In vitro and in vivo activities of new rifamycin derivatives against mycobacterial infections.

Several rifamycin derivatives have been developed during the last 15 years for the treatment of mycobacterial infections. For tuberculosis, rifabutin (RFB) showed strong activity and seemed to be suitable when tuberculosis patients were also treated for their AIDS infection. Rifapentine (RPT) was evaluated in patients with or without AIDS for its intermittent use. It displayed promising activity but must be strengthened in situations, such as AIDS or patients without AIDS but with cavities. Rifalazil (RLZ) has been evaluated in mice but the dosages used were much higher than those tolerated by patients. Regarding Mycobacterium avium infections, RFB showed significant prophylactic activity in humans, RPT displayed some activity in mice and RLZ showed modest activity in mice.