Gene Therapy

A gene therapy expertise

For more than 20 years, Clean Cells has supported initiatives promoting the emergence of Advanced Therapy medicinal Products (ATMP) and most notably ex vivo and in vivo gene therapy product development.

Our expertise is structured around two main activities: pharmaceutical quality control in compliance with GMP, and cell and virus banking (generation of starting material) to produce gene therapy products.

Quality control testing in compliance with GMP

Our gene therapy quality control service offer allows for the full characterization of starting material, biological intermediaries, harvests, and lots to ensure the highest safety all along the manufacturing process.

Clean Cells’ GMP licence, issued by the French regulatory authorities (ANSM), is coupled with strict validation of tests and assays according to prescriptive guidelines, including those outlined in the ICH Q2R1.

Our experience is rooted in numerous projects established in close collaborations with gene therapy industry leaders.

BSL-2 and BSL-3-graded products and methods are accomodated in our state-of-the-art facility in the scope of the following quality control testing:


  • Biosafety testing
    • Sterility testing according to 2.6.1 or 2.6.27 (BacT/ALERT automated system)
    • Mycoplasma detection via culture, epifluorescence, or qPCR-based method
    • Virus and adventitious contaminants detection and quantification (in vitro, in vivo, TEM) including bovine/porcine contaminants detection and retrovirus detection (PERT) – more than 200 test references
    • Replication competent virus testing (RCL, RCAAV)
  • Identity testing
    • Cell line authentication by QPCR assay
    • Genetic characterization (GCN, VCN)
    • Cytogenetics tools : karyotype studies, G-banding, FISH, etc.
  • Impurities or residues quantification: HCP, residual DNA, BSA/Benzonase, endotoxins assay
  • Tumorigenicity
  • Potency
    • Physical or infectious vector titre determination
    • Cytotoxicity read-out method for CAR-T products

Reach out to our team of specialists to discuss bespoke development and/or validation needs.

The entirety of our assays can be performed in R&D grade (non-GMP).


Manufacturing biological starting material


Clean Cells, as Contract Manufacturing Organization, supports manufacturing needs expressed by gene therapy stakeholders through cell and virus banking capacities. This biological starting material is further employed in biopharm manufacturing to generate vectors used in vivo or ex vivo gene therapy products.

Our GMP environment accommodates banking procedures to produce vectors using plasmids or baculovirus systems.

Our cell and virus culture expertise covers hundreds of different models and is coupled with the experience of partnering with major players of the biopharma industry.

Research cell banks and virus seed stocks can be supplied to sponsors with non-GMP specifications.