Pharmacokinetics and efficacy of intravenous or intramuscular hepatitis B immunoglobulins in prophylaxis of hepatitis B after liver transplantation.

AIM: The use of hepatitis B immunoglobulin (HBIg) combined with nucleos(t)ide analogues (NUCs) has improved outcomes in post-hepatitis B (PHB) liver transplant (LT), reducing the 1-year recurrence rate below 10%. The aim of this study was to evaluate efficacy and pharmacokinetics of prophylaxis with NUC(s) and intravenous (iv-) or intramuscular (im-) HBIg in 33 PHBLTs, transplanted for more than 1 year. METHODS: During the first six months of the study, 18 subjects received 5000 IU of iv-HBIg every four weeks and 15 patients 2160 IU/12 mL of im-HBIg every two weeks. In the following six months, 31 subjects were switched to two different concentrations of im-HBIg, 2160/12 mL (16 patients) or 2000 IU/6 mL every two weeks (15 patients). RESULTS: All patients remained HBsAg-negative and 30/31 maintained anti-HBs >100 IU/L. Overall mean anti-HBs titer during treatment was 363 IU/mL. Mean HBIg half-life was 21.4, 27.3 and 26 days with intravenous, diluted or concentrated im-preparations, respectively. CONCLUSION: These results confirm an analogue efficacy and tolerance of iv- and im-HBIg combined with antivirals in prophylaxis of hepatitis B after LT. Anti-HBs titers three times higher than aimed and four weeks mean half-life could suggest the reduction of doses and the elongation of the interval of administration of im-HBIg.