EARLY INTRODUCTION OF SUBCUTANEOUS (S.C.) HEPATITIS B IMMUNOGLOBULIN (HBIg) PROVIDES LP19 : Early introduction of subcutaneous (S.C.) hepatitis B immunoglobulin (HBIg) provides effective prophylaxis for hepatitis B virus (HBV) reinfection after liver transplantation (TX).

Background & Aims. Subcutaneous HBIg (Zutectra®) in maintenance liver transplant patients assures hepatitis B surface antibody (anti-HBs) serum trough level >100 IU/l, the minimum threshold for effective HBV reinfection prophylaxis. Data regarding early s.c. administration of hepatitis B immunoglobulin are lacking. Methods. In a prospective, open-label, single-arm study, HBV DNA-negative patients undergoing liver tx for HBV infection were switched at 8–18 days post-tx from i.v. to s.c. HBIg (500 or 1,000 IU once a week or once every 2 weeks) if they were HBsAg negative at time of switch, and were monitored to month 6 post-tx. All patients received concomitant anti-HBV nucleoside therapy. Self-injection (or by a caregiver) could be started after week 4 if anti-HBs trough level was >100 IU/l and if patients complied with the injection technique. Primary endpoint was failure rate during 6 months, defined as serum anti-HBs ≤100 IU/l or HBV reinfection with serum anti-HBs >100 IU/l. Results. 49 patients were recruited (20 dosed once a week, 29 dosed once every 2 weeks), of whom 47 (95.9%) continued treatment until month 6. By week 14, 47 patients were self-administering (n=35) or being injected by a caregiver (n=12). No treatment failures occurred during the 6-month study treatment period i.e. all patients maintained serum HBs antibody concentrations ≥100 IU/L and remained HBsAg-negative. All patients tested for HBV DNA remained negative (45/45). Mean anti-HBs declined successively to month 6 to a protective titer of 250 IU/l (Figure). No clinical symptoms consistent with HBV reinfection were observed. Only one non-serious adverse event (mild injection site hematoma) was assessed as treatment-related. No serious drug-related adverse events occurred. All 44 patients who completed an end-of-study questionnaire reported that s.c. injection was convenient and were satisfied with s.c. HBIg. Conclusions. Early switch to s.c. HBIg (between days 8–18) after liver tx maintained serum anti-HBs at a level which effectively prevented HBV reinfection in all patients. Treatment was well-tolerated. Self-administration of s.c. HBIG as part of the combination treatment with HBV virostatic therapy appears a successful and convenient strategy for preventing HBV reinfection.