Effectiveness of monoclonal antibody therapy for COVID-19 patients using a risk scoring system

The Case for Human Challenge Trials in COVID-19

The COVID-19 pandemic has necessitated rapid research to aid in the understanding of the disease and the development of novel therapeutics. One option is to conduct controlled human infection trials (CHITs). In this article I examine the history of deliberate human infection and CHITs and their utilization prior to the COVID-19 pandemic, key ethical considerations of CHITs in the COVID-19 setting, an analysis of the World Health Organization's (WHO) Key criteria for the ethical acceptability of COVID-19 human challenge studies, and a review of the two COVID-19 CHITs that have already commenced, their compliance with the WHO criteria and other ethical considerations.

Viral target and metabolism-based rationale for combined use of recently authorized small molecule COVID-19 medicines: Molnupiravir, nirmatrelvir, and remdesivir

The COVID-19 pandemic remains a major health concern worldwide, and SARS-CoV-2 is continuously evolving. There is an urgent need to identify new antiviral drugs and develop novel therapeutic strategies. Combined use of newly authorized COVID-19 medicines including molnupiravir, nirmatrelvir, and remdesivir has been actively pursued. Mechanistically, nirmatrelvir inhibits SARS-CoV-2 replication by targeting the viral main protease (Mpro ), a critical enzyme in the processing of the immediately translated coronavirus polyproteins for viral replication. Molnupiravir and remdesivir, on the other hand, inhibit SARS-CoV-2 replication by targeting RNA-dependent RNA-polymerase (RdRp), which is directly responsible for genome replication and production of subgenomic RNAs. Molnupiravir targets RdRp and induces severe viral RNA mutations (genome), commonly referred to as error catastrophe. Remdesivir, in contrast, targets RdRp and causes chain termination and arrests RNA synthesis of the viral genome. In addition, all three medicines undergo extensive metabolism with strong therapeutic significance. Molnupiravir is hydrolytically activated by carboxylesterase-2 (CES2), nirmatrelvir is inactivated by cytochrome P450-based oxidation (e.g., CYP3A4), and remdesivir is hydrolytically activated by CES1 but covalently inhibits CES2. Additionally, remdesivir and nirmatrelvir are oxidized by the same CYP enzymes. The distinct mechanisms of action provide strong rationale for their combined use. On the other hand, these drugs undergo extensive metabolism that determines their therapeutic potential. This review discusses how metabolism pathways and enzymes involved should be carefully considered during their combined use for therapeutic synergy.

Novel Therapeutic Target Critical for SARS-CoV-2 Infectivity and Induction of the Cytokine Release Syndrome

We discovered a novel therapeutic target critical for SARS-CoV-2, cellular infectivity and the induction of the cytokine release syndrome. Here, we show that the mammalian enzyme neuraminidase-1 (Neu-1) is part of a highly conserved signaling platform that regulates the dimerization and activation of the ACE2 receptors and the Toll-like receptors (TLRs) implicated in the cytokine release syndrome (CRS). Activated Neu-1 cleaves glycosylated residues that provide a steric hindrance to both ACE2 and TLR dimerization, a process critical to both viral attachment to the receptor and entry into the cell and TLR activation. Blocking Neu-1 inhibited ACE2 receptor dimerization and internalization, TLR dimerization and activation, and the expression of several key inflammatory molecules implicated in the CRS and death from ARDS. Treatments that target Neu-1 are predicted to be highly effective against infection with SARS-CoV-2, given the central role played by this enzyme in viral cellular entry and the induction of the CRS.

High Anti-CoV2S Antibody Levels at Hospitalization Are Associated with Improved Survival in Patients with COVID-19 Vaccine Breakthrough Infection

BACKGROUND

Although vaccination against COVID-19 is highly effective, breakthrough infections occur, often leading to severe courses and death. The extent of protection provided by individual antibody levels in breakthrough infections is still unknown and cut-off levels have yet to be determined.

METHODS

In 80 consecutive fully vaccinated patients hospitalized between August and December 2021 with COVID-19 breakthrough infection (Delta variant), anti-CoV2S antibody levels were analyzed for the endpoint of death.

RESULTS

Ten out of the 12 patients who died (83.3%) had antibody levels < 600 U/mL; 5 (41.7%) of these had antibody levels < 200 U/mL. Only 2 patients with a level of >600 U/mL died from vaccine breakthrough infection. Correction for the number of comorbidities and age revealed that anti-CoV2S antibody levels at the time of hospitalization were a significant predictor for reduced risk of death (OR = 0.402 for every 1000 U/mL, p = 0.018).

CONCLUSIONS

In this retrospective data analysis, we show that almost all patients who died from COVID-19 vaccine breakthrough infection had antibody levels < 600 U/mL, most of them below 200 U/mL. In logistic regression corrected for the number of comorbidities and age, anti-CoV2S antibody levels at the time of hospitalization proved to be a significantly protective predictor against death.

Antispike monoclonal antibodies for prevention and treatment of coronavirus disease-2019 in solid organ transplant recipients

PURPOSE OF REVIEW

Coronavirus disease-2019 (COVID-19) disproportionately causes severe outcomes in solid organ transplant recipients (SOTR). Antispike monoclonal antibodies have been authorized for therapy and prophylaxis for COVID-19. Here, we review the current state of antispike monoclonal antibodies and their role for SOTRs.

RECENT FINDINGS

Bamlanivimab with or without etesevimab, casirivimab-imdevimab and sotrovimab have reduced the rates of hospitalization and severe disease in high-risk patients with mild-to-moderate COVID-19. Multiple retrospective studies have also demonstrated monoclonal antibodies are effective in SOTR populations. However, the evolution of resistant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concerns has resulted in revocation of the authorization of bamlanivimab with or without etesevimab, and casirivimab-imdevimab as treatment and postexposure prophylaxis (PEP). Sotrovimab and bebtelovimab are currently authorized for treatment of the predominant circulating SARS-CoV-2 B.1.1.529 (Omicron), but not as pre or PEP. Tixagevimab-cilgavimab, a long-acting antibody combination preparation, is authorized for preexposure prophylaxis in high-risk immunocompromised populations, including SOTRs, who are less likely to mount an effective immune response following vaccination series and booster.

SUMMARY

Antispike monoclonal antibodies are useful for the prevention and treatment of mild-to-moderate COVID-19 in SOTRs. However, their clinical use should be determined by the evolving epidemiology of SARS-CoV-2 variants in the community.

Biologics in COVID-19 So Far: Systematic Review

This systematic review aimed to reevaluate the available evidence of the use of biologics as treatment candidates for the treatment of severe and advanced COVID-19 disease; what are the rationale for their use, which are the most studied, and what kind of efficacy measures are described? A search through Cochrane, Embase, Pubmed, Medline, medrxiv.org, and Google scholar was performed on the use of biologic interventions in COVID-19/SARS-CoV-2 infection, viral pneumonia, and sepsis, until 11 January 2022. Throughout the research, we identified 4821 records, of which 90 were selected for qualitative analysis. Amongst the results, we identified five popular targets of use: IL6 and IL1 inhibitors, interferons, mesenchymal stem cells treatment, and anti-spike antibodies. None of them offered conclusive evidence of their efficacy with consistency and statistical significance except for some studies with anti-spike antibodies; however, Il6 and IL1 inhibitors as well as interferons show encouraging data in terms of increased survival and favorable clinical course that require further studies with better methodology standardization.