With increasing numbers of cell and gene therapy products in development and entering commercialization, more and more sponsors are facing a unique set of challenges of developing bioassays for cell and gene therapy products. Developing appropriate bioassays for cell and gene therapy products tends to be significantly more difficult than for conventional biologics due to a number of different factors, including- the difficulty of adequately modelling the clinical mode(s) of action in a simple cellular system; the challenge of defining, assessing suitability and generating sufficient quantity of, reference substances; non-linear or non-sigmoidal dose response relationships in some bioassays; qualitative or only semi-quantitative responses in others; a need for rapid analytical turnaround times in some cases; an evolving understanding of clinical mode(s) of action in some cases, which may require a close interplay between analytical and clinical development; and finally, the challenge of selecting the best bioassay(s) for release and stability testing vs. characterization/comparability testing. This session will focus on case studies and regulatory feedback that we hope will be beneficial to all sponsors faced with the daunting task of developing a comprehensive control strategy for a cell or gene therapy product.
The development of a relative potency assay to support biologic drug products requires significant budget, resources, and time to achieve the desired quality for release testing. Potency assays ensure safe and efficacious products are delivered to patients, and cell-based bioassays require 1) a relevant and permissive cell line, 2) ability to demonstrate the drug’s mechanism of action (MoA), and 3) quantitative end point. Cell line engineering can achieve these requirements and simplify the MoA detection in a reporter gene system. Here we describe a case study where an engineered reporter gene cell line was used to develop and qualify a relative potency assay within Analytical Development. A cross-over study was successfully performed to transition assay platforms during an ongoing Phase I GMP stability study.
Ultragenyx Gene Therapy is focused on advancing AAV-based gene therapies for rare, but serious, genetic diseases. Potency assessment for such advanced therapeutic product is of critical importance, but can also be very challenging. Because a reliable potency assay is required as early as Phase I/II of product development, we have developed a relative potency assay by measuring the expression of transgene specific mRNA after the transductions of appropriate target cells. Assay was miniaturized and multiplexing was implemented to improve assay throughput and performance. This potency assay shows a high level of robustness and throughput, and requires only minor adjustment while modifying it for novel products. This presentation describes how this platform potency assay was developed and successfully adapted for two different gene therapy products.
We share your passion for science. Promega is committed to excellence in cell-based assays and protein characterization tools for biologics - from lead generation to lot release. Our bioassays for ADCC, immune checkpoints and biosimilars, plus our mass spec proteases and reagents, are used widely throughout the industry. Let’s collaborate.
Engineered cellular therapy products are among the more complex of immunotherapeutic modalities because they are living drugs. As such, flow cytometry-based assays have become essential tools to demonstrate biological critical quality attributes such as identity, cell health and fitness, and potency. One of the biggest challenges in designing and executing flow cytometry-based assays is identifying and controlling variability. A poorly controlled and highly variable assay can increase invalid and re-test rates, or worse, cause a manufacturing process to appear out of control or a drug product to appear unstable. Identifying and mitigating sources of variability begins during initial assay design, as part of QbD for method development, and should continue to be a focus through life cycle management. Here, we will discuss expected and unexpected sources of variability and control strategies in flow cytometry-based assays through representative case studies.
The structures and functions of modern biotherapeutics are becoming increasingly complex. A new generation of diverse multi-modal molecules has quickly emerged, where single molecules can bind multiple targets, harbor multiple activities, have combinatorial/synergistic activities, or all of the above. The complexity of multi-modal biotherapeutics brings about new challenges for bioassay development, as well as exciting opportunities for the application of novel assay formats and technologies.
ELISA binding assays are often used as fit-for-purpose potency assays at early stage of product development for monoclonal antibody and bispecific antibody products. However, the development of an ELISA can be very challenging for bispecific antibody given the complexity of the molecule including multiple binding targets and various binding kinetics and affinity. Our study has shown Surface Plasmon Resonance (SPR) technology plays a critical role to support the development of an ELISA for bispecific antibody by determining the binding kinetics, affinity, and avidity to various targets, and suggesting an optimal ELISA assay format. This strategy can also be applied to bioassay development of other complex modalities.