Manager PPD, part of Thermo Fisher Scientific Richmond, Virginia
Enzymatic activity assays conducted in support of long-term cell and gene therapy clinical trials can vary in cost, complexity and performance due to reagent performance and handling as well as reagent and sample stability. These challenges are difficult to resolve without the availability of an enzymatic reference standard. In addition, assay complexity as well as enzyme stability in matrix make traditional strategies for proving assay reproducibility problematic.
To ensure continuity in enzymatic activity data over time, bulk reagents and bulk 4-Methylumbelliferone calibration standards were prepared and qualified in the presence of freshly prepared calibration standards and quality controls (QCs) of known performance. The bulk materials were then stored at nominal -80°C for long-term use to reduce variability during periodic enzymatic activity measurements. Feasibility testing of frozen 4-MU calibrators was initiated to overcome variation in daily preparations attributed to analyst technique differences, diluent pH differences and 4-MU handling/stability as well as lot-to-lot variation. Due to lack of proven long-term storage stability of critical and non-critical reagents, assay performance was monitored by trending assay performance indicators over time such as instrument responses and back-calculated activity of pre-screened, frozen endogenous QCs as well as freshly prepared recombinant enzyme QCs. Frozen curve instrument responses were also measured over time to evaluate changes in calibrators relative to performance observed upon initial qualification. To confirm the trending strategy of 4-MU in frozen diluent, low and high calibrator points were stored long-term at nominal -80°C, then tested against fresh 4MU calibrators. These results will be discussed to provide generalized approaches and considerations for long-term data continuity between patients and their respective time points.
Learning Objectives:
Upon completion, participants will learn strategies to reduce enzyme activity assay and reagent handling variability for long-term cell and gene therapy studies.
Upon completion, participants will learn strategies to monitor long-term enzyme activity assay performance to ensure continuity and minimize variability over the course of long cell and gene therapy clinical studies.
Upon completion, participants will learn how to justify reagent retest extension to minimize variation that might be caused by introduction of new reagents that may have different activity or performance.