Immune system (thymus, spleen, lymph nodes) a target organ in dog studies
“The non-GLP dog studies identified liver, kidney, GI-tract, adrenal gland, and immune system (thymus and spleen, and lymph nodes in the 39-week study) as target organs.”
Wide distribution; highest in GI tract, bladder, uveal tract and pigmented skin (melanin)
“Following a single oral dose of radiolabeled fruquintinib, wide distribution of fruquintinib was observed with the highest radioactivity observed in the esophagus, large intestine, small intestine, stomach, bladder, uveal tract, and pigmented skin.”
✓ VerifiedFDA multi-discipline review, p. 32Source ↗
Modality-specific risk
Low exposure margins: 13-week rat and dog NOAEL AUC ratios 0.3 and 0.05
“The safety margins (total AUC ratio) derived from the GLP-compliant 13-week rat and dog study NOAELs are 0.3 and 0.05, respectively.”