Case study: Validating a virus transport medium for regulatory submission
Scientific challenge
Developing a VTM
A biotechnology company developing a novel virus transport medium (VTM) required experimental evidence demonstrating that infectious virus titres remained stable for up to 72 hours under a range of storage conditions (4°C to room temperature).
The study needed to follow the CLSI M40-A2 guideline while incorporating additional FDA expectations designed to better reflect clinical sampling conditions, including the presence of human mucus.
Before the regulatory study could begin, a pilot phase was required to determine the optimal virus input capable of generating reproducible quantitative readouts under these more complex experimental conditions. Different sources of human mucus and mucus substitutes also needed to be evaluated to identify the most appropriate testing matrix.
Following successful optimisation, the final study was performed under GLP-like conditions to evaluate virus stability across time and temperature.
Virus |
Influenza virus, Respiratory Syncytial Virus (RSV), human coronavirus NL63 |
Project |
Development and validation of an M40-A2-based method for virus transport media (VTM) evaluation |
Assay |
M40-A2; immunofluorescence-based quantification |
Client |
Biotechnology company |
Stage |
Regulatory submission |
Services |
Bespoke assay development, immunofluorescence-based virus quantification, GLP-like study |
Related expertise |
Virus viability assessment, respiratory viruses, assay optimisation, regulatory studies |
Key considerations
Meeting regulatory requirements
The primary challenge was adapting an established testing standard to meet additional regulatory requirements without compromising scientific robustness.
Particular attention was given to:
- maintaining compliance with the M40-A2 protocol,
- incorporating physiologically relevant mucus into the assay design,
- generating reproducible quantitative measurements across multiple respiratory viruses,
- ensuring complete study traceability and documentation suitable for regulatory submission,
- delivering the project within a demanding development timeline.
Our Approach
Built on experience
VRS built on its extensive experience with immunofluorescence-based virus quantification, a readout routinely used across many of our antiviral and virus characterisation assays.
An initial pilot study was designed to define the experimental parameters required for the regulatory phase, including optimisation of virus inoculum, evaluation of different mucus preparations and confirmation that assay performance remained robust under the modified protocol.
Working closely with the client, we also established the documentation, quality control and traceability procedures required to support regulatory submission before the formal study commenced. This preparation enabled the final study to be initiated rapidly while maintaining consistent execution throughout.
Outcome
Supported FDA submission
The optimised assay successfully demonstrated the performance of the virus transport medium under all required storage conditions using influenza virus, RSV and human coronavirus NL63.
The study generated robust, reproducible data suitable for inclusion within the client’s regulatory submission package and was completed within the required project timeline.
In addition to supporting the immediate submission, the project established a validated workflow that could be readily adapted for the evaluation of future virus transport media or similar products.
VRS INSIGHT
Combining expertise with study planning
Regulatory studies often require more than simply following an established protocol. They frequently involve adapting standard methodologies to address additional scientific or regulatory questions while maintaining reproducibility, traceability and compliance.
This project demonstrated the importance of combining strong virology expertise with careful study planning. By shifting the weight of the study to the optimisation stage, VRS was able to reduce project risk, generate robust submission-ready data and deliver a workflow that could be reused for future evaluations of virus transport media.
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