A first-in-class leucyl-tRNA synthetase inhibitor, ganfeborole, for rifampicin-susceptible tuberculosis: a phase 2a open-label, randomized trial.

New tuberculosis treatments are needed to address drug resistance, lengthy treatment duration and adverse reactions of available agents. GSK3036656 (ganfeborole) is a first-in-class benzoxaborole inhibiting the Mycobacterium tuberculosis leucyl-tRNA synthetase. Here, in this phase 2a, single-center, open-label, randomized trial, we assessed early bactericidal activity (primary objective) and safety and pharmacokinetics (secondary objectives) of ganfeborole in participants with untreated, rifampicin-susceptible pulmonary tuberculosis. Overall, 75 males were treated with ganfeborole (1/5/15/30 mg) or standard of care (Rifafour e-275 or generic alternative) once daily for 14 days. We observed numerical reductions in daily sputum-derived colony-forming units from baseline in participants receiving 5, 15 and 30 mg once daily but not those receiving 1 mg ganfeborole. Adverse event rates were comparable across groups; all events were grade 1 or 2. In a participant subset, post hoc exploratory computational analysis of 18F-fluorodeoxyglucose positron emission tomography/computed tomography findings showed measurable treatment responses across several lesion types in those receiving ganfeborole 30 mg at day 14. Analysis of whole-blood transcriptional treatment response to ganfeborole 30 mg at day 14 revealed a strong association with neutrophil-dominated transcriptional modules. The demonstrated bactericidal activity and acceptable safety profile suggest that ganfeborole is a potential candidate for combination treatment of pulmonary tuberculosis.ClinicalTrials.gov identifier: NCT03557281 .

Radiological and functional evidence of the bronchial spread of tuberculosis: an observational analysis.

BACKGROUND: Direct bronchial spread of tuberculosis was extensively described in pre-antibiotic human pathology literature but this description has been overlooked in the post-antibiotic era, in which most pathology data come from animal models that emphasise the granuloma. Modern techniques, such as [18F]2-fluoro-2-deoxy-D-glucose (FDG) PET-CT scans, might provide further insight. Our aim was to understand normal early tuberculosis resolution patterns on pulmonary PET-CT scans in treated patients with tuberculosis who were subsequently cured. METHODS: In this observational analysis, we analysed data from PredictTB, an ongoing, prospective, randomised clinical trial that examined sequential baseline and week 4 FDG-PET-CT scans from participants successfully treated (sputum culture negative 18 months after enrolment) for drug-susceptible pulmonary tuberculosis in South Africa and China. Participants who were aged 18-75 years, GeneXpert MTB/RIF positive for tuberculosis and negative for rifampicin resistance, had not yet started tuberculosis treatment, had not been treated for active tuberculosis within the previous 3 years, and met basic safety laboratory criteria were included and participants with diabetes, HIV infection, or with extrapulmonary tuberculosis including pleural tuberculosis were excluded. Scans were assessed by two readers for the location of tuberculosis lesions (eg, cavities and consolidations), bronchial thickening patterns, and changes from baseline to week 4 of treatment. FINDINGS: Among the first 124 participants (enrolled from June 22, 2017, to Sept 27, 2018) who were successfully treated, 161 primarily apical cavitary lesions were identified at baseline. Bronchial thickening and inflammation linking non-cavitary consolidative lesions to cavities were observed in 121 (98%) of 124 participants' baseline PET-CT scans. After 4 weeks of treatment, 21 (17%) of 124 participants had new or expanding lesions linked to cavities via bronchial inflammation that were not present at baseline, particularly participants with two or more cavities at baseline and participants from South Africa. INTERPRETATION: In participants with pulmonary tuberculosis who were subsequently cured, the location of cavitary and non-cavitary lesions at baseline and new lesions at week 4 of treatment suggest a cavitary origin of disease and bronchial spread through the lungs. Bronchial spread from cavities might play a larger role in the spread of pulmonary tuberculosis than has been appreciated. Elucidating cavity lesion dynamics and Mycobacterium tuberculosis viability within cavities might better explain treatment outcomes and why some patients are cured and others relapse. FUNDING: Bill & Melinda Gates Foundation, European and Developing Countries Clinical Trials Partnership, China Ministry of Science and Technology, National Natural Science Foundation of China, and National Institutes of Health. TRANSLATIONS: For the Chinese, Afrikaans and Xhosa translations of the abstract see Supplementary Materials section.

Fourteen-day PET/CT imaging to monitor drug combination activity in treated individuals with tuberculosis.

Early bactericidal activity studies monitor daily sputum bacterial counts in individuals with tuberculosis (TB) for 14 days during experimental drug treatment. The rate of change in sputum bacterial load over time provides an informative, but imperfect, estimate of drug activity and is considered a critical step in development of new TB drugs. In this clinical study, 160 participants with TB received isoniazid, pyrazinamide, or rifampicin, components of first-line chemotherapy, and moxifloxacin individually and in combination. In addition to standard bacterial enumeration in sputum, participants underwent 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography and computerized tomography ([18F]FDG-PET/CT) at the beginning and end of the 14-day drug treatment. Quantitating radiological responses to drug treatment provided comparative single and combination drug activity measures across lung lesion types that correlated more closely with established clinical outcomes when combined with sputum enumeration compared to sputum enumeration alone. Rifampicin and rifampicin-containing drug combinations were most effective in reducing both lung lesion volume measured by CT imaging and lesion-associated inflammation measured by PET imaging. Moxifloxacin was not superior to rifampicin in any measure by PET/CT imaging, consistent with its performance in recent phase 3 clinical trials. PET/CT imaging revealed synergy between isoniazid and pyrazinamide and demonstrated that the activity of pyrazinamide was limited to lung lesion, showing the highest FDG uptake during the first 2 weeks of drug treatment. [18F]FDG-PET/CT imaging may be useful for measuring the activity of single drugs and drug combinations during evaluation of potential new TB drug regimens before phase 3 trials.

Current and future treatments for tuberculosis.

Guidelines on the treatment of tuberculosis (TB) have essentially remained the same for the past 35 years, but are now starting to change. Ongoing clinical trials will hopefully transform the landscape for treatment of drug sensitive TB, drug resistant TB, and latent TB infection. Multiple trials are evaluating novel agents, repurposed agents, adjunctive host directed therapies, and novel treatment strategies that will increase the probability of success of future clinical trials. Guidelines for HIV-TB co-infection treatment continue to be updated and drug resistance testing has been revolutionized in recent years with the shift from phenotypic to genotypic testing and the concomitant increased speed of results. These coming changes are long overdue and are sorely needed to address the vast disparities in global TB incidence rates. TB is currently the leading cause of death globally from a single infectious agent, but the work of many researchers and the contributions of many patients in clinical trials will reduce the substantial global morbidity and mortality of the disease.

Quantitative 18F-FDG PET-CT scan characteristics correlate with tuberculosis treatment response.

BACKGROUND: There is a growing interest in the use of F-18 FDG PET-CT to monitor tuberculosis (TB) treatment response. Tuberculosis lung lesions are often complex and diffuse, with dynamic changes during treatment and persisting metabolic activity after apparent clinical cure. This poses a challenge in quantifying scan-based markers of burden of disease and disease activity. We used semi-automated, whole lung quantification of lung lesions to analyse serial FDG PET-CT scans from the Catalysis TB Treatment Response Cohort to identify characteristics that best correlated with clinical and microbiological outcomes. RESULTS: Quantified scan metrics were already associated with clinical outcomes at diagnosis and 1 month after treatment, with further improved accuracy to differentiate clinical outcomes after standard treatment duration (month 6). A high cavity volume showed the strongest association with a risk of treatment failure (AUC 0.81 to predict failure at diagnosis), while a suboptimal reduction of the total glycolytic activity in lung lesions during treatment had the strongest association with recurrent disease (AUC 0.8 to predict pooled unfavourable outcomes). During the first year after TB treatment lesion burden reduced; but for many patients, there were continued dynamic changes of individual lesions. CONCLUSIONS: Quantification of FDG PET-CT images better characterised TB treatment outcomes than qualitative scan patterns and robustly measured the burden of disease. In future, validated metrics may be used to stratify patients and help evaluate the effectiveness of TB treatment modalities.

Neurotuberculosis: Control of Steroid-Refractory Paradoxical Inflammatory Reaction With Ruxolitinib.

Paradoxical inflammatory reactions associated with treatment of neurotuberculosis can lead to severe morbidity and mortality and may not be controlled by steroids alone. We report the use of the Janus kinase inhibitor ruxolitinib to treat a steroid-refractory neurotuberculosis paradoxical reaction.

A semi-automatic technique to quantify complex tuberculous lung lesions on 18F-fluorodeoxyglucose positron emission tomography/computerised tomography images.

BACKGROUND: There is a growing interest in the use of 18F-FDG PET-CT to monitor tuberculosis (TB) treatment response. However, TB causes complex and widespread pathology, which is challenging to segment and quantify in a reproducible manner. To address this, we developed a technique to standardise uptake (Z-score), segment and quantify tuberculous lung lesions on PET and CT concurrently, in order to track changes over time. We used open source tools and created a MATLAB script. The technique was optimised on a training set of five pulmonary tuberculosis (PTB) cases after standard TB therapy and 15 control patients with lesion-free lungs. RESULTS: We compared the proposed method to a fixed threshold (SUV > 1) and manual segmentation by two readers and piloted the technique successfully on scans of five control patients and five PTB cases (four cured and one failed treatment case), at diagnosis and after 1 and 6 months of treatment. There was a better correlation between the Z-score-based segmentation and manual segmentation than SUV > 1 and manual segmentation in terms of overall spatial overlap (measured in Dice similarity coefficient) and specificity (1 minus false positive volume fraction). However, SUV > 1 segmentation appeared more sensitive. Both the Z-score and SUV > 1 showed very low variability when measuring change over time. In addition, total glycolytic activity, calculated using segmentation by Z-score and lesion-to-background ratio, correlated well with traditional total glycolytic activity calculations. The technique quantified various PET and CT parameters, including the total glycolytic activity index, metabolic lesion volume, lesion volumes at different CT densities and combined PET and CT parameters. The quantified metrics showed a marked decrease in the cured cases, with changes already apparent at month one, but remained largely unchanged in the failed treatment case. CONCLUSIONS: Our technique is promising to segment and quantify the lung scans of pulmonary tuberculosis patients in a semi-automatic manner, appropriate for measuring treatment response. Further validation is required in larger cohorts.

Corrigendum: Persisting positron emission tomography lesion activity and Mycobacterium tuberculosis mRNA after tuberculosis cure.

This corrects the article DOI: 10.1038/nm.4177.

Evaluation of a Rapid Molecular Drug-Susceptibility Test for Tuberculosis.

BACKGROUND: Fluoroquinolones and second-line injectable drugs are the backbone of treatment regimens for multidrug-resistant tuberculosis, and resistance to these drugs defines extensively drug-resistant tuberculosis. We assessed the accuracy of an automated, cartridge-based molecular assay for the detection, directly from sputum specimens, of Mycobacterium tuberculosis with resistance to fluoroquinolones, aminoglycosides, and isoniazid. METHODS: We conducted a prospective diagnostic accuracy study to compare the investigational assay against phenotypic drug-susceptibility testing and DNA sequencing among adults in China and South Korea who had symptoms of tuberculosis. The Xpert MTB/RIF assay and sputum culture were performed. M. tuberculosis isolates underwent phenotypic drug-susceptibility testing and DNA sequencing of the genes katG, gyrA, gyrB, and rrs and of the eis and inhA promoter regions. RESULTS: Among the 308 participants who were culture-positive for M. tuberculosis, when phenotypic drug-susceptibility testing was used as the reference standard, the sensitivities of the investigational assay for detecting resistance were 83.3% for isoniazid (95% confidence interval [CI], 77.1 to 88.5), 88.4% for ofloxacin (95% CI, 80.2 to 94.1), 87.6% for moxifloxacin at a critical concentration of 0.5 µg per milliliter (95% CI, 79.0 to 93.7), 96.2% for moxifloxacin at a critical concentration of 2.0 µg per milliliter (95% CI, 87.0 to 99.5), 71.4% for kanamycin (95% CI, 56.7 to 83.4), and 70.7% for amikacin (95% CI, 54.5 to 83.9). The specificity of the assay for the detection of phenotypic resistance was 94.3% or greater for all drugs except moxifloxacin at a critical concentration of 2.0 µg per milliliter (specificity, 84.0% [95% CI, 78.9 to 88.3]). When DNA sequencing was used as the reference standard, the sensitivities of the investigational assay for detecting mutations associated with resistance were 98.1% for isoniazid (95% CI, 94.4 to 99.6), 95.8% for fluoroquinolones (95% CI, 89.6 to 98.8), 92.7% for kanamycin (95% CI, 80.1 to 98.5), and 96.8% for amikacin (95% CI, 83.3 to 99.9), and the specificity for all drugs was 99.6% (95% CI, 97.9 to 100) or greater. CONCLUSIONS: This investigational assay accurately detected M. tuberculosis mutations associated with resistance to isoniazid, fluoroquinolones, and aminoglycosides and holds promise as a rapid point-of-care test to guide therapeutic decisions for patients with tuberculosis. (Funded by the National Institute of Allergy and Infectious Diseases, National Institutes of Health, and the Ministry of Science and Technology of China; ClinicalTrials.gov number, NCT02251327 .).

Using biomarkers to predict TB treatment duration (Predict TB): a prospective, randomized, noninferiority, treatment shortening clinical trial.

Background: By the early 1980s, tuberculosis treatment was shortened from 24 to 6 months, maintaining relapse rates of 1-2%. Subsequent trials attempting shorter durations have failed, with 4-month arms consistently having relapse rates of 15-20%. One trial shortened treatment only among those without baseline cavity on chest x-ray and whose month 2 sputum culture converted to negative. The 4-month arm relapse rate decreased to 7% but was still significantly worse than the 6-month arm (1.6%, P<0.01).  We hypothesize that PET/CT characteristics at baseline, PET/CT changes at one month, and markers of residual bacterial load will identify patients with tuberculosis who can be cured with 4 months (16 weeks) of standard treatment. Methods: This is a prospective, multicenter, randomized, phase 2b, noninferiority clinical trial of pulmonary tuberculosis participants. Those eligible start standard of care treatment. PET/CT scans are done at weeks 0, 4, and 16 or 24. Participants who do not meet early treatment completion criteria (baseline radiologic severity, radiologic response at one month, and GeneXpert-detectable bacilli at four months) are placed in Arm A (24 weeks of standard therapy). Those who meet the early treatment completion criteria are randomized at week 16 to continue treatment to week 24 (Arm B) or complete treatment at week 16 (Arm C). The primary endpoint compares the treatment success rate at 18 months between Arms B and C. Discussion: Multiple biomarkers have been assessed to predict TB treatment outcomes. This study uses PET/CT scans and GeneXpert (Xpert) cycle threshold to risk stratify participants. PET/CT scans are not applicable to global public health but could be used in clinical trials to stratify participants and possibly become a surrogate endpoint. If the Predict TB trial is successful, other immunological biomarkers or transcriptional signatures that correlate with treatment outcome may be identified. TRIAL REGISTRATION: NCT02821832.

Persisting positron emission tomography lesion activity and Mycobacterium tuberculosis mRNA after tuberculosis cure.

The absence of a gold standard to determine when antibiotics induce a sterilizing cure has confounded the development of new approaches to treat pulmonary tuberculosis (PTB). We detected positron emission tomography and computerized tomography (PET-CT) imaging response patterns consistent with active disease, along with the presence of Mycobacterium tuberculosis (MTB) mRNA in sputum and bronchoalveolar lavage samples, in a substantial proportion of adult, HIV-negative patients with PTB after a standard 6-month treatment plus 1 year follow-up, including patients with a durable cure and others who later developed recurrent disease. The presence of MTB mRNA in the context of nonresolving and intensifying lesions on PET-CT images might indicate ongoing transcription, suggesting that even apparently curative treatment for PTB may not eradicate all of the MTB bacteria in most patients. This suggests an important complementary role for the immune response in maintaining a disease-free state. Sterilizing drugs or host-directed therapies, and better treatment response markers, are probably needed for the successful development of improved and shortened PTB-treatment strategies.

Severe Paradoxical Reaction During Treatment of Disseminated Tuberculosis in a Patient With Neutralizing Anti-IFNγ Autoantibodies.

Interferon-gamma (IFNγ) neutralizing autoantibodies are associated with disseminated nontuberculous mycobacterial infections. We report a previously healthy Thai woman with disseminated tuberculosis and high-titer IFNγ-neutralizing autoantibodies, who developed a severe inflammatory reaction during anti-tuberculosis treatment. IFNγ contributes to host control of tuberculosis but appears inessential for tuberculosis paradoxical reactions.

A sterilizing tuberculosis treatment regimen is associated with faster clearance of bacteria in cavitary lesions in marmosets.

Shortening the lengthy treatment duration for tuberculosis patients is a major goal of current drug development efforts. The common marmoset develops human-like disease pathology and offers an attractive model to better understand the basis for relapse and test regimens for effective shorter duration therapy. We treated Mycobacterium tuberculosis-infected marmosets with two drug regimens known to differ in their relapse rates in human clinical trials: the standard four-drug combination of isoniazid, rifampin, pyrazinamide, and ethambutol (HRZE) that has very low relapse rates and the combination of isoniazid and streptomycin that is associated with higher relapse rates. As early as 2 weeks, the more sterilizing regimen significantly reduced the volume of lung disease by computed tomography (P = 0.035) and also significantly reduced uptake of [(18)F]-2-fluoro-2-deoxyglucose by positron emission tomography (P = 0.049). After 6 weeks of therapy, both treatments caused similar reductions in granuloma bacterial load, but the more sterilizing, four-drug regimen caused greater reduction in bacterial load in cavitary lesions (P = 0.009). These findings, combined with the association in humans between cavitary disease and relapse, suggest that the basis for improved sterilizing activity of the four-drug combination is both its faster disease volume resolution and its stronger sterilizing effect on cavitary lesions. Definitive data from relapse experiments are needed to support this observation.

Expanding substance use treatment options for HIV prevention with buprenorphine-naloxone: HIV Prevention Trials Network 058.

BACKGROUND: Injection opioid use plays a significant role in the transmission of HIV infection in many communities and several regions of the world. Access to evidence-based treatments for opioid use disorders is extremely limited. METHODS: HIV Prevention Trials Network 058 (HPTN 058) was a randomized controlled trial designed to compare the impact of 2 medication-assisted treatment (MAT) strategies on HIV incidence or death among opioid-dependent people who inject drugs (PWID). HIV-negative opioid-dependent PWID were recruited from 4 communities in Thailand and China with historically high prevalence of HIV among PWID. A total of 1251 participants were randomly assigned to either (1) a 1-year intervention consisting of 2 opportunities for a 15-day detoxification with buprenorphine/naloxone (BUP/NX) combined with up to 21 sessions of behavioral drug and risk counseling [short-term medication-assisted treatment (ST-MAT)] or (2) thrice-weekly dosing for 48 weeks with BUP/NX and up to 21 counseling sessions [long-term medication-assisted treatment (LT-MAT)] followed by dose tapering. All participants were followed for 52 weeks after treatment completion to assess durability of impact. RESULTS: Although the study was stopped early due to lower than expected occurrence of the primary end points, sufficient data were available to assess the impact of the interventions on drug use and injection-related risk behavior. At week 26, 22% of ST-MAT participants had negative urinalyses for opioids compared with 57% in the LT-MAT (P < 0.001). Differences disappeared in the year after treatment: at week 78, 35% in ST-MAT and 32% in the LT-MAT had negative urinalyses. Injection-related risk behaviors were significantly reduced in both groups after randomization. CONCLUSIONS: Participants receiving BUP/NX 3 times weekly were more likely to reduce opioid injection while on active treatment. Both treatment strategies were considered safe and associated with reductions in injection-related risk behavior. These data support the use of thrice-weekly BUP/NX as a way to reduce exposure to HIV risk. Continued access to BUP/NX may be required to sustain reductions in opioid use.

Linezolid Trough Concentrations Correlate with Mitochondrial Toxicity-Related Adverse Events in the Treatment of Chronic Extensively Drug-Resistant Tuberculosis.

Long-term linezolid use is limited by mitochondrial toxicity-associated adverse events (AEs). Within a prospective, randomized controlled trial of linezolid to treat chronic extensively drug-resistant tuberculosis, we serially monitored the translational competence of mitochondria isolated from peripheral blood of participants by determining the cytochrome c oxidase/citrate synthase activity ratio. We compared this ratio with AEs associated with mitochondrial dysfunction. Linezolid trough concentrations were determined for 38 participants at both 600 mg and 300 mg doses. Those on 600 mg had a significantly higher risk of AE than those on 300 mg (HR 3·10, 95% CI 1·23-7 · 86). Mean mitochondrial function levels were significantly higher in patients before starting linezolid compared to their concentrations on 300 mg (P = 0·004) or 600 mg (P < 0·0001). Increasing mean linezolid trough concentrations were associated with lower mitochondrial function levels (Spearman's ρ = - 0.48; P = 0.005). Mitochondrial toxicity risk increased with increasing linezolid trough concentrations, with all patients with mean linezolid trough > 2 µg/ml developing an AE related to mitochondrial toxicity, whether on 300 mg or 600 mg. Therapeutic drug monitoring may be useful to prevent the development of mitochondrial toxicity associated with long-term linezolid use.

PET/CT imaging reveals a therapeutic response to oxazolidinones in macaques and humans with tuberculosis.

Oxazolidinone antibiotics such as linezolid have shown significant therapeutic effects in patients with extensively drug-resistant (XDR) tuberculosis (TB) despite modest effects in rodents and no demonstrable early bactericidal activity in human phase 2 trials. We show that monotherapy with either linezolid or AZD5847, a second-generation oxazolidinone, reduced bacterial load at necropsy in Mycobacterium tuberculosis-infected cynomolgus macaques with active TB. This effect coincided with a decline in 2-deoxy-2-[(18)F]-fluoro-d-glucose positron emission tomography (FDG PET) imaging avidity in the lungs of these animals and with reductions in pulmonary pathology measured by serial computed tomography (CT) scans over 2 months of monotherapy. In a parallel phase 2 clinical study of linezolid in patients infected with XDR-TB, we also collected PET/CT imaging data from subjects receiving linezolid that had been added to their failing treatment regimens. Quantitative comparisons of PET/CT imaging changes in these human subjects were similar in magnitude to those observed in macaques, demonstrating that the therapeutic effect of these oxazolidinones can be reproduced in this model of experimental chemotherapy. PET/CT imaging may be useful as an early quantitative measure of drug efficacy against TB in human patients.