Management of hepatitis B virus (HBV) infection in multiple sclerosis patients on disease modifying therapies (DMTs)

Disease-modifying therapies (DMTs) for multiple sclerosis (MS) can increase the risk of hepatitis B virus (HBV) reactivation (HBr), particularly with agents like ocrelizumab and alemtuzumab. However, studies in MS patients treated with DMTs indicate significantly lower reactivation rates compared to those with hematologic malignancies. This review discusses strategies for managing HBV in MS patients, including chronic hepatitis and potential occult HBV infection (pOBI), with a focus on optimizing safety during DMT therapy. All patients with HBV-related hepatitis should be treated with high genetic barrier nucleoside analogues. In chronic HBV infection, anti-HBV prophylaxis is recommended before initiating DMTs associated with high or intermediate HBr risk, ideally with high genetic barrier NAs. For patients with pOBI receiving B-cell–targeting DMTs, those who are HBsAb-negative or have HBsAb titers < 100 mIU/mL may benefit more from antiviral prophylaxis with lamivudine rather than a preemptive approach. Conversely, pOBI patients with HBsAb titers > 100 mIU/mL may follow a preemptive strategy, involving HBV DNA monitoring and starting prophylaxis only if antibody levels drop below the protective threshold. HBV vaccination is highly recommended for all nonimmune MS patients, with vaccine efficacy in MS patients appearing comparable to that of the general population.