Efficacy of linezolide-free chemotherapy schemes in patients with highly drug-resistant tuberculosis

The combination of fluoroquinolones (Fq), bedaquiline (Bdq) and linezolid (Lzd) is the basis for the treatment of tuberculosis with extensively and pre-extensively drug-resistant M.&nbsp;tuberculosis (XDR/pre-XDR-TB). However, it is not always possible to form a regimen based on these three drugs. <b>Objective:</b> to evaluate the efficacy of chemotherapy regimens with the inclusion of Bdq and Fq without Lzd in XDR/pre-XDR-TB patients. <b>Materials and Methods:</b> A prospective observational study was conducted, which involved 34 patients: 23 with XDR-TB and 11 with pre-XDR-TB. All patients had a history of treatment failure and disease progression. Caseous pneumonia and chronic TB were observed in 8.8% and 47.1% of patients. The duration of Bdq use was 24 weeks, the overall course of chemotherapy was on average 20±2 months. The frequency of use of chemotherapy drugs: Bdq – 100%; Fq – 100%; cycloserine/terizidone – 82.4%; prothionamide – 79.4%; pyrazinamide – 76.5%; capreomycin – 47.1%; ethambutol – 35.6%; PAS – 20.6%; amikacin – 14.7%. <b>Results:</b> The efficacy of chemotherapy at 24 weeks: culture conversion from positive to negative confirmed by bacterioscopy – 76.5% [95%CI 58.8-89.3%] patients; culture method - 70.6% [95%CI 52.5-84.9%]; improvement of X-ray findings – 73.5% [95%CI 55.6-87.1%]; normalization of complete blood count – 76.5% [95%CI 58.8-89.3%] patients. At 20±2 months, 64.7% [95%CI 46.5-80.3%] patients had no mycobacteria. <b>Measurements and Main Results:</b> The chemotherapy regimen based on Bdq and Fq, but without Lzd, in XDR/pre-XDR-TB patients with previous unsuccessful courses of treatment, is effective in terms of mycobacteria elimination&nbsp;and is better than this figure among&nbsp;MDR-TB patients in Russia/