“The rat was chosen as the relevant animal species for the repeat-dose toxicity study, based on the rationale that systemic exposure of clesrovimab in the rats were sufficient to cover the anticipated clesrovimab exposure in humans.”
Viral target not expressed in any species; no off-target effects expected, so rat used to avoid unnecessary NHP use (3R)
“It was therefore agreed that, as no relevant toxicological species exists and no off-target effects were expected in neither NHPs nor in rats, the use of the rat is supported from a 3R perspective in order to avoid unnecessary use of NHPs.”
No surrogate; the clinical antibody was tested in rats
“MK-1654 (clesrovimab) nonclinical safety studies included a good laboratory practice (GLP) 2- week IV/IM repeat-dose toxicology study in Wistar Han rats with a 4-week recovery period”
“MK-1654 (clesrovimab) nonclinical safety studies included a good laboratory practice (GLP) 2- week IV/IM repeat-dose toxicology study in Wistar Han rats with a 4-week recovery period”
Not conducted (exogenous viral target, ICH S6(R1)); no reproductive toxicity in 2-week rat study
“In accordance with ICH S6(R1), DART studies are generally not needed for biologics to exogenous targets. In addition, no male or female reproductive toxicities were observed in the 2-week repeat-dose toxicology study in rats (Study TT #16-1029)”
No surrogate used; clinical antibody tested in rats
“MK-1654 (clesrovimab) nonclinical safety studies included a good laboratory practice (GLP) 2- week IV/IM repeat-dose toxicology study in Wistar Han rats with a 4-week recovery period”