Erlotinib-13C6 (CP-358774-13C6) is a 13C-labeled Erlotinib. Erlotinib is a directly acting EGFR tyrosine kinase inhibitor, with an IC50 of 2 nM for human EGFR[1].

Erlotinib reduces EGFR autophosphorylation in intact tumor cells with an IC50 of 20 nM. Erlotinib is used for the treatment of non-small cell lung cancer[1].Stable heavy isotopes of hydrogen, carbon, and other elements have been incorporated into drug molecules, largely as tracers for quantitation during the drug development process[2].