During the early phase of product development, a wide range of analytical techniques will be used to characterize all different aspects of the structure the molecule and from the data generated, decisions will be taken about process and product refinements. But what expectation should be placed on the status of the tests themselves? Should they be demonstrated to perform within a certain set of parameters as would be the case for validated release methods? A recent article has dealt with this question in more detail (1), but here are some of the main considerations.
If we consider the stance taken by the regulatory agencies with regard to biosimilar analyses, then the FDA states:“…methods should be scientifically sound, fit for their intended use, and provide results that are reproducible and reliable.” (2).
The EMA states: “Methods used in the characterization studies form an integral part of the quality package and should be appropriately qualified for the purpose of comparability. If applicable, standards and reference materials (e.g. from Ph.Eur., WHO) should be used for method qualification and standardization.” (3)
and the UK MHRA says “Analytical methods need to be sensitive, qualified and sufficiently discriminatory to detect possible differences. Robust data require the application of suitable orthogonal methods.” (4).
From these statements it is clear that there is an expectation that methods used will be fit for purpose but that there is not a need to have release-type levels of controls at this characterization stage (i.e. methods are not required to be validated). This gives flexibility for methods to be optimized for structural characterization purposes whilst at the same time setting up the expectation that these methods will have checks in place to ensure that data obtained can be relied upon. Qualification of relevant methods does allow a measure of the expected experimental range or error and thus can serve to site the data generated in a broader framework of the method’s capabilities.
|Necessity to perform||No absolute necessity but worthwhile to assess methods that may come to be relied upon||Required for methods that will be used for batch release|
|Time of performance||Structural characterization||Associated with clinical phases|
|Required for structural characterization||No absolute requirement||Not required|
|Needed for batch release||Qualification of methods not sufficient for batch release||Yes|
|Performed to GMP||No||Yes|
|Method parameters to be investigated||None specified. Principles of ICH Q2(R1) most beneficial||ICH Q2 (R1)|
Qualifying methods is beneficial in helping us assess the robustness of that particular methodology. This can be useful if the method is going to be taken forward for validation as a release method. Qualification can demonstrate that (hopefully!) the technique can be relied upon at an early stage thus making the validation process safer with no nasty surprises lurking to catch out analysts at a future date, something which could be time consuming and costly to correct if key decisions have already been taken based on data that were subsequently found to be questionable.
Whilst there is no procedural mechanism detailed for any approach to qualification of methods, application of the process as described in the regulatory method validation document ICH Q2(R1) is sensible (5), since that will give as assessment of what have already been identified as key method parameters.
It is also worth pointing out that certain techniques, such as mass spectrometry-based structural analyses, may well have been employed for assessment of a wide range of products meaning that a precise “qualification” may not be appropriate. The use of demonstrated calibration and applied system suitability tests during the course of the analytical runs can serve to demonstrate that generated data are trustworthy and meaningful.
So what methods would figure most highly in a “requiring qualification” list? Extinction coefficient determination is probably top of most lists, since this parameter is used to determine protein concentration which is key in terms of knowing how much material is being used in bioassay analyses and in vivo work and thus determining potency and safety factors for the product.
Other areas to consider are those of impurity analysis (to demonstrate appropriateness of method to assess key impurities with monitored thresholds) as well as methods that assess critical quality attributes (CQAs). An example of this is peptide mapping by on-line LC/ES-MS, which can be used as a tool for detailed structural characterization work and then, with a good understanding of the identity of the individual peaks, stepped back to a relatively simple LC-UV analysis and assessment of a well understood fingerprint chromatogram of the product to monitor batches.
At some point of course, GMP validation of selected methods for batch release will be required. Having performed an initial qualification of the method there should be no nasty surprises for the unwary analyst when it does come to validation. Not only that, and perhaps of more immediate importance, demonstrating method suitability and robustness through qualification can help to strengthen decision making during product and process development.
Please contact our scientists if you would like to discuss method development and qualification for your product.