THE ROLE OF PREVALIDATION IN THE DEVELOPMENT, VALIDATION AND ACCEPTANCE OF ALTERNATIVE METHODS

Experience has shown that the outcome of large and expensive validatio n studies on alternative methods can be compromised if their managers do not insist that optimised test protocols and proof of their perform ance are submitted before the start of the formal validation study. On e way for the sponsors of validation studies to confirm both the likel y relevance of a method for its stated purpose and its readiness for v alidation would be to require a prevalidation study before formal vali dation was contemplated. This process would involve the developers (or other proponents of the method) and selected independent laboratories in protocol refinement (Phase I) and protocol transfer (Phase II). Th e optimised protocol would then be assessed in a protocol performance phase (Phase III), which would involve the testing of a relevant set o f coded test materials and an evaluation of a proposed prediction mode l. In certain circumstances, a successful outcome of Phase III might b e sufficient for promotion of the regulatory acceptance of the method. Normally, however, the method would proceed to a formal validation st udy. The European Centre for the Validation of Alternative Methods, a recognised validation authority, now proposes to introduce this preval idation scheme into its validation strategy.