Analytical data had revealed that intramuscular immunoglobulin (IGIM) may yield decreased protection against hepatitis A virus (HAV) infection, thus prompting an update in the recommended IGIM dose (0.2 ml/kg).

A prospective, open-label, single-arm clinical study was thus conducted to determine if a single 0.2 ml/kg dose of IGIM yielded protective levels of anti-HAV antibodies (≥ 10 mIU/ml for up to 60 days) in HAV-seronegative healthy adults.

Twenty eight subjects were enrolled and dosed. Of these, 26 (93%) completed the study. Mean uncorrected anti-HAV antibody titers peaked at 109 mIU/ml on day 5 and continued to remain above 10 mIU/ml through day 60. Mean uncorrected anti-HAV antibody titers had a median T_max of 95.33 h, a mean C_max of 118 mIU/ml, and a mean observed T_half of 63.3 days. It was noted that the baseline-corrected titers had a median T_max of 95.33 h, a mean C_max of 114 mIU/ml, and a mean observed T_half of 47.1 days (N = 27). All the participants (28/28) had at least 1 treatment-emergent adverse event (TEAE), with a total of 83 TEAEs, none being serious; 96% (80/83) resolved without sequelae.

Most (63%) events that were considered definitely and possibly related to study treatment involved localized pain due to intramuscular injections. There were no serious adverse events and no deaths or discontinuations due to TEAEs.

Investigators came to the conclusion that a single 0.2 ml/kg dose of IGIM yielded protective anti-HAV levels for at least 60 days, with an acceptable safety and tolerability profile in healthy subjects. Uncorrected and baseline-corrected pharmacokinetics were found to be similar and consistent with the corresponding sampling points in previous research.

Source: Kankam M, Griffin R, Price J, et al. Polyvalent Human Immune Globulin: A Prospective, Open-Label Study Assessing Anti-Hepatitis A Virus (HAV) Antibody Levels, Pharmacokinetics, and Safety in HAV-Seronegative Healthy Subjects. Adv Ther. 2020 May;37(5):2373-2389.