Product-specific validation of a serological potency test for release of Leptospira vaccines in the European Union.

Historically in the European Union, all Leptospira vaccines were released using the European Pharmacopoeia (Ph. Eur.) hamster potency assay. Recently, there has been a shift toward alternatives that offer either refinement of testing or replacement of animals for product release. This is being driven by animal welfare concerns but also by a drive to have more consistent, cheaper, and faster batch release tests. This publication discusses one such example of a multicomponent canine vaccine that includes three Leptospira serovars and has recently been registered in the European Union. The potency release test is a refinement because it uses rabbit serology rather than hamster challenge. This publication covers the principles of the test method, challenges faced during its development and registration, and discussion about benefits and limitations of this method. It concludes with a view of how the use of serology testing could fit into an overall strategy to move to fully in vitro testing by adopting a consistency approach.