Lan Yao

Efficacy, safety and tolerability of linezolid for the treatment of XDR-TB: a study in China

Heterogeneity amongst cohorts of patients treated for drug-resistant tuberculosis (TB) make assessing the efficacy of new drugs and regimens unreliable without randomisation [1]. We warmly welcome the randomised controlled trial (RCT) “Efficacy, safety and tolerability of linezolid for the treatment of XDR-TB: a study in China” presented by Tang et al. [2]. Linezolid is now included on the WHO list of essential medicines [3] and falling prices will improve access. That Tang et al. [2] report a 35.3% absolute reduction in the risk of a poor outcome by adding linezolid to an optimised background regimen argues in favour of wider use. Linezolid remains a WHO “Group 5” drug, classifying it as an “anti-TB drug with limited data on efficacy and/or long term safety in the treatment of [drug-resistant]-TB” [4]. The limited data on the efficacy of drugs in this class has recently been reviewed [5]. These WHO classifications may shortly be revised and the exciting results from this study have the potential to alter guidance regarding the treatment of extensively drug-resistant (XDR) TB. We note the proposal to re-classify linezolid into Group 3 in an editorial in the October edition of the European Respiratory Journal [6]. It is with this in mind that we seek some clarifications. Response to the interesting RCT on linezolid for XDR-TB and request for information which may impact new guidelines http://ow.ly/Z1dX5Linezolid may be effective in treating multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis. We conducted a prospective, multicentre, randomised study to further evaluate the efficacy, safety and tolerability of linezolid in patients with extensively drug-resistant tuberculosis in China. 65 patients who had culture-positive sputum for extensively drug-resistant tuberculosis were randomly assigned to a linezolid therapy group or a control group. Patients in the two groups adopted a 2-year individually based chemotherapy regimen. The linezolid therapy group was given linezolid at a start dose of 1200 mg per day for a period of 4-6 weeks and this was then followed by a dose of 300-600 mg per day. The proportion of sputum culture conversions in the linezolid therapy group was 78.8% by 24 months, significantly higher than that in the control group (37.6%, p<0.001). The treatment success rate in linezolid therapy group was 69.7%, significantly higher than that in the control group (34.4%, p=0.004). 27 (81.8%) patients had clinically significant adverse events in the linezolid group, of whom 25 (93%) patients had events that were possibly or probably related to linezolid. Most adverse events resolved after reducing the dosage of linezolid or temporarily discontinuing linezolid. Linezolid containing chemotherapy for treatment of extensively drug-resistant tuberculosis may significantly promote cavity closure, increase sputum culture-conversion rate and improve treatment success rate.

Clofazimine for the Treatment of Multidrug-Resistant Tuberculosis: Prospective, Multicenter, Randomized Controlled Study in China

BACKGROUND Clofazimine (Cfz) has shown activity against Mycobacterium tuberculosis, including multidrug-resistant (MDR) strains in vitro and in animal studies. Here we evaluate the clinical efficacy and tolerability of using Cfz to treat MDR tuberculosis in China. METHODS We enrolled 105 patients who had sputum culture-positive MDR tuberculosis in 6 major tuberculosis specialty hospitals in China. Patients were randomly assigned to either the Cfz therapy group (n = 53) or control group (n = 52). Patients in the 2 groups were given 21 months of individual-based chemotherapy regimens based on medication history and drug susceptibility test results. The Cfz therapy group regimens incorporated 100 mg of Cfz once daily for 21 months. RESULTS Three patients in each group discontinued therapy because of side effects or other reasons. Sputum culture conversion to negative was earlier in patients who received Cfz compared with controls (P = .042 by log-rank test). Chest computed tomography showed cavitary changes in 46 patients in the Cfz therapy group and 45 in the control group. Cavity closure was earlier in patient who received Cfz compared with controls (P = .047 by log-rank test). The treatment success rate in the Cfz group was 73.6%, higher than that in control group (53.8%; P = .035). Side effects in skin only occurred in the Cfz group. The rates of skin discoloration and ichthyosis were 94.3% and 47.2%, respectively. CONCLUSIONS Using Cfz to treat MDR tuberculosis promotes cavity closure, accelerates sputum culture conversion, and improves treatment success rates.

Risk Factors for Poor Treatment Outcomes in Patients with MDR-TB and XDR-TB in China: Retrospective Multi-Center Investigation

Background The treatment of patients with MDR- and XDR-TB is usually more complex, toxic and costly and less effective than treatment of other forms of TB. However, there is little information available on risk factors for poor outcomes in patients with MDR- and XDR-TB in China. Methodology/Principal Findings We retrospectively analyzed the clinical records of HIV-negative TB Patients with culture-proven MDR- or XDR-TB who were registered from July 2006 to June 2011 at five large-scale Tuberculosis Specialized Hospitals in China. Among 1662 HIV-seronegative TB cases which were culture-positive for M. tuberculosis complex and had positive sputum-smear microscopy results, 965 cases (58.1%) were DR-TB, and 586 cases (35.3%) were classified as having MDR-TB, accounting for 60.7% of DR-TB. 169 cases (10.2%) were XDR-TB, accounting for 17.5% of DR-TB, 28.8% of MDR-TB. The MDR-TB patients were divided into XDR-TB group (n=169) and other MDR-TB group (non-XDR MDR-TB) (n=417). In total, 240 patients (40.95%) had treatment success, and 346 (59.05%) had poor treatment outcomes. The treatment success rate in other MDR-TB group was 52.2%, significantly higher than that in the XDR-TB group (13%, P<0.001). In multivariate logistic regression analysis, poor outcomes were associated with duration of previous anti-TB treatment of more than one year (OR, 0.077; 95% CI, 0.011-0.499, P<0.001), a BMI less than 18.5 kg/m2 (OR, 2.185; 95% CI, 1.372-3.478, P<0.001), XDR (OR, 13.368; 95% CI, 6.745-26.497, P<0.001), retreatment (OR, 0.171; 95% CI, 0.093-0.314, P<0.001), diabetes (OR, 0.305; 95% CI, 0.140-0.663, P=0.003), tumor (OR, 0.095; 95% CI, 0.011-0.795, P=0.03), decreased albumin (OR, 0.181; 95% CI, 0.118-0.295, P<0.001), cavitation (OR, 0.175; 95% CI, 0.108-0.286, P<0.001). Conclusions/Significance The patients with MDR-TB and XDR-TB have poor treatment outcomes in China.The presence of extensive drug resistance, low BMI, hypoalbuminemia, comorbidity, cavitary disease and previous anti-TB treatment are independent prognostic factors for poor outcome in patients with MDR-TB.

Increased Cytokines Response in Patients with Tuberculosis Complicated with Chronic Obstructive Pulmonary Disease

Objectives To explore the change and its significance of cytokines in patients with pulmonary tuberculosis complicated with COPD. Methods The immune function of 152 cases of pulmonary tuberculosis with COPD was detected to compare with 150 cases of patients with pulmonary tuberculosis, 157 cases of patients with COPD and 50 cases of healthy volunteers who were in the hospital during the same period. T lymphocyte cell population in peripheral blood was detected by flow cytometry. The serum levels of sIL-2R, IL-6, IFN-γ, TNF-α were measured using ELISA. Results The percentage of CD4+ T cells in TB patients with or without COPD and COPD patients without TB was significantly lower than that in control group. The percentage of CD4+ T cells in patients with TB and COPD was significantly lower than that in the non-COPD TB patients. The percentage of CD8+ T cells was higher in the TB patients group than that in control group. The CD4+/CD8+ ratio in the TB patients group was significantly lower than that in control group. The concentrations of sIL-2R, IL-6, TNF-α, IFN-γ in TB patients with or without COPD and COPD patients without TB were significantly higher than those in control group. In addition, sIL-2R, IL-6, TNF-α concentrations in the patients with TB and COPD were higher than those in the non-COPD TB patients. The concentrations of sIL-2R, IL-6, TNF-α, IFN-γ in COPD patients with TB were significantly higher than those in COPD patients without TB. There was a significant negative correlation between serum levels of TNF-α, IL-6 and FEV1 (%, predicted) in COPD without TB group. Conclusions The patients with pulmonary tuberculosis complicated with COPD were impaired in cellular immunity, and its extent of immune impairment is more serious than those of the patients with pulmonary tuberculosis and the patients with COPD.

Evaluation of risk factors for false-negative results with an antigen-specific peripheral blood-based quantitative T cell assay (T-SPOT®.TB) in the diagnosis of active tuberculosis: A large-scale retrospective study in China

Objective To investigate the diagnostic efficacy of an interferon-γ release assay, T-SPOT®.TB, for diagnosing active tuberculosis (TB) and to identify risk factors for false-negative results. Methods This retrospective study enrolled consecutive patients with active TB and with non-TB respiratory diseases to evaluate the risk factors for false-negative results when using the T-SPOT®.TB assay for the diagnosis of active TB. Patients with active TB were categorized as having confirmed pulmonary TB, clinically diagnosed pulmonary TB or extrapulmonary TB (EPTB). Results This study analysed 4964 consecutive patients; 2425 with active TB and 2539 with non-TB respiratory diseases. Multivariate logistic regression analyses identified the following five factors that were all associated with an increased false-negative rate with the T-SPOT®.TB assay: increased age (odds ratio [OR] 1.018; 95% confidence interval [CI] 1.013, 1.024); decreased CD8+ count (OR 0.307; 95% CI 0.117, 0.803); negative sputum acid-fast bacilli (AFB) smear staining (OR 1.821; 95% CI 1.338, 2.477); negative mycobacterial cultures (OR 1.379; 95% CI 1.043, 1.824); and absence of EPTB (OR 1.291; 95% CI 1.026, 1.623). Conclusions Increased age, decreased CD8+ count, negative sputum AFB smear results, negative sputum mycobacterial cultures and absence of EPTB might lead to an increased false-negative rate when using the T-SPOT®.TB assay.

Parallel Tests Using Culture, Xpert MTB/RIF, and SAT-TB in Sputum Plus Bronchial Alveolar Lavage Fluid Significantly Increase Diagnostic Performance of Smear-Negative Pulmonary Tuberculosis

At present, tuberculosis remains a serious threat to human health. The diagnosis of pulmonary tuberculosis (PTB) is still difficult, and the prominent challenge for diagnosis is the lack of a highly sensitive and specific method. In order to explore the diagnostic value of parallel tests, this study prospectively enrolled 258 patients with smear-negative PTB from May 2, 2015 to December 31, 2016. The sputum specimens and bronchial alveolar lavage fluid (BALF) samples from all patients were assessed for MTB detection by culture, Xpert MTB/RIF, and simultaneous amplification and testing method for TB (SAT-TB). Overall, the sensitivity of any single test using culture, Xpert MTB/RIF, or SAT-TB was lower than that for parallel tests (p < 0.05), and the sensitivity rates for MTB detection in BALF were significantly higher than those in sputum samples. There were lower agreements in the detection results between sputum samples and BALF for all tests (p < 0.05). The parallel tests models of using culture plus Xpert MTB/RIF plus SAT-TB, culture plus Xpert, or culture plus SAT-TB achieved higher sensitivities compared with all three single test models (p < 0.05). Additionally, joint detection using sputum and BALF samples achieved a high sensitivity (0.8566, 95% CI: 0.8086–0.8941). In conclusion, the parallel tests model using culture, Xpert MTB/RIF, and SAT-TB in sputum plus BALF significantly increases the diagnostic performance of smear-negative PTB; thus, this method should be applied clinically when PTB is suspected but smear results are negative.