Effect of Metformin on Plasma Exposure of Rifampicin, Isoniazid, and Pyrazinamide in Patients on Treatment for Pulmonary Tuberculosis

BACKGROUND

To evaluate the effect of metformin on the plasma levels of rifampicin, isoniazid, and pyrazinamide in patients with drug-sensitive pulmonary tuberculosis being treated with first-line antituberculosis treatment (ATT) and to assess the influence of gene polymorphisms on the metabolic pathway of metformin and plasma levels of antitubercular drugs.

METHODS

Nondiabetic adults aged 18-60 years with pulmonary tuberculosis were randomized to either the standard ATT (ATT group) or ATT plus metformin (METRIF group) groups in a phase IIB clinical trial. An intensive pharmacokinetic study with blood collection at 0 hour (predosing), followed by 1, 2, 4, 6, 8, and 12 hours after dosing was conducted during the first month of treatment in a subset of 60 study participants after a minimum of 14 doses. Plasma concentrations of rifampicin, isoniazid, pyrazinamide, and metformin were measured by high-performance liquid chromatography using validated methods, and pharmacokinetic parameters and OCT1 and MATE1 gene polymorphisms were compared between the groups.

RESULTS

Significant increases in the clearance of rifampicin, isoniazid, and pyrazinamide were observed in patients in the METRIF group (n = 29) compared with those in the ATT group (n = 31). The AA genotypes of the single-nucleotide polymorphism of rs2289669 ( MATE1 ) in the METRIF group showed a significantly decreased area under the concentration-time curve to the last observation point and increased clearance of rifampicin.

CONCLUSIONS

Metformin altered rifampicin and isoniazid plasma concentrations in patients receiving antituberculosis treatment for pulmonary tuberculosis with little effect on sputum conversion at the end of treatment. Studies with larger sample sizes are needed to understand host drug-drug interactions.

Efficacy and safety of the all-oral bedaquiline-containing regimen as treatment for pediatric multidrug/rifampicin-resistant tuberculosis: a multicenter, retrospective, cohort study

OBJECTIVE

The study aimed to observe the efficacy and safety of an all-oral bedaquiline (BDQ)-containing regimen for pediatric multidrug/rifampicin-resistant tuberculosis (MDR/RR-TB) through a multicenter, retrospective study in China.

METHODS

In the study, pediatric patients receiving all-oral BDQ-containing regimen (BDQ group) with clinical matched control group were included, the control group received an injection-containing regimen. The treatment outcomes and the incidence of adverse events (AEs) were compared and analyzed.

RESULTS

79 pediatric patients were enrolled, including 37 cases in BDQ group and 42 cases in the control group, the median age was 12 {8-16} and 11 {9-15} in both groups respectively. Favorable treatment outcome and cure rate in BDQ group were significantly higher than those in control group (100%vs 83.3%, p 0.03; 94.6%vs 63.3%, p 0.00). Median time of sputum culture conversion in BDQ group was significantly shorter than that in the control group (4 weeks vs 8 weeks, p 0.00). The incidence of AEs in the BDQ group was significantly less than that in the control group (48.6% vs 71.4%, p 0.03). No AEs leading to treatment discontinuation of BDQ occurred.

CONCLUSIONS

The all-oral BDQ-containing regimens may be effective and safe in the Chinese pediatric population.

Therapeutic drug monitoring and TB treatment outcomes in patients with diabetes mellitus

BACKGROUND: Diabetes mellitus (DM) increases the risk of TB disease and poor treatment outcomes such as delayed sputum culture conversion due to inadequate drug exposure. Therapeutic drug monitoring (TDM) has improved these outcomes in some settings.METHODS: To compare treatment outcomes in programs with routine TDM vs. programs that did not use TDM, we conducted a retrospective study among people with DM and TB at health departments in four US states.RESULTS: A total of 170 patients were enrolled (73 patients in the non-TDM group and 97 patients in the TDM group). Days to sputum culture conversion and total treatment duration were significantly shorter in the TDM group vs. the non-TDM group. In adjusted analyses, patients who underwent TDM were significantly more likely to achieve sputum culture conversion at 2 months (P = 0.007).CONCLUSION: TDM hastened microbiological cure from TB among people with DM and a high risk for poor treatment outcomes in the programmatic setting.

Explorative Analysis of Treatment Outcomes of Levofloxacin- and Moxifloxacin-Based Regimens and Outcome Predictors in Ethiopian MDR-TB Patients: A Prospective Observational Cohort Study

Purpose/Background

Although Ethiopia is among the thirty high multi-drug resistant tuberculosis (MDR-TB) burden countries in the world, comparative therapeutic efficacy of moxifloxacin and levofloxacin has not been explored, particularly in MDR-TB patients. We therefore aimed to prospectively compare clinical outcomes and determine potential predictors of the outcomes among patients on moxifloxacin or levofloxacin-based MDR-TB drug regimens.

Methods

We analyzed clinical parameters and laboratory data of eighty MDR-TB patients on moxifloxacin- or levofloxacin-based regimens. The clinical outcomes were compared using the Kaplan–Meier survival functions and the outcome definitions of the 2013 World Health Organization. Monthly sputum culture conversions and a molecular line probe assay results were also assessed. Observed outcomes and patient-related variables between the two groups were compared using chi-square, Wilcoxon Rank and Fisher exact tests. We also determined the potential predictors influencing treatment outcomes of moxifloxacin and levofloxacin using Cox proportional hazard model.

Results

The levofloxacin-based treatment group had a lower failure rate and adverse drug events as well as better treatment success than the moxifloxacin-based group. Overall treatment success was 65%. Disaggregating the data revealed that 53.8% were cured, 11.2% completed treatment, 10.0% died, 11.2% failed, and 13.8% were lost-to-follow-up. The line probe assay result showed that 11.3% of the clinical isolates were resistant to fluoroquinolones and 3.8% were resistant to both fluoroquinolones and injectable anti-TB agents. Treatment regimen type, culture conversion rate, alcohol use, cavity lesion, serum levels of creatinine and alanine aminotransferase were independent predictors of treatment outcome.

Conclusion

The levofloxacin-based regimen group has a better overall treatment success than the moxifloxacin-based group among MDR-TB patients. Clinical parameters and substance use history of the patients influenced treatment outcomes. We recommend further broader clinical studies to substantiate our findings as an input to review MDR-TB treatment guidelines.

9-12 months short treatment for patients with MDR-TB increases treatment success in Kyrgyzstan

INTRODUCTION

MDR/RR-TB is a growing problem in Kyrgyzstan. In 2005, the country introduced standard or individualized treatment for 20-24 months. Because of poor treatment outcomes, in 2017 a short treatment with strict eligibility criteria was introduced. The aim of this study was to compare characteristics and treatment outcomes of MDR/RR-TB patients receiving short (9-12 months) treatment in 2017 with those receiving standard or individualized (20-24 months) treatment in 2016/2017.

METHODOLOGY

A comparative cohort study using routine programmatic data. Characteristics, sputum culture conversion and treatment outcomes were compared between those on short treatment with those on standard/individualized treatment using the chi-square test, crude and adjusted risk ratios (RR and aRR).

RESULTS

The study included 274, 82 and 132 patients on standard, individualized and short treatment, respectively. There were more females, fewer migrants/homeless and unemployed and more new TB patients on short treatment compared with the other two groups. A favorable outcome (cure and treatment completed) was significantly higher in short treatment patients (83%) compared with those on standard (50%) or individualized (59%) treatment (p < 0.001). There was higher 1-month sputum culture conversion with short treatment (35%) compared with the other two groups (19% and 24%, p < 0.05). Short treatment (aRR 1.6, 1.4-1.8), female gender (aRR 1.2, 1.1-1.4), not being homeless (aRR 12.9, 4.5-17.3) and having new TB (aRR 1.3, 1.0-1.5) were independently associated with a favorable outcome.

CONCLUSIONS

The treatment success was higher in selected MDR-TB patients given short treatment in Kyrgyzstan: this regimen should be scaled-up to all MDR-TB patients.

Amikacin liposome inhalation suspension as a treatment for patients with refractory mycobacterium avium complex lung infection

Introduction: Amikacin liposome inhalation suspension (ALIS) contains amikacin sulfate, an aminoglycoside antibacterial drug. It has been approved in the US as a combined antibiotic treatment for refractory MAC lung disease patients. ALIS, as an inhaled antibiotic, can deliver amikacin to the infected site effectively and reduce systemic toxicity.Areas covered: This article gives a summated review of the pharmacodynamics, pharmacokinetics, therapeutic efficacy, post-marketing surveillance, and regulatory affairs of ALIS as an add-on therapy for MAC lung disease in adults by analyzing data from preclinical studies, clinical trials and original studies. We systematically searched Medline/PubMed through October 2020.Expert opinion: Studies demonstrate that ALIS as an add-on treatment significantly improve the rate of sputum culture conversion in MAC lung disease patients compare to guideline-recommended therapy only. The ALIS treatment showed a similar risk of serious adverse events and a low chance of renal adverse events. However, ALIS was associated with more respiratory adverse events than guideline-recommended therapy only. There was not sufficient data to conclude that ALIS treatment can improve clinical outcomes; however, with the significant improvement in the microbiology outcome in MAC lung disease patients, ALIS showed its potential use as an adjunct treatment for treating MAC lung disease.

Treatment Outcomes of Extensively Drug-Resistant Tuberculosis in Pakistan: A Countrywide Retrospective Record Review

Background: The current study is conducted with the aim to the fill the gap of information regarding treatment outcomes and variables associated with unsuccessful outcome among XDR-TB patients from Pakistan. Methods: A total of 404 culture confirmed XDR-TB patients who received treatment between 1^st May 2010 and June 30, 2017 at 27 treatment centers all over Pakistan were retrospectively followed until their treatment outcomes were reported. A p-value <0.05 reflected a statistical significant association. Results: The patients had a mean age 32.9 ± 14.1 years. The overall treatment success rate was 40.6% (95% confidence interval [CI]:35.80-45.60%). A total of 155 (38.4%) patients were declared cured, 9 (2.2%) completed treatment, 149 (36.9%) died, 60 (14.9%) failed treatment and 31 (7.7%) were lost to follow up (LTFU). The results of the multivariate binary logistic regression analysis revealed that the patients' age of >60 years (OR = 4.69, 95%CI:1.57-15.57) and receiving high dose isoniazid (OR = 2.36, 95%CI:1.14-4.85) had statistically significant positive association with death, whereas baseline body weight >40 kg (OR = 0.43, 95%CI:0.25-0.73) and sputum culture conversion in the initial two months of treatment (OR = 0.33, 95%CI:0.19-0.58) had statistically significant negative association with death. Moreover, male gender had statistically significant positive association (OR = 1.92, 95%CI:1.04-3.54) with LTFU. Conclusion: The treatment success rate (40.6%) of XDR-TB patients in Pakistan was poor. Providing special attention and enhanced clinical management to patients with identified risk factors for death and LTFU in the current cohort may improve the treatment outcomes.

Time to sputum culture conversion and its predictors among patients with multidrug-resistant tuberculosis in Hangzhou, China: A retrospective cohort study

The objective is to investigate the time to initial sputum culture conversion (SCC) and its predictors among multidrug-resistant tuberculosis (MDR-TB) patients in Hangzhou, China.A retrospective cohort study was conducted among patients who initiated MDR-TB treatment from 2011 to 2015 in Hangzhou, China. Successful achievement of initial SCC was defined as 2 consecutive negative cultures taken at least 30 days apart after initiation of treatment of MDR-TB. Successful treatment outcomes included being cured and completing treatment, while poor treatment outcomes included treatment failure, loss to follow-up, and death. Time to initial SCC was analyzed using the Kaplan-Meier method, and Cox proportional hazards regression was used to identify predictors of SCC.Among 384 patients enrolled with MDR-TB, 359 (93.5%) successfully achieved initial SCC after a median of 85 days (interquartile range, 40-112 days). A higher rate of SCC was observed in participants with successful treatment outcomes than those with poor treatment outcomes (P<.01). Multivariate analysis showed that age 25 to 64 years (compared with age<25; adjusted odds ratio [AOR], 0.7; 95% confidence interval [CI], 0.5-0.9; P < .01), age ≥65 years (compared with age < 25; AOR, 0.5; 95% CI, 0.3-0.8; P < .01), and household registration in Hangzhou (compared with non-Hangzhou registration; AOR, 1.3; 95% CI, 1.0-1.5; P < .05) were found to be associated with SCC.Although high SCC and treatment success rates were observed among MDR-TB patients in Hangzhou, the prolonged duration to initial SCC underscores the importance of emphasizing measures for infection control. A new policy of shifting outpatient treatment to inpatient treatment in China may reduce the risk of transmission from patients in the time window prior to SCC.

Liaison of Sugar Control With Time to Sputum Culture Conversion in Multi-Drug Resistant Tuberculosis

Background

Many elements have been studied repeatedly that influence time to sputum culture conversion in multi-drug resistant tuberculosis (MDR-TB). Deranged sugars not only hamper one’s infection contesting ability but also increase the chances of drug resistance. Our aim was to establish whether or not glycemic control alters MDR-TB treatment outcome.

Methods

A prospective cohort study was conducted at the TB Clinic of Jinnah Postgraduate Medical Center, Karachi, Pakistan. Newly diagnosed MDR-TB cases were started on WHO-recommended treatment regime. HbA1c (hemoglobin A1c or glycated hemoglobin) was tested at the start of treatment irrespective of the previous diabetic status. Sputum samples, 30 days apart, were taken during the initial phase of the MDR TB treatment until two consecutive samples showed conversion. Pearson's correlation coefficient was calculated to see the link between time to sputum culture conversion and HbA1c.

Results

Among 47 patients, 19 (40.4%) new cases, whereas 28 (59.8%) were previously treated for drug-sensitive TB. Our 39 patients converted during six months, of which 18 (46%) converted in one month, 14 (35.9%) in two months, 6 (15.4%) in three months, and only 1 in five months. Mean time to sputum culture conversion was 1.77 ± 0.9 months. There was a slightly negative correlation between HbA1c and sputum culture conversion time (r = -0.075, p = 0.649).

Conclusions

Sugar control does not affect sputum culture conversion in MDR-TB when an optimal treatment regime is applied.

Understanding the drug exposure-response relationship of bedaquiline to predict efficacy for novel dosing regimens in the treatment of multidrug-resistant tuberculosis

AIMS

To externally validate an earlier characterized relationship between bedaquiline exposure and decline in bacterial load in a more difficult-to-treat patient population, and to explore the performances of alternative dosing regimens through simulations.

METHODS

The bedaquiline exposure-response relationship was validated using time-to-positivity data from 233 newly diagnosed or treatment-experienced patients with drug-resistant tuberculosis from the C209 open-label study. The significance of the exposure-response relationship on the bacterial clearance was compared to a constant drug effect model. Tuberculosis resistance type and the presence and duration of antituberculosis pre-treatment were evaluated as additional covariates. Alternative dosing regimens were simulated for tuberculosis patients with different types of drug resistance.

RESULTS

High bedaquiline concentrations were confirmed to be associated with faster bacterial load decline in patients, given that the exposure-effect relationship provided a significantly better fit than the constant drug effect (relative likelihood = 0.0003). The half-life of bacterial clearance was identified to be 22% longer in patients with pre-extensively drug-resistant (pre-XDR) tuberculosis (TB) and 86% longer in patients with extensively drug-resistant (XDR) TB, compared to patients with multidrug-resistant (MDR) TB. Achievement of the same treatment response for (pre-)XDR TB patients as for MDR TB patients would be possible by adjusting the dose and dosing frequency. Furthermore, daily bedaquiline administration as in the ZeNix regimen, was predicted to be as effective as the approved regimen.

CONCLUSION

The confirmed bedaquiline exposure-response relationship offers the possibility to predict efficacy under alternative dosing regimens, and provides a useful tool for potential treatment optimization.

Increasing Number and Volume of Cavitary Lesions on Chest Computed Tomography Are Associated With Prolonged Time to Culture Conversion in Pulmonary Tuberculosis

Background

Cavitary lesions (CLs) primarily identified by chest x-ray (CXR) have been associated with worse clinical outcomes among patients with pulmonary tuberculosis (PTB). Chest computed tomography (CT), which has better resolution and increased sensitivity to detect lung abnormalities, has been understudied in PTB patients. We compared detection of CLs by CT and CXR and assessed their association with time to sputum culture conversion (tSCC).

Methods

This was a retrospective cohort study of 141 PTB patients who underwent CT. We used multivariate Cox proportional hazards models to evaluate the association between CLs on CXR and the number and single largest volume of CLs on CT with tSCC.

Results

Thirty (21%) and 75 (53%) patients had CLs on CXR and CT, respectively. CT detected cavities in an additional 44 patients (31%) compared with CXR. After multivariable adjustment, we observed a negative association between CLs and tSCC, with an adjusted hazard ratio (aHR) of 0.56 (95% confidence interval [CI], 0.32 to 0.97) for single CLs and 0.31 (95% CI, 0.16 to 0.60) for multiple CLs present on CT. Patients with a CL volume ≥25 mL had a prolonged tSCC (aHR, 0.39; 95% CI, 0.21 to 0.72). CLs on CXR were not associated with increased tSCC after multivariable adjustment.

Conclusions

CT detected a larger number of cavities in patients with PTB relative to CXR. We observed an association between increasing number and volume of CLs on CT and delayed tSCC independent of sputum microscopy result. Our findings highlight a potential role for CT in the clinical and research setting as a tool to risk-stratify patients with PTB.

Sputum bacteriology conversion and treatment outcome of patients with multidrug-resistant tuberculosis

Purpose

Multidrug-resistant tuberculosis (MDR-TB) requires long-term treatment, has a high fatality rate, and constitutes a global threat. Earlier detection of treatment failure is required to predict therapeutic efficacy.

Patients and methods

We enrolled MDR-TB patients consecutively from January 2011 through December 2012 in Lianyungang, China. Sputum smear microscopy tests and sputum cultures were performed once a month for the first 6 months following initiation of antituberculosis treatment and once every 2 months thereafter until the end of therapy. The sensitivity, specificity and area under the receiver operating characteristic curve (AUC) were used with a 95% CI to estimate the role of sputum bacteriology conversion in predicting treatment outcomes.

Results

Among the 92 MDR-TB patients enrolled in this study, 40.2% had poor treatment outcomes. The median initial sputum bacteriology conversion time was 1 month. Patients having 2-month sputum smear conversions (adjusted odds ratio [OR]: 7.19, 95% CI: 2.60–19.84) or culture conversions (adjusted OR: 2.88, 95% CI: 1.11–7.45) were more likely to experience good outcomes. The sensitivity and specificity obtained when using two-month sputum smear conversions to predict treatment outcomes were 67.6% (95% CI: 50.2–82.0) and 76.4% (95% CI: 63.0–86.8), respectively. The sensitivity and specificity obtained when using 2-month culture conversions to predict treatment outcomes were 48.6% (95% CI: 32.0–65.6) and 74.5% (95% CI: 61.0–85.3), respectively. The AUC for two-month smear conversions was 0.72 (95% CI: 0.62–0.81), significantly higher than that obtained for 2-month culture conversions (0.62, 95% CI: 0.52–0.72) (χ² = 4.18, P = 0.041).

Conclusion

The prognoses of MDR-TB patients displaying persistent sputum positivity were inferior to those for whom sputum bacteriology conversion was observed. Thus, sputum smear conversion results obtained 2 months after treatment initiation may provide a potential means for predicting MDR-TB treatment outcomes.

Sputum culture conversion as a prognostic marker for end-of-treatment outcome in patients with multidrug-resistant tuberculosis: a secondary analysis of data from two observational cohort studies

BACKGROUND

Sputum culture conversion is often used as an early microbiological endpoint in phase 2 clinical trials of tuberculosis treatment on the basis of its assumed predictive value for end-of-treatment outcome, particularly in patients with drug-susceptible tuberculosis. We aimed to assess the validity of sputum culture conversion on solid media at varying timepoints, and the time to conversion, as prognostic markers for end-of-treatment outcome in patients with multidrug-resistant (MDR) tuberculosis.

METHODS

We analysed data from two large cohort studies of patients with MDR tuberculosis. We defined sputum culture conversion as two or more consecutive negative cultures from sputum samples obtained at least 30 days apart. To estimate the association of 2 month and 6 month conversion with successful treatment outcome, we calculated odds ratios (ORs) and 95% CIs with random-effects multivariable logistic regression. We calculated predictive values with bivariate random-effects generalised linear mixed modelling.

FINDINGS

We assessed data for 1712 patients who had treatment success, treatment failure, or who died. Among patients with treatment success, median time to sputum culture conversion was significantly shorter than in those who had poor outcomes (2 months [IQR 1-3] vs 7 months [3 to ≥24]; log-rank p<0·0001). Furthermore, conversion status at 6 months (adjusted OR 14·07 [95% CI 10·05-19·71]) was significantly associated with treatment success compared with failure or death. Sputum culture conversion status at 2 months was significantly associated with treatment success only in patients who were HIV negative (adjusted OR 4·12 [95% CI 2·25-7·54]) or who had unknown HIV infection (3·59 [1·96-6·58]), but not in those who were HIV positive (0·38 [0·12-1·18]). Thus, the overall association of sputum culture conversion with a successful outcome was substantially greater at 6 months than at 2 months. 2 month conversion had low sensitivity (27·3% [95% confidence limit 16·6-41·4]) and high specificity (89·8% [82·3-94·4]) for prediction of treatment success. Conversely, 6 month sputum culture conversion status had high sensitivity (91·8% [85·9-95·4]), but moderate specificity (57·8% [42·5-71·6]). The maximum combined sensitivity and specificity for sputum culture conversion was reached between month 6 and month 10 of treatment.

INTERPRETATION

Time to sputum culture conversion, conversion status at 6 months, and conversion status at 2 months in patients without known HIV infection can be considered as proxy markers of end-of-treatment outcome in patients with MDR tuberculosis, although the overall association with treatment success is substantially stronger for 6 month than for 2 month conversion status. Investigators should consider these results regarding the validity of sputum culture conversion at various timepoints as an early predictor of treatment efficacy when designing phase 2 studies before investing substantial resources in large, long-term, phase 3 trials of new treatments for MDR tuberculosis.

FUNDING

US Agency for International Development, US Centers for Disease Control and Prevention, Division of Intramural Research of the US National Institute of Allergy and Infectious Diseases, Korea Centers for Disease Control and Prevention.

Corticosteroid effects on sputum culture in pulmonary tuberculosis: a meta-regression analysis

OBJECTIVES

There is increasing interest in the potential role of adjunctive anti-inflammatory therapy to accelerate tuberculosis (TB) treatment. Sputum culture conversion is an important biomarker predictor of durable TB cure.

METHODS

This study used meta-regression analysis to examine the relationship between corticosteroid dose and sputum culture conversion, using published data from controlled clinical trials including 1806 corticosteroid-treated TB patients.

RESULTS

Linear models with 2 or 3 variables, including corticosteroid dose and the proportion of culture positive control subjects, predicted therapeutic benefit of corticosteroids at 1 and 2 months. The 3-variable model predicted that 134 mg of prednisolone per day, given together with standard 4-drug TB chemotherapy, would reduce the proportion of positive culture at 2 months from 15% to 2%. The estimate accounts for a 50% reduction in steroid exposure due to rifampin. A proportion of 2% of subjects with positive cultures at 2 months has been proposed as a target for new 4-month TB regimens.

CONCLUSIONS

These positive findings must be tempered by recognition that the metabolic and cardiovascular risks of corticosteroids administered at this dose for this duration are unlikely to be acceptable when examined from a patient-level benefit-risk perspective. In future research studies to shorten TB treatment, biologic anti-inflammatory therapies with similar therapeutic effects but superior safety profiles should be considered.