Intensification of antiretroviral therapy

[Genotypic resistance of human immunodeficiency virus in patients with virologic failure]

BACKGROUND

The aim of the present study is to asses the prevalence of resistances in a group of patients with virological failure establishing the relationship between the appearance of mutations and the given antiretroviral therapy along with other variables used in these patients follow-up.

PATIENTS AND METHOD

Samples belonging to 88 patients were selected either with viral load levels above 30.000 copies/ml after reaching undetectable viral load levels, or with persistently detectable levels above 1.000 copies/ml. Resistances were tested by means of Line Probe Assay (LiPA). The history of patients' antiretroviral treatments was reviewed.

RESULTS

Mutations were observed in 52,6% of cases for reverse transcriptase (RT) an in 81,8% for the protease genes, being T215Y and V82A the most frequently detected ones. Mutations coferring resistance to the given antiretrovirals appeared in 33 cases. No statistical significance was observed between the presence of mutations and the administered therapy. In the multivariate analysis we found for LiPA RT a greater risk of appearance of mutations according to patient motility (OR = 4,0).

CONCLUSIONS

the prevalence of resistance mutations in patients with virologic failure is placed around 50% in both genes. A consensus in the definition of virologic failure in HIV infected patients is urged.

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.