A double-blinded randomised placebo-controlled phase II trial to evaluate high dose rifampicin for tuberculous meningitis: a dose finding study [Clinical Therapeutics]

High doses of rifampicin may help tuberculous meningitis (TBM) patients to survive. Pharmacokinetic-pharmacodynamic evaluations suggested that rifampicin doses higher than 13 mg/kg intravenously or 20 mg/kg orally (as previously studied) are warranted to maximize treatment response. In a double-blinded, randomised, placebo-controlled phase II trial, we assigned 60 adult TBM patients in Bandung, Indonesia, to standard 450 mg, 900 mg or 1350 mg (10, 20 and 30 mg/kg) oral rifampicin combined with other TB drugs for 30 days. Endpoints included pharmacokinetic measures, adverse events and survival. A double and triple dose of oral rifampicin led to three and five-fold higher geometric mean total exposures in plasma in the critical early days (2±1) of treatment (AUC_0-24h: 53·5 mg.h/L vs 170·6 mg.h/L vs. 293·5 mg.h/L, p<0·001), with proportional increases in CSF concentrations and without an increase in the incidence of grade 3/4 adverse events. Six-month mortality was 7/20 (35%), 9/20 (45%) and 3/20 (15%) in the 10, 20 and 30 mg/kg groups, respectively (p=0·12). Tripling the standard dose caused a large increase in rifampicin exposure in plasma and CSF and was safe. Survival benefit with this dose should now be evaluated in a larger phase III clinical trial.

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