Using the Analytical Target Profile to Drive the Analytical Method Lifecycle

Quality by design (ICH-Topic Q8) requires a prospective summary of the desired quality characteristics of a drug product. This is known as the Quality Target Product Profile (QTPP), which forms the basis for the design and development of the product. An analogous term has been established for analytical procedures called the Analytical Target Profile (ATP). The ATP, in a similar fashion to the QTPP, prospectively summarizes the requirements associated with a measurement on a quality attribute which needs to be met by an analytical procedure. Criteria defined in the ATP relate to the maximum uncertainty associated with the reportable result that is required to maintain acceptable confidence in the quality decision made from the result. The ATP is used to define and assess the fitness of an analytical procedure in the development phase and during all changes across the analytical lifecycle. One or more analytical procedures can meet the requirements of an ATP. The ATP can be applied to any quality attribute across any pharmaceutical modality where an analytical procedure is used to generate a reportable result, and this paper provides examples from three of these modalities: small molecules, oligonucleotides, and vaccines. Some key performance characteristics will be discussed for each ATP, namely specificity, accuracy, and precision, taking into account the expected range of the analyte. The combination of accuracy and precision into a combined uncertainty characteristic is also discussed as a more holistic approach. The use of the ATP concept will help focus attention on the properties of a method which impact quality decisions rather than method descriptions and may enable greater regulatory flexibility across the lifecycle using established conditions based on method performance criteria as proposed in the Step 2 version of ICHQ12. The revision of ICHQ2(R1) and development of the new ICHQ14 guideline (Analytical Procedure Development) will provide a golden opportunity to harmonize the definition of new QbD concepts such as the ATP.