The Safety, Effectiveness and Concentrations of Adjusted Lopinavir/Ritonavir in HIV-Infected Adults on Rifampicin-Based Antitubercular Therapy

Rifampicin co-administration dramatically reduces plasma lopinavir concentrations. Studies in healthy volunteers and HIV-infected patients showed that doubling the dose of lopinavir/ritonavir (LPV/r) or adding additional ritonavir offsets this interaction. However, high rates of hepatotoxicity were observed in healthy volunteers. We evaluated the safety, effectiveness and pre-dose concentrations of adjusted doses of LPV/r in HIV infected adults treated with rifampicin-based tuberculosis treatment.Adult patients on a LPV/r-based antiretroviral regimen and rifampicin-based tuberculosis therapy were enrolled. Doubled doses of LPV/r or an additional 300 mg of ritonavir were used to overcome the inducing effect of rifampicin. Steady-state lopinavir pre-dose concentrations were evaluated every second month.18 patients were enrolled with a total of 79 patient months of observation. 11/18 patients were followed up until tuberculosis treatment completion. During tuberculosis treatment, the median (IQR) pre-dose lopinavir concentration was 6.8 (1.1-9.2) mg/L and 36/47 (77%) were above the recommended trough concentration of 1 mg/L. Treatment was generally well tolerated with no grade 3 or 4 toxicity: 8 patients developed grade 1 or 2 transaminase elevation, 1 patient defaulted additional ritonavir due to nausea and 1 patient developed diarrhea requiring dose reduction. Viral loads after tuberculosis treatment were available for 11 patients and 10 were undetectable.Once established on treatment, adjusted doses of LPV/r co-administered with rifampicin-based tuberculosis treatment were tolerated and LPV pre-dose concentrations were adequate

The relation between treatment outcome and efavirenz, atazanavir or lopinavir exposure in the NORTHIV trial of treatment-na

The relation between treatment outcome and trough plasma concentrations of efavirenz (EFV), atazanavir (ATV) and lopinavir (LPV) was studied in a pharmacokinetic/pharmacodynamic substudy of the NORTHIV trial-a randomised phase IV efficacy trial comparing antiretroviral-na < ve human immunodeficiency virus-1-infected patients treated with (1) EFV + 2 nucleoside reverse transcriptase inhibitors (2NRTI) once daily, (2) ritonavir-boosted ATV + 2NRTI once daily or (3) ritonavir-boosted LPV + 2NRTI twice daily. The findings were related to the generally cited minimum effective concentration levels for the respective drugs (EFV 1,000 ng/ml, ATV 150 ng/ml, LPV 1,000 ng/ml). The relation between atazanavir-induced hyperbilirubinemia and virological efficacy was also studied. Drug concentrations were sampled at weeks 4 and 48 and optionally at week 12 and analysed by high-performance liquid chromatography with UV detector. When necessary, trough values were imputed by assuming the reported average half-lives for the respective drugs. Outcomes up to week 48 are reported. No relation between plasma concentrations of EFV, ATV or LPV and virological failure, treatment withdrawal due to adverse effects or antiviral potency (viral load decline from baseline to week 4) was demonstrated. Very few samples were below the suggested minimum efficacy cut-offs, and their predictive value for treatment failure could not be validated. There was a trend toward an increased risk of virological failure in patients on ATV who had an average increase of serum bilirubin from baseline of < 25 mu mol/l. The great majority of treatment-na < ve and adherent patients on standard doses of EFV, ritonavir-boosted ATV and ritonavir-boosted LPV have drug concentrations above that considered to deliver the maximum effect for the respective drug. The results do not support the use of routine therapeutic drug monitoring (TDM) for efficacy optimisation in treatment-na < ve patients on these drugs, although TDM may still be of value in some cases of altered pharmacokinetics, adverse events or drug interactions. Serum bilirubin may be a useful marker of adherence to ATV therapy