Monograph: |
Rabies immunoglobulin
The properties are similar to rabies human immunoglobulin.
RABIES HUMAN IMMUNOGLOBULIN
DESCRIPTION:
Rabies Immune Globulin (Human)- BayRab (TM) treated with solvent/detergent is a
sterile solution of antirabies immune globulin for intramuscular administration;
it contains no preservative. BayRab is prepared by cold ethanol fractionation
from the plasma of donors hyperimmunized with rabies vaccine. The immune
globulin is isolated from solubilized Cohn Fraction II. The Fraction II solution
is adjusted to a final concentration of 0.3% tri-n-butyl phosphate (TNBP) and
0.2% sodium cholate. After the addition of solvent (TNBP) and detergent (sodium
cholate), the solution is heated to 30 deg C and maintained at that temperature
for not less than 6 hours. After the viral inactivation step, the reactants are
removed by precipitation, filtration and finally ultrafiltration and
diafiltration. BayRab is formulated as a 15-18% protein solution at a pH of 6.4-
7.2 in 0.21-0.32 M glycine. BayRab is then incubated in the final container for
21-28 days at 20-27 deg C. The product is standardized against the U.S. Standard
Rabies Immune Globulin to contain an average potency value of 150 IU/mL. The
U.S. unit of potency is equivalent to the international unit (IU) for rabies
antibody.
The removal and inactivation of spiked model enveloped and non-enveloped viruses
during the manufacturing process for BayRab has been validated in laboratory
studies. Human Immunodeficiency Virus, Type 1(HIV-1), was chosen as the relevant
virus for blood products: Bovine Viral Diarrhea Virus (BVDV) was chosen to model
Hepatitis C virus; Pseudorabies virus (PRV) was chosen to model Hepatitis B
virus and the Herpes viruses; and Reo virus type 3 (Reo) was chosen to model
non-enveloped viruses and for its resistance to physical and chemical
inactivation. Significant removal of model enveloped and non- enveloped viruses
is achieved at two steps in the Cohn fractionation process leading to the
collection of Cohn Fraction II: the precipitation and removal of Fraction III in
the processing of Fraction II + IIIW suspension to Effluent III and the
filtration step in the processing of Effluent III and Filtrate III. Significant
inactivation of enveloped viruses is achieved at the time if treatment of
solubilized Cohn Fraction II with TNBP/sodium cholate.
ACTIONS/CLINICAL PHARMACOLOGY:
The usefulness of prophylactic rabies antibody in preventing rabies in man when
administered immediately after exposure was dramatically demonstrated in a group
of persons bitten by a rabid wolf in Iran. (REF. 1,2) Similarly, beneficial
results were later reported from the U.S.S.R. (REF. 3) Studies coordinated by
WHO helped determine the optimal conditions under which antirabies serum of
equine origin and rabies vaccine can be used in man. (REF. 4-7) These studies
showed that serum can interfere to a variable extent with the active immunity
induced by the vaccine, but could be minimized by booster doses of vaccine after
the end of the usual dosage series.
Preparation of rabies immune globulin of human origin with adequate potency was
reported by Cabasso et al. (REF. 8) In carefully controlled clinical studies,
this globulin was used in conjunction with rabies vaccine of duck-embryo origin
(DEV). (REF. 8,9) These studies determined that a human globulin dose of 20
IU/kg of rabies antibody, given simultaneously with the first DEV dose, resulted
in amply detectable levels of passive rabies antibody 24 hours after injection
in all recipients. The injections produced minimal, if any, interference with
the subject's endogenous antibody response to DEV.
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