LB-24. HIV Drug Resistance Interpreted by Cumulative versus Last Genotypes in HIV-infected Patients with Multiple Treatment Failures
Session: Poster Abstract Session: Late Breaker Posters
Saturday, October 22, 2011
Room: Poster Hall B1
  • poster_IDSA_2011.pdf (30.5 kB)
  • Background: Genotypic resistance testing has been recommended to evaluate HIV drug resistance and guide the effective regimens of antiretroviral therapy (ART) in HIV-infected patients with treatment failure. In patients with multiple treatment failures, the mutations associated with resistance may disappear due to the loss of selective drug pressure after switching regimens. We aimed to determine the levels of HIV drug resistance between using cumulative and last genotypic resistance test results.

    Method: A retrospective cohort study was conducted among HIV-infected patients who followed up at a medical-school hospital and had at least two genotypic resistance tests between January 2003 and June 2011. All plasma samples, HIV-1 pol nucleotide sequencing of reverse transcriptase and protease region were carried out using TRUGENE HIV-1 Genotypic Assay. Drug resistance mutations were analyzed using Stanford rule based interpretation algorithms.

    Result: There were 54 patients with mean (SD) age of 30.1 (15.4) years and 46.3% were males. HIV-1 subtype A/E, B, and A were observed in 88.9%, 9.3%, and 1.9%, respectively. At latest failure, 55.3% were receiving protease inhibitor-based regimens; 40.4% using lopinavir/ritonavir. Median (IQR) CD4 and HIV RNA were 167 (80-351) cells/mm³ and 22,359 (6,329-118,345) copies/mL. During a median (IQR) duration of ART of 38.6 (24.6-55.3) months, 72.2%, 22.2%, and 5.6% had 5, 3, and 2 genotype tests, respectively. When compared between using cumulative (CG) and last (LG) genotypic resistance test results, CG interpreted the proportion of patients with any drug resistance 59.3% higher than LG did. For NRTI, NNRTI, and PI drug classes, CG interpreted as resistance 42.6%, 27.8%, and 7.4% higher than LG, respectively. The most common drugs that CG interpreted resistance with the higher rate than LG were lamivudine/emtricitabine (33.3%), nevirapine (24.1%), efavirenz (24.1%), etravirine (22.2%) and abacavir (20.4%).

    Conclusion: Among HIV-infected patients with multiple treatment failures, CG interprets HIV drug resistance at a higher rate than LG and may be more accurate to use for selecting the next effective regimen of ART in this population. 

    Subject Category: H. HIV/AIDS and other retroviruses

    Punthiya Punyacam, M.D.1, Nareenart Iemwimangsa, B.Sc.2, Wasun Chantratita, Ph.D.2, Chonlaphat Sukasem, Ph.D.2 and Somnuek Sungkanuparph, M.D.1, (1)Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand, (2)Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand


    P. Punyacam, None

    N. Iemwimangsa, None

    W. Chantratita, None

    C. Sukasem, None

    S. Sungkanuparph, None

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