LAUSR

Background To evaluate the pharmacokinetic of plasma lopinavir (LPV) and ritonavir (RTV) when co-administered with three times weekly (TPW) rifabutin (RBT) at a dose of either 150 or 300 mg in African tuberculosis (TB) and HIV co-infected adult patients. Methods This is a pharmacokinetic study conducted in Ouagadougou among patients treated with a standard dosage of LPV/RTV 400/100 mg twice daily and RBT 150 mg TPW (arm A = 9 patients) or rifabutin 300 mg TPW (arm B = 7 patients) based regimens. Patients were recruited from the Bogodogo and Kossodo district hospitals in Ouagadougou from May 2013 to December 2015. Study inclusion criteria were that the patients were between 18 and 60 years of age, HIV-1 infected with pulmonary tuberculosis confirmed or suspected. Subsequent blood samples for pharmacokinetic monitoring were collected at 1, 2, 3, 4, 6, 8 and 12 h after combined drug ingestion for plasma drug monitoring using HPLC/MS assays. Results The medians LPV C max and T max were respectively, 20 μg/mL and 4 h for the RBT 150 mg group (arm A) and 7.7 μg/mL and 3 h for the RBT 300 mg group (arm B). The AUC 0–12 of LPV was 111.8 μg h/mL in patients belonging to arm A versus 69.9 μg/mL for those in arm B (p = 0.313). The C 0 of LPV was lower than 4 μg/mL in three patients receiving RBT 300 mg. Of note, the RTV plasma concentrations were nearly halved among patients on RBT 300 mg compared to those on lower RBT doses. The AUC 0–12 of RTV in arm A was 12.7 μg h/mL versus 6.6 μg h/ml in arm B (p = 0.313). Conclusion In our study, the pharmacokinetic of LPV and RTV was found to be highly variable when coadministrated with RBT 150 mg or 300 mg three times per week. There is a need for specific large study to verify clinical and virological effects of this variation, especially when coadministrated with RBT of 300 mg TPW, and to prevent viral resistance in response to under-dosing of LPV. Trial registration PACTR201310000629390. Registered 28 October 2013, http://www.pactr.org/