Cytokines induced killer cells produced in good manufacturing practices conditions: identification of the most advantageous and safest expansion method in terms of viability, cellular growth and identity

BACKGROUND: Cytokine-induced killer (CIK) cells are a very promising cell population raising growing interest in the field of cellular antitumor therapy. The aim of our study was to validate the most advantageous expansion method for this advanced therapy medicinal product (ATMP) and to translate it from preclinical field to good manufacturing practices (GMP). GMP ensures that ATMP are consistently produced and controlled to the quality standards required to their intended use. For this reason, the use of the xenogenic sera tended to be minimized by GMP for their high variability and the associated risk of transmitting infectious agents. RESULTS: We decided to replace Fetal Bovine Serum (FBS), largely used as medium supplement for CIKs expansion, with other culture media. Firstly, Human Serum (HS) and Human Pool Plasma (HPP) were tested as medium supplements giving not compliant results to acceptance criteria, established for CIKs, probably for the great batch to batch variability. Consequently, we decided to test three different serum free expansion media: X-VIVO 15, (largely used by other groups) and Tex Macs and Cell Genix GMP SCGM: two GMP manufactured media. We performed a validation consisting in three run-sand even if the small number of experiments didn’t permit us to obtained statistical results we demonstrated that both X-VIVO 15 and Tex Macs fulfilled the quality standards in terms of cellular growth, viability and identity while Cell Genix GMP SCGM resulted not compliant as it caused some technical problems such as high mortality. CONCLUSION: In conclusion, these preclinical validation data lay the bases for a GMP-compliant process to improve the CIKs expansion method.