Background and objectives Efficacy and tolerability of abatacept (ABA) is confirmed in randomised clinical trials. There isn’t enough data about results of ABA treatment in patients (pts) with different duration of rheumatoid arthritis (RA).

Objectives To analyse efficacy and safety of ABA treatment in pts with early (ERA) and long-standing (LS) RA.

Materials and methods Eighty patients with active RA were divided in two groups, the first one, less than three years duration (ERA - 51%) and the second one, more than three years duration (LS RA – 49%). Most of them were women, age 49 ± 13.5 years, with a high disease activity (DAS28=5.25 ± 1.15), RF-positive (75,7%) and ACPA-positive (75%). Disease activity was measured by DAS28, functional status – by HAQ-DI. Results were assessed every 12 weeks by EULAR criteria.

Results Pts had high disease activity by DAS28 (ERA DAS28–5.1 ± 0.9, LS RA - 5,3) and mild disability by HAQ-DI (ERA - 1.3 ± 0.6, LS RA - 1.6 ± 0.9) before treatment. Good and moderate response by EULAR criteria was achieved in 80% in the group of ERA and in 67% of pts with LS RA (p < 0.05) after 3 months of therapy. There was no significant difference in achieving good EULAR response between two groups after 6 months of therapy (43.75% - ERA; 38.4% - LS RA). The number of non-responders was similar after 3 months (ERA – 20%, LS RA – 31.4%) and 6 months (ERA – 18.7%, LS RA – 19.2%). After 3 months and 6 months the improvement of HAQ-DI in ERA group was significantly higher, than in LS RA group (p < 0.05). 28 adverse events (AE) in 17 (20%) pts were registered. One pt has herpes zoster and one, abscess of the right thumb.

Conclusion ABA has shown significant improvement in reduction of disease activity in pts with an inadequate response to previous therapy. There was no significant difference in achieving good EULAR response between pts with early and LS RA. However, pts in ERA group had significant improvement of HAQ-DI comparing with LS RA group. ABA has good safety profile, adverse events were registered only in 20% of pts.