7 Expert Strategies to Control Contamination in Cell & Gene Therapy Manufacturing

Simona Guidi, Associate Director, ProPharma

For the June episode of our Ask the Expert video series, Simona Guidi, Associate Director, Cell and Gene Therapies at ProPharma, discussed the options available for controlling adventitious contamination in cell processing and the use of closed processing systems for cell therapy production. Here, we summarize seven key points she made during the episode:

1. Prioritize Staff Training to Reduce Contamination Risk

Operators are the leading source of bacterial and viral contamination. Invest in routine aseptic technique training and deliver hygiene protocols in native languages to ensure comprehension.

2. Normalize and Monitor Operator Flora

Establish nonjudgmental monitoring systems to detect contamination on personnel. Reinforce that bacterial flora is normal, but its transfer to sterile products must be strictly controlled.

3. Enforce Illness-Based Access Restrictions

Institute policies restricting access to cleanroom areas if staff or close contacts have active viral infections, helping to prevent viral contamination.

4. Choose Closed Systems Over Open Processing

Closed systems (e.g., isolators) minimize operator-product interaction and contamination risk. Preferred over Grade A biosafety cabinets in Grade B cleanrooms due to lower exposure.

5. Use Sterile, Endotoxin-Free Single-Use Materials

Eliminate contamination sources by ensuring all product-contact materials are sterile, endotoxin-free, virus-free, and mycoplasma-free. Request proof of contaminant removal from suppliers.

6. Validate Suppliers with GMP-Like Standards

Since most cell therapy manufacturers can’t test all raw materials, rely on trusted suppliers with GMP-grade product lines and validated Certificates of Analysis or Compliance.

7. Leverage Isolators for Enhanced Containment & Cost Efficiency

Isolators offer high-level separation from GMOs, reduce cleanroom costs, and support compliance with EU GMO and GMP regulations—ideal for decentralized or autologous manufacturing models.

*Access the full episode on our sister website PharmTech.com!