Final Survival Data From TH3RESA Trial in Breast Cancer
In patients with previously treated HER2-positive metastatic breast cancer, ado-trastuzumab emtansine (formerly known as T-DM1) resulted in a 32% reduction in the risk of death when compared with physician’s choice of treatment, according to the final overall survival results of the phase III TH3RESA trial, reported by Ian E. Krop, MD, of the Dana-Farber Cancer Institute, and colleagues, in The Lancet Oncology.
“These data further solidify the role of trastuzumab emtansine in the management of patients with previously treated HER2-positive advanced breast cancer and validate HER2 as a therapeutic target even after multiple lines of previous therapy,” the investigators concluded.
The trial enrolled 602 patients previously treated with both trastuzumab and lapatinib (advanced setting), and a taxane (any setting), and with disease progression on at least 2 HER2-directed regimens in the advanced setting. At data cutoff in February 2015, 47% of patients in the physician’s choice group had crossed over to the study drug due to disease progression.
Despite this crossover, median overall survival was significantly longer with ado-trastuzumab emtansine (22.7 months) versus physician’s choice of treatment (15.8 months). Grade ≥ 3 adverse events occurred in 40% of the ado-trastuzumab emtansine group versus 47% of the physician’s choice treatment group.