The base of curing for many diseases: Cell and Gene Therapy Manufacturing

What critical manufacturing factors are influencing the success of Cell and Gene therapy developments

Cell and Gene Therapies (CGT) demand a highly controlled manufacturing process.

Cell and Gene Therapies (CGT) represent a groundbreaking advancement in modern medicine, offering curative potential for genetic disorders, cancer, and degenerative diseases. These therapies utilize engineered cells or genetic modifications to treat or replace damaged tissues and defective genes. While cell therapy involves the transplantation of live cells to restore function, gene therapy modifies or replaces faulty genes to correct diseases at the molecular level. Both approaches demand highly controlled manufacturing processes to ensure safety, efficacy, and scalability.

What are Cell and Gene Therapies?

Cell therapy involves the administration of living cells into a patient to repair or replace damaged tissue. These cells may originate from the patient (autologous therapy) or a donor (allogeneic therapy). The most common cell therapy applications include

• stem cell therapies, such as hematopoietic stem cell transplantation for leukemia treatment

• T-cell therapies e.g., CAR-T cell therapy for cancer immunotherapy

• regenerative medicine approaches e.g., mesenchymal stem cells for cartilage repair

  
  

Gene therapy aims to correct genetic defects, such as repetitive gene sequences causing deformed proteins by delivering functional genetic material into a patient's cells. It is used to treat hereditary diseases, cancer, and acquired disorders. Gene therapies can be split into in vivo gene therapy, where the genetic material is directly delivered into the patient’s body using viral or non-viral vectors. An example of this application is Zolgensma, an adeno-associated virus (rAAV) vector-based therapy for the treatment of skeletal muscle atrophy caused by a dysfunctional SMN1 gene of the SMN protein in motor neuron cells. Ex-vivo gene therapy, also known as gene-modified cell therapy, involves modifying the patient’s cells outside the body and reintroducing into the body. Genetically engineered cells such as chimeric antigen receptor T cells (CAR-Ts) are leading the trial landscape for treating several cancer types and are in development for autologous and allogenic use (1).

How are Cell and Gene Therapies manufactured

Manufacturing Cell and Gene Therapies is a complex, multi-step process that requires strict regulatory oversight and highly controlled conditions. As the industry is growing rapidly, with over a thousand active trials in 2020 (2), and nearly 2,000 active trials in 2024, the demand for manufacturing capacity is increasing. The basis of the therapies is cells, which usually involve either stem cells (MSCs, iPSCs, HSCs) or somatic cells.

Major steps for manufacturing Cell and Gene Therapy are (3-4):

1. Cell Sourcing & Collection

   • Autologous therapies require patient-specific cell extraction.

   • Allogeneic therapies involve large-scale donor cell banking.

     
     

2. Cell Isolation & Expansion

   • Culturing and expanding cells under Good Manufacturing Practice (GMP) conditions.

   • Maintaining sterility, preventing contamination and unwanted differentiation, while providing optimal growth conditions for vitality and viability

     
     

3. Genetic Modification (if applicable)

   • Utilizing viral vectors (e.g., lentivirus, AAV) or CRISPR-based gene editing.

   • Ensuring precise gene insertion with minimal off-target effects.

   • In some cases, the modification is introduced before expansion

     
     

4. Cell Processing & Differentiation

   • Inducing differentiation for specialized cell types (e.g., T cells, stem cells).

   • Monitoring phenotype stability and therapeutic efficacy.

     
     

5. Formulation & Cryopreservation

   • After a sample for QA is taken, Cells are prepared for storage, transport, and clinical administration.

   • Cryopreservation protocols ensure cell viability upon thawing.

     
     

6. Quality Control & Regulatory Compliance

   • Ensuring sterility, identity, and potency through rigorous testing.

   • Adhering to FDA, EMA, and other regulatory standards for CGT manufacturing.

     
     

After the manufacturing of the therapy, the application to patients takes place. Depending on the type of therapy, either cells are introduced or formulated vectors transferring the genetic modification.

Cell culture manufacturing factors for Cell and Gene Therapy manufacturing

Successful cell therapy manufacturing depends on optimizing cell culture conditions to maintain cell viability, potency, and functionality. For the efficacy of the cell therapy in an in vivo setting, the modified cells must remain functional (3-4). Many of these factors are highly influenced by the cultivation and expansion of the initial cell culture, making cultivation systems one of the key factors for therapy manufacturing success (4-5).

Critical factors for therapy manufacturing and application success include:

1. Cell Source & Quality

• The origin and health of the starting material impact overall therapy success.

• Genetic stability and purity are essential for reproducibility.

  
  

2. Bioreactor Systems & Culture Methods

• Adherent vs. suspension cultures – Stem cells often require specialized surfaces, while T cells thrive in suspension.

• Scalability considerations – Traditional flasks vs. closed-system bioreactors.

  
  

3. Media & Nutrient Supply

• Optimized cell culture media formulations are needed for expansion and differentiation.

• Serum-free and xeno-free media are preferred for clinical applications to avoid variability.

  
  

4. Oxygenation & Environmental Control

• Hypoxic conditions can influence cell growth.

• Real-time monitoring of pH, temperature, and gas exchange ensures consistency.

  
  

5. Genetic Stability & Functional Integrity

• Long-term expansion can introduce mutations or epigenetic changes.

• Quality control assays validate functional attributes before clinical use.

  
  

6. Contamination Prevention & Closed System Processing

• CGT manufacturing follows strict aseptic techniques to minimize microbial risks.

• Implementing automation and closed bioprocessing systems improves reproducibility.

Cell and Gene Therapy manufacturing involves several process steps resulting in an applicable therapy. The key factors for a successful therapy are cell quality, cell identity, and reproducibility.

Cell and Gene Therapies represent a new era in medicine, offering curative treatment options for previously untreatable diseases. Their production requires advanced cell therapy manufacturing techniques, precise genetic modifications, and strict quality control. Optimizing cultivation conditions—from bioreactor selection to contamination control—is crucial to ensuring their success. While the environment in which the cells are grown influences the success of the therapy for the patient, the scalability and reproducibility of their manufacture directly impact the financial viability and access to the therapy. As the field evolves, scalable, automated, and cost-effective solutions will be key to making these transformative therapies more widely accessible.

References

1. Chancellor D et al., The state of cell and gene therapy in 2023, Molecular Therapy, Volume 31, Issue 12, 3376 - 3388

2. Lambert J, “Alliance of Regenerative Medicine 2021 Cell and Gene State of the Industry briefing,” Alliance of Regenerative Medicine, 2021, available from http://alliancerm.org/wp-content/uploads/2021/01/SOTI-2021-pdf.pdf.

3. Wang LL, Janes ME, Kumbhojkar N, Kapate N, Clegg JR, Prakash S, Heavey MK, Zhao Z, Anselmo AC, Mitragotri S. Cell therapies in the clinic. Bioeng Transl Med. 2021 Feb 26;6(2):e10214. doi: 10.1002/btm2.10214. PMID: 34027097; PMCID: PMC8126820.

4. Iyer RK, Bowles PA, Kim H, Dulgar‐Tulloch A. Industrializing autologous adoptive immunotherapies: manufacturing advances and challenges. Front Med. 2018; 5:150‐150.

5. Eaker S, Armant M, Brandwein H, Burger S, Campbell A, Carpenito C, Clarke D, Fong T, Karnieli O, Niss K, Van't Hof W, Wagey R. Concise review: guidance in developing commercializable autologous/patient-specific cell therapy manufacturing. Stem Cells Transl Med. 2013 Nov;2(11):871-83. doi: 10.5966/sctm.2013-0050. Epub 2013 Oct 7. PMID: 24101671; PMCID: PMC3808202.