Dr. Murthy on Dual HER2 Blockade in HER2+ Breast Cancer

Rashmi K. Murthy, MD, assistant professor, Department of Breast Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, discusses dual HER2 blockade in HER2-positive breast cancer.

Patients who have early-stage HER2-positive breast cancer with a tumor size greater than 2 cm or node-positive disease are currently treated with neoadjuvant trastuzumab (Herceptin), pertuzumab (Perjeta), and chemotherapy. This regimen is based on 2 phase II trials, NeoSphere and TRYPHAENA, explains Murthy. Both studies showed an improvement in pathological complete response when dual HER2-targeted therapy was combined with taxane-based chemotherapy compared with single HER2-targeted therapy alone.

Additionally, the results of the APHINITY trial showed a benefit, though small, in disease-free survival in the adjuvant setting. Since December 2017, pertuzumab has been FDA approved in the adjuvant setting. This calls into question which patients benefit from receiving adjuvant trastuzumab and pertuzumab for the duration of 1 year, says Murthy. Biomarkers will help physicians answer this question, though none have been identified to date. Therefore, the decision rests on clinical judgement and patient comorbidities, says Murthy.