Heterodimeric IL-15 in Cancer Immunotherapy

Emerging role of PES1 in disease: A promising therapeutic target?

Pescadillo ribosomal biogenesis factor 1 (PES1), a nucleolar protein initially identified in zebrafish, plays an important role in embryonic development and ribosomal biogenesis. Notably, PES1 has been found to be overexpressed in a number of cancer types, where it contributes to tumorigenesis and cancer progression by promoting cell proliferation, suppressing cellular senescence, modulating the tumor microenvironment (TME) and promoting drug resistance in cancer cells. Moreover, recent emerging evidence suggests that PES1 expression is significantly elevated in the livers of Type 2 diabetes mellitus (T2DM) and obese patients, indicating its involvement in the pathogenesis of metabolic diseases through lipid metabolism regulation. In this review, we present the structural characteristics and biological functions of PES1, as well as complexes in which PES1 participates. Furthermore, we comprehensively summarize the multifaceted role of PES1 in various diseases and the latest insights into its underlying molecular mechanisms. Finally, we discuss the potential clinical translational perspectives of targeting PES1, highlighting its promising as a therapeutic intervention and treatment target.

Nanoenabled IL-15 Superagonist via Conditionally Stabilized Protein-Protein Interactions Eradicates Solid Tumors by Precise Immunomodulation

Protein complexes are crucial structures that control many biological processes. Harnessing these structures could be valuable for therapeutic therapy. However, their instability and short lifespans need to be addressed for effective use. Here, we propose an innovative approach based on a functional polymeric cloak that coordinately anchors different domains of protein complexes and assembles them into a stabilized nanoformulation. As the polymer-protein association in the cloak is pH sensitive, the nanoformulation also allows targeting the release of the protein complexes to the acidic microenvironment of tumors for aiding their therapeutic performance. Building on this strategy, we developed an IL-15 nanosuperagonist (Nano-SA) by encapsulating the interleukin-15 (IL-15)/IL-15 Receptor α (IL-15Rα) complex (IL-15cx) for fostering synergistic transpresentation in tumors. Upon intravenous administration, Nano-SA stably circulated in the bloodstream, safeguarding the integrity of IL-15cx until reaching the tumor site, where it selectively released the active complex. Thus, Nano-SA significantly amplified the antitumor immune signals while diminishing systemic off-target effects. In murine colon cancer models, Nano-SA achieved potent immunotherapeutic effects, eradicating tumors without adverse side effects. These findings highlight the transformative potential of nanotechnology for advancing protein complex-based therapies.

Neoprzewaquinone A alters the migration, phagocytosis and energy metabolism of IL-15-induced HMC3 cells

Microglia play a major role in the immune defense system of the central nervous system and are activated in many neurological diseases. The immunomodulatory cytokine interleukin (IL)-15 is known to be involved in microglia response and inflammatory factors release. Neoprzewaquinone A (NEO) is an active compound isolated from Salvia miltiorrhiza Bunge. Our previous study has shown that NEO significantly inhibit the proliferation of IL-15-treated Mo7e cells. However, the role of NEO in the structure and function of IL-15-treated human microglial cells (HMC3) remains unclear. Thus, our study aimed to quantitatively analyze the beneficial effects of NEO on HMC3 cells following IL-15 treatment. The cell viability, phagocytosis, migration and energy metabolism were evaluated by Cell Counting Kit-8 (CCK8), scratch assay, pHrodo™ Red Zymosan BioParticles™ Conjugate, and Agilent Seahorse XF Cell Mito Test. Cephalothin (CEP) was selected as a positive drug because it has obvious inhibitory effect on IL-15 and IL-15Rɑ. Our results showed that IL-15 stimulated the proliferation, migration and phagocytosis of HMC3 cells in a time-dependent manner. Interestingly, NEO exhibited significant suppressive effects on these IL-15-induced changes, which were even superior to those observed with the CEP. Moreover, IL-15 treatment did not significantly alter energy metabolism, including glycolysis and mitochondrial respiration. NEO and CEP alone effectively reduced glycolysis, non-mitochondrial respiration, basal respiration, ATP turnover, respiration capacity, and H+ leak in HMC3 cells. Furthermore, NEO displayed a partial regulatory effect on mitochondrial function in IL-15-treated HMC3 cells. Our study confirms the effectively inhibition of NEO on IL-15-induced microglial activation and provides valuable insights into the therapeutic prospects of NEO in neuropsychiatric disorders associated with IL-15 and microglia.

The JAK-STAT pathway: from structural biology to cytokine engineering

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway serves as a paradigm for signal transduction from the extracellular environment to the nucleus. It plays a pivotal role in physiological functions, such as hematopoiesis, immune balance, tissue homeostasis, and surveillance against tumors. Dysregulation of this pathway may lead to various disease conditions such as immune deficiencies, autoimmune diseases, hematologic disorders, and cancer. Due to its critical role in maintaining human health and involvement in disease, extensive studies have been conducted on this pathway, ranging from basic research to medical applications. Advances in the structural biology of this pathway have enabled us to gain insights into how the signaling cascade operates at the molecular level, laying the groundwork for therapeutic development targeting this pathway. Various strategies have been developed to restore its normal function, with promising therapeutic potential. Enhanced comprehension of these molecular mechanisms, combined with advances in protein engineering methodologies, has allowed us to engineer cytokines with tailored properties for targeted therapeutic applications, thereby enhancing their efficiency and safety. In this review, we outline the structural basis that governs key nodes in this pathway, offering a comprehensive overview of the signal transduction process. Furthermore, we explore recent advances in cytokine engineering for therapeutic development in this pathway.

Rapid transient and longer-lasting innate cytokine changes associated with adaptive immunity after repeated SARS-CoV-2 BNT162b2 mRNA vaccinations

Introduction

Cytokines and chemokines play an important role in shaping innate and adaptive immunity in response to infection and vaccination. Systems serology identified immunological parameters predictive of beneficial response to the BNT162b2 mRNA vaccine in COVID-19 infection-naïve volunteers, COVID-19 convalescent patients and transplant patients with hematological malignancies. Here, we examined the dynamics of the serum cytokine/chemokine responses after the 3rd BNT162b2 mRNA vaccination in a cohort of COVID-19 infection-naïve volunteers.

Methods

We measured serum cytokine and chemokine responses after the 3rd dose of the BNT162b2 mRNA (Pfizer/BioNtech) vaccine in COVID-19 infection-naïve individuals by a chemiluminescent assay and ELISA. Anti-Spike binding antibodies were measured by ELISA. Anti-Spike neutralizing antibodies were measured by a pseudotype assay.

Results

Comparison to responses found after the 1st and 2nd vaccinations showed persistence of the coordinated responses of several cytokine/chemokines including the previously identified rapid and transient IL-15, IFN-γ, CXCL10/IP-10, TNF-α, IL-6 signature. In contrast to the transient (24hrs) effect of the IL-15 signature, an inflammatory/anti-inflammatory cytokine signature (CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β, CXCL8/IL-8, IL-1Ra) remained at higher levels up to one month after the 2nd and 3rd booster vaccinations, indicative of a state of longer-lasting innate immune change. We also identified a systemic transient increase of CXCL13 only after the 3rd vaccination, supporting stronger germinal center activity and the higher anti-Spike antibody responses. Changes of the IL-15 signature, and the inflammatory/anti-inflammatory cytokine profile correlated with neutralizing antibody levels also after the 3rd vaccination supporting their role as immune biomarkers for effective development of vaccine-induced humoral responses.

Conclusion

These data revealed that repeated SARS-Cov-2 BNT162b2 mRNA vaccination induces both rapid transient as well as longer-lasting systemic serum cytokine changes associated with innate and adaptive immune responses.

Clinical trial registration

Clinicaltrials.gov, identifier NCT04743388.

First-in-human phase I/Ib study of NIZ985, a recombinant heterodimer of IL-15 and IL-15Rα, as a single agent and in combination with spartalizumab in patients with advanced and metastatic solid tumors

BACKGROUND

Preclinically, interleukin-15 (IL-15) monotherapy promotes antitumor immune responses, which are enhanced when IL-15 is used in combination with immune checkpoint inhibitors (ICIs). This first-in-human study investigated NIZ985, a recombinant heterodimer comprising physiologically active IL-15 and IL-15 receptor α, as monotherapy and in combination with spartalizumab, an anti-programmed cell death protein-1 (anti-PD-1) monoclonal antibody, in patients with advanced solid tumors.

METHODS

This phase I/Ib study had two dose-escalation arms: single-agent NIZ985 administered subcutaneously thrice weekly (TIW, 2 weeks on/2 weeks off) or once weekly (QW, 3 weeks on/1 week off), and NIZ985 TIW or QW administered subcutaneously plus spartalizumab (400 mg intravenously every 4 weeks (Q4W)). The dose-expansion phase investigated NIZ985 1 µg/kg TIW/spartalizumab 400 mg Q4W in patients with anti-PD-1-sensitive or anti-PD-1-resistant tumor types stratified according to approved indications. The primary objectives were the safety, tolerability, and the maximum tolerated doses (MTDs) and/or recommended dose for expansion (RDE) of NIZ985 for the dose-expansion phase.

RESULTS

As of February 17, 2020, 83 patients (median age: 63 years; range: 28-85) were treated in dose escalation (N=47; single-agent NIZ985: n=27; NIZ985/spartalizumab n=20) and dose expansion (N=36). No dose-limiting toxicities occurred nor was the MTD identified. The most common treatment-related adverse event (TRAE) was injection site reaction (primarily grades 1-2; single-agent NIZ985: 85% (23/27)); NIZ985/spartalizumab: 89% [50/56]). The most common grade 3-4 TRAE was decreased lymphocyte count (single-agent NIZ985: 7% [2/27]; NIZ985/spartalizumab: 5% [3/56]). The best overall response was stable disease in the single-agent arm (30% (8/27)) and partial response in the NIZ985/spartalizumab arm (5% [3/56]; melanoma, pancreatic cancer, gastric cancer). In dose expansion, the disease control rate was 45% (5/11) in the anti-PD-1-sensitive and 20% (5/25) in the anti-PD-1-resistant tumor type cohorts. Pharmacokinetic parameters were similar across arms. The transient increase in CD8+ T cell and natural killer cell proliferation and induction of several cytokines occurred in response to the single-agent and combination treatments.

CONCLUSIONS

NIZ985 was well tolerated in the single-agent and NIZ985/spartalizumab regimens. The RDE was established at 1 µg/kg TIW. Antitumor activity of the combination was observed against tumor types known to have a poor response to ICIs.

TRIAL REGISTRATION NUMBER

NCT02452268.

Cancer immunotherapy focusing on the role of interleukins: A comprehensive and updated study

Cytokines bind to specific receptors on target cells to activate intracellular signaling pathways that control diverse cellular functions, such as proliferation, differentiation, migration, and death. They are essential for the growth, activation, and operation of immune cells and the control of immunological reactions to pathogens, cancer cells, and other dangers. Based on their structural and functional properties, cytokines can be roughly categorized into different families, such as the tumor necrosis factor (TNF) family, interleukins, interferons, and chemokines. Leukocytes produce interleukins, a class of cytokines that have essential functions in coordinating and communicating with immune cells. Cancer, inflammation, and autoimmunity are immune-related disorders brought on by dysregulation of cytokine production or signaling. Understanding cytokines' biology to create novel diagnostic, prognostic, and therapeutic methods for various immune-related illnesses is crucial. Different immune cells, including T cells, B cells, macrophages, and dendritic cells, and other cells in the body, including epithelial cells and fibroblasts, generate and secrete interleukins. The present study's main aim is to fully understand interleukins' roles in cancer development and identify new therapeutic targets and strategies for cancer treatment.

IL-15 synergizes with CD40 agonist antibodies to induce durable immunity against bladder cancer

CD40 is a central costimulatory receptor implicated in productive antitumor immune responses across multiple cancers, including bladder cancer. Despite strong preclinical rationale, systemic administration of therapeutic agonistic antibodies targeting the CD40 pathway has demonstrated dose-limiting toxicities with minimal clinical activity, emphasizing an important need for optimized CD40-targeted approaches, including rational combination therapy strategies. Here, we describe a role for the endogenous IL-15 pathway in contributing to the therapeutic activity of CD40 agonism in orthotopic bladder tumors, with upregulation of transpresented IL-15/IL-15Rα surface complexes, particularly by cross-presenting conventional type 1 DCs (Dendritic Cells), and associated enrichment of activated CD8 T cells. In bladder cancer patient samples, we identify DCs as the primary source of IL-15, although they lack high levels of IL-15Rα at baseline. Using humanized immunocompetent orthotopic bladder tumor models, we demonstrate the ability to therapeutically augment this interaction through combined treatment with anti-CD40 agonist antibodies and exogenous IL-15, including the fully-human Fc-optimized antibody 2141-V11 currently in clinical development for the treatment of bladder cancer. Collectively, these data reveal an important role for IL-15 in mediating antitumor CD40 agonist responses in bladder cancer and provide key proof-of-concept for combined use of Fc-optimized anti-CD40 agonist antibodies and agents targeting the IL-15 pathway. These data support expansion of ongoing clinical studies evaluating anti-CD40 agonist antibodies and IL-15-based approaches to develop combinations of these promising therapeutics for the treatment of patients with bladder cancer.

MDM2 Inhibition Enhances Immune Checkpoint Inhibitor Efficacy by Increasing IL15 and MHC Class II Production

The treatment of patients with metastatic melanoma with immune checkpoint inhibitors (ICI) leads to impressive response rates but primary and secondary resistance to ICI reduces progression-free survival. Novel strategies that interfere with resistance mechanisms are key to further improve patient outcome during ICI therapy. P53 is often inactivated by mouse-double-minute-2 (MDM2), which may decrease immunogenicity of melanoma cells. We analyzed primary patient-derived melanoma cell lines, performed bulk sequencing analysis of patient-derived melanoma samples, and used melanoma mouse models to investigate the role of MDM2-inhibition for enhanced ICI therapy. We found increased expression of IL15 and MHC-II in murine melanoma cells upon p53 induction by MDM2-inhibition. MDM2-inhibitor induced MHC-II and IL15-production, which was p53 dependent as Tp53 knockdown blocked the effect. Lack of IL15-receptor in hematopoietic cells or IL15 neutralization reduced the MDM2-inhibition/p53-induction-mediated antitumor immunity. P53 induction by MDM2-inhibition caused anti-melanoma immune memory as T cells isolated from MDM2-inhibitor-treated melanoma-bearing mice exhibited anti-melanoma activity in secondary melanoma-bearing mice. In patient-derived melanoma cells p53 induction by MDM2-inhibition increased IL15 and MHC-II. IL15 and CIITA expressions were associated with a more favorable prognosis in patients bearing WT but not TP53-mutated melanoma.

IMPLICATIONS

MDM2-inhibition represents a novel strategy to enhance IL15 and MHC-II-production, which disrupts the immunosuppressive tumor microenvironment. On the basis of our findings, a clinical trial combining MDM2-inhibition with anti-PD-1 immunotherapy for metastatic melanoma is planned.

Exploiting an Interleukin-15 Heterodimeric Agonist (N803) for Effective Immunotherapy of Solid Malignancies

Identifying effective immunotherapies for solid tumors remains challenging despite the significant clinical responses observed in subsets of patients treated with immune checkpoint inhibitors. Interleukin-15 (IL-15) is a promising cytokine for the treatment of cancer as it stimulates NK and CD8⁺ lymphocytes. However, unfavorable pharmacokinetics and safety concerns render recombinant IL-15 (rIL-15) a less attractive modality. These shortcomings were addressed by the clinical development of heterodimeric IL-15 agonists, including N803. In preclinical tumor models, N803 elicited significant Th1 immune activation and tumor suppressive effects, primarily mediated by NK and CD8⁺ T lymphocytes. In addition, multiple clinical studies have demonstrated N803 to be safe for the treatment of cancer patients. The combination of N803 with the immune checkpoint inhibitor nivolumab demonstrated encouraging clinical responses in nivolumab-naïve and nivolumab-refractory patients with non-small cell lung cancer. In a recent Phase II/III clinical study, most Bacillus Calmette-Guerin (BCG)-refractory bladder cancer patients treated with N803 plus BCG experienced durable complete responses. Currently, N803 is being evaluated preclinically and clinically in combination with various agents, including chemotherapeutics, immune checkpoint inhibitors, vaccines, and other immuno-oncology agents. This report will review the mechanism(s) of action of N803 and how it relates to the preclinical and clinical studies of N803.

Tumor eradication by hetIL-15 locoregional therapy correlates with an induced intratumoral CD103intCD11b+ dendritic cell population

Locoregional monotherapy with heterodimeric interleukin (IL)-15 (hetIL-15) in a triple-negative breast cancer (TNBC) orthotopic mouse model resulted in tumor eradication in 40% of treated mice, reduction of metastasis, and induction of immunological memory against breast cancer cells. hetIL-15 re-shaped the tumor microenvironment by promoting the intratumoral accumulation of cytotoxic lymphocytes, conventional type 1 dendritic cells (cDC1s), and a dendritic cell (DC) population expressing both CD103 and CD11b markers. These CD103intCD11b+DCs share phenotypic and gene expression characteristics with both cDC1s and cDC2s, have transcriptomic profiles more similar to monocyte-derived DCs (moDCs), and correlate with tumor regression. Therefore, hetIL-15, a cytokine directly affecting lymphocytes and inducing cytotoxic cells, also has an indirect rapid and significant effect on the recruitment of myeloid cells, initiating a cascade for tumor elimination through innate and adoptive immune mechanisms. The intratumoral CD103intCD11b+DC population induced by hetIL-15 may be targeted for the development of additional cancer immunotherapy approaches.

Research progress of interleukin-15 in cancer immunotherapy

Interleukin-15 (IL-15) is a cytokine that belongs to the interleukin-2 (IL-2) family and is essential for the development, proliferation, and activation of immune cells, including natural killer (NK) cells, T cells and B cells. Recent studies have revealed that interleukin-15 also plays a critical role in cancer immunotherapy. Interleukin-15 agonist molecules have shown that interleukin-15 agonists are effective in inhibiting tumor growth and preventing metastasis, and some are undergoing clinical trials. In this review, we will summarize the recent progress in interleukin-15 research over the past 5 years, highlighting its potential applications in cancer immunotherapy and the progress of interleukin-15 agonist development.

PES1 reduces CD8+ T cell infiltration and immunotherapy sensitivity via interrupting ILF3-IL15 complex in esophageal squamous cell carcinoma

BACKGROUND

Although immune checkpoint blockade (ICB) therapy has brought survival benefits to patients with specific cancer types, most of cancer patients remain refractory to the ICB therapy, which is largely attributed to the immunosuppressive tumor microenvironment. Thereby, it is urgent to profile key molecules and signal pathways responsible for modification of tumor microenvironment.

METHODS

Multiple databases of esophageal squamous cell carcinoma (ESCC) were integratively analyzed to screen candidate genes responsible for infiltration of CD8⁺ T cells. Expression of pescadillo ribosomal biogenesis factor 1 (PES1) in clinical ESCC samples was examined by qRT-PCR, western blotting, and immunohistochemistry. The mechanisms of PES1 were investigated via RNA sequencing and mass spectrometry followed by immunoprecipitation and proximity ligation assay. The clinical and therapeutic significance of PES1 in ESCC was comprehensively investigated using ESCC cells and mouse model.

RESULTS

PES1 was significantly upregulated and correlated with poor prognosis in ESCC patients. PES1 knockdown decreased ESCC cell growth in vitro and in vivo and enhanced the efficacy of ICB therapy in mouse model, which was established through subcutaneous inoculation with ESCC cells. Analyses on RNA sequencing and mass spectrometry suggested that PES1 expression was negatively correlated with IL15 and ILF3 was one of the PES1-associated proteins. It has been known that ILF3 interacts with and stabilizes IL15 mRNA to increase IL15 protein level. Our data further indicated that PES1 interfered with the interaction between ILF3 and IL15 mRNA and impaired ILF3-mediated stabilization of IL15 mRNA, which eventually reduced the protein level of IL15. Interestingly, the inhibitory effect of ICB therapy boosted by PES1 knockdown dramatically antagonized by knockdown of IL15, which suppressed the tumor-infiltrated CD8⁺ T cells in ESCC. Finally, we confirmed the relationships among PES1, IL15, and CD8⁺ T cell infiltration in 10 locally advanced ESCC patients receiving ICB neoadjuvant therapy and demonstrated that ICB therapy would be more effective in those with low expression of PES1.

CONCLUSIONS

Altogether, our findings herein provided novel insights on biological function and clinical significance of PES1 and suggested that high expression of PES1 could suppress ILF3-IL15 axis-mediated immunosurveillance and promote resistance to ICB through restraining tumor-infiltrated CD8⁺ T cells.

IL-15 synergizes with CD40 agonist antibodies to induce durable immunity against bladder cancer

CD40 is a central co-stimulatory receptor implicated in the development of productive anti-tumor immune responses across multiple cancers, including bladder cancer. Despite strong preclinical rationale, systemic administration of therapeutic agonistic antibodies targeting the CD40 pathway have demonstrated dose limiting toxicities with minimal clinical activity to date, emphasizing an important need for optimized CD40-targeted approaches, including rational combination therapy strategies. Here, we describe an important role for the endogenous IL-15 pathway in contributing to the therapeutic activity of CD40 agonism in orthotopic bladder tumors, with upregulation of trans-presented IL-15/IL-15Rα surface complexes, particularly by cross-presenting cDC1s, and associated enrichment of activated CD8 T cells within the bladder tumor microenvironment. In bladder cancer patient samples, we identify DCs as the primary source of IL-15, however, they lack high levels of IL-15Rα at baseline. Using humanized immunocompetent orthotopic bladder tumor models, we demonstrate the ability to therapeutically augment this interaction through combined treatment with anti-CD40 agonist antibodies and exogenous IL-15, including the fully-human Fc-optimized antibody 2141-V11 currently in clinical development for the treatment of bladder cancer. Combination therapy enhances the crosstalk between Batf3-dependent cDC1s and CD8 T cells, driving robust primary anti-tumor activity and further stimulating long-term systemic anti-tumor memory responses associated with circulating memory-phenotype T and NK cell populations. Collectively, these data reveal an important role for IL-15 in mediating anti-tumor CD40 agonist responses in bladder cancer and provide key proof-of-concept for combined use of Fc-optimized anti-CD40 agonist antibodies and agents targeting the IL-15 pathway. These data support expansion of ongoing clinical studies evaluating anti-CD40 agonist antibodies and IL-15-based approaches to evaluate combinations of these promising therapeutics for the treatment of patients with bladder cancer.

Macrophage and monocyte subsets as new therapeutic targets in cancer immunotherapy

The introduction of immune checkpoint inhibitors (ICIs) for the treatment of solid cancers dramatically turned the tables in clinical routine. However, therapy success is still limited with up to 70% of non-responders in patients with ICI treatment. Traditionally, most immunotherapy approaches aim at directly stimulating anti-tumor T cell responses. More recently, tumor-associated macrophages have come into focus due to their predominance in solid tumors. Intensive cross-talk with tumor cells and immune as well as stromal cells within the tumor microenvironment can drive either pro- or anti-tumorigenic macrophage phenotypes. In turn, tumor-associated macrophages strongly shape cytokine and metabolite levels in the tumor microenvironment and thus are central players in anti-tumor immunity. Thus, ambivalent macrophage populations exist which raises therapeutic possibilities to either enhance or diminish their functionality. However, molecular signals controlling tumor-associated macrophage polarization are incompletely understood. Gaining in-depth understanding of monocyte/macrophage properties both in circulation and within distinct tumor microenvironments would (i) allow the development of new therapeutic approaches, and (ii) could additionally aid our understanding of underlying mechanisms limiting current therapy with the option of combinatorial therapies to increase efficacy. In this review, we summarize recent data addressing heterogeneity of tumor-associated macrophage populations and we discuss strategies to target macrophages using known molecular pathways with the potential for straight-forward clinical application.

INBRX-120, a CD8α-targeted detuned IL-2 that selectively expands and activates tumoricidal effector cells for safe and durable in vivo responses

BACKGROUND

As a major driver of lymphocyte proliferation and activation interleukin 2 (IL-2) is a crucial mediator for antitumor responses. Despite promising activity in a subset of patients, wider therapeutic utility of IL-2 (aldesleukin) has been hampered by severe dose-limiting toxicities, the expansion of immunosuppressive regulatory T cells and a poor pharmacokinetic (PK) profile. Recent engineering efforts, including non-α IL-2 variants, have lowered the toxicity profile, but have yet to induce meaningful antitumor activity in a wider patient population.

METHODS

We engineered INBRX-120, a CD8α-targeted Cisleukin™ molecule consisting of an affinity tuned IL-2 (IL2-x) connected to two high affinity CD8α-specific single domain antibodies via an effector-silenced Fc domain. To show that this large affinity differential enables directed IL-2 cis-signaling exclusively on CD8α-expressing tumoricidal effector cell populations, INBRX-120 effects on target cell expansion, activation and antitumor activity were tested in vitro. In vivo antitumor efficacy was evaluated in syngeneic mouse models alone or in combination with programmed cell death protein-1 (PD-1) blockade. Preclinical safety, as well as pharmacodynamic (PD) and PK profiling was carried out in non-human primates.

RESULTS

INBRX-120 effectively expanded and enhanced the cytotoxic capacity of CD8 T cells and natural killer cells towards tumor cells without affecting regulatory T cells in vitro and in vivo. In syngeneic mouse models, INBRX-120 surrogate showed safe, potent, and durable antitumor efficacy alone and in combination with PD-1 blockade. In non-human primates, INBRX-120 expanded and activated CD8α-expressing effector cells, showed a favorable PK profile, and was well tolerated up to a dose of 1 mg/kg.

CONCLUSIONS

Through its unique cis-signaling activity on CD8α-expressing effector cells, INBRX-120 overcomes the major limitations of IL-2-based therapy and effectively harnesses IL-2's potent intrinsic antitumor activity. This novel therapeutic strategy promises safer clinical activity that could induce meaningful antitumor efficacy in a wider set of patients with various cancer indications.

Heterodimeric IL-15 (hetIL-15) reduces circulating tumor cells and metastasis formation improving chemotherapy and surgery in 4T1 mouse model of TNBC

Immunotherapy has emerged as a viable approach in cancer therapy, with cytokines being of great interest. Interleukin IL-15 (IL-15), a cytokine that supports cytotoxic immune cells, has been successfully tested as an anti-cancer and anti-metastatic agent, but combinations with conventional chemotherapy and surgery protocols have not been extensively studied. We have produced heterodimeric IL-15 (hetIL-15), which has shown anti-tumor efficacy in several murine cancer models and is being evaluated in clinical trials for metastatic cancers. In this study, we examined the therapeutic effects of hetIL-15 in combination with chemotherapy and surgery in the 4T1 mouse model of metastatic triple negative breast cancer (TNBC). hetIL-15 monotherapy exhibited potent anti-metastatic effects by diminishing the number of circulating tumor cells (CTCs) and by controlling tumor cells colonization of the lungs. hetIL-15 treatment in combination with doxorubicin resulted in enhanced anti-metastatic activity and extended animal survival. Systemic immune phenotype analysis showed that the chemoimmunotherapeutic regimen shifted the tumor-induced imbalance of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) in favor of cytotoxic effector cells, by simultaneously decreasing PMN-MDSCs and increasing the frequency and activation of effector (CD8⁺T and NK) cells. Tumor resection supported by neoadjuvant and adjuvant administration of hetIL-15, either alone or in combination with doxorubicin, resulted in the cure of approximately half of the treated animals and the development of anti-4T1 tumor immunity. Our findings demonstrate a significant anti-metastatic potential of hetIL-15 in combination with chemotherapy and surgery and suggest exploring the use of this regimen for the treatment of TNBC.

The application of Interleukin-2 family cytokines in tumor immunotherapy research

The Interleukin-2 Family contains six kinds of cytokines, namely IL-2, IL-15, IL-4, IL-7, IL-9, and IL-21, all of which share a common γ chain. Many cytokines of the IL-2 family have been reported to be a driving force in immune cells activation. Therefore, researchers have tried various methods to study the anti-tumor effect of cytokines for a long time. However, due to the short half-life, poor stability, easy to lead to inflammatory storms and narrow safety treatment window of cytokines, this field has been tepid. In recent years, with the rapid development of protein engineering technology, some engineered cytokines have a significant effect in tumor immunotherapy, showing an irresistible trend of development. In this review, we will discuss the current researches of the IL-2 family and mainly focus on the application and achievements of engineered cytokines in tumor immunotherapy.

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).

Exponential Slope from Absolute Lymphocyte Counts during Radio-Chemotherapy Can Predict an Aggressive Course of Cervical Cancer

This study aimed to investigate whether the exponential slope α from absolute lymphocyte counts during concurrent radio−chemotherapy (CRT) is associated with aggressive and non-aggressive courses of cervical cancer. We analyzed 362 patients with stage IB−IVB cervical cancer treated with CRT in two groups: 323 patients without mRNA data (cohort 1) and 39 with mRNA data (cohort 2) from plasma exosomes. We calculated the α of each patient; 69 patients who died of cancer in cohort 1 were divided into 44 who died within 30 months (aggressive group), and 25 who died after more than 30 months (non-aggressive group). The median follow-up periods of cohorts 1 and 2 were 63 and 28 months, respectively. The log2 fold change (log2FC) between read counts of mRNAs before treatment and after the second week of CRT was calculated. Multivariate analyses from cohort 1 showed that neutrophil-to-lymphocyte ratio (NLR) ≥ 2.43 and α < 0.08 were statistically significant predictors of disease-specific survival (DSS) in the aggressive group (DSS-A), whereas α ≥ 0.08 was the only significant predictor of DSS in the non-aggressive group (DSS-NA). The 2.5-year DSS-A and 8-year DSS-NA rates of patients with α ≥ 0.08 and α < 0.08 were 86.7% and 73%, and 78.5% and 94.8% in the high-NLR group, respectively. In cohort 2, patients with both NLR < 2.7 and α ≥ 0.07 had a higher 2.5-year DSS rate than did those with either NLR ≥ 2.72 or α < 0.07. E2F8 and STX6 significantly correlated with ɑ and survival. The 2.5-year DSS rates in patients with E2F8 + STX6 (log2FC) < 0.2429 and ≥0.2429 were 100% and 77.2%, respectively. The exponential slope α can potentially distinguish between aggressive and non-aggressive courses in cervical cancer patients.

Comparative immunogenicity of an mRNA/LNP and a DNA vaccine targeting HIV gag conserved elements in macaques

Immunogenicity of HIV-1 mRNA vaccine regimens was analyzed in a non-human primate animal model. Rhesus macaques immunized with mRNA in lipid nanoparticle (mRNA/LNP) formulation expressing HIV-1 Gag and Gag conserved regions (CE) as immunogens developed robust, durable antibody responses but low adaptive T-cell responses. Augmentation of the dose resulted in modest increases in vaccine-induced cellular immunity, with no difference in humoral responses. The gag mRNA/lipid nanoparticle (LNP) vaccine provided suboptimal priming of T cell responses for a heterologous DNA booster vaccination regimen. In contrast, a single immunization with gag mRNA/LNP efficiently boosted both humoral and cellular responses in macaques previously primed by a gag DNA-based vaccine. These anamnestic cellular responses were mediated by activated CD8⁺ T cells with a phenotype of differentiated T-bet⁺ cytotoxic memory T lymphocytes. The heterologous prime/boost regimens combining DNA and mRNA/LNP vaccine modalities maximized vaccine-induced cellular and humoral immune responses. Analysis of cytokine responses revealed a transient systemic signature characterized by the release of type I interferon, IL-15 and IFN-related chemokines. The pro-inflammatory status induced by the mRNA/LNP vaccine was also characterized by IL-23 and IL-6, concomitant with the release of IL-17 family of cytokines. Overall, the strong boost of cellular and humoral immunity induced by the mRNA/LNP vaccine suggests that it could be useful as a prophylactic vaccine in heterologous prime/boost modality and in immune therapeutic interventions against HIV infection or other chronic human diseases.

Interleukin 15 in Cell-Based Cancer Immunotherapy

Cell-based cancer immunotherapy, such as chimeric antigen receptor (CAR) engineered T and natural killer (NK) cell therapies, has become a revolutionary new pillar in cancer treatment. Interleukin 15 (IL-15), a potent immunostimulatory cytokine that potentiates T and NK cell immune responses, has demonstrated the reliability and potency to potentially improve the therapeutic efficacy of current cell therapy. Structurally similar to interleukin 2 (IL-2), IL-15 supports the persistence of CD8⁺ memory T cells while inhibiting IL-2-induced T cell death that better maintains long-term anti-tumor immunity. In this review, we describe the biology of IL-15, studies on administrating IL-15 and/or its derivatives as immunotherapeutic agents, and IL-15-armored immune cells in adoptive cell therapy. We also discuss the advantages and challenges of incorporating IL-15 in cell-based immunotherapy and provide directions for future investigation.

Engineering interferons and interleukins for cancer immunotherapy

Cytokines are a class of potent immunoregulatory proteins that are secreted in response to various stimuli and act locally to regulate many aspects of human physiology and disease. Cytokines play important roles in cancer initiation, progression, and elimination, and thus, there is a long clinical history associated with the use of recombinant cytokines to treat cancer. However, the use of cytokines as therapeutics has been limited by cytokine pleiotropy, complex biology, poor drug-like properties, and severe dose-limiting toxicities. Nevertheless, cytokines are crucial mediators of innate and adaptive antitumor immunity and have the potential to enhance immunotherapeutic approaches to treat cancer. Development of immune checkpoint inhibitors and combination immunotherapies has reinvigorated interest in cytokines as therapeutics, and a variety of engineering approaches are emerging to improve the safety and effectiveness of cytokine immunotherapy. In this review we highlight recent advances in cytokine biology and engineering for cancer immunotherapy.

A very long-acting IL-15: implications for the immunotherapy of cancer

BACKGROUND

Interleukin-15 (IL-15) is an important cytokine necessary for proliferation and maintenance of natural killer (NK) and CD8+ T cells, and with great promise as an immuno-oncology therapeutic. However, IL-15 has a very short half-life and a single administration does not provide the sustained exposure required for optimal stimulation of target immune cells. The purpose of this work was to develop a very long-acting prodrug that would maintain IL-15 within a narrow therapeutic window for long periods-similar to a continuous infusion.

METHODS

We prepared and characterized hydrogel microspheres (MS) covalently attached to IL-15 (MS~IL-15) by a releasable linker. The pharmacokinetics and pharmacodynamics of MS~IL-15 were determined in C57BL/6J mice. The antitumor activity of MS~IL-15 as a single agent, and in combination with a suitable therapeutic antibody, was tested in a CD8+ T cell-driven bilateral transgenic adenocarcinoma mouse prostate (TRAMP)-C2 model of prostatic cancer and a NK cell-driven mouse xenograft model of human ATL (MET-1) murine model of adult T-cell leukemia.

RESULTS

On subcutaneous administration to mice, the cytokine released from the depot maintained a long half-life of about 168 hours over the first 5 days, followed by an abrupt decrease to about ~30 hours in accordance with the development of a cytokine sink. A single injection of MS~IL-15 caused remarkably prolonged expansions of NK and ɣδ T cells for 2 weeks, and CD44hiCD8+ T cells for 4 weeks. In the NK cell-driven MET-1 murine model of adult T-cell leukemia, single-agent MS~IL-1550 μg or anti-CCR4 provided modest increases in survival, but a combination-through antibody-depedent cellular cytotoxicity (ADCC)-significantly extended survival. In a CD8+ T cell-driven bilateral TRAMP-C2 model of prostatic cancer, single agent subcutaneous MS~IL-15 or unilateral intratumoral agonistic anti-CD40 showed modest growth inhibition, but the combination exhibited potent, prolonged bilateral antitumor activity.

CONCLUSIONS

Our results show MS~IL-15 provides a very long-acting IL-15 with low Cmax that elicits prolonged expansion of target immune cells and high anticancer activity, especially when administered in combination with a suitable immuno-oncology agent.

Phase I study of single agent NIZ985, a recombinant heterodimeric IL-15 agonist, in adult patients with metastatic or unresectable solid tumors

Background

NIZ985 is a recombinant heterodimer of physiologically active interleukin (IL-)15 and IL-15 receptor alpha. In preclinical models, NIZ985 promotes cytotoxic lymphocyte proliferation, killing function, and organ/tumor infiltration, with resultant anticancer effects. In this first-in-human study, we assessed the safety, pharmacokinetics, and immune effects of NIZ985 in patients with metastatic or unresectable solid tumors.

Methods

Single agent NIZ985 dose escalation data are reported from a phase I dose escalation/expansion study of NIZ985 as monotherapy. Adult patients (N=14) received 0.25, 0.5, 1, 2 or 4 µg/kg subcutaneous NIZ985 three times weekly (TIW) for the first 2 weeks of each 28-day cycle, in an accelerated 3+3 dose escalation trial design. IL-15 and endogenous cytokines were monitored by ELISA and multiplexed electrochemiluminescent assays. Multiparameter flow cytometry assessed the frequency, phenotype and proliferation of peripheral blood mononuclear cells. Preliminary antitumor activity was assessed by overall response rate (Response Evaluation Criteria in Solid Tumors V.1.1).

Results

As of March 2, 2020, median treatment duration was 7.5 weeks (range 1.1–77.1). Thirteen patients had discontinued and one (uveal melanoma) remains on treatment with stable disease. Best clinical response was stable disease (3 of 14 patients; 21%). The most frequent adverse events (AEs) were circular erythematous injection site reactions (100%), chills (71%), fatigue (57%), and fever (50%). Treatment-related grade 3/4 AEs occurred in six participants (43%); treatment-related serious AEs (SAEs) in three (21%). The per-protocol maximum tolerated dose was not reached. Pharmacokinetic accumulation of serum IL-15 in the first week was followed by significantly lower levels in week 2, likely due to more rapid cytokine consumption by an expanding lymphocyte pool. NIZ985 treatment was associated with increases in several cytokines, including interferon (IFN)-γ, IL-18, C-X-C motif chemokine ligand 10, and tumor necrosis factor-β, plus significant induction of cytotoxic lymphocyte proliferation (including natural killer and CD8⁺ T cells), increased CD16⁺ monocytes, and increased CD163⁺ macrophages at injection sites.

Conclusions

Subcutaneous NIZ985 TIW was generally well tolerated in patients with advanced cancer and produced immune activation paralleling preclinical observations, with induction of IFN-γ and proliferation of cytotoxic lymphocytes. Due to delayed SAEs at the two highest dose levels, administration is being changed to once-weekly in a revised protocol, as monotherapy and combined with checkpoint inhibitor spartalizumab. These alterations are expected to maximize the potential of NIZ985 as a novel immunotherapy.

Trial registration number

NCT02452268.

NK Cell Therapy: A Rising Star in Cancer Treatment

Simple Summary

A cancer treatment approach known as immunotherapy has become popular in the medical field. In this case, immune cells are boosted for effective response against cancer. A type of immune cell with significant potential for use in immunotherapy is the natural killer (NK) cell. The number of NK cells in the cancer tissues has been shown to be lower than normal, and this contributes to the growth of cancer cells. Besides, the immune function of the NK cells is compromised, thus interfering with anticancer immunity. Many research studies are being conducted to develop cancer treatment strategies based on increasing the number of NK cells and enhancing their activity.

Abstract

Immunotherapy has become a robust and routine treatment strategy for patients with cancer; however, there are efficacy and safety issues that should be resolved. Natural killer (NK) cells are important innate immune cells that have attracted increasing attention owing to their major histocompatibility complex-independent immunosurveillance ability. These cells provide the first-line defense against carcinogenesis and are closely related to cancer development. However, NK cells are functionally suppressed owing to multiple immunosuppressive factors in the tumor microenvironment; thus, releasing the suppressed state of NK cells is an emergent project and a promising solution for immunotherapy. As a result, many clinical trials of NK cell therapy alone or in combination with other agents are currently underway. This review describes the current status of NK cell therapy for cancer treatment based on the effector function and releasing the inhibited state of NK cells in the cancer microenvironment.

Systemic IL-15, IFN-γ, and IP-10/CXCL10 signature associated with effective immune response to SARS-CoV-2 in BNT162b2 mRNA vaccine recipients

Early responses to vaccination are important for shaping both humoral and cellular protective immunity. Dissecting innate vaccine signatures may predict immunogenicity to help optimize the efficacy of mRNA and other vaccine strategies. Here, we characterize the cytokine and chemokine responses to the 1^st and 2^nd dose of the BNT162b2 mRNA (Pfizer/BioNtech) vaccine in antigen-naive and in previously coronavirus disease 2019 (COVID-19)-infected individuals (NCT04743388). Transient increases in interleukin-15 (IL-15) and interferon gamma (IFN-γ) levels early after boost correlate with Spike antibody levels, supporting their use as biomarkers of effective humoral immunity development in response to vaccination. We identify a systemic signature including increases in IL-15, IFN-γ, and IP-10/CXCL10 after the 1^st vaccination, which were enriched by tumor necrosis factor alpha (TNF-α) and IL-6 after the 2^nd vaccination. In previously COVID-19-infected individuals, a single vaccination results in both strong cytokine induction and antibody titers similar to the ones observed upon booster vaccination in antigen-naive individuals, a result with potential implication for future public health recommendations.

Cell-based immunotherapy approaches for colorectal cancer: main achievements and challenges

Immunotherapy is becoming as a major treatment modality for multiple types of solid tumors, including subsets of colorectal cancers (CRCs). The successes with immunotherapy alone has largely been achieved in patients with advanced-stage mismatch-repair-deficient and microsatellite instability-high (dMMR-MSI-H) CRCs. However, the benefits of immunotherapy have not been demonstrated to be effective in patients with proficient mismatch repair (pMMR) CRC, who are microsatellite-stable (MSS) or have low levels of microsatellite instability (MSI-L). Here, we provide a comprehensive review on the immune microenvironment of CRC tumors and describe the rapid pace of scientific changes. We discuss the tremendous promise of cell-based immunotherapy strategies that are under preclinical studies/clinical trials or being used in therapeutic paradigms.