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Importance of Ethnicity, CYP2B6 and ABCB1 Genotype for Efavirenz Pharmacokinetics and Treatment Outcomes: a Parallel-group Prospective Cohort Study in Two Sub-Saharan Africa Populations

Abstract

Objectives: We evaluated the importance of ethnicity and pharmacogenetic variations in determining efavirenz pharmacokinetics, auto-induction and immunological outcomes in two African populations.

Methods: ART naïve HIV patients from Ethiopia (n = 285) and Tanzania (n = 209) were prospectively enrolled in parallel to start efavirenz based HAART. CD4+ cell counts were determined at baseline, 12, 24 and 48 weeks. Plasma and intracellular efavirenz and 8-hydroxyefvairenz concentrations were determined at week 4 and 16. Genotyping for common functional CYP2B6, CYP3A5, ABCB1, UGT2B7 and SLCO1B1 variant alleles were done.

Result: Patient country, CYP2B6*6 and ABCB1 c.4036A>G (rs3842A>G) genotype were significant predictors of plasma and intracellular efavirenz concentration. CYP2B6*6 and ABCB1 c.4036A>G (rs3842) genotype were significantly associated with higher plasma efavirenz concentration and their allele frequencies were significantly higher in Tanzanians than Ethiopians. Tanzanians displayed significantly higher efavirenz plasma concentration at week 4 (p<0.0002) and week 16 (p = 0.006) compared to Ethiopians. Efavirenz plasma concentrations remained significantly higher in Tanzanians even after controlling for the effect of CYP2B6*6 and ABCB1 c.4036A>G genotype. Within country analyses indicated a significant decrease in the mean plasma efavirenz concentration by week 16 compared to week 4 in Tanzanians (p = 0.006), whereas no significant differences in plasma concentration over time was observed in Ethiopians (p = 0.84). Intracellular efavirenz concentration and patient country were significant predictors of CD4 gain during HAART.

Conclusion: We report substantial differences in efavirenz pharmacokinetics, extent of auto-induction and immunologic recovery between Ethiopian and Tanzanian HIV patients, partly but not solely, due to pharmacogenetic variations. The observed inter-ethnic variations in efavirenz plasma exposure may possibly result in varying clinical treatment outcome or adverse event profiles between populations.

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References
1.
Ngaimisi E, Mugusi S, Minzi O, Sasi P, Riedel K, Suda A . Long-term efavirenz autoinduction and its effect on plasma exposure in HIV patients. Clin Pharmacol Ther. 2010; 88(5):676-84. DOI: 10.1038/clpt.2010.172. View

2.
Tsegaye A, Messele T, Tilahun T, Hailu E, Sahlu T, Doorly R . Immunohematological reference ranges for adult Ethiopians. Clin Diagn Lab Immunol. 1999; 6(3):410-4. PMC: 103732. DOI: 10.1128/CDLI.6.3.410-414.1999. View

3.
Elens L, Vandercam B, Yombi J, Lison D, Wallemacq P, Haufroid V . Influence of host genetic factors on efavirenz plasma and intracellular pharmacokinetics in HIV-1-infected patients. Pharmacogenomics. 2010; 11(9):1223-34. DOI: 10.2217/pgs.10.94. View

4.
Heil S, van der Ende M, Schenk P, van der Heiden I, Lindemans J, Burger D . Associations between ABCB1, CYP2A6, CYP2B6, CYP2D6, and CYP3A5 alleles in relation to efavirenz and nevirapine pharmacokinetics in HIV-infected individuals. Ther Drug Monit. 2012; 34(2):153-9. DOI: 10.1097/FTD.0b013e31824868f3. View

5.
Habtewold A, Amogne W, Makonnen E, Yimer G, Riedel K, Ueda N . Long-term effect of efavirenz autoinduction on plasma/peripheral blood mononuclear cell drug exposure and CD4 count is influenced by UGT2B7 and CYP2B6 genotypes among HIV patients. J Antimicrob Chemother. 2011; 66(10):2350-61. DOI: 10.1093/jac/dkr304. View