Most Live Bacterial Products have an activity in vivo that is difficult to measure in an in vitro test. Depending on the nature of the LBP, a simple CFU count can be used as a potency assay, but if specific genes are inserted that are supposed to perform a specific activity, or if an activity of the LBP is known a test can be developed to verify that this activity is intact in the Drug Product. This circumvents showing the overall effect of the LBP in an animal model since the reproducibility and discerning power of an animal model is generally low. It remains to be seen if these characterization tests need to become release tests for GMP material, but these tests can be vital to support an IND or IMPD submission.
