Background  Reactivation of hepatitis B virus infection in asymptomatic hepatitis B surface antigen carriers undergoing chemotherapy or immunosuppressive therapy is a well-documented and potentially fatal complication. Data supporting the use of lamivudine for primary prophylaxis have emerged, but its use remains controversial and is not standardized.

Aim  To review current randomized-controlled trials, randomized trials and prospective case series to provide a clinically applicable, evidence-based recommendation.

Methods  The published literature was identified using a MEDLINE/PubMed search with secondary review of cited publications, and inclusion of all prospective studies.

Results  In nine prospective trials and one randomized-controlled trial, the rate of hepatitis among subjects receiving lamivudine prophylaxis ranged from 0% to 20% (16 of 173, 9.2%), compared with 33–67% among controls. Of patients receiving prophylaxis, 0–24% (15 of 173, 8.7%) developed hepatitis B virus reactivation, compared with 29–56% of controls. Three reactivation-related mortalities were reported (one receiving prophylaxis, two controls). No patients withdrew secondary to toxicity or development of lamivudine-resistant mutations.

Conclusions  The available data show a four- to sevenfold decrease in the rate of hepatitis and hepatitis B virus reactivation in patients who receive lamivudine prophylaxis. It is thus recommended that all hepatitis B surface antigen carriers receive lamivudine, or a comparable anti-viral agent, as prophylaxis from the initiation of chemotherapy until at least 1 year following its completion.