SN-38

SN-38 is the active metabolite of irinotecan (an analog of camptothecin - a topoisomerase I inhibitor); it is 200 times more active than irinotecan itself.

SN38 is metabolized via glucoronidation by UGT1A1.

The variant of UGT1A1 in ~10% of Caucasians which leads to poor metabolization of Irinotecan predicts Irinotecan toxicity, as it cannot be excreted from the body in its SN-38 form.

SN-38 is lost into the bile and feces. It can cause the symptoms of diarrhoea and myelosuppression experienced by ~25% of the patients administered Irinotecan.