Pharmacogenetic interactions between antiretroviral drugs and vaginally administered hormonal contraceptives.

OBJECTIVE: In AIDS Clinical Trials Group study A5316, efavirenz lowered plasma concentrations of etonogestrel and ethinyl estradiol, given as a vaginal ring, while atazanavir/ritonavir increased etonogestrel and lowered ethinyl estradiol concentrations. We characterized the pharmacogenetics of these interactions. METHODS: In A5316, women with HIV enrolled into control (no antiretrovirals), efavirenz [600 mg daily with nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs)], and atazanavir/ritonavir (300/100 mg daily with NRTIs) groups. On day 0, a vaginal ring was inserted, releasing etonogestrel/ethinyl estradiol 120/15 µg/day. Intensive plasma sampling for antiretrovirals was obtained on days 0 and 21, and single samples for etonogestrel and ethinyl estradiol on days 7, 14, and 21. Seventeen genetic polymorphisms were analyzed. RESULTS: The 72 participants in this analysis included 25, 24 and 23 in the control, efavirenz, and atazanavir/ritonavir groups, respectively. At day 21 in the efavirenz group, CYP2B6 genotype was associated with increased plasma efavirenz exposure (P = 3.2 × 10), decreased plasma concentrations of etonogestrel (P = 1.7 × 10), and decreased ethinyl estradiol (P = 6.7 × 10). Compared to controls, efavirenz reduced median etonogestrel concentrations by at least 93% in CYP2B6 slow metabolizers versus approximately 75% in normal and intermediate metabolizers. Efavirenz reduced median ethinyl estradiol concentrations by 75% in CYP2B6 slow metabolizers versus approximately 41% in normal and intermediate metabolizers. CONCLUSION: CYP2B6 slow metabolizer genotype worsens the pharmacokinetic interaction of efavirenz with hormonal contraceptives administered by vaginal ring. Efavirenz dose reduction in CYP2B6 slow metabolizers may reduce, but will likely not eliminate, this interaction.

Raltegravir pharmacokinetics before and during treatment with ombitasvir, paritaprevir/ritonavir plus dasabuvir in adults with human immunodeficiency virus-1 and hepatitis C virus coinfection: AIDS Clinical Trials Group sub-study A5334s.

AIMS: AIDS Clinical Trials Group study A5334s evaluated the pharmacokinetics of raltegravir before and during combined administration of ombitasvir, paritaprevir/ritonavir, plus dasabuvir (OBV/PTV/r + DSV) and weight-based ribavirin in human immunodeficiency virus (HIV) and hepatitis C virus (HCV) coinfected adults. The pharmacokinetics of OBV/PTV/r + DSV during raltegravir coadministration were also characterized. METHODS: Adults living with HIV/HCV coinfection receiving steady-state raltegravir (400 mg twice daily) with 2 nucleos(t)ide analogues were enrolled. Pharmacokinetics of raltegravir were assessed prior to HCV therapy, and 4 weeks later following initiation of OBV/PTV/r (25/150/100 mg) once daily + DSV (250 mg) twice daily. Geometric mean ratios (GMRs) and 90% confidence intervals (CIs) were used to compare the following: raltegravir pharmacokinetics with HCV therapy (week 4) vs before HCV therapy (week 0); OBV/PTV/r and DSV pharmacokinetics vs historical healthy controls; raltegravir pharmacokinetics at week 0 vs historical control adults living with HIV. RESULTS: Eight of 11 participants had decreased raltegravir exposures after initiation of HCV therapy. The GMRs (90% CI) for maximum concentration and area under the concentration-time curve of raltegravir with vs without HCV therapy were 0.68 (0.38-1.19) and 0.82 (0.58-1.17), respectively. Comparing OBV/PTV/r pharmacokinetics in healthy controls, A5334s study participants demonstrated generally lower maximum concentration and area under the concentration-time curve values by 41-82% and 4-73%, respectively. Raltegravir exposures tended to be higher in A5334s study participants compared to adults living with HIV. CONCLUSIONS: The majority of participants' plasma raltegravir exposures were lower after initiation of HCV therapy in coinfected adults; however, confidence intervals were wide.

Assessing Prolongation of the Corrected QT Interval with Bedaquiline and Delamanid Coadministration to Predict the Cardiac Safety of Simplified Dosing Regimens.

Delamanid and bedaquiline are two drugs approved to treat drug-resistant tuberculosis, and each have been associated with corrected QT interval (QTc) prolongation. We aimed to investigate the relationships between the drugs' plasma concentrations and the prolongation of observed QT interval corrected using Fridericia's formula (QTcF) and to evaluate their combined effects on QTcF, using a model-based population approach. Furthermore, we predicted the safety profiles of once daily regimens. Data were obtained from a trial where participants were randomized 1:1:1 to receive delamanid, bedaquiline, or delamanid + bedaquiline. The effect on QTcF of delamanid and/or its metabolite (DM-6705) and the pharmacodynamic interactions under coadministration were explored based on a published model between bedaquiline's metabolite (M2) and QTcF. The metabolites of each drug were found to be responsible for the drug-related QTcF prolongation. The final drug-effect model included a competitive interaction between M2 and DM-6705 acting on the same cardiac receptor and thereby reducing each other's apparent potency, by 28% (95% confidence interval (CI), 22-40%) for M2 and 33% (95% CI, 24-54%) for DM-6705. The generated combined effect was not greater but close to "additivity" in the analyzed concentration range. Predictions with the final model suggested a similar QT prolonging potential with simplified, once-daily dosing regimens compared with the approved regimens, with a maximum median change from baseline QTcF increase of 20 milliseconds in both regimens. The concentrations-QTcF relationship of the combination of bedaquiline and delamanid was best described by a competitive binding model involving the two main metabolites. Model predictions demonstrated that QTcF prolongation with simplified once daily regimens would be comparable to currently used dosing regimens.

QT effects of bedaquiline, delamanid, or both in patients with rifampicin-resistant tuberculosis: a phase 2, open-label, randomised, controlled trial.

BACKGROUND: Bedaquiline and delamanid are the first drugs of new classes registered for tuberculosis treatment in 40 years. Each can prolong the QTc interval, with maximum effects occurring weeks after drug initiation. The cardiac safety and microbiological activity of these drugs when co-administered are not well-established. Our aim was to characterise the effects of bedaquiline, delamanid, or both on the QTc interval, longitudinally over 6 months of multidrug treatment, among patients with multidrug-resistant or rifampicin-resistant tuberculosis taking multidrug background therapy. METHODS: ACTG A5343 is a phase 2, open-label, randomised, controlled trial in which adults with multidrug-resistant or rifampicin-resistant tuberculosis receiving multidrug background treatment were randomly assigned 1:1:1 by centrally, computer-generated randomisation, by means of permuted blocks to receive bedaquiline, delamanid, or both for 24 weeks. Participants were enrolled at TASK in Cape Town and the South African Tuberculosis Vaccine Initiative in Worcester, both in South Africa, and Hospital Maria Auxiliadora in Peru. Individuals with QTc greater than 450 ms were excluded. HIV-positive participants received dolutegravir-based antiretroviral therapy. Clofazimine was disallowed, and levofloxacin replaced moxifloxacin. ECG in triplicate and sputum cultures were done fortnightly. The primary endpoint was mean QTcF change from baseline (averaged over weeks 8-24); cumulative culture conversation at week 8-24 was an exploratory endpoint. Analyses included all participants who initiated study tuberculosis treatment (modified intention-to-treat population). This trial is registered with ClinicalTrials.gov, NCT02583048 and is ongoing. FINDINGS: Between Aug 26, 2016 and July 13, 2018, of 174 screened, 84 participants (28 in each treatment group, and 31 in total with HIV) were enrolled. Two participants did not initiate study treatment (one in the delamanid group withdrew consent and one in the bedaquiline plus delamanid group) did not meet the eligibility criterion). Mean change in QTc from baseline was 12·3 ms (95% CI 7·8-16·7; bedaquiline), 8·6 ms (4·0-13·1; delamanid), and 20·7 ms (16·1-25·3) (bedaquiline plus delamanid). There were no grade 3 or 4 adverse QTc prolongation events and no deaths during study treatment. Cumulative culture conversion by week 8 was 21 (88%) of 24 (95% CI 71-97; bedaquiline), 20 (83%) of 24 (65-95; delamanid), and 19 (95%) of 20 (79-100; bedaquiline plus delamanid) and was 92% (77-99) for bedaquiline, 91% (76-99), for delamanid, and 95% (79-100) for bedaquiline plus delamanid at 24 weeks. INTERPRETATION: Combining bedaquiline and delamanid has a modest, no more than additive, effect on the QTc interval, and initial microbiology data are encouraging. This study provides supportive evidence for use of these agents together in patients with multidrug-resistant or rifampicin-resistant tuberculosis with normal baseline QTc values. FUNDING: Division of AIDS, National Institutes of Health.

Antiretroviral Activity of AMD11070 (An Orally Administered CXCR4 Entry Inhibitor): Results of NIH/NIAID AIDS Clinical Trials Group Protocol A5210.

AMD11070 binds to the chemokine receptor CXCR4, with anti-HIV-1 activity in vitro and in vivo. We conducted a phase IB/IIA proof-of-concept dose-escalating, open-label study to determine safety and antiviral activity of AMD11070 administered over 10 days to HIV-1-infected participants who harbored CXCR4-tropic virus. Primary endpoints were ≥1 log10 rlu (relative luminescence units) reduction in CXCR4-tropic virus during 10 days of AMD11070 treatment or in the 7 days following treatment discontinuation, rlu changes over 10 days of treatment, and safety. Plasma pharmacokinetic parameters, HIV-1 RNA, and safety labs were obtained over 90 days of study. The study was stopped early due to emerging AMD11070 animal toxicity data. Six HIV-infected participants with plasma HIV-1 RNA ≥5,000 copies/mL on no antiretroviral therapy for 14 days before entry were treated. AMD11070 was well-tolerated when administered at 200 mg orally every 12 h for 10 days. All enrolled participants had dual/mixed (D/M) viruses. Reductions of almost 1 log10 rlu or more in CXCR4 virus were seen in three of six participants after 10 days of treatment. No participants had ≥1 log10 decline in plasma HIV-1 RNA from baseline at day 10. No clear relationship between pharmacokinetic parameters and response to therapy (X4 log rlu reduction) was observed. AMD11070 demonstrated in vivo activity as measured by reductions in CXCR4 rlu signal. Despite the finding of discordant rlu and plasma HIV RNA responses in these participants with D/M viruses, exploration of other HIV-1 CXCR4 antagonist therapies is possible.

Antiretroviral therapy and vaginally administered contraceptive hormones: a three-arm, pharmacokinetic study.

BACKGROUND: Drug-drug interactions between orally administered antiretroviral therapy (ART) and hormones released from an intravaginal ring are not known. We hypothesised that ART containing either efavirenz or ritonavir-boosted atazanavir would alter plasma concentrations of vaginally administered etonogestrel and ethinylestradiol but that ART concentrations would be unchanged during use of an intravaginal ring. METHODS: We did a parallel, three-group, pharmacokinetic evaluation at HIV clinics in Asia (two sites), South America (five), sub-Saharan Africa (three), and the USA (11) between Dec 30, 2014, and Sept 12, 2016. We enrolled women with HIV who were either ART-naive (control group; n=25), receiving efavirenz-based ART (n=25), or receiving atazanavir-ritonavir-based ART (n=24). Women receiving ART were required to be on the same regimen for at least 30 days, with 400 copies or less per mL of plasma HIV-1 RNA; women not receiving ART had CD4 counts of 350 cells per µL or less. We excluded participants who had a bilateral oophorectomy or conditions that were contraindicated in the intravaginal ring product labelling. An intravaginal ring releasing etonogestrel and ethinylestradiol was inserted at entry (day 0). Single plasma samples for hormone concentrations were collected on days 7, 14, and 21 after intravaginal ring insertion. The primary outcome was the plasma concentration of etonogestrel and ethinylestradiol on day 21. Etonogestrel and ethinylestradiol concentrations were compared between each ART group and the control group by geometric mean ratio (GMR) with 90% CIs and Wilcoxon rank-sum test. As secondary outcomes, efavirenz or ritonavir-boosted atazanavir concentrations were assessed by 8-h intensive pharmacokinetic sampling at entry before intravaginal ring insertion and before intravaginal ring removal on day 21. Antiretroviral areas under the concentration-time curve (AUC0-8 h) were compared before and after intravaginal ring insertion by GMR (90% CI) and Wilcoxon signed-rank test. This study is registered with ClinicalTrials.gov, number NCT01903031. FINDINGS: Between Dec 30, 2014, and Sept 12, 2016, we enrolled 84 participants in the study; ten participants were excluded from the primary hormone analysis. 74 participants met the primary endpoint: 25 in the control group, 25 in the efavirenz group, and 24 in the atazanavir group. On day 21 of intravaginal ring use, participants receiving efavirenz had 79% lower etonogestrel (GMR 0·21, 90% CI 0·16-0·28; p<0·0001) and 59% lower ethinylestradiol (0·41, 0·32-0·52; p<0·0001) concentrations compared with the control group. By contrast, participants receiving ritonavir-boosted atazanavir had 71% higher etonogestrel (1·71, 1·37-2·14; p<0·0001), yet 38% lower ethinylestradiol (0·62, 0·49-0·79; p=0·0037) compared with the control group. The AUC0-8 h of efavirenz or atazanavir did not differ between the groups. INTERPRETATION: Hormone exposure was significantly lower when an intravaginal ring contraceptive was combined with efavirenz-based ART. Further studies designed to examine pharmacodynamic endpoints, such as ovulation, when intravaginal ring hormones are combined with efavirenz are warranted. FUNDING: National Institutes of Health, through the AIDS Clinical Trials Group and the International Maternal Pediatric Adolescent AIDS Clinical Trials Network, National Institute of Allergy and Infectious Diseases, Eunice Kennedy Shriver National Institute of Child Health and Human Development, and the National Institute of Mental Health.

Effect of hydroxyurea and dideoxyinosine on intracellular 3'-deoxyadenosine-5'-triphosphate concentrations in HIV-infected patients.

Hydroxyurea (HU) significantly enhances the antiretroviral effects of the adenosine analog reverse transcriptase inhibitor dideoxyinosine (ddI). This is believed to be due to a reduction in intracellular de-oxyadenosine triphosphate (dATP) concentrations resulting from HU-mediated inhibition of ribonucleotide reductase (RnR). The effect of combined HU-ddI treatment on intracellular dATP pools in vivo has not been examined. We measured intracellular dATP concentrations in peripheral blood mononuclear cells (PBMCs) from 69 HIV-infected patients receiving 1000 or 1500 mg HU daily for 14 days, 200 mg ddI twice daily for 14 days, or a combination of the two drugs. Median intracellular dATP concentrations decreased from base-line to day 14 by 46% in the ddI + 1000 mg HU arm and by 62% in the ddI + 1500 mg HU arm. When compared to the HU monotherapy arms, these changes proved statistically significant (p = 0.018; stratified Wilcoxon rank-sum test). These findings support reduced intracellular dATP as the mechanism of ddI-HU synergistic activity, and indicate that changes in intracellular nucleotides contribute to HU activity and toxicity in patients. Since a significant reduction in dATP was measurable only when ddI was combined with HU, the antiretroviral activity of ddI may be more complex than previously assumed.

The pharmacokinetics and pharmacogenomics of efavirenz and lopinavir/ritonavir in HIV-infected persons requiring hemodialysis.

OBJECTIVE: To evaluate the pharmacokinetics and pharmacogenomics of efavirenz (EFV) and lopinavir/ritonavir (LPV/RTV) in HIV-infected persons requiring hemodialysis. DESIGN: Prospective, observational study of HIV-infected hemodialysis patients receiving one 600 mg tablet daily of EFV (N = 13) or three 133.3/33.3 mg capsules twice daily of LPV/RTV (N = 13). METHODS: Twenty-four-hour EFV and 12-h LPV/RTV pharmacokinetics were assessed. Geometric mean ratios were calculated using historical controls with normal renal function. The effects of several candidate gene polymorphisms were also explored. RESULTS: The geometric mean [95% confidence interval (CI); percentage of coefficient of variation (% CV)] Cmin, Cmax, and area under the curve (AUC) for the EFV group were 1.81 microg/ml (0.93, 3.53; 103%), 5.04 microg/ml (3.48, 7.29; 72%), and 71.5 microg h/ml (43.2, 118.3; 93%), respectively. These parameters were 2.76 microg/ml (1.86, 4.11; 53%), 8.45 microg/ml (6.41, 11.15; 52%), and 69.6 microg h/ml (55.6, 87.2; 37%) for LPV and 0.08 microg/ml (0.05, 0.14; 63%), 0.58 microg/ml (0.44, 0.76; 41%), and 3.74 microg h/ml (2.91, 4.80; 37%) for RTV. The AUC geometric mean ratios (90% CI) for EFV, LPV, and RTV were 132% (89, 197), 81% (67, 97), and 92% (76, 111), respectively. LPV Cmin was lower than expected in the hemodialysis group. Higher EFV concentrations were associated with the CYP2B6 516G>T polymorphism. CONCLUSION: The pharmacokinetics of EFV and LPV/RTV in hemodialysis suggests that no dosing adjustments are necessary in treatment-naive patients. As HIV-infected hemodialysis patients are disproportionately black, the increased frequency of the CYP2B6 516G>T polymorphism may lead to higher EFV levels. The potentially lower LPV trough levels in this population suggest that LPV/RTV should be used with caution in protease-inhibitor-experienced patients.