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Background The WHO-endorsed shorter-course regimen for MDR-TB includes high-dose isoniazid. The pharmacokinetics of high-dose isoniazid within MDR-TB regimens has not been well described. Objectives To characterize isoniazid pharmacokinetics at 5–15 mg/kg as monotherapy or as part of the MDR-TB treatment regimen. Methods We used non-linear mixed-effects modelling to evaluate the combined data from INHindsight, a 7 day early bactericidal activity study with isoniazid monotherapy, and PODRtb, an observational study of patients on MDR-TB treatment including terizidone, pyrazinamide, moxifloxacin, kanamycin, ethionamide and/or isoniazid. Results A total of 58 and 103 participants from the INHindsight and PODRtb studies, respectively, were included in the analysis. A two-compartment model with hepatic elimination best described the data. N-acetyltransferase 2 (NAT2) genotype caused multi-modal clearance, and saturable first-pass was observed beyond 10 mg/kg dosing. Saturable isoniazid kinetics predicted an increased exposure of approximately 50% beyond linearity at 20 mg/kg dosing. Participants treated with the MDR-TB regimen had a 65.6% lower AUC compared with participants on monotherapy. Ethionamide co-administration was associated with a 29% increase in isoniazid AUC. Conclusions Markedly lower isoniazid exposures were observed in participants on combination MDR-TB treatment compared with monotherapy. Isoniazid displays saturable kinetics at doses >10 mg/kg. The safety implications of these phenomena remain unclear.

Rationale: There is accumulating evidence that higher-than-standard doses of isoniazid are effective against low-to-intermediate-level isoniazid-resistant strains of Mycobacterium tuberculosis, but...

Rationale: High-dose isoniazid is recommended in short-course regimens for multidrug-resistant tuberculosis (TB). The optimal dose of isoniazid and its individual contribution to efficacy against T...

The critical role of suppressive myeloid cells in immune regulation has come to the forefront in cancer research, with myeloid-derived suppressor cells (MDSCs) as a main oncology immunotherapeutic target. Recent improvement and standardization of criteria classifying tumor-induced MDSCs have led to unified descriptions and also promoted MDSC research in tuberculosis (TB) and AIDS. Despite convincing evidence on the induction of MDSCs by pathogen-derived molecules and inflammatory mediators in TB and AIDS, very little attention has been given to their therapeutic modulation or roles in vaccination in these diseases. Clinical manifestations in TB are consequences of complex host-pathogen interactions and are substantially affected by HIV infection. Here we summarize the current understanding and knowledge gaps regarding the role of MDSCs in HIV and Mycobacterium tuberculosis (co)infections. We discuss key scientific priorities to enable application of this knowledge to the development of novel strategies to improve vaccine efficacy and/or implementation of enhanced treatment approaches. Building on recent findings and potential for cross-fertilization between oncology and infection biology, we highlight current challenges and untapped opportunities for translating new advances in MDSC research into clinical applications for TB and AIDS.

The main advantage of animal models of infectious diseases over in vitro studies is the gain in the understanding of the complex dynamics between the immune system and the pathogen. While small animal models have practical advantages over large animal models, it is crucial to be aware of their limitations. Although the small animal model at least needs to be susceptible to the pathogen under study to obtain meaningful data, key elements of pathogenesis should also be reflected when compared to humans. Well-designed small animal models for HIV, hepatitis viruses and tuberculosis require, additionally, a thorough understanding of the similarities and differences in the immune responses between humans and small animals and should incorporate that knowledge into the goals of the study. To discuss these considerations, the NIAID hosted a workshop on ‘Small Animal Models for HIV, Hepatitis B, and Tuberculosis’ on May 30, 2019. Highlights of the workshop are outlined below.

Rationale: High-dose isoniazid is recommended in short-course regimens for multidrug-resistant tuberculosis (TB). The optimal dose of isoniazid and its individual contribution to efficacy against TB strains with inhA or katG mutations are unknown. Objectives: To define the optimal dose of isoniazid for patients with isoniazid-resistant TB mediated by inhA mutations. Methods: AIDS Clinical Trials Group A5312 is a phase 2A, open-label trial in which individuals with smear-positive pulmonary TB with isoniazid resistance mediated by an inhA mutation were randomized to receive isoniazid 5, 10, or 15 mg/kg daily for 7 days (inhA group), and control subjects with drug-sensitive TB received the standard dose (5 mg/kg/d). Overnight sputum cultures were collected daily. The 7-day early bactericidal activity (EBA) of isoniazid was estimated as the average daily change in log(10) cfu on solid media (EBA(cfu0–7)) or as time to positivity (TTP) in liquid media in hours (EBA(TTP0–7)) using nonlinear mixed-effects models. Measurements and Main Results: Fifty-nine participants (88% with cavitary disease, 20% HIV-positive, 16 with isoniazid-sensitive TB, and 43 with isoniazid-monoresistant or multidrug-resistant TB) were enrolled at one site in South Africa. The mean EBA(cfu0–7) at doses of 5, 10, and 15 mg/kg in the inhA group was 0.07, 0.17, and 0.22 log(10) cfu/ml/d, respectively, and 0.16 log(10) cfu/ml/d in control subjects. EBA(TTP0–7) patterns were similar. There were no drug-related grade ≥3 adverse events. Conclusions: Isoniazid 10–15 mg/kg daily had activity against TB strains with inhA mutations similar to that of 5 mg/kg against drug-sensitive strains. The activity of high-dose isoniazid against strains with katG mutations will be explored next. Clinical trial registered with www.clinicaltrials.gov (NCT01936831).

Summary Background Bedaquiline and delamanid are the first drugs of new classes registered for tuberculosis treatment in 40 years. Each can prolong the QTc interval, with maximum effects occurring weeks after drug initiation. The cardiac safety and microbiological activity of these drugs when co-administered are not well-established. Our aim was to characterise the effects of bedaquiline, delamanid, or both on the QTc interval, longitudinally over 6 months of multidrug treatment, among patients with multidrug-resistant or rifampicin-resistant tuberculosis taking multidrug background therapy. Methods ACTG A5343 is a phase 2, open-label, randomised, controlled trial in which adults with multidrug-resistant or rifampicin-resistant tuberculosis receiving multidrug background treatment were randomly assigned 1:1:1 by centrally, computer-generated randomisation, by means of permuted blocks to receive bedaquiline, delamanid, or both for 24 weeks. Participants were enrolled at TASK in Cape Town and the South African Tuberculosis Vaccine Initiative in Worcester, both in South Africa, and Hospital Maria Auxiliadora in Peru. Individuals with QTc greater than 450 ms were excluded. HIV-positive participants received dolutegravir-based antiretroviral therapy. Clofazimine was disallowed, and levofloxacin replaced moxifloxacin. ECG in triplicate and sputum cultures were done fortnightly. The primary endpoint was mean QTcF change from baseline (averaged over weeks 8–24); cumulative culture conversation at week 8-24 was an exploratory endpoint. Analyses included all participants who initiated study tuberculosis treatment (modified intention-to-treat population). This trial is registered with ClinicalTrials.gov , NCT02583048 and is ongoing. Findings Between Aug 26, 2016 and July 13, 2018, of 174 screened, 84 participants (28 in each treatment group, and 31 in total with HIV) were enrolled. Two participants did not initiate study treatment (one in the delamanid group withdrew consent and one in the bedaquiline plus delamanid group) did not meet the eligibility criterion). Mean change in QTc from baseline was 12·3 ms (95% CI 7·8–16·7; bedaquiline), 8·6 ms (4·0–13·1; delamanid), and 20·7 ms (16·1–25·3) (bedaquiline plus delamanid). There were no grade 3 or 4 adverse QTc prolongation events and no deaths during study treatment. Cumulative culture conversion by week 8 was 21 (88%) of 24 (95% CI 71–97; bedaquiline), 20 (83%) of 24 (65–95; delamanid), and 19 (95%) of 20 (79–100; bedaquiline plus delamanid) and was 92% (77–99) for bedaquiline, 91% (76–99), for delamanid, and 95% (79–100) for bedaquiline plus delamanid at 24 weeks. Interpretation Combining bedaquiline and delamanid has a modest, no more than additive, effect on the QTc interval, and initial microbiology data are encouraging. This study provides supportive evidence for use of these agents together in patients with multidrug-resistant or rifampicin-resistant tuberculosis with normal baseline QTc values. Funding Division of AIDS, National Institutes of Health.

Summary Background Clinical studies suggest that isoniazid contributes rapid bacterial killing during the initial 2 days of tuberculosis treatment, but that the activity of isoniazid declines substantially after day 3 of treatment. In this 14-day, phase 2a, open-label, randomised controlled trial we assessed whether isoniazid is essential in standard tuberculosis therapy. Methods The study took place at two clinical sites in the South African Western Cape region. Eligible individuals were adult (≥18 years of age) men and women with newly diagnosed, untreated, sputum smear-positive pulmonary tuberculosis. Participants who met the eligibility criteria were enrolled, and permuted block randomisation was used to assign participants to one of four treatment groups at a ratio of 1:1:1:1. All interventions occurred as variations of tuberculosis chemotherapy consisting of rifampicin (R), isoniazid (H), pyrazinamide (Z), ethambutol (E), and moxifloxacin (M) administered during study days 1–14 while participants were followed as inpatients. The HRZE1–2-RZE3–14 arm received isoniazid only on days 1 and 2; the HRZE1–2-MRZE3–14 arm received isoniazid on days 1 and 2 followed by the substitution of isoniazid for moxifloxacin on days 3–14; the RZE1–14 arm received no isoniazid; and the HRZE1–14 arm was the control group that received standard therapy of isoniazid for all 14 days. The primary endpoint was the daily decrease in log10-transformed colony-forming unit (CFU) counts per mL of sputum calculated by the multiple imputation method between baseline (day 0) and day 14 for all participants with at least one valid CFU count. This study is registered with ClinicalTrials.gov , NCT01589497 . Findings Of 89 patients screened, 69 were enrolled. 62 had at least one valid CFU count and were eligible for the primary endpoint analysis. The early bactericidal activity (EBA) over 14 days was 0·14 log10 units (95% CI 0·11–0·18) for participants receiving isoniazid for 2 days only (HRZE1–2-RZE3–14), 0·13 log10 units (0·09–0·17) for participants receiving isoniazid for 2 days followed by moxifloxacin (HRZE1–2-MRZE3–14), 0·12 log10 units (0·08–0·15) for those not receiving isoniazid (RZE1–14), and 0·13 log10 units (0·09–0·16) for those in the standard therapy group (HRZE1–14). Interpretation The EBA over 14 days for RZE was not significantly changed by the addition of isoniazid for the first 2 days or for the first 14 days of treatment. In a post-hoc analysis, significantly higher day 2 EBAs were observed for all groups among participants with higher baseline sputum CFU counts. Our finding that isoniazid does not contribute to EBA suggests that isoniazid could be replaced with another drug during standard treatment to improve efficacy and decrease rates of resistance to first-line drugs. Funding National Institute of Allergy and Infectious Diseases, National Institutes of Health, and AIDS Clinical Trials Group Statistical and Data Management Center.

Background With the second largest tuberculosis (TB) burden globally, China is committed to actively engage in international TB clinical trials to contribute to global TB research. However, lack of research capacity among local sites has been identified as a barrier. Main text The China Tuberculosis Clinical Trials Consortium (CTCTC) was initiated by Beijing Chest Hospital with investment from the US National Institutes of Health and technical support from Family Health International 360 in 2013, as a nationwide collaborative clinical trial network to strengthen selected clinical site research capacity and attract TB clinical trials. The program aims to: 1) recruit leading hospitals that care for TB patients; 2) conduct on-site assessment to identify capacity gaps and needs for improvement; 3) design and deliver capacity building activities; 4) attract and deliver high quality results for TB clinical trials. A total of 24 sites have joined CTCTC, covering 20 provinces in China. Twenty-two sites have been accredited by the National Medical Products Administration (NMPA) to be qualified to conduct TB clinical trials. The onsite assessment, extensive trainings among the CTCTC sites and young investigators have resulted in better understanding and improvement of the site capacity in conducting TB clinical trials. The establishment and growth of the CTCTC network has benefited from the good leadership, effective international cooperation and local commitment. Issues in human resources, regulatory environment and sustainability have been challenging the network from continuing growth. Clinical researchers have full-time clinical responsibilities in China and it is thus important to build a cadre of other human resources to assist. The regulatory environment is becoming friendlier in China to introduce international clinical trials to the CTCTC network. Conclusions The CTCTC, with mature management structure and sustainable development model, which are distilled five key lessons for other developing countries or investigators of interest. They are the respectively using assessment-based approach to design tailored training package, understanding the availability of clinical researchers, providing solutions to maintain sustainability, understanding local regulatory environments and working with an international organization with local on-site team, respectively. Although, the experiences and capacity of China’s TB hospitals in conducting clinical research vary. Considerable efforts to continue building the capacity are still needed, although the gap is smaller for a few top-tier hospitals.

Rationale: Recent studies suggest that baseline tuberculous sputum comprises a mixture of routinely culturable and differentially culturable tubercle bacteria (DCTB). The latter seems to be drug tolerant and dependent on resuscitation-promoting factors (Rpfs).Objectives: To further explore this, we assessed sputum from patients with tuberculosis for DCTB and studied the impact of exogenous culture filtrate (CF) supplementation ex vivo.Methods: Sputum samples from adults with tuberculosis and HIV-1 and adults with no HIV-1 were used for most probable number (MPN) assays supplemented with CF and Rpf-deficient CF, to detect CF-dependent and Rpf-independent DCTB, respectively.Measurements and Main Results: In 110 individuals, 19.1% harbored CF-dependent DCTB and no Rpf-independent DCTB. Furthermore, 11.8% yielded Rpf-independent DCTB with no CF-dependent DCTB. In addition, 53.6% displayed both CF-dependent and Rpf-independent DCTB, 1.8% carried CF-independent DCTB, and 13.6% had no DCTB. Sputum from individua...

China has been playing an increasingly important role in global health in recent decades. Substantial progress and reform has been made in the country's health care system, but China still hosts one third of the world's diabetes mellitus (DM) patients and one fifth of the world's tuberculosis (TB) patients. Recent economic and public health advancements have provided tools for new drug development and facilitated the implementation of novel strategies. However, a unique set of challenges exist, including regulatory barriers, ethical concerns and the lack of a unified system and approaches across disease areas. This article analyses the current disease situation in China and discusses China's potential role in the global battle against the TB and DM co-epidemic.

Tuberculous meningitis is a serious, life-threatening disease affecting vulnerable populations, including HIV-infected individuals and young children. The US National Institutes of Health convened a workshop to identify knowledge gaps in the molecular and immunopathogenic mechanisms of tuberculous meningitis and to develop a roadmap for basic and translational research that could guide clinical studies.

Children younger than 18 years account for a substantial proportion of patients with tuberculosis worldwide. Available treatments for paediatric drug-susceptible and drug-resistant tuberculosis, albeit generally effective, are hampered by high pill burden, long duration of treatment, coexistent toxic effects, and an overall scarcity of suitable child-friendly formulations. Several new drugs and regimens with promising activity against both drug-susceptible and drug-resistant strains have entered clinical development and are either in various phases of clinical investigation or have received marketing authorisation for adults; however, none have data on their use in children. This consensus statement, generated from an international panel of opinion leaders on childhood tuberculosis and incorporating reviews of published literature from January, 2004, to May, 2014, addressed four key questions: what drugs or regimens should be prioritised for clinical trials in children? Which populations of children are high priorities for study? When can phase 1 or 2 studies be initiated in children? What are the relevant elements of clinical trial design? The consensus panel found that children can be included in studies at the early phases of drug development and should be an integral part of the clinical development plan, rather than studied after regulatory approval in adults is obtained.

Improved treatments are needed for nearly all forms of Mycobacterium tuberculosis infection. Adjunctive host-directed therapies have the potential to shorten tuberculosis treatment duration, prevent resistance and reduce lung injury by promoting autophagy, antimicrobial peptide production and other macrophage effector mechanisms, as well as by modifying specific mechanisms that cause lung inflammation and matrix destruction. The range of candidates is broad, including several agents approved for other clinical indications that are ready for evaluation in Phase II clinical trials. The promise of new and existing host-directed therapies that could accelerate response and improve tuberculosis treatment outcomes is discussed in this Opinion article.

Tuberculosis (TB) is an ancient disease that is a devastating threat to public health. As the country with the second highest number of TB cases and the highest number of multidrug-resistant TB cases in the world, China is now striving to be at the forefront of TB research and drug development. This article is based on the observations made by the authors during the recent partnership initiative between the National Institutes of Health and the Chinese TB community, as well as an extensive literature review. The article examines the advantages and challenges of conducting large-scale international multicenter TB clinical trials in China. China is becoming an excellent location for new TB drug trials, especially in collaboration with international organizations that bring considerable technical assistance, quality control, training, and oversight with these partnerships.

To meet the challenges of increasing antimicrobial resistance, the infectious disease community needs innovative therapeutics. Precision medicine and immunotherapy are transforming cancer therapeutics by targeting the regulatory signaling pathways that are involved not only in malignancies, but also in the metabolic and immunologic function of the tumor microenvironment. Infectious diseases target many of the same regulatory pathways as they modulate host metabolic functions for their own nutritional requirements, and impede host immunity. These similarities and the advances made in precision medicine and immuno-oncology that are relevant for the current development of host-directed therapeutics (HDTs) to treat infectious diseases are discussed. To harness this potential, improvements in drug screening methods and development of assays that utilize the research tools including high through-put multiplexes already developed by oncology are essential. A multi-disciplinary approach that brings together immunologists, infectious disease specialists, and oncologists will be necessary to fully develop the potential of HDTs.

Reduction of active disease by preventive therapy has the potential to make an important contribution towards the goal of tuberculosis (TB) elimination. This report summarises discussions amongst a Working Group convened to consider areas of research that will be important in optimising the design and delivery of preventative therapies. The Working Group met in Cape Town on 26th February 2012, following presentation of results from the GC11 Grand Challenges in Global Health project to discover drugs for latent TB. (C) 2012 Elsevier Ltd. All rights reserved.

Item does not contain fulltext A growing number of new drugs for the treatment of tuberculosis are in clinical development. Confirmatory phase 3 trials are expensive and time-consuming and the question of whether one particular drug combination can be used to treat tuberculosis is less important from a public health perspective than the question of which are the shortest, simplest, most effective, and safest regimens. While preclinical and phase 1 studies provide some guidance in the selection of combinations for clinical evaluation, a large number of combinations will require phase 2 testing to ensure that only the best regimens advance to phase 3. The multi-arm multi-stage trial design is an example of a treatment selection-adaptive design where multiple experimental arms are each simultaneously compared with a common control and interim analyses allow for poor performing arms to be dropped early. Such designs, if designed and implemented correctly, require fewer patients, can be completed in a shorter time frame, and answer more relevant questions without any loss in statistical validity or scientific integrity. There are, however, practical issues that must be considered in applying this in tuberculosis treatment trials. More innovative trials designs should be considered to speed drug and regimen development for the treatment of tuberculosis.

Partially fueled by the human immunodeficiency virus (HIV) pandemic, tuberculosis is the second-leading cause of infectious diseases–associated mortality globally and the leading cause of death among those infected with HIV. In 2010, there were an estimated 8.8 million incident cases of tuberculosis and approximately 1.5 million deaths attributed to tuberculosis. Increased public heath efforts have been effective in decreasing the overall prevalence and mortality associated with this disease, but declines in incidence rates have been outpaced by global population growth, such that absolute incidence rates have not declined as fast as previously expected [1]. Commensurate with increased public recognition of the importance of tuberculosis to global health in the mid-1990s, biomedical research for tuberculosis has increased both in the United States and internationally. Although tools to conduct modern biomedical research involving tuberculosis have only been available for a little over a decade, this research has resulted in several successes, including promising new vaccines to protect against tuberculosis in the highest-risk populations, diagnostic candidates to improve the accuracy and speed of diagnosing all forms of tuberculosis, and new drug candidates with the potential for improved treatment and chemoprevention for drug-sensitive and drug-resistant tuberculosis. Despite these successes, many questions remain in all aspects of tuberculosis research, ranging from fundamental pathogenesis to programmatic implementation, and they are complicated by the complexity of the disease and its chronic nature. Compared with other infections, Mycobacterium tuberculosis infection does not elicit clinically relevant disease in the majority of subjects, and many who are infected carry asymptomatic, paucibacillary disease for decades. This complicates the definition and evaluation of early infection events and initial host responses and the characterization of infecting bacillary populations. The clinical definition of latent infection is limited to positive responses to injection of purified mycobacterial components (ie, the tuberculosis skin test) or to T-cell–recall responses measured through the production of interferon γ; unlike viral infections, latent tuberculous infections cannot be identified on the basis of stable antibody titers. Progression to active disease is not a clear unidirectional process and is prolonged, and many affected persons appear to be able to clear the infection, whereas others progress to active disease. The spectrum of active tuberculosis is complex. Although adult pulmonary tuberculosis is considered of greatest relevance for public health, extrapulmonary disease occurs in a significant portion of subjects, and pediatric manifestations of tuberculosis may be mistaken for other pulmonary infections and are difficult to diagnose. Treatment of active disease is complicated by the fact that the current standard of care involves combinations of drugs whose administration is sequenced on the basis of the clearance of mycobacteria from sputum and that, unlike most other antibacterial treatments, have to be administered for a minimum of 6 months to elicit a stable cure. Hypotheses exist that explain the need for such prolonged therapy, but they are difficult to test experimentally because initial treatment of tuberculosis eliminates bacteria from sputum and thus limits options for studying bacterial populations. Unlike many other infectious diseases, in tuberculosis, patients do not become immune to reinfection at a later time. Thus, a clear definition of the markers of immune protection is dependent on successful trials of new vaccines or has to be derived from data for persons who were infected but did not progress to active disease. However, both criteria are complicated by the limitations listed above. Comprehensive reviews of research priorities that have been defined on the basis of the unique nature of tuberculosis and the associated scientific/technical limitations of studying the disease have been addressed elsewhere [2–5], but several issues merit further exploration.

The lack of novel antimicrobial drugs in development for tuberculosis treatment has provided an impetus for the discovery of adjunctive host-directed therapies (HDTs). Several promising HDT candidates are being evaluated, but major advancement of tuberculosis HDTs will require understanding of the master or "core" cell signaling pathways that control intersecting immunologic and metabolic regulatory mechanisms, collectively described as "immunometabolism." Core regulatory pathways conserved in all eukaryotic cells include poly (ADP-ribose) polymerases (PARPs), sirtuins, AMP-activated protein kinase (AMPK), and mechanistic target of rapamycin (mTOR) signaling. Critical interactions of these signaling pathways with each other and their roles as master regulators of immunometabolic functions will be addressed, as well as how Mycobacterium tuberculosis is already known to influence various other cell signaling pathways interacting with them. Knowledge of these essential mechanisms of cell function regulation has led to breakthrough targeted treatment advances for many diseases, most prominently in oncology. Leveraging these exciting advances in precision medicine for the development of innovative next-generation HDTs may lead to entirely new paradigms for treatment and prevention of tuberculosis and other infectious diseases.

Rifapentine is a potent antituberculosis drug currently in phase III trials. Bioavailability decreases with increasing dose, yet high daily exposures are likely needed to improve efficacy and shorten the tuberculosis treatment duration. Further, the limits of tolerability are poorly defined. The phase I multicenter trial in healthy adults described here investigated two strategies to increase rifapentine exposures: dividing the dose or giving the drug with a high-fat meal. In arm 1, rifapentine was administered at 10 mg/kg of body weight twice daily and 20 mg/kg once daily, each for 14 days, separated by a 28-day washout; the dosing sequence was randomized. In arm 2, 15 mg/kg rifapentine once daily was given with a high-fat versus a low-fat breakfast. Sampling for pharmacokinetic analysis was performed on days 1 and 14. Population pharmacokinetic analyses were performed. This trial was stopped early for poor tolerability and because of safety concerns. Of 44 subjects, 20 discontinued prematurely; 11 of these discontinued for protocol-defined toxicity (a grade 3 or higher adverse event or grade 2 or higher rifamycin hypersensitivity). Taking rifapentine with a high-fat meal increased the median steady-state area under the concentration-time curve from time zero to 24 h (AUC 0–24ss ) by 31% (relative standard error, 6%) compared to that obtained when the drug was taken with a low-fat breakfast. Dividing the dose increased exposures substantially (e.g., 38% with 1,500 mg/day). AUC 0–24ss was uniformly higher in our study than in recent tuberculosis treatment trials, in which toxicity was rare. In conclusion, two strategies to increase rifapentine exposures, dividing the dose or giving it with a high-fat breakfast, successfully increased exposures, but toxicity was common in healthy adults. The limits of tolerability in patients with tuberculosis remain to be defined. (AIDS Clinical Trials Group study A5311 has been registered at ClinicalTrials.gov under registration no. NCT01574638.)

Background. In human immunodeficiency virus (HIV)–infected patients, fluconazole prophylaxis is associated with reductions in the rate of fungal infection. However, concerns exist with regard to the use of fluconazole prophylaxis and the risk of development of fluconazole treatment—refractory infections.Methods. We performed a randomized, open-label trial that compared oral fluconazole given continuously (200 mg 3 times weekly; the “continuous fluconazole arm”) with fluconazole that was provided only for episodes of orophayngeal candidiasis (OPC) or esophageal candidiasis (EC) (the “episodic fluconazole arm”) in HIV-infected persons with CD4 + T cell counts of

The pharmacokinetics of pyrazinamide (PZA) in patients with human immunodeficiency virus (HIV)-related tuberculosis are incompletely characterized. Serum PZA concentrations were determined at 2, 6, and 10 h after dosing in 48 subjects with HIV-related tuberculosis. Estimates of drug exposure using 2-h concentrations and 2- and 3-time point estimates of area under time-concentration curves (AUCs) were compared. For daily dosing, 2-h concentrations less than low and very low literature-defined cut points (i.e., 20 and 10 mg/L) were noted for 2 subjects (4%) and 1 subject (2%), respectively. For intermittent PZA dosing, 1 subject (4%) had a 2-h concentration that was less than the low cut point (25 mg/L). Correlations between 2-h concentration and AUC estimates based on 2- or 3-time point concentration determinations were strong. In HIV-infected persons receiving antituberculosis regimens containing PZA, lower-than-expected 2-h concentrations are uncommon. For therapeutic monitoring of PZA drug exposure, determination of a 2-h postdose concentration appears as reliable as 2- or 3-time point estimates of the AUC for PZA.

This multicenter, randomized, open-label phase 3 clinical trial compared the safety and efficacy of 3 clarithromycin-containing combination regimens for the treatment of disseminated Mycobacterium avium complex (MAC) disease in persons with acquired immunodeficiency syndrome. A total of 160 eligible patients with bacteremic MAC disease were randomized to receive clarithromycin with either ethambutol (C+E), rifabutin (C+R), or both (C+E+R) for 48 weeks. After 12 weeks of treatment, the proportion of subjects with a complete microbiologic response was not statistically significantly different among treatment arms: the proportion was 40% in the C+E group, 42% in the C+R group, and 51% in the C+E+R group (P=.454). The proportion of patients with complete or partial responses who experienced a relapse while receiving C+R (24%) was significantly higher than that of patients receiving C+E+R (6%; P=.027) and marginally higher than that of patients receiving C+E (7%; P=.057). Subjects in the C+E+R group had improved survival, compared with the C+E group (hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.23-0.83) and the C+R group (HR, 0.49; 95% CI, 0.26-0.92).

The present nonrandomized prospective study evaluated whether antimycobacterial therapy for disseminated Mycobacterium avium complex (MAC) could be withdrawn from human immunodeficiency virus-infected subjects who experienced immunologic recovery while receiving highly active antiretroviral therapy (HAART). Eligible subjects had received macrolide-based therapy for least 12 months, were asymptomatic for MAC, had received HAART for at least 16 weeks, and had CD4+ T cell counts >100 cells/microL. Forty-eight subjects were enrolled, with a median CD4+ T cell count of 240 cells/microL at the time of discontinuation of MAC therapy. Forty-seven subjects remained MAC free, whereas 1 subject developed localized MAC osteomyelitis. The median duration of follow-up while not receiving therapy was 77 weeks, and the incidence of MAC infection was 1.44/100 person-years (95% confidence interval, 0.04-8.01). Withdrawal of anti-MAC therapy appears to be safe in patients who have been treated with a macrolide-based regimen for at least 1 year and have an immunologic response on HAART.

In this international, noncomparative, randomized phase II trial, we evaluated the effectiveness and tolerance of atovaquone suspension (1500 mg orally twice daily) plus either pyrimethamine (75 mg per day after a 200-mg loading dose) or sulfadiazine (1500 mg 4 times daily) as treatment for acute disease (for 6 weeks) and as maintenance therapy (for 42 weeks) for toxoplasmic encephalitis (TE) in patients infected with human immunodeficiency virus. Twenty-one (75%) of 28 patients receiving pyrimethamine (95% lower confidence interval [CI], 58%) and 9 (82%) of 11 patients receiving sulfadiazine (95% lower CI, 53%) responded to treatment for acute disease. Of 20 patients in the maintenance phase, only 1 experienced relapse. Eleven (28%) of 40 eligible patients discontinued treatment as a result of adverse events, 9 because of nausea and vomiting or intolerance of the taste of the atovaquone suspension. Although gastrointestinal side effects were frequent, atovaquone-containing regimens are otherwise well tolerated and safe and may be useful for patients intolerant of standard regimens for toxoplasmic encephalitis.

In sequential clinical trials of treatment for histoplasmosis in patients with acquired immunodeficiency syndrome, therapy with fluconazole failed in a higher proportion of patients than did therapy with itraconazole. To determine the cause for failure with fluconazole, antifungal susceptibility testing that used modified National Committee on Clinical Laboratory Standards procedures was performed on all baseline and failure isolates. Failure occurred more frequently in patients with baseline isolates with fluconazole minimum inhibitory concentrations (MICs) > or =5 microg/mL versus lower MICs; 29% versus 3%, respectively. There was at least a 4-fold increase in fluconazole MIC in the isolates from 10 (59%) of 17 patients for whom paired pretreatment and failure or relapse isolates were available. Cross-resistance to itraconazole was not seen. In conclusion, fluconazole is less active than itraconazole for Histoplasma capsulatum and induces resistance during therapy, which accounted for treatment failure in some patients.

Animal studies have shown that fungal burden correlates with survival during treatment with new antifungal therapies for histoplasmosis. The purpose of this report is to compare the clearance of fungal burden in patients with histoplasmosis treated with liposomal amphotericin B versus itraconazole. In two separate closed clinical trials that evaluated the efficacy of liposomal amphotericin B and itraconazole treatment of disseminated histoplasmosis in patients with AIDS, blood was cultured for fungus and blood and urine were tested for Histoplasma antigen. The clinical response rates were similar; 86% with liposomal amphotericin B ( n = 51) versus 85% with itraconazole ( n = 59). Of the patients with positive blood cultures at enrollment, after 2 weeks of therapy cultures were negative in over 85% of the liposomal amphotericin B group versus 53% of the itraconazole group ( P = 0.0008). Furthermore, after 2 weeks, median antigen levels in serum fell by 1.6 U in the liposomal amphotericin B group versus 0.1 U in the itraconazole group ( P = 0.02), and those in urine fell by 2.1 U in the liposomal amphotericin B group and 0.2 U in the itraconazole group ( P = 0.0005). The more rapid clearance of fungemia supports the use of liposomal amphotericin B rather than itraconazole for initial treatment of moderately severe or severe histoplasmosis.

Background Several agents are effective in preventing Mycobacterium avium complex disease in patients with advanced human immunodeficiency virus (HIV) infection. However, there is uncertainty about whether prophylaxis should be continued in patients whose CD4+ cell counts have increased substantially with antiviral therapy. Methods We conducted a multicenter, double-blind, randomized trial of treatment with azithromycin (1200 mg weekly) as compared with placebo in HIV-infected patients whose CD4+ cell counts had increased from less than 50 to more than 100 per cubic millimeter in response to antiretroviral therapy. The primary end point was M. avium complex disease or bacterial pneumonia. Results A total of 520 patients entered the study; the median CD4+ cell count at entry was 230 per cubic millimeter. In 48 percent of the patients, the HIV RNA value was below the level of quantification. The median prior nadir CD4+ cell count was 23 per cubic millimeter, and 65 percent of the patients had had an acquire...

The efficacy and safety of clarithromycin and rifabutin alone and in combination for prevention of Mycobacterium avium complex (MAC) disease were compared in 1178 patients with AIDS who had < or =100 CD4 T cells/microL in a randomized, double-blind, placebo-controlled trial. MAC disease occurred in 9%, 15%, and 7% of those randomized to clarithromycin or rifabutin alone or in combination, respectively; time-adjusted event rates per 100 patient-years (95% confidence interval [CI]) were 6.3 (4.2-8.3), 10.5 (7.8-13.2), and 4. 7 (2.9-6.5). Risk of MAC disease was reduced by 44% with clarithromycin (risk ratio [RR], 0.56; 95% CI, 0.37-0.84; P=.005) and by 57% with combination therapy (RR, 0.43; 95% CI, 0.27-0.69; P=. 0003), versus rifabutin. Combination therapy was not more effective than clarithromycin (RR, 0.79; 95% CI, 0.48-1.31; P=.36). Of those in whom clarithromycin or combination therapy failed, 29% and 27% of MAC isolates, respectively, were resistant to clarithromycin. There were no survival differences. Clarithromycin and combination therapy were more effective than rifabutin for prevention of MAC disease, but combination therapy was associated with more adverse effects (31%; P

We enrolled 2,625 human immunodeficiency virus-infected patients into a randomized trial to assess the efficacy and tolerability of daily vs. thrice-weekly trimethoprim-sulfamethoxazole (160 mg/800 mg) for prophylaxis of Pneumocystis carinii pneumonia (PCP). The rate of PCP was 3.5 and 4.1 per 100 person-years in the daily and thrice-weekly groups, respectively, with a relative risk (RR) of 0.82 (95% confidence interval [CI], 0.61-1.09; P = .16) (RR of

The relationship between Mycobacterium avium complex (MAC) infection of blood and bone marrow was studied in human immunodeficiency virus-infected patients before and during treatment. Quantitative cultures were obtained at baseline from 17 persons with newly detected MAC bacteremia. Serial blood cultures were obtained, and a second bone marrow sample was obtained at 4 or 8 weeks. At baseline, the median MAC load in bone marrow core samples was 3 log10 higher than in blood. Bone marrow MAC loads ranged widely (866-847,315 cfu/g), and no significant correlation was found between MAC load in blood and that in bone marrow core samples. MAC loads in bilateral bone marrow biopsy samples from 7 subjects were highly correlated. MAC loads declined in blood and bone marrow at similar rates during therapy, but blood was sterilized before bone marrow. Length of survival was inversely associated with initial bone marrow core MAC load but not with blood MAC load. Initiation of treatment when tissue MAC load is low may increase the likelihood of favorable clinical outcome.

The optimal regimen for treatment of Mycobacterium avium complex (MAC) disease has not been established. Eighty-five AIDS patients with disseminated MAC disease were randomized to receive a three-drug regimen of clarithromycin, rifabutin or clofazimine, and ethambutol. Two dosages of clarithromycin, 500 or 1,000 mg twice daily (b.i.d.), were compared. The Data and Safety Monitoring Board recommended discontinuation of the clarithromycin dosage comparison and continuation of the rifabutin vs. clofazimine comparison. After a mean follow-up of 4.5 months, 10 (22%) of 45 patients receiving clarithromycin at 500 mg b.i.d. had died (70 deaths per 100 person-years) compared with 17 (43%) of 40 patients receiving clarithromycin at 1,000 mg b.i.d. (158 deaths per 100 person-years) (relative risk, 2.43; 95% confidence interval, 1.11-5.34; P = .02). After 10.4 months, 20 (49%) of 41 patients receiving rifabutin had died (81 deaths per 100 person-years) compared with 23 (52%) of 44 patients receiving clofazimine (94 deaths per 100 person-years) (relative risk, 1.20; 95% confidence interval, 0.65-2.19; P = .56). Bacteriologic outcomes were similar among treatment groups. In treating MAC disease in AIDS patients, the maximum dose of clarithromycin should be 500 mg b.i.d.

This study was designed to compare the effectiveness of fluconazole vs. itraconazole as maintenance therapy for AIDS-associated cryptococcal meningitis. HIV-infected patients who had been successfully treated (achieved negative culture of CSF) for a first episode of cryptococcal meningitis were randomized to receive fluconazole or itraconazole, both at 200 mgld, for 12 months. The study was stopped prematurely on the recommendation of an independent Data Safety and Monitoring Board. At the time, 13 (23%) of 57 itraconazole recipients had experienced culture-positive relapse, compared with 2 relapses (4%) noted among 51 fluconazole recipients (P = .006). The factor best associated with relapse was the patient having not received flucytosine during the initial 2 weeks of primary treatment for cryptococcal disease (relative risk = 5.88; 95% confidence interval, 1.27-27.14; P = .04). Fluconazole remains the treatment of choice for maintenance therapy for AIDS-associated cryptococcal disease. Flucytosine may contribute to the prevention of relapse if used during the first 2 weeks of primary therapy.

Background Although trimethoprim–sulfamethoxazole is the drug of choice for the prevention of Pneumocystis carinii pneumonia, many patients cannot tolerate it and must switch to an alternative agent. Methods We conducted a multicenter, open-label, randomized trial comparing daily atovaquone (1500-mg suspension) with daily dapsone (100 mg) for the prevention of P. carinii pneumonia among patients infected with the human immunodeficiency virus who could not tolerate trimethoprim–sulfamethoxazole. The median follow-up period was 27 months. Results Of 1057 patients enrolled, 298 had a history of P. carinii pneumonia. P. carinii pneumonia developed in 122 of 536 patients assigned to atovaquone (15.7 cases per 100 person-years), as compared with 135 of 521 in the dapsone group (18.4 cases per 100 person-years; relative risk for atovaquone vs. dapsone, 0.85; 95 percent confidence interval, 0.67 to 1.09; P=0.20). The relative risk of death was 1.07 (95 percent confidence interval, 0.89 to 1.30; P=0.45), and the r...

Objective To determine the clinical and microbiologic benefit of adding amikacin to a four-drug oral regimen for treatment of disseminated Mycobacterium avium infection in HIV-infected patients. Design A randomized, open-labeled, comparative trial. Setting Outpatient clinics. Patients Seventy-four patients with HIV and symptomatic bacteremic M. avium infection. Interventions Rifampin 10 mg/kg daily, ciprofloxacin 500 mg twice daily, clofazimine 100 mg every day, and ethambutol 15 mg/kg orally daily for 24 weeks, with or without amikacin 10 mg/kg intravenously or intramuscularly 5 days weekly for the first 4 weeks. Main outcome measure Clinical and microbiologic response at 4 weeks; quantitative level of bacteremia with M. avium. Results No difference in clinical response was noted with the addition of amikacin to the four-drug oral regimen, and only 25% in either group had a complete or partial response at 4 weeks. A comparable quantitative decrease in bacteremia was noted in both treatment groups, with 16% of patients being culture-negative at 4 weeks and 38% at 12 weeks. Toxicities were mainly gastrointestinal. Amikacin was well tolerated. Median survival was 30 weeks in both groups. Conclusions The addition of amikacin to a four-drug oral regimen of rifampin, ciprofloxacin, clofazimine, and ethambutol did not provide clinical or microbiologic benefit.

Randomized clinical trials analyzed by the intent-to-treat approach provide unbiased comparisons among treatment groups. To avoid dilution of treatment effect, many people also perform an analysis by treatment actually received, although this method may introduce bias into the results. This paper presents several approaches used for analyzing data of a recent trial and the difficulties encountered in interpreting the results of each approach. The ANRS 005/ACTG 154 Study was a double-blind, placebo-controlled, randomized, international (French, U.S., and Spanish) multicenter trial designed to assess the effectiveness of pyrimethamine for the primary prophylaxis of cerebral toxoplasmosis (CT) in HIV-infected patients with advanced immunodeficiency. In the intention-to-treat analysis, the cumulative probability of CT at 1 year did not differ significantly between the pyrimethamine arm (11.9%) and the placebo arm (13.1%), Hazard Ratio (HR) = 0.94 (95% Confidence Interval (CI) = 0.62-1.42), whereas an on-treatment analysis resulted in a significant difference: 4.2% in the pyrimethamine arm and 12.4% in the placebo arm, HR = 0.44 (95% CI = 0.24-0.80). The data showed a significant interaction between compliance and treatment outcome; and side effects were more frequently cited as reasons for compliance violations in the pyrimethamine group. Several different analytic approaches (censoring data at the time patients discontinued the study medication only for selected reasons) failed to explain the disparity between the estimation of effect of pyrimethamine by the intention-to-treat and on-treatment analyses. This experience led us to believe that comparing the results of both analyses was the best method to convince clinicians that intention-to-treat was the only interpretable analysis. We were concerned that even if pyrimethamine had a beneficial effect, it was very difficult (1) to quantify and (2) to apply to clinical practice unless one could predict the occurrence of study drug discontinuation for each patient at the time of treatment assignment. Although exploratory analyses may yield clinically relevant information and useful clarifications in the evaluation of treatments, intention-to-treat remains the only interpretable analysis of clinical trials.

This study examined whether adding levofloxacin to a standard four-drug regimen improved the 8-week culture response and compared effectiveness of 9 versus 6 months of intermittent therapy for human immunodeficiency virus-related pansusceptible pulmonary tuberculosis. Patients were randomized to receive either four or five drugs, the fifth being levofloxacin. Patients who completed induction therapy were randomized to complete 9 versus 6 months of intermittent therapy with isoniazid and rifampin. In the randomized induction phase, 97.3% of patients in the four-drug group and 95.8% in the five-drug group had sputum culture conversion at 8 weeks (P = 1.00). In the continuation phase, one patient (2%) assigned to 9 months and two patients (3.9%) assigned to 6 months of therapy had treatment failure/relapse (P = 1.00). In conclusion, this study showed that levofloxacin added no benefit to a highly effective, largely intermittent, four-drug induction regimen. Both 9 and 6 months of intermittent therapy were associated with low treatment failure/relapse rates.