Celecoxib and exemestane versus placebo and exemestane in postmenopausal metastatic breast cancer patients: a double-blind phase III GINECO study.

The aim of this study was to evaluate antitumor effects of cyclooxygenase-2 inhibitors in breast carcinoma and their ability to act synergistically with aromatase inhibitors (AIs). Postmenopausal metastatic breast cancer patients without previous adjuvant AI treatment received exemestane 25 mg/days plus either celecoxib 400 mg twice daily or placebo. The primary endpoint was progression-free survival (PFS). This trial was prematurely terminated (N = 157 of 342 planned) after cardiovascular toxicity was reported in other celecoxib trials. Although no PFS difference was observed between the two arms (9.8 months for both, P = 0.72), a trend favoring celecoxib was observed in 60 tamoxifen-resistant patients (9.6 vs. 5.1 months; P = 0.14) and in 126 patients treated >or=3 months before study termination (12.2 vs. 9.8 months; P = 0.09). No severe adverse events were reported. Cyclooxygenase-2 inhibitors seemingly contribute to reverse endocrine resistance in breast cancer patients, although further study is necessary to allow development of a new therapeutic strategy.