Combination Of Monoclonal Antibodies Research Articles

Developing a human monoclonal antibody combination CRM25 to prevent rabies after exposure.

Immunization against rabies post-exposure prophylaxis (PEP) requires passive immunization with either monoclonal antibody (mAb) or blood-derived rabies immunoglobin (RIG). Currently, replacing traditional RIG with emerging mAb or mAb combinations is highly recommended due to the limited supply and potential safety risks of RIG. Here, we developed a mAb combination named CRM25 by combining two human mAbs, RM02 and RM05, at a 1:1 mass ratio. RM02 and RM05 were non-competing and non-overlapping mAbs targeting epitopes I and III, respectively. K226 and G229 were found to be the critical amino acid sites for RM02 neutralization, but the mutant I338T displayed decreased susceptibility to RM05 neutralization. Notably, CRM25 was capable of cross-neutralizing rabies virus (RABV) strains containing K226M or I338T mutations. CRM25 additionally showed an inhibitory effect on the infection of all tested common RABVs and non-RABV phylogroup I lyssaviruses. CRM25 not only exhibited neutralizing activity but also exhibited antiviral effects via Fc-mediated effector functions. Importantly, CRM25 was comparable to human RIG in terms of its capacity to protect Syrian golden hamsters from lethal RABV challenges. These findings promote more thorough research on CRM25's antiviral properties in cells and in vivo to enhance its clinical applicability and suggest that it may be a viable candidate medication for rabies PEP.

The effect of combination treatment with casirivimab and imdevimab versus standard antiviral therapy on clinical outcomes in hospitalized COVID-19 patients

BackgroundThe Coronavirus Disease of 2019 (COVID-19) pandemic motivated research efforts to address this catastrophe from the beginning of 2020 to the present. The year 2021 is coming to an end, and several developments in pharmacotherapy for COVID-19 have occurred. In terms of antiviral therapy, monoclonal antibody combinations have become one type of COVID-19 immunotherapy. Remdesivir and favipiravir are two antiviral medications typically used to treat COVID-19. Paxlovid (nirmatrelvir plus ritonavir) and molnupiravir are other antiviral agents used in COVID-19. The purpose of this study was to compare the effects of combinations of antibodies (casirivimab and imdevimab), remdesivir, and favipiravir on COVID-19 swab results in hospitalized patients with COVID-19 at discharge.MethodsThis research is a phase IV non-randomized controlled trial (< 300 patients as sample size) with no comparison to placebo. In this study, 265 COVID-19 patients confirmed by polymerase chain reaction (PCR) and indications for antiviral medication were non-randomized into three groups at a ratio of (1:2:2): REGN3048-3051 (group A), remdesivir (group B), and favipiravir (group C). A nonrandomized single-blind controlled study design was used. The study's medication was provided by the Hospital of Mansoura University. Following ethical approval, the study was conducted for approximately 6 months.ResultsCompared to remdesivir and favipiravir, casirivimab and imdevimab cause less hepatotoxicity, less renal impairment, and more negative swab results at discharge. The three tested antivirals also had no significant adverse effects. All three antivirals are considered safe based on these findings.ConclusionCompared with remdesivir and favipiravir, casirivimab and imdevimab result in better clinical outcomes. All three antivirals are safe and have no significant toxicity.Trial registration: Clinicaltrials.gov, NCT05502081, 16/08/2022.

Safety of intramuscular tixagevimab-cilgavimab (Evusheld®) administration in patients at risk of iatrogenic haematoma due to haematological disorders.

Traditionally, intramuscular (IM) injections have been avoided in patients with haematological diseases due to the risk of iatrogenic haematoma. Tixagevimab-cilgavimab (Evusheld®) is a novel monoclonal antibody combination used as preexposure prophylaxis against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), for those at highest risk of severe infections. It is delivered as two separate IM injections (1.5 mL each). Patients with haematological disease are at higher risk for severe SARS-CoV-2 infections, which may be partially abrogated by the prophylactic inoculation of tixagevimab-cilgavimab. A combined retrospective and prospective study of patients under the haematology service at a large metropolitan hospital receiving tixagevimab-cilgavimab was conducted. Tixagevimab-cilgavimab was administered IM to all patients, with platelet and factor replacement provided according to local protocols. Patients completed a numerical pain score daily for seven days following the injection, with scores ≥4/10 prompting an ultrasound to identify iatrogenic gluteal haematomas. The study recruited 131 patients; 66 patients were thrombocytopenic, including 10 patients with a platelet count <30 × 109/L. Fourteen patients (10.7%) received a single platelet transfusion prior to tixagevimab-cilgavimab administration, while two patients received fresh frozen plasma. No gluteal haematomas were identified, and only two patients reported an initial pain score of ≥4/10. The intramuscular administration of tixagevimab-cilgavimab in patients with haematological diseases was well tolerated and was not associated with iatrogenic haematoma.

Activity of cellular immunity in patients with nutrition-dependent diseases (obesity, type 2 diabetes)

The purpose of the study is to analyze the indicators of cellular immunity in patients with obesity (OB) and type 2 diabetes mellitus (DM2). The study included 15 patients with DM2 (DM2 group), body mass index (BMI) 37.36±1.12 kg/m2, 12 patients with OB (OB group), BMI – 38.12±1.51 kg/m2 and 15 practically healthy individuals (comparison group – GС): BMI 23.5±0.15 kg/m2. The study was performed on a flow cytometer FC-500 (Beckman Coulter, USA) using double combinations of monoclonal antibodies (Beckman Coulter – Immunotech SAS, France). The percentage indicators of the T cell population were assessed, such as total number of T lymphocytes (CD3+), number of T helper cells (CD3+CD4+), cytotoxic T lymphocytes (CD3+CD8+), natural killer cells – NK cells (CD3-CD16+CD56+), natural killer cells with the properties of T lymphocytes – NKT cells (CD3+CD16+CD56+) and B cell population (CD19+) lymphocytes, as well as the relative content of lymphocytes carrying activation markers (CD3+HLA-DR+, CD3+CD25+), and apoptosis marker antigen CD45+CD95+. The relative content of B lymphocytes and T lymphocytes in the peripheral blood of the examined individuals did not have statistically significant differences. In patients in the DM2 and OB groups, there was a tendency (p 0.1) towards an increase in the relative content of T helper cells and a significant (p 0.05) decrease in the percentage of T cytotoxic lymphocytes relative to GC. This redistribution of lymphocyte subpopulations led to a significant (p 0.05) increase in the IRI value (arbitrary units): DM2 – 2.87±0.58; OB – 2.30±0.33 vs GC – 1.62±0.15. The relative content of NK cells and NKT cells in the peripheral blood of the examined individuals did not have a statistically significant difference in the magnitude of the indicators. A statistically significant (p 0.05) increase in the relative content of T lymphocytes expressing the activation marker HLA-DR (CD3+HLA-DR+) was found in patients in the DM2 and OB groups relative to GC [(%) DM2 – 7.95±0, 81; OB – 6.54±0.24; GC – 4.01±0.91] and a significant (p 0.05) increase in the percentage of CD45+CD95+ lymphocytes in patients with OB and DM2 relative to GC [(%) DM2 – 5.84±0.68; OB – 5.16±0.89; GC – 2.78±0.34]. The results obtained indicate the presence of meta-inflammation in patients with DM2 and OB.

Tixagevimab/Cilgavimab for COVID-19 Pre-Exposure Prophylaxis in Hematologic Patients-A Tailored Approach Based on SARS-CoV-2 Vaccine Response.

Patients with hematologic malignancies still face a significant risk of severe coronavirus disease 2019 (COVID-19). The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2)-neutralizing monoclonal antibody combination tixagevimab/cilgavimab (TIX/CGB) could be administered to immunocompromised patients for pre-exposure prophylaxis (PrEP) before the emergence of TIX/CGB-resistant COVID-19 Omicron variants. TIX/CGB application could be carried out regardless of the host's immune response to previous active SARS-CoV-2 vaccinations or infections. Because the efficacy of COVID-19 PrEP remains unclear, especially in SARS-CoV-2-seropositive patients, German national guidelines recommended TIX/CGB PrEP only for SARS-CoV-2-seronegative patients in addition to an intensified active vaccination schedule. Having followed these guidelines, we now report the characteristics and outcomes of 54 recipients of TIX/CGB PrEP in SARS-CoV-2-seronegative patients with hematological disease from a German tertiary medical center and compare them to 125 seropositive patients who did not receive any PrEP. While the number of patients with B-cell lymphomas was significantly higher in the seronegative cohort (33 (61%) vs. 18 (14%) cases, p < 0.01), patients with myeloid diseases were significantly more frequent in the seropositive cohort (51 (41%) vs. 5 (9%) cases, p < 0.01). Strikingly, patients who had undergone allogeneic hematopoietic stem cell transplantation were significantly more likely (forty-nine (39%) vs. six (11%) cases, p < 0.01) to be SARS-CoV-2 seropositive. We observed that prophylactic application of TIX/CGB PrEP to a highly vulnerable group of SARS-CoV-2-seronegative patients resulted in a similar number of COVID-19 breakthrough infections compared to the untreated seropositive control group (16 (32%) vs. 39 (36%), p = 0.62) and comparable COVID-19-related outcomes like hospitalization and oxygen requirement throughout an extended follow-up period of 12 months. In conclusion, our results support the tailored approach of administering TIX/CGB PrEP only to SARS-CoV-2-seronegative patients during the COVID-19 pandemic and might provide a rationale for similar strategies during future outbreaks/diseases, especially in times of initial limited availability and/or financial constraints.

Dual neutralization of influenza virus hemagglutinin and neuraminidase by a bispecific antibody leads to improved antiviral activity

Targeting multiple viral proteins is pivotal for sustained suppression of highly mutable viruses. In recent years, broadly neutralizing antibodies that target the influenza virus hemagglutinin and neuraminidase glycoproteins have been developed, and antibody monotherapy has been tested in preclinical and clinical studies to treat or prevent influenza virus infection. However, the impact of dual neutralization of the hemagglutinin and neuraminidase on the course of infection, as well as its therapeutic potential, has not been thoroughly tested. For this purpose, we generated a bispecific antibody that neutralizes both the hemagglutinin and the neuraminidase of influenza viruses. We demonstrated that this bispecific antibody has a dual antiviral activity as it blocks infection and prevents the release of progeny viruses from the infected cells. We show that dual neutralization of the hemagglutinin and the neuraminidase by a bispecific antibody is advantageous over monoclonal antibody combination as it resulted an improved neutralization capacity and augmented the antibody effector functions. Notably, the bispecific antibody showed enhanced antiviral activity in influenza virus-infected mice, reduced mice mortality and limited the virus mutation profile upon antibody administration. Thus, dual neutralization of the hemagglutinin and neuraminidase could be effective in controlling influenza virus infection.

FXa-mediated PAR-2 promotes the efficacy of immunotherapy for hepatocellular carcinoma through immune escape and anoikis resistance by inducing PD-L1 transcription

BackgroundThe high metastasis rate is one of the main reasons for the poor prognosis of patients with hepatocellular carcinoma (HCC). Coagulation factor Xa (FXa) and its receptor proteinase-activated receptor-2 (PAR-2)...

Ronapreve (REGN-CoV; casirivimab and imdevimab) reduces the viral burden and alters the pulmonary response to the SARS-CoV-2 Delta variant (B.1.617.2) in K18-hACE2 mice using an experimental design reflective of a treatment use case.

With some exceptions, global policymakers have recommended against the use of existing monoclonal antibodies in COVID-19 due to loss of neutralization of newer variants. The purpose of this study was to investigate the impact of Ronapreve on compartmental viral replication using paradigms for susceptible and insusceptible variants. Virological efficacy and impact on pathogenicity was assessed in K18-hACE2 mice inoculated with either the Delta or BA.1 Omicron variants. Ronapreve reduced sub-genomic viral RNA levels in lung and nasal turbinate, 4 and 6 days post-infection, for the Delta variant but not the Omicron variant. It also blocked brain infection, which is seen with high frequency in K18-hACE2 mice after Delta variant infection. At day 6, the inflammatory response to lung infection with the Delta variant was altered to a multifocal granulomatous inflammation in which the virus appeared to be confined. The current study provides evidence of an altered tissue response to SARS-CoV-2 after treatment with a monoclonal antibody combination that retains neutralization activity. These data demonstrate that experimental designs that reflect treatment use cases are achievable in animal models for monoclonal antibodies. Extreme caution should be taken when interpreting prophylactic experimental designs that may not be representative of treatment.IMPORTANCEFollowing the emergence of the SARS-CoV-2 Omicron variant, the WHO recommended against the use of Ronapreve in its COVID-19 treatment guidelines due to a lack of efficacy based on current pharmacokinetic-pharmacodynamic understanding. However, the continued use of Ronapreve, specifically in vulnerable patients, was advocated by some based on in vitro neutralization data. Here, the virological efficacy of Ronapreve was demonstrated in both the lung and brain compartments using Delta as a paradigm for a susceptible variant. Conversely, a lack of virological efficacy was demonstrated for the Omicron variant. Comparable concentrations of both monoclonal antibodies were observed in the plasma of Delta- and Omicron-infected mice. This study made use of a reliable murine model for SARS-CoV-2 infection, an experimental design reflective of treatment, and demonstrated the utility of this approach when assessing the effectiveness of monoclonal antibodies.

Patient-Reported Outcomes in COVID-19 Treatment with Monoclonal Antibodies Reveal Benefits in Return to Usual Activities.

This study aimed to assess the effects of a monoclonal antibody (mAb) combination on symptoms, daily function, and overall health-related quality of life. We analyzed patient-reported outcomes data from symptomatic outpatients in a phase1/2/3 trial. Patients with confirmed SARS-CoV-2 infection and ≥ 1 risk factor for severe COVID-19 received mAb treatment (casirivimab plus imdevimab 1200mg) or placebo. Prespecified exploratory assessments included time to sustained symptoms resolution, usual health, and return to usual activities (assessed daily for 29days). The trial was conducted from September 2020 to February 2021, prior to widespread COVID-19 vaccination programs and Omicron-lineage variants against which casirivimab + imdevimab is not active. In this analysis 736 outpatients received mAb and 1341 received placebo. Median time to sustained symptoms resolution was consistently shorter with mAb versus placebo (≥ 2consecutive days: 14 vs 17days, [nominal p = 0.0017]; ≥ 3 consecutive days: 17vs 21days, [nominal p = 0.0046]). Median time to sustained return to usual health and usual activities were both consistently shorter with mAb versus placebo (≥ 2 consecutive days: 12vs 15days [nominal p = 0.0001] and 9 vs 11days [nominal p = 0.0001], respectively; ≥ 3 consecutive days: 14 vs 18days [nominal p = 0.0003] and 10 vs 13days [nominal p = 0.0041], respectively). mAb treatment against susceptible SARS-CoV-2 strains improved how patients feel and function, as evidenced by shortened time to sustained symptoms resolution and return to usual health and activities. Future studies are warranted to assess the patient experience with next generation mAbs. GOV: Registration number, NCT04425629; Submission date June 11, 2020.

Efficacy and safety of casirivimab and imdevimab for preventing and treating COVID-19: a systematic review and meta-analysis.

The ongoing global epidemic of coronavirus disease 2019 (COVID-19) has created a serious public health problem. The selection of safe and effective therapeutic agents is of paramount importance. This systematic review aims to evaluate the efficacy and safety of the combination of casirivimab and imdevimab in the treatment of global cases of COVID-19. To identify randomized controlled trials (RCTs) investigating the combined administration of casirivimab and imdevimab for COVID-19 management, a comprehensive search was conducted across multiple databases including PubMed, Web of Science, Embase, and the Cochrane Library from their inception to September 10, 2022. Data on the efficacy and safety of casirivimab and imdevimab were extracted. Subgroup analyses and sensitivity analyses were performed. A total of 851 articles were searched. Twelve studies were finally included in the meta-analysis, with 27,179 participants. Dichotomous and continuous variables were presented as odds ratios (ORs) and weighted mean differences (WMDs) with their 95% confidence intervals (CIs), respectively. Compared to placebo or alternative medications, the combination of casirivimab and imdevimab reduced viral load (WMD: -0.73, 95% CI: -1.09 to -0.38, P<0.01), all-cause mortality (OR =0.90, 95% CI: 0.82-0.99, P=0.03), the incidence of any serious adverse events (OR =0.80, 95% CI: 0.67-0.95, P=0.01), the incidence of Grade 3 or more severe adverse events (OR =0.76, 95% CI: 0.62-0.92, P=0.01), the likelihood of contracting COVID-19, the incidence of hospitalization, emergency room visits, and mortality (OR =0.54, 95% CI: 0.32-0.93, P=0.03). The monoclonal antibody combination of casirivimab and imdevimab is effective in treating patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as they can reduce viral load, all-cause mortality, infection rates, and the incidence of clinical outcomes of special interest after treatment, while maintaining a favorable safety profile.

Comprehensive procedure for injecting Evusheld® for hematological diseases in a single institute.

Tixagevimab and cilgavimab (EVA, Evusheld®), monoclonal antibody combination treatments, consisted of two neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). EVA showed prophylactic and therapeutic effects against coronavirus disease 2019. The Japanese Society of Hematology recommended EVA for such patients with active treatment, but each institution decided on comprehensive administration. We develop a systematic procedure for comprehensive EVA injection prophylactically in patients with hematological malignancies without any over/under-indication. We listed all patients with the required indications from November 2022 to March 2023. We included 178 cases, 84 females and 94 males, with a median age of 70 (range: 19-90) years. Underlying diseases are myeloid neoplasms in 36 (20%), lymphoid neoplasms in 75 (73%), and others. Indications were intensively hematological malignancy treatment, rituximab treatment within 12months, burton kinase inhibitor treatment, after chimeric antigen receptor T cell immunotherapy, and after stem cell transplantation in 74 (41%), 73 (41%), 3 (2%), 5 (3%), and 23 (13%) cases, respectively. Of the 178 cases, 22 (12.4%) refused EVA injection. Further, 42 and 136 cases were administered outpatient and inpatient, respectively. Over 95% of the listed cases received EVA injection within 3months. No severe toxicities were observed among them (N = 156), and 8 (5.2%) cases had breakthrough SARS-CoV-2 infection, which was significantly lower (P = 0.02) than those without EVA (4 [18.2%] of 22 cases). Both groups showed no moderate or severe infection cases. This single-center experience showed that comprehensive EVA injection management effectively generated safer completion with preferable clinical impact.

Preparation and application of fluorescent monoclonal antibodies recognizing goat CD4+CD25+ regulatory T cells

Regulatory T cells (Tregs) are a subset of T cells participating in a variety of diseases including mycoplasmal pneumonia, contagious ecthyma, and so on. The role of Tregs in goat contagious ecthyma is not completely understood due to the lack of species-specific antibodies. Here, we developed a combination of CD4 and CD25 fluorescence monoclonal antibodies (mAb) to recognize goat Tregs and assessed its utility in flow cytometry, immunofluorescence staining. Using immunofluorescence staining, we found that the frequency of Treg cells was positively correlated with the viral load during orf virus infection. These antibodies could serve as important tools to monitor Tregs during orf virus infection in goats.Key points• A combination of fluorescent mAbs (C11 and D12) was prepared for the detection of goat Tregs.• C11 and D12 are effective in flow cytometry, immunofluorescence staining, and C11 has excellent species specificity.• The frequency of Treg cells was positively correlated with the viral load during orf virus infection.

Oral Domiciliary Therapy of Multiple Myeloma with Cyclophosphamide, Pomalidomide and Dexamethasone Regimen in the Covid Era - A Pilot Study

Background: Multiple myeloma is the 11th most common cancer in India, with a prevalence of 1.1% and a diagnosis age range of 65 to 74 years. Various doublet or triplet combinations of steroids, immunomodulatory medications, proteasome inhibitors, and monoclonal antibodies are used in standard myeloma therapy. Covid 19 pandemic has been extremely challenging especially when it comes to the management of cancer patients. As the incidence of multiple myeloma (MM) is increasing rapidly in Asian countries, and the Asian patients seem to respond differently compared to the western population to the various commonly used treatment regimens, these patients require special consideration and care to ensure optimum treatment and at the same time, precautions must be taken to decrease their exposure to COVID-19. Considering these aspects, we decided to use an all-oral treatment of CyPomDexa (Cyclophosphamide, Pomalidomide and Dexamethasone) for the treatment of myeloma both as a first-line regimen as well as for relapsed and refractory patients who had not been exposed to this regimen in the past, and to observe the feasibility and efficacy of domiciliary, oral treatment with cyclophosphamide, pomalidomide and dexamethasone (Cy-Pom-Dex) for myeloma patients during the COVID-19 pandemic. Methods: A Prospective, observational, single-arm, pilot study was conducted from 1st March 2020 to 30th September 2020 in patients who were newly-diagnosed (NDMM) or relapsed multiple myeloma (RMM) at a tertiary care Centre in Bengaluru. The patients were started on oral treatment with CyPomDexa during lockdown mandated by the COVID-19 pandemic. This regimen was chosen as a replacement for cyclophosphamide, bortezomib, dexamethasone (CyBorD), which was the previous standard of care in our centre. Haematological and biochemical parameters of the patients were checked pre-treatment. Weekly complete blood counts and biochemistry was checked with home collection of blood samples. This was combined with weekly video consultations. Face-to-face visits were conducted monthly, and myeloma parameters were checked at the end of every 2 months. Results: 6 patients underwent the planned treatment. Among these 4 had NDMM and 2 had RMM. 1 patient who received CyPomDexa from the first cycle was lost to follow-up (COVID 19 positive). Among the remaining 5 patients ,3 (50%) achieved VGPR (very good partial response) and 2 (33.33%) achieved SCR (Stringent Complete Response) after 4 cycles of therapy. Conclusion: This regimen achieved good disease control in all the evaluable patients, within 4 cycles. A larger, prospective study is however required to draw definitive conclusions.

A Novel Nomogram to Predict Prognosis of Advanced Hepatocellular Carcinoma Treated with Intensity-Modulated Radiotherapy Plus Anti-PD1.

The combination of radiotherapy and monoclonal antibody against programmed cell death 1 (anti-PD1) showed preliminary efficacy in hepatocellular carcinoma (HCC). This study aimed to identify the prognostic factors and construct a nomogram to predict the overall survival (OS) of patients with advanced HCC after treatment with intensity-modulated radiotherapy (IMRT) plus anti-PD1. The OS and progression-free survival (PFS) of 102 patients with BCLC stage C HCC was analyzed using the Kaplan-Meier method. Potential independent prognostic factors were determined using univariate and multivariate Cox regression analyses. A nomogram was established to predict prognosis whose accuracy and reliability was verified by a calibration curve and area under the receiver operating characteristic curve (AUROC). The median PFS and OS rates of the 102 patients with advanced HCC were 9.9 months and 14.3 months, respectively. Ninety-three patients were evaluated for efficacy, including five (5.38%) with complete response and 48 (51.61%) with partial response, with an overall response rate of 56.99%. Grade 3 and 4 adverse reactions (AEs) were observed in 32.35% of patients; no grade 5 AEs occurred. Multivariate Cox analysis revealed albumin and alpha-fetoprotein levels, neutrophil counts 3-4 weeks after IMRT initiation, and platelet-to-lymphocyte ratio 3-4 weeks after IMRT initiation to be independent prognostic factors. The nomogram model constructed using these factors had good consistency and accuracy with 1-3 years AUROC of 78.7, 78.6, and 93.5, respectively. IMRT plus anti-PD1 showed promising efficacy and controllable adverse reactions in treating advanced HCC. The nomogram model demonstrated good reliability and clinical applicability.

Concurrent simultaneous integrated boost radiotherapy and cetuximab in head and neck squamous cell cancer patients: is it feasible in daily clinical practice?

Locally advanced head and neck squamous cell carcinoma (LA-Hnscc) is a true therapeutical challenge in the modern era and the scientific community is trying to face this challenge with new therapeutical strategies, including combinations of monoclonal antibodies and radiation therapy. The aim of this study is to evaluate clinical outcomes in LA-Hnscc patients unfit to receive platinum-based chemotherapy, treated with concurrent simultaneous integrated boost-intensity modulated radiotherapy (Sib-Imrt) + cetuximab (Ctx) in daily clinical practice. LA-Hnscc patients not included in other prospective studies treated in 4 Italian radiotherapy units (2 Messina, 1 Rome, and 1 Lecce) using Sib-Imrt and Ctx were included in this study. Acute and late toxicities and overall survival (OS) have been evaluated. Data regarding 27 patients with squamous tumour were collected and reviewed. The primary tumour sites were oropharynx in 14 patients (51.9%), oral cavity in 7 (25.9%), larynx in 3 (11%) and other sites in 3(11%). There were 20 (74%) patients had stage IV (16 IVa and 4 IVb). Complete remission was observed in 18 patients (66.7%), a partial remission in 4 (14.8%) whilst 4 had a progression disease (14.8%). After 3 year of follow-up 7/27 patients were deaths. The OS was 95.5%, 62.5% and 52.9% respectively at 1,2 and 3 years. Acute toxicities were observed in all treated patients (mucositis, dermatitis and dysphagia) while 66.7% of patients developed late toxicities. All observed toxicities were grade 1 to 3 and just 1 patient developed a G4 toxicity. The concurrent bio-radiotherapy of Sib-Imrt and cetuximab is feasible in real-life daily clinical practice for LA-Hnscc patients unfit for platinum-based chemoradiotherapy.

Antiviral and Monoclonal Antibody Combination Therapy in Haematological Patients in the Omicron Era.

Abstract: Im We describe here a single-center case series of 27 IC COVID-19 inpatients (mostly with haematological disorders) treated with a combined therapy based on tixagevimab/cilgavimab (T/C) plus small-molecule antivirals (AV), between April 1 2022 and November 30 2022. Keywords: immunocompromised; SARS-CoV-2 infection; monoclonal antibodies; antivirals; persistent infection; viral evolution

Use of in silico approaches, synthesis and profiling of Pan-filovirus GP-1,2 preprotein specific antibodies.

Intermolecular interactions of protein-protein complexes play a principal role in the process of discovering new substances used in the diagnosis and treatment of many diseases. Among such complexes of proteins, we have to mention antibodies; they interact with specific antigens of two genera of single-stranded RNA viruses belonging to the family Filoviridae-Ebolavirus and Marburgvirus; both cause rare but fatal viral hemorrhagic fever in Africa, with pandemic potential. In this research, we conduct studies aimed at the design and evaluation of antibodies targeting the filovirus glycoprotein precursor GP-1,2 to develop potential targets for the pan-filovirus easy-to-use rapid diagnostic tests. The in silico research using the available 3D structure of the natural antibody-antigen complex was carried out to determine the stability of individual protein segments in the process of its formation and maintenance. The computed free binding energy of the complex and its decomposition for all amino acids allowed us to define the residues that play an essential role in the structure and indicated the spots where potential antibodies can be improved. Following that, the study involved targeting six epitopes of the filovirus GP1,2 with two polyclonal antibodies (pABs) and 14 monoclonal antibodies (mABs). The evaluation conducted using Enzyme Immunoassays tested 62 different sandwich combinations of monoclonal antibodies (mAbs), identifying 10 combinations that successfully captured the recombinant GP1,2 (rGP). Among these combinations, the sandwich option (3G2G12* - (rGP) - 2D8F11) exhibited the highest propensity for capturing the rGP antigen.

Neutralization sensitivity of SARS-CoV-2 Omicron variants FL.1 and GE.1 by therapeutic antibodies and XBB sera

Two SARS-CoV-2 XBB sub-variants, FL.1 and GE.1, have been increasing in prevalence worldwide, but limited information is available about their ability to evade the immune system. FL.1 and GE.1 are emerging Omicron XBB variants possessing additional mutations in the spike RBD raising concerns of increased neutralization escape. In this study, we assessed the neutralizing ability of eleven FDA-approved monoclonal antibody combinations against different Omicron variants, including BA.2.75, BA.2.76, BA.4/5, XBB.1.5, and CH.1.1. Among the eleven antibodies, Sotrovimab was the only antibody to show broad neutralization ability against XBB.1.5. However, Sotrovimab showed attenuated neutralization efficiency against recently emerging XBB sub-lineages EG.5, FL.1, and GE.1 compared to XBB.1.5. Additionally, XBB.1.5 seropositive convalescent sera displayed lower neutralization activity against EG.5, FL.1, and GE.1. Overall, our findings present enhanced immune evasion capacity of emerging XBB variants and emphasize the importance of continued monitoring of novel variants.

Abstract 2733: NB202: A bispecific anti-PD1/TIM-3 antibody for cancer immunotherapy

Abstract Despite the remarkable efficacy of PD-(L)1 therapy, a significant proportion of cancer patients fail to respond or develop resistance over time. Co-expression of T-cell immunoglobulin and mucin domain containing-3 (TIM-3) with PD-1 on primed T cells has been observed in patients exhibiting resistance to PD-1 blockade. Moreover, TIM-3 is also expressed on other immune cells, including NK and DC, and plays a negative regulatory role in these immune cells. Therefore, the dual blockade of PD-1 and TIM-3 holds potential for enhanced clinical benefits. NB202 is a bispecific anti-PD1/TIM-3 antibody that has been designed to optimize the therapeutic response of anti-PD1 therapy by maximizing TIM-3 blockade on antigen-experienced T cells, enhancing NK cell activity, and improving antigen presentation ability of antigen-presenting cells (APC). NB202 has demonstrated high affinity binding to human TIM3 and PD-1 in the low nanomolar range. Moreover, it can simultaneously bind to TIM-3 and PD-1 receptors through a trans-manner, suggesting its potent capacity to enhance the interaction between T cells and dendritic cells (DCs). In classic MLR (mixed lymphocyte reaction) and T cell stimulation assays, NB202 has exhibited superior efficacy compared to the combination of anti-PD1 mAb and anti-TIM3 monoclonal antibodies as it significantly enhances the secretion level of interferon-gamma (IFN-gamma), and particularly interleukin-2 (IL-2). Moreover, in an anti-PD1 resistant mouse model, NB202 has shown promising efficacy results. Citation Format: Jinyu Dong, Yu Zhang, Binbin Wang, Dong Wang, Tingting Bu, Jie Ni, Bishnu Nayak, Xin Dong. NB202: A bispecific anti-PD1/TIM-3 antibody for cancer immunotherapy [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 2733.

Abstract 2712: Development of GB268, a tri-specific antibody targeting PD-1/CTLA-4/VEGF, with enhanced anti-tumor efficacy and reduced toxicity in pre-clinical studies

Abstract Background: Immunotherapy using immune checkpoint modulators such as anti-PD1/PD-L1 have been widely used in cancer therapy. Combination of checkpoint inhibition using anti-PD1 and anti-CTLA4 has improved therapeutic efficacy but is also accompanied by severe immune related adverse events (irAEs) which limited their clinical use. Bi-specific antibody targeting PD-1/CTLA-4 such as cadonilimab has shown improved clinical benefits with reduced irAEs in cervical cancer. Vascular endothelial growth factor (VEGF) is overexpressed in various solid tumors and anti-VEGF agents inhibit neovascularization and shrink tumor with time. Combined application of bevacizumab and PD-1/PD-L1 blockade displays durable and improved anti-tumor effects. We have recently developed a novel tri-specific antibody GB268, specifically targeting PD-1, CTLA-4 and VEGF with fine-tuned activity &amp; potency for each arm to simultaneously block PD-1/CTLA-4 mediated immune-suppression and VEGF mediated tumor angiogenesis. Methods: GB268 is a hexavalent antibody with symmetrical structure, composed of anti-PD-1 VHH antibody, anti-CTLA-4 VHH antibody, and anti-VEGF conventional antibody. The Fc part is silenced by introducing L234A/L235A mutations. Comprehensive in vitro and in vivo characterization of GB268 have been carried out. Along with in vivo efficacy studies, toxicity has also been evaluated with a murine arthritis model in hPD1/hCTLA4 double-KI mice to assess immune related AEs. Results: GB268 specifically bound to PD-1, VEGF, and CTLA-4 with high affinity and completely blocked PD-1 and VEGF pathways in reporter systems. To reduce the CTLA4 inhibition-induced AEs, the CTLA-4 arm was intentionally designed to only partially block the interaction of CTLA4 to its ligands CD80/CD86, and furthermore, the blockade of CTLA-4 was highly dependent on PD-1 expression. GB268 displayed robust anti-tumor efficacy with attenuated toxicity in murine models. In multiple PBMC-humanized models including A375 melanoma model, HT29 colorectal cancer model, and NCI-H460 NSCLC model, etc., GB268 exhibited significantly better anti-tumor efficacy, compared to PD-1/CTLA-4 bsAb and PD-1/VEGF bsAb, or in the combination of monoclonal antibodies to PD-1, CTLA-4 or VEGF. In arthritis induction model using hPD1/hCTLA4 double KI mice, GB268 had improved tolerance than cadonilimab and at least 20-fold better safety profile than ipilimumab combined with nivolumab. Conclusions: GB268 is a first-in-class anti-PD-1/CTLA-4/VEGF tri-specific antibody with innovative design. Preclinical data demonstrated GB268 is very effective in provoking anti-tumor responses. At the meantime, immune-related AEs is alleviated. Thus, GB268 may emerge as a promising novel therapeutics for cancer treatment. Citation Format: Qinglin Du, Yaxua Lv, Juehua Xu, Fei Peng, Huanhuan Cao, Xueyan Yang, Zhen Qian, Xueqin Li, Yiqi Cao, Qian Ding, Yongcong Tan, Shuhua Han. Development of GB268, a tri-specific antibody targeting PD-1/CTLA-4/VEGF, with enhanced anti-tumor efficacy and reduced toxicity in pre-clinical studies [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 2712.