A case study of development, validation, and acceptance of a non-animal method for assessing human vaccine potency

Hepatitis B vaccine (Engerix B) is a recombinant vaccine containing hepatitis B surface antigen (HBsAg) produced in Saccharomyces cerevisiae. Initially, this vaccine was released using specifications that required an in vivo potency assay in mice. This paper describes the move from the in vivo potency test toward in vitro potency assays: the in vitro Auszyme test (Abbott Laboratories) and the GSK Biologicals in-house test based upon the inhibition enzyme-linked immunosorbent assay (ELISA) principle. The challenges and difficulties during the development and introduction of this in vitro assay are presented from validation studies performed by GSK Biologicals, through regulatory acceptance, to the implementation of the alternative method by the European Directorate for the Quality of Medicines (EDQM) and HealthCare Control Authorities for Official batch release. Based upon our experience introducing an in vitro model for Engerix B potency assay, we offer suggestions to facilitate future introduction of in vitro assays.