Tickborne encephalitis, southwestern France

We report an autochthonous human case of tickborne encephalitis (TBE) in the Bordeaux area, southwestern France. The patient was a farmer who had severe encephalomyelitis. ELISA and neutralization assay of serum and cerebrospinal fluid established the diagnosis. This potential new endemic focus for TBE virus should be further investigated.

HIV-1 reverse transcriptase (RT) genotypic patterns and treatment characteristics associated with the K65R RT mutation

BACKGROUND

The K65R HIV-1 reverse transcriptase (RT) mutation is a multidrug resistance mutation which may be correlated with specific antiretroviral combinations and with the presence or absence of other RT resistance mutations.

OBJECTIVES

The aims of this study were: (i) to determine the prevalence of the K65R mutation in a cohort of antiretroviral-treated patients; (ii) to study genotypic patterns and treatment characteristics in patients in whom the K65R mutation was present.

STUDY DESIGN

We included in the study all antiretroviral-experienced patients followed up at the Bordeaux University Hospital in 2003 and 2004 for whom an HIV-1 genotypic resistance analysis was available. Information on RT resistance mutations was reported from a hospital database including therapeutic and biological parameters. The prevalence of K65R was investigated for all patients. Genotypic patterns and treatment characteristics were examined at the time of detection of the K65R mutation.

RESULTS

The prevalence of K65R was 1.9% (26 of 1404 patients). K65R was associated with nucleoside RT inhibitor-based regimens in 22 patients, and with tenofovir disoproxil fumarate, lamivudine, didanosine and abacavir in 23, 17, 17 and eight patients, respectively. The M184V and Q151M mutations were the most commonly co-selected substitutions. Thymidine analogue mutations (TAMs) were rarely co-selected with K65R and inversely associated with K65R.

CONCLUSION

The K65R mutation may emerge preferentially in the absence of zidovudine and TAMs, suggesting the possibility of an antagonistic interaction between K65 and TAMs.

Improvement of progressive multifocal leukoencephalopathy after cidofovir therapy in a patient with a destructive polyarthritis

The human neurotropic JC virus (JCV) is responsible for progressive multifocal leukoencephalopathy (PML), an infectious demyelinating brain disease with major morbidity and mortality, usually refractory to treatment. We describe a PML in a 67-year-old woman with a destructive polyarthritis associated with anti-JO1 antibodies treated with corticosteroids. Although glucocorticoid therapy was maintained, administration of cidofovir improved the neurological condition. Our observation demonstrates the expanding clinical importance of JCV in systemic rheumatic diseases, particularly when immunosuppressive agents are used, and neurological symptoms or white matter changes on central nervous system imaging should arouse the suspicion of PML.

Primary Resistance to Enfuvirtide (T20) in recently HIV-1 Infected, Antiretroviral-Naive Patients from the ANRS Aquitaine Cohort

Background

Transmission of HIV-1 variants with resistance to reverse transcriptase (RT) and protease inhibitors has been widely characterized in developed countries. However, no clear evidence of primary resistance to HIV-1 fusion inhibitors has been shown so far. We wished to investigate the possibility of genotypic resistance to enfuvirtide (T20) in a cohort of antiretroviral-naive, recently infected patients.

Methods

We included patients from the Aquitaine Cohort with an estimated date of seroconversion in 2004 and 2005, a plasma sample obtained less than 18 months after seroconversion and no prior history of antiretroviral therapy. RT, protease and gp41 sequences were determined by direct population sequencing from plasma samples and drug resistance mutations were reported.

Results

A total of 55 patients were included in the study. The overall prevalence of transmitted HIV-1 resistance was 20%. Two patients had viruses with resistance mutations to T20. The first case had an N42D mutation in the HR1 region of the gp41, along with transmitted resistance mutations in the protease (D30N, M36I, N88D) and in the RT (M41L, L210W, T215D). The second case had a G36D HR1 mutation, with no evidence of other drug resistance mutations.

Conclusion

We have shown the first cases of primary resistance to T20 in recently infected patients in southwestern France. Epidemiological surveillance of the transmission of drug-resistant HIV-1 should include the resistance to T20.

Interpretation of genotype and pharmacokinetics for resistance to fosamprenavir-ritonavir-based regimens in antiretroviral-experienced patients

In this study, named the Zephir study (Telzir-pharmacokinetics), 121 antiretroviral-experienced human immunodeficiency virus (HIV) patients failing on highly active antiretroviral therapy (HAART) were included in a prospective cohort and received a fosamprenavir-ritonavir (700 mg/100 mg twice a day)-based regimen. The impact of baseline HIV type 1 (HIV-1) mutations, pharmacokinetic (PK) parameters, and genotype inhibitory quotient (GIQ) on the virological response at week 12 (W12) was assessed. HIV reverse transcriptase and protease were sequenced at W0. The response at W12 was defined as<2.3 log10 HIV-1 RNA copies/ml or a virus load decrease of>or=1 log10 copies/ml. W4 amprenavir PK were determined by high-performance liquid chromatography. Patients had a median of nine previous treatments over 8 years. Median W0 values were as follows: 295 CD4+/microl, 4.4 log10 HIV-1 RNA copies/ml, and 6 protease- and 5 nucleotide reverse transcription inhibitor-related mutations. Respective values for minimum concentration of drug in serum (Cmin) and area under the concentration-time curve (AUC) from 0 to 24 h were 1,400 ng/ml and 35 mg.h/ml. At W12, 52% of the patients were successes, with a median decrease of -0.7 log10 HIV-1 RNA copies/ml. The Zephir mutation score included 12 IAS protease mutations associated with poorer virological response: L10I/F/R/V, L33F, M36I, M46I/L, I54L/M/T/V, I62V, L63P, A71I/L/V/T, G73A/C/F/T, V82A/F/S/T, I84V, L90M, and polymorphism mutations I13V, L19I, K55R, and L89M. Comparing<4 versus>or=4 mutations, HIV-1 RNA decreases were -2.3 log10 copies/ml versus -0.1 log10 copies/ml (P<10(-4)) with 93% versus 19% successes (P<10(-4)), respectively. This score predicted W12 failure with 94% sensitivity, versus 31% for the ANRS 2005 algorithm. Cmin (<1,600 ng/ml), AUC (<40 mg.h/ml), and GIQ (<300) values were associated with failure (all P values were <10(-4)). The need to test genotype-based algorithms using different patient databases before their implementation in clinical practice is highlighted. Specific mutations, PK and GIQ, provide relevant information for monitoring fosamprenavir-ritonavir-based HAART.

Outbreak of hepatitis C virus infection during sclerotherapy of varicose veins: long-term follow-up of 196 patients (4535 patient-years)

BACKGROUND/AIMS

The aim of this study was to describe the natural history of a HCV infection outbreak in 196 patients who had sclerotherapy by a same physician and to confirm patient-to-patient transmission using phylogenetic analysis in a large series of patients.

METHODS

Demographic information included clinical and biological parameters. Fibrosis evaluation was performed using liver biopsy or transient elastography. Follow-up was maintained until death, or the end of the observation period. In order to determine if the virus had been transmitted between the HCV genotype 2 patients, sequence analysis was undertaken of a part of the NS5b region of the genomes in samples of patients.

RESULTS

The mean duration of follow-up was 23.1+/-6.7 years (4535 patient-years). In patients with fibrosis evaluation, 55.7% had no or mild fibrosis and 44.3% had significant fibrosis. No patient died from HCV-related disease. Nucleotide sequence analysis of a part of the NS5b region revealed that patients were all infected with the same HCV subtype (genotype 2d). The most evident feature of the tree is the clustering of all patients involved in the outbreak without any unrelated isolates.

CONCLUSION

This study emphasizes the risk for nosocomial spread of HCV during intravenous therapy.

Increasing HIV type 1 polymorphic diversity but no resistance to antiretroviral drugs in untreated patients from Central African Republic: a 2005 study

As the HIV-1 pandemic becomes increasingly complex and as new countries acceed to antiretroviral drugs, the molecular characterization of HIV-1 strains circulating has important implications for vaccine research and for the efficacy of treatments. To follow the evolution of HIV-1 diversity in African countries, we have carried out a molecular analysis of HIV-1 strains collected from 150 HIV-1-positive pregnant women recruited in Bangui, Central African Republic (CAR). We have sequenced reverse transcriptase (RT) and protease (PROT) genes to (1) characterize the subtypes and CRFs, (2) describe the polymorphism of RT and PROT, particularly at the positions of drug resistance mutations in subtype B, and (3) observe potential drug resistance mutations and evaluate the prevalence of isolates bearing such mutations in this untreated population. The results showed that there is a very high and increasing diversity of HIV-1 strains circulating in CAR; out of 117 samples sequenced, we have observed 45 CRF11_cpx, 22 subtypes A1, 13 subtypes G, 7 subtypes CRF01_AE, 3 subtypes B, 3 subtypes CRF02_AG, 2 of each subtype F2 and CRF09_cpx, and one of each subtype D, J, C, H, CRF06_cpx, CRF13_cpx, and CRF19_cpx; the remaining 13 strains showed discordant genomic results suggesting multiple recombinations leading to mosaic viruses. The polymorphism of RT and PROT was high compared to subtype B, particularly at some positions that have been involved in antiretroviral resistance in subtype B, but we could not observe any major resistance mutation in this sample of untreated patients. The prevalence of drug resistance mutations in this population was therefore clearly under the WHO 5% threshold.

Intracellular and plasma efavirenz concentrations in HIV-infected patients switching from successful protease inhibitor-based highly active antiretroviral therapy (HAART) to efavirenz-based HAART (SUSTIPHAR Study)

OBJECTIVES

To assess intracellular and plasma efavirenz concentrations in HIV-infected patients who switched to efavirenz-based highly active antiretroviral therapy (HAART) from successful protease inhibitor-based HAART.

PATIENTS AND METHODS

A total of 49 patients were included in this observational cohort study. At inclusion, all patients had plasma HIV-RNA levels<50 copies/mL and switched to efavirenz combined with two nucleoside reverse transcriptase inhibitors. Intracellular and plasma concentrations were measured 12 h post-dose, 1 month (M1) and 6 months (M6) after starting efavirenz. Virological success (VS) was defined as plasma HIV-RNA level<50 copies/mL within the first 12 months and remaining undetectable at the end of the follow-up.

RESULTS

VS was documented in 48 patients for at least 12 months (range 12-78 months). High inter-patient variabilities of intracellular and plasma efavirenz concentrations were observed (coefficients of variation>40%). At M1 and M6, respectively, median [Q1; Q3] intracellular efavirenz concentrations were 5300 [2830; 11 530] and 6790 [3870; 8790] ng/mL, median plasma efavirenz concentrations were 2050 [1600; 3100] and 2100 [1410; 2500] ng/mL. No correlation was found between intracellular and plasma concentrations. Plasma efavirenz levels exceeded the proposed threshold of 1000 ng/mL in 96% of patients from M1.

CONCLUSIONS

For moderately pre-treated HIV-infected patients with few mutations who switched to efavirenz from previous successful HAART, the proposed plasma efficacy-threshold was reached without any dosage adaptation. VS was maintained beyond 12 months, despite high inter-patient and intra-patient variabilities of intracellular and plasma efavirenz concentrations.

Antiretroviral Efficacy and Virological Profile of a Zidovudine/Lamivudine/Tenofovir Disoproxil Fumarate Combination Therapy in Antiretroviral-Naive Patients

Objective

To study the antiviral efficacy and the mutations selected by a triple therapy with zidovudine (AZT), lamivudine (3TC) and tenofovir disoproxil fumarate (TDF).

Methods

Antiretroviral-naive patients received 300 mg AZT/150 mg 3TC twice a day plus 300 mg TDF once a day in an open pilot study. Follow-up was assessed at baseline therapy (M0) and at months 1, 3, 6, 9 and 12. Reverse transcriptase (RT) genotypic resistance analysis and in selected cases, a recombinant drug susceptibility and replication capacity assay were performed from plasma RNA at baseline and in case of virological failure (VF); that is, rebound of viral load >50 copies/ml on therapy.

Results

Twenty-four patients were included. At baseline, the median CD4+ T-cell count was 443 cells/μl and the median plasma viral load (VL) was 4.38 log10 copies/ml. RT resistance mutations were observed at M0 in 4 patients. At M12, the proportion of patients with a VL <50 copies/ml reached 88% using an on-treatment analysis and 67% with an intent-to-treat analysis. The median increase in CD4+ T cells at M12 was 94 cells/μl. Four patients had a VF on therapy: two with wild-type viruses, one with selection of M184V and thymidine analogue mutations (TAMs) on a background of TAMs, and one with selection of K65R and M184V, with a replication capacity at 2.4%.

Conclusion

The virological response in our study demonstrates the antiviral efficacy of the AZT/3TC/TDF combination therapy, which needs further evaluation. The moderate frequency of selection of K65R could be due to the presence of AZT in the regimen.

A longitudinal and prospective study of Epstein-Barr virus load in AIDS-related non-Hodgkin lymphoma

BACKGROUND

Epstein-Barr virus (EBV) may be causally associated with non-Hodgkin Lymphoma (NHL) in HIV-infected patients.

OBJECTIVES

To compare EBV load in whole blood in AIDS-NHL patients, HIV non-AIDS patients and non-HIV-infected persons, and to prospectively measure EBV load in whole blood in AIDS-NHL patients.

STUDY DESIGN

Longitudinal and prospective study.

RESULTS

We observed no statistical difference in EBV load between AIDS-NHL (3.69log(10) copies/mL [interquartile range (IQR): 2.89-4.27]) and HIV non-AIDS patients (3.08log(10) copies/mL [IQR: 1.29-3.57]) but AIDS-NHL patients had significantly higher EBV loads than HIV-negative controls (1.19log(10) copies/mL [IQR: 0.00-3.29]). We noticed an inverse correlation between CD4+ lymphocytes count and EBV load in patients with AIDS-NHL (r(2)=0.41, P=0.01). In the longitudinal study, the mean EBV load three months after NHL diagnosis decreased significantly (mean difference=-1.69log(10) copies/mL [95% confidence interval: -0.32; -3.04]; P=0.03) under chemotherapy but was still elevated in patients with relapses or no response to chemotherapy.

CONCLUSION

Although EBV load seems a suboptimal marker for the diagnosis of AIDS-NHL, we observed a significant decrease of EBV load in patients treated with chemotherapy and a strong association between NHL outcome and EBV load in whole blood.

Reduced CD4 T cell activation and in vitro susceptibility to HIV-1 infection in exposed uninfected Central Africans

BACKGROUND

Environmentally driven immune activation was suggested to contribute to high rates of HIV-1 infection in Africa. We report here a study of immune activation markers and susceptibility to HIV-1 infection in vitro of forty-five highly exposed uninfected partners (EUs) of HIV-1 infected individuals in Central African Republic, in comparison with forty-four low-risk blood donors (UCs).

RESULTS

Analysis of T lymphocyte subsets and activation markers in whole blood showed that the absolute values and the percentage of HLA-DR+CD4 T cells and of CCR5+CD4 T cells were lower in the EUs than in the UCs (p = 0.0001). Mutations in the CCR5 coding region were not found in either group. Susceptibility to in vitro infection of unstimulated peripheral blood mononuclear cells, prior of PHA activation, was decreased in EUs compared to UCs, either using a CXCR4-tropic or a CCR5-tropic HIV-1 strain (p = 0.02 and p = 0.05, respectively). Levels of MIP-1beta, but not of MIP-1alpha or RANTES, in the supernatants of PHA-activated PBMC, were higher in the EUs than in the UCs (p = 0.007).

CONCLUSION

We found low levels of CD4 T cell activation and reduced PBMC susceptibility to HIV-1 infection in Central African EUs, indicating that both may contribute to the resistance to HIV-1 infection.

Virological response to HIV-1 nucleoside/nucleotide reverse transcriptase inhibitors-based, tenofovir DF-including regimens in the ANRS Aquitaine Cohort

BACKGROUND

HIV-1 nucleoside/tide reverse transcriptase inhibitors (NRTI)-only based, comprising tenofovir DF(TDF) have been shown to lead to high rates of virological failures (VF), mainly in patients on first-line combination therapy. We wished to investigate the virological response to these regimens in a large cohort of antiretroviral (ARV)-treated patients.

METHODS

Patients followed-up in the Aquitaine Cohort in 2001-2003 and who had received NRTI-based, TDF-including regimens for at least 3 months were included. The VF was defined as: (i) a decrease in plasma HIV-1 RNA <0.5 log(10)copies/ml between M0 and M3; or (ii) a plasma HIV-1 RNA >50 copies/ml at M3 in patients with plasma HIV-1 RNA <50 copies/ml at M0. The baseline RT genotype was determined in a subgroup of patients.

RESULTS

Within 121 patients (95% ARV-experienced) who received either lamivudine (3TC)/didanosine (DDI)/TDF (n=48), or abacavir (ABC)/3TC/TDF (n=14), or 3TC/zidovudine (ZDV)/TDF (n=27), or 3TC/ZDV/ABC/TDF (n=20), or DDI/ABC/TDF (n=12), the ABC/3TC/TDF and DDI/ABC/TDF combinations were associated with the highest frequencies of VF. In contrast the use of ZDV was related to a better virological response. The baseline RT genotype was also predictive of the virological outcome.

CONCLUSION

NRTI-based, TDF-including therapies can lead to high rates of VF both in ARV-naïve and in ARV-experienced patients. Our data strongly suggest the interest of associating ZDV and TDF in these regimens.

Virological Responses to Atazanavir–Ritonavir-Based Regimens: Resistance-Substitutions Score and Pharmacokinetic Parameters (Reyaphar Study)

Objective

To assess the impact of baseline HIV-1 substitutions, individual pharmacokinetic (PK) parameters (Cmin, Cmax, area under the curve [AUC0→24 h]) and genotype-inhibitory quotient (GIQ) on virological responses (VR) to atazanavir-ritonavir (300 mg/100 mg)-based highly active antiretroviral therapy (HAART) in 71 antiretroviral-experienced, atazanavir-naive patients in virological failure (VF) on HAART.

Methodology

VR was defined as HIV RNA <1.7 log10 copies/ml at week 12 (W12). A clinically relevant genotype-substitutions score for atazanavir-ritonavir was developed and validated (Reyaphar substitutions score). Previously published substitutions scores were also tested.

Results

Patients had a median (Q1; Q3) of 6 (3; 8) previous treatment lines during 9 (7; 11) years. Baseline (W0) values were as follows: 262 (187; 435) CD4+/μl, 3.9 (2.6; 4.9) log10 HIV-1 RNA copies/ml, 4 (2; 6) protease substitutions and 3 (1; 4) NRTI-related substitutions. Respective steady-state Cmin, Cmax and AUC0→24h were 300 (200; 700) ng/ml, 620 (430; 750) ng/ml and 78,000 (61,000; 94,000) ng.h/ml. At W12, 49% of the patients had VR with a median decrease of -1.2 (-0.5; -2.3) log10 HIV-1 RNA copies/ml. The Reyaphar score included 12 baseline protease substitutions from the International AIDS Society USA list that were associated with poorer VR: L10I/F/R/V, K20I/M/R, L24I, M46I/L, I54L/M/T/V, L63P, A71I/L/V/T, G73A/C/F/T, V77I, V82A/F/S/T, I84V, L90M and the polymorphism substitution Q58E. Comparing <5 versus ≥5 Reyaphar substitutions, the W12-W0 HIV-1 RNA decrease was -1.4 (-0.7; -2.3) versus -0.5 (-1.2; +0.5) log10 copies/ml ( P=0.009) with VR in 63% versus 11% ( P<10–4), respectively. This score predicted VF at W12 with 46% sensitivity, compared to 33% and 28% for the ANRS 2004 and 2005 scores. PK parameters alone were not associated with VR, but GIQ was associated with virological outcome ( P=0.04). I50L, known to be correlated with atazanavir-specific resistance, emerged in 2 (8%) of the 24 failing patients with paired genotypes at W0 and VF.

Conclusions

These findings highlight the need to cross-validate genotype-based algorithms to interpret substitution impact on virological outcome using different patient databases before their implementation in routine clinical practice.

Whole blood real-time quantitative PCR for cytomegalovirus infection follow-up in transplant recipients

BACKGROUND

Cytomegalovirus (CMV) remains a major opportunistic agent among transplant recipients. While detection of CMV pp65-lower matrix protein (pp65Ag) is still widely used for monitoring CMV infection, real-time PCR assays have been recently developed for routine quantitation of CMV DNA. However, correlations are lacking between results of pp65Ag and quantitative PCR assays and there is no consensus yet as to the more appropriate blood compartment (whole blood (WB), leukocytes, plasma) to be tested with PCR assays.

OBJECTIVES

The aims of the study were to determine, in a population of transplant recipients: (i) the correlation between pp65Ag and CMV quantitative real-time PCR in our setting and (ii) the utility of plasma CMV DNA quantitation in comparison to WB quantitation.

METHODS

In 170 blood samples (from 61 solid organ or bone marrow transplant recipients) with pp65Ag results, CMV quantitation was performed in WB and plasma using an in-house real-time quantitative PCR.

RESULTS

Real-time PCR and pp65Ag results in WB were correlated: thresholds of 10 and 50(+) cells/200,000 cells were equivalent to 3.3 log(10)copies/mL (2,000 copies/mL) and 3.8 log(10)copies/mL (6,300 copies/mL), respectively. When WB viral load was >or=3.6 log(10)copies/mL, the risk to have a negative plasma CMV DNA result was <or=2.5%.

CONCLUSIONS

For the routine exploration of a single compartment, whole blood would represent a suitable compromise: easy processing for a sensitive assay. The 3.6 log(10)copies/mL threshold, which could help in identifying active CMV infection, deserves further evaluation.

An additive/subtractive genotypic score as a determinant of the virological response to didanosine in HIV-1 infected patients

OBJECTIVE

To assess the genotypic determinants of the virological response (VR) to didanosine (ddI) in nucleoside reverse transcriptase inhibitors (NRTI)-experienced patients.

METHODS

Human immunodeficiency virus type 1 (HIV-1) genotype was determined at baseline in 74 ddI-naive-patients with baseline viral load >500 copies/ml and receiving ddI as part of a new regimen. VR was defined as a plasma HIV-1 RNA <50 copies/ml after three months on ddI. NRTI resistance mutations associated with higher or lower frequencies of VR with a p-value<0.25 were retained in different sets of mutations, where the mutations associated with a worse VR were added, whereas the mutations associated with a better VR were subtracted. The most significant mutation scores were then studied in a multivariate analysis.

RESULTS

Changes at three codons (M41L, L210W, T215Y/F/D/C/E) were associated with a worse VR and three mutations (K70R, M184V, K219Q) with a better VR. The strongest association with the VR was obtained with the score M41L+L210W+T215Y/F/D/C/E-K70R-K219Q. The score was independently associated with the VR in the multivariate analysis.

CONCLUSION

Taking into account the mutations associated with a better VR may improve genotypic resistance algorithms. Our results are of interest for the management of antiretroviral therapy in NRTI-experienced patients.

Evolution of Transmitted HIV-1 with Drug-Resistance Mutations in the Absence of Therapy: Effects on Cd4+ T-Cell Count and HIV-1 Rna Load

Sequence analysis of HIV-1 from 440 therapy-naive individuals included within the CASCADE study, who seroconverted within 18 months of the last negative test, identified 65 persons infected with a strain carrying resistance-associated mutations. Population-based sequencing was performed for 20 of these individuals during the therapy-free follow-up period. The median time of follow-up was 15 months (interquartile range from 10 to 23 months). Of these individuals, 12 showed subsequent evolution at the resistance positions, whereas the virus of 8 people was stable during this period. In the reverse transcriptase (RT) gene, the drug-resistant 215Y or 215F codons evolved to alternative codons in all six cases, 70R reverted to the wild-type 70K in 3 of the 4 individuals, 67N evolved only in 1 of 4 patients to a wild-type 67D, 215S evolved to wild-type 215T in 1 of 3 patients, 219N evolved to 219K in 1 of 2 patients, and one patient with 184V reversed to the wild-type 184M. The 181C variant evolved to the wild-type 181Y in 1 of 2 individuals. These codon changes were caused by single nucleotide mutations. No evolution was observed for other RT mutations: 41L, 69D, 69N, 190S, 210W, 215L, 215C, 215E and 219Q. In the protease gene, resistance mutations 84V and 90M were stable in 2 individuals. Comparing the CD4+ T-cell count of the 12 evolving versus the 8 stable cases revealed no statistically significant difference at the date of the first sequence following seroconversion. Interestingly, a lower CD4+ T-cell count was observed in the group without evolution at the second sequence time point ( P=0.043). No difference in HIV-1 RNA load was observed. These results, together with the apparent pressure to mutate at the resistance-associated positions exemplify the decreased fitness of viruses carrying 215Y/F, 70R or 184V

Prevalence of transmitted HIV-1 drug resistance and the role of resistance algorithms: data from seroconverters in the CASCADE collaboration from 1987 to 2003

OBJECTIVES

To examine factors influencing the rate of transmitted drug resistance (TDR) among seroconverters, with particular emphasis on 3 widely used genotypic drug resistance algorithms.

METHODS

The study used data from CASCADE (Concerted Action on Seroconversion to AIDS and Death in Europe), a collaboration of seroconverter cohorts in Europe and Canada. Genotypic resistance data were derived within 18 months of the last seronegative test or date of laboratory evidence of acute infection and before the initiation of antiretroviral therapy. The Stanford algorithm was used to analyze each individual's nucleotide sequence. A multivariate logistic model was used to assess independent relationships between the presence of TDR and exposure category, sex, age at seroconversion, and year of seroconversion. The paper also describes 3 alternative definitions of resistance: the Stanford algorithm, the key resistance mutations defined by the International AIDS Society, and the Agence Nationale de Recherches sur le Sida (ANRS) algorithm.

RESULTS

Forty-five of 438 patients (10.3%) seroconverting between 1987 and 2003 were infected with a drug-resistant HIV-1 variant. Forty patients (9.1%) showed resistance mutations to only 1 class of antiretroviral drugs, 2 (0.5%) to 2 classes, and 3 (0.7%) to 3 classes of antiretroviral therapy. It was suggested that individuals seroconverting later in calendar time were more likely to have TDR (relative risk 3.89 and 95% CI: 0.84 to 18.02, and relative risk 4.69 and 95% CI: 1.03 to 21.31, for 1996-1999 and 2000-2003, respectively, compared with pre-1996; P trend = 0.08). This trend was apparent regardless of the definition of TDR used. The total estimated proportion of individuals with TDR varied between 10.3% and 15.5% according to which definition was used.

CONCLUSIONS

Evidence was found for the rise of TDR over time. A specific definition of what constitutes TDR rather than a simple list of mutations is needed.

Antiretroviral efficacy and virological profile of a zidovudine/lamivudine/tenofovir disoproxil fumarate combination therapy in antiretroviral-naive patients

OBJECTIVE

To study the antiviral efficacy and the mutations selected by a triple therapy with zidovudine (AZT), lamivudine (3TC) and tenofovir disoproxil fumarate (TDF).

METHODS

Antiretroviral-naive patients received 300 mg AZT/150 mg 3TC twice a day plus 300 mg TDF once a day in an open pilot study. Follow-up was assessed at baseline therapy (MO) and at months 1, 3, 6, 9 and 12. Reverse transcriptase (RT) genotypic resistance analysis and in selected cases, a recombinant drug susceptibility and replication capacity assay were performed from plasma RNA at baseline and in case of virological failure (VF); that is, rebound of viral load >50 copies/microl on therapy.

RESULTS

Twenty-four patients were included. At baseline, the median CD4+ T-cell count was 443 cells/microl and the median plasma viral load (VL) was 4.38 log10 copies/ml. RT resistance mutations were observed at MO in 4 patients. At M12, the proportion of patients with a VL <50 copies/ml reached 88% using an on-treatment analysis and 67% with an intent-to-treat analysis. The median increase in CD4+ T cells at M12 was 94 cells/microl. Four patients had a VF on therapy: two with wild-type viruses, one with selection of M184V and thymidine analogue mutations (TAMs) on a background of TAMs, and one with selection of K65R and M184V, with a replication capacity at 2.4%/o.

CONCLUSION

The virological response in our study demonstrates the antiviral efficacy of the AZT/3TC/TDF combination therapy, which needs further evaluation. The moderate frequency of selection of K65R could be due to the presence of AZT in the regimen.