CHROMOMYCIN A 3 (TOYOMYCIN) AND RADIOTHERAPY IN THE TREATMENT OF ADVANCED MALIGNANCY

Since early in 1962 Chromomycin A 3 (Toyomycin) has been used in clinical trials for patients with advanced cancer at the Pretoria General Hospital. The results of our first experience with this anti·tumour antibiotic were reported in 1964.' The present report deals with the results obtained in 123 patients treated with this agent. Chromomycin A 3 is the most effective tumour-suppres­ sing part of chromomycin, an antibiotic discovered in a culture of Streplomyces griseus Nc. 7 by the Takeda Re­ search Laboratory in Japan.,·3 Chromomycin A 3, Mithra­ mycin and Olivomycin are three chemically related anti­ biotics. The latter two were discovered in the United States of America' and the Soviet Union' respectively. These substances are inactive against Gram·negative organisms, but inhibit the growth of Gram-positive organisms. Chromomycin A 3 inhibits RNA synthesis by the RNA polymerase, but only when the DNA template contains guanine 6 Goldberg,' of Harvard Medical School and Beth Israel Hospital, Boston, has done extensive studies on this and other actions of chromomycin, including those that show that Chromomycin A 3, Mithrarnycin and Olivomycin prcduce different spectra with DNA but only in the presence of a divalent cation. The magnitude of the change in the spectrum of chromomycin produced by DNA is a function of the Mg++ concentration.