Efficacy of first-line antiretroviral HIV-therapy guided by genotypic resistance testing and the geno2pheno® interpretation system

Poster number: 26

M Oette (1), R Kaiser (2), M Däumer (2), N Beerenwinkel (3), T Sing (3), J Buech (3), R Petch (1), D Hoffmann (4), J Selbig (5), T Lengauer (3), D Häussinger (1)

  1. University Clinic of Düsseldorf, Germany
  2. University of Cologne, Germany
  3. MPI for Informatics, Saarbrücken, Germany
  4. CAESAR Foundation, Bonn, Germany
  5. MPI for Molecular Plant Physiology, Golm, Germany

Background: Antiretroviral drug resistance in previously untreated HIV-infected patients is of growing relevance in the last years. Retrospective data have shown that first-line highly active antiretroviral therapy (HAART) in patients with resistant isolates is less likely to be effective. The aim of the study was to determine the efficacy of resistance-guided HAART in these patients.



Methods: In a prospective multicenter-study in Nordrhein-Westfalen, Germany, first-line HAART was guided by genotypic resistance testing using the geno2pheno bioinformatics analysis and virologists expert interpretation in untreated chronically infected HIV-positive patients.



Results: Between January 2001 and December 2004 resistance testing was performed in 585 therapy-naive individuals (mean age 38,4 y, 76,3 % males, 80,0 % caucasian, 42,8 % CDC C, mean CD4 cell-count 242/ml, mean viral load 196.799 copies/ml). HAART was initiated in 269 cases, 24-weeks-data were available for 269 patients, 48-weeks-data were available for 213 patients. Primary drug resistance was found in 12,3 %, predominantly resistance associated with nucleoside reverse transcriptase inhibitors (8,5 %). Treatment outcome is shown in the table.


































Percentage of patients with
viral load < 50 c/ml
Patients with
resistance (%)
Patients without
resistance (%)
p-value
24 weeks:
Intent-to-treat analysis
66,7 73,3 0,41
24 weeks:
On-treatment analysis
78,6 82,0 0,61
48 weeks:
Intent-to-treat analysis
66,7 74,2 0,49
48 weeks:
On-treatment analysis
81,8 86,3 0,52




Conclusion: In our study, prevalence of primary resistant virus strains was 12 % in chronically infected HAART-nave HIV-patients in Germany. Unlike previous data, first-line HAART was equally effective in patients with and without resistant virus. Thus, genotypic resistance testing should become routine practice before first-line HAART. The results support the good clinical efficacy of the geno2pheno interpretation system.