Extensive distribution; highest in kidney, bone epiphyseal line, skin, liver and esophagus
“In both the pigmented and nonpigmented rats, the highest concentrations of fosdenopterin were observed in the kidney, bone epiphyseal line, skin, liver, and esophagus.”
Phototoxicity: skin reactions and ocular lesions in pigmented rats at >=4.4x MRHD
“A significant safety concern for phototoxicity with fosdenopterin was identified at doses ≥4.4× the maximum recommended human dose of 0.9 mg/kg/day (based on the human equivalent dose [HED]) in a standalone phototoxicity study in rats.”