On June 24, 2026, the U.S. Food and Drug Administration (FDA) approved palbociclib (Ibrance) in combination with trastuzumab, with or without pertuzumab, and endocrine therapy for the maintenance treatment of adult patients with hormone receptor (HR)-positive, HER2-positive locally advanced or metastatic breast cancer following induction treatment.
PATINA
The efficacy of the regimen was evaluated in PATINA (Clinicaltrials.gov identifier NCT02947685), a randomized, open-label trial in 518 patients with HR-positive, HER2-positive locally advanced or metastatic breast cancer who had no evidence of disease progression after induction treatment with a taxane and trastuzumab, with or without pertuzumab. Patients were randomly assigned 1:1 to receive either palbociclib with trastuzumab, with or without pertuzumab, and endocrine therapy or trastuzumab, with or without pertuzumab, and endocrine therapy alone. Endocrine therapy consisted of fulvestrant or an aromatase inhibitor (anastrozole, letrozole, or exemestane). Patients received treatment until disease progression or unacceptable toxicity.
The major efficacy outcome measure was investigator-assessed progression-free survival per Response Evaluation Criteria in Solid Tumors version 1.1. Overall survival was an additional efficacy outcome measure.
A statistically significant improvement in investigator-assessed progression-free survival was observed for palbociclib with trastuzumab, with or without pertuzumab, and endocrine therapy compared to trastuzumab, with or without pertuzumab, and endocrine therapy alone (hazard ratio = 0.76; 95% confidence interval = 0.59–0.97; 1-sided P-value = .0134). The median progression-free survival could not be adequately described because of censoring. At the time of the progression-free survival analysis, overall survival data were not yet mature.
The palbociclib prescribing information includes warnings and precautions for neutropenia, interstitial lung disease/pneumonitis, and embryo-fetal toxicity.
Recommended Dosage
The recommended palbociclib dosage is 125 mg orally once daily for 21 consecutive days, followed by 7 days off treatment, to comprise a complete cycle of 28 days. Recommended dosages for trastuzumab, pertuzumab, and endocrine therapy can be found in the prescribing information.
This review used the Assessment Aid, a voluntary submission from the applicant to facilitate the FDA’s assessment.
Palbociclib had received a Breakthrough Therapy designation.
