Monoclonal Antibody Cocktail therapy for COVID-19: A Pharmacological innovation

The novel SARS-CoV-2 infection has ripped through international health systems and protocols causing unprecedented mortality, morbidity and global trade deficits amounting to billions. Various monoclonal antibodies have been proposed for use in the treatment of COVID-19 infections. One such drug is LY-CoV555 which in an ongoing phase two trial study conducted by Chen P et al, showed to have an elimination of 99.97% of the viral RNA. The monoclonal antibody 47D11 discovered by Wang et al, binds to SARS-CoV-2. The 47D11 has been reconfigured into a human IgG1 isotope. It has shown that the 47D11 mAb effectively neutralizes the SARS-COV-2 virus. The stance and development however for the treatment of COVID-19 with monoclonal antibodies has shifted from a monotherapy to a so-called monoclonal antibody “cocktail” therapy. REGN-COV2 is such a cocktail developed with the use of two monoclonal antibodies REGN10987 and REGN10933 which have subsequently been named Imdevimab and Casirivimab. REGN-COV2 is currently under study in four phase 2 and 3 trial studies. These studies are multicentric in nature and are being conducted to evaluate the drug’s efficacy, dosing and clinical use as compared to the placebo. The mechanism of action of such monoclonal antibodies is related chiefly to the inhibition of the virus’s ability to perform its invasion and multiplication within the human body. The severity coupled with the sheer novelty of the SARSCoV-2 virus demands the use of newer therapies to both decrease the mortality and morbidity in patients suffering from the infection. The use of a combination of monoclonal antibodies is thereby well established and evident to both decrease the viral infection load, but is also useful in disrupting the virus’s life cycle and thus decreases the replication and viral shedding. It is therefore poignant that a combination of monoclonal antibodies, a “cocktail” therapy is employed so as to attack the virus at its various stages and thus this multifaceted approach may enhance the patient’s prognosis.

Using antibody synergy to engineer a high potency biologic cocktail against C. difficile

We applied a mathematical framework originally used to model the effects of multiple inhibitors on enzyme activity to guide the development a therapeutic antibody cocktail, LMN-201, to prevent and treat C. difficile infection (CDI). CDI causes hundreds of thousands of cases of severe, often recurrent diarrhea and colitis in the United States annually and is associated with significant morbidity and mortality worldwide. Current therapies for preventing recurrent CDI are only partially successful, and there are no options available to prevent initial bouts of CDI in at-risk populations. Almost all antibody therapies have been developed and administered as monotherapies. Antibody cocktails are relatively rare even though they have the potential to greatly increase efficacy. One reason for this is our limited understanding of how antibody interactions can enhance potency, which makes it difficult to identify and develop antibodies that can be assembled into optimally effective cocktails. In contrast to the view that antibody synergies depend on unusual instances of cooperativity or allostery, we show that synergistic efficacy requires nothing more than that the antibodies bind independently to distinct epitopes on a common target. Therefore, synergy may be achieved much more readily than is generally appreciated. Due to synergy the LMN-201 antibody cocktail, which targets the C. difficile exotoxin B (TcdB), is 300- to 3000-fold more potent at neutralizing the most clinically prevalent TcdB toxin types than bezlotoxumab, the only monoclonal antibody currently approved for treatment or prevention of CDI. The efficacy of LMN-201 is further enhanced by inclusion of a phage-derived endolysin that destroys the C. difficile bacterium, and which therefore has a complementary mechanism of action to the antibody cocktail. These observations may serve as a paradigm for the development of high potency biologic cocktails against targets that have proven challenging for single-agent therapies.

ZRC3308 Monoclonal Antibody Cocktail Shows Protective Efficacy in Syrian Hamsters against SARS-CoV-2 Infection

We have developed a monoclonal antibody (mAb) cocktail (ZRC-3308) comprising of ZRC3308-A7 and ZRC3308-B10 in the ratio 1:1 for COVID-19 treatment. The mAbs were designed to have reduced immune effector functions and increased circulation half-life. mAbs showed good binding affinities to non-competing epitopes on RBD of SARS-CoV-2 spike protein and were found neutralizing SARS-CoV-2 variants B.1, B.1.1.7, B.1.351, B.1.617.2, and B.1.617.2 AY.1 in vitro. The mAb cocktail demonstrated effective prophylactic and therapeutic activity against SARS-CoV-2 infection in Syrian hamsters. The antibody cocktail appears to be a promising candidate for prophylactic use and for therapy in early COVID-19 cases that have not progressed to severe disease.

Antibody cocktail effective against variants of SARS-CoV-2

Background Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an RNA virus with a high mutation rate. Importantly, several currently circulating SARS-CoV-2 variants are associated with loss of efficacy for both vaccines and neutralizing antibodies. Methods We analyzed the binding activity of six highly potent antibodies to the spike proteins of SARS-CoV-2 variants, assessed their neutralizing abilities with pseudovirus and authentic SARS-CoV-2 variants and evaluate efficacy of antibody cocktail in Delta SARS-CoV-2-infected hamster models as prophylactic and post-infection treatments. Results The tested RBD-chAbs, except RBD-chAb-25, maintained binding ability to spike proteins from SARS-CoV-2 variants. However, only RBD-chAb-45 and -51 retained neutralizing activities; RBD-chAb-1, -15, -25 and -28 exhibited diminished neutralization for all SARS-CoV-2 variants. Notably, several cocktails of our antibodies showed low IC50 values (3.35–27.06 ng/ml) against the SARS-CoV-2 variant pseudoviruses including United Kingdom variant B.1.1.7 (Alpha), South Africa variant B.1.351 (Beta), Brazil variant P1 (Gamma), California variant B.1.429 (Epsilon), New York variant B.1.526 (Iota), and India variants, B.1.617.1 (Kappa) and B.1.617.2 (Delta). RBD-chAb-45, and -51 showed PRNT50 values 4.93–37.54 ng/ml when used as single treatments or in combination with RBD-chAb-15 or -28, according to plaque assays with authentic Alpha, Gamma and Delta SARS-CoV-2 variants. Furthermore, the antibody cocktail of RBD-chAb-15 and -45 exhibited potent prophylactic and therapeutic effects in Delta SARS-CoV-2 variant-infected hamsters. Conclusions The cocktail of RBD-chAbs exhibited potent neutralizing activities against SARS-CoV-2 variants. These antibody cocktails are highly promising candidate tools for controlling new SARS-CoV-2 variants, including Delta.

REGEN-COV® antibody cocktail bioanalytical strategy: comparison of LC-MRM-MS and immunoassay methods for drug quantification

Aim: In response to the COVID-19 pandemic, Regeneron developed the anti-SARS-CoV-2 monoclonal antibody cocktail, REGEN-COV® (RONAPREVE® outside the USA). Drug concentration data was important for determination of dose, so a two-part bioanalytical strategy was implemented to ensure the therapy was rapidly available for use. Results & methodology: Initially, a liquid chromatography-multiple reaction monitoring-mass spectrometry (LC-MRM-MS) assay, was used to analyze early-phase study samples. Subsequently, a validated electrochemiluminescence (ECL) immunoassay was implemented for high throughput sample analysis for all samples. A comparison of drug concentration data from the methods was performed which identified strong linear correlations and for Bland-Altman, small bias. In addition, pharmacokinetic data from both methods produced similar profiles and parameters. Discussion & conclusion: This novel bioanalytical strategy successfully supported swift development of a critical targeted therapy during the COVID-19 public health emergency.

Role of Steroids and Other Immunomodulators in Treatment of COVID-19

Coronavirus disease 2019(COVID- 19), the newly discovered infectious disease is caused by an infection with a novel virus belonging to the family Coronaviridae named severe acute respiratory syndrome coronavirus-2(SARS-CoV-2). SARS-CoV-2-infected cells produce substances that can induce injury to lung cells as the focus of initiation of COVID-19 during the incubation period. These substances bind to receptors on the target cells. Corticosteroids bind to specific intracellular cytoplasmic receptors in target tissues. The receptor hormone recruits co-activator or co-repressor proteins after dimerizing. In severe COVID-19 patients develop a systemic inflammatory response that leads to lung injury and multisystem organ dysfunction. Even though evidence consistently supporting the use of steroids in ARDS and pneumonia is hard to come by the potent anti-inflammatory effects of steroids are postulated to prevent the deleterious effects of the severe inflammation seen in COVID pneumonia. A monoclonal antibody cocktail consisting of Casirivimab and Imdevimab is another promising therapeutic option in patients at high risk of deterioration. Used early in the disease process they prevent hospitalization and further morbidity.

TAMI-23. ANTIBODY COCKTAIL IMMUNOTHERAPY FOR GLIOBLASTOMA BY DUAL TARGETING OF IL-6 AND CD40

Glioblastoma (GBM) is refractory to current T cell-based immunotherapies such as checkpoint blockade. GBM is characterized by extensive infiltration of immunosuppressive macrophages that contribute to the treatment resistance. Here we develop a dual-targeting strategy to synergistically activate tumor-associated macrophages (Mφs), which efficiently overcomes GBM resistance to therapeutic blockade of the PD1 and CTLA4 checkpoints. Consistent with a pro-tumor role of IL-6 in alternative Mφ polarization, we here show that targeting IL-6 by genetic ablation or pharmacological inhibition moderately improves T-cell infiltration into GBM and enhances mouse survival; however, IL-6 inhibition does not synergize PD-1 and CTLA-4 checkpoint blockade. Interestingly, anti-IL-6 therapy reduces CD40 expression in GBM-associated Mφs. We identify a Stat3/HIF-1α-mediated axis, through which IL-6 executes an anti-tumor role to induce CD40 expression in Mφs. Combination of IL-6 inhibition with CD40 stimulation reverses Mφ-mediated tumor immunosuppression, sensitizes tumors to checkpoint blockade, and extends animal survival in two syngeneic GBM models. Notably, this antibody cocktail-based combination immunotherapy with checkpoint blockade almost doubles animal survival in the genetically engineered mouse GBM model and induces complete tumor regression in the GL261 model. Thus, antibody cocktail-based immunotherapy that combines checkpoint blockade with dual-targeting of IL-6 and CD40 may offer exciting therapeutic opportunities for GBM.

Structure-guided antibody cocktail for prevention and treatment of COVID-19

Development of effective therapeutics for mitigating the COVID-19 pandemic is a pressing global need. Neutralizing antibodies are known to be effective antivirals, as they can be rapidly deployed to prevent disease progression and can accelerate patient recovery without the need for fully developed host immunity. Here, we report the generation and characterization of a series of chimeric antibodies against the receptor-binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein. Some of these antibodies exhibit exceptionally potent neutralization activities in vitro and in vivo, and the most potent of our antibodies target three distinct non-overlapping epitopes within the RBD. Cryo-electron microscopy analyses of two highly potent antibodies in complex with the SARS-CoV-2 spike protein suggested they may be particularly useful when combined in a cocktail therapy. The efficacy of this antibody cocktail was confirmed in SARS-CoV-2-infected mouse and hamster models as prophylactic and post-infection treatments. With the emergence of more contagious variants of SARS-CoV-2, cocktail antibody therapies hold great promise to control disease and prevent drug resistance.

Impact of Antibody Cocktail Therapy Combined with Casirivimab and Imdevimab on Clinical Outcome for Covid-19 patients in A Real-Life Setting: A Single Institute Analysis

ABSTRACT Background. Recent data from clinical trial suggest that antibody cocktail therapy, a combination of the monoclonal antibodies casirivimab and imdevimab, has been shown to rapidly reduce the viral load and markedly decrease the risk of hospitalization or death among high-risk patients with coronavirus disease 2019 (Covid-19). However, it remains unclear how effective in a real-life clinical setting the therapy is. Methods. We retrospectively analyzed mild to moderate Covid-19 patients with one or more high-risk factors for severe disease who consecutively underwent the antibody cocktail therapy of the disease in our institute in June 2021 through early September 2021, compared to those with high-risk factors who were isolated in non-medical facilities consecutively during the same period, thereby being not given the antibody cocktail therapy there. The key outcome was the percentage of patients with Covid-19-related deterioration which needed additional medical interventions, such as oxygen support or other antiviral therapies. Results. Data from 55 patients with initially receiving antibody cocktail therapy and 53 patients with isolation into non-medical facilities are analyzed. 22 (41.5 %) of 53 patients with isolation facilities were finally hospitalized to receive medical interventions. On the other hand, 13 (23.6 %) of 55 patients with antibody cocktail therapy in our hospital subsequently underwent further medical interventions because of the progression. In multivariate analysis with variables of age, BMI, and high-risk factors, the antibody cocktail therapy significantly reduced 70 % in the need for further medical interventions compared to the initial isolation in the non-medical facilities (odds ratio=0.30, 95%CI [0.10-0.87], p=0.027). Furthermore, patients with 96% or above of SPO2 were significantly more favorable for the therapy than those with 95% or below of SPO2. Conclusion. The treatment of antibody cocktail was closely linked to reduction in the need for further medical interventions. The result indicates that the antibody cocktail therapy is associated with reducing the strain on hospitals, which is related to the improvement of medical management for public health care in Covid-19 pandemic era.