Monoclonal Antibody Targeting Research Articles

Phase I Study of FT538 + Daratumumab for Treatment of r/r AML

Introduction: Relapsed and refractory (r/r) acute myeloid leukemia (AML) remains an unmet need with immune-therapy based treatments such as hematopoietic stem cell transplantation (HSCT) providing the longest relapse-free survival (RFS). Natural Killer (NK cells) have been shown to effect lysis of AML cells, both in vitro and in vivo across multiple platforms. In particular, “adaptive” NK cells induced in vivo in HSCT recipients after CMV reactivation have been shown to confer an RFS advantage. These cells are characterized phenotypically by the expression of NKG2C, CD57, KIR and downregulation of CD38. CD38 is an ectoenzyme broadly expressed on hematopoietic cells, including approximately 60% of AML. It catalyzes the conversion of nicotinamide-adenine dinucleotide (NAD+) and nicotinamide-adenine dinucleotide phosphate (NADP+) to cyclic adenosine diphosphate (cADP) ribosyl. CD38 knock-out NK cells have increased persistence by having enhanced metabolic fitness and resistance to oxidative stress via a reduction of reactive oxygen species. FT538 is an iPSC-derived NK cell product with a non-cleavable CD16 receptor to augment antibody-dependent cytotoxicity (ADCC), IL-15/IL-15R fusion to increase activation and persistence, and CD38 knockout to enhance its metabolic fitness and avoid fratricide when combined with CD38 monoclonal antibodies. Daratumumab (Dara) is a monoclonal antibody targeting CD38 on the surface of AML cells as well as activated lymphocytes. We hypothesized that the addition of Dara to fludarabine and cyclophosphamide would enhance lymphodepletion and augment ADCC for CD38+ AML leading to better response rates when combined with FT538. Methods: This (NCT04714372) is a phase I, dose-escalation study, utilizing FT538 in combination with fludarabine, cyclophosphamide, and Dara for the treatment of r/r AML. A study schema is presented in Figure 1A. Patients received 5 weekly doses of Dara starting day -12, 2 doses of fludarabine and cyclophosphamide at day -4, and 3 weekly doses of FT538. They were followed for DLT for 28 days after FT538 infusion. Patients with r/r AML after 2 or more lines of therapy and good organ function were enrolled. The primary objective was the safety of this combination, and the endpoints were the incidence of dose-limiting toxicities (DLTs) and incidence of adverse events. Secondary endpoint was the efficacy and predictors of efficacy. Patients evaluable for safety are those who received at least one dose of FT538. Patients evaluable for efficacy are those who completed all doses. Fast-track enrollment was utilized where one patient per dosing level (DL) was enrolled as long as no DLTs were seen with cohort expansion in the event of DLTs or related severe adverse events. Results: Six patients were enrolled on 4 DLs with increasing dose of FT538 from 1x10 8 - 1.5x10 9 cells. Median age was 70 years. Median number of prior lines is 3.5 (3-4). All patients were refractory to most recent therapy. One patient was enrolled on each DL1, DL2, and DL3. Three enrolled on DL4 with 1 completing therapy. Five patients are evaluable for safety and 4 for efficacy. There were no DLTs and we were able to enroll one patient per cohort. Eighty percent (4/5) experienced febrile neutropenia and infections. One patient with a prior biliary stent had choledocholithiasis requiring a complicated intervention. No prolonged cytopenias attributable to FT538 were seen. One patient experienced a G1 CRS lasting 1 day. There were no neurotoxicity events. One patient on DL2 achieved stable disease and one patient on DL4 achieved a CR for an ORR of 50% (2/4). Both went on to receive HSCT and continue to be alive and well without disease with a median follow up of 5 months. This is summarized in Figure 1.B. Macrochimerism (donor cells) was detected for up to 8 days post-infusion. Macrochimerism did not correlate with response but did show that Ki67 expression was present on donor cells suggesting proliferation. Conclusions: FT538 in combination with daratumumab has been tolerated in a highly pre-treated cohort of patients with expected toxicities and a signal of efficacy.

Correlation Revealed between Gemtuzumab-Ozogamicin Efficacy and CD33+ Expression in AML Primary Samples through a Novel AML in Vitro Model

Acute myeloid leukemia (AML) is one of the most difficult blood cancers to treat with increasing incidence in recent years. The disease is characterized by a clonal hematopoietic aggressive disorder of progenitor and stem cells. The prognosis for patients with AML is generally poor. After the first remission, most patients will develop recurrent disease, often within the first year 1. Recent molecular deconvolution of the mechanisms underlying AML disease have impacted the way AML patients are managed in the clinic, going from chemotherapy to the implementation of monoclonal antibodies and antibody-drug conjugates (ADC) 2. One of the limitations to ADC development for AML patients is the lack of AML-specific antigens. CD33 is a recent target which, although being expressed by other normal hematopoietic cells, is also strongly expressed in 80-90% of all AML cells. For these reasons gemtuzumab-ozogamicin (Mylotarg), a monoclonal antibody targeting CD33 covalently linked to the toxin calicheamicin, is the only FDA approved ADC for AML treatment 2. Although these treatments have had an impact on patient care, new therapeutic strategies are required to succeed in effectively treating AML. To date, several AML models have been exploited to predict patients' response 3. The model portfolio comprises in vivo and ex vivo models; however, the difficulties in culturing AML primary cells while maintaining clonal heterogeneity often limit the ability of the assay to recapitulate the disease. The development of a functional experimental model capable of mimicking the heterogeneity and complexity of AML with translational potential is still a major challenge. To overcome the lack of clinically relevant translational models that can stratify sensitive and resistant tumors across different treatments, we developed our proprietary assay, Champions AML VitroScreen ®, to test therapeutic candidates in primary AML samples 4. Our bank of primary, deeply characterized AML samples recapitulates the diversity of multiple AML subtypes from a phenotypic and molecular standpoint. This assay allows for evaluation of cell viability, proliferation, and clonal composition in response to therapeutic intervention using a variety of validated endpoint analyses. To challenge the robustness of the assay, we used the VitroScreen platform to test Mylotarg, in primary AML samples used as models for the different AML subtypes including M1, M2, M3, M4 and M5. To select appropriate AML models, we evaluated the expression of CD33 in AML blasts by high complexity flow cytometry. CD33+ high, intermediate, and low expressing models were included in the study. We measured the IC50 for Mylotarg in more than 20 AML models and correlated the marker expression with drug efficacy. Dose-dependent responses to Mylotarg were observed across multiple models by evaluating cell growth and viability using the CellTiter-Glo ® assay. As additional endpoints cell proliferation, apoptosis, and phenotyping by flow cytometry were included to better interpret Mylotarg mechanism of action. Based on the assay results, primary AML models were classified into different categories, respectively responder, low responder and resistant, based on the IC50 value, and a strong positive correlation between sensitivity to Mylotarg and CD33+ expression was found. The use of deeply characterized AML patient primary samples within the AML VitroScreen ® platform allowed for high throughput drug testing, which represents the ideal clinical translational setting in preclinical research. The use of this innovative system for patient selection and drug screening will support the development of new and tailored therapeutic strategies for patients with primary or recurrent AML, leading to improved patient outcomes.

Real-World Analysis of Treatment Patterns and the Effectiveness and Safety Profile of Daratumumab-Based Regimens in Chinese Patients with Newly Diagnosed or Relapsed/Refractory Multiple Myeloma

Introduction: Daratumumab (DARA) is a human IgGκ monoclonal antibody targeting CD38 with a direct on-tumor and immunomodulatory mechanism of action. Several clinical trials have established DARA-based treatment as a standard of care globally for patients with newly diagnosed or relapsed/refractory multiple myeloma (MM). However, clinical trials do not always reflect routine clinical practice, and real-world (RW) studies thus provide an important complement to conventional clinical trials. Herein, we report results from an observational study that described RW treatment patterns and outcomes in routine clinical practice among patients with MM who were treated with DARA in China. This is possibly the first study to enroll a large population of Chinese patients with MM who were treated with DARA in the RW setting. Methods: This ongoing, multicenter, noninterventional, observational registry study is enrolling Chinese patients who have been diagnosed with symptomatic newly diagnosed or relapsed/refractory MM and either (1) started DARA treatment after August 1, 2019, and were expected to continue ongoing DARA at the time of study initiation (November 3, 2021) or (2) started DARA treatment after study initiation. Patients were excluded from the study if they had received ≥4 prior lines of MM therapy before starting DARA-based treatment or had a diagnosis of other cancers prior to their MM diagnosis. The decision to treat with DARA must have been made prior to and independently of the patient's inclusion in the study, and treatment was administered in accordance with local clinical practice. For patients who started DARA after August 1, 2019, but before study initiation, data were collected both retrospectively through medical chart review and prospectively after enrollment. RW baseline disease characteristics, treatment patterns, response rates, measurable residual disease (MRD), and safety are presented. Outcome and safety analyses were based on the DARA treatment period. Results: As of the cutoff date (April 30, 2023) for this analysis, 210 patients who received ≥1 dose of DARA have been enrolled in the study from 13 participating sites in China. At baseline (last status prior to the first DARA dose), patients had a median age of 64 y (range, 29-89) and a median time since MM diagnosis of 1 y (range, 0-12); the majority of patients had an ECOG performance status of 0 or 1 (82.4%) and a Durie-Salmon MM stage of III (74.4%). Most (83.8%) patients had received ≥1 prior line of therapy before initiating DARA, including 82.4% who had received prior protease inhibitors (PIs) and 58.1% who had received prior immunomodulatory drugs (IMiDs). A summary of prior therapies is provided in Table 1. DARA-based therapy included DARA monotherapy (n = 22) or combination with dexamethasone only (n = 21), PIs ± dexamethasone (n = 57), IMiDs ± dexamethasone (n = 71), PIs and IMiDs ± dexamethasone (n = 29), and other combinations (n = 10). The median DARA exposure time was 5.39 mo (interquartile range [IQR], 2.56-9.69), and the median follow-up time was 10.48 mo (IQR, 7.23-15.31). Of the 179 patients evaluable for response, a best overall response of partial response (PR) or better was achieved by 130 (72.6%) patients and a best response of very good partial response (VGPR) or better was achieved by 93 (52.0%) patients, with responses observed across DARA treatment regimens ( Table 2). MRD results were available for 53/179 (29.6%) patients, with 31/53 (58.5%) patients achieving MRD negativity. Adverse drug reactions were reported for 40 (19.0%) patients overall; events reported in ≥5% of patients included leukopenia (6.2%), thrombocytopenia (5.7%), and neutropenia (5.2%). Serious treatment-emergent adverse events were reported for 29 (13.8%) patients, with pneumonia (n = 10, 4.8%) the only serious event reported in ≥5 patients. Twenty-five patients died as of the cut-off date, regardless of timing (with/without DARA treatment period). Conclusions: This noninterventional, observational study provides RW insights into physician treatment decisions for patients with MM in China and the characteristics of patients who are selected for DARA-based treatment. In addition, the RW effectiveness, duration of therapy, and safety results support the use of DARA-based treatment as a standard of care in Chinese patients with newly diagnosed or relapsed/refractory MM. This study is ongoing, with a total planned enrollment of ~220 patients.

Mogamulizumab for Refractory CD3-CD4+ Lymphocytic-Variant Hypereosinophilic Syndrome

OCS Introduction. Lymphocytic hypereosinophilic syndrome (L-HES) is an indolent T-cell lymphoproliferative disorder characterized by chronic blood hypereosinophilia and eosinophil-related organ damage secondary to the production of eosinophilopoietic cytokines (including interleukin-5) by clonal T cells, among which CD3-CD4+ T cells are the most frequent subset. Both high exposure to oral corticosteroids (OCS), failure and/or toxicity of OCS-sparing therapies and the risk of progression to AITL (up to 5 - 10% of patients) underscore the unmet need for novel treatments targeting the clonal T-cells (and not only eosinophils). We previously reported that peripheral CD3-CD4+ T cells express C-C chemokine receptor 4 (CCR4). We hypothesized that mogamulizumab, an afucosylated monoclonal antibody targeting CCR4-positive cells through antibody-dependent cellular cytotoxicity, could be beneficial for refractory L-HES patients. Methods. We assessed both the expression of CCR4 by clonal CD3-CD4+ T cells in the skin and lymph nodes as well as theability of mogamulizumab to induce ADCC in vitro on sorted CD3-CD4+ T cells from two L-HES patients, using homologous sorted NK cells as effector cells. We then set up a compassionate use program of intravenous mogamulizumab (1.0 mg/kg weekly for the first 28-day cycle, then on days 1 and 15 from subsequent cycles) for refractory L-HES patients despite treatment with immunosuppressants and/or biologics targeting the IL-5 pathway. Complete blood response was defined as complete if the subset of CD3-CD4+ T cells was <0.5% of all lymphocytes, or as partial if the number of CD3-CD4+ T cells decreased by >50% without reaching complete response at the time of the last perfusion. Results. Significant CCR4 expression on tissue CD4+ T cells was evidenced, and NK cells indeed led to the lysis of CD3-CD4+ T-cells coated with mogamulizumab (10 μg/ml). Four patients with refractory L-HES (despite treatment with high-dose OCS, n=4; pegylated interferon alpha 2a; n=3; or mepolizumab, a single patient) and active disease entered the compassionate use program (Table 1). Despite substantial tapering in OCS doses, all cases showed clinical response. Blood responses (either partial or complete, two patients each) and sharp decrease in absolute eosinophil counts (AEC) were reported in all patients ( Figure 1). Both patients with lymph node enlargement rapidly improved. Although prolonged blood and clinical responses have been observed after discontinuation of mogamulizumab, relapses still occurred preceded by an increase in T-cell clone size and absolute eosinophil count (AEC). Rechallenging a relapse with a short course of mogamulizumab resulted in a complete remission for a further 12 months in case #1. In terms of safety, mogamulizumab was discontinued in two patients due to adverse events: one for recurrent infusion-related reactions and one for infectious events. Lymphopenia was reported in 3/4 cases but was preexisting in the 3 cases. Case #4 reported a serious adverse event related to a tumor lysis syndrome leading to the massive release of IL-5 and subsequent rebound of AEC. Hence lower doses of mogamulizumab, transient use of OCS and/or mepolizumab should be considered in patients with very high number of CD3-CD4+ T cells who are about to start mogamulizumab. Discussion. Mogamulizumab represents a new therapeutic option for L-HES patients with severe refractory HES, T-cell clone related symptoms and/or large or rapidly increasing clonal T-cell counts. In patients who achieve complete remission under mogamulizumab, whether fixed repeated (e.g., every 6 months) infusions could be beneficial to prevent relapses and transformation into high-grade lymphoma remains to be investigated. Figure legend. Hematological responses to mogamulizumab in four refractory lymphocytic HES patients. oral corticosteroids; pINF-α: pegylated interferon alpha; MEPO: mepolizumab; MOGA: mogamulizumab.

88TiP A phase Ib study of HMBD-001, a monoclonal antibody targeting HER3, with or without chemotherapy in patients with genetic aberrations in HER3 signaling

88TiP A phase Ib study of HMBD-001, a monoclonal antibody targeting HER3, with or without chemotherapy in patients with genetic aberrations in HER3 signaling

Antibody and immunotherapy in diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma and a heterogeneous B-cell disease. The majority of patients with newly diagnosed disease are cured with first-line combination immunochemotherapy treatment however, those who experience treatment failure have dismal outcomes. Antibody therapies and immunotherapy have provided the single most major advance in the treatment of DLBCL in the last 4 decades. Rituximab, the first immunotherapy, and a monoclonal antibody targeting CD20, improved DLBCL overall survival when added to chemotherapy 2 decades ago. Since then, the advent of further "naked" monoclonal antibodies that target malignant B-cells or stimulate the immune system to kill cancer, as well as antibody-drug conjugates and bispecific antibodies have all entered the DLBCL armamentarium; with 5 antibody therapy approvals in the last 6 years alone. Here we review the literature on antibodies and immunotherapies for DLBCL and the future directions involving this successful group of drugs.

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.

Construction and preclinical evaluation of a zirconium-89 labelled monoclonal antibody targeting PD-L2 in lung cancer

ObjectivesThe aim of this study was to design a novel tracer targeting programmed cell death-ligand 2 (PD-L2) to dynamically monitor PD-L2 expression and perform preclinical screening to identify patients who may benefit from immune checkpoint inhibitor therapy (ICI) therapy. Methods89Zr labelling of DFO-conjugated PD-L2 antibody (ATL2) was carried out in Na2CO3 buffer at pH 7 (37 °C, 1 h). In vitro stability was analysed using radio-thin layer chromatography (radio-TLC). The affinity of [89Zr]Zr-DFO-ATL2 was evaluated by radio-ELISA. Cell uptake, pharmacokinetic, and biodistribution experiments were used to evaluate the biological properties. Micro-PET/CT imaging with [89Zr]Zr-DFO-ATL2 was conducted at different time points. Immunohistochemical and HE staining studies were carried out using tumour tissues from tumour-bearing mice. ResultsThe radiochemical yield of [89Zr]Zr-DFO-ATL2 was 65.6 ± 3.9%, and the radiochemical purity (RCP) of the tracer was greater than 99%. The tracer maintained relatively high stability and had a high affinity for the PD-L2 protein (Kd = 31.85 nM, R2 = 0.94). The uptake of [89Zr]Zr-DFO-ATL2 in A549-PD-L2 cells was higher than that in A549 cells at each time point. Micro-PET/CT showed significant uptake in the tumour region of mice bearing tumours derived from A549-PD-L2 (SUVmax = 3.53 ± 0.09 at 96 h) and H2228 (SUVmax = 2.30 ± 0.12 at 48 h) cells. ConclusionThe high tumour uptake at early imaging time points demonstrates the feasibility of applying [89Zr]Zr-DFO-ATL2 to image PD-L2 expression in tumours and is encouraging for further clinical application in the screening of patients who may benefit from ICI therapy.

Impact of Targeting Moiety Type and Protein Corona Formation on the Uptake of Fn14-Targeted Nanoparticles by Cancer Cells.

The TWEAK receptor, Fn14, is a promising candidate for active targeting of cancer nanotherapeutics to many solid tumor types, including metastatic breast and primary brain cancers. Targeting of therapeutic nanoparticles (NPs) has been accomplished using a range of targeting moieties including monoclonal antibodies and related fragments, peptides, and small molecules. Here, we investigated a full-length Fn14-specific monoclonal antibody, ITEM4, or an ITEM4-Fab fragment as a targeting moiety to guide the development of a clinical formulation. We formulated NPs with varying densities of the targeting moieties while maintaining the decreased nonspecific adhesivity with receptor targeting (DART) characteristics. To model the conditions that NPs experience following intravenous infusion, we investigated the impact of serum exposure in relation to the targeting moiety type and surface density. To further evaluate performance at the cancer cell level, we performed experiments to assess differences in cellular uptake and trafficking in several cancer cell lines using confocal microscopy, imaging flow cytometry, and total internal reflection fluorescence microscopy. We observed that Fn14-targeted NPs exhibit enhanced cellular uptake in Fn14-high compared to Fn14-low cancer cells and that in both cell lines uptake levels were greater than observed with control, nontargeted NPs. We found that serum exposure increased Fn14-targeted NP specificity while simultaneously reducing the total NP uptake. Importantly, serum exposure caused a larger reduction in cancer cell uptake over time when the targeting moiety was an antibody fragment (Fab region of the monoclonal antibody) compared with the full-length monoclonal antibody targeting moiety. Lastly, we uncovered that full monoclonal antibody-targeted NPs enter cancer cells via clathrin-mediated endocytosis and traffic through the endolysosomal pathway. Taken together, these results support a pathway for developing a clinical formulation using a full-length Fn14 monoclonal antibody as the targeting moiety for a DART cancer nanotherapeutic agent.

Efficacy and safety of zolbetuximab for first-line treatment of advanced Claudin 18. 2-positive gastric or gastro-esophageal junction adenocarcinoma: a systematic review and meta-analysis of randomized controlled trials.

Zolbetuximab is a "first-in-class" chimeric lgG1 monoclonal antibody targeting Claudin18.2 (CLDN 18.2). In recent years, several important trials have been published showing that zolbetuximab is associated with improved prognosis in patients with advanced gastric or gastro-esophageal junction (G/GEJ) adenocarcinoma. This promises great change to the current treatment landscape. Therefore, we conducted a systematic review and meta-analysis to evaluate the efficacy and safety of zolbetuximab for first-line treatment of advanced CLDN 18. 2-positive G/GEJ adenocarcinoma. The following databases were searched for relevant studies: PubMed, EMBASE, and Cochrane library (updated 10 June 2023). All randomized trials comparing zolbetuximab plus chemotherapy versus first-line chemotherapy alone for first-line treatment of advanced CLDN 18. 2-positive G/GEJ adenocarcinoma were eligible for inclusion. Data were analyzed using Review Manager 5.4.1 (Cochrane collaboration software). Primary outcomes and measures included overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events (AEs). This systematic review and meta-analysis included three randomized controlled studies involving 1,402 patients (699 receiving zolbetuximab plus chemotherapy and 703 receiving chemotherapy alone). Compared with chemotherapy alone, zolbetuximab plus chemotherapy significantly improved OS (HR = 0.73; 95% CI: 0.68-0.84) and PFS (HR = 0.64; 95% CI: 0.50-0.82), but did not result in a higher ORR (RR = 0.92; 95% CI: 0.82-1.03). Further analysis of CLDN 18.2 expression showed a more significant benefit for OS (HR = 0.69; 95% CI: 0.55-0.87; p = 0.002) and PFS (HR = 0.61; 95% CI: 0.44-0.84; p = 0.003) from zolbetuximab in patients with high expression, while there was significant benefit in patients with lower expression. In terms of AEs, zolbetuximab plus chemotherapy was associated with higher risk of grade 3 and higher AEs, but increased risk of nausea and vomiting were more common. This systematic review and meta-analysis revealed that the effect of zolbetuximab plus chemotherapy was superior to that of chemotherapy alone for first-line treatment of advanced CLDN 18.2-positive G/GEJ adenocarcinoma. Thus, zolbetuximab plus chemotherapy represents a new first-line treatment for these patients. Zolbetuximab plus chemotherapy was associated with higher risk of grade 3 and higher AEs, but was generally manageable. https://www.crd.york.ac.uk/prospero, identifier (CRD42023437126).

A monoclonal antibody targeting spore wall protein 1 inhibits the proliferation of Nosema bombycis in Bombyx mori.

Microsporidia are obligate intracellular single-cell eukaryotic parasites that can infect almost all kinds of animals and cause microsporidiosis. However, there are a few achievements of microsporidiosis treatments. Nosema bombycis could cause a microsporidiosis condition, pébrine, in the silkworm. Treatment and prevention of pébrine are still the research hotspots in sericulture. In this study, N. bombycis was treated with K2CO3, the spore walls were removed by centrifugation, and then, the alkali-soluble germination proteins were used as antigens to develop monoclonal antibodies (mAbs). Three mAbs were successfully screened and one mAb named G9 showed the highest titer among these monoclonal antibodies after enzyme-linked-immunosorbent serologic assay (ELISA). Mass spectrometry analysis confirmed that the mAb G9 could recognize the N. bombycis spore wall protein 1. Furthermore, the heavy chain and light chain sequences of the G9 monoclonal antibody were cloned, respectively. The vectors that expressing the intact antibodies and the single-chain variable fragments (scFvs) of G9 were constructed, and then, these vectors were used to develop the transgenic silkworm cell lines or transgenic silkworms. The inhibitory effects against N. bombycis were evaluated by the count of microsporidia and qPCR. The scFvs showed better effect on blocking the proliferation of N. bombycis than the intact antibody, and the scFv without the secretory signal peptide was more effective than that with signal peptide. Our study has provided novel strategies for microsporidiosis control and the essential groundwork for the future development of N. bombycis-resistant transgenic silkworms.IMPORTANCEThere are a few reports on the resistance of microsporidia, including Nosema bombycis. Here, the alkali-soluble germination proteins of N. bombycis were used as immunogens to prepare a monoclonal antibody, and its single-chain variable fragments effectively blocked microsporidia infection. Our study has provided novel strategies for microsporidiosis control and demonstrated a useful method for the potential treatment of other microsporidia diseases.

Accurate location of two conserved linear epitopes of PEDV utilizing monoclonal antibodies induced by S1 protein nanoparticles

Porcine Epidemic diarrhea virus (PEDV), which can result in severe vomiting, diarrhea, dehydration and death in newborn piglets, poses a great threat to the pig industry around the world. The S1 subunit of S protein is crucial for triggering neutralizing antibodies binding to the receptor. Based on the advantages of high immunogenicity and precise assembly of nanoparticles, the mi3 nanoparticles and truncated S1 protein were assembled by the SpyTag/SpyCatcher system and then expressed in HEK293F cells, whereafter high-efficiency monoclonal antibodies (mAbs) were produced and identified. The obtained five mAbs can bind to various genotypes of PEDV, including a mAb (12G) which can neutralize G1 and G2 genotypes of PEDV in vitro. By further identification of monoclonal antibody target sequences, 507FNDHSF512 and 553LFYNVTNSYG562 were first identified as B-cell linear epitopes, in which 553LFYNVTNSYG562 was a neutralizing epitope. Alanine scans identified the key amino acid sites of two epitopes. Moreover, the results of multiple sequence alignment analysis showed that these two epitopes were highly conserved in various subtype variants. In brief, these findings can serve as a basis for additional research of PEDV and prospective resources for the creation of later detection and diagnostic techniques.

1079TiP A phase I first-in-human study of PRTH-101, an IgG1 monoclonal antibody targeting DDR1, as a monotherapy and combined with pembrolizumab in patients with advanced solid malignancies

1079TiP A phase I first-in-human study of PRTH-101, an IgG1 monoclonal antibody targeting DDR1, as a monotherapy and combined with pembrolizumab in patients with advanced solid malignancies

688P Pharmacokinetics of HMBD-001, a human monoclonal antibody targeting HER3, a CRUK first-in-human phase I trial in patients with advanced solid tumours

688P Pharmacokinetics of HMBD-001, a human monoclonal antibody targeting HER3, a CRUK first-in-human phase I trial in patients with advanced solid tumours

MAb Targeting a Link Between ExoN and MTase of TGEV NSP14.

Porcine transmissible gastroenteritis virus (TGEV) infection results in severe gastrointestinal disease manifesting vomiting, diarrhea in neonatal porcine, with extremely high mortality. Monoclonal antibody (MAb) specific to TGEV nonstructural protein (NSP)14 that contains two functional domains, exonuclease (ExoN) and methyltransferase (MTase) domains, may help elucidate the role of NSP14 in the viral life-cycle. In this study, we developed a murine MAb, designated 12F1, against TGEV NSP14 using traditional cell-fusion technique. It was shown the MAb can exclusively bind to viral NSP14, as evidenced by the results of indirect fluorescent assay and western blotting. Intriguingly, epitope screening assay shown that 12F1 targets a hinge region connecting ExoN and N7-MTase of NSP14.

B-304 Performance of Alternative Proficiency Testing Program for Bayesian Forecasting Tool of Infliximab Exposure in Clinical Pharmacokinetic Laboratory

Abstract Background We have developed a Bayesian (PK) forecasting and dosing tool for Infliximab (IFX), a monoclonal antibody targeting Tumor necrosis factor α. This novel dosing tool employs machine learning and proficiency of the algorithm must be established. Our objective was to implement an alternative proficiency testing program (APT) in the routine clinical (PK) laboratory. Methods The test (PredictrPK® IFX) is validated and measures serum IFX and antibodies to IFX (ATI) concentrations using a homogenous mobility shift assay by size exclusion HPLC and albumin (ALB) by nephelometry. Determinations are inputted with weight, dose, and interdose interval provided on test requisition in the Bayesian forecasting PK tool which uses non-linear mixed effect to calculate the individual parameter estimates, Clearance and predicted trough concentrations. APT is conducted using five previously tested patient samples, blinded to testing personnel and retested in the same manner as the routine method of analysis every six months. APT consists of two components, a component evaluating standalone IFX, ATI, and ALB analytes, and a second component evaluating the Bayesian forecasting PK tool in estimating Clearance and trough concentrations. Criteria for acceptable performance is set at target value ± 20% for standalone analytes and forecasted PK estimates. Acceptable ATP score corresponds to 4/5 samples with passing grade. Results The results from two consecutive APT results with six months intervals is presented in Fig. 1. Comparing the results to the original assayed data at the time of collection, the APT results showed IFX concentration, ATI and ALB within 20% of target value. Clearance and estimated trough concentrations calculated using the Bayesian forecasting tool also met acceptability criteria (100% passing grade). Conclusion We have implemented an APT for Bayesian forecasting tool in the clinical PK laboratory.

Expert consensus on the clinical application of antibody drug conjugates in the treatment of malignant tumors (2023 edition)

Antibody-drug conjugates (ADCs) are a class of targeted biological agents that link cytotoxic drugs to monoclonal antibodies through linkers. The monoclonal antibody targets tumor cells and transports small-molecule cytotoxic drugs for specific delivery and minimal off-target side effects. September 30, 2022, 14 anti-tumor ADC drugs have been approved for marketing in the world, and four ADCs have been approved in China. With the improvement of the clinical accessibility of ADC drugs, clinicians urgently need to understand the molecular characteristics and mechanisms of ADCs, and clarify the indications for rational use of drugs. Patients' survival mainly depends on the appropriate dose and course of treatment and also on proper management of adverse reactions. In view of this, on the basis of the "Expert Consensus on the Clinical Application of Antibody-drug Conjugates for the Treatment of Malignant Tumors (2020 edition)" , Professional Committee on Clinical Research of Oncology Drugs, Chinese Anti-Cancer Association fully combines the existing clinical research evidence and the feasibility of current ADC drugs in China to update the consensus content. This consensus aims to provide a systematic overview of ADC drugs, so as to provide practical and effective suggestions and references for clinicians to apply and manage ADC drugs more accurately.

Natalizumab Treatment Induces Proinflammatory CD4 T Cells Preferentially in the Integrin β7+ Compartment.

Natalizumab, a monoclonal humanized antibody targeting integrin α4, inhibits the transmigration of lymphocytes into the CNS by preventing the interaction of integrin α4β1 with V-CAM expressed on brain vascular endothelial cells. Although natalizumab treatment reduces the clinical relapse rate in patients with relapsing-remitting MS, its discontinuation after reactivation of the JC virus is associated with a rebound of the disease in 20% of patients. The mechanisms of this rebound are not elucidated, but natalizumab increases the frequencies of circulating CD4 T cells expressing proinflammatory cytokines as well as the proportion of circulating Th17/Th1 cells (Th1-like Th17 cells). Gut-derived memory CD4 T cells are a population of growing interest in the pathogenesis of MS, but whether and how their properties are affected by natalizumab is not known. Here, we studied the phenotype and cytokine expression profile of circulating gut-derived memory CD4 T cells in patients with relapsing-remitting MS under natalizumab. We identified gut-derived memory CD4 T cells by their expression of integrin β7 and compared their properties and those of integrin β7- memory CD4 T cells across healthy donors and patients with relapsing-remitting MS treated or not with natalizumab. We also compared the capacity of integrin β7- and integrin β7+ CD4 T-cell subsets to transmigrate in vitro across a model of blood-brain barrier. The proportions of proinflammatory Th17/Th1 cells as well as of IL-17A+IFNγ+ and IL-17A+GM-CSF+ cells were higher in memory CD4 T cells expressing integrin β7 in patients receiving natalizumab compared with healthy donors and patients with relapsing-remitting MS not receiving natalizumab. By contrast, integrin β7 negative memory CD4 T cells only presented a modest increased in their proportion of Th17/Th1 cells under natalizumab. We further observed that integrin β7+ Th17/Th1 cells migrated as efficiently as integrin β7- Th17/Th1 across a monolayer of brain microvascular endothelial cells. Our study shows that circulating integrin β7+ memory CD4 T cells of patients with relapsing-remitting MS under natalizumab are enriched in proinflammatory cells supporting the hypothesis that integrin β7+ memory CD4 T cells could play a pathogenic role in the disease rebound observed at natalizumab discontinuation.

Efficacy and Safety of Anti-calcitonin Gene-Related Peptide (CGRP) Monoclonal Antibodies in Preventing Migraines: A Systematic Review.

The neuropeptide calcitonin gene-related peptide (CGRP) is an essential pathophysiological treatment for migraines. A unique class of medications called CGRP monoclonal antibodies target CGRP and its receptor and have demonstrated promising benefits in the treatment and prevention of migraines. This study sought to identify and assess the quality of existing systematic reviews about the effectiveness of CGRP antibodies for preventing migraines, as well as systematically review and synthesize the evidence on these topics. This included the four Food and Drug Administration (FDA)-approved medications erenumab, galcanezumab, fremanezumab, and eptinezumab. The effectiveness and safety of these monoclonal antibodies in preventing migraines should also be examined in light of patient characteristics, and any gaps in the body of knowledge should be noted in order to suggest new lines of investigation. Data gathering included a thorough search of internet databases (PubMed, Cochrane Library, Web of Science, and Scopus) for relevant research released between 2018 and 2023. The findings imply that CGRP monoclonal antibodies are efficient and secure for preventing migraines and may be considered a first-line alternative for treating migraines and drug misuse. The results further imply that combination treatment with CGRP antibodies and onabotulinumtoxinA may enhance the prevention of migraine in adults. With suggestions for more studies to find and address these variables, the significance of genetic and epigenetic factors in the progression of pediatric patients' acute postoperative pain to chronic postsurgical pain is underlined. All four anti-CGRP monoclonal antibodies, erenumab, fremanezumab, galcanezumab, and eptinezumab, were shown to be safe and effective for the prevention of migraine when the research additionally looked at their individual effectiveness and safety. Additionally, the study discovered considerable variances in effectiveness amongst various groups. However, further investigation is required to establish the best time and dosage and the effect of patient characteristics on the effectiveness and safety of these medications.

Small-interfering RNA targeting proprotein convertase subtilisin/kexin type 9 might promote fatty liver disease and hepatocellular carcinoma through upregulation of CD36.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) binds to low-density lipoprotein (LDL) receptor and fatty acid translocase CD36, inducing lysosomal degradation of these two receptors in the liver cells. Both monoclonal antibody (mAb) and small-interfering RNA (siRNA) targeting PCSK9 have been designed for treatment of familial hypercholesterolemia recently, with elevating LDL receptors on the liver cell surface and increasing LDL uptake as the main beneficial mechanism. However, given that the binding domains of PCSK9 for LDL receptor and CD36 are different, and PCSK9 mAb only attacks the domain for LDL receptor, CD36 expression remains partially controlled under PCSK9 mAb treatment. In contrast, PCSK9 siRNA brings on complete loss of PCSK9, resulting in overexpression of CD36. Based on the fact that CD36 is a key factor in the pathogenesis of non-alcoholic fatty liver disease (NAFLD) and subsequent hepatocellular carcinoma (HCC), the risk of developing NAFLD and HCC on long-term use of PCSK9 siRNA is thus raised as a hypothesis. Additionally, because CD36 is also involved in the promotion of malignant diseases other than HCC, such as acute myeloid leukemia, gastric cancer, breast cancer, and colorectal cancer, the speculative danger of flourishing these malignancies by PCSK9 siRNA is discussed as well.