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First and only CDK4/6 inhibitor approved for HR+ metastatic disease regardless of HER2 status
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Approval based on data from the collaborative Phase 3 PATINA trial, which showed a 24% risk reduction in disease progression for IBRANCE added to anti-HER2 and endocrine therapies
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Continues decade-long legacy of IBRANCE helping transform the treatment for HR+ metastatic breast cancer
June 24, 2026 --NEW YORK--(BUSINESS WIRE)-- Pfizer Inc. (NYSE: PFE) today announced the U.S. Food and Drug Administration (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 3 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+,i 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 3 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.
About IBRANCE® (palbociclib)
IBRANCE is an oral inhibitor of CDKs 4 and 6,ii which are key regulators of the cell cycle that trigger cellular progression.iii,iv In the U.S., IBRANCE is indicated for the treatment of adult patients with HR+, HER2- advanced or metastatic breast cancer in combination with an aromatase inhibitor as initial endocrine-based therapy; or with fulvestrant in patients with disease progression following endocrine therapy. IBRANCE is indicated in combination with inavolisib and fulvestrant for the treatment of adult patients with endocrine-resistant, PIK3CA-mutated, HR-positive, HER2-negative, locally advanced or metastatic breast cancer, as detected by an FDA-approved test, following recurrence on or after completing adjuvant endocrine therapy. IBRANCE is also indicated in combination with trastuzumab, with or without pertuzumab, and endocrine therapy for the maintenance treatment of adult patients with HR-positive, HER2-positive locally advanced or metastatic breast cancer following induction treatment.
About Pfizer Oncology
At Pfizer Oncology, we are at the forefront of a new era in cancer care. Our industry-leading portfolio and extensive pipeline includes three core mechanisms of action to attack cancer from multiple angles, including small molecules, antibody-drug conjugates (ADCs), and multispecific antibodies, including other immune-oncology biologics. We are focused on delivering transformative therapies in some of the world’s most common cancers, including breast cancer, gastrointestinal cancers, genitourinary cancers, hematology-oncology, and thoracic cancers, which includes lung cancer. Driven by science, we are committed to accelerating breakthroughs to help people with cancer live better and longer lives.
About Pfizer: Breakthroughs That Change Patients’ Lives
At Pfizer, we apply science and our global resources to bring therapies to people that extend and significantly improve their lives. We strive to set the standard for quality, safety and value in the discovery, development and manufacture of health care products, including innovative medicines and vaccines. Every day, Pfizer colleagues work across developed and emerging markets to advance wellness, prevention, treatments and cures that challenge the most feared diseases of our time. Consistent with our responsibility as one of the world's premier innovative biopharmaceutical companies, we collaborate with health care providers, governments and local communities to support and expand access to reliable, affordable health care around the world. For more than 175 years, we have worked to make a difference for all who rely on us.
References
i Kay C, Martinez-Peréz C, Meehan J, et al. Current trends in the treatment of HR+/HER2+ breast cancer. Future Oncol. 2021;17(13):1665-1681.
ii IBRANCE (palbociclib) Prescribing Information. New York. NY: Pfizer Inc: April 2025.
iii Weinberg, RA. pRb and Control of the Cell Cycle Clock. In: Weinberg RA, ed. The Biology of Cancer. 2nd ed. New York, NY: Garland Science; 2014:275-329.
iv Sotillo E, Grana X. Escape from Cellular Quiescence. In: Enders GH, ed. Cell Cycle Deregulation in Cancer. New York, NY: Humana Press; 2010:3-22.