Persistence to palbociclib treatment in HR+/HER2– breast cancer patients: A real-world study

Abstract

Objective

To evaluate adherence and persistence to palbociclib treatment in patients with advanced HR+/HER2– breast cancer in real-world clinical practice.

Methods

This observational, retrospective study was conducted using electronic medical records from two regional hospitals. Patients with locally advanced or metastatic HR+/HER2– breast cancer who initiated palbociclib treatment between January 2017 and December 2024 were included. Adherence was assessed using the medication possession ratio (MPR), and persistence was evaluated through the Kaplan–Meier method.

Results

Eighty-two patients were included, with a median age of 69 years. Treatment adherence was 92.7% (MPR ≥80%). Median treatment persistence was 40.9 months (IQR: 3.3), with rates of 83.2% at 6 months, 72.2% at 12 months, and 57.9% at 24 months. A total of 47.6% of patients discontinued treatment, mainly due to disease progression (37.8%) or toxicity (9.8%). The most frequent adverse events were neutropenia (72.0%) and anemia (63.3%).

Conclusions

Palbociclib demonstrated high adherence and persistence in real-world clinical practice, with a discontinuation rate comparable to that of previous clinical trials.