Therapeutic Antibody Targeting Research Articles

Effectiveness, safety and impact of guselkumab on sexuality and perceived stigmatization in patients with psoriasis in routine clinical practice: Week 28 results from the prospective German multicentre G-EPOSS study.

G-EPOSS is a prospective, non-interventional, German multicentre study of patients with moderate-to-severe plaque psoriasis receiving guselkumab, a therapeutic monoclonal antibody targeting interleukin-23, in a real-world setting. The objective of the study was to evaluate the effectiveness and safety of guselkumab, including its impact on skin, health-related quality of life (HRQoL), sexuality, and perceived stigmatization. Patients (≥18 years old) received guselkumab per routine clinical practice. The primary endpoint was the proportion of patients achieving absolute Psoriasis Area and Severity Index (PASI) ≤ 3 at Week (W)28. Secondary endpoint assessments over 28 weeks included the Nail Psoriasis Severity Index (NAPSI), anogenital Physician's Global Assessment (aPGA), and Dermatology Life Quality Index (DLQI). Sexuality and perceived stigmatization were assessed by patients using the Relationship and Sexuality Scale (RSS) and Perceived Stigmatization Questionnaire (PSQ), respectively. Overall, 293 patients were included in the evaluable set population. Mean age and disease duration were 45.6 and 17.6 years, respectively. At baseline, mean PASI, aPGA and DLQI scores were 15.3, 2.7 and 11.3, respectively. In total, 25.9% of patients had received a prior biologic. Overall, 83.0% of patients achieved PASI ≤ 3, and 56.2%/35.1% achieved PASI ≤ 1/PASI = 0, respectively, at W28. Among those with NAPSI ≥ 1 and aPGA ≥ 1 at baseline, NAPSI = 0 and aPGA = 0 were achieved by 39.2% and 61.1% of patients, respectively, and 61.4% of patients achieved DLQI 0-1 at W28. Improvements were observed over 28 weeks across individual items of the DLQI, RSS and PSQ, indicating improved HRQoL and sex life, and decreased perceived stigmatization. Based on DLQI Question (Q)9, 53.6% of patients experienced sexual difficulties at baseline, which decreased to 12.1% at W28. DLQI Q9 responses were consistent with RSS item responses, highlighting DLQI Q9 as a sentinel for sexual impairment. Guselkumab improved overall skin symptoms and HRQoL in patients with psoriasis and decreased sexual impairment and perceived stigmatization. No new safety signals were observed. CNTO1959PSO4008.

Abstract ND08: M3554, a novel anti-GD2 antibody drug conjugate

Abstract The glycosphingolipid GD2 is a cell membrane component of a limited number of normal tissues including nerve cells, melanocytes or lymphocytes. However, in some tumor types as neuroblastoma, osteosarcoma, glioma, or soft tissue sarcoma, GD2 is found on cell membranes with high levels. This tumor associated expression pattern makes GD2 an attractive target for therapeutic antibodies like dinutuximab (ch14.18) and naxitamab, which have been approved for neuroblastoma. M3554 is designed a be novel anti-GD2 ADC based on the humanized ch14.18 anti-GD2 antibody. The payload linker consists of the Topoisomerase I inhibitor (TOP1i) payload exatecan and a cleavable beta-glucuronide linker structure, which demonstrated higher potency, better bystander effects and improved activity in multidrug resistant cancer cells compared to other TOP1i payloads. While the antitumor effect of approved anti-GD2 antibodies is presumably related to Antibody-Dependent Cellular Cytotoxicity (ADCC) and Complement- Dependent Cytotoxicity (CDC), M3554 will exploit the high antigen density for direct tumor cytotoxicity by the payload. As the ADCC and CDC effector functions are believed to cause side effects for the approved GD2 antibodies, we have modified the M3554 antibody moiety with mutations in the Fc-region to reduce or eliminate these Fcγ receptor mediated functions. The cytotoxicity of M3554 was in the subnanomolar IC50 range for the GD2-positive neuroblastoma cell line CHP134. M3554 showed strong in vivo antitumor activity with tumor regressions in the CHP134 xenograft model and in patient-derived xenografts from neuroblastoma, osteosarcoma or glioma at doses ranging from 3 to 10 mg/kg. In addition, M3554 showed favorable pharmacokinetics in rats and monkeys, indicating a very stable linker-payload, and a favorable safety profile. In conclusion, M3554 represents a novel therapeutic approach for oncology indications with a high unmet medical need and high GD2 prevalence. Disclosures: Christiane Amendt, Christine Knuehl, Willem Sloot, Stanley Sweeney-Lasch, Joao NS Pereira, Julia Dotterweich, Hans-Henning Boehm and Jan Anderl are employees of the healthcare business of Merck KGaA, Darmstadt, Germany. Timothy Crandall is an employee of EMD Serono. Mira Toister-Achituv is an employee of Inter-Lab Ltd., Yavne, Israel, an affiliate of Merck KGaA, Darmstadt, Germany.Sponsor: This study was sponsored by the healthcare business of Merck KGaA, Darmstadt, Germany (CrossRef Funder ID: 10.13039/100009945). Citation Format: Christiane Amendt, Christine Knuehl, Timothy Crandall, Willem Sloot, Mira Toister-Achituv, Stanley Sweeney-Lasch, Joao NS Pereira, Julia Dotterweich, Hans_Henning Boehm, Jianguo Ma, Jan Anderl. M3554, a novel anti-GD2 antibody drug conjugate [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr ND08.

Abstract 2732: NB203: A Novel therapeutic bispecific antibody targeting CEACAM1/VEGF for tumor immunity and angiogenesis modulation in the tumor microenvironment

Abstract The carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1) is detected on leukocytes, epithelia and endothelia, and involved in cell adhesion through homophilic or heterophilic binding. In various gastrointestinal cancers, NSCLC (non-small cell lung cancer), and melanoma, CEACAM1 is highly expressed on tumor cells and tumor stroma, with its levels increasing as the disease progresses. Notably, CEACAM1 has been found to dampen T and NK cell functions while promoting tumor angiogenesis and metastasis. In this study, we present NB203, a novel CEACAM1/VEGF bispecific antibody developed using Neologics CEACAM-plus, a bifunctional molecule engineering platform designed to target and modulate the tumor microenvironment (TME). NB203 effectively accumulated in the TME and hindered the homophilic or heterophilic interactions of CEACAM1. It demonstrated a significant enhancement in T cell activities and NK cell-mediated killing of CEACAM1-expressing tumor cells, and the inhibition of tumor cell migration and polyploidy through macrophages. More importantly, NB203 was specifically designed to impede tumor angiogenesis. It exhibited an increased binding capacity to both CEACAM1 and VEGF in pro-angiogenic TME, and undermined intratumoral vessel maturation by blocking VEGF and negatively regulating myeloid cell-dependent tumor angiogenesis. In summary, our preclinical data indicate that NB203 exhibits effective anti-tumor activity by mediating NK and cytotoxic T cell activities, improving the immune-suppressive TME, and suppressing tumor angiogenesis. The use of NB203 holds promise in overcoming resistance to anti-VEGF therapy and substantially improving the safety of therapeutic targeting of angiogenesis in cancer treatment. Citation Format: Jinyu Dong, Binbin Wang, Dong Wang, Jie Ni, Tingting Bu, Haojie Wang, Bishnu Nayak, Baiyang Wang, Xin Dong, Yu Zhang. NB203: A Novel therapeutic bispecific antibody targeting CEACAM1/VEGF for tumor immunity and angiogenesis modulation in the tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2732.

Abstract 718: CCR8 antibody drug conjugates: Targeting regulatory T cells for tumor sensitization

Abstract Background: Regulatory T (Treg) cells in the tumor microenvironment have an immune suppressive function, and their presence is associated with poor prognosis. Depletion of Treg cells may be a mechanism to sensitize tumors and represents a novel strategy for cancer immunotherapy. High expression of chemokine receptor CCR8 has been found in Treg cells in microenvironments of numerous tumors but not on Treg cells in systemic lymphoid tissues. The ability to selectively kill Treg cells in tumor environments may provide an opportunity for therapy that leaves Treg function intact elsewhere in the body where they normally mediate tolerance to self-antigen. Methods: We sought to identify CCR8 antibodies for therapeutics and designed an antibody discovery strategy to address the challenges of this target. CCR8 is a member of the G protein-coupled receptor (GPCR) family. Like many GPCRs, CCR8 is a valuable therapeutic antibody target but challenging to access due to its poor expression, membrane-dependent structure, and poor immunogenicity due to sequence conservation. We developed an antibody discovery platform (MPS) that specifically addresses each of these challenges through use of advanced immunization techniques and evolutionarily divergent host species (chickens) for robust immune responses against conserved targets. We extensively engineered CCR8 antigen to enable high expression for immunization. When sufficient antibody diversity was not obtained using our standard immunization techniques, we developed mRNA immunization techniques for this program. Antibody binding was measured using flow cytometry on transfected cells and human Treg cells. The ability of antibodies to inhibit CCR8 function was measured using intracellular calcium influx assays. Antibody internalization was measured using dye uptake assays and flow cytometry. Antibodies were conjugated with cytotoxic payloads and tested for the ability to mediate killing. Results: Using these approaches, we identified a panel of high-affinity antibodies that bound in the nanomolar or subnanomolar range with high specificity, and we selected a lead molecule to progress. We will present data from our antibody discovery campaign including mRNA immunization, binding profiles, GPCR functional data, receptor-mediated internalization, and the ability of antibody-drug conjugates (ADC) to kill CCR8+ cells, including human Treg cells, in vitro. Conclusion: Treg cells are a primary driver of the immunosuppressive microenvironment in many solid tumors. Targeting immune-suppressive CCR8+ Treg cells using ADC has potential to expand the treatment of solid tumors Citation Format: Lewis J. Stafford, Hayley Roth, Sarah Campbell, Samantha Brady, Valerie Fiers, FeiFan Yu, Andrew Tsourkas, Riley Payne, Meghan Pitts, Kyle Guldner, Tim Phillips, Breanna Tyrell, Colleen Ulke, Allison Snyder, Marianne Assogba, Holden Ohl, Ileine Sanchez, Benjamin Doranz, Joseph Rucker, Ross Chambers. CCR8 antibody drug conjugates: Targeting regulatory T cells for tumor sensitization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 718.

Modern approaches to the immunotherapy of <i>Clostridioides difficile</i>

Clostridioides difficile is a leading cause of diarrhea and pseudomembranous colitis associated with antibiotic therapy. Hypervirulent strains of C. difficile, such as ribotype 027, have high mortality rates. Recurrent C. difficile infection is extremely difficult to treat. Symptoms of the disease are caused by two toxins, TcdA and TcdB. These toxins are targets for therapeutic antibodies. The TcdB-specific monoclonal antibody bezlotoxumab (Zinplava ©, Merck & Co. Inc., USA), approved for the prevention of recurrent C. difficile infection, has some effectiveness against a limited set of C. difficile strains. Having a lower cost compared to monoclonal antibodies, high affinity for the antigen, and unique structural and functional properties, nanoantibodies are a promising strategy for the immunotherapy of diseases associated with C. difficile.

A therapeutic antibody targeting annexin-A1 inhibits cancer cell growth in vitro and in vivo

In this study we conducted the first investigation to assess the efficacy of a novel therapeutic antibody developed to target annexin-A1 (ANXA1). ANXA1 is an immunomodulatory protein which has been shown to be overexpressed in, and promote the development and progression of, several cancer types. In particular, high ANXA1 expression levels correlate with poorer overall survival in pancreatic and triple-negative breast cancers, two cancers with considerable unmet clinical need. MDX-124 is a humanised IgG1 monoclonal antibody which specifically binds to ANXA1 disrupting its interaction with formyl peptide receptors 1 and 2 (FPR1/2). Here we show that MDX-124 significantly reduced proliferation (p < 0.013) in a dose-dependent manner across a panel of human cancer cell lines expressing ANXA1. The anti-proliferative effect of MDX-124 is instigated by arresting cell cycle progression with cancer cells accumulating in the G1 phase of the cell cycle. Furthermore, MDX-124 significantly inhibited tumour growth in both the 4T1-luc triple-negative breast and Pan02 pancreatic cancer syngeneic mouse models (p < 0.0001). These findings suggest ANXA1-targeted therapy is a viable and innovative approach to treat tumours which overexpress ANXA1.

Nicotinamide-Expanded Allogeneic Natural Killer Cells with CD38 Deletion, Expressing an Enhanced CD38 Chimeric Antigen Receptor, Target Multiple Myeloma Cells.

Natural killer (NK) cells are a vital component of cancer immune surveillance. They provide a rapid and potent immune response, including direct cytotoxicity and mobilization of the immune system, without the need for antigen processing and presentation. NK cells may also be better tolerated than T cell therapy approaches and are susceptible to various gene manipulations. Therefore, NK cells have become the focus of extensive translational research. Gamida Cell's nicotinamide (NAM) platform for cultured NK cells provides an opportunity to enhance the therapeutic potential of NK cells. CD38 is an ectoenzyme ubiquitously expressed on the surface of various hematologic cells, including multiple myeloma (MM). It has been selected as a lead target for numerous monoclonal therapeutic antibodies against MM. Monoclonal antibodies target CD38, resulting in the lysis of MM plasma cells through various antibody-mediated mechanisms such as antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity, and antibody-dependent cellular phagocytosis, significantly improving the outcomes of patients with relapsed or refractory MM. However, this therapeutic strategy has inherent limitations, such as the anti-CD38-induced depletion of CD38-expressing NK cells, thus hindering ADCC. We have developed genetically engineered NK cells tailored to treat MM, in which CD38 was knocked-out using CRISPR-Cas9 technology and an enhanced chimeric antigen receptor (CAR) targeting CD38 was introduced using mRNA electroporation. This combined genetic approach allows for an improved cytotoxic activity directed against CD38-expressing MM cells without self-inflicted NK-cell-mediated fratricide. Preliminary results show near-complete abolition of fratricide with a 24-fold reduction in self-lysis from 19% in mock-transfected and untreated NK cells to 0.8% of self-lysis in CD38 knock-out CAR NK cells. Furthermore, we have observed significant enhancements in CD38-mediated activity in vitro, resulting in increased lysis of MM target cell lines. CD38 knock-out CAR NK cells also demonstrated significantly higher levels of NK activation markers in co-cultures with both untreated and αCD38-treated MM cell lines. These NAM-cultured NK cells with the combined genetic approach of CD38 knockout and addition of CD38 CAR represent a promising immunotherapeutic tool to target MM.

Human monoclonal antibodies inhibit invasion of transgenic Plasmodium knowlesi expressing Plasmodium vivax Duffy binding protein

BackgroundPlasmodium vivax has been more resistant to various control measures than Plasmodium falciparum malaria because of its greater transmissibility and ability to produce latent parasite forms. Therefore, developing P. vivax vaccines and therapeutic monoclonal antibodies (humAbs) remains a high priority. The Duffy antigen receptor for chemokines (DARC) expressed on erythrocytes is central to P. vivax invasion of reticulocytes. P. vivax expresses a Duffy binding protein (PvDBP) on merozoites, a DARC ligand, and the DARC: PvDBP interaction is critical for P. vivax blood stage malaria. Therefore, PvDBP is a leading vaccine candidate for P. vivax and a target for therapeutic human monoclonal antibodies (humAbs).MethodsHere, the functional activity of humAbs derived from naturally exposed and vaccinated individuals are compared for the first time using easily cultured Plasmodium knowlesi (P. knowlesi) that had been genetically modified to replace its endogenous PkDBP orthologue with PvDBP to create a transgenic parasite, PkPvDBPOR. This transgenic parasite requires DARC to invade human erythrocytes but is not reticulocyte restricted. This model was used to evaluate the invasion inhibition potential of 12 humAbs (9 naturally acquired; 3 vaccine-induced) targeting PvDBP individually and in combinations using growth inhibition assays (GIAs).ResultsThe PvDBP-specific humAbs demonstrated 70–100% inhibition of PkPvDBPOR invasion with the IC50 values ranging from 51 to 338 µg/mL for the 9 naturally acquired (NA) humAbs and 33 to 99 µg/ml for the 3 vaccine-induced (VI) humAbs. To evaluate antagonistic, additive, or synergistic effects, six pairwise combinations were performed using select humAbs. Of these combinations tested, one NA/NA (099100/094083) combination demonstrated relatively strong additive inhibition between 10 and 100 µg/mL; all combinations of NA and VI humAbs showed additive inhibition at concentrations below 25 µg/mL and antagonism at higher concentrations. None of the humAb combinations showed synergy. Invasion inhibition efficacy by some mAbs shown with PkPvDBPOR was closely replicated using P. vivax clinical isolates.ConclusionThe PkPvDBPOR transgenic model is a robust surrogate of P. vivax to assess invasion and growth inhibition of human monoclonal Abs recognizing PvDBP individually and in combination. There was no synergistic interaction for growth inhibition with the humAbs tested here that target different epitopes or subdomains of PvDBP, suggesting little benefit in clinical trials using combinations of these humAbs.

A Single Phenotypic Biomarker of Gemtuzumab Ozogamicin (GO) Response in Acute Myeloid Leukemia Using Ex-Vivo Testing

Background or Introduction: Gemtuzumab Ozogamicin (GO), a therapeutic antibody targeting CD33, gained FDA approval in 2017 for the treatment of patients with Acute Myeloid Leukemia (AML). Biomarkers to predict GO response were historically based on multiple indicators: CD33 expression levels, favorable cytogenetics and specific genetic alterations (NPM1, FLT3-internal tandem duplications, other mutations). Moreover, comprehensive analyses including stemness expression (LSC17 score) and molecularly derived scores such as the CD33_PGx6_Score (a composite score derived from six CD33 SNP of prognostic significance) have further refined the biomarkers to identify potential responders (Fenwarth et al, nt. J. Mol. Sci. 2020, 21, 5626). However, due to its toxicity profile and elevated cost, the identification of robust biomarkers of GO response in AML remains a challenge to optimize its therapeutic efficacy and worldwide clinical adoption. Methods: In this study, we utilized an innovative ex-vivo functional platform of Patient Micro Avatars (PMAs) developed at OncoPrecision (García et al, Blood 2022 140 (Supplement 1): 13027-13028) to assess the response to GO in a small cohort of AML patients. Patient-Derived Cells (PDCs) were obtained from five newly diagnosed AML patients and GO activity was assessed using high-throughput flow cytometry. The correlation between CD33 expression and the ex-vivo response to GO was also examined. Results: Our findings revealed a clear differential response to GO in AML patients, with contrasting outcomes observed within a dose-range that does not exceed its theoretical plasma concentration (Figure - Upper Panel). Interestingly, despite significant variations in CD33 expression levels among the evaluated patients, no obvious association was found between CD33 expression and the ex-vivo response to GO (Figure - Lower Panel). Conclusions: This study presents an innovative approach with the potential to predict GO responders versus non-responders in AML. A single phenotypic biomarker overcomes the need to determine CD33 expression levels in each patient or to assess the presence of specific polymorphic variants, as well as additional molecular biomarkers. Patient Micro Avatars present a compelling alternative to comprehensively identify patients who are most likely to benefit from GO treatment.

Targeting amyotrophic lateral sclerosis by neutralizing seeding-competent TDP-43 in CSF.

In amyotrophic lateral sclerosis, a disease driven by abnormal transactive response DNA-binding protein of 43 kDa aggregation, CSF may contain pathological species of transactive response DNA-binding protein of 43 kDa contributing to the propagation of pathology and neuronal toxicity. These species, released in part by degenerating neurons, would act as a template for the aggregation of physiological protein contributing to the spread of pathology in the brain and spinal cord. In this study, a robust seed amplification assay was established to assess the presence of seeding-competent transactive response DNA-binding protein of 43 kDa species in CSF of apparently sporadic amyotrophic lateral sclerosis patients. These samples resulted in a significant acceleration of substrate aggregation differentiating the kinetics from healthy controls. In parallel, a second assay was developed to determine the level of target engagement that would be necessary to neutralize such species in human CSF by a therapeutic monoclonal antibody targeting transactive response DNA-binding protein of 43 kDa. For this, evaluation of the pharmacokinetic/pharmacodynamic effect for the monoclonal antibody, ACI-5891.9, in vivo and in vitro confirmed that a CSF concentration of ≍1100 ng/mL would be sufficient for sustained target saturation. Using this concentration in the seed amplification assay, ACI-5891.9 was able to neutralize the transactive response DNA-binding protein of 43 kDa pathogenic seeds derived from amyotrophic lateral sclerosis patient CSF. This translational work adds to the evidence of transmission of transactive response DNA-binding protein of 43 kDa pathology via CSF that could contribute to the non-contiguous pattern of clinical manifestations observed in amyotrophic lateral sclerosis and demonstrates the ability of a therapeutic monoclonal antibody to neutralize the toxic, extracellular seeding-competent transactive response DNA-binding protein of 43 kDa species in the CSF of apparently sporadic amyotrophic lateral sclerosis patients.

Capturing the Functional Antibody Repertoire from Multiple B-cell Subsets Following Antigen Stimulation.

Abstract Antigen stimulation of mature B-cells induces activated B-cells followed by differentiation to either memory B-cells or plasmablasts. Each subset has a unique phenotype and potentially unique immunoglobulin repertoire that can be mined for therapeutic antibody candidates. As new targets for therapeutic antibodies have become more challenging, primary B-cell technologies have arisen to meet this challenge, but, their use has typically been limited to one of the B-cell subsets. We sought to develop a platform that could be used generally to interrogate all of the B-cell subsets (i.e., activated, memory and plasmablasts) that are potential sources of useful antibodies. Using fluorescence activated cell sorting (FACS), we have identified and sorted antigen-specific activated and memory B-cells by staining for CD19, surface IgG, and fluorochrome-tagged antigen. Antigen-specific plasmablasts have been identified and sorted after encapsulation of cells in microdroplets, capture of secreted IgG, CD19/CD138 staining, and fluorochrome-tagged antigen staining. Additionally, hybridomas have been evaluated using either protocol. The sorted cells have been sequenced by next generation sequencing (NGS) of paired heavy and light chains. With this platform ~10,000–20,000 antigen specific B-cells from a population of a few million viable lymphocytes have been sorted in 1–2 hours. From the sorted population, 100 – 700 unique paired clonotypes have been identified using this platform. The platform enables the capture of immunoglobulin repertoires from multiple B-cell subsets that is comprehensive, flexible, and cost-effective.

Characterization of a novel therapeutic antibody targeting peptide/HLA-E

Abstract T-cell receptor mimic antibodies (TCRm) have become an attractive therapeutic modality group as they allow for the targeting of intracellular proteins presented by HLA, which may allow for a large potential of new targets. However, the polymorphic nature of classical HLA class I and findings of HLA downregulation in cancer cells might limit the use of these agents for cancer treatment. An alternative approach would be to target peptides presented by HLA-E, a highly monomorphic molecule often found upregulated in cancer cells. Thus, we aimed to generate a TCRm against HLA-E presenting the leader sequence peptide from HLA-G since both HLAs are often expressed in multiple cancer types. An antibody was identified from a naïve human phage library and further affinity matured using yeast display. The final clone, ABX-001, had an affinity constant (K D) of 7.9nM. Specificity studies using both peptide-loaded cells and tumor cell lines showed that ABX-001 only bound when both HLA-E and HLA-G were present. Extensive profiling was done on immune cells to also confirm that they did not bind ABX-001. Finally, ABX-001 was assessed for its ability to direct killing of target-positive tumor cell lines. We observed that cytotoxicity in CD8 +T cells was enhanced with the addition of an ABX-001-CD3 T cell engager. We also observed that ABX-001 can act as a checkpoint inhibitor by blocking the interaction of HLA-E with NKG2A in cytotoxicity experiments using NK cells. These data indicate that we can effectively target peptide/HLA-E and highlights its potential therapeutic applications in cancer treatment.

CCR6 as a Potential Target for Therapeutic Antibodies for the Treatment of Inflammatory Diseases.

The CC chemokine receptor 6 (CCR6) is a G protein-coupled receptor (GPCR) involved in a wide range of biological processes. When CCR6 binds to its sole ligand CCL20, a signaling network is produced. This pathway is implicated in mechanisms related to many diseases, such as cancer, psoriasis, multiple sclerosis, HIV infection or rheumatoid arthritis. The CCR6/CCL20 axis plays a fundamental role in immune homeostasis and activation. Th17 cells express the CCR6 receptor and inflammatory cytokines, including IL-17, IL-21 and IL-22, which are involved in the spread of inflammatory response. The CCL20/CCR6 mechanism plays a crucial role in the recruitment of these pro-inflammatory cells to local tissues. To date, there are no drugs against CCR6 approved, and the development of small molecules against CCR6 is complicated due to the difficulty in screenings. This review highlights the potential as a therapeutic target of the CCR6 receptor in numerous diseases and the importance of the development of antibodies against CCR6 that could be a promising alternative to small molecules in the treatment of CCR6/CCL20 axis-related pathologies.

Abstract 6366: NB002, a novel therapeutic antibody targeting unique epitope on TIM-3 presenting potent antitumor activity

Abstract Antibody-based Immune checkpoint inhibitor (ICI) therapies targeting cytotoxic T lymphocyte antigen-4 (CTLA-4) or programmed death receptor-1 (PD-1) have significantly improved clinical outcomes in cancer treatment. Nonetheless, a large portion of the population has limited benefit from these ICI treatments due to lack of efficacy, resistance and intolerance. T-cell immunoglobulin and mucin domain containing-3 (TIM-3) has been proposed as a target for cancer immunotherapy. It is an inhibitory receptor modulating immune tolerance, and its expression has been broadly reported to be closely correlated to T cell exhaustion and pessimistic prognosis. Besides negatively modulating T cell status, TIM-3 is also expressed on natural killer (NK) cells, dendritic cells (DCs), macrophages and regulates immune responses bridging innate immunity and adaptive immunity. NB002 is a novel humanized Fc-engineered IgG1κ antibody, developed via NeologicsBio’s integrated target validation &amp; antibody screening Tier-A platform. It has been characterized in a serial of function and efficacy studies and completed IND-enabling preclinical development. NB002 binds to human TIM3 with high affinity in the low nanomolar range and antagonize the TIM-3 pathway effectively in reporter cell and primary cell assays. NB002 increased the secretion of IFN-γ by activated PBMC cells and enhanced activation and killing activity of NK cells. Moreover, it exhibited a distinctive activity of restoring myeloid cells and enhancing antigen presentation and processing during anti-tumor immune responses, and superior efficacy in multiple humanized mouse models of cancer as monotherapy regimen. Importantly, X-ray crystallography demonstrated that NB002 recognized a unique epitope on TIM-3 and was confirmed by epitope binning assay and structural alignment. These data could potentially explain novel features of NB002, restoring both acquired and innate immunity which could lead cold tumor to hot tumor.In summary, these data showed that NB002 is a potent anti-TIM-3 antibody with pre-clinical properties. A phase 1 study is planned and patients with advanced metastatic solid tumors will be recruited. Citation Format: Yu Zhang, Jinyu Dong, Binbin Wang, Jie Ni, Dong Wang, Liegang Shao, Meiguang Xiong, Ting Wang, Florencia McAllister, Xin Dong. NB002, a novel therapeutic antibody targeting unique epitope on TIM-3 presenting potent antitumor activity. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6366.

Abstract 561: Development of competing and non-competing fully human internalizing anti-Her2 monoclonal antibodies

Abstract The human epidermal growth factor receptor (HER) family of receptors has been implicated in several human cancers. Among them, HER2 is overexpressed in several cancers with or without gene amplification with prognostic and predictive implications. In 15-30% of breast cancers, HER2 overexpression and amplification are associated with shorter disease-free and overall survivals along with resistance to hormonal agents as well as increased risk of brain metastasis. Two types of HER2 targeting have been developed: anti-HER2 monoclonal antibodies and small molecule tyrosine kinase inhibitors. Trastuzumab is a humanized anti-HER2 monoclonal antibody that binds to domain IV of HER2 extracellular segment and blocks its signaling. It is the first therapeutic antibody targeting Her2 overexpression approved by the FDA. More recently, two antibody drug conjugates using trastuzumab have been approved: Ado-Trastuzumab-Emtansine (Kadcyla) consisting of trastuzumab conjugated to the drug mertansine DM1 and fam-trastuzumab-deruxtecan-nhki (Enhertu to deliver the topoisomerase inhibitor deruxtecan. We are reporting here the development of fully human internalizing anti-Her2 antibodies that compete or not with trastuzumab for binding to Her2. These antibodies have been developed by immunizing fully human (TC-Mab mouse) mice with recombinant Her2 protein. After production of hybridoma secreting fully human immunoglobulins, the screening process included inhibition of binding of trastuzumab to Her2 by enzyme linked immunoassay and by Octet epitope binning as well as internalization assay. Several internalizing antibodies able to compete or not with trastuzumab and with high affinity (Kd ranging from 10−9 M to 10−12 M) were selected. They were next investigated for their ability to deliver a cytotoxic payload in HER2 overexpressing cells breast cancer cells such as SKBR3, BT474 and AU565. Two antibodies: one competing with trastuzumab and the other one non-competing were further characterized. Data related to these antibodies’ biochemical characteristics as well as their ability to inhibit proliferation in vitro and in vivo in mouse xenografts studies will be presented here. In conclusion, the use of fully human mice in our laboratory provides a powerful and attractive approach to develop fully human monoclonal antibodies against cancer targets allowing to by-pass the need for humanization and affinity maturation of antibodies. Citation Format: Ginette Serrero, Binbin Yue, Jianping Dong, Chun Dong, Jun Hayashi. Development of competing and non-competing fully human internalizing anti-Her2 monoclonal antibodies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 561.

Development of an inhibiting antibody against equine interleukin 5 to treat insect bite hypersensitivity of horses

Insect bite hypersensitivity (IBH) is the most common allergic skin disease of horses. It is caused by insect bites of the Culicoides spp. which mediate a type I/IVb allergy with strong involvement of eosinophil cells. No specific treatment option is available so far. One concept could be the use of a therapeutic antibody targeting equine interleukin 5, the main activator and regulator of eosinophils. Therefore, antibodies were selected by phage display using the naïve human antibody gene libraries HAL9/10, tested in a cellular in vitro inhibition assay and subjected to an in vitro affinity maturation. In total, 28 antibodies were selected by phage display out of which eleven have been found to be inhibiting in the final format as chimeric immunoglobulin G with equine constant domains. The two most promising candidates were further improved by in vitro affinity maturation up to factor 2.5 regarding their binding activity and up to factor 2.0 regarding their inhibition effect. The final antibody named NOL226-2-D10 showed a strong inhibition of the interleukin 5 binding to its receptor (IC50 = 4 nM). Furthermore, a nanomolar binding activity (EC50 = 8.8 nM), stable behavior and satisfactory producibility were demonstrated. This antibody is an excellent candidate for in vivo studies for the treatment of equine IBH.

Immunogenicity of adjuvanted plant-produced SARS-CoV-2 Beta spike VLP vaccine in New Zealand white rabbits.

The outbreak of the SARS-CoV-2 global pandemic heightened the pace of vaccine development with various vaccines being approved for human use in a span of 24months. The SARS-CoV-2 trimeric spike (S) surface glycoprotein, which mediates viral entry by binding to ACE2, is a key target for vaccines and therapeutic antibodies. Plant biopharming is recognized for its scalability, speed, versatility, and low production costs and is an increasingly promising molecular pharming vaccine platform for human health. We developed Nicotiana benthamiana-produced SARS-CoV-2 virus-like particle (VLP) vaccine candidates displaying the S-protein of the Beta (B.1.351) variant of concern (VOC), which triggered cross-reactive neutralising antibodies against Delta (B.1.617.2) and Omicron (B.1.1.529) VOCs. In this study, immunogenicity of the VLPs (5µg per dose) adjuvanted with three independent adjuvants i.e. oil-in-water based adjuvants SEPIVAC SWETM (Seppic, France) and "AS IS" (Afrigen, South Africa) as well as a slow-release synthetic oligodeoxynucleotide (ODN) adjuvant designated NADA (Disease Control Africa, South Africa) were evaluated in New Zealand white rabbits and resulted in robust neutralising antibody responses after booster vaccination, ranging from 1:5341 to as high as 1:18204. Serum neutralising antibodies elicited by the Beta variant VLP vaccine also showed cross-neutralisation against the Delta and Omicron variants with neutralising titres ranging from 1:1702 and 1:971, respectively. Collectively, these data provide support for the development of a plant-produced VLP based candidate vaccine against SARS-CoV-2 based on circulating variants of concern.

Abstract P2-19-01: Characterization of fully human internalizing anti-HER2 monoclonal antibodies that compete with Trastuzumab for binding to HER2

Abstract The human epidermal growth factor receptor (HER) family of receptors plays a significant role in the pathogenesis of several human cancers. Among them, HER2 is overexpressed in several cancers. In particular, overexpression with or without gene amplification occurs in 15-30% of breast cancers and this has both prognostic and predictive implications. HER2 overexpression and amplification is associated with shorter disease-free and overall survivals and with resistance to certain hormonal agents as well as increased risk of metastasis to the brain. Two types of treatment targeting HER2 biological activity have been developed: anti-Her2 monoclonal antibodies and small molecule tyrosine kinase inhibitors such as lapatinib and neratinib targeting HER2 and EGFR and Afatinib targeting all HER family members. Trastuzumab is a humanized anti-HER2 monoclonal antibody that binds to domain IV of HER2 extracellular segment and blocks its signaling. It is the first therapeutic antibody targeting Her2 overexpression approved by the FDA. It is administered in combination with standard of care chemotherapy. More recently, since it was shown that Trastuzumab was an internalizing antibody, two antibody drug conjugates using trastuzumab have been approved and used in the standard of care: Ado-Trastuzumab-Emtansine (Kadcyla) consisting of trastuzumab conjugated to the drug mertansine DM1 and fam-trastuzumab-deruxtecan-nhki (Enhertu). Enhertu is another antibody drug conjugate using Trastuzumab to deliver a topoisomerase inhibitor deruxtecan. Our laboratory has been focused in developing fully human internalizing anti-Her2 antibodies that compete or not with trastuzumab for binding to Her2. These antibodies have been developed by immunizing fully human mice with recombinant Her2 protein. Human Ab producing Tc mice (TC-mAb mice) stably maintain a mouse-derived engineered chromosome containing the entire human Ig heavy and kappa chain loci in a mouse Ig knockout background. After production of hybridoma secreting fully human immunoglobulins, the screening process included inhibition of binding of trastuzumab to Her2 by enzyme linked immunoassay and by Octet epitope binning as well as internalization assay. Several internalizing antibodies with Kd ranging from 10-9 M to 10-12 M were selected. They were stratified by their ability to compete or not with trastuzumab. They were further characterized for their ability to deliver a cytotoxic payload in Her2 overexpressing cells as well as for their efficacy to inhibit proliferation, signaling and migration of Her2 overexpressing breast cancer cells. Data related to these antibodies will be presented here. In conclusion, the use of fully human TC mice in our laboratory represents an attractive approach to develop fully human monoclonal antibodies to high value cancer targets that can by-pass the need for humanization and affinity maturation of antibodies. Citation Format: Ginette Serrero, Jianping Dong, Binbin Yue, Udaya Yerramalla, Jun Hayashi. Characterization of fully human internalizing anti-HER2 monoclonal antibodies that compete with Trastuzumab for binding to HER2 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-19-01.

The role of claudin 18.2 and HER-2 in pancreatic cancer outcomes.

To examine the prognostic value of claudin 18.2 (CLDN18.2) and human epidermal growth factor receptor-2 (HER-2) expression in patients with resected pancreatic ductal adenocarcinoma (PDAC). This study enrolled patients who underwent surgery and were diagnosed with PDAC at Suleyman Demirel University Hospital, Turkey between 2015 and 2019. Sixty-eight patients with resected PDAC treated at a medical oncology clinic were assessed. All patients were over the age of 18 years, underwent follow-up and treatment in our unit, and had pathology slides that we could access. Clinicopathological data were obtained from medical files, including the patients' age, sex, pathological parameters, and clinical stage according to the Eighth International Union against Cancer/American Joint Committee on Cancer. Patient survival and the period from the date of diagnosis to death were assessed in the follow-up data. There was no statistically significant difference between CLDN18.2 and HER-2 expression scores for samples and patient clinicopathological characteristics. No HER-2 expression scores of ≥2 were found in the samples. Only 25% (n = 17) of the samples had HER-2 expression scores of +1. CLDN18.2 expression was detected in 54.4% (n = 37) of the patient samples. CLDN18.2 expression scores were +1 in 30.8% (n = 21) of the patient samples, +2 in 16.2% (n = 11), and +3 in 7.4% (n = 5). When CLDN18.2 and HER-2 expression were compared, a statistically significant difference and moderate positive correlation were observed. No significant relationship between HER-2 expression and survival was observed in the survival analysis of PDAC patients; however, high CLDN18.2 expression was related to longer overall survival. Our study is the third to research CLDN18.2 expression in PDAC. HER-2 expression is low and CLDN18.2 expression is high in patients with PDAC. HER-2 expression is not related to overall survival but CLDN18.2 is related and may be used as a prognostic marker in patients with PDAC.

Post-translational modifications optimize the ability of SARS-CoV-2 spike for effective interaction with host cell receptors.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein is the prime target for vaccines, diagnostics, and therapeutic antibodies against the virus. While anchored in the viral envelope, for effective virulence, the spike needs to maintain structural flexibility to recognize the host cell surface receptors and bind to them, a property that can heavily depend upon the dynamics of the unresolved domains, most prominently the stalk. Construction of the complete, membrane-bound spike model and the description of its dynamics are critical steps in understanding the inner working of this key element of the viral infection by SARS-CoV-2. Combining homology modeling, protein-protein docking, and molecular dynamics (MD) simulations, we have developed a full spike structure in a native membrane. Multimicrosecond MD simulations of this model, the longest known single trajectory of the full spike, reveal conformational dynamics employed by the protein to explore the surface of the host cell. In agreement with cryogenic electron microscopy (cryo-EM), three flexible hinges in the stalk allow for global conformational heterogeneity of spike in the fully glycosylated system mediated by glycan-glycan and glycan-lipid interactions. The dynamical range of the spike is considerably reduced in its nonglycosylated form, confining the area explored by the spike on the host cell surface. Furthermore, palmitoylation of the membrane domain amplifies the local curvature that may prime the fusion. We show that the identified hinge regions are highly conserved in SARS coronaviruses, highlighting their functional importance in enhancing viral infection, and thereby, provide points for discovery of alternative therapeutics against the virus.