Nemorubicin HCL is the salt form of Nemorubicin, also known as PNU152243A, a doxorubicin derivative that differs significantly from its parent drug in terms of spectrum of antitumor activity, metabolism and toxicity profile. The drug is active on tumors resistant to alkylating agents, topoisomerase II inhibitors and platinum derivatives. It works primarily through topoisomerase I inhibition. Of note, Nemorubicin is active in cells with upregulation of the nucleotide excision repair (NER) pathway, where current therapies fail. Nemorubicin is biotransformed in the liver into cytotoxic metabolites that may further contribute to render this drug highly active against primary liver tumors or liver metastases.