Effect of Rifampicin on the Development of Tumours induced by Adenovirus in Male Hamsters

INITIAL in vitro studies established that rifampicin, one of a group of rifamycin SV derivatives^1,2, prohibits bacterial growth and phage replication by binding to a polypeptide component of the microbial DNA-dependent RNA polymerase^3–7. The trachoma agent and related psittacosis-lymphogranuloma agents are also inhibited in vitro and in embryonated eggs by this drug⁸. Further studies have shown that rifampicin is active against a number of bacteria in vivo, both after parenteral and oral administration^1,9,10. It also inhibits malaria in mice¹¹ and trachoma in monkeys^12,13 and is of special value in the treatment of human tuberculosis^14–16. The low toxicity of the rifamycins in mammals¹⁷ has been attributed to the observed relative insensitivity of mammalian RNA polymerase to the rifamycins in vitro^3,18.