Hepatitis B virus reactivation associated with Janus kinase (JAK) inhibitors: a retrospective study of pharmacovigilance databases and review of the literature

Recently, there have been clinical reports of hepatitis B virus reactivation (HBVr) related with Janus kinase (JAK) inhibitors. However, there were no studies to investigate the association between HBVr and different JAK inhibitors.This study was a retrospective review utilizing the FAERS pharmacovigilance database and a systematic literature search for all cases of HBVr reported with JAK inhibitors. Disproportionality analysis and Bayesian analysis were used in data detection to screen the suspected HBVr after the administration of different JAK inhibitors, based on the FDA Adverse Event Reporting System (FAERS) pharmacovigilance database from Q4 2011 to Q1 2022.There were a total number of 2097 (0.02%) reports of HBVr in FAERS, of which 41 (1.96%) were associated with JAK inhibitors. Baricitinib appeared to have the strongest signal among four JAK inhibitors, based on the highest reporting odds ratio (ROR = 4.45, 95% confidence interval [CI] 1.67-11.89). Ruxolitinib also showed signals, whereas no signals were detected among Tofacitinib and Upadacitinib.While there may be an association between JAK inhibitors and HBVr, it appears to be a numerically uncommon occurrence. Further studies are needed to optimize the safety profiles of JAK inhibitors.