IMMUNOPRECISE ANTIBODIES LTD. (the "Company" or "IPA") (NASDAQ: IPA) (TSX VENTURE: IPA) a leader in full-service, therapeutic antibody discovery and development, today announced the identification of antibody 23-H7, which preclinical data obtained to date indicates provides strong, protective anti-viral effects in SARS-CoV-2 (COVID-19) infected Syrian hamsters via an uncommon mechanism of action.
While 23-H7 is able to perturb the interaction between the Receptor Binding Domain (RBD) and the host receptor ACE2, its epitope is not located on the mutation prone RBD/ACE2 interface, unlike the spike protein regions targeted by current, commercial SARS-CoV-2 therapies. As a result, 23-H7 is anticipated to be less vulnerable to escape mutations within the spike protein/ACE2 binding interface, like escape mutation of concern E484K. In line with this, IPA demonstrated that 23-H7 maintained binding to the full (cell-associated) spike trimer of emerging SARS-CoV-2 variants of concern B.1.1.7 (UK), B.1.351 (S. African), and P.1 (Brazilian), despite published data stating that many highly neutralizing antibody therapies against SARS-CoV-2, as well as most convalescent sera and vaccine-induced immune sera, show reduced activity against viral variants.
Notably, in vivo efficacy evaluation of antibody 23-H7 when administered as a passive vaccine, twenty-four hours prior to infecting Syrian hamsters with the SARS-CoV-2-D614G, resulted in undetectable replication competent virus titer in the lungs of four of the five animals 4 days post infection, with the remaining animal showing a replication competent viral titer barely above the lowest level of detection. As binding of this antibody to multi- and single-mutated spike protein trimers and fragments, respectively, appears to be unaffected, IPA anticipates that this antibody has the potential to maintain similar in vivo protective efficacy against corresponding viral variants.
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