Method for the detection and quantification of viral contamination during the preparation of gene therapy drugs in a hospital pharmacy.

Abstract

The objective of the present study was to develop a method for sampling and detecting an adenovirus-derived gene therapy (GT) vector on isolator worksurfaces. We used a quantitative PCR (q-PCR) to detect the viral genome in standard dilutions of pure GT product and extracts of sampled surfaces. We compared three devices for surface sampling (a cotton compress, a cotton swab and a polyester flocked swab) and performed positive control, negative control and induced contamination tests for each. Our results showed that the GT pure product is detected by the q-PCR assay and is amplified throughout the range of dilutions. The mean difference between the expected and measured number of vector particles in the q-PCR assay was 1.27 log. The numbers of particles in the total extracted volume were 4.66×10⁸ for the polyester swab (7.8% of the initial quantity), 3.82×10⁸ for a cotton compress (6.4%) and 2.88×10⁷ for a cotton swab (4.8%). These initial results suggest that viral monitoring of worksurfaces is feasible and will help us to validate the GT product supply chain.