Antiviral prophylaxis for patients undergoing cancer chemotherapy or immunosuppression

Patients who are hepatitis B surface antigen (HBsAg) positive

All patients who test positive for hepatitis B surface antigen (HBsAg) and who will be receiving significant immunosuppressive therapy should begin antiviral prophylaxis with tenofovir or entecavir, ideally at least 1 week before starting therapy, although urgent chemotherapy or immunosuppression should not be delayed. The antiviral dosage regimens for prophylaxis are the same as those recommended for treatment—see Antiviral treatment regimens for chronic hepatitis B infection.

Antiviral prophylaxis should generally be continued for at least 12 months after stopping immunosuppressive therapy. If B-cell depleting, B-cell active or anti-CD20 drugs (eg rituximab) are part of the immunosuppressive regimen, or if the patient is undergoing haematopoietic stem cell transplantation, prophylaxis should continue for at least 18 to 24 months after stopping immunosuppressive therapy because late reactivation of hepatitis B (longer than 12 months after completing rituximab therapy) has been reported.Doyle 2019Australian hepatitis B consensus statement 2022

Patients who are hepatitis B surface antigen (HBsAg) negative and hepatitis B core antibody (anti-HBc) positive

The risk of hepatitis B reactivation in patients who are hepatitis B surface antigen (HBsAg) negative and hepatitis B core antibody (anti-HBc) positive varies depending on the type of chemotherapy they receive.

Patients who receive B-cell depleting, B-cell active or anti-CD20 therapy, or who undergo haematopoietic stem cell transplantation or treatment for acute leukaemia or high-grade lymphoma, are at higher risk of hepatitis B reactivation and antiviral prophylaxis is recommended. The antiviral dosage regimens for prophylaxis are the same as those recommended for treatment—see Antiviral treatment regimens for chronic hepatitis B infection. The optimal duration of antiviral prophylaxis in this setting is unclear, but as is the case for HBsAg positive patients, it should be continued for at least 18 to 24 months after completion of B-cell depleting, B-cell active or anti-CD20 therapy or haematopoietic stem cell transplantation.Doyle 2019Australian hepatitis B consensus statement 2022

Patients receiving other forms of chemotherapy are at low risk of hepatitis B reactivation and do not require antiviral prophylaxis. They should be monitored and hepatitis B reactivation considered if there is an unexplained elevation in alanine aminotransferase (ALT) concentration.