Innovation meets quality: moving cellular therapies at the National Institutes for Health from bench to bedside

Manufacturing of large numbers of patient-specific T cells for adoptive immunotherapy: an approach to improving product safety, composition, and production capacity

We have developed an innovative system for ex vivo processing of patient-specific cell products to produce large numbers of T-lymphocytes in support of phase 2 adoptive immunotherapy trials for hematologic malignancies. Extensive efforts were undertaken to close the cell processing system to improve the safety profile of the process and comply with new federal regulations regarding cell and tissue processing. Our results demonstrate that apheresis products can be processed in a closed system (Cytomate) with similar yields (approximately 4 x 10(9) mononuclear cells/apheresis) and recoveries (approximately 60% of starting mononuclear cells) to manual cell processing. Cells processed with this system could be cryopreserved for up to 5 months without significant loss of recovery or viability. Additionally, we have evaluated the use of gas permeable bags and developed perfusion bioreactor protocols in which T cells can be rapidly produced in excess of 10(10) viable cells per liter of culture. Using similar methods for upfront processing, we have also developed methods for positive selection and ex vivo culture of CD4+ T cells that result in 200 to 800-fold expansion of fresh or cryopreserved samples. T cells produced in these systems were shown to retain activation-induced cytolytic capability and TH1/TH2 cytokine production as a measure of biologic potency. These new methods allow for more efficient production multiple patient-specific products by satisfying the basic tenants of safety and efficacy required for early phase clinical trials of cell products.

Sterility testing of cell therapy products: parallel comparison of automated methods with a CFR-compliant method

BACKGROUND

Automated blood culture systems are not FDA-approved for sterility testing of human cells, tissues, or cellular- or tissue-based products. It was previously demonstrated that BacT/ALERT (bioMérieux) and Bactec (Becton Dickinson) were superior to the manual CFR method described in the general biologics regulations, in rates of detection and time to detection of organisms seeded into mock mononuclear cell products with a variety of background media and antibiotics. In this study, the two automated systems were compared to the CFR method for sterility testing of actual cell therapy products manufactured in our facility.

STUDY DESIGN AND METHODS

Over a 36-month period, in-process and final product samples from all cell therapy products manufactured in our facility were tested for sterility both by the CFR method and by either BacT/ALERT or Bactec. Products were categorized according to collection and processing variables for analysis of results.

RESULTS

For 1617 samples of a broad range of cell therapy products, rates of true-positive tests were comparable for the automated and CFR methods (2.3% vs. 2.1%), but the CFR method had higher rates of false-positive results (7.3% vs. 0.2%). For automated systems, time to detection of organisms was equivalent to, or faster than, the CFR method.

CONCLUSION

Compared to the CFR method, both BacT/ALERT and Bactec are more sensitive, faster in time to detection, less prone to false-positive results, and less labor-intensive. Both of these automated systems are suitable for sterility testing of cell therapy products after site-specific validation has been performed.