Abstract
Abatacept (ABA) is an immunosuppressant indicated for treatment of rheumatoid arthritis (RA). Effectiveness might be influenced by clinical RA variants and single-nucleotide polymorphisms (SNPs) in genes encoding protein FCGR2A (His131Arg) and FCGR3A (Phe158Val) involved in pharmacokinetics of ABA. An observational cohort study was conducted in 120 RA Caucasian patients treated with ABA for 6 and 12 months. Patients with the FCGR2A rs1801274-AA genotype (FCGR2A-p.131His) showed a better EULAR response (OR = 2.43; 95% CI = 1.01-5.92) at 12 months and low disease activity (LDA) at 6 months (OR = 3.16; 95% CI = 1.19-8.66) and 12 months (OR = 6.62; 95% CI = 1.25-46.89) of treatment with ABA. A tendency was observed towards an association between the FCGR3A rs396991-A allele (FCGR3A-p.158Phe) and better therapeutic response to ABA after 12 months of treatment (p = 0.078). Moreover, we found a significant association between the low-affinity FCGR2A/FCGR3A haplotypes variable and LDA after 12 months of ABA treatment (OR = 1.59; 95% CI = 1.01-2.58). The clinical variables associated with better response to ABA were lower age at starting ABA (OR = 1.06; 95% CI = 1.02-1.11) and greater duration of ABA treatment (OR = 1.02; 95% CI = 1.01-1.04), lower duration of previous biological therapies (OR = 0.99; 95% CI = 0.98-0.99), non-administration of concomitant disease-modifying antirheumatic drugs (DMARDs) (OR = 24.53; 95% CI = 3.46-523.80), non-use of concomitant glucocorticoids (OR = 0.12; 95% CI = 0.02-0.47), monotherapy (OR = 19.22; 95% CI = 2.05-343.00), lower initial patient's visual analogue scale (PVAS) value (OR = 0.95; 95% CI = 0.92-0.97), and lower baseline ESR (OR = 0.92; 95% CI = 0.87-0.97). This study showed that high-affinity FCGR2A-p.131His variant, low-affinity FCGR3A-p.158Phe variant, and combined use of FCGR2A/FCGR3A genetic variations could affect ABA effectiveness. Further studies will be required to confirm these results.