Drug-resistance genotyping in HIV-1 therapy: the VIRADAPT randomised controlled trial.
BACKGROUND
Growing evidence has linked HIV-1 resistance mutations and drug failure. The use of genotypic-resistance analysis to assist therapeutic decision-making in patients failing therapy has not been investigated. We assessed the virological and immunological impact of genotypic-resistance testing.


METHODS
We did a prospective, open, randomised, controlled study of HIV-1-infected patients in whom combination therapy was not successful. We randomly assigned patients standard care (control, n=43) or treatment according to the resistance mutations in protease and reverse-transcriptase genes (genotypic group, n=65). The major endpoint was the change in HIV-1 RNA viral load. Analysis was by intention to treat.


RESULTS
108 patients were enrolled. All patients were similar for risk factors, age, sex, previous treatment, CD4-cell count (214/microL [SD14]) and log HIV-1 RNA viral load at baseline (4.7 copies/mL [0.1]). At month 3, the mean change in HIV-1 RNA was -1.04 log (0.14) in the study group compared with -0.46 log (0.17) in the control group (mean difference 0.58 log [95% CI 0.14-1.02], p=0.01). At month 6, changes were -1.15 (0.15) log copies/mL, and -0.67 (0.19) log copies/mL in the genotypic group and the control group, respectively (mean difference 0.48 log [0.01-0.97], p=0.05). Difference in the drop in viral load combined at 3 months and 6 months was significant (p=0.015). At month 3, HIV-1 RNA was lower than detection level (200 copies/mL) in 29% (19/65) of patients in the genotypic group versus 14% (6/43) in the control group (p=0.017). At month 6, the values were 32% (21/65) and 14% (6/43) (p=0.067) for the genotypic group and the control group, respectively. Therapy was generally well tolerated, with ten patients (six in the genotypic group, four in the control group) requiring toxic-effect-related drug modification.


CONCLUSIONS
We found genotypic-resistance testing to have a significant benefit on the virological response when choosing a therapeutic alternative. Further study of the use of genotypic-resistance testing in assisting clinical decision-making is warranted.
Department of Infectious Diseases, Archet Hospital, Nice, France.
J
J
Durant
P
P
Clevenbergh
P
P
Halfon
P
P
Delgiudice
S
S
Porsin
P
P
Simonet
N
N
Montagne
C A
CA
Boucher
J M
JM
Schapiro
P
P
Dellamonica
D000163:Acquired Immunodeficiency Syndrome / Q000188:drug therapy* / Q000235:genetics; D000328:Adult; D000465:Algorithms; D000704:Analysis of Variance; D019380:Anti-HIV Agents / Q000627:therapeutic use; D018791:CD4 Lymphocyte Count / Q000187:drug effects; D000075202:Contraindications; D004352:Drug Resistance, Microbial / Q000235:genetics; D010450:Endopeptidases / Q000235:genetics; D005260:Female; D005838:Genotype; D054303:HIV Reverse Transcriptase / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D010865:Pilot Projects; D011446:Prospective Studies; D011480:Protease Inhibitors / Q000627:therapeutic use*; D012367:RNA, Viral / Q000235:genetics; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use*
D019380:Anti-HIV Agents; D011480:Protease Inhibitors; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D054303:HIV Reverse Transcriptase; D010450:Endopeptidases