Assessment of drug interaction potential between the HCV direct-acting antiviral agents elbasvir/grazoprevir and the HIV integrase inhibitors raltegravir and dolutegravir.

BACKGROUND: Elbasvir/grazoprevir is a once-daily fixed-dose combination therapy for the treatment of chronic HCV infection, including HCV/HIV coinfection. OBJECTIVES: To evaluate the pharmacokinetic interaction of elbasvir and grazoprevir with raltegravir or dolutegravir. METHODS: Three open-label trials in healthy adult participants were conducted. In the raltegravir trials, participants received a single dose of raltegravir 400 mg, a single dose of elbasvir 50 mg or grazoprevir 200 mg, and raltegravir with either elbasvir or grazoprevir. In the dolutegravir trial, participants received a single dose of dolutegravir 50 mg alone or co-administered with once-daily elbasvir 50 mg and grazoprevir 200 mg. RESULTS: The raltegravir AUC0-∞ geometric mean ratio (GMR) (90% CI) was 1.02 (0.81-1.27) with elbasvir and 1.43 (0.89-2.30) with grazoprevir. Dolutegravir AUC0-∞ GMR (90% CI) was 1.16 (1.00-1.34) with elbasvir and grazoprevir. The elbasvir AUC0-∞ GMR (90% CI) was 0.81 (0.57-1.17) with raltegravir and 0.98 (0.93-1.04) with dolutegravir. The grazoprevir AUC0-24 GMR (90% CI) was 0.89 (0.72-1.09) with raltegravir and 0.81 (0.67-0.97) with dolutegravir. CONCLUSIONS: Elbasvir or grazoprevir co-administered with raltegravir or dolutegravir resulted in no clinically meaningful drug-drug interactions and was generally well tolerated. These results support the assertion that no dose adjustments for elbasvir, grazoprevir, raltegravir or dolutegravir are needed for co-administration in HCV/HIV-coinfected people.

Similar neurocognitive outcomes after 48 weeks in HIV-1-infected participants randomized to continue tenofovir/emtricitabine + atazanavir/ritonavir or simplify to abacavir/lamivudine + atazanavir.

Human immunodeficiency virus (HIV)-associated neurocognitive disorders can persist in many patients despite achieving viral suppression while on antiretroviral therapy (ART). Neurocognitive function over 48 weeks was evaluated using a Cogstate test battery assessing psychomotor function, attention, learning, and working memory in 293 HIV-1-infected, ART-experienced, and virologically suppressed adults. The ASSURE study randomized participants 1:2 to remain on tenofovir/emtricitabine (TDF/FTC) and ritonavir-boosted atazanavir (ATV/r) or simplify to abacavir/lamivudine + atazanavir (ABC/3TC + ATV). Neurocognitive z-scores were computed using demographically adjusted normative data and were classified as "impaired" (defined as either a z-score ≤ - 2 or having 2 or more standardized individual test z-scores ≤ - 1); while higher scores (equaling better performance) were classified as "normal". By z-scores, 54.7% of participants had impaired neurocognition at baseline and 50.2% at week 48. There were no significant differences (p < 0.05) in the baseline-adjusted performance between treatment groups for any individual test or by z-score. Specific demographic and medical risk factors were evaluated by univariate analysis for impact on neurocognitive performance. Factors with p < 0.10 were evaluated by backwards regression analysis to identify neurocognition-correlated factors after accounting for treatment, assessment, and baseline. Four risk factors at baseline for impaired neurocognition were initially identified: lower CD4 nadir lymphocyte counts, higher Framingham risk scores, and interleukin-6 levels, and a history of psychiatric disorder not otherwise specified, however none were found to moderate the effect of treatment on neurocognition. In this aviremic, treatment-experienced population, baseline-adjusted neurocognitive function remained stable and equivalent over 48 weeks with both TDF/FTC + ATV/r-treated and in the ART-simplified ABC/3TC + ATV treatment groups.

HLA-B*57:01 allele prevalence in HIV-infected North American subjects and the impact of allele testing on the incidence of abacavir-associated hypersensitivity reaction in HLA-B*57:01-negative subjects.

BACKGROUND: The presence of the HLA-B*57:01 allele in HIV-infected subjects is associated with a higher risk of abacavir-associated hypersensitivity reaction (ABC HSR). HLA-B*57:01 allele prevalence varies in different populations, but HLA-B*57:01 testing with immunological confirmation has had a negative predictive value for ABC HSR between 97 and 100%. METHODS: In the ASSURE study (EPZ113734), the HLA-B*57:01 prevalence in virologically suppressed, antiretroviral treatment-experienced, HIV-infected subjects from the United States, including Puerto Rico, was assessed. RESULTS: Three hundred eighty-five subjects were screened; 13 were HLA-B*57:01 positive and 372 were negative. Only HLA-B*57:01-negative, abacavir-naive subjects were eligible to enroll into the ASSURE trial. Eleven of the 13 subjects who possessed the HLA-B*57:01 allele were white, the other 2 were African-American. There was no geographic clustering of HLA-B*57:01-positive subjects, and the incidence correlated roughly with those states with the greatest numbers of subjects screened. Similarly, there was no statistically significant correlation between subjects who possessed or lacked the allele and age, gender, ethnicity or CD4+ T-cell numbers. The incidence of ABC HSR following abacavir initiation was also evaluated. Only 1 of 199 HLA-B*57:01-negative subjects (an African-American male) randomized to receive abacavir-containing treatment developed symptoms consistent with suspected ABC HSR; ABC HSR was not immunologically confirmed. CONCLUSIONS: These findings confirm the utility of HLA-B*57:01 allele testing to reduce the frequency of ABC HSR. The prevalence of HLA-B*57:01 positivity was higher in white than in African-American subjects. In HLA-B*57:01-negative subjects, suspected ABC HSR is very rare, but should lead to discontinuation of abacavir when ABC HSR cannot be definitively excluded from the differential diagnosis. TRIAL REGISTRATION: The ASSURE (EPZ113734) study was registered on ClinicalTrials.gov registration on April 8th 2010 and the registration number is NCT01102972.

No clinically significant pharmacokinetic interactions between dolutegravir and daclatasvir in healthy adult subjects.

BACKGROUND: Daclatasvir (DCV) is an NS5A replication complex inhibitor recently approved for chronic hepatitis C virus treatment. METHODS: To assess drug interactions between the HIV integrase strand transfer inhibitor dolutegravir (DTG) and DCV, subjects were randomized into 1 of 2 sequences in an open-label, 3-period, crossover study. Subjects received either DTG 50 mg once daily or DCV 60 mg once daily for 5 days in periods 1 and 2 and DTG 50 mg plus DCV 60 mg once daily for 5 days in period 3, with no washout between periods 2 and 3. Between periods 1 and 2, there was a washout period of at least 7 days. RESULTS: The geometric least-squares mean ratios (90 % confidence intervals) of DCV area under the concentration-time curve over a dosing interval (AUC0-τ), maximum observed concentration (Cmax), and concentration at the end of the dosing interval (Cτ) were 0.978 (0.831-1.15), 1.03 (0.843-1.25), and 1.06 (0.876-1.29), respectively, when DCV was administered with DTG compared with DCV alone. Compared with DTG alone, coadministration of DTG with DCV increased DTG AUC0-τ, Cmax, and Cτ by approximately 33, 29, and 45 %, respectively. CONCLUSIONS: DCV plasma exposure was not meaningfully affected by DTG. Coadministration of DTG with DCV resulted in slight increases in DTG AUC0-τ, Cmax, and Cτ. Accumulated safety and tolerability data in humans receiving DTG to date suggests this effect is not considered clinically significant. DTG and DCV can be coadministered without dose adjustment. TRIAL REGISTRATION: Registered on March 6, 2014 with ClinicalTrials.gov; registration number: NCT02082808 and as Study ID: 201102 on the ViiV Clinical Study Registry.

Study APV20002: Safety and Efficacy Results Through Week 684 for Pediatric Participants Living with HIV-1 Treated with Ritonavir-Boosted Fosamprenavir Oral Solution-Based Antiretroviral Therapy.

APV20002 was a multicenter, international, open-label study that began in 2003 investigating the pharmacokinetics, efficacy, and safety of ritonavir-boosted fosamprenavir (FPV/r) oral solution (OS) in combination with nucleoside reverse transcriptase inhibitor-based antiretroviral therapy (ART) in participants living with HIV-1 aged 4 weeks to <2 years with a primary endpoint at Week 48 (48W). Participants in APV20002 could continue in the study post-48W until FPV OS was locally available in their countries. Children were required to discontinue after reaching >39 kg or if FPV OS had no clinical benefit. Fifty-nine participants were enrolled; 5/59 received a single FPV OS visit for pharmacokinetic determinations. Most (38/54; 70%) were antiretroviral experienced; 39/59 participants had >48 weeks on treatment, 4/39 of whom discontinued after 48 weeks due to an adverse event (AE). At 48W, 88% of participants had HIV-1 RNA <400 copies/mL by Observed analysis; the proportion with HIV-1 RNA <400 copies/mL remained high (84%-100%) through Week 684. The median CD4+ cell count was 1,235 cells/mm3 [n = 51] at baseline, 1,690 cells/mm3 (n = 41) at Week 48, and 1,280 cells/mm3 (n = 21) at Week 180. From baseline to Week 684, 54/59 (92%) participants had ≥1 treatment-emergent AE regardless of causality; 42/59 (71%) had a treatment-emergent grade 2-4 AE, predominantly maximum toxicity: grade 2; 21/59 (36%) and 21/59 (36%) had severe or grade 3/4 AEs. From baseline to Week 684, 14/54 (26%) participants met virologic failure (VF) criteria, 9/14 before 48W. HIV from 1/9 VFs through 48W developed treatment-emergent reduced susceptibility to FPV and 1/9 to lamivudine/emtricitabine. Post-48W, 4/5 participants with VF had phenotype results; all were still susceptible to all study drugs at VF. In conclusion, FPV OS-based ART was efficacious and generally well tolerated in this long-running pediatric study through 684 weeks of treatment, with a safety profile consistent with experience in adults and older children.

ARIES 144 week results: durable virologic suppression in HIV-infected patients simplified to unboosted atazanavir/abacavir/lamivudine.

BACKGROUND: The open-label study ARIES (ClinicalTrials.gov NCT00440947) utilized a ritonavir (/r)-boosted protease inhibitor treatment simplification strategy. Antiretroviral-naïve subjects received abacavir/lamivudine (ABC/3TC) + atazanavir/ ritonavir (ATV/r) from baseline through randomization at week 36, then maintained or discontinued ritonavir for an additional 108 weeks. Non-inferiority of the unboosted regimen was demonstrated at week 84. In this optional extension phase, virologic suppression and adverse events were assessed through week 144. METHODS: Patients were randomized at week 36 if they had confirmed HIV RNA <50 copies/mL by week 30 and no previous virologic failure (VF; defined as failure to achieve HIV RNA <400 copies/mL or confirmed rebound after achieving HIV RNA ≥400 copies/mL). Three hundred sixty-nine subjects who completed 84 weeks in ARIES participated in the extension phase and maintained their randomized regimen for an additional 60 weeks post randomization. RESULTS: At week 144, 146/189 (77%) versus 132/180 (73%) subjects in the unboosted ATV and ATV/r groups, respectively, maintained HIV RNA <50 copies/mL. Post randomization (weeks 36-144), treatment-related grade 2-4 adverse events were more common in the ATV/r-treated (23%) compared to the ATV-treated (13%) group; the most frequently reported was increased serum bilirubin (6% of ATV-treated subjects vs 14 % of ATV/r-treated subjects). During the extension phase, 3% (11/369) of subjects met protocol-defined VF (5 ATV-treated and 6 ATV/ r-treated subjects); one ATV/r-treated subject had treatment-emergent major viral resistance-associated mutations. The median change in fasting triglycerides from baseline to week 144 was significantly different (P=.001) in the ATV-treated (-8.5 mg/dL) compared to the ATV/r-treated (28.5 mg/dL) groups. CONCLUSIONS: These long-term study results demonstrate that ATV in combination with ABC/3TC is a potent, well-tolerated regimen in patients who have achieved initial suppression on a ritonavir-boosted regimen.

Safety and efficacy of a 36-week induction regimen of abacavir/lamivudine and ritonavir-boosted atazanavir in HIV-infected patients.

PURPOSE: The ARIES study assessed safety and efficacy of an induction regimen with atazanavir/ritonavir (ATV/RTV) + abacavir/lamivudine (ABC/3TC) followed by simplification to ATV + ABC/3TC in antiretroviral-naïve patients. METHODS: This report includes a noncomparative analysis of all patients in the induction phase of the ARIES study through 36 weeks (clinicaltrials.gov: NCT00440947). This open-label study included 515 antiretroviral-naïve,HLA-B*5701-negative patients receiving a regimen of ATV 300 mg, RTV 100 mg, and ABC/3TC 600 mg/300 mg once daily for 36 weeks; eligible patients were then randomized to continue the induction regimen or simplify to ATV 400 mg plus ABC/3TC 600 mg/300 mg once daily. RESULTS: Eighty-six percent (442/515) of patients completed 36 weeks on study; 80% (410/515) achieved HIV RNA <50 copies/mL (84% and 76% of patients with baseline HIV RNA of < and >or=100,000 copies/mL achieved this endpoint). Virologic failure (VF) was uncommon (3%); treatment-emergent major protease inhibitor and nucleoside reverse transcriptase inhibitor mutations were detected in 0/15 and 4/15 patients, respectively. Median CD4+ cell increase was 171 (range, -176 to 718) cells/mm(3). Hyperbilirubinemia (13%), diarrhea (4%), nausea (2%), and rash (2%) were the most frequent drug-related Grade 2-4 adverse events. Few adverse events (3%) led to study discontinuation. CONCLUSIONS: Induction with ATV/RTV + ABC/3TC once daily provides an efficacious and well-tolerated regimen for the initial treatment of HIV.

Changes over time in creatinine clearance and comparison of emergent adverse events for HIV-positive adults receiving standard doses (300 mg/day) of lamivudine-containing antiretroviral therapy with baseline creatinine clearance of 30-49 vs ≥50 mL/min.

A retrospective analysis of the randomized controlled DART (Development of AntiRetroviral Therapy in Africa; ISRCTN13968779) trial in HIV-1-positive adults initiating antiretroviral therapy with co-formulated zidovudine/lamivudine plus either tenofovir, abacavir, or nevirapine was conducted to evaluate the safety of initiating standard lamivudine dosing in patients with impaired creatinine clearance (CLcr). Safety data collected through 96 weeks were analyzed after stratification by baseline CLcr (estimated using Cockcroft-Gault) of 30-49 mL/min (n = 168) versus ≥50 mL/min (n = 3,132) and treatment regimen. The Grade 3-4 adverse events (AEs) and serious AEs (for hematological, hepatic and gastrointestinal events), maximal toxicities for liver enzymes, serum creatinine and bilirubin and maximum treatment-emergent hematology toxicities were comparable for groups with baseline CLcr 30-49 versus CLcr≥50 mL/min. No new risks or trends were identified from this dataset. Substantial and similar increases in the mean creatinine clearance (>25 mL/min) were observed from baseline though Week 96 among participants who entered the trial with CLcr 30-49 mL/min, while no increase or smaller median changes in creatinine clearance (<7 mL/min) were observed for participants who entered the trial with CLcr ≥50 mL/min. Substantial increases (> 150 cells/ mm3) in mean CD4+ cells counts from baseline to Week 96 were also observed for participants who entered the trial with CLcr 30-49 mL/min and those with baseline CLcr ≥50 mL/min. Though these results are descriptive, they suggest that HIV-positive patients with CLcr of 30-49 mL/min would have similar AE risks in comparison to patients with CLcr ≥50 mL/min when initiating antiretroviral therapy delivering doses of 300 mg of lamivudine daily through 96 weeks of treatment. Overall improvements in CLcr were observed for patients with baseline CLcr 30-49 mL/min.

Effect of tenofovir subtraction on HIV plasma viraemia, CD4+ T-cell count and resistance in a patient with baseline K65R and M184V mutations.

In vitro, the reverse transcriptase mutation K65R can simultaneously reduce drug susceptibility, replicative capacity and restrict HIV-1 replication. Here, we assessed the effect of tenofovir discontinuation for a patient receiving antiretroviral therapy whose HIV-1 had a dominant K65R/M184V genotype. Although limited by the single-case nature, the data support a hypothesis that there is no HIV viral RNA or CD4+ T-cell count benefit of taking tenofovir for experienced patients with genotypic evidence of K65R/M184V.

Fosamprenavir or atazanavir once daily boosted with ritonavir 100 mg, plus tenofovir/emtricitabine, for the initial treatment of HIV infection: 48-week results of ALERT.

BACKGROUND: Once-daily (QD) ritonavir 100 mg-boosted fosamprenavir 1400 mg (FPV/r100) or atazanavir 300 mg (ATV/r100), plus tenofovir/emtricitabine (TDF/FTC) 300 mg/200 mg, have not been compared as initial antiretroviral treatment. To address this data gap, we conducted an open-label, multicenter 48-week study (ALERT) in 106 antiretroviral-naïve, HIV-infected patients (median HIV-1 RNA 4.9 log10 copies/mL; CD4+ count 191 cells/mm3) randomly assigned to the FPV/r100 or ATV/r100 regimens. RESULTS: At baseline, the FPV/r100 or ATV/r100 arms were well-matched for HIV-1 RNA (median, 4.9 log10 copies/mL [both]), CD4+ count (mean, 176 vs 205 cells/mm3). At week 48, intent-to-treat: missing/discontinuation = failure analysis showed similar responses to FPV/r100 and ATV/r100 (HIV-1 RNA < 50 copies/mL: 75% (40/53) vs 83% (44/53), p = 0.34 [Cochran-Mantel-Haenszel test]); mean CD4+ count change-from-baseline: +170 vs +183 cells/mm3, p = 0.398 [Wilcoxon rank sum test]). Fasting total/LDL/HDL-cholesterol changes-from-baseline were also similar, although week 48 median fasting triglycerides were higher with FPV/r100 (150 vs 131 mg/dL). FPV/r100-treated patients experienced fewer treatment-related grade 2-4 adverse events (15% vs 57%), with differences driven by ATV-related hyperbilirubinemia. Three patients discontinued TDF/FTC because their GFR decreased to <50 mL/min. CONCLUSION: The all-QD regimens of FPV/r100 and ATV/r100, plus TDF/FTC, provided similar virologic, CD4+ response, and fasting total/LDL/HDL-cholesterol changes through 48 weeks. Fewer FPV/r100-treated patients experienced treatment-related grade 2-4 adverse events.

Changes from 2000 to 2009 in the Prevalence of HIV-1 Containing Drug Resistance-Associated Mutations from Antiretroviral Therapy-Naive, HIV-1-Infected Patients in the United States.

Pre-existing HIV drug resistance can jeopardize first-line antiretroviral therapy (ART) success. Changes in the prevalence of drug resistance-associated mutations (DRMs) were analyzed from HIV-infected, ART-naive, U.S. individuals seeking ART treatment from 2000 to 2009. HIV DRM data from 3,829 ART-naive subjects were analyzed by year of sample collection using International Antiviral Society-United States (IAS-USA) and World Health Organization (WHO) "surveillance" DRM definitions; minor IAS-USA-defined DRMs were excluded. IAS-USA DRM prevalence between 2000 and 2009 was 14%, beginning with 8% in 2000 and 13% in 2009. The greatest incidence was observed in 2007 (17%). Overall, IAS-USA-defined non-nucleoside reverse transcriptase inhibitor (NNRTI) DRMs were 9.5%; nucleoside reverse transcriptase inhibitor (NRTI): 4%, and major protease inhibitor (PI): 3%. The most frequently detected IAS-USA-defined DRMs by class were NNRTI: K103N/S (4%), NRTI: M41L (1.5%), and PI: L90M (1%). Overall, WHO-defined DRM prevalence was 13% (5% in 2000; 13% in 2009). By class, NNRTI prevalence was 6%, NRTI: 6%, and PI: 3.2%. The most frequent WHO-defined DRMs were NRTI: codon T215 (3.0%), NNRTI: K103N/S (4%), and PI: L90 (1%). WHO-defined NNRTI DRMs declined significantly (p = .0412) from 2007 to 2009. The overall prevalence of HIV-1 containing major IAS-USA or WHO-defined DRMs to ≥2 or ≥3 classes was 2% and <1%, respectively. The prevalence of HIV-1 with WHO-defined dual- or triple-class resistance significantly declined (p = .0461) from 2008 (4%) to 2009 (<1%). In this U.S. cohort, the prevalence of HIV-1 DRMs increased from 2000 onward, peaked between 2005 and 2007, and then declined between 2008 and 2009; the detection of WHO-defined dual- or triple-class DRM similarly decreased from 2008 to 2009.

A Two-Way Steady-State Pharmacokinetic Interaction Study of Doravirine (MK-1439) and Dolutegravir.

INTRODUCTION: Doravirine, a non-nucleoside reverse-transcriptase inhibitor in development for the treatment of patients with human immunodeficiency virus-1 infection, has potential to be used concomitantly in antiretroviral therapy with dolutegravir, an integrase strand transfer inhibitor. The pharmacokinetic interactions between these drugs were therefore assessed. METHODS: Oral formulations of doravirine and dolutegravir were dosed both individually and concomitantly once daily in healthy adults. Twelve subjects (six were male), 23-42 years of age, were enrolled and 11 completed this phase I, open-label, three-period, fixed-sequence study per protocol; one subject was discontinued for a positive cotinine test at admission to period 2. In period 1, dolutegravir 50 mg was administered for 7 days. After a 7-day washout, doravirine 200 mg was dosed for 7 days in period 2, followed (without washout) by both doravirine and dolutegravir simultaneously for 7 days in period 3. Plasma samples were taken to determine dolutegravir and doravirine concentrations. RESULTS: The steady-state concentration 24 h post-dose (C24) of dolutegravir was not substantially altered by co-administration of doravirine multiple doses; area under the plasma concentration-time curve from dosing to 24 h post-dose (AUC0-24), maximum concentration (C max), and C24 geometric mean ratios were 1.36, 1.43, and 1.27, respectively. The pharmacokinetics of doravirine was not affected by multiple doses of dolutegravir (geometric mean ratios: 1.00, 0.98, and 1.06 for AUC0-24, C24, and C max, respectively). Both drugs were generally well tolerated. CONCLUSION: The results of this study demonstrate that concomitant administration of doravirine and dolutegravir in healthy subjects causes no clinically significant alteration in the pharmacokinetic and safety profiles of the two drugs, thereby supporting further evaluation of co-administration of these agents for human immunodeficiency virus-1 treatment.

Response by gender of HIV-1-infected subjects treated with abacavir/lamivudine plus atazanavir, with or without ritonavir, for 144 weeks.

PURPOSE: The 144-week results of the open-label, multicenter Atazanavir/Ritonavir Induction with Epzicom Study (ARIES) were stratified by gender to compare treatment responses. METHODS: A total of 369 HIV-infected, antiretroviral-naïve subjects receiving once-daily abacavir/lamivudine + atazanavir/ritonavir (ATV/r) whose HIV-1 RNA was <50 copies/mL by week 30 were randomized 1:1 at week 36 to maintain or discontinue ritonavir for 108 subsequent weeks. Between- and within-treatment gender-related efficacy and safety differences were analyzed. RESULTS: Subjects were 85% male; 64% white; and had a mean age of 39 years, baseline median HIV-1 RNA of 114,815 copies/mL, and median CD4+ cell count of 198 cells/mm3. Gender (ATV [n=189]: 29 females/160 males; ATV/r [n=180]: 25 females/155 males) and most other demographics were similar between groups; more females than males were black (65% vs 25%) and fewer females had baseline HIV-1 RNA ≥100,000 copies/mL (41% vs 58%). At week 144, no significant differences between genders were observed in proportion maintaining HIV-1 RNA <50 copies/mL (ATV, 79% vs 77%; ATV/r, 60% vs 75%) or <400 copies/mL (ATV, 83% vs 84%; ATV/r, 68% vs 82%) (intent-to-treat-exposed: time to loss of virologic response analysis); median CD4+ change from baseline (ATV, +365 vs +300 cells/mm3; ATV/r, +344 vs +301 cells/mm3); proportion with treatment-related grade 2-4 adverse events (baseline to week 144: ATV, 41% vs 31%; ATV/r, 36% vs 43%; weeks 36 to 144: ATV, 14% vs 13%; ATV/r, 24% vs 23%); or proportion developing fasting lipid changes. Female and male virologic failure rates (ATV, 0 vs 5; ATV/r, 2 vs 4) and proportions completing the study were similar during the extension phase. Primary withdrawal reasons were loss to follow-up and pregnancy for females and loss to follow-up and other for males. CONCLUSION: Over 144 weeks, no significant gender differences were observed in efficacy, safety, or fasting lipid changes with abacavir/lamivudine +ATV or abacavir/lamivudine +ATV/r.

Improvements in lipoatrophy, mitochondrial DNA levels and fat apoptosis after replacing stavudine with abacavir or zidovudine.

OBJECTIVE: To determine if stavudine (alpha4T)-associated mitochondrial toxicity could be reversed by substitution with another nucleoside reverse transcriptase inhibitor. As apoptosis and dysfunction of electron transport chain (ETC) activities may underlie mitochondrial toxicity, these parameters were also evaluated. DESIGN: The 16 participants (on d4T for >3 years; with lipoatrophy and/or hyperlactatemia) substituted abacavir or zidovudine for stavudine in their antiretroviral regimen. Key parameters including dual-energy X-ray absorptiometry (DEXA) scans, fat apoptosis, mitochondrial DNA (mtDNA) content in peripheral blood mononuclear cells (PBMC), skeletal muscle and fat, as well as skeletal muscle mitochondrial ETC activities were evaluated at study entry and at 48 weeks after the substitution. METHODS: Quantitative PCR was used to evaluate mtDNA levels and the presence of deletions/rearrangements; CLIA-validated methods for ETC activities; terminal deoxynucleotidyl transferase dUTP-digoxigenin nick-end labeling assays to evaluate adipocyte apoptosis; and DEXA scans to measure changes in body fat. RESULTS: MtDNA was depleted at study entry in muscle, adipose tissue and PBMC but levels rebounded with respective mean increases of 141%, 146%, and 369% at week 48. Corresponding fat improvements were noted with DEXA increases of 21%, 11%, and 16% in arm, leg, and trunk, respectively. Quantitative adipocyte apoptosis were significantly increased at baseline (P < 0.01 versus HIV-negative controls), with a significant reduction at week 48 (P < 0.05 versus baseline). Mean values for seven mitochondrial enzyme activities assays at entry indicated substantial loss of function (48% to 85% of controls) with significant improvement of complex I activity by week 48. CONCLUSIONS: Substitution of stavudine with abacavir or zidovudine improves mitochondrial indices and fat apoptosis in the setting of lipoatrophy.

Treatment-Emergent Mutations and Resistance in HIV-Infected Children Treated with Fosamprenavir-Containing Antiretroviral Regimens.

Treatment-emergent mutations and drug resistance were analyzed in virus from HIV-infected children meeting virologic failure (VF) criteria over 48 weeks following treatment with unboosted fosamprenavir or fosamprenavir/ritonavir-containing regimens in studies APV20002 and APV29005. Both antiretroviral therapy (ART)-naïve and ART-experienced patients were enrolled. Patients met VF criteria by either failing to suppress HIV-RNA to <400 copies/mL through week 24 or after confirmed viral rebound (≥400 copies/mL) anytime through week 48. Viral isolates were analyzed for treatment-emergent mutations or reduced drug susceptibility. Through week 48, 25/109 (23%) of APV29005 and 9/54 (17%) APV20002 study patients met VF. VF was more common in ART-experienced patients (68% and 78%, respectively). Major or minor treatment-emergent mutations were detected at VF in virus from 3 patients receiving unboosted fosamprenavir-containing regimens and in virus from 10 patients receiving fosamprenavir/ritonavir-containing regimens across the two studies. Major protease inhibitor mutations and the reverse transcriptase mutation M184V were detected at VF in virus from 4 and 5 patients, respectively, across both studies. Reduced drug susceptibility to any drug emerged in virus from 9 patients at VF, although reduced fosamprenavir susceptibility emerged in virus from only 4 patients (2 ART-naïve and 2 ART-experienced). No cross-resistance to the protease inhibitor darunavir was observed. In conclusion, given the high proportion of ART-experienced children (71%) in these two studies, the overall incidence of children meeting VF criteria through 48 weeks was relatively low (21%) and development of fosamprenavir reduced drug susceptibility at VF was uncommon, further supporting the use of fosamprenavir-containing ART regimens in HIV-infected children.

Mutations linked to drug resistance, human immunodeficiency virus type 1 biologic phenotype and their association with disease progression in children receiving nucleoside reverse transcriptase inhibitors.

BACKGROUND: Few data are available concerning the impact of antiretroviral resistance in response to antiviral therapy in children. We evaluated the development of antiretroviral genotypic resistance and clinical outcome in a subgroup of children involved in a prospective antiretroviral therapy trial (Pediatric AIDS Clinical Trials Group Protocol 152). DESIGN: We studied 26 matched case/control pairs. A case was defined as having clinical disease progression during the study period; controls did not have disease progression. Cases and controls were matched by age and CD4+ cell count at baseline. Matched pairs received treatment with zidovudine (9 pairs), didanosine (12 pairs) or combined therapy (5 pairs). Multiple codons of the reverse transcriptase coding region (41, 67, 70, 74, 151, 184, 210, 215 and 219) were analyzed. Patients were evaluated for CD4+ cell count, HIV-1 viral load and HIV-1 biologic phenotype at baseline and clinical endpoint. RESULTS: The presence of mutations associated with resistance after nucleoside antiretroviral therapy (P = 0.039) and syncytium-inducing phenotype (P = 0.031), were significantly associated with increased risk of clinical disease progression. The mean difference in HIV-1 RNA levels between cases and their matched controls after nucleoside antiretroviral therapy was 0.77 log10 copies/ml higher for cases (P = 0.003). The median difference between cases and controls for CD4+ cell count after nucleoside antiretroviral therapy was 349 cells/mm3 lower for cases (P < 0.001). CONCLUSIONS: In this small prospective study of HIV-infected children, mutations in the reverse transcriptase coding region, syncytium-inducing viral phenotype, higher HIV-1 RNA load and lower CD4+ cell count were significantly correlated with increased risk of HIV clinical disease progression.

Stavudine-associated peripheral neuropathy in zidovudine-naïve patients: effect of stavudine exposure and antiretroviral experience.

A post hoc analysis of safety data from study protocol NZT40012 assessed the incidence of conditions defined by the Centers for Disease Control and Prevention in 86 zidovudine-naïve, antiretroviral-experienced patients with HIV-1 infection who responded poorly (plasma HIV-1 RNA > 1000 copies/mL) despite at least 4 months' treatment with stavudine-containing regimens. Peripheral neuropathy occurred in 21%; other conditions were seen less frequently (candidiasis [13%], herpes zoster [12%], diarrhea lasting > 1 month [9%], Pneumocystis carinii pneumonia [9%], and wasting syndrome [8%]). The incidence of peripheral neuropathy rose significantly with the number of drugs comprising treatment regimens (> or = 4 vs 1-3; P = .013) and tended to be higher in patients with longer exposure to stavudine (29% with > or = 24 months' exposure vs 13% with < 24 months). Because peripheral neuropathy was observed with such high frequency, vigilance for signs and symptoms of this condition appears warranted if stavudine-containing regimens are to be continued.

Pharmacokinetics, safety and antiviral activity of fosamprenavir/ritonavir-containing regimens in HIV-infected children aged 4 weeks to 2 years-48-week study data.

BACKGROUND: Pharmacokinetics, safety and antiviral activity of fosamprenavir (FPV) with ritonavir (RTV) twice daily were evaluated in HIV-1-infected infants and children 4 weeks to <2 years over 48 weeks. METHODS: Results from intensive pharmacokinetic sampling of subjects enrolled in single dose visits was used to determine individualized dosing for the first 6-10 subjects in each of 2 cohorts (4 weeks to <6 months, 6 months to <2 years); steady state pharmacokinetic data were then used to select the dosage regimen for the remaining subjects recruited to the cohort. Intensive pharmacokinetic sampling was performed at week 2 or 8; predose samples were collected every 4-12 weeks thereafter. Safety and plasma HIV-1 RNA were monitored every 4-12 weeks. RESULTS: Fifty-nine subjects received study medication. FPV 45 mg/kg boosted with RTV 7 to 10 mg/kg BID achieved average plasma amprenavir area under curve(0-τ) values 26% to 28% lower and Cmax similar to historical adult data for FPV/RTV 700/100 mg BID; amprenavir Cτ values were lower in the subjects <6 months of age. At week 48, 35 of 54 (65%) subjects had achieved plasma HIV-1 RNA <400 copies/mL and 33 of 54 (61%) had plasma HIV-1 RNA values <50 copies/mL. The most common adverse events were diarrhea, upper respiratory tract infection, gastroenteritis and otitis media. CONCLUSIONS: Final FPV/RTV dosing regimens achieved plasma amprenavir exposures comparable with those from regimens approved in adults, with the exception of trough exposures in the <6-month-old infants. The FPV/RTV regimens led to viral suppression in 61% of patients and were generally well tolerated.

Pharmacokinetics and 48-week safety and antiviral activity of fosamprenavir-containing regimens in HIV-infected 2- to 18-year-old children.

BACKGROUND: Pharmacokinetics, safety and antiviral activity of twice-daily fosamprenavir with or without ritonavir were evaluated in 2- to 18-year-old protease inhibitor-naïve and -experienced HIV-1-infected children. METHODS: Serial pharmacokinetic samples were collected at week 2 and predose samples every 4-12 weeks. Safety and plasma HIV-1 RNA were monitored every 4-12 weeks. RESULTS: Twenty protease inhibitor-naïve 2- to <6-year-old subjects received antiretroviral treatment including unboosted fosamprenavir twice-daily, whereas 89 protease inhibitor-naïve and -experienced 2- to 18-year-old subjects received fosamprenavir/ritonavir-containing therapy twice-daily. Median fosamprenavir exposure was 891 days (range 15-1805 days), with 88% exposed >48 weeks. Twice-daily doses of fosamprenavir/ritonavir 23/3 mg/kg in 2- to <6-year olds, 18/3 mg/kg in ≥6-year olds and 700/100 mg in adolescents achieved plasma amprenavir exposures comparable with or higher than 700/100 mg twice-daily in adults while fosamprenavir 30 mg/kg twice-daily in 2- to <6-year olds led to exposures higher than 1400 mg twice-daily in adults. The proportion of subjects with HIV-1 RNA <400 copies/mL at week 48 was 60% for fosamprenavir and 53-74% for fosamprenavir/ritonavir (intent-to-treat [exposed], snapshot analysis). Median increases in absolute and relative (percentage) CD4 counts from baseline to week 48 occurred in both the fosamprenavir (340 cells/mm; 8%) and fosamprenavir/ritonavir group (190 cells/mm; 8%). The most common adverse events were vomiting, cough, and diarrhea; 18 subjects experienced serious adverse events, including 9 with suspected abacavir hypersensitivity. CONCLUSIONS: Fosamprenavir regimens administered to HIV-1-infected children aged 2-18 years were generally well-tolerated and provided sustained antiviral activity over 48 weeks, with plasma amprenavir exposures comparable with or higher than adults.