Early Breast Cancer
Right-sizing therapy, meaning identifying the right treatment for every patient, is a key element of new research in early breast cancer, said Erika Hamilton, MD, of the Sarah Cannon Research Institute, Nashville, Tenn.
She highlighted safety and treatment duration updates from the NATALEE study, which compared adjuvant ribociclib plus nonsteroidal aromatase inhibitor (NSAI) to NSAI alone for ER+/HER2- breast cancer. The current analysis presented at the meeting showed significant benefits with the addition of ribociclib and no evidence of new safety signals or adverse event exacerbations at 3 years, she said. Dose modifications had no significant impact on efficacy, she added.
The findings of no impact of dose reduction on efficacy in both the NATALEE and monarchE studies provide important information on whether dosage can be reduced in patients, which will increase the odds that patients will tolerate extended therapy with good outcomes and stay on their prescribed therapies, Dr. Hamilton emphasized.
The CARABELA study, a phase 2 trial of neoadjuvant letrozole plus abemaciclib vs adriamycin and cyclophosphamide (AC), showed clinically similar response rates but did not meet its endpoint for residual cancer burden (RCB) scores. These data add to results from other studies and show that it is too soon to universally replace neoadjuvant chemotherapy as first-line treatment for highly proliferative ER+ breast cancer, Dr. Hamilton said in her presentation.
Advanced Breast Cancer
Take-home messages about advanced breast cancer include growing evidence for the potential benefits of antibody drug conjugates (ADCs), said Eva Ciruelos, MD, of University Hospital, Madrid, Spain. The TROPION-BREAST01 study, a phase 3 randomized trial, showed significant and clinically meaningful improvement in progression-free survival in patients with previously treated, inoperable, or metastatic HR+/HER2- breast cancer who received datopotamab deruxtecan (Dato-DXd) compared with those who received chemotherapy.
Data from an additional safety analysis were presented at the meeting; although Dato-DXd, a trophoblast cell-surface antigen 2 (TROP2)–directed antibody-drug conjugate, was well-tolerated, it is important to remain aware of toxicities, notably oral mucositis, which occurred in 55.6% of the patients in the study across all grades, and ocular surface toxicity, which occurred in 40% of patients across all grades, Dr. Ciruelos emphasized.
Key research in the area of advanced triple-negative breast cancer included data from the IMPASSION 132 study. This study is “specifically centered on early relapsers,” a population often excluded from other trials, Dr. Ciruelos said. In this study, patients with advanced triple-negative breast cancer were randomized to chemotherapy with or without atezolizumab, and the study showed no benefits with atezolizumab for overall survival, progression-free survival, or overall response rate, she said. “This is something to work with, because this is a very refractory population,” Dr. Ciruelos noted.
New immunotherapy combinations are needed to improve survival in advanced breast cancer patients, Dr. Ciruelos said. At the meeting, researchers presented interim data from a subset of patients in the MORPHEUS-pan breast cancer trial, a phase 1B/2 study involving multiple treatment combinations in locally advanced/metastatic breast cancer patients.
The interim analysis included 18-week data from triple-negative breast cancer patients and compared outcomes for patients randomized to atezolizumab with or without sacituzumab govitecan (SG).