Combination Of Monoclonal Antibodies Research Articles

Pre-exposure prophylaxis with tixagevimab and cilgavimab (Evusheld) for COVID-19 among 1112 severely immunocompromised patients

ObjectiveImmunocompromised patients have an increased risk of a severe form of COVID-19. The clinical efficacy of the tixagevimab/cilgavimab monoclonal antibody combination as pre-exposure prophylaxis against BA.1 and BA.2 SARS-CoV-2 Omicron sublineages is unknown. We aimed to describe the incidence and outcomes of COVID-19 among immunocompromised patients receiving tixagevimab/cilgavimab as preexposure prophylaxis during the Omicron wave in France. MethodsThis was an observational multicentre cohort study of immunocompromised patients receiving tixagevimab/cilgavimab as preexposure prophylaxis between December 28, 2021 and March 31, 2022. Patients received tixagevimab/cilgavimab 150/150 mg intramuscularly if they had impaired vaccine response and a high risk of severe form of COVID-19. ResultsTixagevimab/cilgavimab was administered to 1112 immunocompromised patients. After a median (range) follow-up of 63 (49–73) days, COVID-19 was confirmed in 49/1112 (4.4%) ≥5 days after treatment. During the study period, mean weekly incidence rate was 1669 in 100 000 inhabitants in Ile-de-France and 530 in 100 000 among patients who received tixagevimab/cilgavimab prophylaxis. Among infected patients, 43/49 (88%) had a mild-to-moderate form and 6/49 (12%) had a moderate-to-severe form of COVID-19. Patients with moderate-to-severe illnesses were less likely to have received early therapies than patients with mild forms (53.5% vs. 16.7% respectively) and 2/49 (4%) patients died from COVID-19. DiscussionOur study reported a low rate of infections and severe illnesses among immunocompromised patients treated with tixagevimab/cilgavimab. A global preventive strategy including vaccines, preexposure prophylaxis with monoclonal antibodies, and early therapies might be effective to prevent severe forms of COVID-19 among severely immunocompromised patients.

Characterization of SARS-CoV-2 Escape Mutants to a Pair of Neutralizing Antibodies Targeting the RBD and the NTD.

Mutations in the spike protein of SARS-CoV-2 can lead to evasion from neutralizing antibodies and affect the efficacy of passive and active immunization strategies. Immunization of mice harboring an entire set of human immunoglobulin variable region gene segments allowed to identify nine neutralizing monoclonal antibodies, which either belong to a cluster of clonally related RBD or NTD binding antibodies. To better understand the genetic barrier to emergence of SARS-CoV-2 variants resistant to these antibodies, escape mutants were selected in cell culture to one antibody from each cluster and a combination of the two antibodies. Three independently derived escape mutants to the RBD antibody harbored mutations in the RBD at the position T478 or S477. These mutations impaired the binding of the RBD antibodies to the spike protein and conferred resistance in a pseudotype neutralization assay. Although the binding of the NTD cluster antibodies were not affected by the RBD mutations, the RBD mutations also reduced the neutralization efficacy of the NTD cluster antibodies. The mutations found in the escape variants to the NTD antibody conferred resistance to the NTD, but not to the RBD cluster antibodies. A variant resistant to both antibodies was more difficult to select and only emerged after longer passages and higher inoculation volumes. VOC carrying the same mutations as the ones identified in the escape variants were also resistant to neutralization. This study further underlines the rapid emergence of escape mutants to neutralizing monoclonal antibodies in cell culture and indicates the need for thorough investigation of escape mutations to select the most potent combination of monoclonal antibodies for clinical use.

Engineered bispecific antibodies targeting the interleukin-6 and -8 receptors potently inhibit cancer cell migration and tumor metastasis

Simultaneous inhibition of interleukin-6 (IL-6) and interleukin-8 (IL-8) signaling diminishes cancer cell migration, and combination therapy has recently been shown to synergistically reduce metastatic burden in a preclinical model of triple-negative breast cancer. Here, we have engineered two novel bispecific antibodies that target the IL-6 and IL-8 receptors to concurrently block the signaling activity of both ligands. We demonstrate that a first-in-class bispecific antibody design has promising therapeutic potential, with enhanced selectivity and potency compared with monoclonal antibody and small-molecule drug combinations in both cellular and animal models of metastatic triple-negative breast cancer. Mechanistic characterization revealed that our engineered bispecific antibodies have no impact on cell viability, but profoundly reduce the migratory potential of cancer cells; hence they constitute a true anti-metastatic treatment. Moreover, we demonstrate that our antibodies can be readily combined with standard-of-care anti-proliferative drugs to develop effective anti-cancer regimens. Collectively, our work establishes an innovative metastasis-focused direction for cancer drug development.

Correction to: Different Combinations of Monoclonal Antibodies and Polyclonal Antibodies in the Design of Neonatal Hypothyroidism Diagnostic Kit

Correction to: Different Combinations of Monoclonal Antibodies and Polyclonal Antibodies in the Design of Neonatal Hypothyroidism Diagnostic Kit

A bivalent SARS-CoV-2 monoclonal antibody combination does not affect the immunogenicity of a vector-based COVID-19 vaccine in macaques.

Human monoclonal antibodies (mAbs) that target the spike glycoprotein of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) offer a promising approach for the prevention and treatment of coronavirus disease 2019 (COVID-19). Given suboptimal global vaccination rates, waning immunity in vaccinated individuals, and the emergence of SARS-CoV-2 variants of concern, the use of mAbs for COVID-19 prevention may increase and may need to be administered together with vaccines in certain settings. However, it is unknown whether administration of mAbs will impact the immunogenicity of SARS-CoV-2 vaccines. Using an adenovirus vector-based SARS-CoV-2 vaccine, we show that simultaneous administration of the vaccine with SARS-CoV-2 mAbs does not diminish vaccine-induced humoral or cellular immunity in cynomolgus macaques. These results suggest that SARS-CoV-2 mAbs and viral vector-based SARS-CoV-2 vaccines can be administered together without loss of potency of either product. Additional studies will be required to evaluate co-administration of mAbs with other vaccine platforms.

Tixagevimab–cilgavimab for treatment of patients hospitalised with COVID-19: a randomised, double-blind, phase 3 trial

BackgroundTixagevimab–cilgavimab is a neutralising monoclonal antibody combination hypothesised to improve outcomes for patients hospitalised with COVID-19. We aimed to compare tixagevimab–cilgavimab versus placebo, in patients receiving remdesivir and other standard care.MethodsIn a randomised, double-blind, phase 3, placebo-controlled trial, adults with symptoms for up to 12 days and hospitalised for COVID-19 at 81 sites in the USA, Europe, Uganda, and Singapore were randomly assigned in a 1:1 ratio to receive intravenous tixagevimab 300 mg–cilgavimab 300 mg or placebo, in addition to remdesivir and other standard care. Patients were excluded if they had acute organ failure including receipt of invasive mechanical ventilation, extracorporeal membrane oxygenation, vasopressor therapy, mechanical circulatory support, or new renal replacement therapy. The study drug was prepared by an unmasked pharmacist; study participants, site study staff, investigators, and clinical providers were masked to study assignment. The primary outcome was time to sustained recovery up to day 90, defined as 14 consecutive days at home after hospital discharge, with co-primary analyses for the full cohort and for participants who were neutralising antibody-negative at baseline. Efficacy and safety analyses were done in the modified intention-to-treat population, defined as participants who received a complete or partial infusion of tixagevimab–cilgavimab or placebo. This study is registered with ClinicalTrials.gov, NCT04501978 and the participant follow-up is ongoing.FindingsFrom Feb 10 to Sept 30, 2021, 1455 patients were randomly assigned and 1417 in the primary modified intention-to-treat population were infused with tixagevimab–cilgavimab (n=710) or placebo (n=707). The estimated cumulative incidence of sustained recovery was 89% for tixagevimab–cilgavimab and 86% for placebo group participants at day 90 in the full cohort (recovery rate ratio [RRR] 1·08 [95% CI 0·97–1·20]; p=0·21). Results were similar in the seronegative subgroup (RRR 1·14 [0·97–1·34]; p=0·13). Mortality was lower in the tixagevimab–cilgavimab group (61 [9%]) versus placebo group (86 [12%]; hazard ratio [HR] 0·70 [95% CI 0·50–0·97]; p=0·032). The composite safety outcome occurred in 178 (25%) tixagevimab–cilgavimab and 212 (30%) placebo group participants (HR 0·83 [0·68–1·01]; p=0·059). Serious adverse events occurred in 34 (5%) participants in the tixagevimab–cilgavimab group and 38 (5%) in the placebo group.InterpretationAmong patients hospitalised with COVID-19 receiving remdesivir and other standard care, tixagevimab–cilgavimab did not improve the primary outcome of time to sustained recovery but was safe and mortality was lower.FundingUS National Institutes of Health (NIH) and Operation Warp Speed.

Efficacy and safety of a single dose of casirivimab and imdevimab for the prevention of COVID-19 over an 8-month period: a randomised, double-blind, placebo-controlled trial

BackgroundThere is an unmet need for COVID-19 prevention in patient populations who have not mounted or are not expected to mount an adequate immune response to complete COVID-19 vaccination. We previously reported that a single subcutaneous 1200 mg dose of the monoclonal antibody combination casirivimab and imdevimab (CAS + IMD) prevented symptomatic SARS-CoV-2 infections by 81·4% in generally healthy household contacts of SARS-CoV-2-infected individuals over a 1-month efficacy assessment period. Here we present additional results, including the 7-month follow-up period (months 2–8), providing additional insights about the potential for efficacy in pre-exposure prophylaxis settings.MethodsThis was a randomised, double-blind, placebo-controlled trial done in the USA, Romania, and Moldova in 2020–2021, before the emergence of omicron (B.1.1.529) and omicron-lineage variants. Uninfected and unvaccinated household contacts of infected individuals, judged by the investigator to be in good health, were randomly assigned (1:1) to receive 1200 mg CAS + IMD or placebo by subcutaneous injection according to a central randomisation scheme provided by an interactive web response system; randomisation was stratified per site by the test results of a local diagnostic assay for SARS-CoV-2 and age group at baseline. COVID-19 vaccines were prohibited before randomisation, but participants were allowed to receive COVID-19 vaccination during the follow-up period. Participants who developed COVID-19 symptoms during the follow-up period underwent RT-PCR testing. Prespecified endpoints included the proportion of previously uninfected and baseline-seronegative participants (seronegative-modified full analysis set) who had RT-PCR-confirmed COVID-19 in the follow-up period (post-hoc for the timepoints of months 2–5 and 6–8 only) and underwent seroconversion (ie, became seropositive, considered a proxy for any SARS-CoV-2 infections [symptomatic and asymptomatic]; prespecified up to day 57, post-hoc for all timepoints thereafter). We also assessed the incidence of treatment-emergent adverse events. This study is registered with ClinicalTrials.gov, NCT04452318.FindingsFrom July 13, 2020, to Oct 4, 2021, 2317 participants who were RT-PCR-negative for SARS-CoV-2 were randomly assigned, of whom 1683 (841 assigned to CAS + IMD and 842 assigned to placebo) were seronegative at baseline. During the entirety of the 8-month study, CAS + IMD reduced the risk of COVID-19 by 81·2% (nominal p<0·0001) versus placebo (prespecified analysis). During the 7-month follow-up period, protection was greatest during months 2–5, with a 100% relative risk reduction in COVID-19 (nominal p<0·0001; post-hoc analysis). Efficacy waned during months 6–8 (post-hoc analysis). Seroconversion occurred in 38 (4·5%) of 841 participants in the CAS + IMD group and in 181 (21·5%) of 842 in the placebo group during the 8-month study (79·0% relative risk reduction vs placebo; nominal p<0·0001). Six participants in the placebo group were hospitalised due to COVID-19 versus none who received CAS + IMD. Serious treatment-emergent adverse events (including COVID-19) were reported in 24 (1·7%) of 1439 participants receiving CAS + IMD and in 23 (1·6%) of 1428 receiving placebo. Five deaths were reported, none of which were due to COVID-19 or related to the study drugs.InterpretationCAS + IMD is not authorised in any US region as of Jan 24, 2022, because data show that CAS + IMD is not active against omicron-lineage variants. In this study, done before the emergence of omicron-lineage variants, a single subcutaneous 1200 mg dose of CAS + IMD protected against COVID-19 for up to 5 months of community exposure to susceptible strains of SARS-CoV-2 in the pre-exposure prophylaxis setting, in addition to the post-exposure prophylaxis setting that was previously shown.FundingRegeneron Pharmaceuticals, F Hoffmann-La Roche, US National Institute of Allergy and Infectious Diseases, US National Institutes of Health.

Efficiency of Monoclonal Antibodies Application against Covid-19

Despite the 20 years history of pathogenic coronavirus infection, methods of prevention and treatment of diseases caused by this infection were not developed yet. One of the reasons could be the features of pathogenesis and a quick spread of the pandemic which may have made researches more complicated. As an inflammatory process develops, a generalization of infection also develops. A cytokine secretion becomes rockets up, Interferon-γ (IFN-y), interleukin-1(IL-1), interleukin-6 (IL-6), interleukin-12 (IL-12), concentration increases. To put it in other words, the primary inflammatory reaction enters a new phase — the cytokine storm phase. In this regard, adequate therapy aimed at stopping the uncontrolled process induced not so much by viremia as by the inflammation associated with it becomes crucial. Therefore, the aim of our research was to study the impact of monoclonal antibodies, in particular the drug "Kazirivimab + Imdevimab" — a combination of recombinant monoclonal antibodies aimed against S-protein on the clinical course and laboratory data in patients with a new coronavirus infection – Covid-19.

P1450: AUTOLOGOUS STEM CELL TRANSPLANTATION INDUCES HIGHER LEVEL OF EXHAUSTED T-CELLS IN DLBCL PATIENTS BEFORE LEUKAPHERESIS FOR CAR-T CELL THERAPY.

Background: Chimeric antigen receptor T-cells (CAR-T) are an highly effective therapy in relapse/refractory DLBCL, PMBCL and ALL, but almost half of treated patients (pts) still relapse. CAR-T cells generated from T-lymphocytes (T-Ly) enriched for early lineage T cells has shown durable persistence and replicative potential both in animal and in vivo models, while CAR-T cells from “exhausted” T-Ly have been related with poorer response. In the prospective BioCART BS study, we assessed the T-cell repertoire before the Ly-apheresis in DLBCL patients for evaluating the impact of previous treatments and efficacy of CAR-T therapy. Aims: To evaluate T-cells repertoire before the Ly-apheresis in high risk DLBCL pts. Methods: Between April and December 2021, a total of 11 DLBCL pts underwent Ly-apheresis for CAR-T manufacturing. Since cryopreservation of the apheresed Ly is allowed for Tisa-cel, DLBCL pts with poor prognostic risk factor (refractory to first line of treatment; PET positivity before Autologous Stem Cell Transplantation [ASCT]; first complete response less than 12 months) were enrolled in an early/“pre-emptive” Ly-apheresis program, scheduling leukapheresis as soon as possible, with the aim to collect more “fit” Ly. Combinations of monoclonal antibodies directed against CD45RA, CCR7, CD3, CD4, and CD8 were used by Flow Cytometry to evaluate the following CD4+/CD8+ T-ly subsets: T-naïve (CD45RA+CCR7+); central memory (CM, CD45RA-CCR7+); effector memory (EM, CD45RA-CCR7-); terminally differentiated (TD; CD45RA+CCR7-). For evaluating CAR-T cells expansion, pts’ cells were tested with a specific biotinilated CD19 CAR reagent followed by incubation with an anti-biotin PE conjugated MoAb. The time points were: at day +1, +3, +7, +10, +14, +21 after CAR-T cells infusion, and then monthly until 1 year or at any time for relapse onset. All stained samples were acquired on a Canto II (BD Bioscience) flow cytometer and analyzed using DIVA software version 8.0.2. Continuous and categorical variables were compared using an unpaired T-test, Mann-Whitney U test, or Chi-square test, as appropriate. Results: Table 1 shows the main patients’ characteristics. 5 out of the 11 (45%) pts performed Ly-apheresis before ASCT. At the time of Ly-apheresis, no significative differences were observed between pts who previously underwent ASCT and those who did not, except for age. ASCT induced a more “exhausted” T-cells repertoire. Indeed, pts who previously underwent ASCT had lower CD4+/CD8+ ratio (p 0.04) (Fig 1C) as well as lower levels of CD4+ Naïve T cells, both in terms of absolute count (p 0.05) and as percentage of CD4+ T cells (p 0, 01), and lower prevalence of CD8+ Naïve T cells (p 0.03) (Fig 1A). Moreover they also presented higher prevalence of CD4+ EM T cells (p 0.01) and of CD4+ TD T-cells (p 0.05), as well as higher level of both CD8+ CM (p 0.03) and TD (p 0.05) T cells (Fig 1B). 3 out of the 6 pts who underwent ASCT before Ly-apheresis and 2 of the 5 who did not, sent Ly for manufacturing. To date, no differences were apparently observed on CAR-T cells expansion comparing the two groups, but the number of pts analyzed is too small to make any consideration (Fig 1D for pts with longer follow up). - Ly-apheresis PRE ASCT Ly-apheresis POST ASCT p value Number 5 6 Age 51 (29-60) 67 (57-70) 0.02 Disease status @Ly-apheresis 1 2 0.08 Refractory 0 3 Relapse 4 1 Partial response Image:Summary/Conclusion: ASCT before Ly-apheresis may result in a higher prevalence of “exhausted” T-cells. In DLBCL pts primary refractory or at high risk of relapse after second line of treatment, timely pre-ASCT Ly-apheresis would be considered.

Abstract 2874: The tetravalent structure of FS118, a bispecific antibody targeting LAG-3 and PD-L1, is required for its novel mechanism of LAG-3 shedding

Abstract FS118 is a tetravalent bispecific antibody targeting LAG-3 and PD-L1 that can overcome immune suppressive signals with greater preclinical activity than a combination of monoclonal antibodies. In vivo, FS118 downregulates LAG-3 on tumor-infiltrating lymphocytes (TILs) and increases soluble LAG-3 (sLAG-3) in the serum of mice. In a Phase 1 trial, FS118 demonstrated a dose-dependent increase in sLAG-3 in the serum of patients with advanced malignancies. Here, we demonstrate that the tetravalent structure of FS118 is required to mediate this novel LAG-3 shedding mechanism. Human ex vivo assays were performed by co-culturing expanded CD4+ T cells with iDCs in the presence of Staphylococcal enterotoxin B and FS118, or controls. sLAG-3 was measured by ECLIA. The binding valency of FS118 was determined using chemically-crosslinked mass spectrometry mapping (XL/MS). Variants of FS118 and FS118 surrogate molecules were generated with differing valency for LAG-3 and PD-L1. MC38 tumor-bearing C57BL/6 mice were dosed once interperitoneally with FS118 surrogate or valency variants. TILs were analyzed by flow cytometry, and sLAG-3 was measured in the serum by ECLIA. In patients receiving FS118 treatment, a dose-dependent increase in sLAG-3 was detected in the blood. In an ex vivo human T cell assay, the FS118-mediated increase in sLAG-3 was greater than with the combination of the individual bispecific components. sLAG-3 increase by FS118 was mediated by ADAM10 and ADAM17. FS118 demonstrated tetravalent binding to its target antigens using XL/MS. All four binding sites simultaneously bound to target antigens, with preferential binding to PD-L1 in the presence of equal amounts of both LAG-3 and PD-L1. Variants of FS118 with reduced binding valency for target antigens mediated lower levels of LAG-3 release than tetravalent FS118. Compared to FS118, monovalent PD-L1 binding reduced sLAG-3 release and importantly, a variant of FS118 with monovalent LAG-3 binding generated the lowest level of sLAG-3. Data will be presented showing the role of binding valency on LAG-3 downregulation by TILs and T cell activation in ex vivo murine samples. FS118 is tetravalent and can bind to two LAG-3 and two PD-L1 molecules simultaneously. Bivalent LAG-3 and PD-L1 binding is required for enhanced shedding of cell surface LAG-3 in vitro. Removing LAG-3 from the surface of exhausted TILs is a novel mechanism attributed to the tetravalent structure of FS118, which may be important to overcome compensatory upregulation of LAG-3 induced by blockade of PD-L1 in patients. Citation Format: Claire S. Reader, Wenjia Liao, Beatrice J. Potter-Landau, Christel Séguy Veyssier, Martyn C. Rhoades, Claire J. Seal, Michelle Morrow, Neil Brewis. The tetravalent structure of FS118, a bispecific antibody targeting LAG-3 and PD-L1, is required for its novel mechanism of LAG-3 shedding [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2874.

Abstract 3428: NI-2901, a CD47xPD-L1 bispecific antibody for dual immune checkpoint blockade with fine-tuned affinity to reduce erythrocyte binding and improve biodistribution

Abstract Blocking the CD47/SIRPα checkpoint has recently emerged as an effective approach to mobilize the myeloid cell compartment and to improve antitumor responses in the clinic. Preclinical models have demonstrated the synergistic benefit of combined CD47/SIRPα and PD-1/PD-L1 blockade. Combinations of monoclonal antibodies (mAbs) targeting these two checkpoint pathways are being explored in the clinic. CD47xPD-L1 bispecific antibodies (bsAbs) stand as an attractive alternative to mAb combinations, even more so as they provide a potential solution to improve the pharmacokinetic profile and safety issues faced by CD47 targeted-mAbs and SIRPα-Fc fusion proteins. CD47xPD-L1 bsAbs are expected to preferentially inhibit CD47 on PD-L1 expressing cells, displaying improved safety and pharmacokinetics, but also superior tumor microenvironment targeting capabilities. With the objective of finding the optimal CD47xPD-L1 bsAb, an array of bispecific antibodies (bsAbs) was generated associating a high affinity PD-L1 arm to CD47 arms with varying affinities. The CD47xPD-L1 bsAbs of human IgG4 isotype were generated using our fully human κλ body antibody platform. The candidate molecules were screened for binding and receptor-blocking activity and tested for their capacity to enhance T-cell activation and phagocytosis of tumor cells in the presence of anti-HER-2 mAb, trastuzumab. Selected bsAbs were also evaluated in a xenograft mouse model. The CD47xPD-L1 bsAbs demonstrated an effective blockade of the PD-1/PD-L1 interaction, being able to induce T-cell activation in vitro similar to the anti-PD-L1 clinical benchmark, atezolizumab. Consistent with their CD47 affinities, the bsAbs showed varying levels of CD47 blockade on PD-L1-negative cells and a low binding capacity to red blood cells. Nonetheless, trastuzumab-mediated phagocytosis of tumor cells expressing low levels of PD-L1 could be significantly enhanced by these bsAbs, confirming the PD-L1-independent activity of the CD47 blocking arms. The latter findings were corroborated in vivo using PD-L1-negative Raji cells in a xenograft mouse model. Selected bsAbs will be now tested for tolerability and pharmacokinetic profiles in human-CD47/human-SIRPα transgenic mice. Lead candidate(s) will be evaluated further for PK and safety attributes in non-human primates in early Q1, 2022. Citation Format: Xavier Chauchet, Sébastien Calloud, Margaux Legrand, Laura Cons, Laurence Chatel, Pauline Lloveras, Coline Burnet-Merlin, Louis Hellequin, Nicolas Bosson, Pauline Malinge, Nicolas Pleche, Jérémie Bourguignon, Guillemette Pontini, Christophe Guillamo, Ulla Ravn, Valéry Moine, Bruno Daubeuf, Yves Poitevin, Giovanni Magistrelli, Limin Shang, Walter Ferlin, Krzysztof Masternak. NI-2901, a CD47xPD-L1 bispecific antibody for dual immune checkpoint blockade with fine-tuned affinity to reduce erythrocyte binding and improve biodistribution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3428.

Abstract 3429: NI-2601, an Fc-active CD47xPD-L1 bispecific antibody that selectively targets CD47 on PD-L1-positive tumors

Abstract PD-1/PD-L1 blockade has improved survival across many types of cancer, but only in a minority of patients. Co-targeting PD-1/PD-L1 and the CD47/SIRPα myeloid checkpoint with monoclonal antibody (mAb) combinations showed increased antitumor responses in preclinical studies. However, CD47 mAbs are hindered by ubiquitous CD47 expression leading to rapid target-mediated clearance and safety concerns, including anemia and thrombocytopenia. Consequently, dual-targeting CD47xPD-L1 bispecific antibodies (bsAbs) enabling selective inhibition of CD47 on PD-L1-positive tumors offer an alternative approach. A fully human bsAb pairing a high affinity PD-L1 arm to a low affinity CD47 arm was generated using the κλ-body platform. The latter is also used in our CD47xCD19 bispecific antibody NI-1701/TG-1801, currently in phase I clinical trials (NCT03804996, NCT04806035). The resulting CD47xPD-L1 bsAb of human IgG1 isotype (NI-2601) was evaluated in various binding and receptor-blocking assays, and then tested for its capacity to enhance T-cell activation in vitro and induce Fc-mediated killing of tumor cells through phagocytosis (ADCP) and antibody-dependent cell cytotoxicity (ADCC). A surrogate bsAb was also evaluated in vivo in a syngeneic mouse model. NI-2601 demonstrated effective blockade of PD-1/PD-L1 interaction, and T-cell activation in vitro, similar to the anti-PD-L1 clinical benchmarks atezolizumab and avelumab. Consistent with its low-affinity CD47 arm, the bsAb did not bind to red blood cells (RBC) and CD47 blockade was driven by PD-L1 co-engagement. Using a panel of tumor cell lines, expressing various PD-L1 levels, NI-2601 showed superior activity in ADCP and ADCC as compared to the anti-PD-L1 IgG1 mAb, avelumab. The anti-tumor activity of this approach using surrogate CD47xPD-L1 bsAb was confirmed in a syngeneic MC38 colon carcinoma model. Thus, NI-2601 is able to harness Fc-effector function to eliminate PD-L1-positive tumor cells while sparing PD-L1-negative cells, such as RBC or platelets. Pharmacokinetic and tolerability studies in non-human primate are planned for 2022. Citation Format: Xavier Chauchet, Nicolas Bosson, Margaux Legrand, Laura Cons, Sébastien Calloud, Alizée Viandier, Françoise Richard, Pauline Malinge, Tereza Bautzova, Jérémie Bourguignon, Guillemette Pontini, Elise Penarrieta, Mengzhu Sun, Ulla Ravn, Valéry Moine, Giovanni Magistrelli, Yves Poitevin, Stéphanie Hugues, Limin Shang, Walter Ferlin, Krzysztof Masternak. NI-2601, an Fc-active CD47xPD-L1 bispecific antibody that selectively targets CD47 on PD-L1-positive tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3429.

Induction of high affinity monoclonal antibodies against SARS-CoV-2 variant infection using a DNA prime-protein boost strategy

BackgroundCalls for the coronavirus to be treated as an endemic illness, such as the flu, are increasing. After achieving high coverage of COVID-19 vaccination, therapeutic drugs have become important for future SARS-CoV-2 variant outbreaks. Although many monoclonal antibodies have been approved for emergency use as treatments for SARS-CoV-2 infection, some monoclonal antibodies are not authorized for variant treatment. Broad-spectrum monoclonal antibodies are unmet medical needs.MethodsWe used a DNA prime-protein boost approach to generate high-quality monoclonal antibodies. A standard ELISA was employed for the primary screen, and spike protein-human angiotensin-converting enzyme 2 blocking assays were used for the secondary screen. The top 5 blocking clones were selected for further characterization, including binding ability, neutralization potency, and epitope mapping. The therapeutic effects of the best monoclonal antibody against SARS-CoV-2 infection were evaluated in a hamster infection model.ResultsSeveral monoclonal antibodies were selected that neutralize different SARS-CoV-2 variants of concern (VOCs). These VOCs include Alpha, Beta, Gamma, Delta, Kappa and Lambda variants. The high neutralizing antibody titers against the Beta variant would be important to treat Beta-like variants. Among these monoclonal antibodies, mAb-S5 displays the best potency in terms of binding affinity and neutralizing capacity. Importantly, mAb-S5 protects animals from SARS-CoV-2 challenge, including the Wuhan strain, D614G, Alpha and Delta variants, although mAb-S5 exhibits decreased neutralization potency against the Delta variant. Furthermore, the identified neutralizing epitopes of monoclonal antibodies are all located in the receptor-binding domain (RBD) of the spike protein but in different regions.ConclusionsOur approach generates high-potency monoclonal antibodies against a broad spectrum of VOCs. Multiple monoclonal antibody combinations may be the best strategy to treat future SARS-CoV-2 variant outbreaks.

Tixagevimab and Cilgavimab: Can we see More Recommendations for Monoclonal Antibodies Beyond COVID-19 Vaccination.

Nearly 3 years after its detection, the coronavirus disease 2019 (COVID-19) which is caused by severe acute respiratory syndrome CoV-2, is still a life-threatening global pandemic that has contributed to a high progression and mortality rate across the globe. This imposes the need for scientific research efforts in order to hold intense interest directed towards such exploration, for the development and optimization of different interventions to the COVID-19 infection. This commentary summarizes the potential clinical benefits for the recently authorized immunotherapy combination of Tixagevimab and Cilgavimab monoclonal antibodies for the prevention and treatment of COVID-19.

Dual-detection approach for a charge variant analysis of monoclonal antibody combination products using imaged capillary isoelectric focusing.

The clinical benefits of treatments with a combination of two or more therapeutic monoclonal antibodies (mAbs) have emerged in recent years. Imaged capillary isoelectric focusing is a frequently used technology in the biopharmaceutical industry for charge variant analysis of protein therapeutics. However, with the wide concentration ranges of combination products, one component may fall within the linear detection range, whereas the other does not. Here, we report a novel methodology to explore charge variants of mAb mixtures using multiple detection techniques simultaneously. We use ultraviolet absorbance to monitor the charge variants of the high-concentration component and native fluorescence (FL) to monitor the variants of the low-concentration one. Charge variants of mixtures that span 40-fold in ratio differences can be accurately quantified with this approach. In contrast to the conventional methods, it is not necessary to prepare and analyze two samples at different concentrations and combine the results for combination product testing. Additionally, the use of FL detection enables the charge variant analysis of highly potent/low abundant mAbs in a mixture. This methodology is more quality-control friendly and efficient for the charge variant analysis of combination products with wide ratios.

Efficacy and safety of intramuscular administration of tixagevimab–cilgavimab for early outpatient treatment of COVID-19 (TACKLE): a phase 3, randomised, double-blind, placebo-controlled trial

BackgroundEarly intramuscular administration of SARS-CoV-2-neutralising monoclonal antibody combination, tixagevimab–cilgavimab, to non-hospitalised adults with mild to moderate COVID-19 has potential to prevent disease progression. We aimed to evaluate the safety and efficacy of tixagevimab–cilgavimab in preventing progression to severe COVID-19 or death.MethodsTACKLE is an ongoing, phase 3, randomised, double-blind, placebo-controlled study conducted at 95 sites in the USA, Latin America, Europe, and Japan. Eligible participants were non-hospitalised adults aged 18 years or older with a laboratory-confirmed SARS-CoV-2 infection (determined by RT-PCR or an antigen test) from any respiratory tract specimen collected 3 days or less before enrolment and who had not received a COVID-19 vaccination. A WHO Clinical Progression Scale score from more than 1 to less than 4 was required for inclusion and participants had to receive the study drug 7 days or less from self-reported onset of mild to moderate COVID-19 symptoms or measured fever. Participants were randomly assigned (1:1) to receive either a single tixagevimab–cilgavimab 600 mg dose (two consecutive 3 mL intramuscular injections, one each of 300 mg tixagevimab and 300 mg cilgavimab) or placebo. Randomisation was stratified (using central blocked randomisation with randomly varying block sizes) by time from symptom onset, and high-risk versus low-risk of progression to severe COVID-19. Participants, investigators, and sponsor staff involved in the treatment or clinical evaluation and monitoring of the participants were masked to treatment-group assignments. The primary endpoints were severe COVID-19 or death from any cause through to day 29, and safety. This study is registered with ClinicalTrials.gov, NCT04723394.FindingsBetween Jan 28, 2021, and July 22, 2021, 1014 participants were enrolled, of whom 910 were randomly assigned to a treatment group (456 to receive tixagevimab–cilgavimab and 454 to receive placebo). The mean age of participants was 46·1 years (SD 15·2). Severe COVID-19 or death occurred in 18 (4%) of 407 participants in the tixagevimab–cilgavimab group versus 37 (9%) of 415 participants in the placebo group (relative risk reduction 50·5% [95% CI 14·6–71·3]; p=0·0096). The absolute risk reduction was 4·5% (95% CI 1·1–8·0; p<0·0001). Adverse events occurred in 132 (29%) of 452 participants in the tixagevimab–cilgavimab group and 163 (36%) of 451 participants in the placebo group, and were mostly of mild or moderate severity. There were three COVID-19-reported deaths in the tixagevimab–cilgavimab group and six in the placebo group.InterpretationA single intramuscular tixagevimab–cilgavimab dose provided statistically and clinically significant protection against progression to severe COVID-19 or death versus placebo in unvaccinated individuals and safety was favourable. Treating mild to moderate COVID-19 earlier in the disease course with tixagevimab–cilgavimab might lead to more favourable outcomes.FundingAstraZeneca.

Immune response during regional chemotherapy.

e14537 Background: Regional chemotherapy is known to yield high drug concentrations in the treated tumor area while keeping systemic drug concentrations low. Regional Chemotherapy can be performed as an intra arterial infusion or isolated perfusion. Known perfusion techniques are isolated limb perfusion, hypoxic pelvic perfusion, hypoxic abdominal perfusion, upper abdominal perfusion, and isolated thoracic perfusion, Only little is known on the effect of chemotherapy on immune cells, especially not if chemotherapy is applied regionally. Since more and more immuno oncologic treatment possibilities arise, that often are combined with chemotherapy, knowledge on the effects on immune cells is crucial. Since systemic chemotherapy often decreases the number of immune cells in general, the more targeted approach of regional chemotherapy is investigated in this study. Methods: In this work, we investigate subpopulations of T-lymphocytes, Natural Killer cells and B-lymphocytes during regional chemotherapy and report on their changes after cycles of intra-arterial chemotherapy infusion followed by chemofiltration. Surface phenotyping of cells from EDTA blood was performed with combinations of monoclonal antibodies (anti- CD3,CD16, CD56, CD45, CD4, CD19, CD8, CD28, HLA-DR, CD39, CD25, CD127, CD45RA, CD45RO) for FACS analysis. 58 Patients with advanced breast cancer, ovarian cancer, head and neck cancer, lung cancer, or bladder cancer received regional chemotherapy as an intra arterial infusion therapy or an isolated perfusion therapy. Results: Contrary to the mild immune cell depletion during the first two cycles a more activated immune status is seen after treatment cycle three. Non-significant increase or stable numbers are observed for T-Lymphocytes and its subsets of CD4+ T-helper cells, CD8+ cytotoxic T-cells, and terminal memory T-cells (CD8+/CD28-/CD57+). Significant increase of cell numbers is observed for B-lymphocytes, regulative CD8+ T-cells (CD8+/CD28-/CD57-), activated HLA-DR+ T cells, and Natural Killer cells while regulative CD4+ T cells are significantly decreased. Conclusions: The data show that regional chemotherapy has controversial effects on the immune cell subpopulations. As every chemotherapy, it does affect immune cells, however to a limited extend, but importantly has an activating potential. Immune activation prevalently takes place after the third cycle of therapy which might be a hint for auto-vaccination caused by phases of repeated tumor necrosis after locally high drug concentrations. Finding the optimal dosage of chemotherapeutics may be crucial to balance direct tumor response, immune toxicity and immune activation.

Tixagevimab + Cilgavimab: First Approval.

Tixagevimab 150 mg and cilgavimab 150 mg (EVUSHELDTM 150 mg + 150 mg solution for injection; tixagevimab + cilgavimab) is an intramuscular (IM) long-acting monoclonal antibody combination developed by AstraZeneca for the prevention and treatment of COVID-19. In March 2022, tixagevimab + cilgavimab was approved in the UK for pre-exposure prophylaxis of COVID-19 in adults who are not currently infected with SARS-CoV-2 and who have not had a known recent exposure to an individual infected with SARS-CoV-2 and who are unlikely to mount an adequate immune response to COVID-19 vaccination or for whom COVID-19 vaccination is not recommended, and in the EU for the prevention of COVID-19 in adults and adolescents aged ≥ 12 years and weighing ≥40 kg. In December 2021, tixagevimab + cilgavimab was granted Emergency Use Authorization by the US FDA for the pre-exposure prophylaxis of COVID-19 in adults and paediatric individuals (≥ 12 years of age and weighing ≥ 40 kg). This article summarizes the milestones in the development of tixagevimab + cilgavimab leading to this first approval for pre-exposure prophylaxis of COVID-19 in individuals who are not currently infected with SARS-CoV-2.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40265-022-01731-1.

1198-P: Prevention of COVID-with Subcutaneous Administration of CAS+IMD in Individuals with Diabetes and Other Risk Factors for Severe Disease

Background: Subcutaneous (SC) administration of the monoclonal antibody combination casirivimab and imdevimab (CAS+IMD) decreased the risk of COVID-in a phase 3 trial of uninfected adolescents/adults who shared a household with a SARS-CoV-2–infected individual (NCT04452318) . Here, we present a subgroup analysis of this study, assessing the efficacy and safety of CAS+IMD in preventing symptomatic COVID-in individuals with diabetes and other risk factors for progression to severe disease. Methods: Healthy individuals aged ≥12 years, identified within 96 hours of collection of a positive test from a household contact, were randomized 1:1 to receive SC CAS+IMD 1200 mg or placebo. The primary endpoint was the proportion of participants who developed symptomatic COVID-during the 28-day efficacy assessment period among those who were SARS-CoV-2 RT-qPCR negative at baseline. Post hoc analyses assessed efficacy and safety by diabetes history, body mass index (BMI) , and the presence/absence of ≥1 high-risk factor for severe COVID-19. Results: The efficacy analysis included 2067 participants who were enrolled from July 13, 2020–January 28, 2021 and were RT-qPCR negative at baseline. In participants with diabetes (n=139) , the relative risk reduction (RRR) of developing symptomatic COVID-with CAS+IMD vs. placebo was 76.3%. Similar results were observed in participants with BMI ≥30 kg/m2 (n=728; RRR=74.9%) and in those with ≥1 high-risk factor for severe COVID-at baseline (n=620; RRR=77.5%) . Across subgroups, injection-site reaction was more common with CAS+IMD versus placebo whereas asymptomatic COVID-19, COVID-19, and headache were more common with placebo versus CAS+IMD. Conclusions: In study participants with diabetes and those with other risk factors for severe COVID-19, treatment with SC CAS+IMD decreased the risk of developing symptomatic COVID-19, consistent with results in the overall population. Disclosure M.O'brien: Employee; Regeneron Pharmaceuticals Inc., Other Relationship; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. R.V.Barnabas: Other Relationship; Regeneron Pharmaceuticals Inc. M.S.Cohen: Other Relationship; COVPN, Fogarty, HPTN, McGill, National Institutes of Health, Prime Global Options, Regeneron Pharmaceuticals Inc. A.Mahmood: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. G.A.Herman: Employee; Regeneron Pharmaceuticals Inc., Other Relationship; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. G.D.Yancopoulos: Employee; Regenacy Pharmaceuticals, Inc., Other Relationship; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. D.M.Weinreich: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. The covid-phase 3 prevention trial team: n/a. E.Forleo-neto: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. E.Oviedo orta: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. J.Mcginniss: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. P.Hou: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. F.Isa: Employee; Regeneron Pharmaceuticals Inc., Other Relationship; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. K.Chan: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. N.Sarkar: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. B.J.Musser: Employee; Regeneron Pharmaceuticals Inc., Stock/Shareholder; Regeneron Pharmaceuticals Inc. Funding Supported by Regeneron Pharmaceuticals, Inc., and F. Hoffmann-La Roche Ltd. This trial was conducted jointly with the COVID-Prevention Network, which was funded by the National Institute of Allergy and Infectious Diseases (NIAID) , National Institutes of Health (NIH) .

Safety of dual checkpoint-blockade with PSB205, an anti-PD-1/CTLA4 monoclonal antibody combination, manufactured and dispensed as a single product: A phase 1 study.

2611 Background: PSB205 is a new biological agent consisting of two engineered monoclonal antibodies (anti-PD-1 IgG4 and anti-CTLA-4 IgG1) expressed in a fixed ratio (2:1) from a single cell-line, manufactured as one product and dispensed from a single vial. PSB205 was designed to optimally balance efficacy and safety through differential target coverage of PD-1 and CTLA-4: the anti-CTLA-4 antibody was engineered to have a shorter half-life to modulate exposure and lower risk of immune-related adverse events (irAEs). Methods: We report safety data from a first-in-human study, conducted in standard 3+3 Phase 1 dose escalation format, enrolling subjects with refractory solid tumors with mixed histologies, who had exhausted available standard treatments. Primary objectives were safety (including Dose Limiting Toxicities), tolerability and selection of a Phase 2 dose. Secondary objectives were PK and preliminary evaluation of effectiveness. Treatment was Q3 wks. Inclusive the 1st week following the 2nd infusion, the DLT-period was 28 days. Results:Nine US-centers enrolled 27 subjects, representing 19 tumor histologies, in 5 ascending dose cohorts ranging from 0.1 mg/kg to 5 mg/kg; an additional N = 49 pts were dosed in expansion cohorts at 5 mg/kg and 400 mg (fixed dose). Median number of prior systemic treatments for metastatic disease was 4. No DLT was observed at any of dose level evaluated. The most frequent Treatment-Related Adverse Events (TRAE) reported were diarrhea (9%), Infusion-Related Reaction (IRR) (5%) and fatigue (4%). Among the subset (N = 33) who completed at least 4 cycles of treatment, the most common TRAE were diarrhea (21%), IRR (12%), Fatigue (9%), and irAEs, specifically colitis, rash and arthralgia (6% each symptom). Most TRAEs were Grade 1 /2, with just 1 case each of diarrhea and colitis Graded as G 3/4. Tumor responses (all PRs) were observed at dose levels of 3 mg/kg and 5 mg/kg in 4 pts - 1 each with with RCC, SCLC, HNSCC and gastric cancer. Conclusions: PSB205 provides dual checkpoint blockade with a very tolerable side effect profile, with less AEs than typically noted in published studies of anti-PD1 and anti-CTLA-4 combination therapy. Further studies are ongoing to confirm this observation. Dose levels of 5 mg/kg and 400 mg fixed were selected for Phase 2, which has commenced enrollment. Clinical trial information: NCT03986606.