Increased spleen weight in female mice without other immune findings; immunotoxicity risk low
“Resmetirom induced an increase in spleen weight of female mice at 3 and 100 mg/kg/day dose, however since correlation with other immune-related finding was not observed, the risk of immunotoxicity was considered low.”
Liver ~10x and renal cortex ~3x plasma AUC; no melanin association in pigmented rats
“Liver AUC and renal cortex AUC for total radioactivity after dosing with [14C]MGL-3196 were approximately 10 times and 3 times the plasma AUC value, respectively. [14C]MGL-3196-related radioactivity was not specifically associated with the melanin-containing tissues in the pigmented LE rats.”
Disproportionate major human metabolite MGL-3623 (MIST) required separate toxicity testing
“MGL-3623, a major (disproportionate) human metabolite of resmetirom, was tested in a 3-month oral toxicity study in CD-1 mice at doses up to 100 mg/kg/day”