IBI379, a novel B cell maturation antigen/CD3 bispecific T-cell engager, displays high antitumor efficacy in preclinical models of multiple myeloma.

Multiple myeloma (MM) is a hematological malignancy that results from the malignant proliferation of plasma cells in the bone marrow. B cell maturation antigen (BCMA) is highly selectively expressed in malignant plasma cells and is a novel therapeutic target for MM. Here, we developed a bispecific T cell engager, IBI379, that targets BCMA and CD3, and investigated its antitumor efficacy against MM. IBI379 showed strong binding affinity with both BCMA and CD3, which triggered T cell activation, proliferation, and cytokine release. An in vitro study demonstrated that IBI379 induced the lysis of MM cells expressing differing levels of BCMA on the cell surface. Administration of IBI379 in H929 or Daudi-BCMA cell xenograft mouse models significantly inhibited tumor growth without inducing body weight loss. The mechanism of action study revealed the accumulation of CD4+CD8+ T cells and granzyme B-positive T cells in tumors that were treated with IBI379. Moreover, administration of low dose of IBI379 in cynomolgus monkeys was well-tolerated and induced the depletion of BCMA+ B cells and a mild transient increase of cytokines. Collectively, these results demonstrate that IBI379 is a highly potent therapeutic strategy for depleting BCMA-positive B cells and is a promising approach for the treatment of MM.

Combined strategies for effective cancer immunotherapy with a novel anti-CD47 monoclonal antibody.

CD47 is a widely expressed cell-surface protein that regulates phagocytosis mediated by cells of the innate immune system, such as macrophages and dendritic cells. CD47 serves as the ligand for a receptor on these innate immune cells, signal regulatory protein (SIRP)-α, which in turn inhibits phagocytosis. Several targeted CD47 therapeutic antibodies have been investigated clinically; however, how to improve its therapeutic efficacy remains unclear. Herein, we developed a CD47 blocking antibody, named IBI188, that could specifically block the CD47-SIRP-α axis, which transduces the "don't eat me" signal to macrophages. In vitro phagocytosis assays demonstrated the pro-phagocytosis ability of IBI188. Furthermore, several in vivo models were chosen to evaluate the anti-tumor efficacy of IBI188. IBI188 treatment upregulated cell movement- and inflammation-related genes in macrophages. Synergism was observed when combined with an anti-CD20 therapeutic antibody, whose function depends on antibody-dependent cellular cytotoxicity/phagocytosis (ADCC/ADCP). CD47 expression was evaluated following azacytidine (AZA) treatment, a standard-of-care for patients with multiple myeloma; enhanced anti-tumor efficacy was observed in the combination group in AML xenograft models. Notably, IBI188 treatment increased vascular endothelial growth factor-A (VEGF-A) levels in a solid tumor model, and combined treatment with an anti-VEGF-A antibody and IBI188 resulted in an enhanced anti-tumor effect. These data indicate that IBI188 is a therapeutic anti-CD47 antibody with anti-tumor potency, which can be enhanced when used in combination with standard-of-care drugs for cancer treatment.

PD-L1/LAG-3 bispecific antibody enhances tumor-specific immunity.

Anti-programmed cell death-1 (PD-1)/PD-ligand-1 (PD-L1) treatments are effective in a fraction of patients with advanced malignancies. However, the majority of patients do not respond to it. Resistance to cancer immunotherapy can be mediated by additional immune checkpoints. We hypothesized that co-targeting of PD-L1 and lymphocyte-activation gene 3 (LAG-3) could provide an alternative therapeutic approach. Here, we developed IBI323, a dual blockade bispecific antibody targeting PD-L1 and LAG-3. We assessed the binding affinity, blocking activity, cell bridging effect, and immunomodulation function of IBI323 using in vitro assays. We also evaluated, in two humanized mouse models, anti-tumor effects and antitumor T cell immunity induced by IBI323. IBI323 bound to PD-L1 and LAG-3 with similar potency as its parental antibodies and blocked the interaction of PD-1/PD-L1, CD80/PD-L1, and LAG-3/MHC-II. Moreover, IBI323 mediated the bridging of PD-L1+ cells and LAG-3+ cells and demonstrated superior immune stimulatory activity compared to each parent antibody in mixed leukocyte reaction. In PD-L1/LAG-3 double knock-in mice bearing human PD-L1 knock-in MC38 tumors, IBI323 showed stronger anti-tumor activity compared to each parental antibody. The better antitumor response correlated with increased tumor-specific CD8+ and CD4+ T cells. IBI323 also induced stronger anti-tumor effect against established A375 tumors compared with combination in mice reconstituted with human immune cells. Collectively, these data demonstrated that IBI323 preserved the blockade activities of parental antibodies while processing a novel cell bridging function. Based on the encouraging preclinical results, IBI323 has significant value in further clinical development.

Tumor-selective blockade of CD47 signaling with a CD47/PD-L1 bispecific antibody for enhanced anti-tumor activity and limited toxicity.

CD47, an immune checkpoint receptor frequently unregulated in various blood and solid tumors, interacts with ligand SIPRα on innate immune cells, and conveys a "do not eat me" signal to inhibit macrophage-mediated tumor phagocytosis. This makes CD47 a valuable target for cancer immunotherapy. However, the therapeutic utility of CD47-SIRPα blockade monoclonal antibodies is largely compromised due to significant red blood cell (RBCs) toxicities and fast target-mediated clearance as a result of extensive expression of CD47 on normal cells. To overcome these limitations and further improve therapeutic efficacy, we designed IBI322, a CD47/PD-L1 bispecific antibody which attenuated CD47 activity in monovalent binding and blocked PD-L1 activity in bivalent binding. IBI322 selectively bound to CD47+PD-L1+ tumor cells, effectively inhibited CD47-SIRPα signal and triggered strong tumor cell phagocytosis in vitro, but only with minimal impact on CD47 single positive cells such as human RBCs. In addition, as a dual blocker of innate and adaptive immune checkpoints, IBI322 effectively accumulated in PD-L1-positive tumors and demonstrated synergistic activity in inducing complete tumor regression in vivo. Furthermore, IBI322 showed only marginal RBCs depletion and was well tolerated in non-human primates (NHP) after repeated weekly injections, suggesting a sufficient therapeutic window in future clinical development of IBI322 for cancer treatment.

Development and characterization of a novel anti-OX40 antibody for potent immune activation.

With the great success of anti-CTLA-4 and anti-PD-1 therapeutics in cancer immunotherapy, tumor necrosis factor receptor superfamily members have been recognized as ideal targets to provide co-stimulatory signals in combination with immune checkpoint blocking antibodies. Among these is OX40 (CD134), a co-stimulatory molecule expressed by activated immune cells. Recently, several anti-OX40 agonistic monoclonal antibodies, pogalizumab as the most advanced, have entered early phase clinical trials. Using a yeast platform and multiple screening methods, we identified a fully human anti-OX40 antibody (IBI101) with distinct modes of action. Unlike pogalizumab, IBI101 partially blocks the binding of OX40 to its ligand OX40L and exhibits both FcγR-dependent and independent agonistic activities in NF-κB luciferase reporter assays. IBI101 also promotes T cell activation and proliferation in vitro. These unique properties partially explain the more potent anti-tumor activity of IBI101 than that of pogalizumab in humanized NOG mice bearing LoVo tumors. In addition, IBI101 shows efficacious anti-tumor activity in mice when administrated alone or in combination with anti-PD-1 antibodies. In human OX40 knock-in mice bearing MC38 colon carcinoma, IBI101 treatment induces tumor antigen-specific CD8+ T-cell responses, decreases immunosuppressive regulatory T cells in tumor, and enhances the immune response to PD-1 inhibition. Preclinical studies of IBI101 in non-human primates demonstrate typical pharmacokinetic characteristics of an IgG antibody and no drug-related toxicity. Collectively, IBI101 has desirable preclinical attributes which support its clinical development for cancer treatment.

A novel antibody targeting TIM-3 resulting in receptor internalization for cancer immunotherapy.

BACKGROUND: Strategies to reinvigorate exhausted T cells have achieved great efficacy in certain subpopulations of tumor patients. Blocking the antibodies that target programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 induces durable responses in Hodgkin's lymphoma, melanoma, renal and lung cancers. T cell immunoglobulin mucin-3 (TIM-3) is another well-defined inhibitory receptor that is expressed in terminally differentiated Th1/Tc1 cells, which produces interferon gamma and cytotoxic molecules. It is also significantly expressed on forkhead box P3+ regulatory T cells and innate immune cells such as dendritic cells and macrophages. METHODS: By immunizing BALB/c mice with recombinant TIM-3 and screening of 20 000 hybridoma clones, we selected a monoclonal TIM-3-blocking antibody (IBI104), which shows great efficacy in vitro and in vivo. RESULTS: IBI104 blocks phosphatidylserine interaction with TIM-3 but does not interfere with the interaction of TIM-3 with galectin-9 in ELISA assays. However, in vitro administration of IBI104 induces the potent internalization of TIM-3 in activated T cells to the extent that it will shut down the entire TIM-3 mediated signaling regardless of the ligands. IBI104 shows potent anti-tumor efficacy when combined with anti-PD1 in vivo. CONCLUSIONS: Our results suggest that IBI104 is a promising blocking antibody for TIM-3-mediated suppressive signaling and can serve as effective cancer immunotherapy, especially in combination with anti-PD1.

The prevalence, risk factors, and clinical characteristics of insulin resistance in Chinese patients with schizophrenia.

BACKGROUND: Studies have shown that patients with schizophrenia are at a high risk of developing insulin resistance (IR). We investigated the prevalence of IR and its clinical correlates in hospitalized Chinese patients with schizophrenia. METHODS: A total of 193 patients with schizophrenia (113 males and 80 females) were recruited for the study. We collected their demographic and clinical data, including data on their plasma glucose and lipid levels. All patients were rated using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) to assess cognitive function, while Positive and Negative Syndrome Scale (PANSS) was used to assess psychopathology. The cut-off value for the homeostasis model assessment of insulin resistance (HOMA-IR) was set at 1.7. RESULTS: The prevalence of IR was 37.82% (73/193). The IR patients had significantly higher waist-to-hip ratio and body mass index (BMI), and higher fasting plasma glucose (FPG), triglyceride (TG), and low density lipoprotein (LDL) levels compared to non-IR patients (all p<.05). Binary logistic regression analysis showed that smoking, BMI, and TG and LDL levels are significant predictors of IR. In addition, correlation analysis showed that IR was significantly correlated with the waist-to-hip ratio, BMI, and LDL level (Bonferroni corrected p<.05). The multivariable linear regression analysis indicated that the BMI and FPG are associated with the IR index. There was no significant difference in IR index between patients who were taking different antipsychotics. CONCLUSION: We found a high prevalence of IR and its risk factors in Chinese patients with schizophrenia. Active weight control to reduce the BMI and waist circumference and reducing the number of cigarettes consumed, may be essential to decrease the incidence of IR in patients with schizophrenia.

Durable blockade of PD-1 signaling links preclinical efficacy of sintilimab to its clinical benefit.

Blockade of immune checkpoint pathways by programmed cell death protein 1 (PD-1) antibodies has demonstrated broad clinical efficacy against a variety of malignancies. Sintilimab, a highly selective, fully human monoclonal antibody (mAb), blocks the interaction of PD-1 and its ligands and has demonstrated clinical benefit in various clinical studies. Here, we evaluated the affinity of sintilimab to human PD-1 by surface plasmon resonance and mesoscale discovery and evaluated PD-1 receptor occupancy and anti-tumor efficacy of sintilimab in a humanized NOD/Shi-scid-IL2rgamma (null) (NOG) mouse model. We also assessed the receptor occupancy and immunogenicity of sintilimab from clinical studies in humans (9 patients with advanced solid tumor and 381 patients from 4 clinical studies, respectively). Sintilimab bound to human PD-1 with greater affinity than nivolumab (Opdivo®, MDX-1106) and pembrolizumab (Keytruda®, MK-3475). The high affinity of sintilimab is explained by its distinct structural binding mode to PD-1. The pharmacokinetic behavior of sintilimab did not show any significant differences compared to the other two anti-PD-1 mAbs. In the humanized NOG mouse model, sintilimab showed superior PD-1 occupancy on circulating T cells and a stronger anti-tumor effect against NCI-H292 tumors. The strong anti-tumor response correlated with increased interferon-γ-secreting, tumor-specific CD8+ T cells, but not with CD4+ Tregs in tumor tissue. Pharmacodynamics testing indicated a sustained mean occupancy of ≥95% of PD-1 molecules on circulating T cells in patients following sintilimab infusion, regardless of infusion dose. Sintilimab infusion was associated with 0.52% (2/381 patients) of anti-drug antibodies and 0.26% (1/381 patients) neutralizing antibodies. These data validate sintilimab as a novel, safe, and efficacious anti-PD-1 mAb for cancer immunotherapy.