Measuring the potency of a stem cell therapeutic.

The potency of a drug is one of the most important parameters of a therapeutic. Besides providing the basis for manufacturing consistency and product stability, the potency can predict product failure or toxicity due to incorrect potency, provide release criteria, and the dose that will ensure that it can be used as intended. Recently, cellular therapeutics, in particular, stem cell therapy products, have being designated as "drugs" by regulatory agencies if they produce a systemic effect in the patient. Regulatory agencies are becoming increasingly stringent with respect to the manufacture, production, and testing of these products prior to being used in a patient. A clear understanding of what potency is and how it can be measured should help erase the misunderstandings and misconceptions that have accrued within the cellular therapy field. This protocol describes how the potency of hematopoietic stem cell therapy products is determined. The same principles apply to any proliferating stem cell therapeutic product.