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Background. Neonatal enterovirus sepsis has high mortality. Antiviral therapy is not available. Methods. Neonates with suspected enterovirus sepsis (hepatitis, coagulopathy, and/or myocarditis) with onset at ≤15 days of life were randomized 2:1 to receive oral pleconaril or placebo for 7 days. Serial virologic (oropharynx, rectum, urine, serum), clinical, pharmacokinetic, and safety evaluations were performed. Results. Sixty-one subjects were enrolled (43 treatment, 18 placebo), of whom 43 were confirmed enterovirus infected (31 treatment, 12 placebo). There was no difference in day 5 oropharyngeal culture positivity (primary endpoint; 0% in both groups). However, enterovirus-infected subjects in the treatment group became culture negative from all anatomic sites combined faster than placebo group subjects (median 4.0 versus 7.0 days, P = .08), and fewer subjects in the treatment group remained polymerase chain reaction (PCR)-positive from the oropharynx when last sampled (23% versus 58%, P = .02; median, 14.0 days). By intent to treat, 10/43 (23%) subjects in the treatment group and 8/18 (44%) in the placebo group died (P = .02 for 2-month survival difference); among enterovirus-confirmed subjects, 7/31 (23%) in the treatment group died versus 5/12 (42%) in the placebo group (P = .26). All pleconaril recipients attained concentrations greater than the IC90 after the first study day, but 38% were less than the IC90 during the first day of treatment. One subject in the treatment group and three in the placebo group had treatment-related adverse events. Conclusions. Shorter times to culture and PCR negativity and greater survival among pleconaril recipients support potential efficacy and warrant further evaluation. [ABSTRACT FROM AUTHOR]

Background. IMPAACT P1066 is a Phase I/II open-label multicenter trial to evaluate safety, tolerability, pharmacokinetics (PK), and efficacy of multiple raltegravir (RAL) formulations in human immunodeficiency virus (HIV)-infected youth. Methods. Dose selection of the oral suspension formulation for each cohort (IV: 6 months to <2 years and V: 4 weeks to <6 months) was based on review of short-term safety (4 weeks) and intensive PK evaluation. Safety data through Weeks 24 and 48 and Grade ≥3 or serious adverse events (AEs) were assessed. The primary virologic endpoint was achieving HIV RNA <400 copies/mL or ≥1 log10 reduction from baseline at Week 24 (Success). For Cohort IV, optimized background therapy (OBT) could have been initiated with RAL either at study entry or after intensive PK sampling was completed at Day 5-12. An OBT was started when RAL was initiated for Cohort V subjects because they were not permitted to have received direct antiretroviral therapy before enrollment. Results. Total accrual was 27 subjects in these 2 cohorts, including 1 subject who was enrolled but never started study drug (excluded from the analyses). The targeted PK parameters (area under the curve [AUC]0-12hr and C12hr) were achieved for each cohort allowing for dose selection. Through Week 48, there were 10 subjects with Grade 3+ AEs. Two were judged related to study drug. There was 1 discontinuation due to an AE of skin rash, 1 event of immune reconstitution syndrome, and no drug-related deaths. At Week 48, for Cohorts IV and V, 87.5% of subjects achieved virologic success and 45.5%had HIV RNA <50 copies/mL. At Week 48, gains in CD4 cells of 527.6 cells/mm3 and 7.3% were observed. Conclusions. A total of 6 mg/kg per dose twice daily of RAL for oral suspensionwas well tolerated and showed favorable virologic and immunologic responses. [ABSTRACT FROM AUTHOR]

Objectives Efavirenz is widely prescribed for HIV-1 infection, and CYP2B6 polymorphisms 516G→T and 983T→C define efavirenz slow metabolizer genotypes. To identify genetic predictors of higher plasma efavirenz concentrations beyond these two common functional alleles, we characterized associations with mid-dosing interval efavirenz concentrations in 84 HIV-infected adults, all carrying two copies of these major loss-of-function CYP2B6 alleles. Methods Study participants had been randomized to efavirenz-containing regimens in prospective clinical trials and had available plasma efavirenz assay data. Analyses focused on secondary metabolism pathway polymorphisms CYP2A6 -48T→G (rs28399433), UGT2B7 735A→G (rs28365062) and UGT2B7 802T→C (rs7439366). Exploratory analyses also considered 196 polymorphisms and 8 copy number variants in 41 drug metabolism/transport genes. Mid-dosing interval efavirenz concentrations at steady-state were obtained ≥8 h but <19 h post-dose. Linear regression was used to test for associations between polymorphisms and log-transformed efavirenz concentrations. Results Increased efavirenz concentrations were associated with CYP2A6 -48T→G in all subjects (P = 3.8 × 10−4) and in Black subjects (P = 0.027) and White subjects (P = 0.0011) analysed separately; and with UGT2B7 735 G/G homozygosity in all subjects (P = 0.006) and in Black subjects (P = 0.046) and White subjects (P = 0.062) analysed separately. In a multivariable model, CYP2A6 -48T→G and UGT2B7 735 G/G homozygosity remained significant (P < 0.05 for each). No additional polymorphisms or copy number variants were significantly associated with efavirenz concentrations. Conclusions Among individuals with a CYP2B6 slow metabolizer genotype, CYP2A6 and possibly UGT2B7 polymorphisms contribute to even higher efavirenz concentrations. [ABSTRACT FROM PUBLISHER]

Background. Our goals were to describe azithromycin (AZI) pharmacokinetics in maternal plasma (MP), fetal plasma (FP), and amniotic fluid (AF) following intra-amniotic infection (IAI) with Ureaplasma in pregnant rhesus monkeys and to explore concentration-response relationships.Methods. Following intra-amniotic inoculation of Ureaplasma parvum, rhesus monkeys received AZI (12.5 mg/kg every 12 hours intravenously for 10 days; n = 10). Intensive pharmacokinetic sampling of MP, FP, and AF was scheduled following the first (ie, single) dose and the last (ie, multiple) dose. Noncompartmental and pharmacokinetic modeling methods were used.Results. The AF area under the concentration-time curve at 12 hours was 0.22 µg×h/mL following a single dose and 6.3 µg×h/mL at day 10. MP and AF accumulation indices were 8.4 and 19, respectively. AZI AF half-life following the single dose and multiple dose were 156 and 129 hours, respectively. The median MP:FP ratio in concomitantly drawn samples was 3.2 (range, 1.3–9.6; n = 9). Eradication of U. parvum occurred at 6.6 days, with a 95% effective concentration (EC95) of 39 ng/mL for the maximum AZI AF concentration.Conclusions. Our study demonstrates that a maternal multiple-dose AZI regimen is effective in eradicating U. parvum IAI by virtue of intra-amniotic accumulation and suggests that antenatal therapy has the potential to mitigate complications associated with U. parvum infection in pregnancy, such as preterm labor and fetal sequelae. [ABSTRACT FROM PUBLISHER]

Under the Emergency Use Authorization issued in April 2009, oseltamivir can be used to treat 2009 influenza A (HIN1) virus infection in children aged <1 year. No data exist on the dosing of oseltamivir in premature babies. A hospital health care worker inadvertently exposed 32 neo-natal intensive care unit babies to 2009 influenza A (H1N1); a protocol was expeditiously implemented to collect samples for pharmacokinetics and dosage evaluation. Results suggest 1.0 mg/kg/dose twice daily in premature babies produces oseltamivir carboxylate exposures similar to that in older children receiving 3.0 mg/kg/dose twice daily. These results provide initial guidance on dosing oseltamivir in this vulnerable population. [ABSTRACT FROM AUTHOR]

The objective of this study was to serially quantitate the concentration of nevirapine in breast milk after discontinuation of treatment. Samples were collected from both breasts of a human immunodeficiency virus—infected patient for 3 weeks. Nevirapine was quantifiable for up to 17 days after discontinuation of therapy; total nevirapine concentrations remained above the 90% inhibitory concentration for 6 days, and no differences were observed between breasts. [ABSTRACT FROM AUTHOR]

Context Three-drug antiretroviral regimens are standard of care for initial treatment of human immunodeficiency virus 1 (HIV-1) infection, but a 4-drug regimen could improve antiretroviral activity and be more effective than a 3-drug regimen. Objective To compare the safety/efficacy of 3-drug vs 4-drug regimens for initial treatment of HIV-1 infection. Design The AIDS Clinical Trials Group (ACTG) A5095 study, a randomized, double- blind, placebo-controlled study with enrollment and follow-up conducted from March 22,2001, to March 1,2005, and enrolling treatment-naive, HIV-1-infected patients with HIV-1 RNA levels of 400 copies/mL or greater from US clinical trials units of the ACTG. Interventions Zidovudine/lamivudine plus efavirenz (3-drug regimen) vs zidovudine/lamivudine/abacavir plus efavirenz (4-drug regimen). Main Outcome Measures Time to virologic failure (defined as time to first of 2 successive HIV-1 RNA levels ≥200 copies/mL at or after week 16), CD4 cell count changes, and grade 3 or 4 adverse events. HIV-1 RNA data were intent-to-treat, regardless of treatment changes. Results Seven hundred sixty-five patients with a baseline mean HIV-1 RNA level of 4.86 log10 (72 444) copies/mL and CD4 cell count of 240 cells/mm3 were randomized. After a median 3-year follow-up, 99 (26%) of 382 and 94 (25%) of 383 patients receiving the 3-drug and 4-drug regimens, respectively, reached protocol-defined virologic failure; time to virologic failure was not significantly different (hazard ratio, 0.95; 97.5% confidence interval, 0.69-1.33; P= .73). In planned subgroup analyses, increased risk for virologic failure was seen in non-Hispanic black patients (adjusted hazard ratio, 1.66; 95% confidence interval, 1.18-2.34; P=.003). At 3 years, the HIV-1 RNA level was less than 200 copies/mL in 152 (90%) of 169 and 143 (92%) of 156 patients receiving the 3-drug and 4-drug regimens, respectively (P=.59), and less than 50 copies/mL in 144 (85%) of 169 and 137 (88%) of 156 patients (P=.39). CD4 cell count increases and grade 3 or 4 adverse events were not significantly different. Conclusions In treatment-naive patients, there were no significant differences between the 3-drug and 4-drug antiretroviral regimens; overall, at least approximately 80% of patients had HIV-1 RNA levels less than 50 copies/mL through 3 years. These results support current guidelines recommending 2 nucleosides plus efavirenz for initial treatment of HIV-1 infection; adding abacavir as a fourth drug provided no additional benefit. [ABSTRACT FROM AUTHOR]

Compares the pharmacokinetics, safety and tolerability of indinavir at 800/200 mg and 400/400 mg administered twice daily in HIV-infected subjects failing their first PI-based regimen. Details of the phase I/II randomized, open-label, 24-week study conducted; Formal 12-hour pharmacokinetic evaluations performed; Clinical symptoms and laboratory assessments.

Combination antiretroviral therapy with two or more protease inhibitors has become the standard of care in the treatment of HIV infection. Dual protein inhibitor (PI) regimens, such as lopinavir/ritonavir, are commonly used as initial PI therapy. As viral resistance increases and the development of mechanistically novel protease inhibitors decreases, clinicians turn to ritonavir-enhanced dual PI therpay to treat salvage patients. Potency of these combination regimens is increased while pill burden, food restrictions and often, side effects are decreased. These clincial advantages result from the enhancement of their pharmacological properties, including alterations in the absorption and metabolism process. Alterations in the absorption and metabolism of protease inhibitors when co-administered with a cytochrome P450 (CYP) enzyme inhibitor, such as low dose ritonavir, are reflected by impressive changes in pharmacokinetic parameters. For example, the addition of ritonavir 100 or 200mg to saquinavir 1200–1800mg has been shown to increase saquinavir area under the concentration-time curve (AUC) by approximately 300–800% compared with saquinavir alone. The ability of ritonavir to increase plasma trough concentrations (Cmin) of concomitantly administered PIs is perhaps the greatest clinical benefit of dual or ritonavir-enhanced dual PI therapy since inadequate concentrations of antiretrovirals may support long term antiretroviral resistance. For example, lopinavir 400mg alone in healthy volunteers produced plasma concentrations that briefly exceeded the concentration required to inhibit 50% of viral replication (IC50). Yet, when low doses of ritonavir were added, Cmin values were 50-to 100-fold greater than the concentration required to produce 50% of the maximum effect for wild-type HIV (EC50). The following manuscript will discuss the rationale for combining protease inhibitors and will review pertinent pharmacokinetic and clinical data on these combination regimens. [ABSTRACT FROM AUTHOR]

The use of therapeutic drug monitoring (TDM) in the treatment of HIV-infection is gaining momentum in resource-rich countries. However, data justifying its use is still in short supply. In this manuscript we review the necessary components of TDM before it should be implemented in widespread clinical use. In addition, we provide specific examples of clinical situations where TDM is likely to useful. The overall conclusion of this review is that TDM is a promising therapeutic modality for improving antiretroviral efficacy and reducing toxicity. However, more prospective clinical trials are necessary in order to validate the therapeutic concentrations of antiretroviral drugs suggested by various investigators. In addition, both the clinical utility and cost effectiveness of TDM will need to be demonstrated by well-designed and adequately powered clinical trials in both antiretroviral naı¨ve and experienced subjects. At this point in time we consider TDM in the treatment of HIV-infection as experimental with significant promise for the future. [Copyright &y& Elsevier]

Interest in monitoring antiretroviral drug concentrations in human immunodeficiency virus-infected patients has gained considerable momentum in recent years. We present a potential method for integrating pharmacokinetic and phenotypic information that will assist clinicians in choosing optimal treatment regimens for their patients and that will provide an approach for the interpretation of antiretroviral plasma drug concentrations. [ABSTRACT FROM AUTHOR]

The AIDS Clinical Trials Group Study 850 (ACTG 850) evaluated the penetration of zidovudine (ZDV), lamivudine (3TC), and amprenavir (APV), given alone and in combination with the 2 nucleoside analogues, into the male genital tract, because these factors may affect human immunodeficiency virus (HIV) type 1 suppression and transmission. Nineteen men receiving APV monotherapy and 12 men receiving triple therapy donated blood plasma (BP) and seminal plasma (SP) during therapy. Paired SP and BP were used to calculate compartmental concentration ratios. APV SP concentrations were consistently lower than BP concentrations, ZDV SP concentrations approximated BP concentrations early but became greater later in the dosing interval, and 3TC SP concentrations were substantially greater than BP concentrations throughout. Observed SP concentrations plotted with population BP concentration-time curves confirmed these findings, suggesting that passive diffusion (APV), slowed elimination (ZDV), and either active accumulation and/or inhibition of elimination (3TC) are responsible for SP concentrations of these agents. The antiretroviral effect of APV monotherapy was related to APV concentrations. [ABSTRACT FROM AUTHOR]

Focuses on several aspects on the use of protease inhibitors (PI) for the treatment of HIV infection. Factors influencing the pharmacokinetic and pharmacodynamic profiles of PI; Differences between in vitro and in vivo approaches; Discussion on issues concerning therapeutic drug monitoring.

Looks into the clinical implications of the pharmacodynamics of HIV type one protease inhibitors. Correlation between the changes in plasma HIV ribonucleic acid (RNA) levels with concentrations of saquinavir; Correlation between the number of in vivo drug-resistant mutations and ritonavir concentrations; Absence of a correlation between indinavir concentrations and changes in plasma HIV RNA levels.

A response from authors D. W. Kimberlin, I. Aban and E. P. Acosta of the article "Valganciclovir for Congenital Cytomegalovirus" in the March 5, 2015 issue is presented.

Summary: Purpose: To evaluate the impact of enzyme-inducing antiepileptic drugs (EI-AEDs) on serum antiretroviral (ARV) levels in patients with HIV. Methods: Data from the U.S. Military HIV Natural History Study were screened to identify participants taking ARVs with EI-AEDs and controls taking ARVs with non enzyme-inducing AEDs (NEI-AEDs). The proportion of serum ARV levels below the recommended minimum concentrations (C min) was compared between these groups. Results: ARV levels were available for 10 individuals exposed to 16 intervals on combined ARVs/EI-AEDs (phenytoin and carbamazepine) and for 25 controls exposed to 30 overlap intervals on combined ARVs/NEI-AEDs. The percentage of overlap intervals with ≥1 ARV levels below C min was higher in the EI-AED group than in controls (37.5% vs. 23.3%; p =0.124). After excluding intervals associated with serum levels of EI-AEDs below the reference range (n =6), the proportion of intervals with ≥1 ARV level below C min was significantly greater among EI-AED recipients (60%) compared to controls (23.3%; p =0.008). Conclusions: ARV levels below C min were more common in participants receiving EI-AEDs, the difference being statistically significant for intervals associated with EI-AED levels within the reference range. These data suggest that, in agreement with current guidelines, EI-AEDs should be avoided in patients receiving ARV therapy. [Copyright &y& Elsevier]

The article presents a study on the hepatotoxicity and gastrointestinal intolerance of healthy volunteers taking rifampin add twice-daily atazanavir and ritonavir. The study primarily evaluates the pharmoacokinetic interactions and safety of atazanavir, ritonavir and rifampin among HIV-seronegative volunteers. Results are included, concluding that the co-administration of rifampin with HIV protease inhibitors may not be a viable treatment option for protease inhibitor irritation.

Background: Regimens containing three nucleoside reverse-transcriptase inhibitors offer an alternative to regimens containing nonnucleoside reverse-transcriptase inhibitors or protease inhibitors for the initial treatment of human immunodeficiency virus type 1 (HIV-1) infection, but data from direct comparisons are limited. Methods: This randomized, double-blind study involved three antiretroviral regimens for the initial treatment of subjects infected with HIV-1: zidovudine–lamivudine–abacavir, zidovudine–lamivudine plus efavirenz, and zidovudine–lamivudine–abacavir plus efavirenz. REsults We enrolled a total of 1147 subjects with a mean baseline HIV-1 RNA level of 4.85 log10 (71,434) copies per milliliter and a mean CD4 cell count of 238 per cubic millimeter were enrolled. A scheduled review by the data and safety monitoring board with the use of prespecified stopping boundaries led to a recommendation to stop the triple-nucleoside group and to present the results in the triple-nucleoside group in comparison with pooled data from the efavirenz groups. After a median follow-up of 32 weeks, 82 of 382 subjects in the triple-nucleoside group (21 percent) and 85 of 765 of those in the combined efavirenz groups (11 percent) had virologic failure; the time to virologic failure was significantly shorter in the triple-nucleoside group (P<0.001). This difference was observed regardless of the pretreatment HIV-1 RNA stratum (at least 100,000 copies per milliliter or below this level; P≤0.001 for both comparisons). Changes in the CD4 cell count and the incidence of grade 3 or grade 4 adverse events did not differ significantly between the groups. Conclusions: In this trial of the initial treatment of HIV-1 infection, the triple-nucleoside combination of abacavir, zidovudine, and lamivudine was virologically inferior to a regimen containing efavirenz and two or three nucleosides. N Engl J Med 2004;350:1850-61. [ABSTRACT FROM AUTHOR]