Selection, Expansion, and Unique Pretreatment of Allogeneic Human Natural Killer Cells with Anti-CD38 Monoclonal Antibody for Efficient Multiple Myeloma Treatment

Abstract

Cellular immunotherapy is becoming a new pillar in cancer treatment after recent striking results in different clinical trials with chimeric antigen receptor T cells. However, this innovative therapy is not exempt from challenges such as off-tumor toxicity, tumor recurrence in heterogeneous tumors, and affordability. To surpass these limitations, we exploit the unique anti-tumor characteristics of natural killer (NK) cells. In this study, we aimed to obtain a clinically relevant number of allogeneic NK cells derived from peripheral blood (median of 14,050 million cells from a single donor) to target a broad spectrum of solid and liquid tumor types. To boost their anti-tumor activity, we combined allogeneic NK cells with the approved anti-cluster of differentiation 38 (CD-38) monoclonal antibody Daratumumab to obtain a synergistic therapeutic effect against incurable multiple myeloma. The combination therapy was refined with CD16 polymorphism donor selection and uncomplicated novel in vitro pretreatment to avoid undesired fratricide, increasing the in vitro therapeutic effect against the CD-38 positive multiple myeloma cell line by more than 20%. Time-lapse imaging of mice with established human multiple myeloma xenografts revealed that combination therapy of selected and pretreated NK cells with Daratumumab presented tumor volumes 43-fold smaller than control ones. Combination therapy with an allogeneic source of fully functional NK cells could be beneficial in future clinical settings to circumvent monoclonal antibodies’ low therapeutic efficiency due to NK cell dysfunctionality in MM patients.

Balancing the CD38 Expression on Effector and Target Cells in Daratumumab-Mediated NK Cell ADCC against Multiple Myeloma

“…The presence of CD16a, the low-affinity receptor for IgG1 and IgG3, on the surface of NK-cells is crucial for ADCC-dependent cell killing by tumor-targeting mAbs [ 32 ]. Depending on the expansion and culture conditions, this CD16a expression can decrease, but the combined use of expanded NK-cells (from umbilical cord blood or peripheral blood) with daratumumab shows encouraging results in preclinical studies [ 33 , 34 ]. To avoid daratumumab-mediated fratricide, the CD38-gene can be deleted in expanded primary NK cells without affecting their in vivo persistence or the ADCC activity against MM cell lines and primary MM cells [ 26 ].…”

Preclinical scenario of targeting myocardial fibrosis with chimeric antigen receptor (CAR) immunotherapy

“…They form heterodimers with CD94, with the exception of NKG2D, which dimerizes [54]. The expression balance of inhibitory and activating receptors is not constant and depends on the maturation stage of the NK cells [55]. When triggered, NK cells release lytic granules containing perforin, which can form pores in the target cell, and granzymes from the serine protease family, which can induce apoptosis [56].…”

Natural killer cells: Innate immune system as a part of adaptive immunotherapy in hematological malignancies

“…Indeed, the combination of FT538 and daratumumab in the AML cell line with CD38 expression showed improved cytotoxicity ex vivo in the absence of fratricide 99 . The NK cell product can also be pretreated with daratumumab, leaving the final product of NK cells CD38 negative, which results in a higher therapeutic effect against the CD38 positive multiple myeloma cell line by more than 20% 100 . Another modification is a combination of CAR with previously described CIML NK cells.…”