Single-Dose Anti-PD-L1/IL-15 Fusion Protein KD033 Generates Synergistic Antitumor Immunity with Robust Tumor-Immune Gene Signatures and Memory Responses

Translational PK/PD and the first-in-human dose selection of a PD1/IL15: an engineered recombinant targeted cytokine for cancer immunotherapy

Introduction

Interleukin 15 (IL-15) is a potential anticancer agent and numerous engineered IL-15 agonists are currently under clinical investigation. Selective targeting of IL-15 to specific lymphocytes may enhance therapeutic effects while helping to minimize toxicities.

Methods

We designed and built a heterodimeric targeted cytokine (TaCk) that consists of an anti-programmed cell death 1 receptor antibody (anti-PD-1) and an engineered IL-15. This "PD1/IL15" selectively delivers IL-15 signaling to lymphocytes expressing PD-1. We then investigated the pharmacokinetic (PK) and pharmacodynamic (PD) effects of PD1/IL15 TaCk on immune cell subsets in cynomolgus monkeys after single and repeat intravenous dose administrations. We used these results to determine the first-in-human (FIH) dose and dosing frequency for early clinical trials.

Results

The PD1/IL15 TaCk exhibited a nonlinear multiphasic PK profile, while the untargeted isotype control TaCk, containing an anti-respiratory syncytial virus antibody (RSV/IL15), showed linear and dose proportional PK. The PD1/IL15 TaCk also displayed a considerably prolonged PK (half-life range ∼1.0-4.1 days) compared to wild-type IL-15 (half-life ∼1.1 h), which led to an enhanced cell expansion PD response. The PD was dose-dependent, durable, and selective for PD-1+ lymphocytes. Notably, the dose- and time-dependent PK was attributed to dynamic TMDD resulting from test article-induced lymphocyte expansion upon repeat administration. The recommended first-in-human (FIH) dose of PD1/IL15 TaCk is 0.003 mg/kg, determined based on a minimum anticipated biological effect level (MABEL) approach utilizing a combination of in vitro and preclinical in vivo data.

Conclusion

This work provides insight into the complex PK/PD relationship of PD1/IL15 TaCk in monkeys and informs the recommended starting dose and dosing frequency selection to support clinical evaluation of this novel targeted cytokine.

Development of pharmacological immunoregulatory anti-cancer therapeutics: current mechanistic studies and clinical opportunities

Immunotherapy represented by anti-PD-(L)1 and anti-CTLA-4 inhibitors has revolutionized cancer treatment, but challenges related to resistance and toxicity still remain. Due to the advancement of immuno-oncology, an increasing number of novel immunoregulatory targets and mechanisms are being revealed, with relevant therapies promising to improve clinical immunotherapy in the foreseeable future. Therefore, comprehending the larger picture is important. In this review, we analyze and summarize the current landscape of preclinical and translational mechanistic research, drug development, and clinical trials that brought about next-generation pharmacological immunoregulatory anti-cancer agents and drug candidates beyond classical immune checkpoint inhibitors. Along with further clarification of cancer immunobiology and advances in antibody engineering, agents targeting additional inhibitory immune checkpoints, including LAG-3, TIM-3, TIGIT, CD47, and B7 family members are becoming an important part of cancer immunotherapy research and discovery, as are structurally and functionally optimized novel anti-PD-(L)1 and anti-CTLA-4 agents and agonists of co-stimulatory molecules of T cells. Exemplified by bispecific T cell engagers, newly emerging bi-specific and multi-specific antibodies targeting immunoregulatory molecules can provide considerable clinical benefits. Next-generation agents also include immune epigenetic drugs and cytokine-based therapeutics. Cell therapies, cancer vaccines, and oncolytic viruses are not covered in this review. This comprehensive review might aid in further development and the fastest possible clinical adoption of effective immuno-oncology modalities for the benefit of patients.

Next-generation anti-PD-L1/IL-15 immunocytokine elicits superior antitumor immunity in cold tumors with minimal toxicity

The clinical applications of immunocytokines are severely restricted by dose-limiting toxicities. To address this challenge, here we propose a next-generation immunocytokine concept involving the design of LH05, a tumor-conditional anti-PD-L1/interleukin-15 (IL-15) prodrug. LH05 innovatively masks IL-15 with steric hindrance, mitigating the "cytokine sink" effect of IL-15 and reducing systemic toxicities associated with wild-type anti-PD-L1/IL-15. Moreover, upon specific proteolytic cleavage within the tumor microenvironment, LH05 releases an active IL-15 superagonist, exerting potent antitumor effects. Mechanistically, the antitumor efficacy of LH05 depends on the increased infiltration of CD8+ T and natural killer cells by stimulating the chemokines CXCL9 and CXCL10, thereby converting cold tumors into hot tumors. Additionally, the tumor-conditional anti-PD-L1/IL-15 can synergize with an oncolytic virus or checkpoint blockade in advanced and metastatic tumor models. Our findings provide a compelling proof of concept for the development of next-generation immunocytokines, contributing significantly to current knowledge and strategies of immunotherapy.

Facts and Hopes on Chimeric Cytokine Agents for Cancer Immunotherapy

Cytokines are key mediators of immune responses that can modulate the antitumor activity of immune cells. Cytokines have been explored as a promising cancer immunotherapy. However, there are several challenges to cytokine therapy, especially a lack of tumor targeting, resulting in high toxicity and limited efficacy. To overcome these limitations, novel approaches have been developed to engineer cytokines with improved properties, such as chimeric cytokines. Chimeric cytokines are fusion proteins that combine different cytokine domains or link cytokines to antibodies (immunocytokines) or other molecules that can target specific receptors or cells. Chimeric cytokines can enhance the selectivity and stability of cytokines, leading to reduced toxicity and improved efficacy. In this review, we focus on two promising cytokines, IL2 and IL15, and summarize the current advances and challenges of chimeric cytokine design and application for cancer immunotherapy. Most of the current approaches focus on increasing the potency of cytokines, but another important goal is to reduce toxicity. Cytokine engineering is promising for cancer immunotherapy as it can enhance tumor targeting while minimizing adverse effects.

Cancer immunity by tissue-resident type 1 innate lymphoid cells and killer innate-like T cells

Cancer progression can be restrained by tumor-infiltrating lymphocytes in a process termed cancer immunosurveillance. Based on how lymphocytes are activated and recruited to the tumor tissue, cancer immunity is either pre-wired, in which innate lymphocytes and innate-like T cells are directly recruited to and activated in tumors following their differentiation in primary lymphoid organs; or priming-dependent, in which conventional adaptive T cells are first primed by cognate antigens in secondary lymphoid organs before homing to and reactivated in tumors. While priming-dependent cancer immunity has been a focus of cancer immunology research for decades, in part due to historical preconception of cancer theory and tumor model choice as well as clinical success of conventional adaptive T cell-directed therapeutic programs, recent studies have revealed that pre-wired cancer immunity mediated by tissue-resident type 1 innate lymphoid cells (ILC1s) and killer innate-like T cells (ILTCKs) is an integral component of the cancer immunosurveillance process. Herein we review the distinct ontogenies and cancer-sensing mechanisms of ILC1s and ILTCKs in murine genetic cancer models as well as the conspicuously conserved responses in human malignancies. How ILC1s and ILTCKs may be targeted to broaden the scope of cancer immunotherapy beyond conventional adaptive T cells is also discussed.

GT-00AxIL15, a Novel Tumor-Targeted IL-15-Based Immunocytokine for the Treatment of TA-MUC1-Positive Solid Tumors: Preclinical In Vitro and In Vivo Pharmacodynamics and Biodistribution Studies

GT-00AxIL15 is a novel interleukin-15-based immunocytokine targeting a tumor-specific, glycosylated epitope of MUC1 (TA-MUC1). We characterized mode of action, pharmacokinetic (PK) and pharmacodynamic (PD) properties and investigated the relevance of TA-MUC1 binding for the concept of delivering IL-15 to solid tumors. In vitro pharmacology was analyzed in binding and cell-based assays. The in vivo PK profile and IL-15-mediated PD effects of GT-00AxIL15 were investigated in tumor-free mice. Tumor accumulation, immune infiltration and anti-tumor activity were assessed in TA-MUC1+ syngeneic and xenogeneic murine tumor models. GT-00AxIL15 was shown to specifically bind TA-MUC1 on tumor cells via its mAb moiety, to IL-15 receptors on immune cells via its IL-15 fusion modules and to FcγRs via its functional Fc-part. In vitro, NK, NKT and CD8+ T cells were activated and proliferated, leading to anti-tumor cytotoxicity and synergism with antibody-dependent cellular cytotoxicity (ADCC)-mediating mAbs. In vivo, GT-00AxIL15 exhibited favorable PK characteristics with a serum half-life of 13 days and specifically accumulated in TA-MUC1+ tumors. In the tumor microenvironment, GT-00AxIL15 induced robust immune activation and expansion and mediated anti-metastatic and anti-tumor effects in syngeneic and xenograft tumor models. These results support the rationale to improve PK and anti-tumor efficacy of IL-15 by increasing local concentrations at the tumor site via conjugation to a TA-MUC1 binding mAb. The tumor-selective expression pattern of TA-MUC1, powerful immune activation and anti-tumor cytotoxicity, long serum half-life and tumor targeting properties, render GT-00AxIL15 a promising candidate for treatment of solid tumors with high medical need, e.g., ovarian, lung and breast cancer.

Therapeutic Fusion Proteins

Therapeutic fusion proteins are a class of hybrid constructs that combine distinct biomolecules into a single platform with the additive effects of the components. The ability to fuse two unrelated proteins provides a means to localize mechanisms to better treat a range of diseases. Fusion proteins can be designed to impart diverse functions, including increasing half-life, providing targeting, and enabling sustained signaling. Of these, half-life extenders, which are fused to a therapeutic protein to increase exposure, are the most established group of fusion proteins, with many clinical successes. Rapid advances in antibody and antibody-derivative technology have enabled the fusion of targeting domains with therapeutic proteins. An emerging group of therapeutic fusion proteins has two separate active functions. Although most research for therapeutic fusion proteins focuses on cancer, prior successes provide a foundation for studies into other diseases as well. The exponential emergence of biopharmaceuticals gives precedence for increased research into therapeutic fusion proteins for a multitude of diseases.

In vitro modelling of local gene therapy with IL-15/IL-15Rα and a PD-L1 antagonist in melanoma reveals an interplay between NK cells and CD4+ T cells

Blockade of the immune checkpoint axis consisting of programmed death-1 (PD-1) and its ligand PD-L1 alleviates the functional inhibition of tumor-infiltrating lymphoid cells yet weakly induces their expansion. Exogenous cytokines could further expand lymphoid cells and thus synergize with αPD-L1 therapy. However, systemic delivery of most cytokines causes severe toxicity due to unspecific expansion of immune cells in the periphery. Here, we modelled local delivery of cytokines and αPD-L1 therapeutics to immune cell-containing in vitro melanoma tumors. Three-dimensional tumor models consisting of 624-MEL cells were co-cultured with human peripheral blood lymphoid cells (PBLs) in presence of the cytokines IL-2, IL-7, IL-15, IL-21 and IFN-γ. To model local gene therapy, melanoma tumors were modified with lentiviral vectors encoding IL-15 fused to IL-15Rα (IL-15/IL-15Rα) and K2-Fc, a fusion of a human PD-L1 specific single domain antibody to immunoglobulin (Ig)G1 Fc. To evaluate the interplay between PBL fractions, NK cells, CD4+ T cells or CD8+ T cells were depleted. Tumor cell killing was followed up using real time imaging and immune cell expansion and activation was evaluated with flow cytometry. Among the tested cytokines, IL-15 was the most potent cytokine in stimulating tumor cell killing and expanding both natural killer (NK) cells and CD8+ T cells. Gene-based delivery of IL-15/IL-15Rα to tumor cells, shows expansion of NK cells, activation of NK cells, CD4+ and CD8+ T cells, and killing of tumor spheroids. Both NK cells and CD8+ T cells are necessary for tumor cell killing and CD4+ T-cell activation was reduced without NK cells. Co-delivery of K2-Fc improved tumor cell killing coinciding with increased activation of NK cells, which was independent of bystander T cells. CD4+ or CD8+ T cells were not affected by the co-delivery of K2-Fc even though NK-cell activation impacted CD4+ T-cell activation. This study demonstrates that gene-based delivery of IL-15/IL-15Rα to tumor cells effectively mediates anti-tumor activity and sensitizes the tumor microenvironment for therapy with αPD-L1 therapeutics mainly by impacting NK cells. These findings warrant further investigation of gene-based IL-15 and K2-Fc delivery in vivo.

Strategies to therapeutically modulate cytokine action

Cytokines are secreted or membrane-presented molecules that mediate broad cellular functions, including development, differentiation, growth and survival. Accordingly, the regulation of cytokine activity is extraordinarily important both physiologically and pathologically. Cytokine and/or cytokine receptor engineering is being widely investigated to safely and effectively modulate cytokine activity for therapeutic benefit. IL-2 in particular has been extensively engineered, to create IL-2 variants that differentially exhibit activities on regulatory T cells to potentially treat autoimmune disease versus effector T cells to augment antitumour effects. Additionally, engineering approaches are being applied to many other cytokines such as IL-10, interferons and IL-1 family cytokines, given their immunosuppressive and/or antiviral and anticancer effects. In modulating the actions of cytokines, the strategies used have been broad, including altering affinities of cytokines for their receptors, prolonging cytokine half-lives in vivo and fine-tuning cytokine actions. The field is rapidly expanding, with extensive efforts to create improved therapeutics for a range of diseases.

Evaluation of the clinical molecule anti-human-PD-L1/IL-15 KD033 in the human-PD-1/PD-L1-expressing murine model demonstrates PD-L1 targeting of IL-15 in vivo

KD033 is a clinical-stage immunocytokine composed of a high-affinity anti-human-PD-L1 antibody and the human IL-15/ IL-15 receptor sushi-domain complex. We have previously shown that KD033-surrogate, the anti-mouse-PD-L1/IL-15 immunocytokine, was efficacious in several syngeneic murine tumor models including those that were refractory to anti-PD-1/PD-L1 checkpoint blockers. KD033-surrogate showed better efficacy than the combination treatment of its component, anti-PD-L1 antibody with the non-targeting IL-15. KD033-surrogate was also efficacious in both low and high PD-L1-expressing tumors. In this study, we have utilized double knock-in mice expressing functional human PD-1/PD-L1 to show that the clinical molecule, KD033, reproduced the anti-tumor efficacy observed with KD033-surrogate in the syngeneic models. KD033 was equally efficacious in reducing the growth of human-PD-L1 positive (hPDL1+) and negative (hPDL1-) MC38 murine tumors. We observed similar peripheral pharmacodynamics changes in KD033-treated mice bearing either hPDL1+ or hPDL1- MC38 tumors. However, different transcriptomic profiles were observed between KD033-treated hPDL1+ and hPDL1- MC38 tumors with marked changes involving mostly downregulated genes in hPDL1- tumors in addition to the immune-related genes changes observed in both hPDL1+ and hPDL1- MC38 tumors. Cytotoxic and myeloid cell signatures were upregulated in both tumors with relatively greater increases observed in hPDL1- MC38 tumors. These effects of KD033 treatment in PD-L1 positive and negative tumors demonstrate the role of PD-L1 in targeting of IL-15 cytokine in vivo.

Targeted Cytokine Delivery for Cancer Treatment: Engineering and Biological Effects

Anti-tumor properties of several cytokines have already been investigated in multiple experiments and clinical trials. However, those studies evidenced substantial toxicities, even at low cytokine doses, and the lack of tumor specificity. These factors significantly limit clinical applications. Due to their high specificity and affinity, tumor-specific monoclonal antibodies or their antigen-binding fragments are capable of delivering fused cytokines to tumors and, therefore, of decreasing the number and severity of side effects, as well as of enhancing the therapeutic index. The present review surveys the actual antibody-cytokine fusion protein (immunocytokine) formats, their targets, mechanisms of action, and anti-tumor and other biological effects. Special attention is paid to the formats designed to prevent the off-target cytokine-receptor interactions, potentially inducing side effects. Here, we describe preclinical and clinical data and the efficacy of the antibody-mediated cytokine delivery approach, either as a single therapy or in combination with other agents.

A novel anti-PD-L1/IL-15 immunocytokine overcomes resistance to PD-L1 blockade and elicits potent antitumor immunity

Despite the demonstrated immense potential of immune checkpoint inhibitors in various types of cancers, only a minority of patients respond to these therapies. Immunocytokines designed to deliver an immune-activating cytokine directly to the immunosuppressive tumor microenvironment (TME) and block the immune checkpoint simultaneously may provide a strategic advantage over the combination of two single agents. To increase the response rate to checkpoint blockade, in this study, we developed a novel immunocytokine (LH01) composed of the antibody against programmed death-ligand 1 (PD-L1) fused to interleukin (IL)-15 receptor alpha-sushi domain/IL-15 complex. We demonstrate that LH01 efficiently binds mouse or human PD-L1 and maintains IL-15 stimulatory activity. In syngeneic mouse models, LH01 showed improved antitumor efficacy and safety versus anti-PD-L1 plus LH02 (Fc-sushi-IL15) combination and overcame resistance to anti-PD-L1 treatment. Mechanistically, the dual anti-immunosuppressive function of LH01 activated both the innate and adaptive immune responses and induced a favorable and immunostimulatory TME. Furthermore, combination therapy with LH01 and bevacizumab exerts synergistic antitumor effects in an HT29 colorectal xenograft model. Collectively, our results provide supporting evidence that fusion of anti-PD-L1 and IL-15 might be a potent strategy to treat patients with cold tumors or resistance to checkpoint blockade.

Contribution of natural killer cells in innate immunity against colorectal cancer

Natural killer cells are members of the innate immune system and promote cytotoxic activity against tumor or infected cells independently from MHC recognition. NK cells are modulated by the expression of activator/inhibitory receptors. The ratio of this activator/inhibitory receptors is responsible for the cytotoxic activity of NK cells toward the target cells. Owing to the potent anti-tumor properties of NK cells, they are considered as interesting approach in tumor treatment. Colorectal cancer (CRC) is the second most common cause of death in the world and the incidence is about 2 million new cases per year. Metastatic CRC is accompanied by a poor prognosis with less than three years of overall survival. Chemotherapy and surgery are the most adopted treatments. Besides, targeted therapy and immune checkpoint blockade are novel approach to CRC treatment. In these patients, circulating NK cells are a prognostic marker. The main target of CRC immune cell therapy is to improve the tumor cell's recognition and elimination by immune cells. Adaptive NK cell therapy is the milestone to achieve the purpose. Allogeneic NK cell therapy has been widely investigated within clinical trials. In this review, we focus on the NK related approaches including CAR NK cells, cell-based vaccines, monoclonal antibodies and immunomodulatory drugs against CRC tumoral cells.

The role of interleukin-15 in the development and treatment of hematological malignancies

Cytokines are a vital component of the immune system that controls the activation and growth of blood cells. However, chronic overexpression of cytokines can trigger cellular events leading to malignant transformation. The cytokine interleukin-15 (IL-15) is of particular interest, which has been shown to contribute to the development and progression of various hematological malignancies. This review will provide an overview of the impact of the immunopathogenic function of IL-15 by studying its role in cell survival, proliferation, inflammation, and treatment resistance. We will also review therapeutic approaches for inhibiting IL-15 in blood cancers.

An engineered concealed IL-15-R elicits tumor-specific CD8+T cell responses through PD-1-cis delivery

Checkpoint blockade immunotherapy releases the inhibition of tumor-infiltrating lymphocytes (TILs) but weakly induces TIL proliferation. Exogenous IL-15 could further expand TILs and thus synergize with αPD-L1 therapy. However, systemic delivery of IL-15 extensively expands peripheral NK cells, causing severe toxicity. To redirect IL-15 to intratumoral PD-1+CD8+T effector cells instead of NK cells for better tumor control and lower toxicity, we engineered an anti-PD-1 fusion with IL-15-IL-15Rα, whose activity was geographically concealed by immunoglobulin Fc region with an engineered linker (αPD-1-IL-15-R) to bypass systemic NK cells. Systematic administration of αPD-1-IL-15-R elicited extraordinary antitumor efficacy with undetectable toxicity. Mechanistically, cis-delivery of αPD-1-IL-15-R vastly expands tumor-specific CD8+T cells for tumor rejection. Additionally, αPD-1-IL-15-R upregulated PD-1 and IL-15Rβ on T cells to create a feedforward activation loop, thus rejuvenating TILs, not only resulting in tumor control in situ, but also suppressing tumor metastasis. Collectively, renavigating IL-15 to tumor-specific PD-1+CD8+T cells, αPD-1-IL-15-R elicits effective systemic antitumor immunity.

Preclinical evaluation of IAP0971, a novel immunocytokine that binds specifically to PD1 and fuses IL15/IL15R complex

Background

Currently, cytokine therapy for cancer has demonstrated efficacy in certain diseases but is generally accompanied by severe toxicity. The field of antibody-cytokine fusion proteins (immunocytokines) arose to target these effector molecules to the tumor microenvironment to expand the therapeutic window of cytokine therapy. Therefore, we have developed a novel immunocytokine that binds specifically to programmed death 1 (PD1) and fuses IL15/IL15Rα complex (referred to as IAP0971) for cancer immunotherapy.

Methods

We report here the making of IAP0971, a novel immunocytokine that binds specifically to PD1 and fuses IL15/IL15Rα complex, and preclinical characterization including pharmacology, pharmacodynamics, pharmacokinetics and toxicology, and discuss its potential as a novel agent for treating patients with advanced malignant tumors.

Results

IAP0971 bound to human IL2/15Rβ proteins specifically and blocked PD1/PDL1 signaling transduction pathway. IAP0971 promoted the proliferation of CD8 + T cells and natural killer T (NKT) cells, and further activated NK cells to kill tumor cells validated by in vitro assays. In an hPD1 knock-in mouse model, IAP0971 showed potent anti-tumor activity. Preclinical studies in non-human primates following single or repeated dosing of IAP0971 showed favorable pharmacokinetics and well-tolerated toxicology profile.

Conclusion

IAP0971 has demonstrated a favorable safety profile and potent anti-tumor activities in vivo. A Phase I/IIa clinical trial to evaluate the safety, tolerability and preliminary efficacy of IAP0971 in patients with advanced malignant tumors is on-going (NCT05396391).

Preclinical Evaluation of Recombinant Human IL15 Protein Fused with Albumin Binding Domain on Anti-PD-L1 Immunotherapy Efficiency and Anti-Tumor Immunity in Colon Cancer and Melanoma

Simple Summary

In this manuscript, we reported that a newly developed recombinant human IL15 fused with albumin binding domain (hIL15-ABD) showed superior biological half-life, pharmacokinetic and anti-tumor immunity than wild-type (WT) hIL15. Our hIL-15-ABD can effectively enhance anti-tumor efficacy of anti-PD-L1 on colon cancer and melanoma animal models. The anti-tumor potential of hIL-15-ABD was associated with tumor microenvironment (TME) regulation, including the activation of NK cells and CD8⁺ T cells, the reduction of immunosuppressive cells (MDSCs and Tregs) and the suppression of immunosuppressive factors (IDO, FOXP3 and VEGF). In conclusion, our new hIL15-ABD combined with anti-PD-L1 antibody increased the activity of anti-tumor effector cells involved in both innate and adaptive immunities, decreased the TME’s immunosuppressive cells, and showed greater anti-tumor effect than that of either monotherapy. We suggested hIL15-ABD as the potential complementary agent may effectively augment the therapeutic efficacy of anti-PD-L1 antibody in colon cancer and melanoma model.

Abstract

Anti-PD-L1 antibody monotherapy shows limited efficacy in a significant proportion of the patients. A common explanation for the inefficacy is a lack of anti-tumor effector cells in the tumor microenvironment (TME). Recombinant human interleukin-15 (hIL15), a potent immune stimulant, has been investigated in clinical trial with encouraging results. However, hIL15 is constrained by the short half-life of hIL15 and a relatively unfavorable pharmacokinetics profile. We developed a recombinant fusion IL15 protein composed of human IL15 (hIL15) and albumin binding domain (hIL15-ABD) and explored the therapeutic efficacy and immune regulation of hIL-15, hIL15-ABD and/or combination with anti-PD-L1 on CT26 murine colon cancer (CC) and B16-F10 murine melanoma models. We demonstrated that hIL15-ABD has significant inhibitory effect on the CT26 and B16-F10 tumor growths as compared to hIL-15. hIL-15-ABD not only showed superior half-life and pharmacokinetics data than hIL-15, but also enhance anti-tumor efficacy of antibody against PD-L1 via suppressive effect on accumulation of Tregs and MDSCs and activation of NK and CD8+T cells. Immune suppressive factors including VEGF and IDO were also decreased by combination treatment. hIL15-ABD combined with anti-PD-L1 antibody increased the activity of anti-tumor effector cells involved in both innate and adaptive immunities, decreased the TME’s immunosuppressive cells, and showed greater anti-tumor effect than that of either monotherapy.