RESUMO
Dual blockade of the PD-1 and TIGIT coinhibitory receptors on T cells shows promising early results in cancer patients. Here, we studied the mechanisms whereby PD-1 and/or TIGIT blockade modulate anti-tumor CD8+ T cells. Although PD-1 and TIGIT are thought to regulate different costimulatory receptors (CD28 and CD226), effectiveness of PD-1 or TIGIT inhibition in preclinical tumor models was reduced in the absence of CD226. CD226 expression associated with clinical benefit in patients with non-small cell lung carcinoma (NSCLC) treated with anti-PD-L1 antibody atezolizumab. CD226 and CD28 were co-expressed on NSCLC infiltrating CD8+ T cells poised for expansion. Mechanistically, PD-1 inhibited phosphorylation of both CD226 and CD28 via its ITIM-containing intracellular domain (ICD); TIGIT's ICD was dispensable, with TIGIT restricting CD226 co-stimulation by blocking interaction with their common ligand PVR (CD155). Thus, full restoration of CD226 signaling, and optimal anti-tumor CD8+ T cell responses, requires blockade of TIGIT and PD-1, providing a mechanistic rationale for combinatorial targeting in the clinic.
Assuntos
Linfócitos T CD8-Positivos , Neoplasias , Antígenos de Diferenciação de Linfócitos T/metabolismo , Antígenos CD28/metabolismo , Humanos , Neoplasias/metabolismo , Receptor de Morte Celular Programada 1/metabolismo , Receptores Imunológicos/metabolismoRESUMO
Tiragolumab, an anti-TIGIT antibody with an active IgG1κ Fc, demonstrated improved outcomes in the phase 2 CITYSCAPE trial (ClinicalTrials.gov: NCT03563716 ) when combined with atezolizumab (anti-PD-L1) versus atezolizumab alone1. However, there remains little consensus on the mechanism(s) of response with this combination2. Here we find that a high baseline of intratumoural macrophages and regulatory T cells is associated with better outcomes in patients treated with atezolizumab plus tiragolumab but not with atezolizumab alone. Serum sample analysis revealed that macrophage activation is associated with a clinical benefit in patients who received the combination treatment. In mouse tumour models, tiragolumab surrogate antibodies inflamed tumour-associated macrophages, monocytes and dendritic cells through Fcγ receptors (FcγR), in turn driving anti-tumour CD8+ T cells from an exhausted effector-like state to a more memory-like state. These results reveal a mechanism of action through which TIGIT checkpoint inhibitors can remodel immunosuppressive tumour microenvironments, and suggest that FcγR engagement is an important consideration in anti-TIGIT antibody development.
Assuntos
Anticorpos Monoclonais , Antineoplásicos , Antígeno B7-H1 , Células Mieloides , Neoplasias , Receptores Imunológicos , Linfócitos T Reguladores , Animais , Humanos , Camundongos , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Antineoplásicos/uso terapêutico , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/imunologia , Linfócitos T CD8-Positivos/imunologia , Células Dendríticas/imunologia , Quimioterapia Combinada , Inibidores de Checkpoint Imunológico/imunologia , Inibidores de Checkpoint Imunológico/uso terapêutico , Ativação de Macrófagos , Células Mieloides/imunologia , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Receptores de IgG/imunologia , Receptores Imunológicos/imunologia , Linfócitos T Reguladores/imunologia , Microambiente Tumoral/imunologia , Macrófagos Associados a Tumor/imunologiaRESUMO
Despite the resounding clinical success in cancer treatment of antibodies that block the interaction of PD1 with its ligand PDL11, the mechanisms involved remain unknown. A major limitation to understanding the origin and fate of T cells in tumour immunity is the lack of quantitative information on the distribution of individual clonotypes of T cells in patients with cancer. Here, by performing deep single-cell sequencing of RNA and T cell receptors in patients with different types of cancer, we survey the profiles of various populations of T cells and T cell receptors in tumours, normal adjacent tissue, and peripheral blood. We find clear evidence of clonotypic expansion of effector-like T cells not only within the tumour but also in normal adjacent tissue. Patients with gene signatures of such clonotypic expansion respond best to anti-PDL1 therapy. Notably, expanded clonotypes found in the tumour and normal adjacent tissue can also typically be detected in peripheral blood, which suggests a convenient approach to patient identification. Analyses of our data together with several external datasets suggest that intratumoural T cells, especially in responsive patients, are replenished with fresh, non-exhausted replacement cells from sites outside the tumour, suggesting continued activity of the cancer immunity cycle in these patients, the acceleration of which may be associated with clinical response.
Assuntos
Linfócitos do Interstício Tumoral/citologia , Linfócitos do Interstício Tumoral/metabolismo , Neoplasias/patologia , Variantes Farmacogenômicos , Receptores de Antígenos de Linfócitos T/genética , Linfócitos T/citologia , Anticorpos Monoclonais Humanizados/uso terapêutico , Antineoplásicos/uso terapêutico , Células Clonais , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Linfócitos T/metabolismo , TranscriptomaRESUMO
BACKGROUND: Cancer immunotherapy approaches that elicit immune cell responses, including T and NK cells, have revolutionized the field of oncology. However, immunosuppressive mechanisms restrain immune cell activation within solid tumors so additional strategies to augment activity are required. METHODS: We identified the co-stimulatory receptor NKG2D as a target based on its expression on a large proportion of CD8+ tumor infiltrating lymphocytes (TILs) from breast cancer patient samples. Human and murine surrogate NKG2D co-stimulatory receptor-bispecifics (CRB) that bind NKG2D on NK and CD8+ T cells as well as HER2 on breast cancer cells (HER2-CRB) were developed as a proof of concept for targeting this signaling axis in vitro and in vivo. RESULTS: HER2-CRB enhanced NK cell activation and cytokine production when co-cultured with HER2 expressing breast cancer cell lines. HER2-CRB when combined with a T cell-dependent-bispecific (TDB) antibody that synthetically activates T cells by crosslinking CD3 to HER2 (HER2-TDB), enhanced T cell cytotoxicity, cytokine production and in vivo antitumor activity. A mouse surrogate HER2-CRB (mHER2-CRB) improved in vivo efficacy of HER2-TDB and augmented NK as well as T cell activation, cytokine production and effector CD8+ T cell differentiation. CONCLUSION: We demonstrate that targeting NKG2D with bispecific antibodies (BsAbs) is an effective approach to augment NK and CD8+ T cell antitumor immune responses. Given the large number of ongoing clinical trials leveraging NK and T cells for cancer immunotherapy, NKG2D-bispecifics have broad combinatorial potential.
Assuntos
Neoplasias da Mama , Linfócitos T CD8-Positivos , Células Matadoras Naturais , Subfamília K de Receptores Semelhantes a Lectina de Células NK , Humanos , Animais , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , Subfamília K de Receptores Semelhantes a Lectina de Células NK/imunologia , Camundongos , Linfócitos T CD8-Positivos/imunologia , Células Matadoras Naturais/imunologia , Feminino , Neoplasias da Mama/imunologia , Neoplasias da Mama/terapia , Receptor ErbB-2/imunologia , Linhagem Celular Tumoral , Imunoterapia/métodos , Ativação Linfocitária/imunologia , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismoRESUMO
BACKGROUND: ZED8 is a novel monovalent antibody labeled with zirconium-89 for the molecular imaging of CD8. This work describes nonclinical studies performed in part to provide rationale for and to inform expectations in the early clinical development of ZED8, such as in the studies outlined in clinical trial registry NCT04029181 [1]. METHODS: Surface plasmon resonance, X-ray crystallography, and flow cytometry were used to characterize the ZED8-CD8 binding interaction, its specificity, and its impact on T cell function. Immuno-PET with ZED8 was assessed in huCD8+ tumor-bearing mice and in non-human primates. Plasma antibody levels were measured by ELISA to determine pharmacokinetic parameters, and OLINDA 1.0 was used to estimate radiation dosimetry from image-derived biodistribution data. RESULTS: ZED8 selectively binds to human CD8α at a binding site approximately 9 Å from that of MHCI making mutual interference unlikely. The equilibrium dissociation constant (KD) is 5 nM. ZED8 binds to cynomolgus CD8 with reduced affinity (66 nM) but it has no measurable affinity for rat or mouse CD8. In a series of lymphoma xenografts, ZED8 imaging was able to identify different CD8 levels concordant with flow cytometry. In cynomolgus monkeys with tool compound 89Zr-aCD8v17, lymph nodes were conspicuous by imaging 24 h post-injection, and the pharmacokinetics suggested a flat-fixed first-in-human dose of 4 mg per subject. The whole-body effective dose for an adult human was estimated to be 0.48 mSv/MBq, comparable to existing 89Zr immuno-PET reagents. CONCLUSION: 89Zr immuno-PET with ZED8 appears to be a promising biomarker of tissue CD8 levels suitable for clinical evaluation in cancer patients eligible for immunotherapy.
Assuntos
Neoplasias , Tomografia por Emissão de Pósitrons , Adulto , Humanos , Camundongos , Ratos , Animais , Tomografia por Emissão de Pósitrons/métodos , Indicadores e Reagentes/uso terapêutico , Distribuição Tecidual , Neoplasias/terapia , Neoplasias/tratamento farmacológico , Imunoterapia/métodos , Zircônio/química , Linfócitos T CD8-Positivos/metabolismo , Linhagem Celular TumoralRESUMO
CD96 is a member of the poliovirus receptor (PVR, CD155)-nectin family that includes T cell Ig and ITIM domain (TIGIT) and CD226. While CD96, TIGIT, and CD226 have important roles in regulating NK cell activity, and TIGIT and CD226 have also been shown to regulate T cell responses, it is unclear whether CD96 has inhibitory or stimulatory function in CD8+ T cells. Here, we demonstrate that CD96 has co-stimulatory function on CD8+ T cells. Crosslinking of CD96 on human or mouse CD8+ T cells induced activation, effector cytokine production, and proliferation. CD96 was found to transduce its activating signal through the MEK-ERK pathway. CD96-mediated signaling led to increased frequencies of NUR77- and T-bet-expressing CD8+ T cells and enhanced cytotoxic effector activity, indicating that CD96 can modulate effector T cell differentiation. Antibody blockade of CD96 or genetic ablation of CD96 expression on CD8+ T cells impaired expression of transcription factors and proinflammatory cytokines associated with CD8+ T cell activation in in vivo models. Taken together, CD96 has a co-stimulatory role in CD8+ T cell activation and effector function.
Assuntos
Antígenos CD/imunologia , Linfócitos T CD8-Positivos/imunologia , Diferenciação Celular/imunologia , Ativação Linfocitária , Sistema de Sinalização das MAP Quinases/imunologia , Modelos Imunológicos , Animais , Antígenos CD/genética , Diferenciação Celular/genética , Linhagem Celular Tumoral , Humanos , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos KnockoutRESUMO
Here we have identified a surface protein, TIGIT, containing an immunoglobulin variable domain, a transmembrane domain and an immunoreceptor tyrosine-based inhibitory motif that was expressed on regulatory, memory and activated T cells. Poliovirus receptor, which is expressed on dendritic cells, bound TIGIT with high affinity. A TIGIT-Fc fusion protein inhibited T cell activation in vitro, and this was dependent on the presence of dendritic cells. The binding of poliovirus receptor to TIGIT on human dendritic cells enhanced the production of interleukin 10 and diminished the production of interleukin 12p40. Knockdown of TIGIT with small interfering RNA in human memory T cells did not affect T cell responses. TIGIT-Fc inhibited delayed-type hypersensitivity reactions in wild-type but not interleukin 10-deficient mice. Our data suggest that TIGIT exerts immunosuppressive effects by binding to poliovirus receptor and modulating cytokine production by dendritic cells.
Assuntos
Células Dendríticas/imunologia , Tolerância Imunológica , Proteínas de Membrana/metabolismo , Receptores Imunológicos/metabolismo , Linfócitos T/imunologia , Sequência de Aminoácidos , Animais , Células CHO , Comunicação Celular , Diferenciação Celular , Células Cultivadas , Cricetinae , Cricetulus , Células Dendríticas/citologia , Células Dendríticas/metabolismo , Regulação para Baixo , Humanos , Memória Imunológica , Interleucina-10/biossíntese , Subunidade p40 da Interleucina-12/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Ligação Proteica , Receptores Imunológicos/química , Receptores Imunológicos/genética , Receptores Virais/genética , Receptores Virais/metabolismo , Alinhamento de Sequência , Linfócitos T/metabolismoRESUMO
Receptors expressed on the plasma membrane and their interacting partners critically regulate cellular communication during homeostasis and disease, and as such represent main therapeutic targets. Despite its importance for drug development, receptor-ligand proteomics has remained a daunting field, in part because of the challenges associated to the study of membrane-expressed proteins. Here, to enable sensitive detection of receptor-ligand interactions in high throughput, we implement a new platform, the Conditioned Media AlphaScreen, for interrogation of a library consisting of most single transmembrane human proteins. Using this method to study key immune receptors, we identify and further validate the interleukin receptor IL20RA as the first binding partner for the checkpoint inhibitor B7-H3. Further, KIR2DL5, a natural killer cell protein that had remained orphan, is uncovered as a functional binding partner for the poliovirus receptor (PVR). This interaction is characterized using orthogonal assays, which demonstrate that PVR specifically engages KIR2DL5 on natural killer cells leading to inhibition of cytotoxicity. Altogether, these results reveal unappreciated links between protein families that may importantly influence receptor-driven functions during disease. Applicable to any target of interest, this technology represents a versatile and powerful approach for elucidation of receptor-ligand interactomes, which is essential to understand basic aspects of the biology of the plasma membrane proteins and ultimately inform the development of novel therapeutic strategies.
Assuntos
Antígenos B7/metabolismo , Matriz Extracelular/metabolismo , Células Matadoras Naturais/metabolismo , Receptores de Interleucina/metabolismo , Receptores KIR2DL5/metabolismo , Receptores Virais/metabolismo , Comunicação Celular , Células HEK293 , Humanos , Células Matadoras Naturais/citologia , Células Matadoras Naturais/imunologia , Ligantes , Ligação Proteica , Mapas de Interação de ProteínasRESUMO
Natural killer (NK) cell recognition of tumor cells is mediated through activating receptors such as CD226, with suppression of effector functions often controlled by negative regulatory transcription factors such as FOXO1. Here we show that CD226 regulation of NK cell cytotoxicity is facilitated through inactivation of FOXO1. Gene-expression analysis of NK cells isolated from syngeneic tumors grown in wild-type or CD226-deficient mice revealed dysregulated expression of FOXO1-regulated genes in the absence of CD226. In vitro cytotoxicity and stimulation assays demonstrated that CD226 is required for optimal killing of tumor target cells, with engagement of its ligand CD155 resulting in phosphorylation of FOXO1. CD226 deficiency or anti-CD226 antibody blockade impaired cytotoxicity with concomitant compromised inactivation of FOXO1. Furthermore, inhibitors of FOXO1 phosphorylation abrogated CD226-mediated signaling and effector responses. These results define a pathway by which CD226 exerts control of NK cell responses against tumors.
Assuntos
Antígenos de Diferenciação de Linfócitos T/metabolismo , Proteína Forkhead Box O1/antagonistas & inibidores , Proteína Forkhead Box O1/metabolismo , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Animais , Antígenos de Diferenciação de Linfócitos T/genética , Linhagem Celular Tumoral , Citotoxicidade Imunológica , Regulação Neoplásica da Expressão Gênica , Humanos , Ligantes , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Melanoma Experimental/genética , Melanoma Experimental/imunologia , Melanoma Experimental/metabolismo , Camundongos , Camundongos Knockout , Nectinas/metabolismo , Fosforilação , Receptores Virais/metabolismo , Transdução de Sinais/imunologiaRESUMO
Immunotherapies that harness the activity of the immune system against tumors are proving to be an effective therapeutic approach in multiple malignancies. Indeed, through accumulation of genetic mutations, many tumors express antigens that can potentially elicit specific tumor immunity. However, tumors can also suppress these responses by activating negative regulatory pathways and checkpoints such as PD-1/PD-L1 and CTLA-4. Blocking these checkpoints on T cells has provided dramatic clinical benefit, but only a subset of patients exhibit clear and durable responses, suggesting that other mechanisms must be limiting the immune response. We discuss here the role of TIGIT, an inhibitory receptor expressed by lymphocytes, in limiting antitumor responses and we review its mechanisms of action during the cancer immunity cycle.
Assuntos
Imunidade Celular , Imunoterapia/métodos , Neoplasias/imunologia , Receptores Imunológicos/metabolismo , Linfócitos T/imunologia , Animais , Anticorpos Monoclonais/uso terapêutico , Receptores Coestimuladores e Inibidores de Linfócitos T/imunologia , Receptores Coestimuladores e Inibidores de Linfócitos T/metabolismo , Humanos , Neoplasias/terapia , Receptores Imunológicos/imunologiaRESUMO
Covalent modification of histones is a fundamental mechanism of regulated gene expression in eukaryotes, and interpretation of histone modifications is an essential feature of epigenetic control. Bromodomains are specialized binding modules that interact with acetylated histones, linking chromatin recognition to gene transcription. Because of their ability to function in a domain-specific fashion, selective disruption of bromodomain:acetylated histone interactions with chemical probes serves as a powerful means for understanding biological processes regulated by these chromatin adaptors. Here we describe the discovery and characterization of potent and selective small molecule inhibitors for the bromodomains of CREBBP/EP300 that engage their target in cellular assays. We use these tools to demonstrate a critical role for CREBBP/EP300 bromodomains in regulatory T cell biology. Because regulatory T cell recruitment to tumors is a major mechanism of immune evasion by cancer cells, our data highlight the importance of CREBBP/EP300 bromodomain inhibition as a novel, small molecule-based approach for cancer immunotherapy.
Assuntos
Proteína de Ligação a CREB/antagonistas & inibidores , Proteína p300 Associada a E1A/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Linfócitos T Reguladores/efeitos dos fármacos , Acetilação/efeitos dos fármacos , Proteína de Ligação a CREB/química , Proteína de Ligação a CREB/metabolismo , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Células Cultivadas , Proteína p300 Associada a E1A/química , Proteína p300 Associada a E1A/metabolismo , Fatores de Transcrição Forkhead/metabolismo , Histonas/metabolismo , Humanos , Simulação de Acoplamento Molecular , Estrutura Terciária de Proteína/efeitos dos fármacos , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/metabolismo , Transcriptoma/efeitos dos fármacosRESUMO
The pharmacokinetic (PK) behavior of monoclonal antibodies in cynomolgus monkeys (cynos) is generally translatable to that in humans. Unfortunately, about 39% of the antibodies evaluated for PKs in cynos have fast nonspecific (or non-target-mediated) clearance (in-house data). An empirical model relating variable region (Fv) charge and hydrophobicity to cyno nonspecific clearance was developed to gauge the risk an antibody would have for fast nonspecific clearance in the monkey. The purpose of this study was to evaluate the predictability of this empirical model on cyno nonspecific clearance with antibodies specifically engineered to have either high or low Fv charge. These amino acid changes were made in the Fv region of two test antibodies, humAb4D5-8 and anti-lymphotoxin α. The humAb4D5-8 has a typical nonspecific clearance in cynos, and by making it more positively charged, the antibody acquires fast nonspecific clearance, and making it less positively charged did not impact its clearance. Anti-lymphotoxin α has fast nonspecific clearance in cynos, and making it more positively charged caused it to clear even faster, whereas making it less positively charged caused it to clear slower and within the typical range. These trends in clearance were also observed in two other preclinical species, mice and rats. The effect of modifying Fv charge on subcutaneous bioavailability was also examined, and in general bioavailability was inversely related to the direction of the Fv charge change. Thus, modifying Fv charge appears to impact antibody PKs, and the changes tended to correlate with those predicted by the empirical model.
Assuntos
Região Variável de Imunoglobulina/imunologia , Farmacocinética , Animais , Ensaio de Imunoadsorção Enzimática , Região Variável de Imunoglobulina/química , Macaca fascicularis , Medição de RiscoRESUMO
Homotrimeric TNF superfamily ligands signal by inducing trimers of their cognate receptors. As a biologically active heterotrimer, Lymphotoxin(LT)α1ß2 is unique in the TNF superfamily. How the three unique potential receptor-binding interfaces in LTα1ß2 trigger signaling via LTß Receptor (LTßR) resulting in lymphoid organogenesis and propagation of inflammatory signals is poorly understood. Here we show that LTα1ß2 possesses two binding sites for LTßR with distinct affinities and that dimerization of LTßR by LTα1ß2 is necessary and sufficient for signal transduction. The crystal structure of a complex formed by LTα1ß2, LTßR, and the fab fragment of an antibody that blocks LTßR activation reveals the lower affinity receptor-binding site. Mutations targeting each potential receptor-binding site in an engineered single-chain variant of LTα1ß2 reveal the high-affinity site. NF-κB reporter assays further validate that disruption of receptor interactions at either site is sufficient to prevent signaling via LTßR.
Assuntos
Citocinas/química , Heterotrímero de Linfotoxina alfa1 e beta2/metabolismo , Receptor beta de Linfotoxina/metabolismo , Complexos Multiproteicos/imunologia , Transdução de Sinais/imunologia , Cromatografia em Gel , Citocinas/imunologia , Dimerização , Humanos , Complexos Multiproteicos/metabolismoRESUMO
Insufficient quantity of functional T cells is a likely factor limiting clinical activity of T cell bispecific antibodies, especially in solid tumor indications. We hypothesized that XmAb24306 (efbalropendekin alfa), a lymphoproliferative interleukin (IL)-15/IL-15 receptor α (IL-15Rα) Fc-fusion protein, may potentiate the activity of T cell dependent (TDB) antibodies. Activation of human peripheral T cells by cevostamab, an anti-FcRH5/CD3 TDB, or anti-HER2/CD3 TDB resulted in upregulation of IL-2/15Rß (CD122) receptor subunit in nearly all CD8+ and majority of CD4+ T cells, suggesting that TDB treatment may sensitize T cells to the IL-15. XmAb24306 enhanced T cell bispecific antibody induced CD8+ and CD4+ T cell proliferation and expansion. In vitro combination of XmAb24306 with cevostamab or anti-HER2/CD3 TDB resulted in significant enhancement of tumor cell killing, which was reversed when T cell numbers were normalized, suggesting that T cell expansion is the main mechanism for the observed benefit. Pre-treatment of immune competent mice with a mouse-reactive surrogate of XmAb24306 (mIL-15-Fc) resulted in significant increase of T cells in blood, spleen and in tumors and converted transient anti-HER2/CD3 TDB responses to complete durable responses. In summary, our results support the hypothesis where the number of tumor infiltrating T cells is rate limiting for the activity of solid tumor targeting TDBs. Upregulation of CD122 by TDB treatment and the observed synergy with XmAb24306 and T cell bispecific antibodies supports clinical evaluation of this novel immunotherapy combination.
RESUMO
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 â¼1.0-4.1 days) compared to wild-type IL-15 (half-life â¼1.1 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.
RESUMO
IL-1R-associated kinases (IRAKs) are important mediators of MyD88-dependent signaling by the TLR/IL-1R superfamily and facilitate inflammatory responses. IRAK4 and IRAK1 function as active kinases and as scaffolds for protein-protein interactions. We report that although IRAK1/4 kinase activity is essential for human plasmacytoid dendritic cell (pDC) activation, it is dispensable in B, T, dendritic, and monocytic cells, which is in contrast with an essential active kinase role in comparable mouse cell types. An IRAK1/4 kinase inhibitor abrogated TLR7/9-induced IFN-α responses in both mouse and human pDCs, but other human immune cell populations activated via TLR7/9 or IL-1R were refractory to IRAK4 kinase inhibition. Gene ablation experiments using small interfering RNA demonstrated an essential scaffolding role for IRAK1 and IRAK4 in MyD88-dependent signaling. Finally, we demonstrate that autoimmune patient (systemic lupus erythematosus and rheumatoid arthritis) serum activates both pDC and B cells, but IRAK1/4 kinase inhibition affects only the pDC response, underscoring the differential IRAK1/4 functional requirements in human immune cells. These data reveal important species differences and elaborate cell type requirements for IRAK1/4 kinase activity.
Assuntos
Complexo Antígeno-Anticorpo/sangue , Artrite Reumatoide/imunologia , Artrite Reumatoide/patologia , Quinases Associadas a Receptores de Interleucina-1/fisiologia , Lúpus Eritematoso Sistêmico/imunologia , Lúpus Eritematoso Sistêmico/patologia , Animais , Artrite Reumatoide/enzimologia , Autoanticorpos/biossíntese , Autoanticorpos/sangue , Subpopulações de Linfócitos B/enzimologia , Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/patologia , Células Cultivadas , Células Dendríticas/enzimologia , Células Dendríticas/imunologia , Células Dendríticas/patologia , Feminino , Humanos , Interleucina-17/biossíntese , Interleucina-17/sangue , Lúpus Eritematoso Sistêmico/enzimologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Monócitos/enzimologia , Monócitos/imunologia , Monócitos/patologia , Transdução de Sinais/imunologia , Células Th1/enzimologia , Células Th1/imunologia , Receptor Toll-Like 9/fisiologiaRESUMO
XmAb24306 is a lymphoproliferative interleukin (IL)-15/IL-15 receptor α (IL-15Rα) Fc-fusion protein currently under clinical investigation as an immunotherapeutic agent for cancer treatment. XmAb24306 contains mutations in IL-15 that attenuate its affinity to the heterodimeric IL-15 receptor ßγ (IL-15R). We observe substantially prolonged pharmacokinetics (PK) (half-life â¼ 2.5 to 4.5 days) in single- and repeat-dose cynomolgus monkey (cyno) studies compared to wild-type IL-15 (half-life â¼ 1 hour), leading to increased exposure and enhanced and durable expansion of NK cells, CD8+ T cells and CD4-CD8- (double negative [DN]) T cells. Drug clearance varied with dose level and time post-dose, and PK exposure decreased upon repeated dosing, which we attribute to increased target-mediated drug disposition (TMDD) resulting from drug-induced lymphocyte expansion (i.e., pharmacodynamic (PD)-enhanced TMDD). We developed a quantitative systems pharmacology (QSP) model to quantify the complex PKPD behaviors due to the interactions of XmAb24306 with multiple cell types (CD8+, CD4+, DN T cells, and NK cells) in the peripheral blood (PB) and lymphoid tissues. The model, which includes nonspecific drug clearance, binding to and TMDD by IL15R differentially expressed on lymphocyte subsets, and resultant lymphocyte margination/migration out of PB, expansion in lymphoid tissues, and redistribution to the blood, successfully describes the systemic PK and lymphocyte kinetics observed in the cyno studies. Results suggest that after 3 doses of every-two-week (Q2W) doses up to 70 days, the relative contributions of each elimination pathway to XmAb24306 clearance are: DN T cells > NK cells > CD8+ T cells > nonspecific clearance > CD4+ T cells. Modeling suggests that observed cellular expansion in blood results from the influx of cells expanded by the drug in lymphoid tissues. The model is used to predict lymphoid tissue expansion and to simulate PK-PD for different dose regimens. Thus, the model provides insight into the mechanisms underlying the observed PK-PD behavior of an engineered cytokine and can serve as a framework for the rapid integration and analysis of data that emerges from ongoing clinical studies in cancer patients as single-agent or given in combination.