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

Background:Hepatitis B 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(9F,28M,mean age60±7years)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 1000IU/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(5spontaneously- 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 selfinjection. The treatment was effective in maintaining trough anti- HBs levels greater than 100 UI/l in all patients. 90%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 5000U/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.