Contributions
Abstract: EP724
Type: E-Poster Presentation
Session title: Gene therapy, cellular immunotherapy and vaccination - Biology & Translational Research
Background
Though the outcome of patients with Multiple myeloma (MM) has significantly improved over the past decade, most of the patients eventually relapse, with a short progression-free survival period. Recent adoptive cellular immunotherapy is becoming a game-changer in cancer treatment after recent breathtaking outcomes in various clinical trials with chimeric antigen receptor T cells. Nevertheless, this novel therapy is not free from challenges such as affordability, tumor recurrence in heterogeneous tumors, and off-tumor toxicity. To overcome these roadblocks, we capitalize on the unique anti-tumor properties of Natural Killer (NK) cells to target MM in combination with approved monoclonal antibody Daratumumab, applying CD16 polymorphism donor selection and straightforward new in vitro pretreatment to bypass undesired fratricide.
Aims
We propose to explore the feasibility of obtaining a clinically relevant amount of allogeneic NK cells derived from peripheral blood (PBNK) and assess their efficacy in combinatorial therapy with approved anti-CD38 monoclonal antibody Daratumumab to treat incurable MM.
Methods
PBNK cells were isolated from three healthy donors using NK cell isolation kit (Miltenyi). Phenotypic and functional analysis of PBNK cells was evaluated by flow cytometry with a defined panel of antibodies. Polymorphism analysis on FcγRIIIA-158 was performed by flow cytometry with the monoclonal antibody 3G8 clone and MEM-154 clone. Bioluminescence imaging was applied to assess the anti-tumor effectivity of PBNK cells alone, and in combination with Daratumumab, targeting the tumor cell lines RPMI and U266 labeled with the constitutive expression of Firefly Luciferase. In vivo studies were performed in mouse models of MM in four different groups: control group without treatment, single-agent treatment group with Daratumumab, single-agent treatment with PBNK cells, and combinatorial treatment group with Daratumumab and PBNK cells.
Results
We obtained a clinically relevant amount of PBNK cells (median of 14,050 million cells from a single donor) after five weeks of expansion in a GMP-grade feeder-free medium. In vitro studies confirmed the multi-tumor target capacity of expanded PBNK cells, achieving a maximum killing capacity in the fourth week of expansion. The increase in killing capacity may be explained, at least in part, by increased expression overtime of the activation receptor NKG2C. Combination of expanded PBNK cells with Daratumumab procures a synergistic therapeutic effect against MM, increasing more than 20% the therapeutic effect against CD-38 positive MM cell line after CD16 polymorphism donor selection and in vitro pretreatment of PBNK cells to avoid fratricide. Mice with human MM xenografts treated with this combination present tumor volumes 43-fold smaller than control ones.
Conclusion
Our in vitro and in vivo findings presented in this study demonstrate the feasibility of using allogeneic PBNK cells combined with Daratumumab for treating MM. Besides, CD16 polymorphism selection in PBNK cells and novel in vitro pretreatment to avoid fratricide procure a significant increase in the therapeutic effect against MM. Our results fully support and justify the continued development of allogeneic PBNK cells for the treatment of MM.
Keyword(s): Monoclonal antibody, Multiple myeloma, Natural killer
Abstract: EP724
Type: E-Poster Presentation
Session title: Gene therapy, cellular immunotherapy and vaccination - Biology & Translational Research
Background
Though the outcome of patients with Multiple myeloma (MM) has significantly improved over the past decade, most of the patients eventually relapse, with a short progression-free survival period. Recent adoptive cellular immunotherapy is becoming a game-changer in cancer treatment after recent breathtaking outcomes in various clinical trials with chimeric antigen receptor T cells. Nevertheless, this novel therapy is not free from challenges such as affordability, tumor recurrence in heterogeneous tumors, and off-tumor toxicity. To overcome these roadblocks, we capitalize on the unique anti-tumor properties of Natural Killer (NK) cells to target MM in combination with approved monoclonal antibody Daratumumab, applying CD16 polymorphism donor selection and straightforward new in vitro pretreatment to bypass undesired fratricide.
Aims
We propose to explore the feasibility of obtaining a clinically relevant amount of allogeneic NK cells derived from peripheral blood (PBNK) and assess their efficacy in combinatorial therapy with approved anti-CD38 monoclonal antibody Daratumumab to treat incurable MM.
Methods
PBNK cells were isolated from three healthy donors using NK cell isolation kit (Miltenyi). Phenotypic and functional analysis of PBNK cells was evaluated by flow cytometry with a defined panel of antibodies. Polymorphism analysis on FcγRIIIA-158 was performed by flow cytometry with the monoclonal antibody 3G8 clone and MEM-154 clone. Bioluminescence imaging was applied to assess the anti-tumor effectivity of PBNK cells alone, and in combination with Daratumumab, targeting the tumor cell lines RPMI and U266 labeled with the constitutive expression of Firefly Luciferase. In vivo studies were performed in mouse models of MM in four different groups: control group without treatment, single-agent treatment group with Daratumumab, single-agent treatment with PBNK cells, and combinatorial treatment group with Daratumumab and PBNK cells.
Results
We obtained a clinically relevant amount of PBNK cells (median of 14,050 million cells from a single donor) after five weeks of expansion in a GMP-grade feeder-free medium. In vitro studies confirmed the multi-tumor target capacity of expanded PBNK cells, achieving a maximum killing capacity in the fourth week of expansion. The increase in killing capacity may be explained, at least in part, by increased expression overtime of the activation receptor NKG2C. Combination of expanded PBNK cells with Daratumumab procures a synergistic therapeutic effect against MM, increasing more than 20% the therapeutic effect against CD-38 positive MM cell line after CD16 polymorphism donor selection and in vitro pretreatment of PBNK cells to avoid fratricide. Mice with human MM xenografts treated with this combination present tumor volumes 43-fold smaller than control ones.
Conclusion
Our in vitro and in vivo findings presented in this study demonstrate the feasibility of using allogeneic PBNK cells combined with Daratumumab for treating MM. Besides, CD16 polymorphism selection in PBNK cells and novel in vitro pretreatment to avoid fratricide procure a significant increase in the therapeutic effect against MM. Our results fully support and justify the continued development of allogeneic PBNK cells for the treatment of MM.
Keyword(s): Monoclonal antibody, Multiple myeloma, Natural killer