[Primary endocrine therapy as pre- and perimenopausal metastatic breast carcinoma with leuprorelin acetate depot. German Leuprorelin Study Group].

In an open, prospective, multicentre phase III clinical trial 73 patients with newly diagnosed, metastatic breast cancer were enrolled. Most of them were hormone-receptor-positive. All patients were pre- or perimenopausal and treated with monthly sc. injections of 3.75 mg leuprorelinacetate-depot as monotherapy until disease progression. 50/73 patients (68.5%) had low-risk metastatic disease. A marked reduction of gonadotropin levels resulted in a profound and sustained suppression of the oestradiol levels to castration range (30 pg/ml) during the entire treatment period. The overall response rate based on the best response during treatment was as follows: CR + PR in 25/73 (34.2%) [25.1-44.4%] and CR + PR + SD in 42/73 patients (58%) [47.2-67.4%] respectively. The median time to progression (TTP) was 6 months and the median overall survival (OS) 24.3 months. Both parameters differed significantly when responder (CR/PR) and non-responder (NC/PD) were compared: 18.6 +/- 2.4 [13.9-23.4] vs. 5.8 +/- 0.6 [4.7-7.0] months (TTP, p < 0.0001) and 41.5 +/- 3.0 [35.5-47.5] vs. 15.6 +/- 2.4 [11.3-20.5] months (OS, p = 0.0019). The median duration of response was 12 (range: 3-48) months. Premenopausal low-risk patients without previous adjuvant treatment after primary surgery showed the best response during the GnRHa treatment. The main side effects (hot flushes, increased sweating, headache etc.) were related to oestradiol suppression. Treatment was well tolerated leading in only one case to a premature withdrawal due to side effects. Leuprorelinacetate-depot is a safe and effective palliative drug for pre- and perimenopausal metastatic breast cancer patients. Like other GnRH-agonists which have been evaluated for this indication, leuprorelinacetate-depot can be used as first-line endocrine treatment in these patients.