BACKGROUND: Multiple resistance to nucleoside analogs mediated by the Q151M complex and/or codon 67-69 inserts/deletions represents a growing problem among HIV-infected persons, most of whom have been exposed to sequential therapies for long periods of time. PATIENTS AND METHOD: All plasma samples collected from HIV-infected patients failing antiretroviral therapy and referred for HIV genotyping to our institution during the last 3 years were examined. Genetic analysis of the reverse transcriptase (RT) and protease (PR) genes was performed using an automatic sequencer. RESULTS: Multinucleoside-resistance (MNR) genotypes were recognized in 22 (2.9%) of 761 participants. Twelve of them carried the Q151M complex and 9 harbored different codon 67-69 inserts. One participant carried a deletion at codon 67 of the RT gene. All patients with MNR viruses had been exposed to nucleoside analogs for a median of 54 months (range, 19-96). The mean plasma HIV RNA at the time MNR was first identified was 4.62 log and the mean CD4 count was 227 cells/microL. All patients with MNR viruses except two began salvage therapies based on protease inhibitors (PIs). Overall, 54.5% (12/22) of participants showed a significant virologic response (defined as >1 log reduction in plasma HIV RNA). Seven of them reached <50 copies/mL and remained with undetectable viremia for a median of 17 months (range, 8-50). No differences were found when patients with Q151M and codon 67-69 rearrangements were compared. The only predictor of response was the inclusion of ritonavir-boosted PI in the salvage regimen. In all patients with virologic failure, MNR genotypes have persisted over time. CONCLUSION: The prevalence of viruses with MNR genotypes is currently low (approximately 3%) among HIV-infected patients failing antiretroviral therapy. The expected poor prognosis of patients harboring MNR viruses may often be overcome using rescue interventions based on potent ritonavir-boosted PI combinations.
BACKGROUND: Multiple resistance to nucleoside analogs mediated by the Q151M complex and/or codon 67-69 inserts/deletions represents a growing problem among HIV-infectedpersons, most of whom have been exposed to sequential therapies for long periods of time. PATIENTS AND METHOD: All plasma samples collected from HIV-infectedpatients failing antiretroviral therapy and referred for HIV genotyping to our institution during the last 3 years were examined. Genetic analysis of the reverse transcriptase (RT) and protease (PR) genes was performed using an automatic sequencer. RESULTS:Multinucleoside-resistance (MNR) genotypes were recognized in 22 (2.9%) of 761 participants. Twelve of them carried the Q151M complex and 9 harbored different codon 67-69 inserts. One participant carried a deletion at codon 67 of the RT gene. All patients with MNR viruses had been exposed to nucleoside analogs for a median of 54 months (range, 19-96). The mean plasma HIV RNA at the time MNR was first identified was 4.62 log and the mean CD4 count was 227 cells/microL. All patients with MNR viruses except two began salvage therapies based on protease inhibitors (PIs). Overall, 54.5% (12/22) of participants showed a significant virologic response (defined as >1 log reduction in plasma HIV RNA). Seven of them reached <50 copies/mL and remained with undetectable viremia for a median of 17 months (range, 8-50). No differences were found when patients with Q151M and codon 67-69 rearrangements were compared. The only predictor of response was the inclusion of ritonavir-boosted PI in the salvage regimen. In all patients with virologic failure, MNR genotypes have persisted over time. CONCLUSION: The prevalence of viruses with MNR genotypes is currently low (approximately 3%) among HIV-infectedpatients failing antiretroviral therapy. The expected poor prognosis of patients harboring MNR viruses may often be overcome using rescue interventions based on potent ritonavir-boosted PI combinations.
Authors: Alexandra U Scherrer; Viktor von Wyl; Beda Joos; Thomas Klimkait; Philippe Bürgisser; Sabine Yerly; Jürg Böni; Bruno Ledergerber; Huldrych F Günthard Journal: J Infect Dis Date: 2011-02-01 Impact factor: 5.226
Authors: Jean L Mbisa; Ravi K Gupta; Desire Kabamba; Veronica Mulenga; Moxmalama Kalumbi; Chifumbe Chintu; Chris M Parry; Diana M Gibb; Sarah A Walker; Patricia A Cane; Deenan Pillay Journal: Retrovirology Date: 2011-05-11 Impact factor: 4.602