Effect of Bedaquiline and Delamanid Pharmacokinetics on Sputum Culture Conversion and Adverse Events in Drug-Resistant Tuberculosis

BACKGROUND

Pharmacokinetic studies of bedaquiline and delamanid in patients with pre-extensively drug-resistant tuberculosis (pre-XDR TB) will help in the optimization of these drugs for both culture conversion and adverse events.

METHODS

A prospective cohort of 165 adult patients (56% male with mean [SD] age 29 [9.7] years) with pre-XDR TB was treated with bedaquiline, delamanid, clofazimine, and linezolid for 24 weeks at 5 sites in India. Bedaquiline was administered at 400 mg daily for 2 weeks followed by 200 mg thrice weekly for 22 weeks, whereas delamanid was administered at 100 mg twice daily. In 23 consenting participants at 8 and 16 weeks of treatment, blood was collected at 0, 2, 4, 5, 6, 8, 12, and 24 hours postdosing for an intense pharmacokinetic study. Pharmacokinetic parameters were correlated with sputum culture conversion and adverse events.

RESULTS

The mean (SD) age and weight of patients were 30 (10) years and 54 kg, respectively. The median minimum concentration (Cmin) and time-concentration curve (AUC) for bedaquiline, respectively, were 0.6 mcg/mL and 27 mcg/mL·h at week 8 and 0.8 mcg/mL and 36 mcg/mL·h at week 16, suggesting drug accumulation over time. The median Cmin and AUC of delamanid, respectively, were 0.17 mcg/mL and 5.1 mcg/mL·h at week 8 and 0.20 mcg/mL and 7.5 mcg/mL·h at week 16. Delay in sputum conversion was observed in patients with drug concentrations lower than the targeted concentration. At weeks 8 and 16, 13 adverse events were observed. Adverse events were resolved through symptomatic treatment. Body mass index was found to be significantly associated with drug-exposure parameters.

CONCLUSIONS

Bedaquiline and delamanid when co-administered exhibit plasma drug levels within the targeted concentrations, showing an exposure-response relationship.

Linezolid Pharmacokinetics and Its Association with Adverse Drug Reactions in Patients with Drug-Resistant Pulmonary Tuberculosis

We evaluated the relationship between the pharmacokinetic parameters of linezolid (LZD) and development of adverse drug reactions (ADRs) in patients with pulmonary drug-resistant tuberculosis. A prospective cohort of adults with pulmonary multidrug-resistant tuberculosis with additional resistance to fluoroquinolone (MDR-TB_FQ+) received treatment with bedaquiline, delamanid, clofazimine, and LZD. Blood samples were collected during weeks 8 and 16 at eight time points over 24 h. The pharmacokinetic parameters of LZD were measured using high-performance liquid chromatography and associated with ADRs. Of the 165 MDR-TB_FQ+ patients on treatment, 78 patients developed LZD-associated anemia and 69 developed peripheral neuropathy. Twenty-three patients underwent intense pharmacokinetic testing. Plasma median trough concentration was 2.08 µg/mL and 3.41 µg/mL, (normal <2 µg/mL) and AUC_0-24 was 184.5 µg/h/mL and 240.5 µg/h/mL at weeks 8 and 16, respectively, showing a linear relationship between duration of intake and plasma levels. Nineteen patients showed LZD-associated ADRs-nine at week 8, twelve at week 16, and two at both weeks 8 and 16. Thirteen of the nineteen had high plasma trough and peak concentrations of LZD. A strong association between LZD-associated ADRs and plasma LZD levels was noted. Trough concentration alone or combinations of trough with peak levels are potential targets for therapeutic drug monitoring.