Hepatitis B Reactivation With Pembrolizumab, Atezolizumab, And Nivolumab: A Pharmacovigilance Study And Literature Review.

e15127 Background: Chronic Hepatitis B virus (HBV) impacts 257 million people worldwide. Chemo- and immunotherapies may predispose to HBV reactivation (HBVr), which can negatively impact oncologic outcomes. Programmed death (PD) and programmed death ligand (PDL)-1 inhibitors have been implicated in HBVr. The aim of this study is to report HBVr in patients who are treated with PD-1/PD L-1 inhibitors by utilizing the FDA Adverse Events Reporting System (FAERS) and literature review. Methods: This is a retrospective pharmacovigilance study using FAERS. We reviewed cases of HBVr reported in patients treated with pembrolizumab, atezolizumab, and nivolumab from 2016-2019. Signal disproportionality analysis was conducted using a reporting odds ratio (ROR). A systematic review using Ovid MEDLINE(R) was conducted for additional reports of HBVr and associated outcomes. Results: There were 15 cases of HBVr associated with the use of PD1/PDL1 inhibitors on FAERS (ROR 1.2, 95% CI [0.72-1.99]). Only pembrolizumab was shown to a have significant association with HBVr (ROR 2.93, 95% CI [1.57-5.46]) (Table). Moreover, 7 cases of HBVr were reported in the literature, 3 with pembrolizumab and 4 with nivolumab. Median time to diagnosis following initiation of immunotherapy was 12 (5-24) weeks and 8 (3-10.5) weeks for resolution of HBVr. Conclusions: Pembrolizumab was the only agent with a significant association of HBVr. Future institutional studies in both endemic and nonendemic areas are warranted to determine the true incidence and necessity of pretreatment screening for HBV in patients on PD-1/PDL-1 therapy. [Table: see text]