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Biomedical subjects

V Calvez

Publications and source records attributed to V Calvez.

At least 37 records · Page 2Linked to original sources
PubMed2001

MIKADO: a multicentre, open-label pilot study to evaluate the antiretroviral activity and safety of saquinavir with stavudine and zalcitabine.

BACKGROUND: Since eradication of HIV is unlikely, long-term management of the disease necessitates careful evaluation of the combinations of currently available drugs to determine the most potent and useful rational sequencing of regimens. OBJECTIVE: To determine the antiretroviral efficacy and tolerability of saquinavir soft gelatin capsule (SQV-SGC) plus zalcitabine (ddC) and stavudine (d4T), as first-line treatment in HIV-infected patients. DESIGN: Multicentre, open-label, non-comparative study. PATIENTS AND METHODS: Thirty-five asymptomatic, HIV-infected adults with no prior antiretroviral treatment, a CD4 count > or =250 cells/microL and baseline > or = 5000 HIV RNA copies/mL were included in the study. Patients received SQV-SGC 1200 mg three times a day (tid), ddC 0.75 mg tid and d4T 30 or 40 mg twice a day (bid) for 24 weeks. Plasma HIV RNA, CD4 and CD8 cell counts, HIV reverse transcriptase and protease resistance genotypes, SQV plasma concentration and tolerability were evaluated. RESULTS: At baseline, median HIV RNA (interquartile range) was 4.99 (4.81-5.48) log10 copies/mL, and median CD4 count was 370 (318-504) cells/microL (n = 35). At week 24, the median decrease in HIV RNA was 3.05 (2.19-3.68) log10 copies/mL. A viral load below the level of quantification (200 copies/mL and 20 copies/mL) was achieved in 63% and 34% of patients, respectively (intent-to-treat analysis). The only mutations detected were L90M substitutions in two patients. At week 24, the median CD4 count increased (P < 0.0001), and CD8 cell counts decreased (P < 0.0001), relative to baseline. In total, there were five cases of peripheral neuropathy (14%). Mean triglyceride and cholesterol levels remained within normal ranges. CONCLUSIONS: Triple therapy with SQV-SGC plus ddC and d4T is a reasonably well tolerated regimen that markedly and rapidly reduces viral load with immunological improvement. This combination is an effective additional therapeutic option, with an efficacy that compares favourably to other triple regimens used in HIV treatment.

Adult↗
PubMed2001

Prevalence and conditions of selection of E44D/A and V118I human immunodeficiency virus type 1 reverse transcriptase mutations in clinical practice.

Recently, it has been shown that a new mutational pattern (the E44D/A and/or V118I mutation) confers moderate phenotypic lamivudine resistance in the absence of the M184V mutation. The E44D/A and/or the V118I mutation does not exist in drug-naive patients, and the prevalence increases with the number of treatment regimens and lamivudine experience. The mutations can preexist in nucleoside-experienced but lamivudine-naive patients. They are always associated with zidovudine resistance-associated mutations, even in the absence of M184V. These mutations are more stable than the M184V substitution during antiretroviral treatment interruptions.

Alanine↗
PubMed2001

Genotypic and phenotypic resistance patterns of human immunodeficiency virus type 1 variants with insertions or deletions in the reverse transcriptase (RT): multicenter study of patients treated with RT inhibitors.

Genomic rearrangements in the 5' part of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) have been involved in multidrug resistance to nucleoside RT inhibitors (NRTI). We carried out a retrospective, multicenter study to investigate the prevalence, variability, and phenotypic consequences of such rearrangements. Data concerning the HIV-1 RT genotype and the biological and clinical characteristics of NRTI-treated patients were collected from 10 virology laboratories. Sensitivities of the different HIV-1 variants to RT inhibitors were analyzed in a single-cycle recombinant virus assay. Fifty-two of 2,152 (2.4%) RT sequences had a rearrangement in the 5' part of the RT, with an extensive molecular variation. The number of codons inserted between positions 68 and 69 ranged from 1 (3 samples) or 2 (41 samples) to 5 and 11 in one case each. In four cases, codon 67 was deleted. High levels of phenotypic resistance to zidovudine (AZT), lamivudine (3TC), stavudine (d4T), abacavir (ABC), and didanosine (ddI) were found in 95, 92, 72, 62, and 15% of the 40 samples analyzed, respectively. Resistance to AZT, d4T, and ABC could be found in the absence of the T215Y/F mutations. Resistance to 3TC could develop in the absence of specific mutations. Low-level resistance to ddI was noticed in 40% of the patients. The deletions of codon 67 seemed to have little effect on NRTI sensitivity. Most of the rearrangements were shown to contribute to cross-resistance to NRTI. The results regarding susceptibility to ddI raise the question of the interpretation of the phenotypic data concerning this drug.

Drug Resistance, Microbial↗
PubMed2001

Transient mobilization of human immunodeficiency virus (HIV)-specific CD4 T-helper cells fails to control virus rebounds during intermittent antiretroviral therapy in chronic HIV type 1 infection.

Immune control of human immunodeficiency virus (HIV) is not restored by highly active antiretroviral therapies (HAART) during chronic infection. We examined the capacity of repeated structured therapeutic interruptions (STI) to restore HIV-specific CD4 and CD8 T-cell responses that controlled virus production. Eleven STI (median duration, 7 days; ranges, 4 to 24 days) were performed in three chronically HIV-infected patients with CD4 counts above 400/mm(3) and less than 200 HIV RNA copies/ml after 18 to 21 months of HAART; treatment resumed after 1 week or when virus became detectable. HIV-specific T-cell responses were analyzed by proliferation, gamma interferon (IFN-gamma) production, and enzyme-linked immunospot assays. Seven virus rebounds were observed (median, 4,712 HIV-1 RNA copies/ml) with a median of 7 days during which CD4 and CD8 counts did not significantly change. After treatment resumed, the viral load returned below 200 copies/ml within 3 weeks. Significant CD4 T-cell proliferation and IFN-gamma production against HIV p24 appeared simultaneously with or even before the virus rebounds in all patients. These CD4 responses lasted for less than 3 weeks and disappeared before therapeutic control of the virus had occurred. Increases in the numbers of HIV-specific CD8 T cells were delayed compared to changes in HIV-specific CD4 T-cell responses. No delay or increase in virus doubling time was observed after repeated STI. Iterative reexposure to HIV during short STI in chronically infected patients only transiently mobilized HIV-specific CD4 T1-helper cells, which might be rapidly altered by virus replication. Such kinetics might explain the failure at delaying subsequent virus rebounds and raises concerns about strategies based on STI to restore durable HIV-specific T-cell responses in chronic HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Efficacy of dideoxynucleosides against human foamy virus and relationship to its reverse transcriptase amino acid sequence and structure.

Human foamy virus (HFV), a retrovirus of simian origin which occasionally infects humans, is the basis of retroviral vectors in development for gene therapy. Clinical considerations of how to treat patients developing an uncontrolled infection by either HFV or HFV-based vectors need to be raised. We determined the susceptibility of the HFV to dideoxynucleosides and found that only zidovudine was equally efficient against the replication of human immunodeficiency virus type 1 (HIV-1) and HFV. By contrast, zalcitabine (ddC), lamivudine (3TC), stavudine (d4T), and didanosine (ddI) were 3-, 3-, 30-, and 46-fold less efficient against HFV than against HIV-1, respectively. Some amino acid residues known to be involved in HIV-1 resistance to ddC, 3TC, d4T, and ddI were found at homologous positions of HFV reverse transcriptase (RT). These critical amino acids are located at the same positions in the three-dimensional structure of HIV-1 and HFV RT, suggesting that both enzymes share common patterns of inhibition.

Antiviral Agents↗
PubMed2001

Resistance profile and cross-resistance of HIV-1 among patients failing a non-nucleoside reverse transcriptase inhibitor-containing regimen.

The objectives were to determine the resistance profile and the rate of cross-resistance in HIV-1 infected patients failing an efavirenz or a nevirapine or a nevirapine then efavirenz containing regimens, and to investigate if zidovudine and more generally thymidine analog nucleosides lead to a particular genotypic pattern in nevirapine failing patients. A study was conducted in 104 patients with virological rebound to a non-nucleoside reverse transcriptase inhibitors (NNRTI) regimen (efavirenz n = 39, nevirapine n = 46 and nevirapine then efavirenz n = 19). Genotypic resistance testing was carried out of detectable plasma HIV-1 RNA (> 200 copies/ml). Among the 104 patients studied, only two patients failed to respond to the nevirapine regimen without selection of a NNRTI resistance mutation. All patients failing an efavirenz regimen harboured mutations conferring cross-resistance to nevirapine (K103N, Y188L, G190S). Among patients failing the nevirapine regimen and presenting with NNRTI mutations, 35 (80%) harboured mutations conferring cross-resistance to efavirenz (K101E, K103N, Y188L) and 9 (20%) harboured mutations conferring resistance to nevirapine alone (V106A and Y181C). In patients failing nevirapine then efavirenz therapy, all NNRTI resistance profile led to cross-resistance to all available NNRTIs. Among patients receiving nevirapine, the selection of mutations associated with a cross-resistance to efavirenz was more frequent statistically when a thymidine nucleoside analog (zidovudine or stavudine) was used in the regimen (P = 0.02). In conclusion, 100% of patients developed cross-resistance to nevirapine and efavirenz after treatment by efavirenz and 80% after treatment by nevirapine. The use of a thymidine analog concomitantly with nevirapine leads to the preferential selection of cross-resistance NNRTI mutations.

Alkynes↗
PubMed2001

Low-rate emergence of thymidine analogue mutations and multi-drug resistance mutations in the HIV-1 reverse transcriptase gene in therapy-naive patients receiving stavudine plus lamivudine combination therapy.

OBJECTIVES: Mutations usually associated with zidovudine exposure have been observed in zidovudine-naive patients treated by stavudine in combination. These mutations were named thymidine analogue mutations (TAMs). This fact, combined with phenotypical and biochemical findings provided additional evidence for cross-resistance between zidovudine and stavudine. A recent genotypic study in naive patients receiving stavudine/didanosine combination showed emergence of TAMs and a multidrug-resistance mutation (MDR), Q151M, in 36 and 10% of cases, respectively. Stavudine plus lamivudine is one of the most used binucleoside associations in the antiretroviral combinations. The objective of this study was to assess the genotypic changes in the HIV-1 reverse transcriptase (RT) gene in antiretroviral-naive patients treated by stavudine plus lamivudine. METHODS: We analysed the RT gene of 44 HIV-1 patients, naive of antiretroviral therapy, who were treated for 24 or 48 weeks with stavudine/lamivudine. RESULTS: At the end of the follow-up, all patients acquired the lamivudine-associated mutation M184V. Only two subjects (4.5%) developed a TAM (T215Y; M41L), one subject developed a V75T/A mutation and one subject developed the particular MDR pattern F116Y, Q151M. CONCLUSIONS: Our study clearly demonstrated that naive subjects treated with stavudine/lamivudine for 24-48 weeks selected a low rate of TAMs and MDR Q151M. One hypothesis explaining these results could be the development of the M184V mutation.

Acquired Immunodeficiency Syndrome↗
PubMed2000

HIV RNA and HIV DNA in peripheral blood mononuclear cells are consistent markers for estimating viral load in patients undergoing long-term potent treatment.

The aim of this study was to evaluate residual viral replication by assessing the HIV load of circulating infected cells in patients given an effective antiprotease-containing treatment for 1 year. PBMC HIV RNA and HIV DNA was quantified by techniques standardized and evaluated by interlaboratory quality control testing. Viral markers identified in a multicenter study were validated in a cross-sectional study of 121 patients beginning treatment. A longitudinal study of 3 viral markers was carried out in 18 patients, each of whom had fewer than 200 copies of HIV RNA per milliliter of plasma after 12 months of treatment. The cross-sectional study showed that viral replication in PBMCs was correlated with the number of circulating infected cells (Spearman rank correlation; p = 0.0001, r = 0.35) and the concentration of virus particles in the plasma (Spearman; p = 0.0001, r = 0.54). The longitudinal study showed that the decrease in HIV RNA levels was smaller in PBMCs than in the plasma. The largest decrease in HIV DNA levels after 12 months of treatment was recorded in patients with low levels of intracellular replication (Spearman; p = 0.005, r = 0.69). PBMC HIV RNA and HIV DNA levels were very informative markers, complementary to plasma HIV RNA levels. They should be used in future trials evaluating the long-term efficacy of new associations of highly active antiretroviral treatments.

Anti-HIV Agents↗
PubMed2000

Dynamics of HIV-specific CD8+ T lymphocytes with changes in viral load.The RESTIM and COMET Study Groups.

The influence of HIV burden variations on the frequencies of Ag-specific CD8+ T cell responses was evaluated before and during highly active antiretroviral therapy by analyzing the number, diversity, and function of these cells. The frequencies of HLA-A2-restricted CD8+ PBL binding HLA-A2/HIV-epitope tetramers or producing IFN-gamma were below 1%. A panel of 16 CTL epitopes covering 15 HLA class I molecules in 14 patients allowed us to test 3.8 epitopes/patient and to detect 2.2 +/- 1.8 HIV epitope-specific CD8+ subsets per patient with a median frequency of 0.24% (0.11-4. 79%). During the first month of treatment, viral load rapidly decreased and frequencies of HIV-specific CD8 PBL tripled, eight new HIV specificities appeared of 11 undetectable at entry, while CMV-specific CD8+ PBL also appeared. With efficient HIV load control, all HIV specificities decayed involving a reduction of the CD8+CD27+CD11ahigh HIV-specific effector subset. Virus rebounds triggered by scheduled drug interruptions or transient therapeutic failures induced four patterns of epitope-specific CD8+ lymphocyte dynamics, i.e., peaks or disappearance of preexisting specificities, emergence of new specificities, or lack of changes. The HIV load rebounds mobilized both effector/memory HIV- and CMV-specific CD8+ lymphocytes. Therefore, frequencies of virus-specific CD8 T cells appear to be positively correlated to HIV production in most cases during highly active antiretroviral therapy, but an inverse correlation can also be observed with rapid virus changes that might involve redistribution, sequestration, or expansion of these Ag-specific CD8 T cells. Future strategies of therapeutic interruptions should take into account these various HIV-specific cell dynamics during HIV rebounds.

Amino Acid Sequence↗
PubMed2000

Outcome of kidney transplant recipients with previous human herpesvirus-8 infection.

BACKGROUND: The consequences of a prior human herpesvirus-8 (HHV-8) infection in kidney-transplant recipients are still partially unknown. The aim of this monocentric study was to determine the prevalence of HHV-8-seropositive patients at the time of transplantation and to identify the main clinical events of these HHV-8+ recipients. METHODS: From January 1, 1990 to December 31, 1996, antibodies to HHV-8 latent nuclear antigen were detected by indirect immunofluorescent method in serum samples collected just before kidney transplantation from 400 consecutive patients. Conventional double or triple immunosuppressive treatment was prescribed. For the group of HHV-8+ recipients, data including death rate, graft survival, and occurrence of Kaposi's sarcoma (KS) were retrospectively collected until December 31, 1998. Cofactors associated with KS were studied in univariate and multivariate analyses using a Cox model. RESULTS: Thirty-two patients (8%) had antibodies to HHV-8 in their sera at the time of transplantation. Among these 32, 3 years after transplantation, graft survival was 72%, and KS prevalence was 28% (KS incidence: 8.2/yr/100 HHV-8+ recipients). Multivariate analysis identified bacterial and/or Pneumocystis carinii infection (odds ratio: 8.6; P=0.019) and female gender (odds ratio: 5.34; P=0.047) as factors associated with KS. No KS was observed in patients without anti-HHV-8 antibodies at the time of transplantation. CONCLUSIONS: The low graft survival and the high prevalence of KS within the studied population of HHV-8+ transplant recipients are strong arguments for systematic screening of HHV-8 serologic features before transplantation, especially in patients of African origin. HHV-8+ transplant recipients should be closely monitored to severe infections.

Adult↗
PubMed2000

Transactivation of the metallothionein promoter in cisplatin-resistant cancer cells: a specific gene therapy strategy.

BACKGROUND: Cisplatin (cis-diamminedichloroplatinum) is one of the most active agents against a broad range of malignancies, including ovarian cancer. Cisplatin resistance appears to be associated with several molecular alterations, including overexpression of metallothionein, a metal-binding protein. In the present study, we attempted to take advantage of metallothionein overexpression to overcome cisplatin resistance. METHODS: Using a virus-free system (liposomes), we sought to express the suicide gene, thymidine kinase (TK), driven by the promoter of the human metallothionein IIa (hMTIIa) gene using the pMT-TK plasmid. We used cisplatin-resistant human ovarian carcinoma cells as a model. RESULTS: We first analyzed metallothionein expression using a ribonuclease protection assay. In comparison to parental cells, the cisplatin-resistant cells were found to have increased expression of metallothionein messenger RNA (mRNA). Metallothionein overexpression in these cells was not associated with an increased copy number of the hMTIIa gene or with different transfection efficiencies. Furthermore, we showed by reverse transcription-polymerase chain reaction analysis that transfection of the pMT-TK plasmid results in a 56-fold higher expression of thymidine kinase mRNA in cisplatin-resistant cells compared with parental cells, consistent with increased metallothionein promoter-mediated transactivation in the cisplatin-resistant cells. Transfection of resistant cells with pMT-TK or a control plasmid (pCD3-TK) resulted in a marked sensitization to ganciclovir, with a 50% cell growth-inhibitory concentration (IC(50)) of 20 microg/mL and 9 microg/mL, respectively. Transfections of the cisplatin-sensitive cells resulted in no sensitization to ganciclovir with pMT-TK (IC(50) 200 microg/mL) and a high sensitization with pCD3-TK (IC(50) = 6 microg/mL). CONCLUSION: These studies suggest that pMT-TK gene therapy may provide an alternative treatment for cisplatin-refractory ovarian tumors.

Cisplatin↗
PubMed2000

Mechanisms of virologic failure in previously untreated HIV-infected patients from a trial of induction-maintenance therapy. Trilège (Agence Nationale de Recherches sur le SIDA 072) Study Team).

CONTEXT: In the Trilège trial, following induction with a zidovudine, lamivudine, and indinavir regimen, human immunodeficiency virus (HIV) replication was less suppressed by 2-drug maintenance therapy than by triple-drug therapy. OBJECTIVE: To identify mechanisms of virologic failure in the 3 arms of the Trilège trial. DESIGN: Case-control study conducted from February to October 1998. SETTING: Three urban hospitals in Paris, France. PATIENTS: Fifty-eight case patients with virologic failure (HIV RNA rebound to >500 copies/mL in 2 consecutive samples) randomized to 3 therapy groups: triple drug (zidovudine, lamivudine, and indinavir), 8; zidovudine-lamivudine, 29; and zidovudine-indinavir, 21; the case patients were randomly matched with 58 control patients with sustained viral suppression. MAIN OUTCOME MEASURES: At virologic failure (S1 sample) and 6 weeks later (S2 sample), assessment of protease and reverse transcriptase gene mutations, plasma indinavir level, and degree of viral load rebound; pill count during induction and maintenance periods. RESULTS: Only 1 primary resistance mutation, M184V, was detected in S1 plasma samples from 4 of 6 patients in the triple-drug and in all 22 in the zidovudine-lamivudine therapy groups and in S2 plasma samples from 3 of 6 in the triple-drug and 20 of 21 in the zidovudine-lamivudine groups. Of controls, M184V was detected in 11 of 13 S1 plasma samples and in 10 of 11 S2 plasma samples. Indinavir levels were undetectable in all S1 samples but 2 in 7 triple-drug cases tested and in the expected range in 11 of 18 S1 and 5 of 12 S2 zidovudine-indinavir case plasma samples tested. Maintenance adherence rates were lower for cases vs controls for zidovudine (P = .05) and indinavir (P = .05). Low indinavir levels, lower adherence rates for zidovudine (P = .04) and lamivudine (P = .03), and rebound to near-baseline values suggested adherence as cause of early failure for 4 of 8 triple-drug cases. In the zidovudine-lamivudine arm, for which case and control adherence rates did not differ significantly (P = .96), most failures occurred late with low rebound, suggesting suboptimal drug potency. In the zidovudine-indinavir arm, virologic failures may be related to both mechanisms. CONCLUSIONS: During the maintenance phase early and late virologic failures appeared to be related more to problems of adherence and antiretroviral treatment potency, respectively, than to selection of resistant mutant viruses.

Anti-HIV Agents↗
PubMed2000

Clinical features and contribution of virological findings to the management of Kaposi sarcoma in organ-allograft recipients.

OBJECTIVES: To describe the clinical features of Kaposi sarcoma (KS) in organ-allograft recipients and to determine the contribution of human herpesvirus 8 (HHV-8) investigations to the management of KS. DESIGN, SETTING, AND PATIENTS: We examined 20 organ-allograft recipients with KS at Pitié-Salpêtrière Hospital, Paris, France, between November 1, 1991, and May 31, 1999. METHODS: We detected HHV-8 antibodies using an indirect immunofluorescence assay and the HHV-8 DNA genome using nonnested polymerase chain reaction with KS-associated herpesvirus 330(233) primers in peripheral blood mononuclear cells collected at transplantation and KS diagnosis. We detected the HHV-8 genome in involved and uninvolved tissue specimens and in 10 patients' serum samples collected 1 month before the first manifestation of KS. We determined the HHV-8 double-strand DNA sequence and subtypes of open reading frame 26. INTERVENTION: Management of KS consisted of progressively tapering immunosuppressive therapy regardless of KS dissemination. Associated infections were treated when possible. Chemotherapy was prescribed only when a functional disability persisted, and polychemotherapy was prescribed for life-threatening disease. MAIN OUTCOME MEASURES: Percentage of recipients with KS remission and stabilization, organ-graft survival, and death rates. RESULTS: Remission of KS was obtained in 9 (45%) of the 20 patients independently of disease dissemination, with a mean follow-up of 35 months. The kidney graft survived in 12 (67%) of the 18 patients. Only 1 patient (5%) died of KS progression. All allograft recipients had anti-HHV-8 antibodies before transplantation. We detected HHV-8 DNA in all involved tissue samples but not in serum samples 1 month before KS onset. The most prevalent subtype was HHV-8 C (9 [53%] of 17 patients) and was not associated with extradermatological extension of KS compared with subtypes A and B'. CONCLUSIONS: Virological investigations of HHV-8 contribute poorly to KS management. Prospective studies are needed to determine the role of HHV-8 virological investigations and to identify associated cofactors so as to prevent KS in organ-allograft recipients.

Adult↗
PubMed2000

CD4+Ki67+ lymphocytes in HIV-infected patients are effector T cells accumulated in the G1 phase of the cell cycle.

Entry into the cell cycle represents a fundamental step before generating an effector immune response. The relationship between the cell cycle and antigen-driven T cell response remains, however, poorly understood in virus infection, including HIV. We have identified a critical fraction of CD4+CD45RO+ memory T lymphocytes that express the Ki67 antigen in chronically HIV-infected patients. A high accumulation of Ki67 protein is detected in CD4+CD45RO+Ki67+ cells that are in the G1 phase of the cell cycle (92 ¿ 5 %) but not in S and G2 + M phases, in contrast to normal individuals. Of these cells, 20 - 60 % are spontaneously producing IL-2 and IFN-, unlike CD4+CD45RO+ that do not express Ki67. In addition, HIV-p24 antigen is detectable only in a small fraction CD4+Ki67+ cells. In conclusion, CD4+Ki67+ lymphocytes are circulating effector cells accumulated in the G1 phase of the cell cycle and may be involved in the immune surveillance during HIV infection.

Antiretroviral Therapy, Highly Active↗
PubMed2000

Early virological failure in naive human immunodeficiency virus patients receiving saquinavir (soft gel capsule)-stavudine-zalcitabine (MIKADO trial) is not associated with mutations conferring viral resistance.

The MIKADO trial was designed to evaluate the efficacy of stavudine-zalcitabine-saquinavir (soft gel capsule) [d4T-ddC-SQV(SGC)] in 36 naive patients (-3.3 log(10) units at week 24 [W24]). Among the 29 patients remaining on d4T-ddC-SQV(SGC) until W24, 10 harbored a virological failure (viral load of >200 copies/ml at W24) (group 1). To determine the reasons for therapeutic failure, genotypic and phenotypic resistance test results and SQV concentrations in plasma were analyzed and compared to those in successfully treated patients (viral load of <200 copies/ml at W24) (group 2). Reverse transcriptase and protease genotypic analyses in group 1 revealed the acquisition of only one SQV-associated mutation (L90M) in only two patients. There was no significant increase in the 50 or 90% inhibitory concentration of SQV in patients with or without the L90M mutation. However, the fact that two patients developed an L90M mutation only 4 weeks after relapse points to the need for genotypic resistance testing in the context of an initial failure of the antiretroviral regimen. At W24, the median SQV concentration in group 1 (71 ng/ml) was significantly lower than in group 2 (475 ng/ml), and the plasma SQV concentration was correlated with the viral load at W24 (r = -0.5; P<0.05) and with the drop in viral load between day 0 and W24 (r = -0.5; P<0.01). These results and the fact that the plasma SQV concentrations in the two groups prior to relapse (W12) were not significantly different strongly suggest that the early failure of this combination is not due to viral resistance but to a lack of compliance, pharmacological variability, and drug interactions or a combination of these factors.

Anti-HIV Agents↗