Mature results of a randomized phase II multicenter study of exemestane versus tamoxifen as first-line hormone therapy for postmenopausal women with metastatic breast cancer

• Published in: Annals of oncology Vol. 14; no. 9; pp. 1391 - 1398
• Main Authors: Paridaens, R., Dirix, L., Lohrisch, C., Beex, L., Nooij, M., Cameron, D., Biganzoli, L., Cufer, T., Duchateau, L., Hamilton, A., Lobelle, J. P., Piccart, M.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-09-2003
• Subjects: Adult; Aged; Aged, 80 and over; Androstadienes - adverse effects; Androstadienes - therapeutic use; Antineoplastic agents; Antineoplastic Agents, Hormonal - adverse effects; Antineoplastic Agents, Hormonal - therapeutic use; Biological and medical sciences; Breast Neoplasms - drug therapy; Breast Neoplasms - secondary; Chemotherapy; Female; hormone therapy; Humans; Key words: aromatase inactivators; Medical sciences; metastatic breast cancer; Middle Aged; Pharmacology. Drug treatments; Postmenopause; Tamoxifen - adverse effects; Tamoxifen - therapeutic use; Treatment Outcome; Antineoplastic agent; Steroid; Multicenter study; Antiestrogen; Antihormone; Estrogen synthase; Randomization; Phase II trial; Postmenopause; Female; Advanced stage; Mammary gland; hormone therapy; Non steroid compound; Human; Enzyme; Enzyme inhibitor; Malignant tumor; Exemestane; Androstane derivatives; Tamoxifene; First line treatment; Mammary gland diseases; aromatase inactivators; Chemotherapy; Treatment; metastatic breast cancer; Metastatic; Hormone replacement therapy; Comparative study
• ISSN: 0923-7534; 1569-8041
• DOI: 10.1093/annonc/mdg362

Background: Women with hormone-responsive metastatic breast cancer (MBC) may respond to or have stable disease with a number of hormone therapies. We explored the efficacy and safety of the steroidal aromatase inactivator exemestane as first-line hormonal therapy in MBC in postmenopausal women. Patients and methods: Patients with measurable disease were eligible if they had received no prior hormone therapy for metastatic disease and had hormone receptor positive disease or hormone receptor unknown disease with a long disease-free interval from adjuvant therapy. They were randomized to tamoxifen 20 mg/day or exemestane 25 mg/day in this open-label study. Results: Blinded independently reviewed response rates for exemestane and tamoxifen were 41% and 17%, respectively. Fifty-seven per cent of exemestane- and 42% of tamoxifen-treated patients experienced clinical benefit, defined as complete or partial response, or disease stabilization lasting at least 6 months. There was a low incidence of severe flushing, sweating, nausea and edema in women who received exemestane. One exemestane-treated patient had a pulmonary embolism with grade 4 dyspnea. Conclusions: Exemestane is well tolerated and active in the first-line treatment of hormone-responsive MBC. An ongoing EORTC phase III trial is comparing the efficacy, measuring time-to-disease progression, of exemestane and tamoxifen.