Beyfortus: animal efficacy model or human cells?

“In Zhu et al, 2017, the antiviral activity of 1G7 was investigated in vivo by administering 1G7 i.m. at 8 different dose levels to cotton rats 1 day prior to challenging with RSV A2 or RSV B9320 strains at doses up to 3 mg/kg and 1.5 mg/kg, respectively.”

“The YTE modification was added to the mAb to prolong the terminal half-life of the antibody in humans, though the modification significantly decreases antibody exposure in rodents resulting in decreased serum antibody levels relative to the native human Fc. Therefore, the parental molecule, 1G7, was utilized for nonclinical pharmacology studies conducted in rodents.”

“An adequate program of in vitro and in vivo pharmacology was conducted for nirsevimab, including a disease model, supporting the intended clinical use of nirsevimab. Non-clinical proof of concept as an antibody-mediated prophylactic treatment for the prevention of RSV seems established.”