Pharmacogenetics of interaction between depot medroxyprogesterone acetate and efavirenz, rifampicin, and isoniazid during treatment of HIV and tuberculosis.

OBJECTIVE: In AIDS Clinical Trials Group study A5338, concomitant rifampicin, isoniazid, and efavirenz was associated with more rapid plasma medroxyprogesterone acetate (MPA) clearance compared to historical controls without tuberculosis or HIV therapy. We characterized the pharmacogenetics of this interaction. METHODS: In A5338, women receiving efavirenz-based HIV therapy and rifampicin plus isoniazid for tuberculosis underwent pharmacokinetic evaluations over 12 weeks following a 150-mg intramuscular injection of depot MPA. Data were interpreted with nonlinear mixed-effects modelling. Associations between individual pharmacokinetic parameters and polymorphisms relevant to rifampicin, isoniazid, efavirenz, and MPA were assessed. RESULTS: Of 62 A5338 participants in four African countries, 44 were evaluable for pharmacokinetic associations, with 17 CYP2B6 normal, 21 intermediate, and 6 poor metabolizers, and 5 NAT2 rapid, 20 intermediate, and 19 slow acetylators. There were no associations between either CYP2B6 or NAT2 genotype and MPA Cmin at week 12, apparent clearance, Cmax, area under the concentration-time curve (AUC) or half-life, or unexplained interindividual variability in clearance, and uptake rate constant or mean transit time of the slow-release fraction (P > 0.05 for each). In exploratory analyses, none of 28 polymorphisms in 14 genes were consistently associated with MPA pharmacokinetic parameters, and none withstood correction for multiple testing. CONCLUSIONS: Study A5338 suggested that more frequent depot MPA dosing may be appropriate for women receiving rifampicin, isoniazid, and efavirenz. The present results suggest that knowledge of CYP2B6 metabolizer or NAT2 acetylator status does not inform individualized DMPA dosing in this setting.

Isoniazid Adherence Reduces Mortality and Incident Tuberculosis at 96 Weeks Among Adults Initiating Antiretroviral Therapy With Advanced Human Immunodeficiency Virus in Multiple High-Burden Settings.

Background: People with human immunodeficiency virus (HIV) and advanced immunosuppression initiating antiretroviral therapy (ART) remain vulnerable to tuberculosis (TB) and early mortality. To improve early survival, isoniazid preventive therapy (IPT) or empiric TB treatment have been evaluated; however, their benefit on longer-term outcomes warrants investigation. Methods: We present a 96-week preplanned secondary analysis among 850 ART-naive outpatients (≥13 years) enrolled in a multicountry, randomized trial of efavirenz-containing ART plus either 6-month IPT (n = 426) or empiric 4-drug TB treatment (n = 424). Inclusion criteria were CD4 count <50 cells/mm3 and no confirmed or probable TB. Death and incident TB were compared by strategy arm using the Kaplan-Meier method. The impact of self-reported adherence (calculated as the proportion of 100% adherence) was assessed using Cox-proportional hazards models. Results: By 96 weeks, 85 deaths and 63 TB events occurred. Kaplan-Meier estimated mortality (10.1% vs 10.5%; P = .86) and time-to-death (P = .77) did not differ by arm. Empiric had higher TB risk (6.1% vs 2.7%; risk difference, -3.4% [95% confidence interval, -6.2% to -0.6%]; P = .02) and shorter time to TB (P = .02) than IPT. Tuberculosis medication adherence lowered the hazards of death by ≥23% (P < .0001) in empiric and ≥20% (P < .035) in IPT and incident TB by ≥17% (P ≤ .0324) only in IPT. Conclusions: Empiric TB treatment offered no longer-term advantage over IPT in our population with advanced immunosuppression initiating ART. High IPT adherence significantly lowered death and TB incidence through 96 weeks, emphasizing the benefit of ART plus IPT initiation and completion, in persons with advanced HIV living in high TB-burden, resource-limited settings.

Adult Hematology and Clinical Chemistry Laboratory Reference Ranges in a Zimbabwean Population.

BACKGROUND: Laboratory reference ranges used for clinical care and clinical trials in various laboratories in Zimbabwe were derived from textbooks and research studies conducted more than ten years ago. Periodic verification of these ranges is essential to track changes over time. The purpose of this study was to establish hematology and chemistry laboratory reference ranges using more rigorous methods. METHODS: A community-based cross-sectional study was carried out in Harare, Chitungwiza, and Mutoko. A multistage sampling technique was used. Samples were transported from the field for analysis at the ISO15189 certified University of Zimbabwe-University of California San Francisco Central Research Laboratory. Hematology and clinical chemistry reference ranges lower and upper reference limits were estimated at the 2.5th and 97.5th percentiles respectively. RESULTS: A total of 769 adults (54% males) aged 18 to 55 years were included in the analysis. Median age was 28 [IQR: 23-35] years. Males had significantly higher red cell counts, hemoglobin, hematocrit, and mean corpuscular hemoglobin compared to females. Females had higher white cell counts, platelets, absolute neutrophil counts, and absolute lymphocyte counts compared to males. There were no gender differences in eosinophils, monocytes, and absolute basophil count. Males had significantly higher levels of urea, sodium, potassium, calcium, creatinine, amylase, total protein, albumin and liver enzymes levels compared to females. Females had higher cholesterol and lipase compared with males. There are notable differences in the white cell counts, neutrophils, cholesterol, and creatinine kinase when compared with the currently used reference ranges. CONCLUSION: Data from this study provides new country specific reference ranges which should be immediately adopted for routine clinical care and accurate monitoring of adverse events in research studies.