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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Tuesday, January 14, 2025
For patients with hormone receptor (HR)-positive, HER2-positive breast cancer, combination therapy with the CDK4/6 inhibitor palbociclib, anti-HER2 therapy, and endocrine therapy may improve clinical outcomes, according to the results of the PATINA study, presented at the 2024 San Antonio Breast Cancer Symposium (Abstract GS2-012). The favorable safety profile associated with this therapeutic strategy reinforces its implementation as the standard of care for this patient population, according to Otto Metzger, MD, of Dana-Farber Cancer Institute, Boston, and colleagues.
From 2017 to 2021, a total of 518 patients with metastatic HR-positive and HER2-positive breast cancer were recruited for the study. Patients were randomly assigned to receive combination treatment with palbociclib, anti-HER2 therapy, and endocrine therapy (n = 261) or to the control arm with combination treatment of anti-HER2 therapy and endocrine therapy (n = 257). Anti-HER2 therapies included the monoclonal antibody pertuzumab or trastuzumab, and endocrine therapies included aromatase inhibitors or fulvestrant.
The addition of palbociclib led to a significantly improved progression-free survival (hazard ratio = 0.74). Patients treated with palbociclib had a median progression-free survival of 44.3 months, whereas patients in the control arm had a median progression-free survival of 29.1 months. Furthermore, the clinical benefit rate was 89.3% and 81.3% for patients treated with palbociclib and patients in the control arm, respectively. The objective response rate was significantly higher for patients treated with palbociclib (29.2%) compared with those in the control arm (22.2%). Although the overall survival analysis remained immature at the time of presentation, the median overall survival was not reached with palbociclib vs 77.0 months without it.
As for toxicity, grade 3 neutropenia was the most frequent adverse event linked to the use of palbociclib, and grades 2 and 3 fatigue, stomatitis, and diarrhea were reported more often with palbociclib. However, no significant differences in treatment-related adverse events were noted in either arm of the study.
Disclosure: For full disclosures of the study authors, visit sabcs.org.
2024 San Antonio Breast Cancer Symposium
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