4CPS-015 Role of clinical pharmacist in the optimisation of nirmatrelvir/ritonavir prescription in the emergency department

Abstract

Aim and Objectives To analyse the inflammatory marker platelet/lymphocyte ratio (PLR) as a predictor of efficacy in immunotherapy treatments; to assess whether there is a relationship between PLR value and response to treatment. Material and Methods Retrospective and observational study of patients diagnosed with NSCLC and treated with pembrolizumab in a tertiary hospital, from January 2018 to December 2021. We collected demographic variables (sex and age), ECOG, histology, presence of metastases, PD-L1 expression and previous treatments. Progression-free survival (PFS) and overall survival (OS) were calculated by the Kaplan-Meier method and log-rank as hypothesis testing.; PLR (absolute platelet count/ absolute lymphocyte count) was calculated and PLR=200 was considered the cut-off point. Cox regression test was used to assess the influence of PLR on treatment efficacy. Results Seventy-three patients treated with pembrolizumab (80.8% male, n=59) and median age 65 [83-37] years. Adenocarcinoma histology was 90% (n=66); 40 patients ECOG=0, 31 patients ECOG=1 and 2 patients ECOG=2; 26 patients PD-L1<50%, 19 patients PD-L1>50% and for 28 patients it was unknown; 12 patients CNS metastases and 22 patients had liver/bone metastases. Significant differences were obtained in the group of patients with liver/bone metastases in PFS with median of 6.3 (2.9-9.6) CI 95% vs 17.3 (11.4-23.2) CI 95% months (p=0.03), and in the group of patients with CNS metastases in OS with a median of 9.6 (1.2-17.9) CI 95% vs at 24.9 (18.6-31.2) 95% CI months (p=0.003). Median PFS was 15.6 [10.15-21.1] 95% CI for PLR <200 vs 9. 97 [2.86-17.1] 95% CI months for PLR >200 (p=0.04); median OS was 26.25 [19.87-32.64] 95% CI for PLR <200 vs 11.31 [3.86-18.79] 95% CI months for PLR >200 (p=0.001). Cox regression test: HR=1.001 (p=0.017) for PFS and HR=1.002 (p=0.003) for OS. Conclusion and Relevance PLR and the presence of metastases correlates with PFS and OS. PLR, with a cut-off point =200, appears useful as a prognostic biomarker for patients with NSCLC treated with pembrolizumab; higher PLR values, result in lower PFS and OS (HR>1 in PFS and OS).