Did you miss our recent Biosimilars Roundtables focusing on "Knowledge-based" Biologics Development? If so, you can watch them on demand now, with Roundtable Chair, Dr Fiona Greer in discussion with expert panelists, Dr Andrew Reason and Dr Ash Ramzan.
These two recorded conversations featured three highly experienced experts discussing aspects of “Knowledge-based” Biologics Development (Part 1 and Part 2) and Analytical Method Qualification and Validation. Once the camera stopped rolling Fiona asked Andrew a few more questions about himself and what interests and motivates him.
Andrew is Managing Director and CEO of BioPharmaSpec, with over 25 years of experience in the commercialization of analytical methods for characterizing biopharmaceuticals.
AJR: My Dad was an industrial chemist and worked for BP and British Gas for many years and I used to go with him to his lab on the weekends. That led me to have an interest in chemistry and through school and college I became interested in medicine and in particular, the design of drug products for the targeted treatment of various cancers, which was in its infancy at the time. This led to a degree in Biochemistry and a PhD in characterizing proteins and glycoproteins using mass spectrometry.
AJR: There have been many but I’d say that the most significant over the last 30 years or so have been improvements in the ease of producing high quality data and in the sensitivity and resolution of instrumentation for biopharmaceutical characterization.
For example, the Q-TOF mass spectrometer, a concept invented by BioPharmaSpec’s CSO Prof Howard Morris in the early 90s, has revolutionized peptide mapping and peptide sequencing. This technique enabled us to determine the primary sequence of proteins and glycoproteins in a time efficient manner for the first time and also allows determination of intact molecular weights of proteins and glycoproteins within 0.01% of the actual mass.
AJR: It obviously depends on the type of molecule under examination, but I’d maintain that the core techniques in any comparability assessment are:
| Peptide Mapping | which provides an overall assessment and comparison of the protein backbone and any Post-Translational Modifications (PTMs) |
| Intact molecular weight analysis | which provides the intact molecular weight of the product and also assesses intactness plus the potential for N- or C-terminal truncations |
| Glycosylation profiling | (for glycoproteins) – to provide an overall assessment and comparison of the glycans present on a product |
| Charge profiling | performed usually using imaged capillary IsoElectric Focusing (icIEF) to allow an overall assessment and comparison of the isoforms of a product and provide insight into potential deamidation, sialylation levels for glycoproteins and levels of Heavy Chain C-terminal Lysine for monoclonal antibodies. |
| Secondary and tertiary structure assessment | the technique used for this assessment and comparison depends on the product and the concentration of the active ingredient in the analysis sample, Circular Dichroism (CD) being the most used technique in this context. |
| Aggregation assessment | to provide an overall assessment and comparison of the aggregation profile of the product, usually performed using Size Exclusion Chromatography with Multi-Angle Light Scattering (SEC-MALS). |
Orthogonality is important to provide confidence in the findings and all of the above elements should be assessed using at least two independent techniques with conclusions drawn from a consideration of all the data. As we both know, for any comparability study data, all the structural and physicochemical requirement in ICH Topic Q6B needs to be provided.
AJR: Method qualification is something that needs to be considered during product development, based on the nature of the specific analysis being undertaken and the nature of the methodology being used. For example, qualifications of methods for residual testing and impurities, or other methods used to demonstrate the correct nature of a particular structural feature, may be viewed differently compared to qualifications of structural characterization techniques using mass spectrometry.
There is no hard and fast rule covering when to qualify a method or what methods should be qualified, but the qualification of selected methods early in product development can help to avoid problems with test processes that may be required for use later but which are shown to have features that preclude meeting validation criteria.
In summary, I’d say what is required at the early stage of product development, at the characterization and definition stage, is that methods are fit for purpose and scientifically accurate, such that data derived from these methods are trustworthy and sound. Thus, in biosimilar analysis, the comparative data generated will allow meaningful conclusions to be drawn regarding structural similarities and differences.
