Development and pre-clinical characterization of two therapeutic equine formulations towards SARS-CoV-2 proteins for the potential treatment of COVID-19

Abstract

In the current global emergency due to SARS-CoV-2 outbreak, passive immunotherapy emerges as a promising treatment for COVID-19. Among animal-derived products, equine formulations are still the cornerstone therapy for treating envenomations due to animal bites and stings. Therefore, drawing upon decades of experience in manufacturing snake antivenom, we developed and preclinically evaluated two anti-SARS-CoV-2 polyclonal equine formulations as potential alternative therapy for COVID-19. We immunized two groups of horses with either S1 (anti-S1) or a mixture of S1, N, and SEM mosaic (anti-Mix) viral recombinant proteins. Horses reached a maximum anti-viral antibody level at 7 weeks following priming, and showed no major adverse acute or chronic clinical alterations. Two whole-IgG formulations were prepared via hyperimmune plasma precipitation with caprylic acid and then formulated for parenteral use. Both preparations had similar physicochemical and microbiological quality and showed ELISA immunoreactivity towards S1 protein and the receptor binding domain (RBD). The anti-Mix formulation also presented immunoreactivity against N protein. Due to high anti-S1 and anti-RBD antibody content, final products exhibited high in vitro neutralizing capacity of SARS-CoV-2 infection, 80 times higher than a pool of human convalescent plasma. Pre-clinical quality profiles were similar among both products, but clinical efficacy and safety must be tested in clinical trials. The technological strategy we describe here can be adapted by other producers, particularly in low- and middle-income countries.

The Road towards Polyclonal Anti-SARS-CoV-2 Immunoglobulins (Hyperimmune Serum) for Passive Immunization in COVID-19

“…Since plasma-derived drugs could theoretically suffer from many problems, including low potency, impurities (including infectious viruses [ 37 ] and clotting factors [ 38 ]), constraints on supply, the antibody-dependent enhancement (ADE) of infection, and batch-to-batch variation [ 39 ], polyvalent, 10 3 - to 10 4 -diverse recombinant hyperimmune antibody drugs generated from convalescent human blood donors, vaccinated human blood donors, and humanized animal repertoires will likely be an additional field of research for the coming years [ 40 ].…”

Analysis of anti-Omicron neutralizing antibody titers in different vaccinated and unvaccinated convalescent plasma sources

“…Given the success of CCP in 2 outpatient RCTs reducing hospitalization 14,15 and the loss of major mAb therapies due to Omicron antigenic changes, the high titers in CCP collected from vaccinated convalescents provides an immediate option for COVID-19, especially in LMIC. Given the reduced hospitalization rate with Omicron compared to Delta 52,53 , it is even more relevant to identify patient subsets at risk of progression in order to minimize the number needed to treat to prevent a single hospitalization: moving from the same criteria used for mAb therapies while using the same (now unused) in-hospital facilities seems a logical approach.…”

History repeats itself: horse originated hyperimmune sera production against SARS CoV-2

“…León et al, [15] injected two groups of three horses each, with either S1 (anti-S1) or a mixture of S1, N, and SEM mosaic (anti-Mix) viral recombinant protein, and the maximum anti-SARS-CoV-2 polyclonal antibody level (approximately 80 times more than convalescent serum) was reached at the end of seven weeks. The results obtained indicated that an antibody titer of 1:25355 was obtained for anti-Mix in horses.…”