[Treatment of advanced breast cancer in postmenopausal women with droloxifene: results of a double-blind phase II trial for dose determination].

To determine the optimal daily dose of a new antiestrogen, droloxifene, for the treatment of advanced breast cancer, we have conducted a multicenter, randomized, double blind trial. Postmenopausal women with advanced breast cancer, who could not benefit from loco regional therapy, with positive or unknown estrogen or progesterone receptors were entered in this study. Droloxifene was administered in a double blind randomized design, with daily dose of either 20 (group I), 40 (group II) or 100 mg (group III). None of the patients had received previous systemic antitumor therapy, with the exception of adjuvant chemotherapy terminated at least one year before the patient's recruitment. Patients with at least one measurable tumoral lesion were entered into the trial. Three hundred and sixty nine patients have been enrolled, 234 are fully evaluable for efficacy. Objective response rate (CR + PR) is 31.1, 44.6 and 41.9% for the groups I, II and III respectively (P = NS). Time to response has been short: in the three groups, 50% of the responses have been observed within the 2 first months of treatment. Time to disease progression is 6, 8.3 and 6 months respectively for the 20, 40 and 100 mg/day treatment group. Side effects have been moderate and not dose related. Hot flushes and gastro intestinal disorders have been observed most often. This promising new drug deserves further study and randomized comparison versus tamoxifen.