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At least 127 records · Page 7Linked to original sources
PubMed2004

Positive virological outcome after lopinavir/ritonavir salvage therapy in protease inhibitor-experienced HIV-1-infected children: a prospective cohort study.

BACKGROUND: Lopinavir/ritonavir has demonstrated antiviral activity in the HIV-infected patient. OBJECTIVE: To analyse virological response to lopinavir/ritonavir therapy in previously protease inhibitor (PI)-experienced HIV-1-infected children. MATERIALS AND METHODS: Sixty-seven HIV-1-children on lopinavir/ritonavir were studied in a multicentre prospective cohort observational study. The outcome variables were undetectable viral load (uVL; VL < or =400 copies/mL) and virological failure after uVL with a rebound of VL >400 copies/mL. VL and genotype of HIV-1-isolates were measured using standard assays. RESULTS: 83.5% of children had a 1 log10 VL decrease including 65.6% who reached uVL. Children with >2 changes of antiretroviral therapy (ART) or >5 drugs needed a median time of 3-4 months higher than children with < or =2 changes of ART or < or =5 drugs previous to lopinavir/ritonavir, to reach those values, and the relative proportions (RP) were 2.2 (P =0.038) and 1.9 (P=0.050), respectively. Children with CD4+>15% (P=0.122), VL < or =30,000 (P < 0.001) copies/mL, and age >12 years (P=0.096) achieved an earlier control of VL during the follow-up. The children with virological failure or rebound of VL had higher baseline VL and lower CD4+ T-lymphocytes/mm3 and had taken a greater number of drugs previous to lopinavir/ritonavir. HIV-children with a new nucleoside reverse transcriptase inhibitor (NRTI), or protease inhibitor (PI) or PI plus non-nucleoside reverse transcriptase inhibitors (NNRTI) in the current regimen had a better virological response than children without these new drugs. Also, children with <6 protease mutations had an RP of 2.31 of achieving uVL. CONCLUSIONS: Highly active antiretroviral therapy (HAART) including lopinavir/ritonavir induces beneficial effects in terms of virological outcome responses, and it is an effective option for salvage therapy in PI-experienced HIV-1-infected children.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Considerations in choosing a primary endpoint that measures durability of virological suppression in an antiretroviral trial.

OBJECTIVES: At present, many clinical trials of anti-HIV-1 therapies compare treatments by a primary endpoint that measures the durability of suppression of HIV-1 replication. Several durability endpoints are compared. DESIGN: Endpoints are compared by their implicit assumptions regarding surrogacy for clinical outcomes, sample size requirements, and accommodations for inter-patient differences in baseline plasma HIV-1-RNA levels and in initial treatment response. METHODS: Virological failure is defined by the non-suppression of virus levels at a prespecified follow-up time T(early virological failure), or by relapse. A binary virological failure endpoint is compared with three time-to-virological failure endpoints: time from (i) randomization that assigns early failures a failure time of T weeks; (ii) randomization that extends the early failure time T for slowly responding subjects; and (iii) virological response that assigns non-responders a failure time of 0 weeks. Endpoint differences are illustrated with Agouron's trial 511. RESULTS: In comparing high with low-dose nelfinavir (NFV) regimens in Agouron 511, the difference in Kaplan-Meier estimates of the proportion not failing by 24 weeks is 16.7% (P = 0.048), 6.5% (P = 0.29) and 22.9% (P = 0.0030) for endpoints (i), (ii) and (iii), respectively. The results differ because NFV suppresses virus more quickly at the higher dose, and the endpoints weigh this treatment difference differently. This illustrates that careful consideration needs to be given to choosing a primary endpoint that will detect treatment differences of interest. CONCLUSION: A time from randomization endpoint is usually recommended because of its advantages in flexibility and sample size, especially at interim analyses, and for its interpretation for patient management.

Anti-HIV Agents↗
PubMed2001

CCR5Delta32 and promoter polymorphisms are not correlated with initial virological or immunological treatment response.

OBJECTIVE: Natural genetic polymorphisms within the CCR5 gene and promoter have been linked to patterns of HIV-1 clinical disease progression in untreated individuals. The objective of this retrospective study was to assess the influence of the CCR5Delta32 mutation and promoter polymorphisms on virological and immunological treatment outcome in 436 antiretroviral-naive individuals initiating their first therapy, over a mean follow-up time of 22 months. METHODS: Genotypes for the CCR5Delta32 and promoter were determined by polymerase chain reaction amplification of human DNA from plasma, followed by gel electrophoresis for CCR5Delta32 or DNA sequencing for the promoter polymorphisms. Time to virological failure [defined as the second plasma viral load > or = 400 copies HIV-1 RNA/ml) and immunological failure (defined as time to achieve two successive CD4 cell counts below baseline) were analyzed by Kaplan-Meier methods. RESULTS: The five most common CCR5 promoter polymorphisms were observed at positions 208(G/T), 303(A/G), 627(C/T), 676(A/G), and 927(C/T). Allele frequencies were 0.24(208T), 0.38(303G), 0.44(627T), 0.35(676G) and 0.18(927T). The CCR5Delta32 allele frequency was 0.08. The promoter polymorphisms existed in strong linkage disequilibrium with each other and the Delta32. No significant effect of the individual CCR5Delta32 or promoter polymorphisms could be demonstrated with respect to time to treatment failure as defined by virological or immunological parameters (P > or = 0.07). Similarly, when combined CCR5Delta32 and promoter genotypes were analyzed in order to account for linkage disequilibrium, no significant effect was observed on time to virological or immunological failure (P > 0.6). CONCLUSION: CCR5Delta32 and promoter genotypes may not be of clinical relevance in predicting initial virological or immunological response to antiretroviral therapy.

Alleles↗
PubMed2002

Virologic response to nelfinavir-based regimens: pharmacokinetics and drug resistance mutations (VIRAPHAR study).

OBJECTIVE: To assess the impact of HIV-1 protease and reverse transcriptase (RT) mutations, and pharmacokinetic parameters on virological responses to nelfinavir (NFV)-containing highly active antiretroviral therapy. DESIGN: Naive or antiretroviral-experienced HIV-1-infected subjects were included in a non-randomized, observational cohort study and received two nucleoside RT inhibitors + NFV (750 mg three times per day or 1250 mg twice per day). Virologic success was defined as a virus load < 50 copies/ml for > 6 months. METHODS: RT and protease genes were sequenced at baseline and at the time of virological failure. Plasma NFV trough concentration (Cmin), maximum concentration (Cmax), and AUC0-tau at steady-state were subjected to population pharmacokinetic analysis. RESULTS: Patients (n = 154) enrolled between November 1998 and February 2000 started a twice per day (n = 84) or three times per day (n = 70) NFV-based regimen as first- (n = 48) or second-line therapy when protease inhibitor-naive (n = 64) or -experienced (n = 42). Median follow-up duration was 16 months. Virologic failure occurred in 88 patients. No significant differences were observed between twice per day and three times per day regimens. According to multivariate analysis, NFV Cmin and Cmax, CD4 cell count, number of baseline RT + protease gene mutations, D67N, M184V, T215F/Y in RT, and M36I in protease, were independent factors that were significantly predictive of failure. At failure, L10I, D30N, M36I, V77I, N88S/D or L90M protease mutations had emerged since baseline. Pharmacokinetic parameters were similar in patients with or without emergence of these neo-mutations. The more discriminating NFV Cmin efficacy-threshold was estimated to be 1 mg/l. CONCLUSIONS: Our data confirm the association among individual pharmacokinetic parameters, genotype pattern and virological response to NFV-containing regimens.

Adult↗
PubMed2004

Virological, intracellular and plasma pharmacological parameters predicting response to lopinavir/ritonavir (KALEPHAR study).

OBJECTIVES: To assess the impact of HIV-1 protease mutations and intracellular and plasma lopinavir minimum concentrations (Cmin) on virological success or failure on lopinavir/ritonavir-containing highly active antiretroviral therapy (HAART). DESIGN: HIV-1-infected HAART-experienced patients included in an observational study, received lopinavir/ritonavir (400/100 mg twice a day) plus two to three nucleoside reverse transcriptase inhibitors (NRTI) or one NRTI plus one non-NRTI. A viral load less than 50 copies/ml at month 6 defined virological success. METHODS: Intracellular and plasma lopinavir concentrations were determined by high-pressure liquid chromatography with mass-spectrometry detection. Reverse transcriptase and protease genes were sequenced at baseline and the time of virological failure. RESULTS: When the 38 patients started the lopinavir/ritonavir-based regimen, baseline median (25-75th percentile) values were: CD4 cell count 218 cells/microl (133-477); plasma HIV-1-RNA load 5.3 log10 copies/ml (3.8-5.1); number of lopinavir mutations four per protease gene (two to six). Univariate analysis associated virological success or failure at month 6 (21/38 patients) with the number of baseline lopinavir mutations, intracellular and plasma lopinavir Cmin, and the genotype inhibitory quotient (GIQ) at months 1 and 6. Multivariate analysis showed that the number of baseline lopinavir mutations and intracellular and plasma lopinavir Cmin were independently associated with virological success or failure. We defined the most discriminating intracellular and plasma lopinavir Cmin efficacy thresholds (8 and 4 microg/ml, respectively) and GIQ thresholds (1 and 3, respectively). CONCLUSION: The monitoring of lopinavir/rironavir-based HAART efficacy should include the number of baseline lopinavir/ritonavir mutations, intracellular and plasma lopinavir Cmin and GIQ calculation.

Adult↗
PubMed2005

Indinavir plasma concentration and adherence score are codeterminant of early virologic response in HIV-infected patients of the APROCO cohort.

To study the respective roles of indinavir concentrations and treatment adherence as predictors of early virologic response, we analyzed the patients of the APROCO cohort treated by indinavir 800 mg TID during the first 4 months. Minimum (Cmin), maximum (Cmax), and the ratio of the measured to expected concentrations (CR) were estimated for each patient at M4, from a population pharmacokinetic analysis of all data. The relationship among virologic success at M4 [plasma HIV RNA (VL) <500 copies/mL], baseline characteristics, estimated indinavir concentrations, and adherence score measured by a self-administered questionnaire, was analyzed by multivariate logistic regression. In the 216 studied patients, baseline median HIV RNA was 4.4 log10 copies/mL, and CD4 cell count was 309/mm. Virologic success was achieved in 195 (90%) patients; it was independently related to baseline viral load (OR = 0.524, CI 0.29-0.93; P = 0.03), antiretroviral treatment naive status (OR = 3.89, CI 1.29-11.76; P = 0.01), and indinavir Cmin (OR = 1.06, CI 1.02-1.10; P = 0.004) when adherence score was not included in the model, whereas full adherence was the only independent related factor when included in the model (OR = 8.8, 95% CI 2.85-27.3; P < 10). In the 168 fully adherent patients, virologic success was more frequent in patients with shorter duration of antiretrovirals at baseline (P = 0.03), lower baseline HIV RNA (P = 0.03), and higher indinavir CR (P < 10); the most discriminating Cmin cut-off was 194 ng/mL. Data on the relationship between indinavir plasma concentration and virologic success are therefore misleading without a concomitant assessment of adherence. These data suggest that any strategy of therapeutic drug monitoring must imply first a combined evaluation of plasma concentrations and adherence level and second an intervention target based on the results of both assessments.

Adult↗
PubMed2001

Genotypic correlates of a virologic response to stavudine after zidovudine monotherapy.

Prior evidence suggests that resistance to zidovudine (ZDV) confers some degree of cross-resistance to stavudine (d4T), but no genotypic correlates of clinical d4T susceptibility and resistance exist. To identify the genotypic correlates of a virologic response to d4T, reverse transcriptase (RT) sequencing of archived plasma HIV isolates was performed on 31 subjects who received d4T monotherapy in the AIDS Clinical Trials Group 302 study, all of whom received more than 3 years of ZDV monotherapy. Baseline characteristics and all RT mutations were analyzed for impact on virologic suppression. Eight of 31 subjects (27%) achieved a virologic response of greater than 0.3 log reduction in plasma HIV RNA after 8 weeks of d4T. Responders were more likely to have lower median baseline viral loads (4.2 vs. 4.7; p =.01) and a trend toward fewer ZDV-associated mutations (median: 1 vs. 2; p =.09). No subject with greater than one ZDV mutation had a virologic response to d4T. Seven of the 8 responders had only a K70R mutation at baseline. We conclude that in patients with prior ZDV treatment, those with only one ZDV mutation, particularly at position 70, can still get reasonable virologic activity from d4T. Those with more mutations are not likely to have much benefit.

Adult↗
PubMed2004

Use of viral load measured after 4 weeks of highly active antiretroviral therapy to predict virologic outcome at 24 weeks for HIV-1-positive individuals.

Early prediction of suboptimal viral response to highly active antiretroviral therapy (HAART) is vital to prevent early development of drug resistance. We used logistic regression to predict the odds of achieving virologic suppression (<50 copies/mL) after 24 weeks of HAART in 656 antiretroviral-naive patients starting HAART at the J.W. Goethe University, Chelsea and Westminster, and Royal Free Hospitals according to their week 4 viral load. Therapy changes involving the switch of a single antiretroviral were assumed to have occurred for toxicity reasons and ignored. Because complete regimen changes or additions of new antiretrovirals could be due to virologic failure, patients were counted as virological failures at week 24. Three hundred sixty (84%) of 430 patients with viral loads of <1000 copies/mL, 106 (61%) of 175 with viral loads between 1001 and 10,000 copies/mL, 11 (37%) of 30 with viral loads between 10,001 and 100,000 copies/mL, and 5 (24%) of 21 with viral loads of >100,000 copies/mL at week 4 subsequently attained virologic suppression at 24 weeks. The odds of attaining virologic suppression at 24 weeks was 65% lower for every 1-log higher viral load at week 4 (odds ratio, 0.35; 95% confidence interval, 0.27-0.45). The proportion of patients with an undetectable viral load at 24 weeks among those who have not attained a viral load of <1000 copies/mL by 4 weeks is quite low. We suggest that this group of patients should be particularly closely monitored.

Adult↗
PubMed2006

Regional changes over time in initial virologic response rates to combination antiretroviral therapy across Europe.

BACKGROUND: Changes in virologic response to initial combination antiretroviral therapy (cART) over calendar time may indicate improvements in cART or emergence of primary resistance. Regional variations may identify differences in available antiretroviral drugs or patient management. METHODS: Virologic response (viral load < 500 copies/mL) 6 to 12 months after starting cART was analyzed in antiretroviral-naive EuroSIDA patients. Analyses were stratified by region (south, central west, north, east) or time started cART (early, 1996-1997; mid, 1998-1999; late, 2000-1904). RESULTS: Virologic suppression was achieved by 60% of 2102 patients: 57% south (n = 560), 61% central west (n = 466), 63% north (n = 606), 58% east (n = 470) (P = 0.091). An increase was observed over time: 52% early cART, 56% mid cART, 69% late cART (P < 0.001). Overall, there were significant effects of region (P = 0.026) and time (P < 0.001) on virologic response after adjustment for confounders. Stratified by period, regional differences were less evident (early cART, P = 0.967; mid cART, P = 0.291; late cART, P = 0.163). Stratified by region, temporal changes were observed (south, P = 0.061; central west, P < 0.001; north: P = 0.070; east, P = 0.001). CONCLUSIONS: There was some evidence of regional differences in initial virologic response to cART. Improvements over time were observed, suggesting that so far, the effect of primary resistance has not been of sufficient magnitude to prevent increasing suppression rates.

Anti-HIV Agents↗
PubMed2005

Impact of liver steatosis on virological response in [corrected] Italian patients with chronic hepatitis C treated with peg-interferon alpha-2b plus ribavarin.

BACKGROUND: Whether liver steatosis affects sustained virological response in patients with chronic hepatitis C is still under discussion. AIM: To evaluate the impact of liver steatosis in patients treated (for chronic hepatitis C) with combination therapy. METHODS: We evaluated 97 (male/female 82/15, mean age 41.1 years) consecutive naive patients treated with pegylated interferon alpha-2b plus ribavirin. RESULTS: Prevalence and severity of liver steatosis were significantly associated with genotype 3a [grade 3-4 in 14 of 32 patients (44%) vs. 8 of 65 patients (12%) with other genotypes; P = 0.001], while steatosis grade 1 (<10% of hepatocytes affected) was more frequently associated with genotype 1a/1b [9/39 (23%) vs. 4/57 (7%); P = 0.02]. Overall, sustained virological response was 62.8%, and was statistically uninfluenced by the presence/absence of liver steatosis. On the contrary, the following variables were independently associated with sustained virological response at logistic regression analysis: genotype other than 1a/1b, positive association, (odds ratio 3.4, P < 0.04), and low-grade liver steatosis, negative association, (odds ratio 9.0, P = 0.009), whereas sustained virological response was unaffected by severe liver steatosis, which was mainly associated with genotypes 2 and 3 [steatosis grade 2, 18/29 (62%); grade 3, 10/12 (83%); grade 4, 7/10 (70%)]. CONCLUSIONS: Only low-grade liver steatosis negatively affects the outcome of combination therapy, with peginterferon alpha-2b plus ribavirin, while severe steatosis (which is virus-related in most cases) has no impact on virological response.

Adult↗
PubMed2006

Early virological response predicts outcome during extended lamivudine retreatment in patients with chronic hepatitis B who relapsed after initial HBeAg responses.

BACKGROUND AND AIM: Studies from hepatitis B virus endemic areas have shown less durable lamivudine-induced responses and have raised issues about the management of a post-treatment relapse. METHODS: From January 2000 to June 2004, all 51 patients (43 HBeAg-positive and eight HBeAg-negative) were retreated with lamivudine for at least 12 months. All had a post-treatment relapse after HBeAg responses (HBeAg loss/seroconversion) during the first therapy. RESULTS: During retreatment, HBeAg seroconversion occurred more frequently in those patients with HBeAg seroconversion than in those with HBeAg loss alone during prior lamivudine therapy (P = 0.001). On multivariate analysis, prior HBeAg seroconversion and early virological response (EVR) (< or = 2 months of retreatment) independently predicted HBeAg seroconversion (P = 0.012 and P = 0.004, respectively). With regard to virological breakthrough, only the time to virological response (> 2 months of retreatment) remained significant (P = 0.048). Among the HBeAg-negative patients, virological breakthrough occurred in only one patient with a late virological response. CONCLUSIONS: EVR is a major predictor in determining a favorable response to lamivudine retreatment. Our observations suggest that lamivudine retreatment will provide more therapeutic gains in those patients with a prior HBeAg seroconversion than in those with HBeAg loss alone.

Adult↗
PubMed2005

Virological and pharmacological parameters predicting the response to lopinavir-ritonavir in heavily protease inhibitor-experienced patients.

The genotypic inhibitory quotient (GIQ) has been proposed as a way to integrate drug exposure and genotypic resistance to protease inhibitors and can be useful to enhance the predictivity of virologic response for boosted protease inhibitors. The aim of this study was to evaluate the predictivity of the GIQ in 116 protease inhibitor-experienced patients treated with lopinavir-ritonavir. The overall decrease in human immunodeficiency virus type 1 (HIV-1) RNA from baseline to month 6 was a median of -1.50 log(10) copies/ml and 40% of patients had plasma HIV-1 RNA below 400 copies/ml at month 6. The overall median lopinavir study-state C(min) concentration was 5,856 ng/ml. Using univariate linear regression analyses, both lopinavir GIQ and the number of baseline lopinavir mutations were highly associated with virologic response through 6 months. In the multivariate analysis, only lopinavir GIQ, baseline HIV RNA, and the number of prior protease inhibitors were significantly associated with response. When the analysis was limited to patients with more highly mutant viruses (three or more lopinavir mutations), only lopinavir GIQ remained significantly associated with virologic response. This study suggests that GIQ could be a better predictor of the virologic response than virological (genotype) or pharmacological (minimal plasma concentration) approaches used separately, especially among patients with at least three protease inhibitor resistance mutations. Therapeutic drug monitoring for patients treated by lopinavir-ritonavir would likely be most useful in patients with substantially resistant viruses.

Adult↗
PubMedDate not supplied

Predictors of virological response to atazanavir in protease inhibitor-experienced patients.

BACKGROUND: Atazanavir (ATV) is the latest approved HIV protease inhibitor (PI). Even though it is very convenient (only two capsules once a day), concerns have risen about its potency. METHOD: The clinical performance of ATV 400 mg once a day was examined in all PI-experienced patients who were included in the ATV expanded access program conducted in a single institution. The predictive value of baseline drug resistance HIV genotypes, ATV plasma trough levels, and the genotypic inhibitory quotient (GIQ) on the virological response at week 24 was assessed. RESULTS: Data from 92 patients were analyzed. ATV was prescribed as part of a rescue intervention (45%), a simplification strategy (11%), or an attempt to ameliorate hyperlipidemias (23%) or other toxicities (16%). Tenofovir (TDF) was concomitantly used with ATV in 78% of patients. None received ritonavir boosting. In patients with detectable viremia at baseline (65%), the median HIV RNA drop was 0.7 logs. The median ATV Cmin was 0.12 microg/mL (IQR, 0.05-0.22 microg/mL), which is clearly above the IC90 (90% inhibitory concentration) for ATV in wild-type viruses. The virological response did not correlate significantly with ATV Cmin. The median number of protease resistance mutations was lower in patients showing virological response than in nonresponders (1 vs. 5; p=.07). A higher HIV RNA drop was associated with a higher GIQ (p=.02; beta=-5.4; 95% CI, -10 to -1). Only 4 patients (4%) discontinued treatment due to ATV-related toxicities (hyperbilirubinemia in 1). Bilirubin levels were associated with ATV plasma concentrations (p=.05; beta=3.2; 95% CI, -0.1 to 6.5). The rate of hypertriglyceridemia and hypercholesterolemia declined significantly with respect to baseline. CONCLUSION: ATV is relatively safe and provides significant virological response in PI-experienced patients, mainly among those with a low number of protease resistance mutations. The GIQ predicts accurately the virological response in patients receiving ATV. Hyperbilirubinemia is associated with higher ATV plasma levels.

Adult↗
PubMedDate not supplied

A cohort study of the food effect on virological failure and treatment discontinuation in patients on HAART containing didanosine enteric-coated capsules (FOODDIe Study).

BACKGROUND: Didanosine enteric-coated capsules (ddI-EC) should be taken under fasting conditions. However, the effect of food on the absorption of ddI-EC may not reduce exposure to the drug. METHOD: We performed an observational study to assess the effect on virological failure of taking ddI-EC with food. To be included, patients had to have begun their first ddI-EC-containing HAART regimen between June 1, 2001 and June 1, 2003. Primary endpoints were virological failure or discontinuation of the ddI-EC-containing regimen. RESULTS: 668 patients were included (119 patients were naïve, 172 switched from a different regimen, and 377 were part of rescue therapy). 296 patients were taking ddI-EC with food. After 71 weeks of follow-up, 162 discontinued ddI-EC in the fasting group and 120 in the fed group. 46 patients had virological failure (19 without food vs. 27 in the group with food). Adherence to therapy >80% was 79.7%. We fitted a multivariate Cox proportional hazard model and found a significant interaction between ddI-EC intake and adherence. The multivariate model showed that when adherence to HAART was poor (<80% of prescribed pills) taking ddI-EC with food significantly increased the risk of virological failure (hazard ratio [HR] 8.32, 95% CI 1.67-41.65), but this disappeared when adherence was 80%-95% (HR 0.27, 95% CI 0.04-1.53) or >95% (HR 0.57, 95% CI 0.12-2.77). CONCLUSION: When adherence is good (>80% of the prescribed doses), ddI-EC can be administered with food without an increase in virological failure or HAART discontinuation.

Administration, Oral↗
PubMedDate not supplied

Effect of prior nucleoside use on the two-year virological response to an initial protease inhibitor regimen in HIV-infected patients.

PURPOSE: This retrospective study investigates the effect of prior nucleoside (nucleoside reverse transcriptase inhibitor [NRTI]) experience on 2-year virologic response to an initial protease inhibitor-highly active antiretroviral therapy (PI-HAART) regimen. METHOD: 152 patients who started a PI (excluding saquinavir hard gel capsule [hgc] as a sole PI) with two NRTIs between January 1996 and May 1998 at two HIV treatment sites were included. RESULTS: 109 patients (71%) were NRTI experienced. 106 patients received two new NRTIs, and 32 received one new NRTI. Overall, 51% of patients had a virologic response (HIV viral load <400 copies/mL); the mean follow-up was 28 months. Virologic response was associated with the use of at least one new NRTI (relative risk [RR] 2.1; p =.031) but not with prior NRTI experience (p =.19). A complete virologic response was most likely to occur when two new NRTIs were used (RR 2.3) rather than one new NRTI (RR 1.8), but this was not significant (p =.12). CONCLUSION: This study suggests that prior nucleoside experience is not a key predictor of 2-year virologic response in patients who receive at least one new NRTI in an initial PI-HAART regimen.

Adult↗
PubMed2004

Methods for sentinel virological surveillance of influenza in Europe - an 18-country survey.

The European Influenza Surveillance Scheme (EISS) is based on an integrated clinical and virological surveillance model. To assess the comparability of virological data, a questionnaire was sent to participants in June 2002 enquiring about specimen collection, laboratory diagnosis of influenza and tests for other respiratory infections. The results showed differences, but also uniformity in virological data collection methods. Similarities were reported for the specimen collection procedures; the type of swab and the transport conditions were comparable. The diagnostic methods were diverse; differences were seen in the (sub)typing methods, with PCR used most often in western countries. The findings will be helpful for the interpretation of virological data collected by sentinel physicians and for the creation of a Community Network of Reference Laboratories for Human Influenza in Europe. Important objectives of the Community Network include the harmonisation of virological methods and the application of quality assurance assessments for the national reference laboratories.

Belgium↗
PubMed2006

Hepatitis C virus serologic and virologic tests and clinical diagnosis of HCV-related liver disease.

The use of serological and virological tests has become essential in the management of hepatitis C virus (HCV) infection in order to diagnose infection, guide treatment decisions and assess the virological response to antiviral therapy. Virological tools include serological assays for anti-HCV antibody detection and serological determination of the HCV genotype, and molecular assays that detect and quantify HCV RNA and determine the HCV genotype. Anti-HCV antibody testing and HCV RNA testing are used to diagnose acute and chronic hepatitis C. Only patients with detectable HCV RNA should be considered for pegylated interferon alfa and ribavirin therapy and the HCV genotype should be systematically determined before treatment, as it determines the indication, the duration of treatment, the dose of ribavirin and the virological monitoring procedure. HCV RNA monitoring during therapy is used to tailor treatment duration in HCV genotype 1 infection, and molecular assays are used to assess the end-of-treatment and, most importantly the sustained virological response, i.e. the endpoint of therapy.

Journal Article↗
PubMed2001

[Predictive factors of virologic response to antiretroviral treatment with a protease inhibitor in HIV infection].

OBJECTIVE: To investigate factors related to early virological response among a cohort of 224 patients who started a protease inhibitor (PI) for the first time. To determine which factors are associated with persistent response among patients with early response. PATIENTS AND METHODS: Early complete response was defined as an undetectable plasma viral load 2 to 3 months after treatment onset (< 400 copies/ml, Quantiplex HIV 2.0 Chiron diagnostics), incomplete response as at least 1 log reduction of viral load. In patients with an undetectable plasma viral load at 2 or 3 months, we also assessed the persistence of the response on the same regimen. Virology failure was defined by two consecutive viral load levels above the detection limit. RESULTS: In the total cohort, 66% of the patients had an early complete response, 11% a partial response and 23% no response. Complete virological response was significantly more frequent in naive (89%) than in pretreated (59%) patients (p < 0.001). Multivariate analysis of factors predictive of early response in pretreated patients (n = 169) showed that viral load (p = 0.001), the number of nucleoside analogs previously received (p = 0.06) and a full or partial treatment switch (p = 0.10) were associated with complete response. Analysis of later response in the 45 naive patients with prolonged follow-up showed that 22% had treatment failure after 3 to 16 months. None of the baseline variables (viral load, CD4+ cell count or nature of the PI) were associated with duration of response. The only factor associated with persistent response in pretreated patients was a low number of antiretroviral drugs previously received (log-rank test, p = 0.04). CONCLUSIONS: The absence of previous antiretroviral treatment as the main factor associated with an early complete virological response. In patients pretreated with nucleoside analogs who presented early virological success, the number of drugs previously received, often associated with full or partial switch of nucleoside analog, significantly influence the persistence of response to a given triple-drug regimen.

Adult↗