Crohn’s disease is an inflammatory bowel disease (IBD) commonly treated through anti-TNF blockade. However, most patients still relapse and inevitably progress. Comprehensive single-cell RNA-sequencing (scRNA-seq) atlases have largely sampled patients with established treatment-refractory IBD, limiting our understanding of which cell types, subsets, and states at diagnosis anticipate disease severity and response to treatment. Here, through combining clinical, flow cytometry, histology, and scRNA-seq methods, we profile diagnostic human biopsies from the terminal ileum of treatment-naïve pediatric patients with Crohn’s disease (pediCD; n=14), matched repeat biopsies (pediCD-treated; n=8) and from non-inflamed pediatric controls with functional gastrointestinal disorders (FGID; n=13). To resolve and annotate epithelial, stromal, and immune cell states among the 201,883 baseline single-cell transcriptomes, we develop a principled and unbiased tiered clustering approach, ARBOL. Through flow cytometry and scRNA-seq, we observe that treatment-naïve pediCD and FGID have similar broad cell type composition. However, through high-resolution scRNA-seq analysis and microscopy, we identify significant differences in cell subsets and states that arise during pediCD relative to FGID. By closely linking our scRNA-seq analysis with clinical meta-data, we resolve a vector of T cell, innate lymphocyte, myeloid, and epithelial cell states in treatment-naïve pediCD (pediCD-TIME) samples which can distinguish patients along the trajectory of disease severity and anti-TNF response. By using ARBOL with integration, we position repeat on-treatment biopsies from our patients between treatment-naïve pediCD and on-treatment adult CD. We identify that anti-TNF treatment pushes the pediatric cellular ecosystem towards an adult, more treatment-refractory state. Our study jointly leverages a treatment-naïve cohort, high-resolution principled scRNA-seq data analysis, and clinical outcomes to understand which baseline cell states may predict Crohn’s disease trajectory.

BACKGROUND:It has long been appreciated that multiple allergic/atopic conditions (type-2-inflammation-associated diseases, T2IDs) often appear in the same individual, suggesting a shared systemic immune deviation. Emerging molecular and clinical investigations of interleukin (IL)4/IL13 blockade with the fully-human antibody dupilumab suggest that many are driven by over-activation of the IL4/IL13 pathway, manifesting differently in distinct tissues. METHODS AND RESULTS:We performed comprehensive quantitative analyses using several large, independent datasets (including real-world and clinical trial datasets) to confirm that many T2IDs-including asthma, atopic dermatitis, eosinophilic esophagitis, nasal polyps, prurigo nodularis-are highly interrelated based on co-prevalence, genetic predispositions, and transcriptomic signatures driven by over-activation of the IL4/IL13 pathway. We also summarize extensive clinical trial data showing that these T2IDs also share uniformly impressive clinical responses to dual IL4/IL13 blockade with dupilumab. CONCLUSIONS:While highly consistent with previous data and observations, this is the first systematic comparison of these types of data across multiple T2IDs, using a rigorous quantitative assessment of the largest datasets evaluated to date. Many T2IDs are not only highly interrelated and comorbid, but share transcriptomic signatures and genetic predispositions that suggest they all share over-activation of the IL4/IL13 pathway as a key causative driver, consistent with and explaining their uniform clinical responsiveness to dual IL4/IL13 blockade. These genetic and transcriptomic signatures may also have utility for identifying other diseases mediated by IL4/IL13 or T2-mediated subpopulations of heterogenous inflammatory diseases.

Background Deeper insight is needed on how monoclonal antibodies (mAbs) affect vaccine-mediated immune responses when targeting the same protein. We describe the first prospective randomised trial designed to understand mAb-mediated alterations in vaccine-induced immune responses to SARS-CoV-2 spike protein epitopes. Methods This randomised, open-label, parallel-group study assessed the potential interaction of a mAb combination, casirivimab and imdevimab, with a vaccine, Moderna's mRNA-1273, in healthy SARS-CoV-2 immunologically naive, seronegative adults at six centres in the USA. Participants were randomly assigned (per prespecified randomisation ratios within enrolment waves) according to a computer-generated randomisation scheme, stratified by age (<65 years and >= 65 years), to various intravenous or subcutaneous doses of casirivimab and imdevimab before, after, or at the same time as mRNA-1273 or to mRNA-1273 only. The doses of casirivimab and imdevimab were chosen to mimic various time intervals between receipt of 1200 mg of the mAb and the first dose of a primary series with mRNA-1273. The primary endpoint was vaccine-induced 50% inhibitory dilution neutralising antibody titres to SARS-CoV-2 spike protein, 56 days after the first vaccination. Secondary endpoints included vaccine-induced total antibodies to SARS-CoV-2 antigens and incidence of treatment-emergent adverse events. Exploratory endpoints included blood-derived T-cell and B-cell responses. The per-protocol set was used for the analysis of the primary endpoint and included all randomly assigned participants who received both doses ofthe vaccine and completed the injection or infusion of casirivimab and imdevimab per protocol, had no evidence of SARS-CoV-2 infection in the past or in the 56 days after the first dose of vaccine, and did not receive any intervention outside of the study that could alter the immune response. Safety was assessed in the safety analysis set, which included all randomly assigned participants who had received one or more doses of mRNA-1273 or any study drug, and analysed based on treatment received. The study is registered with ClinicalTrials.gov, NCT04852978, and is complete. Findings Between April 29, 2021, and Nov 21, 2022, 807 participants were assessed for eligibility and 295 were randomly assigned. 293 participants were included in the safety analysis set and 260 were included in the per-protocol set. All vaccinated participants developed neutralising antibodies to SARS-CoV-2, with median titres above the published protective threshold (100 IU/mL) against the SARS-CoV-2 D614G variant (considered a reference strain at the time the initial COVID-19 vaccines were developed). Titres were decreased up to 4-fold (median titres 280-450 IU/mL for casirivimab and imdevimab vs 1160 IU/mL for vaccine only on day 56) when casirivimab and imdevimab was given 85 days or less before vaccination (150-1200 mg intravenously) or co-administered subcutaneously (600 mg or 1200 mg) with vaccination. Minimal reduction in neutralisation titres was observed in the 48 mg and 12 mg intravenous groups, corresponding to receipt of casirivimab and imdevimab 113 days and 169 days, respectively, before vaccination, and when administering the vaccine 6 days before the mAb. Across all groups, mAbs had a minimal effect on vaccine- induced total antibodies and T-cell responses to the spike protein. Casirivimab and imdevimab plus mRNA-1273 was generally well tolerated; a slight increase in treatment-emergent adverse events was observed in the casirivimab and imdevimab plus vaccine groups versus the vaccine-only group. Interpretation Casirivimab and imdevimab administration before or at the time of COVID-19 vaccination reduced the elicitation of SARS-CoV-2 neutralising antibodies, but minimal effect was observed when vaccination occurred before mAb administration. Although the clinical significance of this decrease in neutralisation is unclear, this evidence suggests that further investigation of potential interactions could be warranted before concurrent clinical use of mAbs and vaccines targeting the same viral proteins as their main modes of action for the prevention or treatment of infectious diseases. Funding Regeneron Pharmaceuticals and F Hoffmann-La Roche. Copyright (c) 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.

Passive administration of SARS-CoV-2 neutralizing monoclonal antibodies, such as the CAS+IMD (REGEN-COV®, Ronapreve, REGN-COV2) antibody cocktail, benefits viral load, mortality rate, and clinical course in COVID-19 patients. However, their impact on resolving pathogenic inflammatory response and host immunity is less understood. This study examined CAS+IMD’s interaction with host immunity using longitudinal plasma proteomics and high-dimensional flow cytometry data. Unbiased clustering identified unique immunophenotypes linked to acute inflammation and disease resolution. Compared to the placebo group, CAS+IMD accelerated the shift from an acute inflammatory to a less inflammatory or “resolving” immunophenotype, marked by reduced tissue injury, lower proinflammatory markers, and restored lymphocyte/monocyte balance, regardless of baseline serostatus. Additionally, CAS+IMD did not impair the magnitude or quality of host T cell immunity against the SARS-CoV-2 spike protein. These findings suggest that SARS-CoV-2 neutralizing antibodies can rapidly resolve inflammatory responses, reducing the need for systemic steroids, without compromising cellular antiviral immunity. Supported Regeneron Pharmaceuticals and Department of Health and human service under OT number: HHSO100201700020C. Translational and Interventional Immunology (TI)

Biologics targeting interleukin-4 receptor subunit α (IL-4Rα) and interleukin-33 (IL-33) have demonstrated clinical efficacy in asthma, highlighting the importance of IL-4, IL-13, and IL-33 in respiratory diseases. Despite this, few studies have linked preclinical models to human diseases or evaluated disease biology in clinical trials. To address these gaps, we evaluated transcriptional, cellular, and pathophysiological processes driven by IL-4/IL-13 and IL-33 using human innate cells in vitro, a mouse model of airway inflammation, and a bronchial allergen challenge (BAC) in house dust mite (HDM)-sensitized individuals with mild asthma. Our findings in mice revealed that the prophylactic blockade of IL-4/IL-13, but not IL-33, prevented the initiation of HDM-induced type 2 inflammation, whereas blocking IL-4Rα or IL-33 during peak inflammation ameliorated airway inflammation and remodeling. Each pathway had unique and overlapping effects on airway inflammation and remodeling, with combination blockade showing no additional benefit. Initiating either monotherapy during severe, mixed inflammation resulted in partial efficacy, whereas a combination of these two treatments led to a substantial reduction in airway inflammation and remodeling in sensitized mice. Some of these mechanistic observations translated to a human BAC model, where blocking IL-4Rα or IL-33 alone suppressed gene expression in sputum and circulating biomarkers. As observed in mice, combination treatment in individuals with allergic asthma did not provide additional benefit compared to monotherapy. Overall, these results provide insight into the differences in targeting IL-4Rα or IL-33 pathways in asthma independently or in combination.

Immune checkpoint inhibitors have shown limited success in breast cancer, the most common and deadly cancer in women worldwide. Novel immune therapies, such as CD3-engaging bispecific antibodies, have shown clinical promise in hematologic malignancies. However, developing CD3 bispecifics for solid tumors has been challenging due to the difficulty in identifying tumor-specific antigens. B7-H4 is proposed as an attractive tumor-associated antigen for breast cancer therapeutics with comprehensive coverage regardless of breast cancer molecular subtype. We designed a B7-H4-targeting CD3 bispecific molecule, PF-07260437, and demonstrated B7-H4-dependent pharmacology in vitro by directing cytotoxic T-cell killing to breast cancer cell lines. Treatment of cell line- and patient-derived xenograft in vivo models of human breast cancer with PF-07260437 induced substantial tumoricidal activity, often resulting in complete responses. Mechanistically, PF-07260437 increased T-cell number and activation, leading to efficient tumor killing. Additionally, combining PF-07260437 with standard of care (palbociclib plus fulvestrant) and a checkpoint inhibitor (anti-PD-1) showed combinatorial benefits in an immune-competent in vivo model. Clinically relevant noninvasive PET/CT imaging with a CD8-targeting tracer demonstrated PF-07260437-mediated increases in intratumoral CD8 T cells, highlighting the utility of CD8-PET technology to potentially assess biomarker changes in the clinic. Finally, the manageable toxicity profile of PF-07260437 was highlighted in an exploratory toxicology study in cynomolgus monkeys. These data support the clinical testing of PF-07260437 for treating B7-H4-expressing solid tumors, including breast cancer.

Background: Biologics targeting IL-33 or IL-4Rα pathways have shown clinical efficacy in asthma and chronic obstructive pulmonary disease (COPD), underscoring the significance of IL-4, IL-13, and IL-33 in respiratory diseases. However, there are limited studies that connect preclinical models to human disease and assess disease biology within clinical trials. Methods: To bridge these gaps, we investigated the transcriptional, cellular, and pathophysiological processes driven by IL-4/IL-13 and IL-33 in a mouse model of airway inflammation, and a Bronchial Allergen Challenge (BAC) in house dust mite (HDM)-sensitized individuals with mild asthma. Results: In the HDM-driven mouse model of asthma, we demonstrate that IL-4/IL-13, but not IL-33 signaling, is required for initiation of allergen-induced Type 2 (T2) inflammation. On the other hand, blockade of either IL-4Rα with dupilumab or IL-33 with itepekimab at the peak of T2 inflammation resulted in improvement of airway inflammation and remodeling in the murine model. Interestingly, each pathway had distinct and similar effects on pathways that contribute to inflammation and remodeling, while combination blockade did not show additional benefit on T2 inflammation and mirrored monotherapy arms. In contrast, initiating either monotherapy treatment during established severe, mixed inflammation resulted in partial efficacy, while combination of these two treatments led to a significant reduction of airway inflammation and remodeling, suggesting a treatment opportunity beyond classical T2 inflammation. Some of these mechanistic observations translated to a human BAC model wherein blockade of either IL-4Rα or IL-33 resulted in suppression of gene expression in induced sputum and circulating biomarkers. Of note, combination treatment in the context of allergic airway inflammation did not provide additional benefit compared to monotherapy. Conclusions: These findings highlight IL-33 and IL-4/IL-13 as key drivers of airway inflammation and remodeling, offering insights into the differential effects of targeting IL-4Rα or IL-33 pathways in asthma, either independently or in combination.

BACKGROUND:Determining individual responses to vaccination is critical for effective prevention of SARS-CoV-2 infection, particularly in populations at risk of vaccine failure. METHODS:In this prospective study, we collected serum specimens prior to the first and post-second and -third vaccinations to examine the quantity, quality, and durability of immune responses to SARS-CoV-2 vaccination in patients receiving various immune-modulating therapies. To determine rates of vaccine failure, we measured SARS-CoV-2 anti-spike protein immunoglobulin G and neutralisation titres. FINDINGS:We analysed post-vaccination serum samples from 293 potentially immunocompromised patients (10·2 % haematologic malignancies, 56·0 % solid tumours, 27·6 % neuroimmunological conditions, and 6·1 % other). Based on IgG titres, 22·4 % and 12·0 % of cases were deemed vaccine failures by serology within 6 months of the second and third COVID-19 vaccinations, respectively; these rates were 32·7 % and 13·9 %, respectively, based on neutralisation. Notably, 12·2 % of samples did not have functional neutralising antibodies despite positive serology (mismatched result) within 6 months of the second COVID-19 vaccine dose. The highest rate of vaccine failure occurred in patients receiving active B-cell depleting therapies (primarily haematological malignancies or neuroimmunological conditions); those receiving cytotoxic chemotherapy or immune checkpoint inhibitors (predominantly patients with solid tumours) were at the lowest risk for vaccine failure. INTERPRETATION:Among patients receiving potentially immunosuppressive therapies, individuals treated with B-cell depletion therapies have high risk for vaccine failure after COVID-19 vaccination, but the rate of failure declines significantly with subsequent doses. In these populations, positive serology tests alone may not signify a protective immune response. FUNDING:Supported by a grant from Regeneron Pharmaceuticals, Inc., and P54 CA260560.

Pediatric Inflammatory Bowel Disease (IBD) remains challenging to treat and difficult to prognosticate. Although multiple immune cell types coordinate pathology in both Crohn's disease (CD) and ulcerative colitis (UC), specifying which cell types and cell states portend better or worse response to major IBD treatment strategies, including anti-TNF therapies (the only FDA-approved therapy for pediatric IBD), remains challenging. Here, we present the results of the PREDICT study, which enrolled 79 treatment-naïve pediatric patients at the time of diagnostic endoscopy, enabling a comprehensive transcriptomic, histologic, and serologic analysis of 40 CD patients and 16 UC patients, as well as 23 patients with functional gastrointestinal disorders (FGID) who served as pediatric non-inflamed controls. Leveraging these data, we performed a comprehensive analysis of colonic immunology in each of these clinical conditions. Our results indicate that, within the complex landscape of immune pathology in pediatric CD and UC, there is a coordinated shift across the TH1-to-TH17 immune activation continuum among T cells that is pertinent to anti-TNF response. For CD, this shift defines partial response to anti-TNF treatment. For UC, the landscape is more complex, with both TH17 and TFH biology defining disease, and pre-treatment TH17 biology contributing to anti-TNF treatment resistance. Related to this, polyreactive TCR phenotypes within UC TFH cells are correlated with both germinal center activity and the frequency of IgG1 plasma cells, yet opposed to the TH17 signatures associated with anti-TNF nonresponse. The elucidation of these distinct mechanisms of T cell-dependent disease pathology, treatment response, and TCR polyreactivity suggests a model in which sustained TH17 signaling in CD and baseline TH17 signaling in UC are associated with disease pathogenesis, forming a basis for a generalized understanding of IBD pathogenesis and underscoring the need for endotype-specific approaches to IBD therapy.

Background Passive administration of SARS-CoV-2 neutralizing monoclonal antibodies (mAbs), such as CAS + IMD (Casirivimab + Imdevimab) antibody cocktail demonstrated beneficial effects on clinical outcomes in hospitalized patients with COVID-19 who were seronegative at baseline and outpatients. However, little is known about their impact on the host immunophenotypes. Methods We conducted an immunoprofiling study in 46 patients from a single site of a multi-site trial of CAS + IMD in hospitalized patients. We collected longitudinal samples during October 2020 ∼ April 2021, prior to the emergence of the Delta and Omicron variants and the use of COVID-19 vaccines. All collected samples were analyzed without exclusion and post-hoc statistical analysis was performed. We examined the dynamic interplay of CAS + IMD with host immunity applying dimensional reduction approach on plasma proteomics and high dimensional flow cytometry data. Findings Using an unbiased clustering method, we identified unique immunophenotypes associated with acute inflammation and disease resolution. Compared to placebo group, administration of CAS + IMD accelerated the transition from an acute inflammatory immunophenotype, to a less inflammatory or “resolving” immunophenotype, as characterized by reduced tissue injury, proinflammatory markers and restored lymphocyte/monocyte imbalance independent of baseline serostatus. Moreover, CAS + IMD did not impair the magnitude or the quality of host T cell immunity against SARS-CoV-2 spike protein. Interpretation Our results identified immunophenotypic changes indicative of a possible SARS-CoV-2 neutralizing antibodies-induced anti-inflammatory effect, without an evident impairment of cellular antiviral immunity, suggesting that further studies of Mabs effects on SAS-CoV-2 or other viral mediated inflammation are warranted. Funding Regeneron Pharmaceuticals Inc and federal funds from the Department of Health and Human Services; Administration for Strategic Preparedness and Response; Biomedical Advanced Research and Development Authority, under OT number: HHSO100201700020C.

BACKGROUND:Peanut allergy is a potentially life-threatening food allergy in children. This study explored whether dupilumab, a human monoclonal immunoglobulin (Ig)G4 antibody that blocks the activity of interleukin (IL)-4/IL-13, improved safety and desensitization to peanut exposure in children with peanut allergy. METHODS:A Phase II, 24-week, multicenter, single-arm, open-label, proof-of-concept study was conducted in the USA and Canada (NCT03793608). Children/adolescents with peanut allergy received subcutaneous dupilumab 300 mg (≥ 60 kg) or 200 mg (≥ 20 to < 60 kg) every 2 weeks. The primary endpoint was the proportion of participants who passed a double-blind placebo-controlled food challenge (DBPCFC) with ≥ 444 mg (cumulative) of peanut protein at week 24. Secondary endpoints included safety measures (Consortium of Food Allergy Research grading system) and change from baseline in peanut-specific (ps)-IgG4, total IgE, and ps-IgE. RESULTS:Twenty-four participants enrolled and received dupilumab: 75.0% were male, 79.2% were white, mean (standard deviation) age was 11.7 (3.3) years. Most (95.8%) participants had not received allergen immunotherapy. Two participants (8.3%) achieved the primary endpoint and passed the DBPCFC at week 24. Fifteen participants (62.5%) reported 66 treatment-emergent adverse events, all being mild or in moderate intensity. At the week 24 DBPCFC, 8 participants (33.3%) had a grade 2 allergic reaction (no grade 3 or above); 10 (41.7%) used adrenaline as a rescue medication. Dupilumab treatment resulted in a median reduction of total and ps-IgE of -54% and -49%, respectively, and a 0% change in ps-IgG4. CONCLUSIONS:Dupilumab monotherapy treatment for 24 weeks did not improve desensitization to peanut exposure after food challenge.

BACKGROUND:Peanut allergy is a common, life-threatening food allergy in children. We evaluated whether dupilumab, which blocks the activity of interleukin (IL)-4/IL-13, enhances the efficacy of oral immunotherapy (OIT) AR101 in pediatric patients with peanut allergy. METHODS:A Phase II, multicenter, randomized, double-blind study was conducted in the USA (NCT03682770) in pediatric patients (6-≤ 17 years old) with confirmed peanut allergy. Patients were randomized 2:1 to receive dupilumab + OIT or placebo + OIT during a 28-40-week up-dosing period. Patients in the dupilumab + OIT group were re-randomized 1:1 and received dupilumab + OIT or placebo + OIT during 24-week OIT maintenance, undergoing a 2044 mg (cumulative) of peanut protein double-blind, placebo-controlled food challenge (DBPCFC) following up-dosing, maintenance, and at 12-week post-treatment follow-up. RESULTS:The study enrolled 148 patients, 123 of whom were included in the modified full analysis set, with a mean age of 11.1 years. Dupilumab + OIT treatment (n = 84) led to a 20.2% increase (p < 0.05) in the number of patients who passed a DBPCFC to 2044 mg (cumulative) of peanut protein following the up-dosing period versus placebo (OIT alone, n = 39). Following the OIT maintenance period, continuous dupilumab treatment improved the number of patients who passed a DBPCFC to 2044 mg (cumulative) of peanut protein versus patients continuously on OIT alone (16.6% difference [95% CI -9.7, 42.8], p = 0.2123). Safety was consistent with known dupilumab safety profile. CONCLUSIONS:Dupilumab provided a modest increase efficacy of OIT in children and adolescents with peanut allergy, though it did not provide protection against OIT-related anaphylaxis. TRIAL REGISTRATION:ClinicalTrials.gov identifier: NCT03793608.

The safety of casirivimab + imdevimab (CAS + IMD) (anti-severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] monoclonal antibodies [mAbs]) in pediatric outpatients with coronavirus disease 2019 (COVID-19) was evaluated in a randomized phase 1/2/3 trial. Consistent with adults, CAS + IMD was generally well tolerated with low drug-induced immunogenicity rates. The findings support the development of next-generation anti-SARS-CoV-2 mAbs for at-risk pediatric patients. Casirivimab and imdevimab (CAS + IMD) treatment was well-tolerated in pediatric outpatients with >= 1 risk factor for severe coronavirus disease 2019 (COVID-19), with similar safety and pharmacokinetic profiles as observed in adults. CAS + IMD was associated with low rates of COVID-19-related medically attended visits.

Objective Pregnant women with COVID-19 are at elevated risk for severe outcomes, but clinical data on management of these patients are limited. Monoclonal antibodies, such as casirivimab plus imdevimab (CAS+IMD), have proven effective in treating non-pregnant adults with COVID-19, prompting further evaluation in pregnant women.Methods A phase 3 portion of an adaptive, multicentre, randomised, double-blind, placebo-controlled trial evaluated the safety, clinical outcomes, pharmacokinetics and immunogenicity of CAS+IMD (1200 mg or 2400 mg) in the treatment of pregnant outpatients with COVID-19 (NCT04425629). Participants were enrolled between December 2020 and November 2021, prior to the emergence of Omicron-lineage variants against which CAS+IMD is not active. Safety was evaluated in randomised participants who received study drug (n=80); clinical outcomes were evaluated in all randomised participants (n=82). Only two pregnant participants received placebo, limiting conclusions regarding treatment effect. Infants born to pregnant participants were followed for developmental outcomes ≤1 year of age.Results In pregnant participants, CAS+IMD was well tolerated, with no grade ≥2 hypersensitivity or infusion-related reactions reported. There were no participant deaths, and only one COVID-19–related medically attended visit. Although two pregnancies (3%) reported issues in the fetus/neonate, they were confounded by maternal history or considered to be due to an alternate aetiology. No adverse developmental outcomes in infants ≤1 year of age were considered related to in utero exposure to the study drug. CAS+IMD 1200 mg and 2400 mg rapidly and similarly reduced viral loads, with a dose-proportional increase in concentrations of CAS+IMD in serum. Pharmacokinetics were consistent with that reported in the general population. Immunogenicity incidence was low.Conclusion CAS+IMD treatment of pregnant outpatients with COVID-19 showed similar safety, clinical outcomes and pharmacokinetic profiles to that observed in non-pregnant adults. There was no evidence of an impact on developmental outcomes in infants ≤1 year of age.Trial registration number NCT04425629.

Increased use of antiviral monoclonal antibodies (mAbs) for treatment and prophylaxis necessitates better understanding of their impact on endogenous immunity to vaccines and viruses. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic presented an opportunity to study immunity in individuals who received antiviral mAbs and were subsequently immunized with vaccines encoding the mAb-targeted viral spike antigen. Here, we describe the impact of administration of an antibody combination, casirivimab plus imdevimab (CAS+IMD), on immune responses to subsequent SARS-CoV-2 vaccination in humans, nonhuman primates, and mice. The presence of CAS+IMD at the time of vaccination led to a specific diminishment of vaccine-elicited pseudovirus neutralizing antibody titers without overall dampening of spike protein-directed immune responses, including antibody, B cell, and T cell responses. The impact on pseudovirus neutralizing titers extended to other therapeutic anti-spike protein antibodies when used as either monotherapy or combination therapy. The specific reduction in pseudovirus neutralizing titers was the result of epitope masking, a phenomenon where specific epitopes are bound by high-affinity antibodies and blocked from B cell recognition. Encouragingly, this reduction in pseudovirus neutralizing titers was reversible with additional booster vaccination. Moreover, by assessing the antiviral immune response in SARS-CoV-2-infected individuals treated therapeutically with CAS+IMD, we demonstrated alteration of antiviral humoral immunity in those who had received mAb therapy, but only in those individuals who had yet to start mounting their natural immune response at the time of mAb treatment. Together, these data demonstrate that antiviral mAbs can alter endogenous humoral immunity during vaccination or infection.

PDF file - 116K, Structure of the MCT1 inhibitors AR-C122982 (SR13800) and AR-C155858 (SR13801). Cell cycle analysis, viability, clonogenecity and lactate transport in the indicated cells treated with SR13800. Proliferation of MCF7 cells overexpressing MCT1 or MCT4.

Severe, protracted symptoms are associated with poor outcomes in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In a placebo-controlled study of casirivimab and imdevimab (CAS + IMD) in persons at high risk of severe coronavirus disease 2019 (COVID-19; n = 3816), evolution of individual symptoms was assessed for resolution patterns across risk factors, and baseline SARS-CoV-2-specific antibody responses against S1 and N domains. CAS + IMD versus placebo provided statistically significant resolution for 17/23 symptoms, with greater response linked to absence of endogenous anti–SARS-CoV-2 immunoglobulin (Ig)G, IgA, or specific neutralizing antibodies at baseline, or high baseline viral load. Resolution of five key symptoms (onset days 3–5)—dyspnea, cough, feeling feverish, fatigue, and loss of appetite—independently correlated with reduced hospitalization and death (hazard ratio range: 0.31–0.56; P < 0.001–0.043), and was more rapid in CAS + IMD-treated patients lacking robust early antibody responses. Those who seroconverted late still benefited from treatment. Thus, highly neutralizing COVID-19-specific antibodies provided by CAS + IMD treatment accelerated key symptom resolution associated with hospitalization and death in those at high risk for severe disease as well as in those lacking early, endogenous neutralizing antibody responses.

Supplemental Figure S1. Concentration versus time profiles of ipilimumab and nivolumab following four weekly intravenous dose administrations of 15 mg/kg or 20 mg/kg, respectively. Supplementary Figure S2. Hematoxylin and eosin stained sections of tissues from control and monkeys dosed with ipilimumab and nivolumab. Supplementary Figure S3. Quantification of mononuclear cell infiltrates from IHC images of heart sections.

Abstract Background Individuals who are immunocompromised (IC) are at high risk for severe coronavirus disease 2019 (COVID-19). Methods Post hoc analyses of a double-blind trial conducted prior to Omicron (June 2020–April 2021), in hospitalized patients with COVID-19 assessed viral load, clinical outcomes, and safety of casirivimab plus imdevimab (CAS + IMD) versus placebo in IC versus overall study patients. Results Ninety-nine of 1940 (5.1%) patients were IC. IC versus overall patients were more frequently seronegative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies (68.7% vs 41.2%) and had higher median baseline viral loads (7.21 vs 6.32 log10 copies/mL). On placebo, IC versus overall patients had slower viral load declines. CAS + IMD reduced viral load in IC and overall patients; least-squares mean difference versus placebo in time-weighted average change from baseline viral load at day 7 was −0.69 (95% confidence interval [CI], −1.25 to −.14) log10 copies/mL for IC patients and −0.31 (95% CI, −.42 to −.20) log10 copies/mL for overall patients. For IC patients, the cumulative incidence of death or mechanical ventilation at day 29 was lower with CAS + IMD (11.0%) versus placebo (17.2%), consistent with overall patients (15.7% CAS + IMD vs 18.3% placebo). IC and overall patients receiving CAS + IMD exhibited similar rates of treatment-emergent adverse events (30.4% and 26.6%, respectively), grade ≥2 hypersensitivity or infusion-related reactions (1.4% and 2.5%), and deaths (8.7% and 12.2%). Conclusions IC patients were more likely to exhibit high viral loads and be seronegative at baseline. For susceptible SARS-CoV-2 variants, CAS + IMD reduced viral load and resulted in fewer death or mechanical ventilation events in IC and overall study patients. There were no new safety findings among IC patients. Clinical Trials Registration. NCT04426695.