Formal discussant Clifford Hudis, MD, ASCO President and Chief of the Breast Cancer Service at Memorial Sloan-Kettering Cancer Center in New York, commented that the findings were not surprising. “The results of TH3RESA nicely reflect the EMILIA trial and are consistent with those of anti-HER2 therapies. These antibody-based therapies have revolutionized the treatment of a subset of breast cancer patients.”

He said that ado-trastuzumab emtansine should be considered in HER2-positive disease as second-, third- or fourth-line treatment.

Remaining issues are the optimal sequencing of HER2-directed therapies and the best role for ado-trastuzumab emtansine, he added. He also said that there might be biomarkers (not yet identified) for subsets of patients with a preferential response to ado-trastuzumab emtansine. ■

Disclosure: Dr. Hudis reported no potential conflicts of interest.