Tenofovir alafenamide for prevention of HBV reactivation in HBsAg-negative, anti–HBc-positive patients undergoing rituximab-based chemotherapy: A multicenter randomized controlled trial

Background and Aims: Immunosuppression can cause hepatitis B virus (HBV) reactivation, leading to severe outcomes in patients with “resolved” HBV infection. This multicenter, randomized, placebo-controlled trial assessed the efficacy of preemptive antiviral therapy in HBsAg-negative, anti–HBc-positive patients receiving rituximab-based chemotherapy for non-Hodgkin lymphoma (NHL). Methods: Patients were randomized 1:1 to tenofovir alafenamide (TAF)/placebo across 3 phases: chemotherapy plus TAF/placebo (phase 1), TAF/placebo post-chemotherapy (phase 2), and follow-up after therapy cessation (phase 3). The primary endpoint was HBsAg reverse seroconversion. HBsAg and ALT were monitored every 3–12 weeks, depending on treatment phase, and HBV DNA was measured post hoc. ClinicalTrials.gov (NCT02186574). Results: Among 42 patients (median age 65.2 years, 52.4% male, 52.4% aggressive lymphoma, 73.8% anti-HBs positive), 20 received TAF and 22 received a placebo. Median ALT was 20.0 U/L (IQR: 15.0–28.0) at baseline. Median follow-up was 69.4 weeks (IQR: 63.7–166), with 6.1 weeks (IQR: 4.7–8.3) between visits. During follow-up, 2 patients in the TAF arm, but none receiving placebo, experienced HBsAg reverse seroconversions: occurring in phase 3 at 62.3 weeks from baseline, and in phase 1 at 20.0 weeks from baseline. Neither patient experienced ALT >2× ULN. HBV DNA >1000 IU/mL was observed in 8 instances among 6 patients, 3 in each arm, with no associated hepatitis. Low-level DNA (<1000 IU/mL) was not indicative of reverse seroconversion, DNA increases, or ALT elevations. Conclusions: The use of preemptive TAF therapy did not reduce the risk of HBsAg reverse seroconversion; however, the findings should be interpreted with caution as the study was underpowered due to slow enrolment leading to early termination. Low-level HBV DNA elevations were not associated with HBV reactivation. Thus, close HBsAg and ALT monitoring are adequate in HBsAg-negative patients undergoing rituximab-based chemotherapy.