Precision-Enhancing Risk Stratification Tools for Selecting Optimal Treatment Durations in Tuberculosis Clinical Trials.

Rationale: No evidence-based tools exist to enhance precision in the selection of patient-specific optimal treatment durations to study in tuberculosis clinical trials. Objectives: To develop risk stratification tools that assign patients with tuberculosis into risk groups of unfavorable outcome and inform selection of optimal treatment duration for each patient strata to study in clinical trials. Methods: Publicly available data from four phase 3 trials, each evaluating treatment duration shortening from 6 to 4 months, were used to develop parametric time-to-event models that describe unfavorable outcomes. Regimen, baseline, and on-treatment characteristics were evaluated as predictors of outcomes. Exact regression coefficients of predictors were used to assign risk groups and predict optimal treatment durations. Measurements and Main Results: The parametric model had an area under the receiver operating characteristic curve of 0.72. A six-item risk score (HIV status, smear grade, sex, cavitary disease status, body mass index, and Month 2 culture status) successfully grouped participants into low (1,060/3,791; 28%), moderate (1,740/3,791; 46%), and high (991/3,791; 26%) risk, requiring treatment durations of 4, 6, and greater than 6 months, respectively, to reach a target cure rate of 93% when receiving standard-dose rifamycin-containing regimens. With current one-duration-fits-all approaches, high-risk groups have a 3.7-fold (95% confidence interval, 2.7-5.1) and 2.4-fold (1.9-2.9) higher hazard risk of unfavorable outcomes compared with low- and moderate-risk groups, respectively. Four-month regimens were noninferior to the standard 6-month regimen in the low-risk group. Conclusions: Our model discrimination was modest but consistent with current models of unfavorable outcomes. Our results showed that stratified medicine approaches are feasible and may achieve high cure rates in all patients with tuberculosis. An interactive risk stratification tool is provided to facilitate decision-making in the regimen development pathway.

Quality assurance in anti-tuberculosis drug procurement by the Stop TB Partnership-Global Drug Facility: Procedures, costs, time requirements, and comparison of assay and dissolution results by manufacturers and by external analysis.

BACKGROUND: Quality-assured medicines are a principal means of achieving health-related Sustainable Development Goals. An example of quality assurance/quality control (QA/QC) procedures in drug procurement is provided by the operation of the Global Drug Facility (GDF) of the Stop TB Partnership, the largest provider of tuberculosis (TB) medicines to the public sector worldwide. METHODS: Procedures and results of GDF's quality assurance/quality control (QA/QC) over the five-year period 2013-2017 were analysed retrospectively. 13,999 batches of 51 different medicines had been procured and reviewed within this period. 1,388 of these batches had been analysed in the laboratories of GDF's external quality control agent (QCA). Assay and dissolution results determined by the manufacturers and by the external QCA were compared using Bland-Altman analysis. RESULTS: All investigated batches of medicines were in specifications at the time of shipment. The costs for QA/QC were 0.8% of purchase costs. The median time required for chemical analysis was 10 working days. Comparison of the medicine quality analysis results showed for the poorly water-soluble compound rifampicin a bias of 4.4%, with the manufacturers reporting higher values than the external QCA, most likely due to different methods employed for the analysis. Overall 95% limits of agreement (LOAs) were -6.7 to +8.0% for assay, and -10.1 to +11.8% for dissolution. In case of kanamycin injections, 95% LOAs for assay reached -14.5 to +13.2%, largely attributable to samples from one manufacturer who had used a microbiological assay while the external QCA had used an HPLC assay. CONCLUSIONS: GDF's procedures represent a useful benchmark when evaluating QA/QC procedures of other medicine procurement operations. Inter-laboratory comparison using Bland-Altman plots allows to investigate bias and variability in medicine quality control and should be considered as a routine procedure by drug procurement agencies, to identify priorities for further improvements.

The Roll-out of Child-friendly Fixed-dose Combination TB Formulations in High-TB-Burden Countries: A Case Study of STEP-TB.

Childhood tuberculosis (TB) has hitherto been treated through estimation of pediatric doses through the crushing of adult pills, but the bitter taste of the pills and the inaccuracy of this dosing method presents a challenge for both patients and healthcare providers, leading to poor treatment outcomes. The TB Alliance therefore launched the Speeding Treatments to End Pediatric-Tuberculosis (STEP-TB) project to incentivize the introduction of pediatric Fixed-Dose Combinations (FDCs) of TB drugs. This case study describes the elements of this project, evaluates its impact, and highlights future challenges for pediatric TB treatment. The impact assessment incorporates both market impact as well as projected public health impact, evaluating the availability, affordability, and quality of the FDCs, and lastly providing a projection of lives saved as a result of scale-up of the FDCs to near-universal availability and utilization, based on a publicly available pediatric TB-specific model. STEP-TB resulted in the development of two child-friendly FDCs that were successfully brought to market and made available in 20 of the project's 22 high-burden countries. On the basis of a country-specific projection of pediatric TB mortality in Kenya, scale-up to near-universal availability and utilization of the new FDCs could reduce pediatric TB-associated mortality by 2660 cases over the next 5 years. Future challenges include maintaining affordable prices for the FDCs and considering mechanisms to incentivize their introduction among high-risk groups in low-burden countries.

Quality assurance of rifampicin-containing fixed-drug combinations in South Africa: dosing implications.

SETTING: Rifampicin (RMP) drives treatment response in drug-susceptible tuberculosis. Low RMP concentrations increase the risk of poor outcomes, and drug quality needs to be excluded as a contributor to low RMP exposure. OBJECTIVES AND DESIGN: We performed an open-label, three-way cross-over study of three licensed RMP-containing formulations widely used in South Africa to evaluate the bioavailability of RMP in a two-drug fixed-dose combination tablet (2FDC) and a four-drug FDC (4FDC) against a single-drug reference. RMP dosed at 600 mg was administered 2 weeks apart in random sequence. Plasma RMP concentrations were measured pre-dose and 1, 2, 3, 4, 6, 8 and 12 h post-dose. The area under the concentration-time curve (AUC0-12) of the FDCs was compared to the single drug reference. Simulations were used to predict the impact of our findings. RESULTS: Twenty healthy volunteers (median age 22.8 years, body mass index 24.2 kg/m2) completed the study. The AUC0-12 of the 4FDC/reference (geometric mean ratio [GMR] 78%, 90%CI 69-89) indicated an average 20% reduction in RMP bioavailability in the 4FDC. The 2FDC/reference (GMR 104%, 90%CI 97-111) was bioequivalent. Simulations suggested dose adjustments to compensate for the poor bioavailability of RMP with the 4FDC, and revised weight-band doses to prevent systematic underdosing of low-weight patients. CONCLUSION: Post-marketing surveillance of in vivo bioavailability of RMP and improved weight band-based dosing are recommended.

Assessment of the quality of anti-tuberculosis medicines in Almaty, Kazakhstan, 2014.

SETTING: In 2009, the World Health Organization (WHO) conducted a survey of the quality of four anti-tuberculosis drugs in the former Soviet Union countries. Kazakhstan had the highest proportion of substandard drugs. OBJECTIVE: To assess the quality of anti-tuberculosis drugs used in Kazakhstan in 2014. DESIGN: Fourteen anti-tuberculosis drugs from the Almaty Interdistrict TB Dispensary were randomly selected and screened for quality using Global Pharma Health Fund Minilab™ testing. First, the product and packaging were physically inspected to determine whether tablets/capsules were intact (i.e., whether they contained the full amount of the drug, and whether the packaging was genuine). Second, the tablets/capsules were dissolved in water to test whether they could be adequately absorbed by the body. Finally, semi-quantitive analyses were undertaken using thin-layer chromatography to verify the presence and concentration of the active pharmaceutical ingredient and to detect impurities. RESULTS: We discovered no counterfeit medicines. However, 163 (19%) of the 854 anti-tuberculosis drugs sampled failed at least one of the three tests. These samples were found among 24/50 (48%) batches of 14 anti-tuberculosis drugs. CONCLUSION: Our study identified a high proportion of poor-quality first- and second-line anti-tuberculosis drugs. Use of these medicines may lead to treatment failure and the development of drug resistance. Confirmatory testing should be performed to determine if they should be removed from the market.

Estimated generic prices for novel treatments for drug-resistant tuberculosis.

Background: The estimated worldwide annual incidence of MDR-TB is 480 000, representing 5% of TB incidence, but 20% of mortality. Multiple drugs have recently been developed or repurposed for the treatment of MDR-TB. Currently, treatment for MDR-TB costs thousands of dollars per course. Objectives: To estimate generic prices for novel TB drugs that would be achievable given large-scale competitive manufacture. Methods: Prices for linezolid, moxifloxacin and clofazimine were estimated based on per-kilogram prices of the active pharmaceutical ingredient (API). Other costs were added, including formulation, packaging and a profit margin. The projected costs for sutezolid were estimated to be equivalent to those for linezolid, based on chemical similarity. Generic prices for bedaquiline, delamanid and pretomanid were estimated by assessing routes of synthesis, costs/kg of chemical reagents, routes of synthesis and per-step yields. Costing algorithms reflected variable regulatory requirements and efficiency of scale based on demand, and were validated by testing predictive ability against widely available TB medicines. Results: Estimated generic prices were US$8-$17/month for bedaquiline, $5-$16/month for delamanid, $11-$34/month for pretomanid, $4-$9/month for linezolid, $4-$9/month for sutezolid, $4-$11/month for clofazimine and $4-$8/month for moxifloxacin. The estimated generic prices were 87%-94% lower than the current lowest available prices for bedaquiline, 95%-98% for delamanid and 94%-97% for linezolid. Estimated generic prices were $168-$395 per course for the STREAM trial modified Bangladesh regimens (current costs $734-$1799), $53-$276 for pretomanid-based three-drug regimens and $238-$507 for a delamanid-based four-drug regimen. Conclusions: Competitive large-scale generic manufacture could allow supplies of treatment for 5-10 times more MDR-TB cases within current procurement budgets.

[Standard therapy of tuberculosis]. / Standardtherapie der Tuberkulose.

Based on the results of studies from the 1960s-1980s the current four drug combination therapy was established as standard or short course tuberculosis therapy worldwide. The regional epidemiology and the often unique conditions within a national health system create the need for specific adjustments. Over the last years these were realized by the German central committee against tuberculosis (DZK) in the recommendations for tuberculosis therapy. Because of the recent development of migration into Germany from countries with higher tuberculosis incidences an increase in tuberculosis cases is to be expected. The expected increase in tuberculosis cases will lead to more contact with tuberculosis patients even in the outpatient setting. New S2k guidelines guided by the Association of the Scientific Medical Societies in Germany (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften, AWMF) for the treatment of tuberculosis for children and adults are under development. Before the release of the comprehensive guidelines, practical evidence for the diagnosis and treatment of uncomplicated tuberculosis is summarized in this document to meet the challenges of the recent developments.

[Treatment of tuberculosis. Current standards]. / Therapie der Tuberkulose. Was ist gesichert?

The treatment of drug-sensitive tuberculosis consists of 2 months of isoniazid, rifampin, pyrazinamide and ethambutol, followed by 4 months of isoniazid and rifampin. These drugs are well tolerated and cure rate are above 95 %. In contrast the treatment of drug-resistent tuberculosis is difficult, mostly due to side effects of the drugs used under these circumstances. Therefore, any treatment of drug-resistant tuberculosis has to be done by experts.

Forecasting Accuracy of the Hollow Fiber Model of Tuberculosis for Clinical Therapeutic Outcomes.

BACKGROUND: The hollow fiber system model of tuberculosis (HFS-TB), in tandem with Monte Carlo experiments, represents a drug development tool (DDT) with the potential for use to develop tuberculosis treatment regimens. However, the predictive accuracy of the HFS-TB, or any other nonclinical DDT such as an animal model, has yet to be robustly evaluated. METHODS: To avoid hindsight bias, a literature search was performed to identify clinical studies published at least 6 months after HFS-TB experiments' quantitative predictions. Steps to minimize bias and for reporting systematic reviews were applied as outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. Publications were scored for quality of evidence. Accuracy was calculated using the mean absolute percentage error, then summated with weighting assigned by sample size and quality-of-evidence score. Given the lack of a gold-standard tuberculosis DDT, the forecasting accuracy of a completely unreliable tool was also calculated from 1000 simulated experiments for a random or "total guesswork" model. RESULTS: The quantitative forecasting accuracy (95% confidence interval [CI]) for the "total guesswork" model was 15.6% (95% CI, 8.7%-22.5%); bias was -0.1% (95% CI, -2.5% to 2.2%). Twenty clinical studies were published after HFS-TB experiments predicted optimal drug exposures and doses, susceptibility breakpoints, and optimal combination regimens. Based on these clinical studies, the predictive accuracy of the HFS-TB was 94.4% (95% CI, 84.3%-99.9%), and bias was 1.8% (95% CI, -13.7% to 6.2%). CONCLUSIONS: The HFS-TB model is highly accurate at forecasting optimal drug exposures, doses, and dosing schedules for use in the clinic.

Monitoring the quality of medicines: results from Africa, Asia, and South America.

Monitoring the quality of medicines plays a crucial role in an integrated medicines quality assurance system. In a publicly available medicines quality database (MQDB), the U.S. Pharmacopeial Convention (USP) reports results of data collected from medicines quality monitoring (MQM) activities spanning the period of 2003-2013 in 17 countries of Africa, Asia, and South America. The MQDB contains information on 15,063 samples collected and tested using Minilab® screening methods and/or pharmacopeial methods. Approximately 71% of the samples reported came from Asia, 23% from Africa, and 6% from South America. The samples collected and tested include mainly antibiotic, antimalarial, and antituberculosis medicines. A total of 848 samples, representing 5.6% of total samples, failed the quality test. The failure proportion per region was 11.5%, 10.4%, and 2.9% for South America, Africa, and Asia, respectively. Eighty-one counterfeit medicines were reported, 86.4% of which were found in Asia and 13.6% in Africa. Additional analysis of the data shows the distribution of poor-quality medicines per region and by therapeutic indication as well as possible trends of counterfeit medicines.

Estimation of content of anti-TB drugs supplied at centres of the Revised National TB Control Programme in Tamil Nadu, India.

OBJECTIVE: To determine the content of certain antituberculosis (TB) drugs supplied at TB treatment centres of the Revised National TB Control Programme (RNTCP) in the state of Tamil Nadu, India. METHODS: Eight districts across the state were selected, and the following drugs were collected from five settings (District TB centre, TB unit, designated microscopy centres, DOT providers) in each district: rifampicin (150 and 450 mg), isoniazid (300 mg), pyrazinamide (500 and 750 mg), ethambutol (400 and 600 mg), ethionamide (250 mg), levofloxacin (500 mg) and cycloserine (250 mg). A maximum of 10 tablets/capsules were collected from each setting. The drugs were coded prior to analysis. All drugs were assayed by validated spectrophotometric methods. The acceptable limits for drug content were taken as 90-110% of the stated content. RESULTS: More than 90% of tablets of rifampicin 450 mg, isoniazid 300 mg, pyrazinamide 500 and 750 mg, ethambutol 400 and 600 mg and ethionamide 250 mg were within acceptable limits. Eighty per cent of rifampicin 150 mg, 21% of cycloserine 250 mg and 87% of levofloxacin 500 mg were within acceptable limits. The mean cycloserine content was below the acceptable limit in all districts, the mean drug content being 200 mg (range: 108-245 mg). CONCLUSION: This systematic study showed that the stated drug content of cycloserine was not reached in all districts. Deterioration of cycloserine could be minimised by storing the drug in refrigerators. The geographical location of the districts had no influence on the drug content.

Paper analytical devices for fast field screening of beta lactam antibiotics and antituberculosis pharmaceuticals.

Reports of low-quality pharmaceuticals have been on the rise in the past decade, with the greatest prevalence of substandard medicines in developing countries, where lapses in manufacturing quality control or breaches in the supply chain allow substandard medicines to reach the marketplace. Here, we describe inexpensive test cards for fast field screening of pharmaceutical dosage forms containing beta lactam antibiotics or combinations of the four first-line antituberculosis (TB) drugs. The devices detect the active pharmaceutical ingredients (APIs) ampicillin, amoxicillin, rifampicin, isoniazid, ethambutol, and pyrazinamide and also screen for substitute pharmaceuticals, such as acetaminophen and chloroquine that may be found in counterfeit pharmaceuticals. The tests can detect binders and fillers such as chalk, talc, and starch not revealed by traditional chromatographic methods. These paper devices contain 12 lanes, separated by hydrophobic barriers, with different reagents deposited in the lanes. The user rubs some of the solid pharmaceutical across the lanes and dips the edge of the paper into water. As water climbs up the lanes by capillary action, it triggers a library of different chemical tests and a timer to indicate when the tests are completed. The reactions in each lane generate colors to form a "color bar code" which can be analyzed visually by comparison with standard outcomes. Although quantification of the APIs is poor compared with conventional analytical methods, the sensitivity and selectivity for the analytes is high enough to pick out suspicious formulations containing no API or a substitute API as well as formulations containing APIs that have been "cut" with inactive ingredients.

Engaging communities in tuberculosis research.

According to a growing consensus among biomedical researchers, community engagement can improve the ethics and outcomes of clinical trials. Although successful efforts to develop community engagement practices in HIV/AIDS research have been reported, little attention has been given to engagement with the community in tuberculosis research. This article aims to draw attention to some existing community engagement initiatives in tuberculosis research and to resources that might help tuberculosis researchers to establish and implement community engagement programmes for their trials. One of these resources-the good participatory practice guidelines for tuberculosis drug trials-offers a conceptual framework and practical guidance for community engagement in tuberculosis research. To build momentum and to improve community engagement, lessons need to be shared, and formal assessment strategies for community engagement initiatives need to be developed. To build successfully on the promising activities described in this personal view, research funders and sponsors should show leadership in allocation of resources for the implementation and assessment of community engagement programmes in tuberculosis trials.

Substandard and falsified anti-tuberculosis drugs: a preliminary field analysis.

SETTING: Pharmacies in 19 cities in Angola, Brazil, China, Democratic Republic of Congo, Egypt, Ethiopia, Ghana, India (n = 3), Kenya, Nigeria, Russia, Rwanda, Thailand, Turkey, Uganda, United Republic of Tanzania and Zambia. OBJECTIVE: To assess the quality of the two main first-line anti-tuberculosis medicines, isoniazid and rifampicin, procured from private-sector pharmacies, to determine if substandard and falsified medicines are available and if they potentially contribute to drug resistance in cities in low- and middle-income countries. DESIGN: Local nationals procured 713 treatment packs from a selection of pharmacies in 19 cities. These samples were tested for quality using 1) thin-layer chromatography to analyze levels of active pharmaceutical ingredient (API), and 2) disintegration testing. RESULTS: Of 713 samples tested, 9.1% failed basic quality testing for requisite levels of API or disintegration. The failure rate was 16.6% in Africa, 10.1% in India, and 3.9% in other middle-income countries. CONCLUSIONS: Substandard and falsified drugs are readily available in the private marketplace and probably contribute to anti-tuberculosis drug resistance in low- and middle-income countries. This issue warrants further investigation through large-scale studies of drug quality in all markets.

TB and MDR/XDR-TB in European Union and European Economic Area countries: managed or mismanaged?

In spite of the growing awareness of emerging drug-resistant Mycobacterium tuberculosis, the extent of inappropriate tuberculosis (TB) case management may be underestimated, even in Europe. We evaluated TB case management in the European Union/European Economic Area countries, with special focus on multidrug-resistant (MDR) and extensively drug-resistant (XDR)-TB, using a purposely developed, standardised survey tool. National reference centres in five countries representing different geographical, socioeconomic and epidemiological patterns of TB in Europe were surveyed. 40 consecutive, original clinical TB case records (30 MDR/XDR-TB cases) were reviewed in each of the five countries. The findings were recorded and, through the survey tool, compared with previously agreed and identified international standards. Deviations from international standards of TB care were observed in the following areas: surveillance (no information available on patient outcomes); infection control (lack of respiratory isolation rooms/procedures and negative-pressure ventilation rooms); clinical management of TB, MDR-TB and HIV co-infection (inadequate bacteriological diagnosis, regimen selection and treatment duration); laboratory support; and diagnostic/treatment algorithms. Gaps between present international standards of care and the management of MDR/XDR-TB patients were identified. Training, increased awareness, promotion of standards and allocation of appropriate resources are necessary to ensure appropriate care and management as well as to prevent further emergence of drug resistance.