Serum-Free Media for ATMP Manufacturing: CHO and HEK293 Side by Side | SeamlessBio
Advanced therapy medicinal products — gene therapies, cell therapies, tissue-engineered products — depend on upstream cell culture processes that are robust, GMP-compliant and scalable. At the centre of most ATMP upstream processes is one of two production platforms: CHO cells for therapeutic proteins and viral vectors used in ex vivo modification, or HEK293 cells for viral vector manufacturing.
Serum-free medium is not optional in either context. It is a regulatory expectation and a manufacturing necessity.
Why ATMP Manufacturing Requires Serum-Free Media
The EMA’s Advanced Therapy Classification and the EU ATMP Regulation (1394/2007) set a high bar for raw material characterisation. Animal-derived materials — FBS chief among them — introduce:
- TSE/BSE risk: requires EDQM TSE certificates and sourcing justification per Ph. Eur. 5.2.8
- Chargenvariabilität: each lot of FBS is biologically different; GMP processes cannot tolerate undefined variability in critical raw materials
- Downstream contamination risk: residual bovine proteins can appear in the final product and require demonstration of clearance
Serum-free, chemically defined media address all three points. Full component characterisation, no animal-derived raw materials, consistent performance lot to lot.
CHO Cells in ATMP Manufacturing
CHO cells appear in two ATMP-adjacent contexts.
1. Therapeutic protein production for ex vivo cell therapy. Cytokines, growth factors and recombinant proteins used to expand or prime cell therapy products (T cells, NK cells, MSCs) are often produced in CHO. These proteins must be manufactured under GMP with full characterisation — serum-free, chemically defined medium is the standard.
2. Viral vector production. Some AAV manufacturing platforms use CHO or CHO-derived cell lines. More commonly, CHO appears in stable producer cell line strategies for large-scale retroviral or lentiviral vector manufacturing — an area of active development.
For CHO-based ATMP upstream processes, the medium requirements are: chemically defined, protein-free preferred, animal-origin-free documentation, ISO 13485 or GMP certification from the supplier.
→ Serum-Free Media for CHO Cells at SeamlessBio
HEK293 Cells in ATMP Manufacturing
HEK293 is the dominant production platform for viral vectors used in ATMP manufacturing:
- AAV vectors for in vivo gene therapy (retinal dystrophies, haemophilia, neuromuscular disease)
- Lentiviral vectors for ex vivo CAR-T and TCR-T cell modification
- Adenoviral vectors for certain vaccine and gene correction platforms
In each case, the regulatory expectation for GMP clinical manufacturing is serum-free, chemically defined medium with full traceability. For Phase I/II, a research-grade chemically defined medium may be acceptable with appropriate bridging studies. For pivotal trials and commercial manufacturing, GMP-grade medium with ISO 13485 documentation is required.
→ Serum-Free Media for HEK293 Cells at SeamlessBio
CHO vs. HEK293 — Side-by-Side Comparison
| CHO | HEK293 | |
|---|---|---|
| Primary ATMP use | Therapeutic protein, some viral vectors | AAV, lentiviral, adenoviral vectors |
| Kulturformat | Suspension (standard) | Adherent (HEK293T/FT) or suspension (HEK293F) |
| Key medium property | Chemically defined, protein-free | Low albumin, transfection-optimised |
| GMP requirement | ISO 13485, full CoA | ISO 13485, full CoA |
| Regulatory designation | AOF preferred | AOF preferred |
| Scale-up path | Stirred-tank bioreactor | Bioreactor (suspension) or multi-layer flask (adherent) |
Choosing the Right Supplier
For ATMP manufacturing, medium selection is a critical quality decision — not a procurement decision. The supplier must provide:
- Full component list with CAS numbers and sourcing documentation
- Animal-origin-free declaration with traceability to raw material level
- GMP-grade production with ISO 13485 certification
- Batch-specific CoA and CoO
- Regulatory support documentation for IND/IMPD filings
SeamlessBio sources and supplies serum-free, chemically defined media for both CHO and HEK293 platforms, with GMP-grade options and full regulatory documentation support for EU and UK ATMP manufacturers.
→ Contact SeamlessBio to discuss medium requirements for your ATMP manufacturing process.
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