The us food and drug administration (fda) has granted approval to regeneron pharmaceuticalsÒ€ℒ fully human monoclonal antibody libtayo(cemiplimab-rwlc) as an adjuvant therapy for adults with During the treatment period ranging from 8 to 19 months in 5 clinical studies, the incidence of anti-cemiplimab-rwlc antibodies in libtayo-treated patients was 2% (22/1029).