In the phase II PATRICIA trial reported in the Journal of Clinical Oncology, Nancy U. Lin, MD, and colleagues found that pertuzumab plus high-dose trastuzumab produced central nervous system objective responses and clinical benefit in 68% of patients with HER2-positive metastatic breast cancer with progressive brain metastases.

Long-term analysis of the Short-HER trial showed that 9 weeks of adjuvant trastuzumab conveyed benefits comparable to a 1-year course in patients with early HER2-positive breast cancer deemed to be at low or intermediate risk for disease recurrence. High-risk patients, however, derived considerably more benefit from the conventional longer course, and the study did not meet the noninferiority threshold of significance, investigators reported at the ESMO Breast Cancer Virtual Congress 2021.

"It is incredible to reflect upon the scientific advances in the treatment of HER2-positive breast cancer over the past 23 years. Once considered the worst subtype of breast cancer, HER2-positive disease is now associated with the best long-term outcomes in this age of targeted treatments. With a total of eight U.S. Food and Drug Administration (FDA)-approved HER2-directed therapies for advanced disease, four in just the past ~18 months, clinicians and patients now have a number of tools available from which to choose. Though level 1 evidence clearly dictates the current gold standard in the first- and second-line settings (taxane/trastuzumab/pertuzumab and ado-trastuzumab emtansine, respectively), we now have multiple options available after the second line, with no data to guide optimal sequencing," write Sara A. Hurvitz, MD, FACP, and Shiliang Zhang, MD.

Drug-related interstitial lung disease occurred in less than 16% of patients with HER2-positive metastatic breast cancer following treatment with trastuzumab deruxtecan-nxki at the approved dose of 5.4 mg/kg. In addition, the majority of these cases were classified as grade 1 or 2, according to findings presented by Charles A. Powell, MD, and colleagues at the ESMO Breast Cancer Virtual Congress 2021.

In the phase III KAITLIN trial, replacing adjuvant taxane and trastuzumab with ado-trastuzumab emtansine (T-DM1) in patients with HER2-positive, hormone receptor–negative breast cancer did not result in a significant improvement in invasive disease–free survival in the node-positive or intent-to-treat population. An updated biomarker analysis of the trial has now confirmed the lack of benefit with the newer regimen in all subgroups of interest, as reported at the ESMO Breast Cancer Virtual Congress 2021 by Otto Metzger, MD.

Recent clinical trials have been encouraging for the neoadjuvant or adjuvant use of immune checkpoint inhibitors in triple-negative breast cancer, but is this approach ready for the clinic? This question was addressed at PER’s Miami Breast Cancer Conference, held virtually this year, by Adam M. Brufsky, MD, PhD, Professor of Medicine at the University of Pittsburgh School of Medicine and Co-Director of the Comprehensive Breast Cancer Center.¹