Early or deferred initiation of efavirenz during rifampicin-based TB therapy has no significant effect on CYP3A induction in TB-HIV infected patients.

Eleni Aklillu, Alimuddin Zumla, Abiy Habtewold, Wondwossen Amogne, Eyasu Makonnen, Getnet Yimer, Jürgen Burhenne, Ulf Diczfalusy

Journal: British journal of pharmacology 2021;178(16):3294-3308

PMID: 33155675

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Abstract

BACKGROUND AND PURPOSE

In TB-HIV co-infection, prompt initiation of TB therapy is recommended but anti-retroviral treatment (ART) is often delayed due to potential drug-drug interactions between rifampicin and efavirenz. In a longitudinal cohort study, we evaluated the effects of efavirenz/rifampicin co-treatment and time of ART initiation on CYP3A induction.

EXPERIMENTAL APPROACH

Treatment-naïve TB-HIV co-infected patients (n = 102) were randomized to efavirenz-based-ART after 4 (n = 69) or 8 weeks (n = 33) of commencing rifampicin-based anti-TB therapy. HIV patients without TB (n = 94) receiving efavirenz-based-ART only were enrolled as control. Plasma 4β-hydroxycholesterol/cholesterol (4β-OHC/Chol) ratio, an endogenous biomarker for CYP3A activity, was determined at baseline, at 4 and 16 weeks of ART.

KEY RESULTS

In patients treated with efavirenz only, median 4β-OHC/Chol ratios increased from baseline by 269% and 275% after 4 and 16 weeks of ART, respectively. In TB-HIV patients, rifampicin only therapy for 4 and 8 weeks increased median 4β-OHC/Chol ratios from baseline by 378% and 576% respectively. After efavirenz/rifampicin co-treatment, 4β-OHC/Chol ratios increased by 560% of baseline (4 weeks) and 456% of baseline (16 weeks). Neither time of ART initiation, sex, genotype nor efavirenz plasma concentration were significant predictors of 4β-OHC/Chol ratios after 4 weeks of efavirenz/rifampicin co-treatment.

CONCLUSION AND IMPLICATIONS

Rifampicin induced CYP3A more potently than efavirenz, with maximum induction occurring within the first 4 weeks of rifampicin therapy. We provide pharmacological evidence that early (4 weeks) or deferred (8 weeks) ART initiation during anti-TB therapy has no significant effect on CYP3A induction.

LINKED ARTICLES

This article is part of a themed issue on Oxysterols, Lifelong Health and Therapeutics. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.16/issuetoc.

Address: Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska University Hospital Huddinge C1:68, Karolinska Institutet, Stockholm, Sweden.; Division of Infection and Immunity, University College London, NIHR Biomedical Research Centre at UCL Hospitals NHS Foundation Trust, London, UK.; UNZA-UCLMS Research and Training Program, Department of Medicine, University Teaching Hospital, Lusaka, Zambia.; Department of Pharmaceutical Sciences, School of Pharmacy, William Carey University, Biloxi, MS, USA.; Department of Internal Medicine, College of Health Science, Addis Ababa University, Addis Ababa, Ethiopia.; Department of Pharmacology, College of Health Sciences, Addis Ababa University, Addis Ababa, Ethiopia.; Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany.; Division of Clinical Chemistry, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital, Stockholm, Sweden.

DOI: 10.1111/bph.15309

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MeSH Terms: Alkynes, Anti-HIV Agents, Benzoxazines, Cyclopropanes, Cytochrome P-450 CYP3A, HIV Infections, Humans, Longitudinal Studies, Rifampin, Tuberculosis