Dual HER2 Blockade Fails to Improve Response Rate in HER2-Positive Breast Cancer

“Dual HER2 blockade with trastuzumab and lapatinib was no better than trastuzumab alone in producing pathologic complete responses (pCR) in metastatic HER2-positive breast cancer patients in the neoadjuvant setting, according to a new study. Those with hormone receptor–negative disease did see an improvement with the dual blockade.

“ ‘In randomized neoadjuvant trials, dual HER2 targeting generally results in higher pCR rates, but the magnitude of this effect has varied,’ wrote study authors led by Lisa A. Carey, MD, of the University of North Carolina at Chapel Hill. The new trial was a three-arm study of preoperative therapy in 305 patients with stage II/III HER2-positive breast cancer; 118 patients were randomized to paclitaxel along with trastuzumab and lapatinib, 120 to paclitaxel with trastuzumab alone, and another 67 to paclitaxel along with only lapatinib. That last trial arm was closed early. Results were published online ahead of print in the Journal of Clinical Oncology.”