Intrapulmonary Pharmacokinetics of First-line Anti-tuberculosis Drugs in Malawian Patients With Tuberculosis

McCallum, Andrew, Pertinez, Henry E, Else, Laura J, Dilly-Penchala, Sujan, Chirambo, Aaron P, Sheha, Irene, Chasweka, Madalitso, Chitani, Alex, Malamba, Rose D, Meghji, Jamilah ORCID: https://orcid.org/0000-0002-4693-8884, Gordon, Stephen ORCID: https://orcid.org/0000-0001-6576-1116, Davies, Geraint R, Khoo, Saye H, Sloan, Derek and Mwandumba, Henry ORCID: https://orcid.org/0000-0003-4470-3608 (2021) 'Intrapulmonary Pharmacokinetics of First-line Anti-tuberculosis Drugs in Malawian Patients With Tuberculosis'. Clinical Infectious Diseases, Vol 73, Issue 9, pp. 3365-3373.

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Abstract

BACKGROUND: Further work is required to understand the intrapulmonary pharmacokinetics of first-line anti-tuberculosis drugs. This study aimed to describe the plasma and intrapulmonary pharmacokinetics of rifampicin, isoniazid, pyrazinamide, and ethambutol, and explore relationships with clinical treatment outcomes in patients with pulmonary tuberculosis.

METHODS: Malawian adults with a first presentation of microbiologically-confirmed pulmonary tuberculosis received standard 6-month first-line therapy. Plasma and intrapulmonary samples were collected 8 and 16 weeks into treatment and drug concentrations measured in plasma, lung/airway epithelial lining fluid, and alveolar cells. Population pharmacokinetic modelling generated estimates of drug exposure (Cmax and AUC) from individual-level post-hoc Bayesian estimates of plasma and intrapulmonary pharmacokinetics.

RESULTS: One-hundred-and-fifty-seven patients (58% HIV co-infected) participated. Despite standard weight-based dosing, peak plasma concentrations of first-line drugs were below therapeutic drug monitoring targets. Rifampicin concentrations were low in all three compartments. Isoniazid, pyrazinamide, and ethambutol achieved higher concentrations in epithelial lining fluid and alveolar cells than plasma. Isoniazid and pyrazinamide concentrations were 14.6 (95% CI: 11.2-18.0) and 49.8-fold (95% CI: 34.2-65.3) higher in lining fluid than plasma respectively. Ethambutol concentrations were highest in alveolar cells (alveolar cells:plasma ratio 15.0, 95% CI 11.4-18.6). Plasma or intrapulmonary pharmacokinetics did not predict clinical treatment response.

CONCLUSIONS: We report differential drug concentrations between plasma and the lung. While plasma concentrations were below therapeutic monitoring targets, accumulation of drugs at the site of disease may explain the success of the first-line regimen. The low rifampicin concentrations observed in all compartments lend strong support for ongoing clinical trials of high-dose rifampicin regimens.

Item Type:	Article
Subjects:	QV Pharmacology > Anti-Inflammatory Agents. Anti-Infective Agents. Antineoplastic Agents > QV 268 Antitubercular agents. Antitubercular antibiotics WA Public Health > Health Problems of Special Population Groups > WA 395 Health in developing countries WF Respiratory System > Tuberculosis > WF 200 Tuberculosis (General) WF Respiratory System > Tuberculosis > WF 300 Pulmonary tuberculosis WF Respiratory System > Tuberculosis > WF 310 Therapy WF Respiratory System > Tuberculosis > WF 360 Drug therapy
Faculty: Department:	Clinical Sciences & International Health > Clinical Sciences Department
Digital Object Identifer (DOI):	https://doi.org/10.1093/cid/ciaa1265
Depositing User:	Julie Franco
Date Deposited:	03 Sep 2020 14:02
Last Modified:	04 Nov 2021 11:51
URI:	https://archive.lstmed.ac.uk/id/eprint/15277

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