FDA Approves Palbociclib for HR+/HER2+ Metastatic Breast Cancer Maintenance

On June 24, the U.S. Food and Drug Administration (FDA) announced the approval of palbociclib (Ibrance) for a new indication in the oncology space. This approval specifically covers palbociclib in combination with trastuzumab (Hercdptin), with or without pertuzumab (Perjeta), and endocrine therapy for the maintenance treatment of adults with hormone receptor (HR)-positive, HER2-positive locally advanced or metastatic breast cancer who have completed induction treatment.

The regulatory decision was supported by results from the PATINA trial (NCT02947685), a randomized, open-label, international study involving 518 patients. Participants in the trial had HR-positive, HER2-positive metastatic disease and had shown no evidence of disease progression following an initial induction phase. This induction treatment consisted of a taxane and trastuzumab, with or without pertuzumab.

Following induction, patients were randomized in a 1:1 ratio to receive either the palbociclib-based combination regimen or a control regimen consisting of trastuzumab, with or without pertuzumab, and endocrine therapy alone. The endocrine therapy component in the trial included options such as fulvestrant (Faslodex) or an aromatase inhibitor, specifically anastrozole, letrozole, or exemestane. Treatment continued until patients experienced disease progression or unacceptable toxicity.The primary efficacy outcome of the PATINA trial was progression-free survival (PFS) as assessed by investigators using RECIST version 1.1. Data demonstrated a statistically significant improvement in PFS for the palbociclib arm compared to the control group. The reported hazard ratio was 0.76 (95% CI: 0.59, 0.97), with a 1-sided p-value of 0.0134. While the PFS benefit was clear, researchers noted that median PFS could not be adequately described at the time of analysis due to censoring, and overall survival (OS) data remained immature.

For oncology nurses and healthcare providers, understanding the recommended dosage and safety profile is essential for patient management. The approved palbociclib dosage is 125 mg taken orally once daily for 21 consecutive days. This is followed by a seven-day rest period to complete a standard 28-day treatment cycle. Nurses should also consult the specific prescribing information for the appropriate dosages of the accompanying trastuzumab, pertuzumab, and endocrine therapies.

Safety monitoring is a critical component of care for patients receiving this regimen. The prescribing information for palbociclib includes significant warnings and precautions regarding the risk of neutropenia, interstitial lung disease (ILD)/pneumonitis, and embryo-fetal toxicity. Close clinical observation and patient education regarding these potential adverse events are necessary to ensure safety throughout the maintenance phase.

The FDA granted palbociclib a breakthrough therapy designation for this indication, highlighting the clinical importance of providing new maintenance options for this specific patient population. This review also utilized the Assessment Aid, a voluntary submission from the manufacturer intended to streamline the FDA’s evaluation process.

Full prescribing information will be available through the Drugs@FDA database. Healthcare professionals are encouraged to report any serious adverse events to the FDA’s MedWatch Reporting System to continue monitoring the drug's safety profile in the post-marketing setting.

Reference

1. U.S. Food and Drug Administration. FDA approves palbociclib with trastuzumab, with or without pertuzumab, and endocrine therapy for the maintenance treatment of HR-positive, HER2-positive metastatic breast cancer. FDA.gov. Published June 24, 2026. Accessed June 24, 2026. https://www.fda.gov/drugs/resources-information-approved-drugs/fda-approves-palbociclib-trastuzumab-or-without-pertuzumab-and-endocrine-therapy-maintenance