RIFABUTIN FOR THE TREATMENT OF NEWLY-DIAGNOSED PULMONARY TUBERCULOSIS- A MULTINATIONAL, RANDOMIZED, COMPARATIVE-STUDY VERSUS RIFAMPICIN

Setting: Patients with newly-diagnosed drug-sensitive, radiographicall y active and bacteriologically confirmed pulmonary tuberculosis recrui ted at 6 centres in Argentina, Brazil and Thailand. Objective: To asse ss the efficacy, tolerability and toxicity of two regimens containing different daily dosages of rifabutin in comparison with rifampicin.Des ign: Multicentred, randomised, comparative study. In each group, study medications were administered daily for 6 months combined with isonia zid (6 months), and with pyrazinamide and ethambutol (both stopped aft er 2 months). Treatment success patients were followed-up for up to 2 years. Results: A total of 520 patients were enrolled and randomly ass igned to receive either rifampicin (n = 175), or rifabutin 150 mg (n = 174) or rifabutin 300 mg (n = 171). Considering all patients with pos itive baseline culture, the success rates at the last valid observatio n for each patient were 89%, 94% and 92% in the rifampicin, rifabutin 150 mg, and rifabutin 300 mg groups, respectively. The median time to culture conversion was comparable in the 3 groups and was 34 days for rifampicin and 37 days for each of the rifabutin groups. During the dr ug-free follow-up period, one relapse occurred in the rifampicin group , and two in each of the rifabutin groups. The 3 treatment schedules a ppeared well tolerated. No patients had to discontinue therapy because of an adverse event in the rifabutin 150 mg group, compared to one in the rifampicin and 5 in the rifabutin 300 mg group. Conclusion: All 3 regimens proved effective and well tolerated. Rifabutin at 150 mg/d s howed the best risk-to-benefit ratio, in that this group had the highe st proportion of patients completing treatment, the highest bacteriolo gical conversion rates and the lowest incidence of adverse events.