Last updated: October 14, 2020
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Monoclonal antibodies are a type of therapeutic agent under investigation for the treatment of COVID-19. These agents are often created by identifying pathogen-specific B cells of patients who have recently recovered from an infection or by utilizing mice genetically modified to have an immune system (Marovich, June 2020). Once the B cells are identified, the genes of immune globulin heavy and light chains are recovered. These genes are then expressed to produce monoclonal antibodies. Monoclonal antibodies have singular activity against a predetermined target; they therefore differ from convalescent plasma, which consists of polyclonal antibodies in serum derived from patients who are convalescing from an infection (Marston, April 2018). Monoclonal antibodies have been developed for the treatment and prophylaxis of other viral infections, such as HIV, influenza, RSV, MERS-CoV, Ebola and Zika virus (Walker, January 2018). Of these, only monoclonal antibodies targeting RSV and Ebola have been shown to be effective in human trials (with the former having FDA approval) (Marovich, June 2020). Several products targeting the other aforementioned viruses are currently being studied in clinical trials.
The majority of monoclonal antibody products under development for SARS-CoV-2 target the spike protein, which the virus utilizes to enter host cells (Marovich, June 2020). Available clinical data on the therapeutic use of these agents is limited; phase 2/3 trials are underway, and it is not known when complete data from those studies will be shared. To date, the only clinical trial data available to the public has been in the form of press releases from Eli Lilly and Regeneron pharmaceuticals. In October 2020 both companies applied for emergency use authorization from FDA based on internal results from the trials in progress. Eli Lilly’s monoclonal antibody regimen consists of 2 antibodies directed against the SARS-CoV-2 spike protein and its receptor binding domain; Regeneron’s product, REGN-COV2, consists of 2 antibodies that bind to different regions of the SARS-CoV-2 spike protein receptor binding domain.
ACTIV-3 is an NIH-sponsored phase 3 clinical trial of one of Eli Lilly's monoclonal antibodies, comparing LY-CoV555 and remdesivir against placebo and remdesivir in patients who have been hospitalized with mild or moderate COVID-19. On October 13, 2020, the trial's independent data safety monitoring board recommended a pause of the study after noting the group of patients who had received 5 days of LY-CoV555 had a different clinical status than the group who had received placebo. Further information is forthcoming.
A review of the literature on this topic will be developed once relevant clinical data in humans are made fully available to the public.