A strong neutrophil response and fever may contribute to or be a result of (immuno)pathology in TBM. Aggressive fever control might improve outcome, and more-precise characterization of CSF leukocytes could guide possible host-directed therapeutic strategies in TBM.
High doses of rifampin may help patients with tuberculous meningitis (TBM) to survive. Pharmacokinetic pharmacodynamic evaluations suggested that rifampin doses higher than 13 mg/kg given intravenously or 20 mg/kg given orally (as previously studied) are warranted to maximize treatment response. In a double-blind, randomized, placebo-controlled phase II trial, we assigned 60 adult TBM patients in Bandung, Indonesia, to standard 450 mg, 900 mg, or 1,350 mg (10, 20, and 30 mg/kg) oral rifampin combined with other TB drugs for 30 days. The endpoints included pharmacokinetic measures, adverse events, and survival. A double and triple dose of oral rifampin led to 3- and 5-fold higher geometric mean total exposures in plasma in the critical early days (2 ± 1) of treatment (area under the concentration-time curve from 0 to 24 h [AUC], 53.5 mg · h/liter versus 170.6 mg · h/liter and 293.5 mg · h/liter, respectively; < 0.001), with proportional increases in cerebrospinal fluid (CSF) concentrations and without an increase in the incidence of grade 3 or 4 adverse events. The 6-month mortality was 7/20 (35%), 9/20 (45%), and 3/20 (15%) in the 10-, 20-, and 30-mg/kg groups, respectively ( = 0.12). A tripling of the standard dose caused a large increase in rifampin exposure in plasma and CSF and was safe. The survival benefit with this dose should now be evaluated in a larger phase III clinical trial. (This study has been registered at ClinicalTrials.gov under identifier NCT02169882.).
Background
Intensified antimicrobial treatment with higher rifampicin doses may improve outcome of tuberculous meningitis, but the desirable exposure and necessary dose are unknown. Our objective was to characterize the relationship between rifampicin exposures and mortality in order to identify optimal dosing for tuberculous meningitis.
Methods
An individual patient meta-analysis was performed on data from three Indonesian randomized controlled phase II trials comparing oral rifampicin 450mg (~10mg/kg) to intensified regimens including 750-1350mg orally, or a 600mg intravenous infusion. Pharmacokinetic data from plasma and CSF was analyzed with nonlinear mixed-effects modeling. Six-month survival was described with parametric time-to-event models.
Results
Pharmacokinetic analyses included 133 individuals (1150 concentration measurements, 170 from CSF). The final model featured two disposition-compartments, saturable clearance and autoinduction. Rifampicin CSF concentrations were described by a partition coefficient (5.5% [95%CI 4.4-6.4]) and half-life for distribution plasma to CSF (2.1 h [1.3-2.9]). Higher CSF protein concentration increased the partition coefficient. Survival of 148 individuals (58 died, 15 drop-outs) was well described by an exponentially declining hazard, with lower age, higher baseline Glasgow Coma Scale score and higher individual rifampicin plasma exposure reducing the hazard. Simulations predicted an increase in 6-month survival from ~50% to ~70% upon increasing the oral rifampicin dose from 10 to 30mg/kg, and that higher doses would further increase survival.
Conclusions
Higher rifampicin exposure substantially decreased the risk of death, and the maximal effect was not reached within the studied range. We suggest a rifampicin dose of at least 30mg/kg to be investigated in phase III clinical trials.
Modified ZN stain does not improve diagnosis of TBM. Currently available tests are insensitive, but testing large CSF volumes improves performance. New diagnostic tests for TBM are urgently required.
IntroductionPrevious studies, mostly from Africa, have shown that serum cryptococcal antigenemia may precede the development of cryptococcal meningitis and early death among patients with advanced HIV infection. We examined cryptococcal antigenemia as a risk factor for HIV-associated mortality in Indonesia, which is experiencing a rapidly growing HIV epidemic.MethodsWe included ART-naïve HIV patients with a CD4 cell count below 100 cells/μL and no signs of meningitis in an outpatient HIV clinic in Bandung, West Java, Indonesia. Baseline clinical data and follow-up were retrieved from a prospective database, and cryptococcal antigen was measured in stored serum samples using a semiquantitative lateral flow assay. Cox regression analysis was used to identify factors related to mortality.ResultsAmong 810 patients (median CD4 cell count 22), 58 (7.1%) had a positive cryptococcal antigen test with a median titre of 1:80 (range: 1:1 to 1:2560). Cryptococcal antigenemia at baseline was strongly associated with the development of cryptococcal meningitis and early death and loss to follow-up. After one year, both death (22.4% vs. 11.6%; p=0.016; adjusted HR 2.19; 95% CI 1.78–4.06) and the combined endpoint of death or loss to follow-up (67.2% vs. 40.4%; p<0.001; adjusted HR 1.57; 95% CI 1.12–2.20) were significantly higher among patients with a positive cryptococcal antigen test.ConclusionsCryptococcal antigenemia is common and clinically relevant among patients with advanced HIV in this setting. Routine screening for cryptococcal antigen followed by lumbar puncture and pre-emptive antifungal treatment for those who are positive may help in reducing early mortality.
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