Autologous Natural Killer Cells Research Articles

Syngeneic natural killer cell therapy activates dendritic and T cells in metastatic lungs and effectively treats low-burden metastases.

Natural killer (NK) cells can control metastasis through cytotoxicity and IFN-γ production independently of T cells in experimental metastasis mouse models. The inverse correlation between NK activity and metastasis incidence supports a critical role for NK cells in human metastatic surveillance. However, autologous NK cell therapy has shown limited benefit in treating patients with metastatic solid tumors. Using a spontaneous metastasis mouse model of MHC-I+ breast cancer, we found that transfer of IL-15/IL-12-conditioned syngeneic NK cells after primary tumor resection promoted long-term survival of mice with low metastatic burden and induced a tumor-specific protective T cell response that is essential for the therapeutic effect. Furthermore, NK cell transfer augments activation of conventional dendritic cells (cDCs), Foxp3-CD4+ T cells and stem cell-like CD8+ T cells in metastatic lungs, to which IFN-γ of the transferred NK cells contributes significantly. These results imply direct interactions between transferred NK cells and endogenous cDCs to enhance T cell activation. We conducted an investigator-initiated clinical trial of autologous NK cell therapy in six patients with advanced cancer and observed that the NK cell therapy was safe and showed signs of effectiveness. These findings indicate that autologous NK cell therapy is effective in treating established low burden metastases of MHC-I+ tumor cells by activating the cDC-T cell axis at metastatic sites.

Syngeneic natural killer cell therapy activates dendritic and T cells in metastatic lungs and effectively treats low-burden metastases

Natural killer (NK) cells can control metastasis through cytotoxicity and IFN-γ production independently of T cells in experimental metastasis mouse models. The inverse correlation between NK activity and metastasis incidence supports a critical role for NK cells in human metastatic surveillance. However, autologous NK cell therapy has shown limited benefit in treating patients with metastatic solid tumors. Using a spontaneous metastasis mouse model of MHC-I+ breast cancer, we found that transfer of IL-15/IL-12-conditioned syngeneic NK cells after primary tumor resection promoted long-term survival of mice with low metastatic burden and induced a tumor-specific protective T cell response that is essential for the therapeutic effect. Furthermore, NK cell transfer augments activation of conventional dendritic cells (cDCs), Foxp3-CD4+ T cells and stem cell-like CD8+ T cells in metastatic lungs, to which IFN-γ of the transferred NK cells contributes significantly. These results imply direct interactions between transferred NK cells and endogenous cDCs to enhance T cell activation. We conducted an investigator-initiated clinical trial of autologous NK cell therapy in six patients with advanced cancer and observed that the NK cell therapy was safe and showed signs of effectiveness. These findings indicate that autologous NK cell therapy is effective in treating established low burden metastases of MHC-I+ tumor cells by activating the cDC-T cell axis at metastatic sites.

Subjects treated with expanded non‐genetically modified autologous Natural Killer cells (SNK01) show improved changes in CSF α‐synuclein and in cognitive function

Subjects treated with expanded non‐genetically modified autologous Natural Killer cells (SNK01) show improved changes in CSF α‐synuclein and in cognitive function

IMMU-69. THERAPEUTIC WINDOW ENABLING ERADICATION OF RESIDUAL GLIOMA STEM CELLS BY INTRACRANIAL NK CELL THERAPY FOLLOWING TEMOZOLOMIDE-INDUCED TUMOUR DEPOPULATION – A POSSIBLE ROLE OF CYTOTOXIC EXTRACELLULAR VESICLES

Abstract Glioblastoma (GBM) is an incurable brain cancer, where dismal outcomes result from disease recurrence driven by tumour-initiating glioma stem cells (GSCs). GSCs survive and expand in the brain after surgery, radiation and temozolomide (TMZ) amidst weak immune and natural killer (NK) cell surveillance. Efficient NK cell-mediated killing of GBM cells occurs at high effector to target ratios precluding effective eradication of large tumour remnants, as enforced by clinical trials with autologous NK cells in an adjuvant setting. Here we explore in a human GSC xenograft model whether tumor depopulation using high dose Temozolomide (TMZ) could create a window of curative opportunity for endogenous or exogenous NK cells. We observed that while subcutaneous (sc) xenografts of patient derived GSCs are infiltrated by endogenous functional (NCR1+) NK cells in SCID mice, the corresponding intracranial (ic) tumours remained NK cell depleted. Notably, while TMZ caused near complete regression of intracranial GSC xenografts this was followed by inevitable recurrence of drug-resistant lesions. To explore whether direct delivery of NK cells into depopulated intracranial tumours would change the lethal course of the disease, mice were injected with GSCs intracranially, and upon tumour formation were treated with a sequence of TMZ (systemically), at 2, 7, 14, and 21 days later with irradiated NK92MI cells. Remarkably, this combined therapy completely obliterated recurrent disease at 2 and 7 days but not beyond 14 days. To assess whether NK92MI cells could be replaced by their derived extracellular vesicles (NK-EVs), the latter were injected i.c. post TMZ in GSC xenograft bearing mice. A single injection of NK-EVs resulted in tumour eradication in some but not all mice. Thus, chemotherapy-dependent tumour depopulation may create a unique window of opportunity for curative NK-mediated immunotherapy in GBM.

NK Cell-Based Cancer Immunotherapies: Current Progress, Challenges and Emerging Opportunities.

Natural killer (NK) cells are vital innate immune cells that play a crucial role in cancer therapy. They are targeted by therapies designed to modulate, retain, and enhance their antitumor function in vivo. In addition to whole-cell therapy, NK cell-derived exosomes (NDEs) offer high immune safety and are easily subject to chemical, biological, and immunological modifications. This makes them suitable for use in combination with various current cancer therapies to enhance efficacy, treatment outcomes, and reduce side effects in vivo. This review aims to outline summarizes the antitumor potential of NK cells, as well as the current challenges and opportunities in NK cell-based immunotherapies such as allogeneic and autologous NK cell transplantation, CAR NK cell therapy, and the use of cytokines and monoclonal antibodies. The review also explores the dual regulatory effects of tumor exosomes on NK cells, and highlights the potential of NDEs, either alone or in combination with other antitumor therapies, to reprogram the immunosuppressive tumor microenvironment and expedite the therapeutic effects of cancer immunotherapy in future clinical research.

Harnessing the Power of NK Cell Receptor Engineering as a New Prospect in Cancer Immunotherapy.

Natural killer (NK) cells have recently gained popularity as an alternative for cancer immunotherapy. Adoptive cell transfer employing NK cells offers a safer therapeutic option compared to T-cell-based therapies, due to their significantly lower toxicity and the availability of diverse autologous and allogeneic NK cell sources. However, several challenges are associated with NK cell therapies, including limited in vivo persistence, the immunosuppressive and hostile tumor microenvironment (TME), and the lack of effective treatments for solid tumors. To address these limitations, the modification of NK cells to stably produce cytokines has been proposed as a strategy to enhance their persistence and proliferation. Additionally, the overexpression of activating receptors and the blockade of inhibitory receptors can restore the NK cell functions hindered by the TME. To further improve tumor infiltration and the elimination of solid tumors, innovative approaches focusing on the enhancement of NK cell chemotaxis through the overexpression of chemotactic receptors have been introduced. This review highlights the latest advancements in preclinical and clinical studies investigating the engineering of activating, inhibitory, and chemotactic NK cell receptors; discusses recent progress in cytokine manipulation; and explores the potential of combining the chimeric antigen receptor (CAR) technology with NK cell receptors engineering.

Impact of monocytes on the proliferation of highly activated NK-like cells (GAIA-102)

Abstract [Background] There has been a growing clinical application of therapies using autologous and allogeneic natural killer (NK) cells. Researchers across the field have been developing various methods to amplify NK cells, highlighting the increasing importance of NK cell amplification techniques. We have already developed a technique to amplify highly active NK-like cells (GAIA-102) from allogeneic peripheral blood mononuclear cells (PBMCs) with several cytokines, and currently conducting three clinical trials utilizing this technology. However, it remains unclear which components of PBMCs contribute to the proliferation of NK cells, a question that is central to further advancing this field.[Method] We utilized magnetic beads to deplete various blood cell components from PBMCs to investigate the effects of the presence or absence of each component on the cultivation of GAIA-102. We then evaluated the dynamics of cell proliferation and surface marker expression changes.[Results] The removal of specific components did not impact the cytotoxicity or the surface marker profile (ITGA1+/CXCR3+/CCR5+/CCR6+) of the original GAIA-102. Interestingly, eliminating monocytes from the culture markedly decreased GAIA-102 cell proliferation, a more substantial effect than when B cells were removed.[Conclusions] Our study suggests that monocytes may play a crucial role of GAIA-102 proliferation. Unraveling the impact of monocytes on this process will be a vital direction for future research.

Phase 1 study combining elotuzumab with autologous stem cell transplant and lenalidomide for multiple myeloma

BackgroundAutologous stem cell transplantation (ASCT) after induction therapy improves disease-free survival for patients with multiple myeloma (MM). While the goal of ASCT is to render a minimal disease state, it...

Safety and efficacy of SNK01 (autologous natural killer cells) in combination with cytotoxic chemotherapy and/or cetuximab after failure of prior tyrosine kinase inhibitor in non-small cell lung cancer: non-clinical mouse model and phase I/IIa clinical study

BackgroundChoosing treatments for epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC) patients with osimertinib resistance is challenging. We evaluated the safety and efficacy of SNK01 (autologous natural killer...

Bispecific antibodies promote natural killer cell-mediated elimination of HIV-1 reservoir cells

The persistence of CD4+ T cells carrying latent human immunodeficiency virus-1 (HIV-1) proviruses is the main barrier to a cure. New therapeutics to enhance HIV-1-specific immune responses and clear infected cells will probably be necessary to achieve reduction of the latent reservoir. In the present study, we report two single-chain diabodies (scDbs) that target the HIV-1 envelope protein (Env) and the human type III Fcγ receptor (CD16). We show that the scDbs promoted robust and HIV-1-specific natural killer (NK) cell activation and NK cell-mediated lysis of infected cells. Cocultures of CD4+ T cells from people with HIV-1 on antiretroviral therapy (ART) with autologous NK cells and the scDbs resulted in marked elimination of reservoir cells that was dependent on latency reversal. Treatment of human interleukin-15 transgenic NSG mice with one of the scDbs after ART initiation enhanced NK cell activity and reduced reservoir size. Thus, HIV-1-specific scDbs merit further evaluation as potential therapeutics for clearance of the latent reservoir.

Epigenetic Scarring Leads to Irreversible NK Cell Dysfunction in Myeloid Malignancies

Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) belong to the same spectrum of myeloid malignancies and have extremely poor outcomes in the relapsed/refractory setting. Despite advances in the understanding of the pathogenesis and molecular mechanisms of these disorders, and incremental improvements in treatment regimens, patients with MDS and AML often relapse and fail to achieve cure. These and other factors underscore the urgent need for new therapeutic alternatives that will improve the clinical outcomes of these patients. Immunotherapy using checkpoint molecule inhibitors and adoptive cell therapy using autologous immune effector cells have been mostly unsuccessful in patients with MDS and AML. This could be due to the immunosuppressive tumor microenvironment in the bone marrow niche or to intrinsic dysfunction in the immune effector cells of these patients. Natural killer (NK) cells are innate lymphocytes that play an important role in cancer immune surveillance and have distinct advantages over T cells as candidates for immunotherapy. Myeloid blasts are inherently susceptible to NK cell-mediated killing as they express many of the ligands recognized by NK cell activating receptors. However, malignant myeloid blasts are capable of adapting and developing defense mechanisms that allow them to evade NK cell-mediated cytotoxicity. Little is known about the mechanisms of NK cell immune evasion developed by myeloid blasts. Here, we show that NK cells from patients with myeloid malignancies display a global dysfunction with severely impaired secretory function and killing capacity. Single cell RNAseq and mass cytometry experiments revealed that these NK cells from MDS and AML patients display an exhausted phenotype at the transcriptomic and proteomic levels. We also show that these NK cells have an altered metabolism compared with age matched healthy control NK cells. We show that this dysfunction is mediated by a crosstalk between myeloid blasts and NK cells and cell-cell contact dependent release of transforming growth factor beta (TGF-β). This crosstalk leads to a profound epigenetic reprogramming of NK cells driven by transcription factors known to mediate exhaustion and immune suppression. Myeloid blast-induced NK dysfunction and epigenetic state of exhaustion can be prevented by pharmacologically inhibiting the TGF-β pathway or knockout of TGFBR2 in NK cells. However, our data reveal that once this dysfunction occurs it is irreversible owing to epigenetic scarring driven by the transcription factor BATF. In fact, we show that TGF-β induces the expression of BATF in NK cells, which in turn mediates a gene regulatory program leading to NK cell dysfunction by driving the expression of exhaustion and inhibitory genes (e.g. HAVCR2, ENTPD1, CTLA4, TGFBR2). Collectively, our findings reveal a novel mechanism of NK cell immune evasion manifested by stable epigenetic rewiring and inactivation of NK cells by myeloid blasts. Our data support the use of allogeneic sources for adoptive NK cell therapy in combination with strategies aiming at preventing immune suppression to treat myeloid malignancies rather than therapies aiming at reversing or rescuing the function of autologous NK cells.

IMMU-55. THERAPEUTIC WINDOW ENABLING ERADICATION OF RESIDUAL GLIOMA STEM CELLS BY INTRACRANIAL NK CELL AND EXTRACELLULAR VESICLE-MEDIATED THERAPY FOLLOWING TEMOZOLOMIDE-INDUCED TUMOUR DEPOPULATION

Abstract Glioblastoma (GBM) is an incurable brain cancer, where dismal outcomes result from disease recurrence driven by tumour-initiating glioma stem cells (GSCs). GSCs survive and expand in the brain after surgery, radiation and temozolomide (TMZ) amidst weak immune and natural killer (NK) cell surveillance. NK cell-mediated killing of GBM cells occurs at effector to target rations precluding effective eradication as enforced by clinical trials with autologous NK cells in an adjuvant setting. Here we explore in a human GSC xenograft model whether tumor depopulation using high dose Temozolomide (TMZ) could create a window of curative opportunity for endogenous or exogenous NK cells. We observed that while subcutaneous (sc) xenografts of patient derived GSCs are infiltrated by endogenous functional (NCR1+) NK cells in SCID mice, the corresponding intracranial (ic) tumours remained NK cell depleted. In NK-deficient NSG mice, neither site contained functional NK cells. Notably, while TMZ caused near complete regression of GSC xenografts in both strains of mice and both locations (sc and ic), this was followed by recurrence of drug resistant lesions in all cases except NK-infiltrated sc SCID xenografts. This effect was obliterated by anti-sialo GM1 treatment. To explore whether direct delivery of NK cells into depopulated intracranial tumours would change the lethal course of the disease, mice were injected with GSCs ic, and upon tumour formation were treated with a sequence of TMZ (systemically), and two days later with irradiated NK92MI. Remarkably, this combined therapy completely obliterated recurrent disease. To assess whether NK92MI cells could be replaced by their derived extracellular vesicles (NK-EVs), the latter were injected i.c. post TMZ in GSC xenograft bearing mice. A single injection of NK-EVs resulted in tumour eradication in some but not all mice. Thus, chemotherapy-dependent tumour depopulation may create a unique window of opportunity for curative NK-mediated immunotherapy in GBM.

Innate Cell Engager (ICE®) AFM13 Combined with Preactivated and Expanded (P+E) Cord Blood (CB)-Derived Natural Killer (NK) Cells for Patients with Refractory CD30-Positive Lymphomas: Final Results

CONCLUSIONS Pts with refractory Hodgkin (HL) and other CD30+ lymphomas have few effective therapies available and targeted NK cell immunotherapy is an active area of research. Transfer of non-targeted NK cells has shown limited clinical benefit as target recognition of cancer cells by NK cells constitutes a barrier. The innate cell engager AFM13 is a first-in-class CD30/CD16A bispecific antibody construct that induces selective killing of CD30+ tumor cells by engaging and activating NK cells. As a single agent, AFM13 has limited clinical activity against HL, likely due to the reduced effector function of autologous NK cells in these pts, which provides the rationale for combining AFM13 with allogeneic NK cells. Our prior preclinical work identified a promising combination of CB-derived NK cells that were first IL-12/IL-15/IL-18-preactivated followed by ex vivo expansion (P+E) with engineered K562 feeder cells expressing membrane-bound IL-21, 4-1BBL and CD48 and exogenous IL-2, and subsequently complexed with AFM13 just before infusion; these cytokine-induced memory-like NK cells presented chimeric antigen receptor (CAR)-NK-like features and increased in vitro and in vivo antitumor activity compared to either non-AFM13-precomplexed P+E NK cells or to AFM13 alone (Kerbauy et al, Clin Cancer Res 2021). Building on this work we wished to study this CB NK-cell therapy in pts with refractory CD30+ lymphomas. This investigator-initiated single-center phase I-II trial (NCT04074746) evaluated the safety and activity of P+E AFM13-precomplexed CB NK cells followed by systemic AFM13. Pts ages 15-75 with CD30+ lymphomas refractory to brentuximab vedotin were enrolled. The goals were to identify the recommended phase 2 dose (RP2D) of NK cells, estimate the overall (ORR) and complete response (CR), event-free (EFS) and overall survival (OS) rates, and study NK cell activation and persistence. Each treatment cycle consisted of fludarabine/cyclophosphamide (days −5 to −3) followed by infusion (day 0) of the AFM13-precomplexed CB NK cells, cultured for 14 days as described above, and three weekly IV infusions of AFM13 (200 mg, days 7, 14 and 21). Two cycles were planned for pts 1-19 and up to 4 cycles from patient 20 on. Response was evaluated on day 28 of each cycle. Enrollment proceeded at 3 dose levels (DL) of 10 6, 10 7 and 10 8 NK/Kg, respectively. Each patient received the same NK dose in all cycles. Between 09/20-12/22 we enrolled 42 pts (37 HL, 5 NHL), pretreated with a median 7 lines, at DL1 (N=3), DL2 (N=3) and DL3 (N=36), with 1 (N=2), 2 (N=21), 3 (N=3) or 4 cycles (N=16). All had active progressive disease at enrollment and no bridging therapy was given. The cords used for each of the 117 cycles were selected without consideration for HLA match, which was 0/6 (N=53), 1/6 (N=46), 2/6 (N=14), 3/6 (N=3) and 4/6 (N=1). The product infused consisted of >94% NK cells (expanded >2,700 fold), with only 0.02% T cells. The NK cells were 96% viable, 91% bound to AFM13, and 97.6% CD16+. The products were infused fresh. There was 1 grade 2 infusion-related reaction (IRR) in 115 infusions of AFM13-NK (0.8%) and 27 IRR infusion related reactions in 350 infusions of AFM13 (7.7%) (1 G3, 26 G2). We saw no cases of CRS, ICANS or GVHD of any grade. DL3 (10 8 NK/Kg) was established as the RP2D. The ORR and CR were 92.8% and 66.7%, respectively (94.4% and 72.2%, respectively, in 36 pts treated at the RP2D). Nine pts had a response consolidated with SCT (5 allo, 4 auto). At median follow-up of 14 (6-34) months, the EFS/OS rates are 31%/76%; median EFS/OS are 8 months/not reached. No relapses were associated with antigen loss. In the subset of pts planned for 4 cycles at RP2D, 15 of 23 pts remained event free at 6 mo (4 pts with and 11 without SCT consolidation), for 6-month EFS/OS rates of 65%/83%. Overall, 8 of the 9 pts (89%) receiving a consolidation SCT are event free at 10 to 34 months. AFM-bound CB NK cells were detected in blood from day 1 post infusion for up to 3 weeks. Donor NK levels followed similar patterns after each cycle, which argues against a sensitization after the first NK infusion. CyTOF studies showed increased expression of AFM13 and activation markers in donor NK cells. We confirmed trafficking of AFM13-bound donor NK cells to tumor sites shortly after infusion. CB-derived cytokine-induced memory-like NK cells precomplexed with AFM13 have excellent tolerability and activity for pts with heavily pretreated and refractory CD30+ lymphoma.

Investigating the novel CD16A and epidermal growth factor receptor (EGFR) bispecific innate cell engager, AFM24, to leverage the innate immune system: Interim results from the colorectal cancer (CRC) cohort.

e14508 Background: AFM24 is a tetravalent, bispecific innate cell engager that binds EGFR on solid tumors and CD16A on natural killer (NK) cells. AFM24 redirects NK cells to EGFR-expressing (EGFR+) solid tumors, enhancing antibody-dependent cellular cytotoxicity. AFM24 induced lysis of EGFR+ tumor cell lines in vitro independent of EGFR expression level and mutation status. The dose escalation phase (Phase 1) of the presented study (NCT04259450) previously established the recommended Phase 2 dose at 480 mg based on tolerability, receptor occupancy, and pharmacokinetics. Correlative science data revealed an activation and enrichment of immune cells in the tumor microenvironment. Here we present preliminary data from the Phase 2a CRC expansion cohort. Methods: The Phase 2a expansion phase is evaluating 480 mg AFM24 in patients with histologically or cytologically confirmed microsatellite stable, RAS wild type EGFR+ CRC. Patients have relapsed or refractory disease to ≥2 prior lines of therapy including an EGFR targeted therapy. EGFR+ is defined as positive staining for EGFR in ≥1% of tumor cells per local immunohistochemistry assay. The study follows Simon’s two-stage design. The primary endpoint is the overall response rate per RECIST v1.1 by investigator assessment; secondary endpoints include safety and tolerability; efficacy per iRECIST is exploratory. AFM24 is administered intravenously once weekly in a 28-day cycle. Tumor assessments are performed at screening, cycles 2, 4, 6, 8, and every 3 cycles thereafter. Results: As of December 2022, 16 patients with Stage 4 CRC were enrolled and treated with 480 mg AFM24 in the study. The median (range) age was 66 years (51–77); 11 males and 5 females; 9 Asian, 7 White). The median number of prior therapies was 4 (2–7) and the median treatment duration was 5.1 weeks (1.0–22.0). Treatment-related adverse events (TRAEs) were reported in 14/16 patients; infusion-related reactions (IRRs, 12), pruritus (3), lymphopenia (3), and anemia (2) were the most common. AFM24 TRAEs of Grade ≥3 occurred in 6 patients and included lymphopenia (3), decreased neutrophil count (1), increased blood bilirubin (1) and IRRs (1). To date, no objective responses were observed. Seven patients remain on treatment including 1 patient with confirmed stable disease ongoing for 5 months exhibiting a tumor reduction of –17%. Final interim results will be presented. Conclusions: The novel mechanism of action of AFM24 may provide an alternative treatment approach for patients with EGFR+ solid tumors. In this study, AFM24 monotherapy was adequately tolerated in a heavily pretreated population of patients with EGFR+ CRC. AFM24 is also being investigated in combination with atezolizumab and autologous NK cells in various EGFR+ solid tumors. Clinical trial information: NCT04259450 .

The safety and efficacy of SNK01 (autologous natural killer cells) in combination with cytotoxic chemotherapy after failure of prior tyrosine kinase inhibitor in non-small cell lung cancer: Preclinical mouse model and phase I/IIa clinical study.

9057 Background: It is challenging to choose subsequent treatment option in patients with Osimertinib resistance in epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC). Meanwhile, antitumor effect of the antibody-dependent cellular cytotoxicity of natural killer (NK) cells mediated by cetuximab –anti-EGFR monoclonal antibody– has been reported. Therefore, we aimed to evaluate the safety and efficacy of SNK01 (non-genetically modified autologous NK cell) in combination with cytotoxic chemotherapy including cetuximab in NSCLC after failure to prior tyrosine kinase inhibitor (TKI) in a preclinical humanized cell line-derived xenograft (CDX) mouse model and phase I/IIa clinical study. Methods: We established a humanized CDX mouse model using Osimertinib-resistant lung cancer cell line. Reconstruction of the humanized mouse, CDX-related skills, and analytic data were made according to C&SR Inc. manufacturing technique & SOP protocol. The mice were divided into 4 groups based on treatment (no treatment [n = 2]; Cetuximab only [n = 3]; SNK01 only [n = 4]; SNK01 plus Cetuximab [n = 4]) and treated weekly for 5 weeks (SNK01, 1x107 cells/dose; Cetuximab, 20 ug/dose). In the clinical study, 12 patients with EGFR-mutated NSCLC who failed prior TKI treatment were finally enrolled. They received weekly SNK01 in combination with Gemcitabine/Carboplatin (n = 6) or Gemcitabine/Carboplatin/Cetuximab (n = 6), and dose escalation of SNK01 following “3+3” design (4×109 cells/dose or 6×109 cells/dose). The primary endpoint was safety, and secondary endpoint was efficacy. Results: In the preclinical study, flow cytometry analysis showed that NK cells (CD45+/CD56+/CD3-) were significantly increased in the groups administrated SNK01. The volume of tumor extracted after completion of treatment was the smallest in SNK01 plus cetuximab group. In the clinical study, the median age of patients was 61 years, 33.3% were male, and all patients had adenocarcinoma. The enrolled patients received weekly infusions of SNK01 for 7 to 8 weeks (4×109 cells/dose [n = 6]; 6×109 cells/dose [n = 6]). Since dose limiting toxicity was not observed, maximum tolerated dose of SNK01 was determined to be 6×109 cells/dose. SNK01-related adverse event ≥grade 3 was also not observed. In the efficacy analysis, objective response rate was 25%, disease control rate was 100% (partial response, n = 3/12; stable disease, n = 9/12), and median progression free survival (PFS) was 143 days. PFS will be updated as some patients are still being followed. Conclusions: SNK01 in combination with cytotoxic chemotherapy, including cetuximab in EGFR-mutated NSCLC with resistance to TKI was safe and showed a potential antitumor effect in this preclinical study and early phase I/IIa clinical trial. Clinical trial information: NCT04872634 .

Signatures of HIV-infected CD4 +T cell resistance to NK cell-mediated killing

Abstract BACKGROUND: In vitroexperiments in which HIV-infected CD4 +T cells are co-cultured with natural killer (NK) cells yield incomplete elimination of the infected cells. We therefore hypothesize that cell-intrinsic pathways in CD4 +T cells are differentially regulated in HIV-infected cells to mediate resistance to NK cell-mediated killing. METHODS: Mock-infected and HIV-89.6-infected CD4 +T cells from 6 HIV −donors were co-cultured overnight +/− autologous NK cells. Following co-culture, cells were stained for the surface exposed HIV envelope protein using fluorescently conjugated HIV antibodies. Fluorescence activated cell sorting was then used to isolate infected and uninfected cells, followed by bulk RNA-sequencing. Transcripts from infected and uninfected cells co-cultured overnight with versus without NK cells were compared. RESULTS: RNA-seq analysis of CD4 +T cells that survived co-culture with NK cells revealed dozens of differentially expressed genes in infected, but not uninfected cells. This included upregulation of interferon-stimulated genes, including PD-L1 (p adj=3×10 −6), and NF-kB-related genes. Additional upregulated genes in the surviving infected cells included c-Fos (p adj=1.9×10 −5), c-Jun (p adj=4.9×10 −8), and cathepsin L (p adj=5×10 −3). CONCLUSIONS: NF-kB genes that are downregulated in infected cells, potentially through Vpu activity, are normalized in surviving infected cells. This may be due to NK cell targeting of Vpu-mediated HLA-C downregulation. Deconvolution of the relative contributions of specific genes/proteins to target cell resistance will reveal novel targets for the development of therapeutics to eliminate the HIV reservoir.

Mycobacterium abscessus resists the innate cellular response by surviving cell lysis of infected phagocytes.

Mycobacterium abscessus is the most pathogenic species among the predominantly saprophytic fast-growing mycobacteria. This opportunistic human pathogen causes severe infections that are difficult to eradicate. Its ability to survive within the host was described mainly with the rough (R) form of M. abscessus, which is lethal in several animal models. This R form is not present at the very beginning of the disease but appears during the progression and the exacerbation of the mycobacterial infection, by transition from a smooth (S) form. However, we do not know how the S form of M. abscessus colonizes and infects the host to then multiply and cause the disease. In this work, we were able to show the hypersensitivity of fruit flies, Drosophila melanogaster, to intrathoracic infections by the S and R forms of M. abscessus. This allowed us to unravel how the S form resists the innate immune response developed by the fly, both the antimicrobial peptides- and cellular-dependent immune responses. We demonstrate that intracellular M. abscessus was not killed within the infected phagocytic cells, by resisting lysis and caspase-dependent apoptotic cell death of Drosophila infected phagocytes. In mice, in a similar manner, intra-macrophage M. abscessus was not killed when M. abscessus-infected macrophages were lysed by autologous natural killer cells. These results demonstrate the propensity of the S form of M. abscessus to resist the host's innate responses to colonize and multiply within the host.

The Correlation between Peripheral Blood Index and Immune Cell Expansion in Vietnamese Elderly Lung Cancer Patients.

(1) Background: The dysfunction and reduced proliferation of peripheral CD8+ T cells and natural killer (NK) cells have been observed in both aging and cancer patients, thereby challenging the adoption of immune cell therapy in these subjects. In this study, we evaluated the growth of these lymphocytes in elderly cancer patients and the correlation of peripheral blood (PB) indices to their expansion. (2) Method: This retrospective study included 15 lung cancer patients who underwent autologous NK cell and CD8+ T cell therapy between January 2016 and December 2019 and 10 healthy individuals. (3) Results: On average, CD8+ T lymphocytes and NK cells were able to be expanded about 500 times from the PB of elderly lung cancer subjects. Particularly, 95% of the expanded NK cells highly expressed the CD56 marker. The expansion of CD8+ T cells was inversely associated with the CD4+:CD8+ ratio and the frequency of PB-CD4+ T cells in PB. Likewise, the expansion of NK cells was inversely correlated with the frequency of PB-lymphocytes and the number of PB-CD8+ T cells. The growth of CD8+ T cells and NK cells was also inversely correlated with the percentage and number of PB-NK cells. (4) Conclusion: PB indices are intrinsically tied to immune cell health and could be leveraged to determine CD8 T and NK cell proliferation capacity for immune therapies in lung cancer patients.

Predictive biomarkers for the responsiveness of recurrent glioblastomas to activated killer cell immunotherapy

BackgroundRecurrent glioblastoma multiforme (GBM) is a highly aggressive primary malignant brain tumor that is resistant to existing treatments. Recently, we reported that activated autologous natural killer (NK) cell therapeutics induced a marked increase in survival of some patients with recurrent GBM.MethodsTo identify biomarkers that predict responsiveness to NK cell therapeutics, we examined immune profiles in tumor tissues using NanoString nCounter analysis and compared the profiles between 5 responders and 7 non-responders. Through a three-step data analysis, we identified three candidate biomarkers (TNFRSF18, TNFSF4, and IL12RB2) and performed validation with qRT-PCR. We also performed immunohistochemistry and a NK cell migration assay to assess the function of these genes.ResultsResponders had higher expression of many immune-signaling genes compared with non-responders, which suggests an immune-active tumor microenvironment in responders. The random forest model that identified TNFRSF18, TNFSF4, and IL12RB2 showed a 100% accuracy (95% CI 73.5–100%) for predicting the response to NK cell therapeutics. The expression levels of these three genes by qRT-PCR were highly correlated with the NanoString levels, with high Pearson’s correlation coefficients (0.419 (TNFRSF18), 0.700 (TNFSF4), and 0.502 (IL12RB2)); their prediction performance also showed 100% accuracy (95% CI 73.54–100%) by logistic regression modeling. We also demonstrated that these genes were related to cytotoxic T cell infiltration and NK cell migration in the tumor microenvironment.ConclusionWe identified TNFRSF18, TNFSF4, and IL12RB2 as biomarkers that predict response to NK cell therapeutics in recurrent GBM, which might provide a new treatment strategy for this highly aggressive tumor.

Innate Cell Engager AFM13 Combined with Preactivated and Expanded Cord Blood-Derived NK Cells for Patients with Double Refractory CD30+ Lymphoma

Patients with multiple relapsed or refractory (R/R) Hodgkin lymphoma (HL) and other CD30+ lymphoma have few effective therapies available and targeted adoptive natural killer (NK) cell immunotherapy is an active area of investigation. Transfer of non-targeted NK cells has shown limited clinical benefit as target recognition of cancers by NK cells remains a substantial barrier. The innate cell engager (ICE®) construct, AFM13, is a first-in-class CD30/CD16A bispecific antibody construct that induces specific and selective killing of CD30+ tumor cells by engaging and activating NK cells. As a single agent, AFM13 has limited clinical activity against HL, likely due to the reduced effector function of autologous NK cells in these patients, which provides the rationale for the combination of AFM13 with allogeneic NK cells. Our prior preclinical work identified a promising combination of cord blood (CB)-derived NK cells that were first IL-12/IL-15/IL-18-preactivated followed by expansion (P+E) with engineered K562 feeder cells expressing membrane-bound IL-21, 4-1BB ligand and CD48 ex vivo, and subsequently complexed with AFM13 just prior to infusion (Kerbauy et al, Clin Cancer Res 2021; 27:3744-56). These cytokine-induced memory-like CB-derived NK cells precomplexed with AFM13 (AFM13-NK) presented chimeric antigen receptor (CAR)-NK cell-like features and showed an increased in vitro and in vivo antitumor activity compared to either P+E NK or AFM13 alone. Building on this work we wished to clinically study adoptive AFM13-NK cell therapy in pts with R/R CD30+ lymphomas. METHODS: This single-center phase I-II trial (NCT04074746) evaluates the safety and activity of AFM13-NK, followed by AFM13 monotherapy. Patients aged 15-75 years with R/R CD30+ lymphomas refractory to brentuximab vedotin are enrolled. The trial goals are to identify the recommended phase 2 dose (RP2D) of AFM13-NK cells, estimate the overall (ORR) and complete response (CR) rates, event-free (EFS) and overall survival (OS) rates, and studies of NK cell activation and persistence. Each treatment cycle consisted of fludarabine/cyclophosphamide (days −5 to −3), followed by infusion of the AFM13-NK cells, cultured for 14 days as described above (day 0), and three weekly IV infusions of AFM13 (200 mg, days 7, 14 and 21). Two cycles were administered to patients 1-19 and 4 cycles were given starting with patient 20. Response was evaluated on day 28 of each cycle. Patients were enrolled at 3 dose levels: DL1 (106 NK/Kg), DL2 (107NK/Kg) and DL3 (108 NK/Kg). Each patient received the same NK dose in all cycles. RESULTS: As of 7/31/22, 30 pts have been enrolled and treated (Table) at DL1 (N=3), DL2 (N=3) and DL3 (N=24), with 1 (N=1), 2 (N=24), 3 (N=3) or 4 cycles (N=3). All patients had active progressive disease at enrollment and no bridging therapy was given. The cords used for each of the 69 cycles were selected with no consideration for HLA match, which was 0/6 (N=31), 1/6 (N=31), 2/6 (N=5), 3/6 (N=1) and 4/6 (N=1). The product infused consisted of >99% NK cells (expanded >2,700 fold), with only 0.02% T cells. The NK cells were >98% viable and 92% of them were bound to AFM13. The products were infused fresh. There were no infusion-related reactions (IRR) after infusing AFM13-NK and 11 IRR in 182 infusions of AFM13 alone (6%) (1 grade 3, 10 grade 2). We saw no cases of CRS, ICANS or GVHD of any grade. DL3 (108 NK/Kg) was established as the RP2D. The ORR in the entire study is 97% with 63% CRs. All 24 patients treated at the RP2D responded (100% ORR) with 70.8% (17/24) CRs. Five patients had a response consolidated with a SCT. At median follow-up of 8 (range 1-23) months, the EFS and OS rates of all 30 patients are 57% and 83%, respectively. AFM-NK cells were detected in serum from day 1 post infusion and persisted for 3-4 weeks. Donor NK levels followed similar patterns after each cycle, which argues against a sensitization effect in the patient after the first NK infusion. Donor NK cells showed by CyTOF increased binding to AFM13 and expression of activation markers. CONCLUSIONS: This is the first clinical trial to date using an ICE® construct precomplexed with cytokine-induced memory-like CB-NK cells to treat patients with CD30+ R/R HL and NHL. Our preliminary results indicate that this ICE® precomplexed CB-NK cell therapy has an excellent tolerability profile and is highly active in patients with heavily pretreated R/R CD30+ lymphomas and warrants further investigation. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal