The safety and efficacy of different anti-tuberculosis regimens containing Lzd for RR/MDR/Pre-XDR-TB patients in China.

China remains a high-burden country for rifampicin-resistant tuberculosis. The treatment of drug-resistant tuberculosis is expensive, with many adverse drug reactions and greater difficulty to cure. Searching for appropriate treatment regimens is urgent. A retrospective study was conducted on HIV-negative patients aged 18 to 60 years with rifampicin- or multidrug- or pre-extensively drug-resistant tuberculosis (RR/MDR/Pre-XDR-TB) at the Public Health Clinical Center of Chengdu, China from May 1, 2018 to July 31, 2022. Patients were divided into 3 groups: linezolid (Lzd) + bedaquiline (Bdq) containing group (regimen A), Lzd + delamanid (Dlm) containing group (regimen B), and Lzd + other drugs containing group (regimen C, not containing Bdq or Dlm). A total of 142 RR/MDR/Pre-XDR-TB patients were included (63 in regimen A, 34 in regimen B, and 45 in regimen C). At 2 months of treatment, 1 patient was lost to follow-up in regimen A and regimen C, respectively. At 6 months of treatment, 3 patients were lost to follow-up in regimen A and regimen C, respectively, and 2 patients were lost to follow-up in regimen B. The sputum culture conversion rates of RR/MDR/Pre-XDR-TB patients in regimen A, B, and C at the end of 2 and 6 months were (72.6% [45/62] vs 64.7% [22/34] vs 18.2% [8/44]) and (95.0% [57/60] vs 90.6% [29/32] vs 81.0% [34/42]), respectively (P < .05). 88.2% (30/34) of the Dlm group used Lzd-Dlm-clofazimine (Cfz)-cycloserine (Cs) containing regimens. 7.9% (5/63) of patients stopped using Bdq due to corrected QT interval by Fredericia >500 ms. 2.9% (1/34) of patients with corrected QT interval by Fredericia prolongation and an increase of 88 ms from baseline stopped Dlm. No patient experienced any malignant heart disease events. Due to related adverse events of Lzd, 14.1% (20/142) reduced Lzd dosage and 6.3% (9/142) had permanent discontinuation of Lzd. 6-month Lzd + (Bdq or Dlm) containing regimens were associated with favorable early culture conversion and showed good safety among HIV-negative patients aged 18 to 60 years with RR/MDR/Pre-XDR-TB. Lzd-Dlm-Cfz-Cs containing regimens may serve as promising candidate regimens for future research on rifampicin-resistant tuberculosis. Multicenter prospective studies with longer follow-up and definitive treatment outcomes are needed to establish comparative effectiveness or treatment superiority of these regimens.