<p>Inter-individual variability in efavirenz (EFV) pharmacokinetics and dynamics is dominantly driven by the polymorphism in cytochrome P450 (CYP) isoenzyme 2B6 516G&gt;T. We hypothesized that additional CYP polymorphisms mediate the relationship between CYP2B6 516G&gt;T, EFV metabolism, and clinical events. We investigated 21 SNPs in 814 HIV-infected adults initiating EFV-based therapy in Botswana for population pharmacokinetics, CNS toxicities, and treatment outcomes. Two SNPs (rs28399499 and rs28399433) showed reduced apparent oral EFV clearance. Four SNPs (rs2279345, rs4803417, rs4802101, and rs61663607) showed extensive clearance. Composite CYP2B-mediated EFV metabolism was significantly associated with CNS toxicity (p = 0.04), with extensive metabolizers reporting more and slow and very slow metabolizers reporting less toxicity after 1 month compared to intermediate metabolizers. Composite CYP2B6 metabolism was not associated with composite early treatment failure. In conclusion, our data suggest that CNS-related toxicities might not be solely the result of super-therapeutic parent EFV concentrations in HIV-infected individuals in patients of African ancestry.</p>

<p><strong>AIMS: </strong>To determine alcohol use effect on HIV treatment success and whether alcohol use mediates the relation between male sex and treatment failure.</p>

<p><strong>DESIGN: </strong>Longitudinal cohort study.</p>

<p><strong>SETTING: </strong>Eight HIV clinics in and near Gaborone, Botswana.</p>

<p><strong>PARTICIPANTS: </strong>A total of 938 HIV-infected treatment-naive adults initiating regimens containing the antiretroviral medication efavirenz between June 2009 and February 2013, including 478 (51%) males, median age 38&nbsp;years, and plasma HIV RNA 4.9 logcopies/ml.</p>

<p><strong>MEASUREMENTS: </strong>Primary outcome was a composite of treatment failure over 6&nbsp;months including death, lost to care or plasma HIV RNA &gt; 25 copies/ml. Exposures included alcohol use and gender.</p>

<p><strong>FINDINGS: </strong>Failure in 339 (36%) participants included 40 (4%) deaths, 194 (21%) lost to care and 105 (11%) with HIV RNA&nbsp;&gt;&nbsp;25 copies/ml. Both hazardous alcohol use in the past year [adjusted odds ratio (aOR)&nbsp;=&nbsp;1.4, 95% confidence interval (CI)&nbsp;=&nbsp;1.0, 1.9] and male sex (aOR&nbsp;=&nbsp;2.1, 95% CI&nbsp;=&nbsp;1.5, 2.9) were associated with failure. Hazardous alcohol use in the year prior to enrollment was more common in men (57%) than women (24%), P&nbsp;&lt;&nbsp;0.001. There was no difference in alcohol use effect on failure between sexes (P for interaction&nbsp;&gt;&nbsp;0.5). Controlling for hazardous alcohol use did not change the relation between sex and failure.</p>

<p><strong>CONCLUSION: </strong>Alcohol use among HIV-infected adults in Botswana appears to worsen HIV treatment outcomes. Alcohol use does not appear to have either a mediating or a moderating effect on the relation between gender and HIV treatment outcome failure.</p>

<p><strong>OBJECTIVES: </strong>To determine the association between cytochrome p450 2B6 genotypes and efavirenz-based HIV treatment outcomes.</p>

<p><strong>DESIGN: </strong>Observational cohort study of HIV infected adults initiating efavirenz-based regimens in Botswana.</p>

<p><strong>METHODS: </strong>The primary endpoint was a composite of death or loss to care or HIV RNA&gt;25 copies/ml at 6 months. CYP2B6 516G&gt;T and 983T&gt;C genotyping was done with Taqman Open Array platform. Adverse experiences were measured using the Subject Experience Questionnaire. Metabolism alleles were included in logistic regression models of the composite endpoint.</p>

<p><strong>RESULTS: </strong>801 individuals included 406 (51%) males, median age 37 years, median baseline CD4 count 195 cells/mm and plasma HIV RNA 4·9 log10 copies/ml. 277 (35%) reached the endpoint including 34 (4%) deaths, 151 (19%) lost to care, and 92 (11%) with plasma HIV RNA&gt;25 copies/ml. Metabolism variant alleles were common with 396 (49%) intermediate and 192 (24%) slow metabolizers. There were no statistically significant associations between metabolism and treatment endpoints. However, slower metabolism was associated with fewer adverse experiences.</p>

<p><strong>CONCLUSIONS: </strong>Slow metabolism alleles were associated with lower efavirenz clearance but not any of the treatment endpoints. Slow efavirenz metabolism did not exacerbate CNS toxicity. These results should allay concern that slow efavirenz metabolism adversely impacts individuals in sub-Saharan African settings in which these alleles are common.</p>

<p><strong>BACKGROUND: </strong>CYPB2B6 polymorphisms that affect efavirenz (EFV) concentrations are common, but the effect of this polymorphism on HIV virologic failure in clinical practice settings has not fully been elucidated. Our objective was to investigate the relationship between the CYPB2B6 516G&gt;T genotype and late virologic failure in patients treated with EFV in Gaborone, Botswana.</p>

<p><strong>SETTING: </strong>We performed a case-control study that included 1,338 HIV-infected black Batswana on EFV-based antiretroviral therapy (ART). Patients were approached for enrollment during regular visits at one of the outpatient HIV clinics between 7/2013-4/2014.</p>

<p><strong>METHODS: </strong>Cases experienced late HIV failure, defined as plasma HIV RNA &gt;1000 copies/mL after maintaining viral suppression (&lt;400 copies/mL) for at least 6 months. For each case, a total of 4 control patients were randomly sampled from the same population. Controls had plasma HIV RNA &lt;400 copies/mL on ART for at least 6 months. Logistic regression was used to determine the adjusted odds of late HIV failure by 516G&gt;T genotype.</p>

<p><strong>RESULTS: </strong>After adjustment for the confounding variables age and CD4 count, the CYPB2B6 516 T-allele was protective against late HIV virologic breakthrough, adjusted OR 0.70; 95%CI 0.50-0.97.</p>

<p><strong>CONCLUSION: </strong>The CYPB2B6 516 T-allele was protective against late virologic breakthrough in patients with initial (6 month) HIV RNA suppression on EFV-based ART. Future studies are needed to assess long-term viral benefits of identifying and offering EFV containing ART to black African HIV-infected patients with CYPB2B6 T-alleles, especially given the wider availability of a single pill EFV in this setting.</p>