The U.S. Food and Drug Administration approved a new therapy regimen for patients with "double-positive" metastatic breast cancer on July 6, based on results from the phase 3 PATINA study led by Otto Metzger, MD, Associate Medical Director of International Strategic Initiatives at Dana-Farber Cancer Institute. The approval follows findings that adding the CDK 4/6 inhibitor palbociclib to standard therapy resulted in a more than 15-month improvement in progression-free survival for patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-positive (HER2+) metastatic breast cancer.
The PATINA trial's results were published in the New England Journal of Medicine and presented at the San Antonio Breast Cancer Symposium in December 2024. Metzger said, "Resistance to dual anti-HER2 and endocrine therapy remains a central clinical challenge for patients with HR+, HER2+ metastatic breast cancer – even after an excellent response to initial treatment. Based on the results from the PATINA study, the addition of palbociclib in the maintenance phase can meaningfully extend the time patients go without their disease progressing. This approval gives oncologists a new, evidence-based option to optimize maintenance therapy for their patients with HR+, HER2+ disease."
Approximately 10% of all breast cancers are HR+, HER2+, also referred to as double-positive or triple-positive breast cancer. Despite recent advances in treatment, resistance to anti-HER2 and endocrine therapies continues to pose challenges, highlighting ongoing needs for novel therapeutic approaches.
In the PATINA study, participants with previously treated metastatic disease were randomized either to receive palbociclib along with anti-HER2 and endocrine therapies or only anti-HER2 and endocrine therapies. The primary endpoint was progression-free survival as assessed by investigators. Patients receiving palbociclib plus anti-HER2 therapy (trastuzumab or trastuzumab plus pertuzumab) and endocrine therapy had a median progression-free survival of 44.3 months compared to 29.1 months among those who received only anti-HER2 and endocrine therapies—an extension exceeding 15 months.
PATINA was sponsored by Alliance Foundation Trials, LLC (AFT) in collaboration with six international cancer research groups across several countries including the United States, France, Germany, Italy, Spain, Australia, and New Zealand; funding support was provided by Pfizer.
