FDA approves Ibrance (palbociclib) regimen for HR+, HER2+ metastatic breast cancer frontline maintenance – Pfizer
Pfizer Inc. announced the FDA approved Ibrance (palbociclib) in combination with trastuzumab, with or without pertuzumab, and endocrine therapy for the maintenance treatment of adult patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-positive (HER2+) locally advanced or metastatic breast cancer (MBC) following induction treatment. The approval is based on positive results from the Alliance Foundation Trials, LLC (AFT)-sponsored Phase III PATINA trial.
“Over the past decade, IBRANCE has helped transform metastatic breast cancer treatment, establishing CDK4/6 inhibition as a cornerstone of care,” said Aamir Malik, Chief U.S. Commercial Officer and Executive Vice President, Pfizer. “With today’s FDA approval, Ibrance becomes the first and only CDK4/6 inhibitor indicated for patients with HR+ metastatic breast cancer regardless of HER2 status, extending its impact to patients who continue to face challenges with treatment resistance. This milestone strengthens confidence in Ibrance as a CDK4/6 inhibitor backbone across combination regimens, reflecting Pfizer’s ongoing leadership in delivering meaningful advances for people with breast cancer.”
The PATINA trial demonstrated a 24% reduction in the risk of progression or death following induction treatment with the addition of Ibrance to anti-HER2 (trastuzumab or trastuzumab plus pertuzumab) and endocrine therapies compared to anti-HER2 and endocrine therapies alone (HR: 0.76 [95% CI, 0.59, 0.97]; one-sided p=0.0134). The safety and tolerability of Ibrance in PATINA were consistent with its known safety profile. The most commonly reported adverse events with Ibrance were hematologic toxicities, such as white blood cell decreased and neutrophil count decreased. Non-hematologic adverse events included diarrhea, infections, stomatitis, and fatigue, which were generally mild to moderate in severity. Results from the trial were previously published by AFT in the New England Journal of Medicineand presented at the 2024 San Antonio Breast Cancer Symposium.
“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,” said Otto Metzger, M.D., principal investigator of the trial for Alliance Foundation Trials and Medical Oncologist at the Dana-Farber Cancer Institute. “Based on the results from the PATINA study, the addition of Ibrance 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+, which is sometimes referred to as double-positive or triple-positive breast cancer. Historically, there has been limited research specifically focused on the HR+, HER2+ subtype in MBC, and PATINA is the first registrational study to explore the potential of CDK4/6 inhibition in this subtype.
Since its initial regulatory approval in 2015, Ibrance continues to be a standard-of-care first-line treatment for HR+, HER2- MBC and has been prescribed to more than 900,000 patients and approved in more than 100 countries.
About the PATINA Trial
PATINA (AFT-38) was a randomized, open-label global Phase III study to evaluate the efficacy and safety of Ibrance (palbociclib) in combination with anti-HER2 therapy (trastuzumab or trastuzumab plus pertuzumab) and endocrine therapy compared to anti-HER2 therapy and endocrine therapy alone as a first-line maintenance therapy (following induction treatment) for patients with HR+, HER2+ MBC. While Pfizer provided funding support for the trial, PATINA was also supported by an academic collaboration led by Alliance Foundation Trials, LLC (AFT) as the global sponsor in partnership with six international cancer research groups in the U.S.(PrECOG), France (French Breast Cancer Intergroup Unicancer), Germany (GBG), Italy (Fondazione Michelangelo), Portugal and Spain (SOLTI), and Australia and New Zealand (Breast Cancer Trials). Study participants who received a median of 6 cycles of induction treatment were randomized to receive Ibrance, in addition to anti-HER2 therapy and endocrine therapy (n=261), or anti-HER2 therapy and endocrine therapy alone (n=257). The primary endpoint was progression-free survival (PFS) as assessed by the investigator. Overall survival is a secondary endpoint and is not yet mature.
Citation: Palbociclib for Hormone-Receptor–Positive, HER2-Positive Advanced Breast Cancer. Authors: Otto Metzger, M.D., Sumithra Mandrekar, Ph.D., Shom Goel, M.D., et al. Published January 28, 2026 N Engl J Med 2026;394:451-462 DOI: 10.1056/NEJMoa2511218 VOL. 394 NO. 5
