The use of rifabutin in Europe for the treatment of mycobacterial infection in AIDS patients.

The MICs of rifabutin on Mycobacterium avium are compatible with its efficacy in clinical infections. Two North American trials established the prophylactic effect of rifabutin in disseminated M. avium disease in AIDS patients. Several prospective non-randomized trials show the clinical and bacteriological efficacy of rifabutin. A large European study conducted from 1990 to 1993 randomized 382 patients, selected on a clinical basis, to receive a combination of ethambutol + clofazimine + isoniazid + placebo or rifabutin for 12 weeks. Of these, 200 were eligible, i.e. had a positive blood culture at day 0. The percentage of patients with fever decreased from 78% to 23% in the rifabutin arm and from 76% to 11% in the placebo group (difference statistically not significant). The percentage of positive blood cultures decreased from 100% to 70% and 29% in the placebo group and from 100% to 45% and 18% in the rifabutin group at weeks 0, 6 and 12 respectively. The rate of adverse events was 35% in the placebo and 30% in the rifabutin group (difference statistically not significant). Two other French randomized trials are being analysed: the first one compares a 14-day regimen of rifabutin to placebo. It shows a 70% success rate in the rifabutin arm and a 8% success rate in the control group. The second trial demonstrates that when given in addition to clarithromycin, unlike clofazimine a combination of rifabutin + ethambutol is effective in decreasing the relapse rate with acquired resistance to clarithromycin. After clarithromycin, rifabutin is the second drug which was proven to be active against disseminated M. avium disease in a controlled placebo trial.