NCI Drug Dictionary

The NCI Drug Dictionary contains technical definitions and synonyms for drugs/agents used to treat patients with cancer or conditions related to cancer. Each drug entry includes links to check for clinical trials listed in NCI's List of Cancer Clinical Trials.

simmitecan hydrochloride
The hydrochloride salt form of simmitecan, an ester prodrug of chimmitecan, a 9-alkyl-substituted camptothecin derivative with potential antineoplastc activity. Upon intravenous administration, simmitecan is hydrolyzed by carboxylesterase and the activated form, chimmitecan, is produced. Chimmitecan inhibits topoisomerase I, stabilizes covalent topoisomerase I-DNA complexes, and inhibits the religation of topoisomerase I-mediated single-strand DNA breaks. Futhermore, the covalent topoisomerase I-DNA complexes interfere and block the DNA replication machinery, resulting in the production of potentially lethal double-strand DNA breaks. This leads to an inhibition of DNA replication and the induction of apoptosis. The modification at position 9 yields improved cytotoxicity compared to some other camptothecin analogues.