Background/Purpose Abatacept is a biological anti-rheumatic drug used in Rheumatoid Arthritis (RA). Data on patient characteristics, diagnosis, previous treatment and outcomes of abatacept have been collected in the Swedish Rheumatology Quality register (SRQ) which comprises the Swedish Biologics Register (ARTIS; Arthritis Treatment In Sweden), since the drug was first available in 2006. The objective of this study was to evaluate drug survival probability and short term outcome of abatacept in clinical practice for patients with RA, using a national register.

Methods Observational data from the SRQ were collected for the period from April 1^st, 2006 to May 20, 2014. Analyses were stratified by previous exposure to biologics, regardless of the cause of discontinuation. Kaplan-Meier survival analysis with right censoring and log-rank test of equality across strata were performed and Šidák multiple-comparison adjustments applied. EULAR good or moderate response rates at 6 and 12 months were calculated, and corrected for survival on drug using the Lundex method (proportion still on drug x proportion responding(1)).

Results A total of 1291 patients with RA (1023 females, 79.2%) started abatacept treatment between April 2006 and May 2014. The mean age at start of abatacept was 59.2 years, and the median duration of RA was 11.2 years. Abatacept was prescribed as the first biologic treatment in 200 cases (15.5 %), after inadequate response (IR) to one other biologic in 349 cases (27.0 %) and after IR to ≥ 2 other biologics in 742 cases (57.5 %). The baseline disease activity was slightly lower in bio-naïve patients starting abatacept compared to those who had received one or ≥2 previous biologics (mean DAS28 5.01, 5.16 and 5.37 respectively). The bio-naïve patients treated with abatacept were older at baseline (mean 62.0 vs 60.6 and 57.8 years, respectively), and less likely to be female (71 % vs. 80 % and 81 %). Survival on drug was significantly longer in patients treated with abatacept as the first biologic compared to those previously exposed to 1 biologic (p=0.002) or ≥ 2 biologics (p=0.002). The corresponding estimated survival rates were 91%/77%/78% at 6 months and 75%/60%/62% at 12 months. There was no significant difference in drug survival between those with IR to one vs two biologics (p=0.94). After 6 months, among those still on treatment, a  EULAR good or moderate response was achieved in 74 % of patients in the bio-naïve subset compared to 62 % among those with previous IR to one biologic, and 57 % among those exposed to ≥ 2 biologics. The Lundex corrected EULAR good/moderate responses were 67%/48%/45% at 6 months and 47%/41%/37% at 12 months.

Conclusion In this observational study of RA patients treated with abatacept in clinical practice, a greater proportion of bio-naïve patients had a significant clinical response and remained on treatment compared to those with a previous IR to other biologic drugs. These results are compatible with reports from clinical trials, and indicate that a substantial number of RA patients treated with abatacept as their first biologic in clinical practice have a favorable outcome.

Reference: (1) Kristensen LE et al. Arthritis Rheum 2006; 54: 600-6

---

« Back to 2014 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/bio-naive-patients-with-rheumatoid-arthritis-benefit-more-from-abatacept-treatment-compared-to-those-who-are-inadequate-responders-to-other-biologics-results-from-the-national-swedish-rheuma/