Enflonsia: which tox species, and why?

“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.”

“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.”

“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”