High-affinity Monoclonal Antibody Research Articles

Preclinical Efficacy of VTX-0811: A Humanized First-in-Class PSGL-1 mAb Targeting TAMs to Suppress Tumor Growth

Omnipresent suppressive myeloid populations in the tumor microenvironment limit the efficacy of T-cell-directed immunotherapies, become more inhibitory after administration of T-cell checkpoint inhibitors, and are overall associated with worse survival of cancer patients. In early clinical trials, positive outcomes have been demonstrated for therapies aimed at repolarizing suppressive myeloid populations in the tumor microenvironment. We have previously described the key role of P-selectin glycoprotein ligand-1 (PSGL-1) in maintaining an inhibitory state of tumor-associated macrophages (TAMs), most of which express high levels of PSGL-1. Here we describe a novel, first-in-class humanized high-affinity monoclonal antibody VTX-0811 that repolarizes human macrophages from an M2-suppressive phenotype towards an M1 inflammatory phenotype, similar to siRNA-mediated knockdown of PSGL-1. VTX-0811 binds to PSGL-1 of human and cynomolgus macaque origins without inhibiting PSGL-1 interaction with P- and L-Selectins or VISTA. In multi-cellular assays and in patient-derived human tumor cultures, VTX-0811 leads to the induction of pro-inflammatory mediators. RNAseq data from VTX-0811 treated ex vivo tumor cultures and M2c macrophages show similar pathways being modulated, indicating that the mechanism of action translates from isolated macrophages to tumors. A chimeric version of VTX-0811, consisting of the parental murine antibody in a human IgG4 backbone, inhibits tumor growth in a humanized mouse model of cancer. VTX-0811 is exceptionally well tolerated in NHP toxicology assessment and is heading into clinical evaluation after successful IND clearance.

Establishment and application of PDCoV antigen-specific DAS-ELISA detection method

BackgroundPorcine deltacoronavirus (PDCoV) is a swine enteropathogenic coronavirus that affects young pigs, causing vomiting, acute diarrhea, dehydration, and even death. There is growing evidence that PDCoV can undergo cross-species as well as zoonotic transmissions. Due to the frequent outbreaks of this deadly virus, early detection is essential for effective prevention and control. Therefore, developing a more convenient and reliable method for PDCoV detection is the need of the hour.ResultsThis study utilized a high-affinity monoclonal antibody as the capture antibody and a horseradish peroxidase labeled polyclonal antibody as the detection antibody to develop an enzyme-linked immunosorbent assay (DAS-ELSA) for PDCoV detection.Both antibodies target the PDCoV nucleocapsid (N) protein. The findings of this study revealed that DAS-ELISA was highly specific to PDCoV and did not cross-react with other viruses to cause swine diarrhea. The limit of detection of the virus titer using this method was 103 TCID50/mL of PDCoV particles. The results of a parallel analysis of 239 known pig samples revealed a coincidence rate of 97.07% (κ = 0.922) using DAS-ELISA and reverse transcriptase PCR (RT-PCR). The DAS-ELISA was used to measure the one-step growth curve of PDCoV in LLC-PK cells and the tissue distribution of PDCoV in infected piglets. The study found that the DAS-ELISA was comparable in accuracy to the TCID50 method while measuring the one-step growth curve. Furthermore, the tissue distribution measured by DAS-ELISA was also consistent with the qRT-PCR method.ConclusionThe developed DAS-ELISA method can be conveniently used for the early clinical detection of PDCoV infection in pigs, and it may also serve as an alternative method for laboratory testing of PDCoV.

A targetable secreted neural protein drives pancreatic cancer metastatic colonization and HIF1a nuclear retention.

Pancreatic ductal adenocarcinoma (PDAC) is an increasingly diagnosed cancer that kills 90% of afflicted patients, with most patients receiving palliative chemotherapy. We identified neuronal pentraxin 1 (NPTX1) as a cancer secreted protein that becomes over-expressed in human and murine PDAC cells during metastatic progression and identified adhesion molecule with Ig like domain 2 (AMIGO2) as its receptor. Molecular, genetic, biochemical and pharmacologic experiments revealed that secreted NPTX1 acts cell-autonomously on the AMIGO2 receptor to drive PDAC metastatic colonization of the liver-the primary site of PDAC metastasis. NPTX1-AMIGO2 signaling enhanced hypoxic growth and was critically required for hypoxia induced factor-1a (HIF1a) nuclear retention and function. NPTX1 is over-expressed in human PDAC tumors and upregulated in liver metastases. Therapeutic targeting of NPTX1 with a high-affinity monoclonal antibody substantially reduced PDAC liver metastatic colonization. We thus identify NPTX1-AMIGO2 as druggable critical upstream regulators of the HIF1a hypoxic response in PDAC.

The Impact of Lebrikizumab on Vaccine-Induced Immune Responses: Results from a Phase3 Study in Adult Patients with Moderate-to-Severe Atopic Dermatitis.

Lebrikizumab, a high-affinity IgG4 monoclonal antibody that selectively inhibits interleukin-13 with high binding affinity and slow dissociation rate, prevents the formation of the interleukin-4Rα/interleukin-13Rα1heterodimer receptor signaling complex. Here we report the impact of lebrikizumab on responses to two non-live vaccines in adult patients with moderate-to-severe atopic dermatitis (AD). ADopt-VA (NCT04626297) was a double-blind, placebo-controlled, parallel-group, 16-week, phase3 randomized study to assess the impact of lebrikizumab treatment on non-live vaccine immune responses, and efficacy and safety of lebrikizumab compared with placebo. Eligible patients included adults from 18 to 55years of age with moderate-to-severe chronic AD who were randomly assigned 1:1 to lebrikizumab 250mg every 2weeks or placebo and stratified according to disease severity. The primary endpoints were the development of a booster response to tetanus toxoid and a positive antibody response to meningococcal conjugate vaccine (MCV), 4weeks after administration of the corresponding vaccine. At week16, 73.6% of patients in the lebrikizumab group (n = 78/106) achieved Tdap booster response compared with 73.4% of patients in the placebo group (n = 58/79). MCV vaccine response was observed in 86.9% of patients in the lebrikizumab group (n = 86/99) and 75.0% of patients in the placebo group (n = 60/80). At week16, IGA0,1 with ≥ 2-point improvement from baseline was achieved by 40.6% (n = 51/125) of patients treated with lebrikizumab and 18.9% (n = 23/122) of patients who received placebo (p < 0.001). There was a higher proportion of patients achieving EASI75 at week16 in the lebrikizumab-treated patients (58.0%, n = 72/125) compared with placebo (32.7%, n = 40/122, p < 0.001). Treatment with lebrikizumab did not impact response to non-live vaccines Tdap and MCV in this study. Lebrikizumab treatment had a significant degree of efficacy compared to placebo across multiple endpoints. ClinicalTrials.gov identifier NCT04626297.

A high affinity monoclonal antibody against HLA-E-VL9 enhances natural killer cell anti-tumor killing.

A high affinity monoclonal antibody against HLA-E-VL9 enhances natural killer cell anti-tumor killing by checkpoint inhibition and antibody dependent cellular cytotoxicity.

High-affinity monoclonal antibodies against the porcine epidemic diarrhea virus S1 protein

The porcine epidemic diarrhea virus (PEDV) infection inflicted substantial economic losses upon the global pig-breeding industry. This pathogen can infect all pigs and poses a particularly high fatality risk for suckling piglets. The S1 subunit of spike protein is a crucial target protein for inducing the particularly neutralizing antibodies that can intercept the virus-host interaction and neutralize virus infectivity. In the present study, the HEK293F eukaryotic expression system was successfully utilized to express and produce recombinant S1 protein. Through quantitative analysis, five monoclonal antibodies (mAbs) specifically targeting the recombinant S1 protein of PEDV were developed and subsequently evaluated using enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay (IFA), and flow cytometry assay (FCA). The results indicate that all five mAbs belong to the IgG1 isotype, and their half-maximal effective concentration (EC50) values measured at 84.77, 7.42, 0.89, 14.64, and 7.86 pM. All these five mAbs can be utilized in ELISA, FCA, and IFA for the detection of PEDV infection. MAb 5-F9 exhibits the highest sensitivity to detect as low as 0.3125 ng/mL of recombinant PEDV-S1 protein in ELISA, while only 0.096 ng/mL of mAb 5-F9 is required to detect PEDV in FCA. The results from antigen epitope analysis indicated that mAb 8-G2 is the sole antibody capable of recognizing linear epitopes. In conclusion, this study has yielded a highly immunogenic S1 protein and five high-affinity mAbs specifically targeting the S1 protein. These findings have significant implications for early detection of PEDV infection and provide a solid foundation for further investigation into studying virus-host interactions.

Efficacy of lebrikizumab in adolescent patients with moderate-to-severe atopic dermatitis: 16-week results from three randomized phase 3 clinical trials

Background Lebrikizumab, a high-affinity monoclonal antibody targeting IL-13, previously demonstrated clinical efficacy in three randomized, double-blind, placebo-controlled Phase 3 trials that included adults and adolescents with moderate-to-severe atopic dermatitis (AD): ADvocate1, ADvocate2, and ADhere. Aim This subset analysis evaluated 16-week physician- and patient-reported outcomes of lebrikizumab in the adolescent patients enrolled in these three trials. Methods Eligible adolescents (≥12 to <18 years weighing ≥40kg) were randomized 2:1 to subcutaneous lebrikizumab (500 mg loading doses at baseline and Week 2 followed by 250 mg every 2 weeks) or placebo as monotherapy in ADvocate1&2, and in combination with topical corticosteroids (TCS) in the ADhere study. Week 16 analyses included clinical efficacy outcomes (IGA (0,1) with ≥2-point improvement, EASI 75, EASI 90), patient-reported Pruritus NRS ≥4-point improvement and Sleep-Loss Scale ≥2-point improvement. Results Pooled ADvocate1&2 16-week results in lebrikizumab (N = 67) vs placebo (N = 35) were: IGA (0,1) 46.6% vs 14.3% (p < 0.01), EASI 75 62.0% vs 17.3% (p < 0.001), EASI 90 40.7% vs 11.5% (p < 0.01), Pruritus NRS 48.9% vs 13.1% (p < 0.01), and Sleep-Loss Scale 26.9% vs 6.9% (p = 0.137). Corresponding results for ADhere, (lebrikizumab + TCS, N = 32; placebo + TCS, N = 14), were consistent. Conclusions Lebrikizumab treatment demonstrated efficacy in improving the signs and symptoms of AD in adolescent patients, consistent with the ADvocate and ADhere overall population results.

Hapten design, monoclonal antibody preparation and immunoassay development for direct detection of the toxic metabolite of nitrovin without derivatization from fish

Nitrovin, classified as a nitrofuran drug, has been banned in numerous countries due to its carcinogenic effect on human health. However, existing analytical techniques for its detection are laborious, requiring an overnight derivatization process lasting 16 h. In this study, novel haptens were designed to prepare antibodies against aminogunidine (AGD), the metabolite of nitrovin, and then developed an indirect competitive enzyme-linked immunosorbent assay (icELISA) method to detect AGD from fish samples without derivatization for the first time. Computer-assisted molecular modeling predicted the efficiency of novel haptens by conformational studies and electronic analysis. The results were consistent with the predicted results in producing high-affinity monoclonal antibody (mAb) against AGD. The half-inhibition concentration (IC50) value of icELISA was 0.80 ng mL−1 for AGD, with a limit of detection of 0.27 μg kg−1 and recoveries of 89.8%–97.2%. The results showed that this new hapten design and synthesis provided a great prospect to obtain high-affinity mAb for AGD. This developed icELISA substantially avoided the conventional and lengthy derivatization process and was an effective method for the direct detection of AGD in fish tissue without derivatization.

Abstract PO4-18-11: Phase 1 study of the tissue factor-targeting antibody-drug conjugate XB002 in patients with advanced solid tumors (JEWEL-101): Design of the triple-negative and hormone receptor-positive breast cancer expansion cohorts

Abstract Background: Tissue factor (TF) is a transmembrane protein that functions as a factor VIIa receptor, initiating the extrinsic coagulation cascade. TF is aberrantly expressed in multiple solid tumors, including breast cancer (BC), and its expression is associated with disease progression and poor prognosis (van den Berg et al. Blood 2012). Microtubule-targeting agents are a cornerstone of treatment for metastatic BC. XB002 is a novel antibody-drug conjugate (ADC) composed of a high-affinity TF-directed human monoclonal antibody conjugated to the zovodotin linker-payload. Zovodotin consists of an auristatin-based payload and a protease-cleavable linker and is designed to lower off-target deconjugation and improve tolerability compared with other microtubule inhibitor linker-payloads. In preclinical studies, XB002 did not interfere with coagulation and demonstrated antitumor activity with an encouraging safety profile. XB002 is being evaluated in JEWEL-101, an ongoing trial in patients (pts) with advanced solid tumors, including BC. Preliminary results from the dose-escalation stage of JEWEL-101 showed XB002 was well tolerated at multiple dose levels with no bleeding events or treatment-related peripheral neuropathy (PN) and low-grade ocular toxicity (Ulahannan et al. ENA 2022). Presented here is the study design of the tumor-specific expansion stage, including triple-negative BC (TNBC) and hormone receptor-positive BC (HR+ BC) cohorts. Trial design and statistical methods: JEWEL-101 (NCT04925284) is a multicenter, open-label, phase 1 trial evaluating the safety, tolerability, pharmacokinetics (PK), and antitumor activity of XB002 in advanced solid tumors. Single-agent XB002 at the recommended dose will be assessed in the BC expansion cohorts utilizing Simon’s Two-Stage design. Eligibility criteria: The trial will enroll adult pts with TNBC (ER-/PR-/HER-2-negative or low) and HR+ BC (ER+ and/or PR+ and HER-2-negative or low) into 2 separate cohorts. HER-2 negativity is defined as either HER-2 negative or low by local ISH or IHC assessment. For both cohorts, pts must have received 1–3 lines of prior systemic anticancer therapies for locally advanced or metastatic disease. Pts in the HR+ BC cohort must have received prior endocrine therapy and CDK4/6 inhibitor. All pts must have cytologically or histologically and radiologically confirmed BC that is inoperable, locally advanced, metastatic, or recurrent. Documented radiographic progression during or following their last systemic anticancer therapy is required. All pts must also have measurable disease per RECIST 1.1 by investigator assessment, archival (&amp;lt; 2 years) or fresh tumor tissue, ECOG PS 0 or 1, and adequate organ and marrow function. Pts with grade 1 PN are allowed. Concomitant anticoagulation therapy while receiving XB002 is permitted if clinically indicated. Key exclusions are prior use of TF-targeting or auristatin derivate-based ADC; uncontrolled, significant intercurrent or recent illness, including acute or chronic significant ocular disorders; major surgery within 4 weeks; and corrected QT interval calculated by the Fridericia formula &amp;gt;480 ms per ECG. Specific aims: The primary objective of the expansion stage is to evaluate the preliminary efficacy of XB002 by estimating the objective response rate per RECIST 1.1 as assessed by the investigator. Secondary objectives include safety and tolerability, PK, immunogenicity, progression-free survival, duration of response, and overall survival. Accrual: Up to 28 pts will be enrolled into each BC cohort. Enrollment is planned across sites in the US, Europe, and Asia-Pacific. Contact information: Exelixis Clinical Trials, druginfo@exelixis.com, 1-888-393-5494 Citation Format: Susanna Ulahannan, Melissa Johnson, Mia Weiss, Andrae Vandross, Sofia Vidal-Cardenas, Mustafa Syed, Anthony Tolcher. Phase 1 study of the tissue factor-targeting antibody-drug conjugate XB002 in patients with advanced solid tumors (JEWEL-101): Design of the triple-negative and hormone receptor-positive breast cancer expansion cohorts [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-18-11.

Abstract PO4-06-11: Development of fully human anti-progranulin monoclonal antibodies as inhibitors of triple negative breast cancer cell growth and tumor formation

Abstract Triple negative breast cancer (TNBC) is characterized by invasiveness and poor survival. Identifying novel TNBC targeted therapies to potentiate standard of care (SOC) therapy, is an unmet need. In the past 4 years, several targeted therapies for TNBC have been approved by the Food and Drug Administration (FDA). However, the identification of targeted therapies against other biological drivers of TNBC remains important. Progranulin (PGRN/GP88) is a biological driver of tumorigenesis, survival, and drug resistance in breast cancer. PGRN/GP88 tissue expression is an independent prognostic factor of recurrence while elevated serum PGRN/GP88 level is associated with poor outcomes such as progression of disease and shortened survival. PGRN/GP88 expression is elevated in 30% TNBC. The importance of inhibiting PGRN/GP88 effect on the proliferation and tumor growth of triple negative breast cancer cells was previously established. In the current study, in association with Precision Antibody, we developed anti-PGRN/GP88 fully human monoclonal antibodies by immunizing TC transgenic humanized mice with recombinant human progranulin. Within 60 days since the start of immunization, several fully human monoclonal antibodies were successfully developed, characterized by several functional assays including neutralization, inhibition of PGRN/GP88 cell surface binding, proliferation, migration in MDA-MB-231 cells in vitro and in vivo. Results: The inhibition of PGRN/GP88 action by fully human monoclonal antibodies inhibited proliferation and migration in a dose-and time-dependent fashion in TNBC cells. Octet analysis determined Kd in the range of 10−11 M to 10−10 M. Transwell assay showed that anti-PGRN treatment inhibited migration In vivo xenograft studies with MDA-MB-231 cells injected in athymic nude mice showed that several fully human anti-PGRN antibodies inhibited tumor growth when compared to antibody control treated mice. In vivo dose response of AG01 in MDAMB-231 tumor bearing mice will be provided. Conclusion: PGRN/GP88 represents a therapeutic target for TNBC with two companion diagnostics (tissue test and ELISA to measure GP88 circulating levels). The use of the TC transgenic mice allows for the rapid development of fully human high affinity monoclonal antibodies bypassing the need for chimerization or humanization of mouse monoclonal antibodies. The development of fully human anti-progranulin antibodies provides novel targeted therapeutic option for TNBC. This work is supported by a an SBIR grant 5R44 CA 224718 from the National Cancer Institute to GS. Citation Format: Ginette Serrero, Jianping Dong, Jun Hayashi, Chun Dong. Development of fully human anti-progranulin monoclonal antibodies as inhibitors of triple negative breast cancer cell growth and tumor formation [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-06-11.

Development and therapeutic evaluation of 5D3(CC-MLN8237)3.2 antibody-theranostic conjugates for PSMA-positive prostate cancer therapy.

Prostate cancer (PC) is an aggressive cancer that can progress rapidly and eventually become castrate-resistant prostate cancer (CRPC). Stage IV metastatic castrate-resistant prostate cancer (mCRPC) is an incurable late-stage cancer type with a low 5-year overall survival rate. Targeted therapeutics such as antibody-drug conjugates (ADCs) based on high-affinity monoclonal antibodies and potent drugs conjugated via smart linkers are being developed for PC management. Conjugating further with in vitro or in vivo imaging agents, ADCs can be used as antibody-theranostic conjugates (ATCs) for diagnostic and image-guided drug delivery. In this study, we have developed a novel ATC for PSMA (+) PC therapy utilizing (a) anti-PSMA 5D3 mAb, (b) Aurora A kinase inhibitor, MLN8237, and (c) for the first time using tetrazine (Tz) and trans-cyclooctene (TCO) click chemistry-based conjugation linker (CC linker) in ADC development. The resulting 5D3(CC-MLN8237)3.2 was labeled with suitable fluorophores for in vitro and in vivo imaging. The products were characterized by SDS-PAGE, MALDI-TOF, and DLS and evaluated in vitro by optical imaging, flow cytometry, and WST-8 assay for cytotoxicity in PSMA (+/-) cells. Therapeutic efficacy was determined in human PC xenograft mouse models following a designed treatment schedule. After the treatment study animals were euthanized, and toxicological studies, complete blood count (CBC), blood clinical chemistry analysis, and H&E staining of vital organs were conducted to determine side effects and systemic toxicities. The IC50 values of 5D3(CC-MLN8237)3.2-AF488 in PSMA (+) PC3-PIP and PMSA (-) PC3-Flu cells are 8.17nM and 161.9nM, respectively. Pure MLN8237 shows 736.9nM and 873.4nM IC50 values for PC3-PIP and PC3-Flu cells, respectively. In vivo study in human xenograft mouse models confirmed high therapeutic efficacy of 5D3(CC-MLN8237)3.2-CF750 with significant control of PSMA (+) tumor growth with minimal systemic toxicity in the treated group compared to PSMA (-) treated and untreated groups. Approximately 70% of PSMA (+) PC3-PIP tumors did not exceed the threshold of the tumor size in the surrogate Kaplan-Meyer analysis. The novel ATC successfully controlled the growth of PSMA (+) tumors in preclinical settings with minimal systemic toxicities. The therapeutic efficacy and favorable safety profile of novel 5D3(CC-MLN8237)3.2 ATC demonstrates their potential use as a theranostic against aggressive PC.

The role of ixekizumab in the treatment of nonradiographic axial spondyloarthritis.

Nonradiographic axial spondyloarthritis (nr-axSpA) is a subtype of SpA with undeveloped definite radiographic sacroiliitis. Tumor necrosis factor inhibitors have demonstrated effectiveness in nr-axSpA patients who do not respond to first-line therapy. More recently, accumulated data from genetic, experimental, and clinical studies revealed that IL-17 is a key player in the pathogenesis of SpA, leading to development of new biologics directly inhibiting IL-17. Among them, ixekizumab is a high-affinity monoclonal antibody that selectively targets IL-17A and has exhibited significant efficacy and acceptable safety profiles in the treatment of nr-axSpA. The aim of this paper is to narratively review the recent insights of IL-17 in the pathogenesis of axSpA and discuss the effectiveness and safety of ixekizumab in treatment of nr-axSpA.

Sustained Improvements in Clinical and Patient-Reported Outcomes and Quality of Life Through 5Years Among Ixekizumab-Treated Patients with Complete Clearance of Scalp Psoriasis by Week 60.

Ixekizumab, a high-affinity monoclonal antibody that selectively targets interleukin-17A, is approved for the treatment of moderate-to-severe plaque psoriasis. Since scalp psoriasis can be burdensome and challenging to treat with non-systemic therapies, this post hoc analysis focused on scalp psoriasis in patients with moderate-to-severe plaque psoriasis and baseline scalp involvement. The analysis considered a holistic concept of clearance through 5years of ixekizumab treatment. Ixekizumab-treated patients with baseline scalp involvement were pooled from three multicenter, randomized, double-blind, placebo-controlled, phase 3 trials (integrated UNCOVER-1/2 and UNCOVER-3). Analyses were performed on a subpopulation of patients who achieved complete resolution of scalp psoriasis at Week 60 (i.e., Week 60 Psoriasis Scalp Severity Index [PSSI-0] responders) and on the overall patient population (i.e., Week 60 PSSI-0 responders and non-responders), which was used as a reference. Clinical outcomes (PSSI), patient-reported outcomes (Itch Numeric Rating Scale [NRS] score, Skin Pain Visual Analogue Scale [VAS]), quality of life (Dermatology Life Quality Index [DLQI]), and concurrent outcomes were assessed from baseline through 5years. Descriptive statistics of observed data were reported. After 60weeks of ixekizumab treatment, 88.4% (UNCOVER-1/2) and 75.9% (UNCOVER-3) of patients with baseline scalp involvement achieved complete clearance (PSSI-0) of scalp psoriasis. Substantial improvements in the clinical outcomes (PSSI), patient-reported outcomes (Itch NRS, Skin Pain VAS), and quality of life (DLQI) were achieved by Week 60 and sustained through Week 264 in the Week 60 PSSI-0 responders and in the overall patient population. Additionally, a significant proportion of Week 60 PSSI-0 responders achieved concurrent complete scalp and skin clearance and quality of life improvement through 5years. Continued treatment with ixekizumab provided long-term sustained scalp clearance over 5years to patients with moderate-to-severe plaque psoriasis and baseline scalp involvement, and holistic improvements occurred across clinical outcomes, patient-reported outcomes, and quality of life. NCT01474512 (UNCOVER-1), NCT01597245 (UNCOVER-2), and NCT01646177 (UNCOVER-3).

A Phase 1, Randomized, Double-Blind, Placebo-Controlled, Single Ascending Dose Study to Evaluate the Pharmacokinetics, Immunogenicity, Safety, and Tolerability After Subcutaneous Administration of Tozorakimab in Healthy Chinese Participants.

Tozorakimab is a high-affinity human immunoglobulin G1 monoclonal antibody that neutralizes interleukin (IL)-33, an IL-1 family cytokine. This phase 1, single-center, randomized, double-blind, placebo-controlled, single ascending dose study (NCT05070312) evaluated tozorakimab in a healthy Chinese population. Outcomes included the characterization of the pharmacokinetic (PK) profile and immunogenicity of tozorakimab. Safety outcomes included treatment-emergent adverse events (TEAEs) and clinical laboratory, electrocardiogram, and vital sign parameters. Healthy, non-smoking, male, and female Chinese participants aged 18-45 years with a body mass index 19-24kg/m2 were enrolled. In total, 36 participants across 2 cohorts of 18 participants were randomized 2:1 to receive a single subcutaneous dose of tozorakimab (300mg [2mL] or 600mg [4mL]) or matching placebo (2 or 4mL). Tozorakimab showed dose-dependent serum PK concentrations with an approximate monophasic distribution in serum over time and a maximum observed peak concentration of 20.1 and 33.7μg/mL in the 300- and 600-mg cohorts, respectively. No treatment-emergent anti-drug antibodies for tozorakimab were observed in any of the participants. There were no clinically relevant trends in the occurrence of TEAEs across the treatment groups. There were no clinically relevant trends over time in clinical laboratory (hematology, clinical chemistry, and urinalysis), electrocardiogram, or vital sign parameters in any treatment group. Overall, tozorakimab demonstrated dose-dependent systemic exposure in healthy Chinese participants and was well tolerated, with no safety concerns identified in this study.

Abstract 1864: New generation of fully human anti-progranulin monoclonal antibodies inhibiting migration and tumor formation of non-small cell carcinoma cells

Abstract Advanced carcinomas of the lung or the breast are characterized by invasiveness and poor survival. Identifying novel targeted therapies to potentiate standard of care (SOC) therapy, remains an unmet need. In the past 4 years, numerous targeted therapies in Oncology have been approved by the Food and Drug Administration (FDA). However, the identification of targeted therapies against direct tumor biological drivers remains important. Progranulin (PGRN/GP88) is a biological driver of tumorigenesis, survival, and drug resistance in multiple cancers including breast and lung cancers. PGRN/GP88 tissue expression is an independent prognostic factor of recurrence and mortality while elevated serum PGRN/GP88 level is associated with poor outcomes such as progression of disease and shortened survival. The importance of inhibiting PGRN/GP88 expression or action effect on the proliferation and tumor growth of several cancers has been established by several laboratories including ours. In the current study, in association with Precision Antibody, we developed anti-PGRN/GP88 fully human monoclonal antibodies by immunizing TC transgenic humanized mice with recombinant human progranulin. Within 60 days following the start of immunization, several fully human anti-progranulin monoclonal antibodies were developed, characterized by several functional assays including neutralization, inhibition of PGRN/GP88 cell surface binding, proliferation, migration in vitro and tumor formation in vivo. Results: The inhibition of PGRN/GP88 action by fully human monoclonal antibodies inhibited cell proliferation and migration in a dose-and time-dependent fashion. Octet analysis determined Kd in the range of 10−11 M to 10−10 M. Transwell assay showed that anti-PGRN treatment inhibited migration of non-small cell lung cancer cells such as H1299 and A549 cells. In vivo xenograft studies with H1299 cells injected in athymic nude mice showed that fully human anti-PGRN antibodies inhibited tumor growth when compared to antibody control treated mice. Conclusion: PGRN/GP88 represents a therapeutic target for non-small cell carcinoma with two companion diagnostics (tissue test and ELISA to measure GP88 circulating levels). The use of the TC transgenic mice allows for the rapid development of fully human high affinity monoclonal antibodies bypassing the need for chimerization or humanization and affinity maturation of monoclonal antibodies raised in mice or other humanized systems. This work is supported by SBIR grants R44 CA 224718 and R44CA162729 from the National Cancer Institute to GS. Citation Format: Ginette Serrero, Jianping Dong, Binbin Yue, Mitsuo Oshimura, Chun Dong, Jun Hayashi. New generation of fully human anti-progranulin monoclonal antibodies inhibiting migration and tumor formation of non-small cell carcinoma cells [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 1864.

Quantitative immunochromatographic assay for rapid and cost-effective on-site detection of benzo[a]pyrene in oilfield chemicals

Contamination of oilfield chemicals (OFCs) by benzo[a]pyrene (B[a]P) is increasingly becoming a severe environmental security issue. There is an urgent need to develop a rapid and accurate method for B[a]P detection in OFCs. In this study, B[a]P hapten was designed using computer aided molecular design. A high-affinity, specific, and matrix-insensitive monoclonal antibody (mAb) with IC50 values of 6.77 ng/mL was obtained. Based on this mAb, we developed a rapid gold nanoparticle-based immunochromatographic strip assay (GICA) with double T-line mode for on-site detection of B[a]P in OFCs samples. The GICA exhibited excellent detection performance in OFCs samples with strong acidity, strong alkalinity, and deep color. Under optimal conditions, the proposed method detected B[a]P in OFCs at 0.42–300 mg/kg, and limit of detection was 0.23–1.07 mg/kg. The recovery rate was 88–106% with a coefficient of variation of 1.46–6.35%. Confirmed by natural positive OFCs samples and high-performance liquid chromatography, this GICA is accurate and reliable, with great potential for rapid and cost-effective on-site detection.

Claudin 18.2 as a novel therapeutic target.

Claudin 18.2, a tight-junction molecule predominantly found in the nonmalignant gastric epithelium, becomes accessible on the tumour cell surface during malignant transformation, thereby providing an appealing target for cancer therapy. Data from two phase III trials testing the anti-claudin 18.2 antibody zolbetuximab have established claudin 18.2-positive advanced-stage gastric cancers as an independent therapeutic subset that derives benefit from the addition of this agent to chemotherapy. This development has substantially increased the percentage of patients eligible for targeted therapy. Furthermore, newer treatments, such as high-affinity monoclonal antibodies, bispecific antibodies, chimeric antigen receptor T cells and antibody-drug conjugates capable of bystander killing effects, have shown considerable promise in patients with claudin 18.2-expressing gastric cancers. This new development has resulted from drug developers moving beyond traditional targets, such as driver gene alterations or growth factors. In this Review, we highlight the biological rationale and explore the clinical activity of therapies that target claudin 18.2 in patients with advanced-stage gastric cancer and explore the potential for expansion of claudin 18.2-targeted therapies to patients with other claudin 18.2-positive solid tumours.

Generation of a highly specific recombinant full-length antibody for detecting ethirimol in fruit and environmental water

High-performance antibodies are core reagents for highly sensitive immunoassays. Herein, based on a novel hapten, a hybridoma secreting the high-affinity anti-ethirimol monoclonal antibody (mAb-14G5F6) was isolated with an IC50 value of 1.35 μg/L and cross-reactivity below 0.20% for 13 analogs. To further address the challenge of hybridoma preservation and antibody immortalization, a recombinant full-length antibody (rAb-14G5F6) was expressed using the HEK293(F) expression system based on the mAb-14G5F6 gene. The affinity, specificity, and tolerance of rAb-14G5F6, as characterized by indirect competitive enzyme-linked immunosorbent assay and noncompetitive surface plasmon resonance, exhibited high concordance with those of mAb-14G5F6. Further immunoassays based on rAb-14G5F6 were developed for irrigation water and strawberry fruit with limits of detection of 0.0066 and 0.036 mg/kg, respectively, recoveries of 80100%, and coefficients of variation below 10%. Furthermore, homology simulation and molecular docking revealed that GLU(L40), GLY(L107), GLY(H108), and ASP(H114) play important roles in forming hydrogen bonds and pi-anion ionic bonds between rAb-14G5F6 and ethirimol, resulting in the high specificity and affinity of rAb-14G5F6 for ethirimol, with a KD of 5.71 × 10-10 mol/L. Overall, a rAb specific for ethirimol was expressed successfully in this study, laying the groundwork for rAb-based immunoassays for monitoring fungicide residues in agricultural products and the environment.

Screening high affinity monoclonal antibody producing hybridomas using a graphene oxide-based fluorescence biosensor

Screening monoclonal antibody (mAb) producing hybridomas by ELISA using microplates is time-consuming and expensive. The combination of biosensing and flow cytometry represents a promising rapid, high-throughput method for screening mAb producing clones. Based on the assembly of graphene oxide (GO) and fluorescein isothiocyanate (FITC)-labeled peptide that included the N-terminal portion of selenoprotein K (SELENOK) antigen epitope, we designed a novel GO fluorescence biosensor for screening high affinity mAb producing hybridomas. The FITC-labeled peptide was strongly adsorbed on the surface of GO, which effectively quenched the FITC fluorescence. The specific SELENOK mAb competitively bound to FITC-Peptide, resulting in FITC-Peptide release from the GO surface and fluorescence recovery. This sensor was successfully utilized to sensitively detect SELENOK mAb with low detection limit of 0.25 U. In addition, we employed this FITC-Peptide/GO biosensor to in situ visualizing and high-throughput screening SELENOK mAb hybridomas (SMAHs) at the single-cell level. The proposed sensor is simple, relatively inexpensive, highly specific, and applicable for cell sort assay, demonstrating the effective use for peptide-antibody interactions in the specific screening for other mAb hybridomas libraries.

Improving the diagnosis of active tuberculosis: a novel approach using magnetic particle-based chemiluminescence LAM assay

ObjectivesTuberculosis (TB) is a significant global health concern, given its high rates of morbidity and mortality. The diagnosis using urine lipoarabinomannan (LAM) primarily benefits HIV co-infected TB patients with low CD4 counts. The focus of this study was to develop an ultra-sensitive LAM assay intended for diagnosing tuberculosis across a wider spectrum of TB patients.Design & MethodsTo heighten the sensitivity of the LAM assay, we employed high-affinity rabbit monoclonal antibodies and selected a highly sensitive chemiluminescence LAM assay (CLIA-LAM) for development. The clinical diagnostic criteria for active TB (ATB) were used as a control. A two-step sample collection process was implemented, with the cutoff determined initially through a ROC curve. Subsequently, additional clinical samples were utilized for the validation of the assay.ResultsIn the assay validation phase, a total of 87 confirmed active TB patients, 19 latent TB infection (LTBI) patients, and 104 healthy control samples were included. Applying a cutoff of 1.043 (pg/mL), the CLIA-LAM assay demonstrated a sensitivity of 55.2% [95%CI (44.13%~65.85%)], and a specificity of 100% [95%CI (96.52%~100.00%)], validated against clinical diagnostic results using the Mann-Whitney U test. Among 11 hematogenous disseminated TB patients, the positive rate was 81.8%. Importantly, the CLIA-LAM assay consistently yielded negative results in the 19 LTBI patients.ConclusionOverall, the combination of high-affinity antibodies and the CLIA method significantly improved the sensitivity and specificity of the LAM assay. It can be used for the diagnosis of active TB, particularly hematogenous disseminated TB.