How do continuous, continued and ongoing process verification differ?

Why

The three terms sound alike and are often confused in interviews and in documents. In the FDA's 2011 guidance, continued process verification is Stage 3. It gives ongoing assurance during routine production that the process remains in control, after process design and process qualification.

In EU Annex 15, ongoing process verification plays the same lifecycle role and applies to every product, whatever approach was used for initial validation. Continuous process verification, also in Annex 15 and drawing on ICH Q8, is an alternative way to validate. For products developed by quality by design, where development has shown the control strategy gives a high degree of assurance, the process can be verified by continuously monitoring and evaluating performance, often using process analytical technology and multivariate statistical process control, instead of a traditional set of validation batches.

Each manufacturer must still justify how many batches give assurance. Annex 15 also allows a hybrid approach that combines traditional validation with continuous verification where there is substantial knowledge. In ICH Q8(R2), continuous process verification is likewise described as an alternative approach to process validation.

So a company can validate a QbD product with continuous verification and then still run ongoing or continued verification for the rest of its life. Mixing the terms in a submission can make a reviewer think a lifecycle program is being offered as initial validation.