Two-stage activity-safety study of daily rifapentine during intensive phase treatment of pulmonary tuberculosis

BACKGROUND: Rifapentine (RPT) has potent activity against Mycobacterium tuberculosis; however, the optimal dose for anti-tuberculosis treatment is unknown. OBJECTIVE : To determine the antimicrobial activity, safety and tolerability of RPT 450 mg or 600 mg administered daily during the first 8 weeks of treatment for pulmonary tuberculosis (TB). DESIGN : In a two-stage, randomised open-label study, adults with sputum smear-positive TB were randomised to receive RPT 450 mg, RPT 600 mg or rifampicin (RMP) 600 mg daily for 8 weeks with isoniazid, pyrazinamide and ethambutol. The primary endpoint was sputum culture status on Löwenstein- Jensen (LJ) medium at completion of 8 weeks of treatment. RESULTS : A total of 153 participants were enrolled. Both RPTregimens met pre-specified criteria to advance to stage 2. At completion of 8 weeks of treatment, LJ culture conversion occurred in 85% (35/41), 96% (43/ 45) and 94% (34/36) of participants in the RPT 450 mg, RPT 600 mg and RMP groups, respectively. The proportions of participants discontinuing treatment were similar (respectively 1/54 [2.0%], 1/51 [2.0%] and 4/48 [8.3%] in the RPT 450 mg, RPT 600 mg and RMP groups), as were >grade 3 adverse events (0/54 [0%], 1/51 [2.0%] and 4/48 [8.3%]). CONCLUSIONS: There was a trend towards greater efficacy with RPT 600 mg than with RPT 450 mg. Daily RPT was safe and well-tolerated.