Phage-derived anti-idiotype and anti-YTEantibodies in development of MK-1654pharmacokinetic and immune responseassays: supplementary figures

Background: MK-1654 is a fully human monoclonal antibody with YTE mutations currently in phase III

clinical trials for prophylactic use in protecting infants from human respiratory syncytial virus infection.

Materials & methods: We generated anti-idiotype (anti-ID) and anti-YTE antibodies against MK-1654 by

panning with MorphoSys HuCal phage libraries, and used the antibodies in the development of MK-

1654 pharmacokinetic (PK) and immune response (IR) assays. Results: Detection of MK-1654 in nonhuman

primate and human nasal wash samples showed combined use of anti-ID and anti-YTE antibodies can

deliver desired sensitivity and accuracy in PK studies. IR studies showed anti-ID can serve as suitable positive

control in neutralizing antibody assays. Conclusion: Phage-derived anti-IDs and anti-YTEs are suitable for

PK and IR assays.