Real-world use of different pembrolizumab regimens (3 weekly versus 6 weekly) in non-small cell lung cancer (NSCLC) patients

Abstract

Background and objectives: Pembrolizumab monotherapy given 3-weekly (3w) (200mg) is approved for the treatment of non-small cell lung cancer (NSCLC). In June 2019, NICE endorsed the 6w regimen (400mg) based on computer modelling data (Lala, Eur J Cancer 2020), which has been used during the COVID-19 pandemic to reduce hospital visits. This study compared immune-related adverse events (irAEs), discontinuation rates, and patient experience of 3w vs 6w patients treated at The Christie NHS Foundation Trust, Manchester, UK. Methodology: Pharmacy records were used to identify NSCLC patients treated with pembrolizumab, 1st, 2nd or 3rd line. IrAEs and discontinuation rates were analysed using Kaplan Meier curves to compare the 3w vs 6w cohorts. A sample of the cohort who received 3w then 6w undertook a questionnaire assessing patient experience. Results: 38 patients received pembrolizumab 6w, and 91 received pembrolizumab 3w, of the 3w, 51 switched to 6w. Baseline characteristics were similar. Any grade irAEs and G1-2 irAEs were significantly higher in the 6w cohort (p=0.006 and p=0.04, respectively). Both cohorts showed low rates of G3-5 irAEs at 6 months, 2.3% vs 14.5%, 3w vs 6w, p=0.3. Discontinuation rates at 6 months due to any irAES, G1-2 irAEs or G3-5 irAEs were insignificant in both cohorts (3w to 6w respectively): 4.5% vs 11.2%, p=0.2; 2.8% vs 8.7%, p=0.4; 2.0% vs 2.5%, p=0.3. Quality of life questionnaires showed stability (60%) or improvement (20%) in the 6w cohort compared to 3w. 90% said their mental health did not differ between regimens. 45% and 40% of patients preferred 6w and 3w respectively, 15% had no preference. Conclusion: NSCLC patients treated with 6w pembrolizumab appear to experience more low-grade irAEs compared to 3w. High-grade irAEs and discontinuation rates due to irAEs were insignificant in both cohorts. Patients preferred the 6w regiment and found it tolerable.