Efficacy of using bedaquiline in treatment of tuberculosis patients with multiple and extensive drug resistance

Abstract

The objective: to compare treatment efficacy of pulmonary tuberculosis patients with multiple (MDR) and extensive drug resistance (XDR) using a standard chemotherapy regimen and the regimen containing bedaquiline.Subjects and Methods. A retrospective study was conducted to analyze treatment outcomes in 219 patients with pulmonary tuberculosis and MDR/XDR of Mycobacterium tuberculosis (MTB) aged 18-75 years old who were treated in in-patient and out-patient facilities of St. Petersburg from 2016 to 2019. Treatment outcomes were analyzed by subgroups formed taking into account resistance patterns and addition of bedaquiline to the treatment regimens: Ia – n = 94 (MDR TB; Bq-) and IIa ‒ n = 80 (XDR TB; Bq-); Ib ‒ n = 22 (MDR TB; Bq+) and IIb ‒ n = 23 (XDR TB; Bq+). Clinical and laboratory parameters of patients, the severity of comorbidity were assessed before the start of treatment, after 3, 6, 12-14 and 18-24 months of therapy, as well as after therapy completion and during the follow-up period. Statistical analysis was carried out using Statistica 10.0 and methods of parametric and nonparametric statistics and the SPSS 16.0 software, where p ≤ 0.05 was considered significant.Results. XDR TB patients in Subgroup IIb were significantly more likely to have a high level of comorbidity according to Charlson index (from 5 to 6 points) – in 34.7% of cases versus 5.0% in Subgroup IIa. At all stages of treatment in MDR TB patients with Bq+ (Ib), sputum conversion was recorded significantly more often versus patients of Subgroup Ia with Bq- when examined at all stages, with maximum effectiveness achieved by 18-24 months of treatment (90.9%). Treatment efficacy of XDR TB patients (IIb, Bq+) was also significantly higher versus treatment regimen containing no bedaquiline (60.8% (IIb, Bq+) versus 25.0% (IIa, Bq-), χ2 = 4.61, p < 0.05).Conclusions. Achieved high efficacy of therapy in Subgroups Ib and IIb containing Bq provided a positive impact on treatment default rates, that were recorded in a low percentage of cases in those subgroups. An ineffective course of treatment in MDR TB patients treated with regimens containing no Bq was observed in 42.5% in Subgroup Ia, while this rate made only 0.09% in Subgroup Ib. Treatment effectiveness was the highest in XDR TB patients of Subgroup IIb when Bq was added to the treatment regimen.