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C de Mendoza

Publications and source records attributed to C de Mendoza.

14 recordsLinked to original sources
PubMed2005

Multicenter evaluation of the NucliSens EasyQ HIV-1 v1.1 assay for the quantitative detection of HIV-1 RNA in plasma.

The Nuclisens EasyQ HIV-1 v1.1 assay (Biomerieux) is a real-time detection method combined with NASBA technology designed to measure plasma HIV-RNA. Its performance was assessed in 1008 clinical specimens collected from individuals infected with clade B (774) and non-B (234) HIV-1 variants at four European laboratories. The results were compared with those obtained using three other commercial viral load assays: Cobas Amplicor Monitor HIV-1 v1.5 (Roche), Versant HIV-1 RNA assay (Bayer) and Nuclisens HIV-1 QT (Biomerieux). Overall, the linearity, specificity and reproducibility of the EasyQ assay was comparable with that from the other tests. The correlation coefficient (R) between methodologies was 0.85 for Amplicor; 0.87 for Versant; and 0.91 for Nuclisens. The specificity of the assay was 99.4%. Of note, Versant missed 17% of specimens with non-B subtypes which could be detected by EasyQ, while Amplicor provided similar results than EasyQ. HIV-1 group O specimens were only detected by the EasyQ assay. In conclusion, the performance of the EasyQ assay seems to be similar to that of other HIV-1 viral load tests currently on the market, but it is more sensitive than Versant for HIV-1 non-B subtypes and shows a wider dynamic range than Amplicor. Moreover, as it incorporates the advantage of real-time detection procedures, it facilitates high throughput and short turnaround time.

France↗
PubMed2001

Drug resistance in patients experiencing early virological failure under a triple combination including indinavir.

OBJECTIVE: To assess the pattern of drug resistance mutations selected in HIV-1-infected patients failing a first line triple combination therapy including indinavir. PATIENTS AND METHODS: Plasma samples from 87 patients collected at the time of the first virological rebound (> 50 HIV-RNA copies/ml) were examined for the presence of drug-resistant genotypes. RESULTS: The mean level of plasma viraemia at rebound was 7824 HIV-1 RNA copies/ml in 73 subjects with good compliance, whereas it was 359,460 HIV-1 RNA copies/ml in 14 patients who admitted to poor adherence. Genetic sequence analysis yielded results for 51 (70%) of the patients having good adherence. More than half of them (26/51, 51%) carried primary mutations associated with resistance to nucleoside analogues. In contrast, primary protease inhibitor resistance mutations were recognized less frequently (14/51, 27%; P < 0.05). Moreover, in 23 (45%) patients there was no evidence of drug-resistant viruses at all. The most frequent drug-resistant genotypes in the reverse transcriptase gene were at codons 184 (n = 19), 215 (n = 14) and 41 (n = 8), whereas for the protease they were at codons 46 (n = 10), 82 (n = 9) and 90 (n = 7). No resistance genotypes were found among non-compliant patients. CONCLUSION: The overall rate of drug-resistant HIV genotypes was 38% (28/73) in patients with good adherence and who were experiencing a first virological failure under a triple combination regimen including indinavir; resistance to nucleoside analogues was more frequent than resistance to indinavir. Therefore, treatment intensification in those patients without resistance, or a selective substitution of nucleosides in those with resistance limited to these compounds, might be justified.

Adult↗
PubMed2001

Monitoring the response to antiretroviral therapy in HIV-1 group O infected patients using two new RT-PCR assays.

Failure to recognise infection caused by human immunodeficiency virus type 1 (HIV-1) group O variants has been described using both serological and genetic procedures. Moreover, monitoring the response to antiretroviral therapy is a difficult task in patients infected with HIV-1 group O since commercial tests are not available so far for the quantitation of this virus. In this study, the virological response to antiretroviral therapy were assessed in five HIV-1 group O-infected patients living in Spain by using two new and different RT-PCR methods (MUPROVAMA and LCx). Twenty-four plasma samples belonging to these five patients were selected. As reference, p24 antigenaemia levels and CD4+ cell counts were used. All samples yielded positive viral load values using MUPROVAMA (range: 138 to 595,500 HIV-RNA copies/ml) and 23 of 24 using LCx (range: < 178 to 98,356 HIV-RNA copies/ml). Overall, the results obtained using both assays showed a good correlation among themselves, and in respect to p24 antigenaemia and CD4+ cell counts. However, the values provided by LCx were significantly lower (0.33 logs on average) than those provided by MUPROVAMA. In conclusion, both the highly sensitive MUPROVAMA and LCx Quantitative assays might represent an useful tool for guiding the decision on when start treatment and for monitoring the response to antiretroviral therapy in HIV-1 group O-infected patients.

Adolescent↗
PubMed1999

Comparison of three different commercial methods for measuring plasma viraemia in patients infected with non-B HIV-1 subtypes.

In order to determine whether commercial assays presently in use for the quantification of plasma human immunodeficiency virus type 1 (HIV-1) RNA levels detect different genetic viral subtypes with the same reliability, a panel of 38 samples corresponding to 22 HIV-1-infected patients, representing non-B subtypes A-F, was examined. One to three plasma samples belonging to each individual were tested by the second-generation HIV-1 branched DNA (bDNA) assay (Chiron, Spain), the Nuclisens assay (Organon-Teknika, Spain), the Amplicor Monitor reverse transcriptase polymerase chain reaction assay (Roche, Spain), and the Ultradirect Monitor (Roche) using primers specifically designed to amplify non-B HIV-1 subtypes. Each of the different methods for measuring viral load showed a distinct sensitivity for non-B HIV-1 subtypes. Values higher than the assay detection limit were obtained in 22 (57.9%), 33 (86.8%), and 37 (93.3%) samples using the bDNA, Nuclisens, and Monitor assays, respectively. Significantly different values (>0.5 logs) were found in 55.3%, 81.6%, and 71.1% of specimens comparing results provided by bDNA and Nuclisens, bDNA and Monitor, and Nuclisens and Monitor, respectively. Quantitative values provided by the Ultradirect Monitor test using non-B primers were particularly discordant with the other tests. Overall, 44.7% of samples yielded higher viral load values with this assay than with the regular Monitor assay, reflecting its enhanced sensitivity for non-B subtypes; however, the reproducibility of this test was low. These results support the recommendation of always using the same assay when monitoring plasma viraemia.

HIV Infections↗
PubMedDate not supplied

Different outcomes in patients achieving complete or partial viral load suppression on antiretroviral therapy.

BACKGROUND: Potent combination antiretroviral therapy can reduce HIV plasma viral load (VL) to levels below the detection limit for as long as 2 years or more. A VL <500 HIV RNA copies/mL was until recently considered a reasonable therapeutic goal. However, lower levels seem necessary if VL rebounds and development of drug resistance are to be avoided. PATIENTS AND METHODS: The clinical and virologic outcome at 1 year were prospectively examined in a group of 100 patients who began a triple combination antiretroviral therapy regimen consisting of stavudine (d4T), lamivudine (3TC), and indinavir (IDV). A modified ultrasensitive VL test with a detection limit of 40 copies/mL and a point mutation nested polymerase chain reaction (PCR) assay for detecting the codon 184 mutation conferring 3TC resistance were used for testing samples collected longitudinally from these individuals. RESULTS: Overall, VL values <40 copies/mL were reached in 45% and 32% of patients at nadir and at 12 months, respectively. More than half (24 of 45 persons) who achieved a level <40 copies/mL at nadir remained with undetectable VL at 1 year, whereas this occurred in only one fourth (7 of 28 persons) of those having levels of 40 to 500 copies/mL (P < .05). However, rebounds in VL to >500 copies/mL at 1 year were seen at similar rates (26.6% and 25%, respectively) in persons achieving either complete (<40 copies/mL) or partial (40-500 copies/mL) VL suppression at nadir. In contrast, the codon 184 mutation emerged more frequently at 1 year in patients whose VL remained between 40 and 500 copies/mL at nadir than in those who reached a level <40 copies/mL (30.7% versus 0%; P < .05). CONCLUSION: Plasma VL at nadir after beginning highly active antiretroviral therapy (HAART) predicts the 1-year outcome. The achievement of levels of viremia <40 copies/mL are desirable during antiretroviral therapy if prolonged benefit is to be obtained. Because more than two thirds of persons with residual viremia do not show drug resistance, intensification strategies should be investigated for those patients with a good virologic response but without complete suppression during the first 6 months on HAART.

Adult↗
PubMedDate not supplied

Efficacy and safety of didanosine and lamivudine both once daily plus indinavir in human immunodeficiency virus-infected patients.

BACKGROUND: The combination of didanosine (DDI) and lamivudine (3TC) has been not recommended in guidelines for the first-line treatment of human immunodeficiency virus (HIV) infection because two major considerations might reduce its efficacy. First, both drugs are non-thymidine nucleosides and might exert less antiviral activity on activated T cells. Second, the codon 184 mutation emerging under 3TC failure could confer cross-resistance to DDI. However, because the intracellular half-life of their active metabolites allows administration once daily, the resulting improvement in patient compliance should favor this combination over others. PATIENTS AND METHODS: We analyzed the virologic and immunologic outcome at 6 months in 46 naive HIV-infected patients (41% were intravenous drug users) who began a treatment of a triple combination of DDI, 3TC, and indinavir (IDV) with the schedule optimized to improve adherence. Both DDI and 3TC were administered once daily (450 mg and 300 mg, respectively) and IDV was taken twice daily (1,200 mg). Patients chose schedules at their convenience, according to their job timings and preferences. All had a plasma viral load (PVL) of more than 500 HIV-RNA copies/mL at the time they entered the study, and overall the mean PVL value was 54,201 copies/mL. RESULTS: Overall, nine patients did not complete the study period: two died of non-acquired immunodeficiency syndrome (AIDS)-related causes, three described severe gastrointestinal symptoms, one discontinued therapy voluntarily, and three were lost to follow-up. Among the remaining 37 patients, a PVL value of less than 500 copies/mL was reached by 31 (83.7%) patients, and values below 40 copies/mL were recorded in 71% (22/31) of them. Overall, a clinically significant increase in the CD4 cell count (more than 60 cells/microL) was seen in 70.2% (26/37) of patients. Treatment adherence, assessed using both self-reporting and the pill count method, was considered good (more than 90% of pills prescribed were taken) in all but four patients; three of them were among those six who did not reach undetectable PVL values at the sixth month. Mutations at codons 184, 74, 65, and 151, which confer resistance to 3TC and DDI, could be examined in 12 of the 15 patients having PVL values above 40 copies/mL at the sixth month. The codon 184 mutation emerged in 25%, meanwhile the codon 74 mutation only appeared in one patient; none carried the codon 151 mutant genotype. Nine months after beginning treatment, 29 (93.5%) of the 31 patients who reached less than 500 copies/mL at the sixth month still sustained PVL values below this threshold, and 25 (80.6%) had less than 40 copies/mL. CONCLUSION: The combination of DDI and 3TC both once daily plus IDV twice daily is well tolerated, seems to favor a good adherence, and shows significant antiviral activity.

Anti-HIV Agents↗