Ongoing trials with trastuzumab in metastatic breast cancer

Following the pivotal clinical trials of trastuzumab (Herceptin), further p hase II and III studies have been initiated. Preliminary results from a pha se II, dose-response study of single-agent trastuzumab in 113 HER2-positive metastatic breast cancer patients without prior chemotherapy for stage IV disease have shown that the overall response rate was 23% (six complete res ponses and 20 partial responses), with similar results using both standard- and high-dose regimens of trastuzumab. Another phase II study of trastuzum ab plus paclitaxel, both given weekly, in 63 HER2-positive and -negative pa tients with metastatic breast cancer produced an overall response rate of 6 2% in HER2-positive and 44% in HER2-negative patients. A further phase II s tudy is underway to investigate the combination of trastuzumab plus docetax el in 30 HER2-positive patients with metastatic breast cancer. Finally, a n umber of European studies are at an advanced stage of planning or are about to start patient recruitment. These include docetaxel +/- trastuzumab, aro matase inhibitor +/- trastuzumab, CMF (cyclophosphamide, methotrexate, 5-fl uorouracil) +/- trastuzumab, vinorelbine + trastuzumab, all in HER2-positiv e patients, and epirubicin-cyclophosphamide (EC) + trastuzumab in HER2-posi tive patients vs. EC alone in HER2-negative patients. The results from thes e trials should be available over the next one to two years.