.2 months. Hematologic toxicity predominated but was manageable in most patients with frequent incorporation of cytokines and RBC and platelet transfusions. Fatigue was reported in 15 patients and resulted in the discontinuation of therapy in five responding patients.

CONCLUSION

Topotecan is an active drug in platinum-sensitive ovarian cancer, with significant but manageable hematologic toxicity. Fatigue is also a common problem that may be dose-limiting in some patients.