Bortezomib + Capecitabine

The combination of bortezomib and capecitabine is a therapeutic regimen studied primarily in patients with metastatic breast cancer previously treated with anthracyclines and/or taxanes. Bortezomib (Velcade) is a first-in-class selective inhibitor of the 26S proteasome, leading to cell cycle arrest and apoptosis of cancer cells. Capecitabine (Xeloda) is an oral fluoropyrimidine that functions as a nucleoside metabolic inhibitor. Phase I/II trials have evaluated this combination, determining maximum tolerated doses (MTDs) as bortezomib 1.3 mg/m² and capecitabine 2500 mg/m². The combination was generally well tolerated, with an intent-to-treat overall response rate of 15% and an additional 27% of patients achieving stable disease. The median time to progression was 3.5 months, and median overall survival was 7.5 months. Researchers concluded it has moderate antitumor activity in heavily pretreated patients with metastatic breast cancer.