Pembrolizumab in Practice: Assessing Safety and Effectiveness Through a Retrospective Frame

Area of Science:

• Oncology
• Immunotherapy
• Pharmacovigilance

Background:

• Immune evasion is a key mechanism in tumor progression.
• Programmed cell death protein 1 (PD-1) inhibitors, like pembrolizumab, modulate T-cell responses to enhance anti-tumor immunity.
• Pembrolizumab has shown efficacy in metastatic non-small-cell lung cancer and other malignancies.

Purpose of the Study:

• To evaluate the clinical effectiveness of pembrolizumab across diverse cancer types over a five-year period.
• To analyze the pattern and characteristics of adverse drug reactions (ADRs) associated with pembrolizumab treatment.

Main Methods:

• Retrospective analysis of 111 patients receiving at least one dose of pembrolizumab between August 2019 and July 2024.
• Data collection included patient demographics, pembrolizumab therapy details, documented adverse events, and treatment response using RECIST criteria.
• Statistical analysis was performed to assess treatment effectiveness and identify factors associated with toxicity.

Main Results:

• Pembrolizumab demonstrated an objective response rate (ORR) of 14.5% and a disease control rate (DCR) of 61.3% across 22 cancer types.
• Breast cancer patients exhibited favorable outcomes, with 33.3% achieving complete/partial response and 55.6% stable disease.
• Adverse events occurred in 80.2% of patients, primarily mild to moderate (Grade 1-2); Grade 3 thrombocytopenia was observed in five patients and successfully managed. Concomitant lenvatinib increased toxicity, particularly thyroid dysfunction (p=0.041). Patients experiencing ADRs showed better clinical outcomes.

Conclusions:

• Pembrolizumab is an effective treatment option for various cancers, offering a meaningful ORR and DCR with a generally manageable safety profile.
• Immune-related adverse events are common but typically mild to moderate; careful monitoring is essential, especially when combined with lenvatinib.
• The occurrence of adverse reactions may correlate with improved clinical outcomes, highlighting the need for personalized treatment strategies and vigilant patient management.