Porfiromycin is an N-methyl derivative of the antineoplastic antibiotic mitomycin-C initially isolated from Streptomyces ardus. Upon administration, the drug undergoes chemical or enzymatic reduction, followed by spontaneous loss of the tertiary methoxy (hydroxyl) group and formation of an aromatic indole system. Thus activated, porfiromycin generates oxygen radicals and alkylates DNA, producing interstrand cross-links and single-strand breaks at guanosine residues. Porfiromycin was tested in phase III for head and neck carcinoma, however, its development was terminated.