Phenotypic or genotypic resistance testing for choosing antiretroviral therapy after treatment failure: a randomized trial.
OBJECTIVE
To assess the respective value of phenotype versus genotype versus standard of care for choosing antiretroviral therapy in patients failing protease inhibitor-containing regimens.


METHODS
Patients with plasma HIV-1 RNA exceeding 1000 copies/ml were randomly allocated to phenotyping, genotyping, or standard of care.


RESULTS
Five-hundred and forty-one patients were randomized, 190 to phenotyping, 192 to genotyping and 159 to standard of care. The baseline median CD4 cell count (280 x 106 cells/l), the plasma HIV-1 RNA level (4.3 log10 copies/ml), and the number of drugs previously received (n = 6) were similar in the three arms. More patients in the standard-of-care arm received at least three new drugs (55% versus 20% in the other arms; P < 0.001) and a regimen containing drugs from the three different classes. Plasma HIV-1 RNA was < 200 copies/ml at week 12 in 35% of patients in the phenotyping arm, 44% in the genotyping arm and 36% in the standard-of-care arm (phenotyping versus standard of care, P = 0.918; genotyping versus standard of care, P = 0.120). In a secondary analysis of 179 patients experiencing a first protease inhibitor failure, the percentage of patients achieving HIV-1 RNA < 200 copies/ml was significantly higher in the genotyping arm (65%) than in the phenotyping (45%) and the standard-of-care arms (45%) (genotyping versus standard of care, P = 0.022).


CONCLUSIONS
Overall, resistance assays did not demonstrate benefit over standard of care. In patients with the most limited protease inhibitor experience, a significant benefit was observed in the genotyping arm.
Meynard
Jean-Luc
JL
INSERM SC4, Hôpital Saint-Antoine, Paris, France.
Vray
Muriel
M
Morand-Joubert
Laurence
L
Race
Esther
E
Descamps
Diane
D
Peytavin
Gilles
G
Matheron
Sophie
S
Lamotte
Claire
C
Guiramand
Sonia
S
Costagliola
Dominique
D
Brun-Vézinet
Françoise
F
Clavel
François
F
Girard
Pierre-Marie
PM
D019380:Anti-HIV Agents / Q000493:pharmacokinetics / Q000627:therapeutic use*; D018791:CD4 Lymphocyte Count; D011307:Drug Prescriptions; D024882:Drug Resistance, Viral / Q000235:genetics; D004361:Drug Tolerance; D005838:Genotype; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000276:immunology / Q000821:virology; D017320:HIV Protease Inhibitors / Q000493:pharmacokinetics / Q000627:therapeutic use*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D010349:Patient Compliance; D010641:Phenotype; D011446:Prospective Studies; D018894:Reverse Transcriptase Inhibitors / Q000493:pharmacokinetics / Q000627:therapeutic use*; D017211:Treatment Failure; D019562:Viral Load
D019380:Anti-HIV Agents; D017320:HIV Protease Inhibitors; D018894:Reverse Transcriptase Inhibitors