Fulvestrant in heavily pretreated ER-positive postmenopausal metastatic breast cancer patients: A phase II study.

1144 Background: Fulvestrant (F), an estrogen receptor down-regolator drug, has been demonstrated to be effective in ER +ve postmenopausal metastatic breast cancer (MBC) progressing on tamoxifen (Howell A., 1995) and phase III trials have shown that response rates, TTP e OS are comparable to those obtained with anastrozole (Howell A., 2000 and Mauriac L., 2003).,The aim of the study was to evaluate efficacy and toxicity of F in ER+ve post-menopausal metastatic breast cancer patients (MBC pts) heavily pre-treated both with hormonal agents and chemotherapy. From 5/2006 to 10/2007 22 pts. in this setting, were treated with F 250 mg i.m. q 28 days.,All pts, median age 63 (range 39-81), had received prior anthracycline and taxane-based chemotherapy and had been treated with a median of 2 chemotherapy regimens (range 1-5), and a median of 3 hormonal agents (range 1-4). Sites of MBC were: 13 bone, 2 liver, 4 lung, 1 CNS, 5 nodes, 3 skin, 4 breast. The 22 pts received a total of 117 cycles of F: median 6 cycles/pt. (range 1-19+). All pts were valuable for toxicity and 19/22 for efficacy. Overall response rate (OR) was 4/19 (21%) (0CR, 4PR) and SD was observed in a further 4 pts (21%); clinical benefit (response+SD) was observed in 42,1% (8/19) of pts. Median TTP in all pts was 4+ mos (range 0,5-16+ mos.) and in pts obtaining clinical benefit was 7+ mos (range 2-16+mos). Median OS in the 22 pts was 7+ mos. (range1-16+ mos) and 12+ mos. (range 2-16+) in pts with clinical benefit. No G3-4 toxicities were observed: G1-2 cutaneous rash occurred in 3/22 (13.6%) pts. and G1-2 asthenia in 3/22 (13.6%) pts.,F can be safely administered to heavily pre-treated ER+ve post-menopausal MBC pts. Although phase III trials are lacking, results from this phase II study are comparable with the results obtained in pivotal trials when F was used as 2nd-line treatment, suggesting that F could have comparable efficacy in heavily pretreated MBC pts. No significant financial relationships to disclose.