Prophylactic Antiviral Therapy in Patients With Current or Past Hepatitis B Virus Infection Receiving Anti-Cancer Therapy for Solid Tumors

Co‐Primary Objectives 1. To compare the effect of prophylactic anti‐HBV therapy versus upon indication anti‐HBV therapy on time‐to‐adverse liver outcomes of liver failure or liver‐related death in patients with chronic HBV infection (HBsAg+ and anti‐HBc+) receiving anti‐cancer therapy for solid tumors. 2. To compare the effect of upon indication anti‐HBV therapy versus usual care on time‐to‐adverse liver outcomes of liver failure or liver‐related death in patients with past HBV infection (HBsAg‐ and anti‐HBc+) receiving anti‐cancer therapy for solid tumors. Secondary Objectives 1. Using time‐to‐event analysis, to compare the effect of anti‐HBV therapy versus upon indication anti‐HBV therapy on HBV reactivation, on the combined endpoint of adverse liver outcomes (liver failure or liver‐related death) and HBV reactivation, and on HBV flare by arm in patients with chronic HBV infection receiving anticancer therapy for solid tumors. 2. Using time‐to‐event analysis, to compare the effect of upon indication anti‐HBV therapy versus usual care on HBV reactivation, on the combined endpoint of adverse liver outcomes (liver failure or liver‐related death) and HBV reactivation, and on HBV flare by arm in patients with past HBV infection receiving anti‐cancer therapy for solid tumors. Translational Objectives 1. To compare baseline and changes in overall immune status and HBV‐specific immune response in patients with solid tumors and chronic or past HBV infection receiving anti‐cancer therapy, and to compare the differences in these immune responses by HBV reactivation status. 2. To identify demographic and clinical predictors and correlative immunologic biomarkers of HBV reactivation after receipt of anti‐cancer therapy in patients with solid tumors and chronic or past HBV infection. OUTLINE: Patients are recruited in two cohorts (Cohort 1: chronic HBV infection, Cohort 2: past HBV infection), with each cohort randomized equally to one of two potential treatment arms. Chronic HBV Infection (Cohort 1) Arms: Arm 1: Patients receive tenofovir alafenamide (TAF) orally (PO) once daily (QD) or tenofovir disoproxil fumarate (TDF) PO QD or entecavir PO QD immediately or within 42 days after initial dose of chemotherapy. Treatment continues for up to 6 months after the last dose of chemotherapy or a maximum of 24 months in the absence of disease progression or unacceptable toxicity. Arm 2: Patients receive TAF PO QD or TDF PO QD or entecavir PO QD after HBV reactivation during chemotherapy. Treatment continues for up to 6 months after the last dose of chemotherapy or a maximum of 24 months in the absence of disease progression or unacceptable toxicity. Past HBV infection (Cohort 2) Arms: Arm 3: Patients receive TAF PO QD or TDF PO QD or entecavir PO QD after HBV reactivation during chemotherapy. Treatment continues for up to 6 months after the last dose of chemotherapy or a maximum of 24 months in the absence of disease progression or unacceptable toxicity. Arm 4: Patients receive anti‐HBV therapy at the discretion of the physician. Any Food and Drug Administration (FDA) approved anti‐viral medication for HBV may be used. (Cohort 1: Arm 2 and Cohort 2: Arm 3 follow the same treatment plan, but are considered part of separate parallel studies and are therefore identified as separate arms.) Patients are followed for 24 months: every 4 weeks from randomization to week 24, then every 8 weeks thereafter up to week 104.