Next-Generation Engineered NK Cell Immunotherapy for Ovarian Cancer

Project 2 SUMMARY/ ABSTRACT Ovarian cancer is the second most common gynecologic malignancy and remains the leading cause of gynecologic cancer deaths in the US. Therefore, there is a critical unmet need for new treatment options. Chimeric antigen receptor (CAR) T-cell therapy has led to a paradigm shift in some hematologic cancers, but

efficacy in solid tumors remains limited, partly due to the lack of highly specific targets and immunosuppression in the tumor microenvironment (TME). Moreover, the time and high cost of manufacturing autologous cell products, and the toxicity challenges related to CAR T-cell therapy call for novel products that are universal,

safe, and potent. There is growing interest in using natural killer (NK) cells for CAR engineering since they have an innate ability to kill tumor cells and they are safe in the allogeneic setting. In a first-in-human study, our group showed the safety and efficacy of cord blood (CB)-derived CAR-NK cells targeting CD19 in patients with B-

lymphoid malignancies. This proposal aims to build on this platform to develop the next-generation NK cell therapies for ovarian cancer by enhancing NK cell potency and persistence through optimal co-stimulatory signaling, cytokine armoring and checkpoint inhibition. We have identified TROP2 as a promising therapeutic

target in platinum-resistant ovarian cancer and developed a novel strategy to target TROP2 by genetically modifying CB-NK cells with a retroviral vector that incorporates the genes for (i) the humanized RS7 single chain variable fragment targeting TROP2; (ii) DAP10 as an NK-specific co-stimulatory domain; (iii) IL-15 to support

their survival and proliferation; and (iv) inducible caspase-9 (iC9) as a safety switch (iC9/TROP2CAR/IL-15). Our preliminary data show the efficacy and safety of this approach in vitro and in vivo and support its translation to the clinic. In addition, we have developed a robust strategy to cryopreserve CAR-NK cells, allowing for the

generation of a biobank of off-the-shelf engineered NK cells that could be thawed and infused at bedside, thus reducing cost and increasing accessibility. Finally, we have devised a novel strategy to target the immune metabolic checkpoint CREM to modulate the metabolic fitness and potency of CAR-NK cells in the acidic TME.

We hypothesize that targeting TROP2 with iC9/TROP2CAR/IL-15 NK cells will greatly improve outcomes for platinum-resistant ovarian cancer and that by targeting the metabolic immune checkpoint CREM we can further enhance the fitness and potency of NK cells. We will test our hypothesis in three specific aims: In Aim 1 we will

conduct a Phase I/II clinical trial to test the safety and efficacy of intraperitoneally delivered iC9/TROP2CAR/IL- 15 NK cells in patients with TROP2+ platinum-resistant ovarian cancer (Protocol 2022-0687). In Aim 2 we will apply innovative single-cell proteomic and transcriptomic studies to comprehensively characterize the fate of the

adoptively transferred CAR-NK cells, their interaction with the peritoneal TME, and key mechanisms of efficacy and resistance. In Aim 3 we will perform mechanistic studies to elucidate how CREM deletion enhances the metabolic fitness of CAR-NK cells and pre-IND studies in preparation for the next-generation clinical studies.