Safety and Efficacy of Subcutaneous Hepatitis B Immunoprophylaxis using “on demand” Approach: A Single Center Experience

Background: HB immunoglobulin(HBIG)administration is the backbone for prophylaxis of HBV re-infection after liver transplantation (LT). Long term effects and efficacy of HBIG are well known only for intravenous(IV)and intramuscular(IM)formulations. Aim: To investigate efficacy,safety and feasibility of “on demand” subcutaneous (SC) administration of the new formulation of HBIG BT088 (Zutectra )LT patients. Materials and Methods: A total of 37 LT patients(9 F, 28 M, mean age 60 7 years)were switched from IV or IM to SC HBIG administration during a period of 2 years from January 2011. The conversion to SC administration occurred at a mean time of 44 months from the LT. They were prospectively enrolled and followed up for at least 48 weeks. The dose of HBIG was initially standardized to 1000 IU/week. After a period of stabilization, patients were offered a”on demand”approach,with a targeted level of serum antiHBs of minimum100UI/L. Results: All patients were HBV-DNA negative at the time of transplantation(5 spontaneously-14%,32 under NUCs -86%). All patients were on a combination prophylaxis with HBIG and NUCs. All patients became rapidly independent for the weekly SC self-injection. The treatment was effective in maintaining trough anti-HBs levels greater than 100 UI/l in all patients. Ninty of patients showed a mean HBsAb titer greater than 155 UI/l. Overall, mean values of HBsAb were 262 UI/l( 118). The mean HBsAb titre prior to switching to SC formulation was 318 124, with a mean monthly injection of 5000 U/L. No drug related side effects or injection site problems were observed. Conclusions: SC HBIG for long term prophylaxis of post LT HBV re-infection has proven to be safe, well-accepted and effective in maintaining the targeted protective anti-HBs levels. Moreover individualization of immuneprophylaxis according to the lowest protective anti-HBs titers is easily applicable with the SC formulation, allowing the exploration of new schedules in order to improve costs while maintaining efficacy.