A semisynthetic analogue of the anthracycline antineoplastic antibiotic doxorubicin. Valrubicin exhibits antineoplastic properties through a variety of mechanisms. Similar to related anthracyclines antibiotics, valrubicin interacts with topoisomerase II, leading to inhibition of DNA replication and repair and RNA and protein synthesis. In addition, valrubicin accumulates in the cell cytoplasm where it inhibits protein kinase C (PKC). Valrubicin is less cardiotoxic than doxorubicin when administered systemically; applied topically, this agent shows excellent tissue penetration. (NCI04)