Pfizer’s IBRANCE® Boosts Survival By 15+ Months In Metastatic Breast Cancer Study

Pfizer Inc. and Alliance Foundation Trials, LLC (AFT) shared positive results from the Phase 3 PATINA trial. The study showed that adding IBRANCE® (palbociclib) to the standard first-line maintenance therapy after chemotherapy significantly improved progression-free survival (PFS) in patients with HR+/HER2+ metastatic breast cancer.  

Patients receiving IBRANCE along with anti-HER2 therapy (trastuzumab or trastuzumab plus pertuzumab) and endocrine therapy had a median PFS of 44.3 months, compared to 29.1 months for those on anti-HER2 therapy and endocrine therapy alone. This means an improvement of over 15 months in median PFS. While overall survival data is not yet available, these findings were presented at the 47th San Antonio Breast Cancer Symposium (SABCS) during a late-breaking session.

Otto Metzger, M.D., principal investigator of the trial for Alliance Foundation Trials and Medical Oncologist at the Dana-Farber Cancer Institute, said in a statement, “PATINA is the first large Phase 3 study to show the benefit of CDK4/6 inhibition in HR-positive, HER2-positive metastatic breast cancer. These results support the potential of this maintenance treatment to slow disease progression and improve clinical outcomes in this patient population.”

Roger Dansey, M.D., Chief Development Officer, Oncology, Pfizer, also mentioned, “IBRANCE, the first CDK4/6 inhibitor, revolutionized the treatment of HR-positive, HER2-negative metastatic breast cancer, and has been prescribed to over 773,000 patients since its initial approval in 2015. These results demonstrate that the addition of IBRANCE to standard of care shows promise as maintenance therapy in HR-positive, HER2-positive disease. PATINA underscores Pfizer’s ongoing commitment to addressing the unmet needs of people with breast cancer, and we look forward to discussing the results with regulatory authorities.”

About 10% of breast cancers are HR+ and HER2+, often called double-positive or triple-positive breast cancer. While treatments have improved, resistance to anti-HER2 and endocrine therapies remains a challenge, highlighting the need for new treatment options for HR+, HER2+ metastatic breast cancer. Currently, IBRANCE is not approved for use in this type of cancer.

The safety of IBRANCE in the PATINA study matched its known safety profile for HR+, HER2- metastatic breast cancer, with no new concerns identified. The most common side effects were blood-related issues like neutropenia and leukopenia. Other side effects, such as fatigue, mouth sores, and diarrhea, were generally mild to moderate. Since its approval in 2015, IBRANCE has remained a standard first-line treatment for HR+, HER2- metastatic breast cancer and is approved in over 108 countries. Pfizer plans to share the PATINA study results with regulatory authorities.