Adjuvant chemotherapy for early-stage breast cancer: the tAnGo trial

The tAnGo trial is a randomized, open-label, multicenter phase III trial examining adjuvant treatment with epirubicin (Ellence)/cyclophosphamide (Cytoxan, Neosar) for four cycles followed by paclitaxel alone or combined with gemcitabine (Gemzar) for four cycles in patients with early-stage breast cancer. In the Cancer and Leukemia Group B (CALGB) 9344 trial, addition of paclitaxel to anthracycline/cyclophosphamide adjuvant therapy resulted in increased time to recurrence and improved survival. Because an unplanned subgroup analysis in CALGB 9344 indicated a significant benefit of paclitaxel in patients with estrogen receptor (ER)-negative disease but not ER-positive disease, the initial tAnGo trial design called for enrollment of patients with ER-negative disease. The tAnGo trial entry criteria were recently amended to allow any ER status, given experience suggesting that clinical benefit of taxane-containing regimens in ER-positive disease may emerge over a time frame longer than that required to detect benefit in ER-negative disease. Gemcitabine has been included as a partner for paclitaxel in the tAnGo trial based on high response rates, including high complete response rates, observed in phase II trials of the combination in more advanced disease and based on the tolerability and safety of the combination compared with those of other taxane-containing two-drug combinations. The tAnGo trial is currently accruing patients and has a target population of 3,000. Trial results should provide important information on the role of gemcitabine in adjuvant therapy for breast cancer.