AIDSWEEKLY Plus; Monday, March 2, 2009
Staff Medical Writers

NewsRx -- According to recent research from the United States, "The efficacy of various antiretroviral (ARV) therapy regimens for human immunodeficiency virus type 2 (HIV-2) infection remains unclear. HIV-2 is intrinsically resistant to the nonnucleoside reverse-transcriptase inhibitors and to enfuvirtide and may also be less susceptible than HIV-1 to some protease inhibitors (PIs)."

"However, the mutations in HIV-2 that confer ARV resistance are not well characterized. Twenty-three patients were studied as part of an ongoing prospective longitudinal cohort study of ARV therapy for HIV-2 infection in Senegal. Patients were treated with nucleoside reverse-transcriptase inhibitor (NRTI)- and PI (indinavir)-based regimens. HIV-2 pol genes from these patients were genotyped, and themutations predictive of resistance in HIV-2 were assessed. Correlates of ARV resistance were analyzed. Multiclass drug-resistance mutations (NRTI and PI) were detected in strains in 30% of patients; 52% had evidence of resistance to at least 1 ARV class. The reverse-transcriptase mutations M184V and K65R, which confer high-level resistance to lamivudine and emtricitabine in HIV-2, were found in strains from 43% and 9% of patients, respectively. The Q151M mutation, which confers multinucleoside resistance in HIV-2, emerged in strains from 9% of patients. HIV-1 - associated thymidine analogue mutations (M41L, D67N, K70R, L210W, and T215Y/F) were not observed, with the exception of K70R, which was present together with K65R and Q151M in a strain from 1 patient. Eight patients had HIV-2 with PI mutations associated with indinavir resistance, including K7R, I54M, V62A, I82F, L90M, L99F; 4 patients had strains with multiple PI resistance - associated mutations. The duration of ARV therapy was positively associated with the development of drug resistance (P=0.02). Nine (82%) of 11 patients with HIV-2 with detectable ARV resistance had undetectable plasma HIV-2 RNA loads (<1.4 log₁₀ copies/mL), compared with 3 (25%) of 12 patients with HIV-2 with detectable ARV resistance (P=0.009). Patients with ARV-resistant virus had higher plasma HIV-2 RNA loads, compared with those with non-ARV-resistant virus (median, 1.7 log₁₀ copies/mL [range, <1.4 to 2.6 log₁₀ copies/mL] vs. <1.4 log₁₀ copies/mL [range, <1.4 to 1.6 log₁₀ copies/mL]; P=0.003). HIV-2-infected individuals treated with ARV therapy in Senegal commonly have HIV-2 mutations consistent with multiclass drug resistance," wrote G.S. Gottlieb and colleagues, University of Washington (see also HIV/AIDS).

The researchers concluded: "Additional clinical studies are required to improve the efficacy of primary and salvage treatment regimens for treating HIV-2 infection."

Gottlieb and colleagues published their study in Clinical Infectious Diseases (Emergence of Multiclass Drug-Resistance in HIV-2 in Antiretroviral-Treated Individuals in Senegal: Implications for HIV-2 Treatment in Resouce-Limited West Africa. Clinical Infectious Diseases, 2009;48(4):476-483).

For additional information, contact G.S. Gottlieb, University of Washington, Division Allergy & Infectious Disease, Dept. of Medical, Mailstop 358070, Seattle, WA 98195, USA.

Publisher contact information for the journal Clinical Infectious Diseases is: University Chicago Press, 1427 E 60th St., Chicago, IL 60637-2954, USA.

Keywords: United States, Seattle, HIV/AIDS, AIDS, Acquired Immune Deficiency Syndrome, Acquired Immunodeficiency Syndrome, Anti-Infectives, Antivirals, Clinical Trial Research, Drug Development, Drug Resistance, Drugs, Emtricitabine, Enfuvirtide, Enzyme Research, Enzymes, Enzymology, Fusion Inhibitor, Genotyping, HIV, Human Immunodeficiency Virus, Immunology, Indinavir, Lamivudine, Nucleoside Reverse Transcriptase Inhibitor, Pharmaceuticals, Protease Inhibitor, Protease Inhibitors, Proteins, Proteomics, Sexually Transmitted Disease, Therapy, Treatment, Viral, Virology, University of Washington.

This article was prepared by AIDS Weekly editors from staff and other reports.

2009-03-02
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