Good manufacturing practice production of an off-the-shelf CD34+ progenitor-derived NK cell product with preserved anti-tumor functionality post-infusion in NOD/SCID/IL2Rgnull mice

The adoptive transfer of natural killer (NK) cells represents a promising cancer therapy due to their intrinsic ability to distinguish between malignant and healthy cells in an allogeneic context, enabling off-the-shelf manufacturing possibilities. On demand availability of cryopreserved advanced therapy medicinal products (ATMPs) could promote enrolment in clinical trials and eventually commercialization with repeated dosing possibilities. However, NK cells are considered highly sensitive to cryopreservation-induced defects, including impaired viability, anti-tumor cytotoxicity, and in vivo expansion capacity. Here, we present the GMP-compliant manufacturing of an off-the-shelf NK cell product (RNK001), derived ex vivo from CD34⁺ hematopoietic stem and progenitor cells (HSPCs). To facilitate scalability and reduce hands-on time, the production process was adapted to a G-rex bioreactor, yielding high numbers of a pure CD56⁺CD3^- NK cell product. Cryopreservation of HSPC-NK cells using an optimized freeze-thaw protocol resulted in a consistently high post-thawing viability of mature and differentiated cells. Surviving HSPC-NK cells post-thawing exhibited enhanced proliferative capacity compared to fresh cells in vitro and their persistence in vivo was similar to that of fresh cells when administrated intravenously or intraperitoneally in NOD/SCID/IL2Rg^null mice. Moreover, cryopreserved HSPC-NK cells had robust anti-tumor functionality, efficiently killing tumor spheroids embedded in a 3D collagen matrix and maintaining degranulation and interferon-γ production capacity comparable to fresh cells following in vivo infusion. Together, these findings show the potential of cryopreserved HSPC-NK cells with potent effector functions, allowing the manufacturing of an off-the-shelf therapeutical NK cell product for hematological and solid malignancies.