Linezolid use for drug-resistant tuberculosis in Georgia: a retrospective cohort study

Impact of Prior Tuberculosis Treatment With New/Companion Drugs on Clinical Outcomes in Patients Receiving Concomitant Bedaquiline and Delamanid for Multidrug- and Rifampicin-Resistant Tuberculosis

BACKGROUND

There are scarce data on the clinical outcomes of persons retreated with new/companion anti-tuberculosis (TB) drugs for multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). We sought to evaluate the efficacy and safety of bedaquiline and delamanid containing regimens among patients with and without prior exposure to the new/companion drugs (bedaquiline, delamanid, linezolid, clofazimine, and fluoroquinolones).

METHODS

We conducted a retrospective cohort study among patients with pulmonary MDR/RR-TB in Georgia who received bedaquiline and delamanid combination as a part of a salvage regimen from November 2017 to December 2020 in a programmatic setting.

RESULTS

Among 106 persons with a median age of 39.5 years, 44 (41.5%) were previously treated with new/companion TB drugs. Patients with prior exposure to new/companion drugs had higher rates of baseline resistance compared to those without exposure to new/companion TB drugs (bedaquiline 15.2% vs 1.8%, linezolid 22.2% vs 16.7%). Sputum culture conversion rates among patients exposed and not exposed to new/companion drugs were 65.9% vs 98.0%, respectively (P < .001). Among patients with and without prior new/companion TB drug use, favorable outcome rates were 41.0% and 82.3%, respectively (P < .001). Treatment adherence in 32 (30.2%) patients was ≤80%. Five of 21 patients (23.8%) who had a baseline and repeat susceptibility test had acquired bedaquiline resistance. QTC/F prolongation (>500 ms) was rare (2.8%).

CONCLUSIONS

Prior exposure to new/companion TB drugs was associated with poor clinical outcomes and acquired drug resistance. Tailoring the TB regimen to each patient's drug susceptibility test results and burden of disease and enhancing adherence support may improve outcomes.

Adverse drug reactions due to linezolid in the programmatic management of drug-resistant tuberculosis in India: A retrospective multicenter study

BACKGROUND

Monitoring and managing adverse drug reactions (ADR) are critical for treating drug-resistant tuberculosis (TB).

OBJECTIVE

To study symptomatic, linezolid-attributable ADRs in TB patients initiated on all oral longer bedaquiline-based treatment regime for multidrug-resistant/rifampicin-resistant (MDR/RR)-TB under programmatic conditions.

METHODS

It was a multicenter, retrospective study of people with MDR/RR-TB in nine TB units in Nagpur, India, from March 2020 to April 2022.

RESULTS

The study consisted of a sample size of 106 individuals with multidrug-resistant and rifampicin-resistant tuberculosis out of a total of 110 individuals with the disease. Of these, 45 (42.45%) experienced linezolid ADRs, with an incidence of 11.37 cases per 1000 person-weeks. These patients were significantly younger (31.24 ± 11.13 years) and more likely to be female (27, 50%) than those without ADRs. ADR severity was mild in 20 (44.45%), moderate in 15 (33.33%), and severe in 10 (22.22%) patients. The most common ADR was peripheral neuropathy (42, 93.33%), followed by lactic acidosis (3, 6.67%), anemia (2, 4.44%), and optic neuritis (2, 4.44%). Dosing was reduced in 17 (37.78%) patients, and linezolid was withdrawn entirely in 19 (42.22%) patients. Only 9 (20%) patients continued linezolid unmodified. For mild to moderate linezolid-associated symptomatic peripheral neuropathy, symptom management with or without dose reduction is an effective strategy; however, immediate linezolid withdrawal is necessary in severe or life-threatening peripheral neuropathy cases. After a mean follow-up of 41 ± 21.33 weeks, ADR symptoms resolved completely in 4 (6.67%) patients and decreased in 42 (93.33%) patients.

CONCLUSION

Linezolid ADRs, often neuropathy, frequently occur in patients on an all-oral bedaquiline-based treatment regime for MDR/RR-TB. Women and younger patients are more likely to experience these ADRs, usually mild to moderate in severity. Management of symptomatic linezolid-associated peripheral neuropathy should be based on ADR severity. These ADRs often affect linezolid dosing, so it is important to identify and manage them early.

Linezolid-related adverse effects in the treatment of rifampicin resistant tuberculosis: a retrospective study

Linezolid (LZD) is an effective drug in treating multidrug-resistant tuberculosis and extensively drug-resistant tuberculosis. This study aimed to evaluate the safety of LZD in the treatment of patients with rifampicin resistant tuberculosis. This was a multicenter retrospective study. A total of 184 patients of the rifampicin resistant tuberculosis patients treated with LZD from Jan 2018 to Apr 2020 in three hospitals were involved, and their clinical symptoms were recorded and analyzed. Meanwhile, the types and incidence of adverse effects associated with LZD were evaluated. It showed that peripheral neuritis (51, 27.7%) and hemochromatosis (42, 22.8%) were the most common adverse effects observed among these patients. The median time of symptoms after LZD treatment was 45.5 and 120.0 days, respectively. Furthermore, female patients had a significantly higher risk for leukopenia (P = 0.002) and hemochromatosis (P = 0.033) when compared with male patients. History of underlying disease was the risk factor for thrombocytopenia (P = 0.022). Patients with long duration of medication (RR = 1.004, 95%CI: 1.002-1.006, P < 0.001) and daily dosage ≥600mg (RR = 3.059, 95%CI: 1.238-7.558, P = 0.015) were at higher risk of hemochromatosis. Age was the risk factor for rash (P = 0.008) and nausea and vomiting (P = 0.018). In addition, LZD administration time was the risk factor for optic neuritis (P < 0.001) and peripheral neuritis (P < 0.001). LZD can cause adverse symptoms in patients with rifampicin resistant tuberculosis. Gender, history of underlying disease, LZD use time, LZD dosage, and age are the risk factors in the LZD treatment of these patients. During medication, bone marrow suppression and neuropathy should be closely monitored. This study could potentially provide useful information for the clinical practice.

Linezolid Exposure Is Associated with Cytopenias in Patients Treated for Multidrug-Resistant Tuberculosis

Although linezolid is effective for multidrug-resistant TB (MDR-TB) tuberculosis treatment, it is associated with cytopenias after 4 weeks of administration. Data on toxicities with long-term use of linezolid and drug pharmacodynamics in MDR-TB treatment are limited, and concerns about toxicity present barriers to wider implementation. This was a secondary analysis of a prospective cohort study of patients treated for MDR-TB in the country of Georgia from 2015 to 2017. Intensive blood sampling 4 to 6 weeks after treatment initiation with linezolid 600 mg daily was performed for pharmacokinetic (PK) analysis, including linezolid trough concentration (Cmin) and area under the curve from 0 to 24 hours (AUC0-24). Linezolid exposure was defined using literature-reported thresholds. Cytopenias were defined using an NIH adverse event (AE) scale. Logistic regression was used to evaluate the relationship between linezolid exposure and cytopenias. Among 76 patients receiving linezolid in their baseline treatment regimen and who had PK data available, cytopenia AEs occurred in 30 (39.5%) for an incidence rate of 46 per 100 person-years. The median duration of linezolid therapy was 526 days. No patients required dose reduction or interruption due to cytopenias. Median linezolid Cmin was 0.235 mg/L (interquartile range [IQR], 0.069 to 0.529), and median AUC0-24 was 89.6 mg·h/L (IQR, 69.2 to 116.2). Cytopenias were associated with linezolid PK parameters (Cmin > 2 mg/L and AUC0-24 > 160 mg·h/L). Cytopenias occurred frequently with long-term use of linezolid 600 mg/day and were associated with PK parameters but did not result in the need for treatment interruption in the management of a cohort of patients with MDR-TB.

Bedaquiline, Delamanid, Linezolid and Clofazimine for Treatment of Pre-extensively Drug-Resistant Tuberculosis

BACKGROUND

Treatment success rates for multidrug-resistant tuberculosis (MDR-TB) remain low globally. Availability of newer drugs has given scope to develop regimens that can be patient-friendly, less toxic, with improved outcomes. We proposed to determine the effectiveness of an entirely oral, short-course regimen with Bedaquiline and Delamanid in treating MDR-TB with additional resistance to fluoroquinolones (MDR-TBFQ+) or second-line injectable (MDR-TBSLI+).

METHODS

We prospectively determined the effectiveness and safety of combining two new drugs with two repurposed drugs - Bedaquiline, Delamanid, Linezolid, and Clofazimine for 24-36 weeks in adults with pulmonary MDR-TBFQ+ or/and MDR-TBSLI+. The primary outcome was a favorable response at end of treatment, defined as two consecutive negative cultures taken four weeks apart. The unfavorable outcomes included bacteriologic or clinical failure during treatment period.

RESULTS

Of the 165 participants enrolled, 158 had MDR-TBFQ+. At the end of treatment, after excluding 12 patients due to baseline drug susceptibility and culture negatives, 139 of 153 patients (91%) had a favorable outcome. Fourteen patients (9%) had unfavorable outcomes: four deaths, seven treatment changes, two bacteriological failures, and one withdrawal. During treatment, 85 patients (52%) developed myelosuppression, 69 (42%) reported peripheral neuropathy, and none had QTc(F) prolongation >500msec. At 48 weeks of follow-up, 131 patients showed sustained treatment success with the resolution of adverse events in the majority.

CONCLUSION

After 24-36 weeks of treatment, this regimen resulted in a satisfactory favorable outcome in pulmonary MDR-TB patients with additional drug resistance. Cardiotoxicity was minimal, and myelosuppression, while common, was detected early and treated successfully.

Supra-therapeutic Linezolid Trough Concentrations in Elderly Patients: A Call for Action?

BACKGROUND AND OBJECTIVE

According to the drug label, linezolid dosage adjustments are not needed in geriatric patients. Nevertheless, clinical evidence suggests that elderly patients may benefit from the use of reduced linezolid doses to limit drug overexposure. Here, we aimed to describe the results of the last 5 years of therapeutic drug monitoring of linezolid in our institution with a special focus on elderly patients.

METHODS

Linezolid therapeutic drug monitoring requests collected between January 2016 and June 2020 were considered. Linezolid trough concentrations were considered both as a continuous variable and as a categorical variable, clustering data according to the therapeutic range proposed by available literature (< 2, 2-8, and > 8 mg/L, respectively). Patients' age and sex were considered as categorical variables. Comparisons of linezolid trough concentrations between groups of patients stratified according to age were performed using an analysis of variance; comparisons in the frequency distributions were performed using the chi-squared test.

RESULTS

From 2016 to 2020, we collected 3250 linezolid TDM requests. A highly significant, progressive increment in the linezolid trough concentrations was observed moving from patients aged < 50 years (5.8 ± 5.6 mg/L) to those aged > 90 years (16.6 ± 10.0 mg/L), with an overall increment of 30% per decade of age. Nearly 30%, 50%, and 65% of patients aged < 65 years, 65-80 years, and > 80 years, respectively, had supra-therapeutic linezolid trough concentrations at the first therapeutic drug monitoring assessment. This trend did not change significantly moving from 2016 to 2020.

CONCLUSIONS

Elderly patients given linezolid at the conventional 600-mg twice-daily dose might be at a high risk of being overexposed to treatment, eventually increasing their risk to experience drug-related hematological toxicity. Reduced linezolid dosing schemes should be potentially considered in elderly patients at a low risk of treatment failure, ideally guided by therapeutic drug monitoring.