MC-SN38 is a drug-linker conjugate composed of a potent microtubule-disrupting agent SN38 and a non-cleavable MC linker to make antibody drug conjugate (ADC). SN-38, an active metabolite of the Topoisomerase I inhibitor Irinotecan, inhibits DNA synthesis and causes frequent DNA single-strand breaks[1][2].
[1]. Jensen NF, et al. Characterization of DNA topoisomerase I in three SN-38 resistant human colon cancer cell lines reveals a newpair of resistance-associated mutations. J Exp Clin Cancer Res. 2016 Mar 31;35:56.
[2]. Kawato Y, et al. Intracellular roles of SN-38, a metabolite of the camptothecin derivative CPT-11, in the antitumor effect of CPT-11. Cancer Res. 1991;51(16):4187-4191.