Work

Safety and clinical outcomes of pembrolizumab standard-interval dosing versus extended-interval dosing in patients with breast cancer

Year: 2025

Type: article

Abstract: INTRODUCTION: Extended-interval (EI) dosing of pembrolizumab (400 mg IV every 6 weeks) was approved across all solid tumors based on pharmacokinetic modeling and exposure-response analyses. Although EI dosing is more convenient for patients, whether the higher dose and extended dosing interval impacts immune-related adverse events (irAE) and clinical outcomes in patients with breast cancer is unknown. METHODS: In this retrospective cohort study, patients with breast cancer treated with pembrolizumab between 2017 and 2024 were included. Safety (irAE) and clinical outcomes including event-free survival (EFS), progression-free survival (PFS) and overall survival (OS) were compared between patients who received only standard-interval (SI) dosing (200 mg IV every 3 weeks) pembrolizumab and those who received ≥ 1 cycle of EI dosing. RESULTS: Of the 355 patients included, 59 (17%) received ≥ 1 cycle of EI and 296 (83%) received ≥ 1 cycle of only SI. Of those who received ≥ 1 cycle of pembrolizumab EI, 27 (45.8%) started with 200 mg, 7 (11.9%) started with 400 mg, 9 (15.2%) received only 400 mg, and 16 (27.1%) switched between dosing schedules. The majority (71%) of patients had early-stage disease, and 92% had triple-negative breast cancer. In patients with early-stage disease, rates of any-grade irAE were similar (p = 0.3), while grade 3 or higher irAE was lower in EI dosing versus SI (4% vs. 20%; p = 0.01). EFS and OS were similar between the two dosing regimens (p = 0.8 and p = 0.5, respectively). In patients with metastatic disease, any-grade irAE (p = 0.5), grade 3 or higher irAE (p = 0.1), PFS (p = 0.8), and OS (p = 0.5) were similar between the dosing regimens. CONCLUSION: In this real-world study in which patients were often switched to EI dosing after initial SI therapy, safety and efficacy of EI dosing were maintained in patients with breast cancer. As more patients are treated with EI dosing, this data provides new evidence that switching to EI dosing is safe and effective, while improving medication burden for patients.

Source: The Oncologist

DOI: 10.1093/oncolo/oyaf371