Potency assays measure the functional integrity of a biopharmaceutical product and its ability to produce the desired effect. They are used throughout the development lifecycle to determine critical quality attributes (CQAs) and to ensure consistency between manufacturing batches.
In our latest blog, we asked our bioassay and regulatory experts, Erika Kovacs, Alena Nikolskaya, and Jeff Mocny, to share their expert insights into the key considerations when developing a successful potency assay.
Dr Erika Kovacs, Senior Director of Bioassay at our Cambridge, UK site shares…
To me, a successful potency assay has three key attributes, it is MoA-reflective, precise and accurate. My background is in early R&D, in which sector the Cambridge Bioassay team has been operating for the past ten years. Ensuring you have the best MoA reflective functional assay for complex modalities for PoC studies, lead selection and characterization is our bread and butter.
However, it is quite a long journey an assay must take from providing invaluable data at the beginning of the program to being suitable as a potency assay for lot release at later stages. This is where extensive development, optimization, qualification, and validation become key for creating an assay that performs at the desired high level of accuracy and precision. Here we often need to guide our clients, especially when they are used to operating in the early R&D space. It has been an exciting learning experience for my team as well, and we continuously work with our San Diego colleagues, who are experts in assay validation, as they are operating in later-stage manufacturing.
But also, we support our San Diego colleagues, especially when it comes to early development activities and feasibility studies. We have extensive expertise in techniques such as flow cytometry and microscopy, which are not used as readouts for the potency assay itself but are essential for ensuring that the most suitable cell line and model system is chosen. We do not underestimate the challenge of designing a suitable potency assay for complex MoAs and products, so we make sure we do a thorough job assessing various cell types and readouts early on. In my experience, the extra effort you put into finding the most suitable system in the beginning always pays off in the long run.
We always emphasize a progressive potency assay implementation approach, which is focused on phase-appropriate techniques, where we employ simpler and more robust assays such as ELISAs early on, and bring in cell-based assays as needed for later stages. For me, that is the main benefit of partnering with Abzena, you get the right technical support from start to finish.
Associate Director of Analytical Method Development, Dr Alena Nikolskaya from Abzena’s San Diego facility, shares…
At San Diego AMD we develop and optimize MoA-reflective potency assays to ensure that test methods perform as expected upon transfer to the QC laboratory to ensure successful qualification/validation and GMP testing.
Our methodology is to integrate ICH requirements (Q2 Analytical Validation and Q14 Analytical Procedure Development) and USP chapters (1032-Design and Development of Biological Assays, 1033-Biological Assay Validation, 1034-Analysis of Biological Assay).
Our potency assays must be robust and reproducible to demonstrate acceptable method performance. However, there are some specific terms for potency assay characteristics to be included in a validation protocol. For instance, the interpretation of accuracy, precision, and specificity are like those of other analytical assays, but linearity and range are different. For example, potency assay linearity is not a linear concentration-response function, but a linear relationship between predicted and measured relative potencies within verified reportable range (e.g. from 50% to 150%).
Our expertise in data processing and statistical analysis competency allows us to fully comply with EP and USP requirements (111-Design and Analysis of Biological Assays, 1010-Analytical Data Interpretation and Treatment, 1210-Statistical Tools for Procedure Validation, etc.)
We professionally implement SoftMax Pro software, which offers advanced tools for statistically sound data processing, such as outlier analysis, similarity or parallelism assessment, determination of relative potency using various dose-response fits, with special features supporting FDA 21 CFR Part 11 data integrity regulations, while automatically generating GxP compliant reports after planned data collection, eliminating the need to transfer data to a separate statistical program. Our approach was well received by the bioanalysis community at the BEBPA 2024 US Bioanalysis Conference following our presentation titled: “Outlier Analysis for Relative Potency Assays Using SoftMax Pro Function for Rosner Extreme Studentized Deviate Test”.
Potency assays are critical in the development and production of biological drugs and vaccines and are required throughout the entire development lifecycle. It is important to establish productive relationships and have effective communication with our client’s subject matter experts to discuss emerging issues to ensure confidence in the development, as there are various challenges that drug developers must consider helping to create a successful potency assay:
High variability: Biological systems are inherently variable, making it difficult to develop robust and reproducible assays.
Complex mechanisms of action (MoA): Many biological therapies have complex activity mechanisms, which may require not one, but a combination of complementary assays to fully assess product potency.
Time constraints: Some biological responses take up to 96–120 hours to measure, which can make it challenging to assess product potency promptly.
Validation Challenges: Functional assays covering complex mechanisms can be challenging to validate in a manner that meets all regulatory requirements. Different regulatory agencies may have different requirements for potency assays, for example, the FDA requires quantitative functional assays for release, while the EMA may allow surrogate potency assays in some cases.
At Abzena, we have extensive knowledge and experience with a large range of modalities, including antibodies, bioconjugates, ADCs, AOCs, multi-specifics, fusion proteins, and fragments. Our comprehensive analytical capabilities are fully integrated with our development and manufacturing operations to streamline the process for our customers.
Dr Jeffrey Mocny, Vice President of Regulatory Strategy, shares…
A successful potency assay must demonstrate a drug’s fitness in accuracy, precision, specificity, understanding of the linear range and robustness; and has the appropriate system suitability requirements in place to establish control over the assay. From a regulatory perspective, in the US, all biological products that are regulated under section 351 of the Public Health Safety Act must meet safety, purity, and potency requirements as directed for BLA approval; Federal Food, Drug and Cosmetic Act, (FDC Act), (21 U.S.C. 321 ); (21 CFR 601.2).
The FDA guidance for Industry Potency Tests for Cellular and Gene Products recognizes that there are challenges to potency assays, particularly in the CGT area where potency assays should be considered, which can include and be broadly applied to all biologic systems, both early and late phase:
- Starting material variability
- Lot size and limitations around quantities of material to test
- Limited stability data for the product
- Appropriate reference standards
- The potential of multiple active ingredients
- The potential for complexity in the mechanism of action of the product
- In-vivo fate of the product and metabolism
It’s because of these challenges that the FDA offers guidance on flexibility but, all potency assays used for release testing of licensed biological drug products must comply with applicable biologics and CGMP regulations including the following as indicated in (and cited from) the FDA guidance for Industry Potency Tests for Cellular and Gene Products:
A key point to remember in assay development is that it is critical to demonstrate that the assay is suitable for the intended use. ICH Q14 and ICH Q2R2 drive home the idea that the appropriately developed techniques will allow for sufficient resolution for accurate quantitation so that statistical analysis can be applied. Sound assay development should provide proof that variability can be minimized through understanding the assay system, molecule, and the limitations of the techniques.
Critical to assay development is using appropriate reference standards or controls to demonstrate method fitness, including system suitability, and positive and negative controls.
Summary
Developing and validating potency assays is critical to biopharmaceutical advancement, ensuring functional integrity and consistency from early research to final product release. By addressing key challenges such as high variability, complex mechanisms of action, and stringent regulatory requirements, Abzena’s experts can help develop reliable and accurate assays that drive your program forward. At Abzena, we offer comprehensive potency assay development and validation services tailored to each project’s unique needs.
Our collaborative Cambridge and San Diego teams utilize advanced techniques and a progressive implementation approach to deliver precise, and accurate assays. With our extensive expertise across various modalities and commitment to regulatory compliance, we provide high-quality, integrated solutions that help our customers reach their next target inflection point successfully.
Analytics & Bioassays
