The risk of ineffective MDR/XDR TB treatment, based on bedaquilin: factors and their influence

<b>Background:</b> The treatment regimens, based on bedaquiline (Bdq), linezolid (Lz), levo-/moxifloxacin (Lev/Mox), are now the preferable for MDR TB treatment (WHO, 2019). But some aspects of their realization are not clear enough. The selection of the patients with the high risk of ineffective treatment (IT) is one of the most important clinical problem. <b>Materials and Methods:</b> 315 patients, included in the study, received chemotherapy based on Bdq, Lz, Lev/Mox, cycloserine/terizidone with 2-3 additional antituberculosis drugs. At the end of 24th month of treatment/follow up the treatment success registered in 248 (78.7%) and other outcomes, definite as IT – in 67 (21.3%, include death in 22 pts – 7.0%). The analyses used mono- (by odds ratio – OR) and multivariable (by logistic regression) approaches. <b>Results:</b> Single-variable analysis showed the most related with IT risk factors from 4 groups: patients’ social, behavioral and medical characteristics (1), MBT drug resistance (2), parameters of TB process (3), chemotherapy regimens (4). The number of significantly related with IT factors exceed 20. But the multivariable analysis identified only 4 independently statistically-significant factors for IT: MIC Bdq for MBT on Middlebrook 7H11 &gt; 0,06 мкг/ml OR for IT 10.7 (95%CI 2.4-47.9, p = 0.002), low treatment adherence – OR 7.9 (3.4-18.0, p &lt; 0.001), alcohol abuse – OR 2.7 (1.2-6.1, p = 0,017) and ineffective previously TB treatment duration more than one year – OR 2.6 (1.1-6.3, p = 0.03). <b>Conclusion:</b> The new chemotherapy regimens’ effectiveness not depend on the MBT drug resistance spectrum (exclude Bdq), but factors, related to patients’ behavior, retain their value.