Anaysis of antibody escape showing variant A.27 completely escaped neutralization with LY-COV555 and partially with REGN10987. B.1.617.2 escaped these antibodies in a similar manner, suggesting that L452R facilitates the escape. Authors note that B.1.351 and P.1 escaped LY-COV555 and REGN10933, likely facilitated by the E484K mutation, suggesting that L452R and E484K lead to escape from LY-COV555 and to partial resistance to either REGN10987 or REGN10933, respectively.
Kaleta et al., 2 Nov 2021, preprint, 33 authors.
In Vitro studies are an important part of preclinical research, however results may be very different in vivo.