Evolving HER2+ Metastatic Breast Cancer Landscape

• Published in: Oncology (Williston Park, N.Y.) Vol. 35; no. 12; p. 839
• Main Authors: Seidman, Andrew D, Bardia, Aditya, Pegram, Mark, Rao, Ruta
• Format: Journal Article
• Language: English
• Published: Monmouth Junction Intellisphere, LLC 01.12.2021; MultiMedia Healthcare Inc
• Subjects: Antimitotic agents; Antineoplastic agents; Breast cancer; Cancer therapies; Care and treatment; Chemotherapy; Medicine; Metastasis; Oncology; Patients; United States > US; Massachusetts
• ISSN: 0890-9091; 2767-7389

The other panelists were Aditya Bardia, MD, MPH, a breast medical oncologist at Massachusetts General Hospital and assistant professor of medicine at Harvard Medical School in Boston, Massachusetts; Mark Pegram, MD, a professor of medical oncology at the Stanford University School of Medicine in California; and Ruta Rao, MD, who is associate professor in the Department of Internal Medicine, Division of Hematology, Oncology, and Cell Therapy at Rush Medical College; director, Coleman Foundation Comprehensive Breast Cancer Clinic; and medical director, Rush University Cancer Center, all in Chicago, Illinois. The primary end point was progression-free survival (PFS) as determined by independent review; secondary outcomes included OS, PFS as determined by investigators, objective response rate, duration of objective response, and time to disease progression. Trastuzumab emtansine was found to significantly improve PFS, and it lowered overall toxicity compared with capecitabine and lapatinib at the first analysis (HR, 0.65; 95% CI, 0.55-0.77; P .001), with the final descriptive analysis revealing a 25% reduction in the risk of disease progression or death (HR, 0.75; 95% CI, 0.64-0.88).3,4 The 2021 American Society of Clinical Oncology meeting saw the presentation of updated results from the pivotal phase 3 HER2CLIMB study (NCT02614794) that randomized 612 patients with unresectable metastatic or locally advanced HER2-positive breast cancer in a 2:1 fashion to receive either trastuzumab and capecitabine alone or in combination with tucatinib (Tukysa). Investigators reported a survival benefit in the tucatinib group 15.6 months following the primary analysis, with patients assigned to tucatinib experiencing a 5.5-month improvement in OS compared with the placebo group (HR, 0.73; 95% CI, 0.59-0.90; P = .004).8 Data from DESTINY-Breast03 in 524 patients randomly assigned to T-DXd vs T-DM1 that were presented at the European Society for Medical Oncology 2021 Congress indicated that the median PFS was not reached in the trastuzumab deruxtecan group compared with 6.8 months in the T-DM1 group (HR, 0.28; 95% CI, 0.22-0.37; P = 7.8 × 10-22).