Standards for clinical trials for treating TB.

BACKGROUND: The value, speed of completion and robustness of the evidence generated by TB treatment trials could be improved by implementing standards for best practice.METHODS: A global panel of experts participated in a Delphi process, using a 7-point Likert scale to score and revise draft standards until consensus was reached.RESULTS: Eleven standards were defined: Standard 1, high quality data on TB regimens are essential to inform clinical and programmatic management; Standard 2, the research questions addressed by TB trials should be relevant to affected communities, who should be included in all trial stages; Standard 3, trials should make every effort to be as inclusive as possible; Standard 4, the most efficient trial designs should be considered to improve the evidence base as quickly and cost effectively as possible, without compromising quality; Standard 5, trial governance should be in line with accepted good clinical practice; Standard 6, trials should investigate and report strategies that promote optimal engagement in care; Standard 7, where possible, TB trials should include pharmacokinetic and pharmacodynamic components; Standard 8, outcomes should include frequency of disease recurrence and post-treatment sequelae; Standard 9, TB trials should aim to harmonise key outcomes and data structures across studies; Standard 10, TB trials should include biobanking; Standard 11, treatment trials should invest in capacity strengthening of local trial and TB programme staff.CONCLUSION: These standards should improve the efficiency and effectiveness of evidence generation, as well as the translation of research into policy and practice.

TB therapeutic drug monitoring - analysis of opportunities in Romania and Ukraine.

INTRODUCTION: Therapeutic drug monitoring (TDM) could improve TB treatment outcomes by avoiding drug toxicity or underdosing. In this study, we describe the patient burden in three TB centres in Romania and Ukraine with a TDM indication, as per the current guidelines, in order to estimate the feasibility of implementing TDM.METHODS: A retrospective multi-centre study was conducted at the Iasi Lung Hospital (Iasi, Romania), Bucharest Marius Nasta Institute (Bucharest, Romania) and Chernivtsi TB Centre (Chernivtsi, Ukraine) in adult hospitalised TB patients.RESULTS: A total of 927 participants were admitted, of whom 37.8% had at least one indication for TDM, the most frequent being slow response to TB treatment (202/345, 58.6%); 55.5% had at least one cavity present on chest X-ray. Patients with a TDM indication stayed in the hospital for a median of 67 days and took on average 2 months more to reach a successful TB outcome.CONCLUSION: TDM could be a valuable tool to improve management of selected TB patients. The decision on whether to perform TDM is often delayed by 2 months due to waiting for culture results after treatment initiation. A randomised control trial should be performed in order to define TDM's precise role in TB therapy.

Population Pharmacokinetic Model and Optimal Sampling Strategies for Micafungin in Critically Ill Patients Diagnosed with Invasive Candidiasis.

Candida bloodstream infections are associated with high attributable mortality, where early initiation of adequate antifungal therapy is important to increase survival in critically ill patients. The exposure variability of micafungin, a first-line agent used for the treatment of invasive candidiasis, in critically ill patients is significant, potentially resulting in underexposure in a substantial portion of these patients. The objective of this study was to develop a population pharmacokinetic model including appropriate sampling strategies for assessing micafungin drug exposure in critically ill patients to support adequate area under the concentration-time curve (AUC) determination. A two-compartment pharmacokinetic model was developed using data from intensive care unit (ICU) patients (n = 19), with the following parameters: total body clearance (CL), volume of distribution of the central compartment (V1), inter-compartmental clearance (CL12), and volume of distribution of the peripheral compartment (V2). The final model was evaluated with bootstrap analysis and the goodness-of-fit plots for the population and individual predicted micafungin plasma concentrations. Optimal sampling strategies (with sampling every hour, 24 h per day) were developed with 1- and 2-point sampling schemes. Final model parameters (±SD) were: CL = 1.03 (0.37) (L/h/1.85 m2), V1 = 0.17 (0.07) (L/kg LBMc), CL12 = 1.80 (4.07) (L/h/1.85 m2), and V2 = 0.12 (0.06) (L/kg LBMc). Sampling strategies with acceptable accuracy and precision were developed to determine the micafungin AUC. The developed model with optimal sampling procedures provides the opportunity to achieve quick optimization of the micafungin exposure from a single blood sample using Bayesian software and may be helpful in guiding early dose decision-making.

Clinical standards for drug-susceptible pulmonary TB.

BACKGROUND: The aim of these clinical standards is to provide guidance on 'best practice´ for diagnosis, treatment and management of drug-susceptible pulmonary TB (PTB).METHODS: A panel of 54 global experts in the field of TB care, public health, microbiology, and pharmacology were identified; 46 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all 46 participants.RESULTS: Seven clinical standards were defined: Standard 1, all patients (adult or child) who have symptoms and signs compatible with PTB should undergo investigations to reach a diagnosis; Standard 2, adequate bacteriological tests should be conducted to exclude drug-resistant TB; Standard 3, an appropriate regimen recommended by WHO and national guidelines for the treatment of PTB should be identified; Standard 4, health education and counselling should be provided for each patient starting treatment; Standard 5, treatment monitoring should be conducted to assess adherence, follow patient progress, identify and manage adverse events, and detect development of resistance; Standard 6, a recommended series of patient examinations should be performed at the end of treatment; Standard 7, necessary public health actions should be conducted for each patient. We also identified priorities for future research into PTB.CONCLUSION: These consensus-based clinical standards will help to improve patient care by guiding clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment for PTB.

Clinical standards for the dosing and management of TB drugs.

BACKGROUND: Optimal drug dosing is important to ensure adequate response to treatment, prevent development of drug resistance and reduce drug toxicity. The aim of these clinical standards is to provide guidance on 'best practice´ for dosing and management of TB drugs.METHODS: A panel of 57 global experts in the fields of microbiology, pharmacology and TB care were identified; 51 participated in a Delphi process. A 5-point Likert scale was used to score draft standards. The final document represents the broad consensus and was approved by all participants.RESULTS: Six clinical standards were defined: Standard 1, defining the most appropriate initial dose for TB treatment; Standard 2, identifying patients who may be at risk of sub-optimal drug exposure; Standard 3, identifying patients at risk of developing drug-related toxicity and how best to manage this risk; Standard 4, identifying patients who can benefit from therapeutic drug monitoring (TDM); Standard 5, highlighting education and counselling that should be provided to people initiating TB treatment; and Standard 6, providing essential education for healthcare professionals. In addition, consensus research priorities were identified.CONCLUSION: This is the first consensus-based Clinical Standards for the dosing and management of TB drugs to guide clinicians and programme managers in planning and implementation of locally appropriate measures for optimal person-centred treatment to improve patient care.

Optimization of Fluconazole Dosing for the Prevention and Treatment of Invasive Candidiasis Based on the Pharmacokinetics of Fluconazole in Critically Ill Patients.

The efficacy of fluconazole is related to the area under the plasma concentration-time curve (AUC) over the MIC of the microorganism. Physiological changes in critically ill patients may affect the exposure of fluconazole, and therefore dosing adjustments might be needed. The aim of this study was to evaluate variability in fluconazole drug concentration in intensive care unit (ICU) patients and to develop a pharmacokinetic model to support personalized fluconazole dosing. A prospective observational pharmacokinetic study was performed in critically ill patients receiving fluconazole either as prophylaxis or as treatment. The association between fluconazole exposure and patient variables was studied. Pharmacokinetic modeling was performed with a nonparametric adaptive grid (NPAG) algorithm using R package Pmetrics. Data from 33 patients were available for pharmacokinetic analysis. Patients on dialysis and solid organ transplant patients had a significantly lower exposure to fluconazole. The population was best described with a one-compartment model, where the mean volume of distribution was 51.52 liters (standard deviation [SD], 19.81) and the mean clearance was 0.767 liters/h (SD, 0.46). Creatinine clearance was tested as a potential covariate in the model, but was not included in the final population model. A significant positive correlation was found between the fluconazole exposure (AUC) and the trough concentration (Cmin). Substantial variability in fluconazole plasma concentrations in critically ill adults was observed, where the majority of patients were underexposed. Fluconazole Cmin therapeutic drug monitoring (TDM)-guided dosing can be used to optimize therapy in critically ill patients. (This study has been registered at ClinicalTrials.gov under identifier NCT02491151.).

Clinical and economic impact of medication non-adherence in drug-susceptible tuberculosis: a systematic review.

BACKGROUND: Despite considerable efforts to globally eradicate TB, and the availability of effective antibiotics, TB elimination goals are falling behind. While non-adherence to TB drug regimens may compromise effective treatment, its full impact is still unknown.OBJECTIVE: To determine the clinical and economic impact of non-adherence to TB medication on treatment outcomes in drug-susceptible TB patients (DS-TB).METHODS: A systematic review was performed using PubMed and Embase for studies published between 2009 and 2019 reporting associations between adherence and WHO-defined TB treatment outcomes and economic outcomes in DS-TB patients.RESULTS: A total of 14 studies were included. Eight focused on the association between non-adherence and death, 2 on treatment failure, 1 study on successful treatment outcome, 1 study on both successful and unsuccessful treatment outcomes and 2 on cost outcomes. Most studies (71.4%) were retrospective cohort or case-control studies. The results showed that non-adherence to TB drug regimens was associated with death, treatment failure and lower cure rates.CONCLUSION: Non-adherence to TB drugs has a profound impact on both clinical and economic TB outcomes. To reach WHO TB elimination goals, preventing non-adherence and the implementation of cost-effective intervention programmes should receive the highest priority.

How to design a study to evaluate therapeutic drug monitoring in infectious diseases?

BACKGROUND: Therapeutic drug monitoring (TDM) is a tool to personalize and optimize dosing by measuring the drug concentration and subsequently adjusting the dose to reach a target concentration or exposure. The evidence to support TDM is however often ranked as expert opinion. Limitations in study design and sample size have hampered definitive conclusions of the potential added value of TDM. OBJECTIVES: We aim to give expert opinion and discuss the main points and limitations of available data from antibiotic TDM trials and emphasize key elements for consideration in design of future clinical studies to quantify the benefits of TDM. SOURCES: The sources were peer-reviewed publications, guidelines and expert opinions from the field of TDM. CONTENT: This review focuses on key aspects of antimicrobial TDM study design: describing the rationale for a TDM study, assessing the exposure of a drug, assessing susceptibility of pathogens and selecting appropriate clinical endpoints. Moreover we provide guidance on appropriate study design. IMPLICATIONS: This is an overview of different aspects relevant for the conduct of a TDM study. We believe that this paper will help researchers and clinicians to design and conduct high-quality TDM studies.

Management of patients with multidrug-resistant tuberculosis.

The emergence of multidrug-resistant tuberculosis (MDR-TB; defined as resistance to at least rifampicin and isoniazid) represents a growing threat to public health and economic growth. Never before in the history of mankind have more patients been affected by MDR-TB than is the case today. The World Health Organization reports that MDR-TB outcomes are poor despite staggeringly high management costs. Moreover, treatment is prolonged, adverse events are common, and the majority of affected patients do not receive adequate treatment. As MDR-TB strains are often resistant to one or more second-line anti-TB drugs, in-depth genotypic and phenotypic drug susceptibility testing is needed to construct personalised treatment regimens to improve treatment outcomes. For the first time in decades, the availability of novel drugs such as bedaquiline allow us to design potent and well-tolerated personalised MDR-TB treatment regimens based solely on oral drugs. In this article, we present management guidance to optimise the diagnosis, algorithm-based treatment, drug dosing and therapeutic drug monitoring, and the management of adverse events and comorbidities, associated with MDR-TB. We also discuss the role of surgery, physiotherapy, rehabilitation, palliative care and smoking cessation in patients with MDR-TB. We hope that incorporating these recommendations into patient care will be helpful in optimising treatment outcomes, and lead to more MDR-TB patients achieving a relapse-free cure.

The Role of Fluoroquinolones in the Treatment of Tuberculosis in 2019.

The inability to use powerful antituberculosis drugs in an increasing number of patients seems to be the biggest threat towards global tuberculosis (TB) elimination. Simplified, shorter and preferably less toxic drug regimens are being investigated for pulmonary TB to counteract emergence of drug resistance. Intensified regimens with high-dose anti-TB drugs during the first weeks of treatment are being investigated for TB meningitis to increase the survival rate among these patients. Moxifloxacin, gatifloxacin and levofloxacin are seen as core agents in case of resistance or intolerance against first-line anti-TB drugs. However, based on their pharmacokinetics (PK) and pharmacodynamics (PD), these drugs are also promising for TB meningitis and might perhaps have the potential to shorten pulmonary TB treatment if dosing could be optimized. We prepared a comprehensive summary of clinical trials investigating the outcome of TB regimens based on moxifloxacin, gatifloxacin and levofloxacin in recent years. In the majority of clinical trials, treatment success was not in favour of these drugs compared to standard regimens. By discussing these results, we propose that incorporation of extended PK/PD analysis into the armamentarium of drug-development tools is needed to clarify the role of moxifloxacin, gatifloxacin and levofloxacin for TB, using the right dose. In addition, to prevent failure of treatment or emergence of drug-resistance, PK and PD variability advocates for concentration-guided dosing in patients at risk for too low a drug-exposure.