Comparative Quantitative Safety Profiles Of Pd-1 And Pd-L1 Checkpoint Inhibitor Monotherapies: A Bayesian Model-Based Meta-Analysis.

e15167 Background: Anti-cancer therapies with immune checkpoint inhibitors (ICIs) are associated with immune-mediated adverse events (imAEs). The objective of this study was to use a Bayesian model-based meta-analysis, to compare safety profiles of PD-1 and PD-L1 checkpoint inhibitor monotherapies. Methods: We performed an exhaustive search through PubMed and TrialTrove databases, ASCO and ESMO abstracts to identify relevant ICI safety data. A Bayesian meta-analysis (BMA) was performed for all-grade and high-grade (Grades 3-4) treatment-related AEs (trAEs) and immune-mediated AEs (imAEs). The analysis was performed for total AEs and individual AEs affecting different organs: dermatological (rash, pruritus), gastrointestinal (diarrhea, colitis), hepatic (AST, ALT), respiratory (pneumonitis), and endocrine (hyperthyroidism, hypothyroidism). Software STAN along with the brms package in R software were used for the BMA. Results: A total of 145 articles were identified, covering 30,737 patients in 153 cohorts treated with anti PD-1 and anti PD-L1 monotherapies. For total all-grade and grade 3&4 trAEs, anti PD-L1 demonstrated lower AE rates vs. anti PD-1 (65% vs. 69% and 12% vs. 16%, respectively). Results were similar for total all-grade and high-grade imAEs (19% vs. 26% and 4% vs. 7%, respectively). The analysis of all-grade individual trAEs showed that anti PD-L1 exhibited lower AE rates vs. anti PD-1 for rash (8% vs. 10.5%), pruritus (9% vs. 12%), diarrhea (8.5% vs. 11%), colitis (1.0% vs. 1.6%), AST (3.0% vs. 5.5%), ALT (3.5% vs. 5.6%), pneumonitis (3.0% vs. 3.9%), hyperthyroidism (0.8% vs. 4.0%) and hypothyroidism (6.0% vs. 8.0%). For grade 3&4 trAEs, differences between anti PD-L1 and anti PD-1 were: 0.6% vs. 1.3% for diarrhea, 0.7% vs. 1.4% for colitis, and 0.9% vs 1.6% for pneumonitis. All-grade imAEs were less frequent for anti PD-L1 vs. anti PD-1 for: rash (6.5% vs. 10%), colitis (1.0% vs. 2.0%), AST (3.5% vs. 3.9%), ALT (2.9% vs. 4.0%), pneumonitis (2.0% vs. 4.0%), hyperthyroidism (2.5% vs. 4.0%) and hypothyroidism (5.5% vs. 9.0%). Similar results were obtained for grade 3&4 imAEs incidences: rash (0.5% vs. 0.9%), diarrhea (0.5% vs. 1.5%), colitis (0.5% vs. 1.1%) and pneumonitis (0.9% vs. 1.4%). Conclusions: Significant differences in trAEs and imAEs rates were shown for anti PD-L1 vs. anti PD-1 monotherapies. Anti PD-L1 demonstrated more favorable safety profiles for total and individual AE rates. Notably, AE rates for pneumonitis and colitis were twice as high for anti PD-1 vs. anti PD-L1 therapies.