Background and Importance The use of lamivudine as prophylactic treatment in patients with past hepatitis B virus (HBV) infection and on treatment with drugs considered at high risk of reactivation has been associated with a higher likelihood of reactivation compared to the use of other antivirals.

Aim and Objectives To evaluate the effectiveness of lamivudine in the prophylaxis of HBV reactivation in patients with haematological disease, undergoing immunosuppressive or chemotherapy treatment and presenting positive serology for HBV.

Material and Methods Observational and retrospective study including all haematological patients over 18 years of age who started HBV prophylaxis between January 2018 and December 2020 in a tertiary hospital. Follow-up was performed from the start of treatment until December 2021 to observe whether HBV reactivation occurred.

Electronic medical records were reviewed and the following variables were collected: demographic data (age and sex), haematological diagnosis, immunosuppressive or chemotherapy treatment received, analytical data (HBsAg, HBcAc, HBeAc, HBV DNA, transaminases) and HBV prophylactic treatment.

Results In the study period, 65 patients started HBV prophylaxis, of which 3 patients were excluded due to false positive. Sixty-two patients (33 women) were reviewed, with a median age (range) of 70 years (20-91). Diagnoses were lymphomas (26 patients), monoclonal gammopathies (13), chronic lymphoproliferative syndromes (7), autoimmune diseases (6), acute leukemias (5), chronic myeloproliferative syndromes (4) and bone marrow aplasia (1).

Out of the 62 patients, 60 patients were HBsAg negative and anti-HBc positive at the initial serological control. All of which received lamivudine prophylaxis. The other 2 patients had chronic HBV infection at the start of prophylaxis, with positive HBsAg, positive anti-HBe and undetectable HBV DNA. One of them started prophylaxis with tenofovir, and the other received lamivudine as prophylaxis.

Of the patients who started lamivudine prophylaxis, 60.7% were being treated with drugs considered at high risk of reactivation (rituximab, doxorubicin or idarubicin).

No patient had either clinical reactivation or detectable HBV viral load during the study period. Fourteen patients died during follow-up due to non-HBV causes.

Conclusion and Relevance In our patients, 60.7% of whom received high-risk drugs, no reactivation event occurred. Lamivudine has proven to be effective in the prophylaxis of HBV reactivation in our study population.

Conflict of Interest No conflict of interest