Population pharmacokinetics of liposomal amphotericin B in adults with HIV-associated cryptococcal meningoencephalitis

Evolution of Laboratory Diagnostics for Cryptococcosis and Missing Links to Optimize Diagnosis and Outcomes in Resource-Constrained Settings

Cryptococcal meningitis is one of the leading causes of death in sub-Saharan Africa among patients with advanced HIV disease. Early diagnosis is crucial in improving treatment outcomes. Despite advances and the availability of modern and point-of-care diagnostics for cryptococcosis, gaps still exist in resource-constrained settings, leading to unfavorable treatment outcomes. Here, we review the current outstanding issues or missing links that need to be filled to optimize the diagnosis of cryptococcosis in resource-constrained settings to improve treatment outcomes. We highlight the evolution of cryptococcosis diagnostics; the roles of early fungicidal activity, cryptococcal antigen titers, antifungal susceptibility testing, and therapeutic drug monitoring; and the missing links to optimize diagnosis and outcomes, including practical recommendations.

Integration of genomic and pharmacokinetic data to predict clinical outcomes in HIV-associated cryptococcal meningitis

Cryptococcal meningitis causes an estimated 112,000 global deaths per annum. Genomic and phenotypic features of the infecting strain of Cryptococcus spp. have been associated with outcomes from cryptococcal meningitis. Additionally, population-level pharmacokinetic variability is well documented in these patient cohorts. The relative contribution of these factors to clinical outcomes is unknown. Based in Malawi, we conducted a sub-study of the phase 3 Ambition-CM trial (ISRCTN72509687), collecting plasma and cerebrospinal fluid at serial time points during the first 14 days of antifungal therapy. We explored the relative contribution of pathogen genotype, drug resistance phenotype, and pharmacokinetics on clinical outcomes including lumbar opening pressure, pharmacodynamic effect, and mortality. We report remarkable genomic homogeneity among infecting strains of Cryptococcus spp., within and between patients. There was no evidence of acquisition of antifungal resistance in our isolates. Genotypic features of the infecting strain were not consistently associated with adverse or favorable clinical outcomes. However, baseline fungal burden and early fungicidal activity (EFA) were associated with mortality. The strongest predictor of EFA was the level of exposure to amphotericin B. Our analysis suggests the most effective means of improving clinical outcomes from HIV-associated cryptococcal meningitis is to optimize exposure to potent antifungal therapy.

IMPORTANCE

HIV-associated cryptococcal meningitis is associated with a high burden of mortality. Research into the different strain types causing this disease has yielded inconsistent findings in terms of which strains are associated with worse clinical outcomes. Our study suggests that the exposure of patients to potent anti-cryptococcal drugs has a more significant impact on clinical outcomes than the strain type of the infecting organism. Future research should focus on optimizing drug exposure, particularly in the context of novel anticryptococcal drugs coming into clinical use.