DURATION OF REMISSION TO ICI-182,780 COMPARED TO MEGESTROL-ACETATE INTAMOXIFEN-RESISTANT BREAST-CANCER

Recently we reported that treatment with the specific (pure) antioestr ogen, ICI 182,780, in 19 patients with advanced breast cancer resistan t to tamoxifen resulted in a high response rate and a long median dura tion of remission (> 22 months). In order to assess the relative value of ICI 182,780 in this clinical situation we have compared its activi ty with that of megestrol acetate, the standard second-line endocrine therapy in a group of similarly selected patients. Each ICI 182,780 tr eated patient was matched with three patients who received megestrol a cetate (n = 57). Both groups were previously treated with tamoxifen. P atients were matched for age, site of metastases, prior tamoxifen ther apy (for adjuvant or advanced disease) and therapeutic response to tam oxifen where given for advanced disease and therapeutic response to se cond-line therapy (i.e. ICI 182,780 or megestrol acetate). The duratio n of remission (PR or SD) was significantly longer for patients treate d with ICI 182,780 compared to megestrol acetate (26 months and 14 mon ths respectively, P = 0.04). These findings support further clinical c omparison between ICI 182,780 and established endocrine agents.