Influence of -308 A/G polymorphism in the tumor necrosis factor alpha gene on etanercept treatment in rheumatoid arthritis.
OBJECTIVE
To determine whether the -308 A/G tumor necrosis factor alpha (TNFalpha) gene polymorphism can predict the outcome of etanercept therapy in 86 patients with rheumatoid arthritis (RA), as already observed in patients treated with infliximab.


METHODS
Eighty-six RA patients treated with etanercept were genotyped for -308 A/G TNFalpha gene polymorphism by polymerase chain reaction and melting curve analysis, using specific gene primers and probes. Patients were subdivided into group A (G/A genotype) and group G (G/G genotype). We compared clinical responses to etanercept between groups A and G after 6 months, using the Disease Activity Score in 28 joints (DAS28). After 12-month treatment, 48 of 86 patients were evaluated again.


RESULTS
Of 86 patients, 18 (21%) belonged in group A and 68 (79%) belonged in group G. After 6-month treatment, 55.6% of patients in group A and 82.4% of patients in group G had DAS28 improvement >1.2 (P = 0.027 by chi-square). The mean +/- SD DAS28 improvement was 1.69 +/- 1.31 in group A and 2.23 +/- 1.19 in group G (P = 0.098 by t-test). After 1-year treatment 48 patients were tested again: 10 (21%) belonged in group A and 38 (79%) belonged in group G. Forty percent of patients in group A and 87% in group G had DAS28 improvement >1.2 (P = 0.005 by chi-square). The mean +/- SD DAS28 improvement was 1.334 +/- 1.37 in group A and 2.29 +/- 1.47 in group G (Mann-Whitney U test = 115, P = 0.0057).


CONCLUSIONS
RA patients with a -308 G/G TNFalpha genotype respond to etanercept better than patients with a -308 A/G genotype.
Guis
Sandrine
S
INSERM UMR 639 and Assistance Publique Hôpitaux de Paris, Hôpital de la Conception, Marseille, France.
Balandraud
Nathalie
N
Bouvenot
Julien
J
Auger
Isabelle
I
Toussirot
Eric
E
Wendling
Daniel
D
Mattei
Jean-Pierre
JP
Nogueira
Leonor
L
Mugnier
Benedicte
B
Legeron
Pierre
P
Landt
Olfert
O
Serre
Guy
G
Roudier
Jean
J
Roudier
Chantal
C
D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000235:genetics; D000068800:Etanercept; D005260:Female; D005838:Genotype; D006801:Humans; D007074:Immunoglobulin G / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011237:Predictive Value of Tests; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use*; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics*
D018501:Antirheumatic Agents; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D000068800:Etanercept