Background and importance The risk of reactivation due to hepatitis B virus (HBV), including fatal cases, in patients treated with daratumumab was reported in June 2019. Health authorities recommended HBV screening in patients before initiation of daratumumab and in patients already receiving treatment. Previous autologous stem cell (ASCT), concurrent and/or prior lines of immunosuppressive therapy (IT) and patients from HBV prevalent regions were established as risk factors for reactivation.
Aim and objectives To analyse the level of compliance with the recommendations for the prevention of HBV reactivation and the risk in our hospital.
Material and methods A retrospective observational study was carried out from January 2017 to September 2020 in a tertiary hospital. It included all patients treated with daratumumab. Medical records and serology tests were reviewed from the start of daratumumab treatment. Information was collected from Abucasis, Farmis and Gestlab. Variables collected were: sex, age, diagnosis, daratumumab start date, HBV reactivation risk factors, serology tests, vaccination and hepatitis B (HB) infection.
Results 20 patients were included with a median age of 70±17 years and 60% were men. The main diagnoses were multiple myeloma in 95% and amyloidosis in 5%. Regarding the prevalence of risk factors for HBV reactivation, 20% received previous ASCT, 90% were treated with IT and no patient had lived in a region of high HBV prevalence. 45% of patients started daratumumab treatment before the alert notification. 44% of the patients in this group had a HB serology test prior to the start of treatment. Of the remaining 55%, a serology test was done in one patient after the alert notification. All serology results for HB surface antigen (HBs-Ag) and HB core antibody (anti-HBc) were negative. No patient had HB before, during or after daratumumab treatment. 44% were vaccinated against HB. 55% started daratumumab treatment after the alert notification. Only 55% of patients in this group had a HB serology test prior to the start of treatment. Serology results for HBs-Ag and anti-HBc were negative except for one patient. Complementary tests were carried out resulting in HBV infection in the past. The patient started treatment with tenofovir 15 days before starting daratumumab as prophylactic treatment for HBV reactivation. 9% were vaccinated against HBV prior to daratumumab treatment. No case of HBV reactivation was detected.
Conclusion and relevance Only 65% of patients treated with daratumumab had at least one HBV serology test performed. More serology tests should be carried out to detect patients at risk for HBV reactivation. Any case of reactivation was detected in our hospital.
Conflict of interest No conflict of interest