Long-term efficacy and safety of fosamprenavir plus ritonavir versus lopinavir/ritonavir in combination with abacavir/lamivudine over 144 weeks.

PURPOSE: The KLEAN study extension assessed the long-term efficacy and safety of fosamprenavir-ritonavir (FPV/r) and lopinavir-ritonavir (LPV/r), both administered with abacavir/lamivudine (ABC/3TC) fixed dose combination, over 144 weeks. METHODS: KLEAN was an open-label, noninferiority study that randomised antiretroviral-naïve patients to FPV/r twice daily (bid) or LPV/r bid with ABC/3TC once daily (qd). Patients with a viral load of <400 copies/mL at Week 48 were eligible to participate in the KLEAN study extension (up to 144 weeks) and continued with their previously randomised therapy. RESULTS: The KLEAN study extension (48 to 144 weeks) randomized 199 patients. The proportion of TLOVR responders (HIV-1 RNA <50 copies/mL) at Week 144 was 73% and 60% in the FPV/r and LPV/r arms, respectively. The proportion of TLOVR responders (<50 copies/mL) was the same irrespective of baseline HIV-1 RNA (>100,000 or 100,000 copies/mL). The Week 144 median (interquartile range) change from baseline CD4+ cell count was 300 (236-433) cells/mm3 and 335 (225-444) cells/mm3 in the FPV/r and LPV/r arms, respectively. Diarrhea was the most frequently reported adverse event. A small proportion of patients (FPV/r, 13%; LPV/r, 9%) discontinued study medication due to adverse events. Three patients (FPV/r, 1; LPV/r, 2) experienced virological failure between Week 48 and Week 144. CONCLUSION: The findings of the KLEAN study extension (48 to 144 weeks) support durable viral suppression with both FPV/r and LPV/r treatment regimens when used in combination with ABC/3TC irrespective of viral load at baseline. Both regimens were well tolerated and had similar safety profiles.

Evaluation of a real-time nucleic acid sequence-based amplification assay using molecular beacons for detection of human immunodeficiency virus type 1.

We evaluated the performance characteristics of a new, real-time nucleic acid sequence-based amplification (NASBA) assay that incorporates molecular beacon technology for detection of human immunodeficiency virus type 1 (HIV-1). The quantitative results were comparable to those obtained with three leading commercially available assays. The analytical sensitivity was 37 IU/ml. The NASBA assay detected clinically relevant recombinant viruses and all group M HIV-1 subtypes.

Immune reconstitution in human immunodeficiency virus-infected children receiving highly active antiretroviral therapy: a cohort study.

BACKGROUND: Highly active antiretroviral therapy (HAART) has brought about rapid declines in HIV-1 RNA concentrations and an increase in CD4+ counts in HIV-1-infected children. These changes are often accompanied by clinical improvement; however, the extent to which immune reconstitution occurs is not known. DESIGN: We compared two cohorts (n = 35) of HIV-1-infected children to evaluate the effects of HAART on immune recovery. Cohort 1 (C1) included clinically well children receiving HAART with a CD4 >22% at study initiation. Before HAART all children had moderately to severely suppressed immune function by CDC criteria (CD4 <25%) or CDC Category B or C disease. Cohort 2 (C2) included children with no current or past evidence of immunosuppression based on CDC criteria (CD4 >25%) and no evidence of clinical disease. Children in C2 were receiving a non-HAART regimen. METHODS: Immunophenotyping was performed to characterize CD4+ and CD8+ subsets with regard to maturation and activation. T cell rearrangement excision circles (TRECs) were measured to quantify recent thymic emigrants. RESULTS: No difference was found in percent CD4+ or percent CD8+ T cells or maturation markers between C1 and C2. There was significantly less expression of activation markers in both CD4+ and CD8+ cells in C1. There was no difference in TREC production between C1 and C2. CONCLUSION: Moderately to severely suppressed HIV-1-infected children receiving HAART are able to reconstitute their immune systems to a degree that is indistinguishable from that of stable, CDC Class A1 HIV-1-infected children with regard to CD4+ and CD8+ T cell subsets, expression of cellular maturation markers and TREC production.

Treatment intensification with abacavir in HIV-infected patients with at least 12 weeks previous lamivudine/zidovudine treatment.

OBJECTIVES: To demonstrate that lamivudine and zidovudine, given separately (lamivudine/zidovudine) or as a single combination tablet (Combivir), had equivalent efficacy. To evaluate the safety and antiretroviral activity of intensification with abacavir in patients treated with lamivudine/zidovudine for > or = 12 weeks. DESIGN: A 12-week, equivalence study of lamivudine/ zidovudine versus Combivir. Patients who completed this study could enter a 48-week, intensification study of Combivir plus abacavir. METHODS: In the equivalence study, treatment-naive patients were assessed for HIV-1 RNA, CD4 cell count and genotype. The same assessments plus phenotype were made in the intensification study. Serious adverse events were recorded in the equivalence study and all adverse events in the intensification study. RESULTS: Lamivudine/zidovudine (n=40) and Combivir (n=35) gave equivalent reductions in plasma HIV-1 RNA levels at week 12. An identical proportion of patients (74%) in each treatment group harboured virus with the M184V mutation after 12 weeks. Fifty-two patients entered the intensification study and 44 completed 48 weeks of treatment. At the time of intensification with abacavir, all 35 patients with evaluable isolates harboured HIV-1 containing M184V. Addition of abacavir to Combivir led to further decreases in plasma HIV-1 RNA and increases in CD4 cell counts compared with the start of intensification (P<0.001 at week 48). After 48 weeks of triple therapy, multi-nucleoside resistance mutations at codons 69 and 151 were not detected in any patients. All treatment regimens were generally well tolerated. CONCLUSION: Lamivudine/zidovudine and Combivir have equivalent antiretroviral activity over 12 weeks. Adding abacavir to Combivir can be a safe and effective therapeutic option for patients, including those harbouring virus with the M184V mutation.

Substitution of a commercially available, RNA extraction procedure in an HIV-1 genotyping system improves sensitivity and allows reduced sample volume.

The use is described of a commercially available, silica-based extraction procedure for HIV-1 RNA that can be substituted for the extraction procedure supplied with a commercially available, PCR-based genotyping kit for HIV-1. The advantages of using this alternative, commercially available extraction procedure include the following: (1) reduced safety concerns, due to inactivation of virus in the initial step of the extraction procedure; (2) enhanced sensitivity, allowing the use of plasma with HIV-1 RNA levels of less than 2000 copies/ml; (3) improved yield, allowing a 60% reduction in plasma volume; and (4) convenience and improved reproducibility, with a single extraction providing RNA suitable for PCR-based sequencing and for quantitation of HIV-1 RNA levels.

Rapid detection of the HIV type 1 reverse transcriptase codon T215Y by reverse transcription-polymerase chain reaction with fluorogenic probes.

Early detection of viral mutations, particularly those mutations associated with cross-resistance to antiretroviral drugs, is critical both for understanding the mechanism of drug resistance and for the clinical management of patients infected with HIV-1. One of the frequently observed mutations in the HIV-1 reverse transcriptase (RT)-coding region is ACC --> TAC at codon 215, resulting in a change of wild-type threonine (T) to tyrosine (Y); this mutation has been associated with decreased phenotypic susceptibility to zidovudine (ZDV). We describe a technique for the detection of the T215Y mutation using reverse transcription-polymerase chain reaction (RT-PCR) amplification of viral sequences and a 5' nuclease assay requiring fluorogenic probes. In addition to detecting the presence of the ACC --> TAC mutation at codon 215, this assay provides an increased ability to detect low levels of mutant species in a mixed population, relative to conventional sequencing. Further advantages of this technique include the rapid and high-throughput nature of the assay, the accuracy of the assay relative to conventional DNA sequencing, and the convenience of combining RT-PCR virus amplification with the allelic discrimination assay, without the need for purification of PCR products.

Evaluation of surrogate markers and clinical outcomes in two-year follow-up of eighty-six human immunodeficiency virus-infected pediatric patients.

OBJECTIVES: To evaluate the prognostic value of surrogate markers (HIV RNA copy number, CD4 counts and CDC clinical and immunologic categories) in HIV-infected children through a 2-year period. METHODS: Eighty-six HIV-infected children followed by the Duke Pediatric HIV Clinic in the fall of 1994 were evaluated for plasma HIV RNA concentration (viral load), CD4 lymphocyte percentage, age, antiretroviral treatment status and CDC clinical and immunologic categories. Follow-up evaluations were performed for approximately 2 years, and the time to progression to a new CDC category C diagnosis or death was noted. RESULTS: Of 86 children 22 had progression to new Category C diagnosis or death. Seven children died, 17 had a new Category C diagnosis and 2 had both. Among children who progressed, the median CD4 percentage at entry was 3% (absolute count, 75 cells/mm3), whereas children who had no disease progression entered with a median of 29% (868 cells/mm3). The overall median viral load at study entry was 4.58 log10 copies/ml (38,019 copies/ml, with a range of 1.7 to 6.78 logs). Children who had no disease progression had a median log copy number of 4.43, whereas 5.18 was the median for children whose disease progressed. Log copy number declined over time in children < 3 years of age, whereas it remained fairly consistent for children 3 years or older. Progression rates were determined by entry plasma HIV RNA concentration quartiles [quartile boundaries < 4.18, 4.58, > 5.08 log RNA copy/ml (< 15,136, 38,019 and > 120,226 copies/ml, respectively)]. Progression rates by quartile were 0 of 21, 4 of 22, 5 of 21 and 13 of 22. Kaplan-Meier survival curves defined by CD4% less than or greater than 15 and log RNA less than or greater than 5.0 (100,000) revealed that patients with CD4% less than 15 and plasma HIV RNA concentration > 5 log10 copies/ml did least well: 11 of 12 (92%) had a progression event at a median of 179 days. Patients with a high CD4 percentage and high viral load, or a low CD4 percentage and low viral load did similarly; 5 of 14 (36%) and 4 of 12 (33%) had progression events, respectively. Patients with high CD4 percentage and low viral load did best: only 2 of 48 (4%) had a progression event. CONCLUSIONS: The two most significant prognostic indicators of disease progression were the initial CD4 percentage and the plasma HIV RNA concentration, and a combination of CD4 percentage and virus load best predicted which children had progression events. Progression was less common in children who had < 100,000 HIV RNA copies/ml initially (6 of 60 vs. 16 of 26; P < 0.001; relative risk 0.16). Therefore it seems reasonable that in a child for whom complete suppression is not possible, a threshold of 100,000 (5 log10 copies/ml) can be used to mandate a change in therapy.

Effect of influenza immunization on immunologic and virologic characteristics of pediatric patients infected with human immunodeficiency virus.

OBJECTIVES: We evaluated the responses of HIV-infected children to a single dose of split-virus influenza vaccine and the relationship to viral load and other characteristics. METHODS: Fifty-three HIV-infected children ages 1.8 to 13.2 years were given influenza vaccine for the 1994 to 1995 influenza season (Wyeth-Ayerst: A/Texas H1N1, A/Shangdong H3N2 and B/Panama). Immunologic and virologic factors were assessed at the time of and 2 to 10 weeks after immunization. RESULTS: The differences between pre- and postimmunization CD4+ counts, CD4+:CD8+ ratios and viral load were not significant. Thirty-one of 53 children (58.4%) had a > 2-fold increase and 16 of 53 (30%) had a 4-fold rise in their postimmunization antibody titers for at least one component of the vaccine. Influenza immunization in the 1993 to 1994 flu season and administration of intravenous immunoglobulin around the time of immunization was not associated with immune response to the vaccine. Factors that were negatively associated with antibody response included increased time between samples (P = 0.004) and decreased preimmunization CD4+:CD8+ ratio (P = 0.02). CONCLUSIONS: Influenza immunization in this population is safe, and a positive antibody response to influenza immunization is not associated with significant clinical events or change in HIV-1 plasma viral burden.

Zidovudine resistance, syncytium-inducing phenotype, and HIV disease progression in a case-control study. The VA Cooperative Study Group.

A case-control study of patients with progressive (cases) or nonprogressive (controls) disease was designed to determine the association among disease progression, zidovudine sensitivity, and syncytium-inducing phenotype. Viral isolates were screened for sensitivity to zidovudine using a peripheral blood mononuclear cell-based assay and for syncytium-inducing (SI) phenotype in MT2 cell culture. Thirty-four patients, whose disease progressed to AIDS or whose CD4 cell numbers fell < 200 cells/mm3, were matched with 34 patients whose conditions had not progressed or whose CD4 cell numbers remained > 200 cells/mm3. Virus was successfully cultured from both the progressor and the nonprogressor in 17 of these 34 matched case-control pairs. In six of the 17 pairs, virus isolated from the progressor had an IC50 (50% inhibitory concentration) for zidovudine > 1 microM and at least threefold greater than the IC50 of virus isolated from the matched nonprogressor (p = 0.04). In 16 of these 17 pairs the virus isolated from the progressor had the SI phenotype, indicative of high cytopathogenicity, while the virus from the matched nonprogressor had a non-syncytium-inducing phenotype (p < 0.0001). Zidovudine therapy did not appear to select for the SI phenotype in this patient population. A statistically significant association between high-level zidovudine resistance and clinical disease progression was demonstrated. A statistically significant association between the SI phenotype and disease progression was demonstrated. The results suggest that disease progression while being treated with zidovudine therapy may be more closely associated with the SI phenotype than with zidovudine resistance.

HIV-1 sensitivity to zidovudine and clinical outcome in children.

In adults with the acquired immunodeficiency syndrome, long-term monotherapy with zidovudine selects for human immunodeficiency virus type 1 (HIV-1) strains with substantially reduced in-vitro susceptibility to the drug. We have assessed the relation between in-vitro resistance to zidovudine and clinical outcome in children, in whom disease progression is more rapid than in adults. We studied 23 children with symptoms of HIV-1 disease during extended monotherapy with zidovudine. An in-vitro assay was used to determine the concentration of zidovudine required to inhibit by 50% the replication of viral isolates (IC50) obtained after 9 to 39 months of treatment. Viral stocks of high enough titre to yield reproducible results were obtained from 19 of the children. During the following 6 months of therapy, 9 children were stable, 7 deteriorated, and 3 died. There was a highly significant relation between decreased zidovudine susceptibility and poor clinical outcome (p less than 0.001) but no relation between IC50 and age at start of therapy or length of time on treatment. Age-adjusted CD4 lymphocyte counts were lower at the start of treatment (p = 0.02) and at the time of sampling (p = 0.01) in children whose viral isolates had an increased zidovudine IC50. Initial serum p24 antigen levels were not predictive of subsequent emergence of resistant virus, but at the time of sampling for viral sensitivity higher p24 antigen levels were associated with raised IC50 (p = 0.004). The findings suggest that most children who become unresponsive to monotherapy with zidovudine, as judged by clinical criteria, will have changes in in-vitro sensitivity to the drug. In these children, an alternative antiretroviral therapy should be considered.

Resistance to ddI and sensitivity to AZT induced by a mutation in HIV-1 reverse transcriptase.

Serial human immunodeficiency virus type-1 (HIV-1) isolates were obtained from five individuals with acquired immunodeficiency syndrome (AIDS) who changed therapy to 2',3'-dideoxyinosine (ddI) after at least 12 months of treatment with 3'-azido-3'-deoxythymidine (zidovudine, AZT). The in vitro sensitivity to ddI decreased during the 12 months following ddI initiation, whereas AZT sensitivity increased. Analysis of the reverse transcriptase coding region revealed a mutation associated with reduced sensitivity to ddI. When this mutation was present in the same genome as a mutation known to confer AZT resistance, the isolates showed increased sensitivity to AZT. Analysis of HIV-1 variants confirmed that the ddI resistance mutation alone conferred ddI and 2',3'-dideoxycytidine resistance, and suppressed the effect of the AZT resistance mutation. The use of combination therapy for HIV-1 disease may prevent drug-resistant isolates from emerging.