The development of innovative viral vector manufacturing processes strongly depends on the availability of accurate and reproducible product characterization assays and release assays. Release tests for viral vector products typically include tests to measure quantity, potency, vector genetic stability, identity, residuals (i.e. host cell DNA, host cell protein and benzonase), and safety.
To determine which parameters are important to monitor during process development and which are important for release, the product needs to be characterized. Most of the techniques and assays that are used for product characterization are performed in-house. Some of these assays are developed to support process development, using representative material, and then validated for release of the final production. Our expert analytical staff covers all aspects from design to implementation and from development to validation of the assays according to ICH guidelines. Some compendial and most biosafety assays are outsourced to our qualified partners. For outsourcing, we can provide support across all areas, including selection of partners, quotation, temperature-controlled shipments, review and reporting in certificates of analysis.
Controlling materials for viral vector production
Proper control must be established over the materials used in construction and manufacturing of viral vectors. The use of animal-derived components is avoided as much as possible, and when unavoidable, must have traceability and testing in place to mitigate any risk of introduction and transfer of extraneous agents in the process. Extensive testing- by PCR for in vitro and in vivo adventitious agents- to confirm the absence of adventitious viruses in master cell banks (MCB) and master virus seeds (MVS) is performed according to ICH Q5A and ICH Q5D guidelines.
Genetic stability testing
Another important parameter in monitoring the production of viral vectors is genetic stability testing. Here, the vector is propagated for a number of passages until or beyond the envisioned stage of commercial manufacturing. Analysis of the transgene region is needed to assure that the proper antigen expression is maintained. Extended propagation of the starting material provides the sensitivity required to detect any recombinants or mutants that have gained a growth advantage over the target vector. PCR detection combined with sequence analysis provides sufficient specificity and sensitivity to detect any variants in the transgene region that might arise. Next generation sequencing technologies can be employed to characterize vector variants that may be present at low frequencies in virus seeds.
Analytical development expertise
We have ample experience in developing and qualifying a broad range of assays, including (q)PCR, cell-based assays (FFA, PFA and TCID50), HPLC, SDS-PAGE, western blot, and ELISA. As such, we deploy a full range of assays required to successfully monitor the development and release of viral vector-based products.