In Vivo Persistence and Function of Adaptive NK Cell Infusions (FATE-NK100) from CMV Seropositive Haploidentical Related Donors

Abstract

Adoptive transfer of peripheral blood natural killer (NK) cells from related haploidentical donors incubated in IL-2 persist and expand in vivo and induce clinical responses in patients with AML or ovarian cancer. Individuals who have been exposed to human cytomegalovirus (CMV) have a unique subset of adaptive CD57+/NKG2C+ NK cells that are long lived with properties of immunologic memory, potent mediators of antibody dependent cellular cytotoxicity (ADCC), and resistant to tumor suppressive mechanisms. We developed a 7 day culture process (including GSK3b inhibition and IL-15) to produce a purified adaptive NK cell product (FATE-NK100) from CMV seropositive related haploidentical donors. We are testing this product in two phase 1 clinical trials, one for refractory ovarian cancer (NCT03213964) and one for refractory AML (NCT03050216). After intermediate dose Cy/Flu, 4 patients with ovarian cancer have safely received FATE-NK100 cells delivered intraperitoneally with 6 doses of 6 million units of IL-2 given every other day. Ascites samples demonstrate persistence of the donor NK cell product based on flow cytometric analysis of donor vs. recipient HLA on NK cells. At dose cohorts 2 and 3 (maximum), all subjects had intraperitoneal NK cells of donor origin at Day 5-7 (60-90%), persisting at Day 9 (10-40%) and up to 21 days after infusion in one patient. Importantly, functional assays of the in vivo samples from the patients demonstrate high proliferation based on Ki67 and superior function compared to endogenous patient NK cells based on CD107a degranulation and IFNg production when stimulated with K562 (Figure 1). Clinical activity has been observed and the patient with NK persistence at Day 21 had stable disease and was eligible for re-treatment. The in vivo persistence and function of the FATE-NK100 product was maintained after redosing. Similarly, in 4 evaluable patients with AML treated after higher dose Cy/Flu with IV FATE-NK100 and 6 doses of subcutaneous IL-2 6mu, NK cells of donor origin were detected in the peripheral blood at Day 7 (55-100%), persisting up to 28 days in one patient. All patients at dose cohort 2 achieved clearance of their refractory AML at Day 14 (morphologic leukemia free state) and we await enrollment to the 3rd (maximum) dose cohort (3-10\u202f×\u202f107 NC/kg). In summary, adaptive FATE-NK100 cell infusions persist in vivo in both the peritoneum and peripheral blood and exhibit potent functional activity.