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170 Background: CRC is the 4th leading cause of global cancer-related deaths, and novel therapeutic strategies for advanced CRC are urgently needed. Adoptive cell therapy (ACT) is effective in treating hematological malignancies; however, ACT in solid tumors is hindered by target antigen identification, restricted migration into tumors, and survival in the tumor microenvironment (TME) due to immunosuppressive signals and scarcity of nutrients. NK cells are central to anti-tumor immunity and can directly eliminate tumor cells without prior sensitization. Through cytokine reprogramming, NK cells can also gain memory-like features that augment their anti-tumor potential. WU-NK-101 is a cytokine-reprogrammed, expanded, cryopreserved, off-the-shelf NK cell product derived from peripheral blood mononuclear cells, with no additional engineering. Methods: WU-NK-101 ± Ctx was evaluated in vitro in 2D cytotoxicity assays in complete (N) and TME-aligned medias. WU-NK-101 cytotoxicity was further assessed against primary CRC surgical samples in native-TME-aligned 3D assays. Proteomic analysis was performed using tandem-mass spectrometry. In vivo efficacy of WU-NK-101 ± Ctx was evaluated in NSG mice bearing LoVo xenograft CRC tumors. Cell trafficking/penetration to TME was measured by tracking labeled WU-NK-101 ± trastuzumab in NSG mice bearing subcutaneous SKOV-3 xenografts. Results: Compared to conventional NK cells (cNK), WU-NK-101 had a unique phenotype consistent with rapid activation and proliferation (higher expression of activating receptors, Ki67, and GZMB), and showed enhanced in vitro cytotoxicity. WU-NK-101 also exhibited potent cytotoxicity against LoVo CRC tumors in vivo, which was further enhanced in combination with Ctx. Antibody combination improved WU-NK-101 penetration, and persistence in TME. WU-NK-101’s metabolic profile was consistent with aerobic (Warburg) glycolysis, potentially facilitating effector functions in the TME. WU-NK-101 also showed enhanced metabolic fitness and flexibility, as proteins in several metabolic pathways were upregulated in TME vs N media. Consistent with this, WU-NK-101 had increased cell-surface expression of nutrient transporters. While cNK and T cells cytotoxicity was significantly suppressed in TME-aligned media, WU-NK-101’s function was not impacted. Conclusions: We show that WU-NK-101 exerted potent activity against CRC, and in combination with Ctx showed improved intra-tumor infiltration/persistence and anti-tumor activity. Also, WU-NK-101 cells had enhanced metabolic fitness/flexibility and decreased susceptibility to immunosuppression, overcoming limitations encountered by ACT for solid tumors. A Phase 1b clinical trial is in development, which may reshape ACT in CRC and other EGFR-expressing tumors. [Table: see text]

Children with acute myeloid leukemia (AML) have a poor prognosis despite the intensification of chemotherapy. Future efforts to improve outcomes should focus on more precise targeting of leukemia cells. CD123, or IL3RA, is expressed on the surface of nearly all pediatric AML samples and is a high-priority target for immunotherapy. The efficacy of an investigational dual-affinity retargeting antibody (DART) molecule (CD123 × CD3; MGD006 or flotetuzumab) was assessed in two distinct patient-derived xenograft (PDX) models of pediatric AML. MGD006 simultaneously binds to CD123 on target cells and CD3 on effector T cells, thereby activating T cells and redirecting them to induce cytotoxicity in target cells. The concurrent treatment of cytarabine and MGD006 was performed to determine the effect of cytarabine on T-cell counts and MGD006 activity. Treatment with MGD006 along with an allogeneic human T-cell infusion to act as effector cells induced durable responses in both PDX models, with CD123 positivity. This effect was sustained in mice treated with a combination of MGD006 and cytarabine in the presence of T cells. MGD006 enhanced T-cell proliferation and decreased the burden of AML blasts in the peripheral blood with or without cytarabine treatment. These data demonstrate the efficacy of MGD006 in prolonging survival in pediatric AML PDX models in the presence of effector T cells and show that the inclusion of cytarabine in the treatment regimen does not interfere with MGD006 activity.

Primary central nervous system lymphoma (PCNSL) is a rare extra-nodal B-cell non-Hodgkin lymphoma, which arises in the brain, spinal cord, meninges, or eyes. In individuals infected with HIV, PCNSL occurs with advanced immunosuppression and low CD4 T-cell count. It is considered an AIDS-defining malignancy. Unlike PCNSL in immune-competent hosts, AIDS-related PCNSL (AR-PCNSL) is almost exclusively caused by a cancer-causing herpesvirus, Epstein–Barr Virus (EBV, also known as human herpesvirus-4). While PCNSL in immune-competent patients and AR-PCNSL have pathologic and clinical overlap, AR-PCNSL is distinguished by its strong association with immunosuppression and viral etiology.