Phase I study of toremifene in patients with advanced cancer

A phase I multicenter evaluation of a novel antiestrogen, toremifene, was undertaken in postmenopausal women with various advanced difficult-to-treat malignancies. One hundred and seven women were treated at one of six dosage levels (10, 20, 40, 60, 200, or 400 mg/d orally) for at least 8 weeks. Weekly evaluations for toxicity were conducted. The most common side effects were nausea (31%), vomiting (12%), and hot flashes (29%). Five patients were removed from the study for possible adverse reactions: three patients experienced hypercalcemia; one experienced tremulousness, fatigue, and inability to think clearly; and one had vaginal bleeding. Twelve patients died while on study, 11 with disease progression and one with a pulmonary embolus. Sex hormone-binding globulin (SHBG) levels increased and there was a modest decline in serum antithrombin III levels. Four of 48 assessable patients had partial responses: three with breast cancer and one with endometrial cancer. Toremifene was generally well tolerated at the doses tested.