Open phase II study of high-dose toremifene as first-line therapy for advanced breast cancer.

Abstract In an open phase II study conducted in Finland and Latvia, 73 postmenopausal women were treated with 240 mg of toremifene (Fareston) as first-line therapy for advanced breast cancer. Among the 56 patients evaluable for responses, 59% achieved objective responses [complete response (CR) plus partial response (PR)], 29% showed no change (NC), and 12% had progressive disease (PD). When all treated patients were included, the objective response rate was 47%. Several very long durations of responses up to 86 months and survival durations up to 95 months were observed. In assessable patients, the best objective response rates were seen in those with soft-tissue (74%) and visceral (60%) disease. In 54% of patients with very large inoperable primary cancers, a PR was achieved. Half of patients reported side effects, about 60% of which were mild; 30%, moderate; and 5%, severe. Based on response rate and safety, high-dose toremifene is useful as first-line therapy for advanced breast cancer.