Subcutaneous abatacept for the treatment of rheumatoid arthritis in routine clinical practice in Germany, Austria, and Switzerland: 2-year retention and efficacy by treatment line and serostatus.

INTRODUCTION/OBJECTIVES: The ASCORE study on treatment for rheumatoid arthritis (RA) showed better retention and clinical response rates for abatacept as first-line versus later-line therapy. This post hoc analysis of ASCORE assessed 2-year retention, efficacy, and safety of subcutaneous (SC) abatacept in Germany, Austria, and Switzerland. METHODS: Adults with RA who initiated SC abatacept 125 mg once weekly were assessed. Primary endpoint was abatacept retention rate at 2 years. Secondary endpoints: proportions of patients with low disease activity (LDA)/remission per Disease Activity Score in 28 joints based on erythrocyte sedimentation rate (≤ 3.2), Simplified Disease Activity Index (≤ 11), and Clinical Disease Activity Index (≤ 10). Outcomes were analyzed by treatment line and serostatus. RESULTS: For the pooled cohort, the 2-year abatacept retention rate was 47.6%; retention was highest in biologic-naïve patients (50.5% [95% confidence interval 44.9, 55.9]). Patients seropositive for both anti-citrullinated protein antibody (ACPA) and rheumatoid factor (RF; + / +) at baseline had a higher 2-year abatacept retention rate than patients with single seropositivity for either APCA or RF or double-seronegativity (- / -), irrespective of treatment line. At 2 years, a higher proportion of patients who were biologic-naïve were in LDA/remission than patients with one or ≥ two prior biologics. CONCLUSION: A higher proportion of patients with + / + RA (compared with - / - RA) had abatacept retention after 2 years. Early identification of patients with seropositive RA may facilitate a precision-medicine approach to RA treatment, leading to a higher proportion of patients in LDA/remission. TRIAL REGISTRATION NUMBER: NCT02090556; date registered: March 18, 2014 (retrospectively registered). Key Points • This post hoc analysis of a German-speaking subset of European patients with RA from the global ASCORE study (NCT02090556) showed that retention of SC abatacept within this subset was 47.6%, with good clinical outcomes after 2 years. • Patients with double-seropositive RA (ACPA and RF positive) had higher retention of abatacept than patients with double-seronegative RA (ACPA and RF negative). Retention and clinical responses were highest for patients who were biologic-naïve compared with patients who had one or ≥ two prior biologic treatments. • These real-world data may be useful for clinicians in informing individualized treatment pathways for patients with RA, and fostering superior disease control and clinical outcomes.

Retention of subcutaneous abatacept for the treatment of rheumatoid arthritis: real-world results from the ASCORE study: an international 2-year observational study.

OBJECTIVES: To evaluate retention, efficacy, and safety of subcutaneous (SC) abatacept over 2 years in patients with moderate-to-severe RA in the Abatacept SubCutaneOus in Routine clinical practicE (ASCORE) study. METHODS: Patients with RA who initiated SC abatacept 125 mg once weekly were enrolled in the international, observational, prospective multicentre ASCORE study into biologic-naïve or ≥ 1 prior biologic failure cohorts. PRIMARY ENDPOINT: abatacept retention rate at 2 years. Secondary endpoints: proportion of patients with good/moderate EULAR response rates based on DAS28 (ESR), low disease activity and/or remission according to DAS28 (ESR; ≤ 3.2/ < 2.6), SDAI (≤ 11/ ≤ 3.3), CDAI (≤ 10/ ≤ 2.8), and Boolean criteria. Retention rate by baseline serostatus was evaluated post hoc. RESULTS: Overall, 47% of patients remained on abatacept for 2 years, irrespective of treatment line. Higher abatacept retention rates were associated with lower prior biologic exposure. Generally, clinical outcomes showed that the proportion of patients with low disease activity/remission was higher in biologic-naïve patients (vs biologic-failure) and similar in those with 1 and ≥ 2 prior biologic failures. In patients on treatment at 2 years, good/moderate EULAR response rates of ~ 80% were consistently noted irrespective of prior biologic exposure. Across treatment lines, retention was greater in patients with seropositive (vs seronegative) RA. Patients with rheumatoid factor/anti-citrullinated protein antibody single-positive RA who were bio-naïve had higher retention than patients who were bio-experienced. CONCLUSIONS: In the ASCORE study, SC abatacept retention was 47% at 2 years with good clinical outcomes and was well-tolerated in the real-world setting. Abatacept retention and clinical response rates were higher in patients who received abatacept as an earlier- versus later-line biologic drug treatment and in those with seropositive RA. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02090556.

Abatacept retention and clinical outcomes in Austrian patients with rheumatoid arthritis: real-world data from the 2-year ACTION study.

BACKGROUND: AbataCepT In rOutiNe clinical practice (ACTION; NCT02109666) was a 2-year international observational study of patients with moderate to severe rheumatoid arthritis. METHODS: Baseline characteristics, abatacept retention rates, and clinical outcomes were compared by treatment line in the Austrian cohort of ACTION. RESULTS: Of 100 patients enrolled in Austria, 98 (98.0%) were evaluable: 33/98 (33.7%) biologic naïve and 65/98 (66.3%) with ≥1 prior biologic failure. At baseline, biologic-naïve patients had shorter disease duration and lower concomitant corticosteroid use than biologic-failure patients. Overall crude abatacept retention rate was 60.5% and retention rate was higher in biologic-naïve (65.1%) versus biologic-failure (58.0%) patients. Good/moderate EULAR (European League Against Rheumatism) response rates were 85.7% in biologic-naïve and 100% in biologic-failure patients. CONCLUSIONS: In the Austrian cohort of ACTION, overall abatacept retention at 2 years was high, with higher retention rates in patients receiving abatacept as an earlier treatment line. Good/moderate EULAR response rate was higher in biologic-failure than in biologic-naïve patients.

Abatacept retention and clinical outcomes in rheumatoid arthritis: real-world data from the German cohort of the ACTION study and a comparison with other participating countries.

INTRODUCTION: AbataCepT In rOutiNe clinical practice (ACTION; NCT02109666) was an observational study of patients with rheumatoid arthritis who initiated intravenous abatacept in clinical practice. We aimed to compare abatacept retention rates and clinical outcomes in patients from Germany versus other countries. METHOD: Baseline characteristics, crude retention rates, and clinical outcomes were compared by treatment line in the German cohort at 2 years. In addition, biologic-naïve patients were compared with biologic-naïve patients pooled from other participating countries. RESULTS: In the German cohort, 677/680 (99.6%) patients enrolled were evaluable and 171/677 (25.3%) were biologic naïve. At baseline, abatacept monotherapy was received by a similar proportion of biologic-naïve and biologic-failure patients in the German cohort, but by a greater proportion of biologic-naïve patients in German versus other countries cohort (27.5 vs. 12.9%). The overall crude abatacept retention rate at 2 years in the German cohort was 39.9%; retention rate did not differ significantly by treatment line, but among biologic-naïve patients it was lower in Germany than in the other countries cohort (42.1 vs. 58.7%; log-rank test p < 0.001). At 2 years, good/moderate European League Against Rheumatism (EULAR) response rates in biologic-naïve patients were 85.5% in the German and 92.1% in other countries cohort (p = 0.163). CONCLUSIONS: In the German cohort of ACTION, abatacept retention at 2 years was similar in biologic-naïve and biologic-failure patients. Biologic-naïve patients in German cohort had a significantly lower abatacept retention rate and a trend of lower good/moderate EULAR response rate than those in the other countries cohort. KEY POINTS: • Analyses of data from national patient cohorts provide insight on local treatment patterns. • In the German cohort of the ACTION study, abatacept retention at 2 years was similar in biologic-naïve and biologic-failure patients. • Biologic-naïve patients from the German cohort had a significantly lower abatacept retention rate and a trend of lower good/moderate EULAR response rate than patients from other countries. • Data from large international studies may not be directly applicable to individual countries.

Correction to: Predictors of abatacept retention over 2 years in patients with rheumatoid arthritis: results from the real-world ACTION study.

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Predictors of abatacept retention over 2 years in patients with rheumatoid arthritis: results from the real-world ACTION study.

OBJECTIVES: Evaluate abatacept retention over 2 years in the AbataCepT In rOutiNe clinical practice (ACTION) study. METHOD: ACTION was an international, observational study of patients with moderate-to-severe rheumatoid arthritis (RA) who initiated intravenous abatacept. Crude abatacept retention rates over 2 years were estimated using Kaplan-Meier analyses in biologic-naive and -failure patients. Clinically relevant risk factors and significant prognostic factors for retention were evaluated using a Cox proportional hazards multivariable model. RESULTS: Overall, 2350/2364 enrolled patients were evaluable; 673 (28.6%) were biologic naive and 1677 (71.4%) had prior biologic failure (1 biologic, 728/1677 [43.4%]; ≥ 2 biologics, 949/1677 [56.6%]). Abatacept retention rate (95% confidence interval [CI]) at 2 years was 47.9% (45.7, 50.0): 54.5% (50.4, 58.3) for biologic-naive vs 45.2% (42.7, 47.7) for biologic-failure patients (log-rank P < 0.001). For patients with 1 and ≥ 2 prior biologic failures, respectively, retention rates (95% CI) were 50.2% (46.3, 53.9) vs 41.3% (38.0, 44.6; log-rank P < 0.001). Main reasons for discontinuation (biologic-naive vs biologic-failure, respectively) were lack of efficacy (61.4 vs 67.7%) and safety (21.3 vs 21.2%). Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) double positivity versus negativity were predictive of higher retention in both biologic-naive (hazard ratio [HR] [95% CI] 0.71 [0.53, 0.96]; P = 0.019) and biologic-failure patients (HR [95% CI] 0.76 [0.62, 0.94]; P = 0.035). CONCLUSIONS: Abatacept initiation as earlier vs later line of therapy in RA may achieve higher 2-year retention rates. RF and anti-CCP seropositivity could predict increased abatacept retention, irrespective of treatment line. TRIAL REGISTRATION: NCT02109666.

Abatacept used in combination with non-methotrexate disease-modifying antirheumatic drugs: a descriptive analysis of data from interventional trials and the real-world setting.

BACKGROUND: Methotrexate (MTX) remains the anchor drug in rheumatoid arthritis (RA) treatment, but is poorly tolerated or contraindicated in some patients. There is a wealth of data supporting the use of abatacept in combination with MTX, but data on alternative conventional synthetic disease-modifying antirheumatic drug (csDMARD) combinations with abatacept are scarce. METHODS: In this post-hoc exploratory analysis, efficacy and safety data were extracted from abatacept RA studies in which combination with csDMARDs other than MTX was permitted: three interventional trials (ATTAIN, ASSURE, and ARRIVE) and one real-world study (ACTION). Patients with moderate-to-severe RA received abatacept in combination with MTX, hydroxychloroquine, sulfasalazine, azathioprine, or leflunomide for 6 months to 2 years according to the study design. Change from baseline in physical function (Health Assessment Questionnaire-Disability Index (HAQ-DI); all studies) and 28-joint Disease Activity Score (C-reactive protein) (DAS28 (CRP); ATTAIN, ARRIVE, and ACTION), American College of Rheumatology response rates (ATTAIN), and safety were assessed for individual and pooled csDMARD combinations for each trial. A meta-analysis was also performed on pooled data for HAQ-DI and DAS28 (CRP) across interventional trials. RESULTS: Across all four studies, 731 patients received abatacept plus one non-MTX csDMARD (hydroxychloroquine n = 152; sulfasalazine n = 123; azathioprine n = 59; and leflunomide n = 397) and 2382 patients received abatacept plus MTX. Mean changes from baseline in HAQ-DI scores for abatacept plus MTX (all csDMARDs pooled) vs abatacept plus a non-MTX csDMARD were -0.54 vs -0.44 (ATTAIN), -0.43 vs -0.43 (ASSURE), and -0.39 vs -0.36 (ARRIVE). Mean changes from baseline in DAS28 (CRP) and ACR response rates were also similar with abatacept plus MTX or non-MTX csDMARDs. Data for individual non-MTX csDMARDs (pooled across studies) and real-world data were consistent with these findings. Rates of treatment-related adverse events and serious adverse events, respectively, for abatacept plus one non-MTX csDMARD vs abatacept plus MTX were 35.7% vs 41.7% and 2.4% vs 2.3% (ATTAIN), 58.0% vs 55.9% and 4.2% vs 1.7% (ASSURE), and 38.1% vs 44.3% and 0.6% vs 2.9% (ARRIVE). CONCLUSIONS: Abatacept in combination with non-MTX csDMARDs is clinically effective and well tolerated in patients with moderate-to-severe RA, providing similar benefits to those seen with abatacept plus MTX. TRIAL REGISTRATION: ClinicalTrials.gov NCT00048581 . Registered 2 November 2002. ClinicalTrials.gov NCT00048932 . Registered 11 November 2002. ClinicalTrials.gov NCT00124982 . Registered 30 June 2005. ClinicalTrials.gov NCT02109666 . Registered 8 April 2014.

Baseline autoantibodies preferentially impact abatacept efficacy in patients with rheumatoid arthritis who are biologic naïve: 6-month results from a real-world, international, prospective study.

OBJECTIVES: To determine the impact of baseline rheumatoid factor (RF) and anticyclic citrullinated peptide (anti-CCP) status on the clinical efficacy of intravenous abatacept in biologic-naïve patients with rheumatoid arthritis (RA) enrolled in the real-world ACTION study. METHODS: Clinical outcomes (European League Against Rheumatism (EULAR) response, mean Clinical Disease Activity Index (CDAI) and Boolean remission) at 6 months were compared by baseline RF and anti-CCP status. RESULTS: Of 672 biologic-naïve patients, RF status was reported in 577 (86%) (412 (71%) positive) and anti-CCP status in 552 (82%) (364 (66%) positive); of 511 patients for whom data were available, 308/511 (60%) were double positive and 127/511 (25%) were double negative. Clinical outcomes were improved with RF-positive or anti-CCP-positive versus RF-negative/anti-CCP-negative status-good or moderate EULAR response: RF: 84.6 vs 72.9%, p=0.012; anti-CCP: 85.2 vs 74.2%, p=0.015; mean CDAI (calculated): RF: 10.8 vs 15.3, p<0.001; anti-CCP: 10.9 vs 14.3, p=0.002; and Boolean remission: RF: 13.3 vs 4.0%, p=0.008; anti-CCP: 12.5 vs 6.3%, p=0.096. Clinical outcomes were also improved with single or double RF-positive/anti-CCP-positive versus double-negative status. CONCLUSIONS: In biologic-naïve patients with RA, RF-positive and/or anti-CCP-positive status is associated with greater efficacy of intravenous abatacept than seronegative status. TRIAL REGISTRATION NUMBER: NCT02109666.

The effect of body mass index on clinical response to abatacept as a first-line biologic for rheumatoid arthritis: 6-month results from the 2-year, observational, prospective ACTION study.

OBJECTIVE: To assess the impact of baseline body mass index (BMI) on the efficacy and retention of intravenous abatacept at 6 months in biologic-naïve patients with rheumatoid arthritis (RA). METHODS: This was a 6-month analysis of a 2-year, non-interventional, international, prospective study. Baseline characteristics, clinical response and retention rates were compared by BMI subgroup: underweight/normal, overweight and obese (<25, 25 to <30 and ≥30kg/m2, respectively). RESULTS: BMI was reported in 643/672 (96%) patients: 264 (41%) were underweight/normal, 224 (35%) overweight and 155 (24%) obese. At baseline, the obese group had more active disease (mean [95% confidence intervals] 28-joint Disease Activity Score [C-reactive protein; derived] 4.6 [4.5, 4.7], 4.8 [4.7, 5.0] and 5.1 [4.9, 5.2] for underweight/normal, overweight and obese groups, respectively), a higher prevalence of metabolic disorders, a greater proportion of women and a lower proportion of patients with rheumatoid factor positivity. There were no significant differences in the percentages of patients achieving a good/moderate European League Against Rheumatism response by BMI group (80.7, 86.1 and 77.0% for underweight/normal, overweight and obese groups, respectively; P=0.178). Overall retention rates at 6 months did not differ across groups (89, 92 and 89% for underweight/normal, overweight and obese groups, respectively; log-rank P=0.382). After adjustment for baseline characteristics, BMI was not significantly associated with risk of discontinuation (reference BMI<25kg/m2; hazard ratio [95% confidence intervals] 0.46 [0.22, 0.99] and 0.69 [0.34, 1.41] for overweight and obese patients, respectively). CONCLUSION: BMI does not impact abatacept clinical response or retention in biologic-naïve patients with RA.

Real-world predictors of 12-month intravenous abatacept retention in patients with rheumatoid arthritis in the ACTION observational study.

INTRODUCTION: An understanding of real-world predictors of abatacept retention is limited. We analysed retention rates and predictors of abatacept retention in biologic-naïve and biologic-failure patients in a 12-month interim analysis of the 2-yearAbataCepTIn rOutiNe clinical practice (ACTION) study. METHODS: ACTION was an international, observational study of patients with moderate-to-severe rheumatoid arthritis (RA) who initiated intravenous abatacept. In this 12-month interim analysis, crude abatacept retention rates, predictors of retention and European League Against Rheumatism (EULAR) response were evaluated in both biologic-naïve and biologic-failure patients. Retention by rheumatoid factor (RF) and anti-cyclic citrullinated peptide (CCP) status was also assessed, in patients with or without baseline radiographic erosions, and by body mass index (BMI). RESULTS: Overall, 2350/2364 enrolled patients were evaluable (674 biologic naїve; 1676 biologic failure). Baseline characteristics were largely similar in biologic-naïve and biologic-failure groups. Crude retention rates (95% CI) at 12 months were significantly higher in biologic-naїve (78.1%(74.7% to 81.2%)) versus biologic-failure patients (69.9%(67.6% to 72.1%); P<0.001). RF/anti-CCP double positivity predicted higher retention in both patient groups, and remained associated with higher retention in patients with erosive disease. BMI did not impact abatacept retention in either patient group, irrespective of RF/anti-CCP serostatus. Good/moderate EULAR response rate at 12 months was numerically higher in biologic-naїve (83.8%) versus biologic-failure (73.3%) patients. There were no new safety signals. CONCLUSION: High levels of intravenous abatacept retention in clinical practice were confirmed, particularly in biologic-naïve patients, including in those with poor RA prognostic factors. Retention was unaffected by BMI, regardless of RF/anti-CCP serostatus. TRIAL REGISTRATION NUMBER: NCT02109666; retrospectively registered 8 April 2014.

Decreased use of glucocorticoids in biological-experienced patients with rheumatoid arthritis who initiated intravenous abatacept: results from the 2-year ACTION study.

INTRODUCTION: Prolonged glucocorticoid use may increase the risk of adverse safety outcomes, including cardiovascular events. The European League Against Rheumatism and the Canadian Rheumatology Association advise tapering glucocorticoid dose as rapidly as clinically feasible. There is a paucity of published data on RA that adequately describe concomitant treatment patterns. METHODS: ACTION (AbataCepT In rOutiNe clinical practice) is a non-interventional cohort study of patients from Europe and Canada that investigated the long-term retention of intravenous abatacept in clinical practice. We assessed concomitant glucocorticoids in patients with established RA who had participated in ACTION and received ≥1 biological agent prior to abatacept initiation. RESULTS: The analysis included 1009 patients. Glucocorticoids were prescribed at abatacept initiation in 734 (72.7%) patients at a median 7.5 mg/day dose (n=692). Of the patients who remained on abatacept at 24 months, 40.7% were able to decrease their dose of glucocorticoids, including 26.9% who decreased their dose from >5 mg/day to ≤5 mg/day. CONCLUSION: Reduction and/or cessation of glucocorticoid therapy is possible with intravenous abatacept in clinical practice.

Efficacy and prognostic factors of treatment retention with intravenous abatacept for rheumatoid arthritis: 24-month results from an international, prospective, real-world study.

OBJECTIVES: To evaluate retention of abatacept over 24 months in patients with rheumatoid arthritis (RA) in routine clinical practice across Europe and Canada. METHODS: ACTION (AbataCepT In rOutiNe clinical practice) was a prospective, observational, multicentre study of adult patients with moderate-to-severe RA who, at their physician's discretion, initiated treatment with intravenous abatacept. Enrolment occurred from May 2008 to December 2010, with up to 30 months of follow-up. The primary endpoint was the abatacept retention rate over 24 months. Crude abatacept retention rate was estimated using the Kaplan-Meier method. Prognostic factors of abatacept retention in patients with ≥1 prior biologic failure were derived from a Cox proportional hazards regression model, accounting for clustered data. RESULTS: A total of 1137 patients were enrolled (1573 patient-years on abatacept); most (89.2%) had experienced prior biologic failure. The overall crude abatacept retention rate at 24 months was 54.4% (95% confidence interval: 51.3, 57.4). Positivity for both rheumatoid factor and anti-cyclic citrullinated antibody, previous exposure to one or no anti-tumour necrosis factor agents, and cardiovascular comorbidity were prognostic of higher abatacept retention. Erythrocyte sedimentation rate ≥51 mm/hour and introduction of corticosteroid use at abatacept initiation were predictors of lower abatacept retention. Abatacept retention varied according to country. Abatacept was well tolerated without any unexpected safety signals. CONCLUSIONS: In a real-world setting, intravenous abatacept treatment retention was more than 50% at 24 months. The identification of prognostic factors of abatacept retention could support individualised biologic treatment strategies in patients with moderate-to-severe RA.

Prognostic factors for abatacept retention in patients who received at least one prior biologic agent: an interim analysis from the observational, prospective ACTION study.

BACKGROUND: The emergence of new therapies for the treatment of rheumatoid arthritis (RA), the paucity of head-to-head studies, and the heterogeneous nature of responses to current biologics highlight the need for the identification of prognostic factors for treatment response and retention in clinical practice. Prognostic factors for patient retention have not been explored thoroughly despite data for abatacept and other biologics being available from national registries. Real-world data from the ACTION study may supplement the findings of randomized controlled trials and show how abatacept is used in clinical practice. The aim of this interim analysis was to identify prognostic factors for abatacept retention in patients with RA who received at least one prior biologic agent. METHODS: A large, international, non-interventional cohort of patients with moderate-to-severe RA who initiated intravenous abatacept in Canada and Europe (May 2008-January 2011) enrolled in the ACTION study. Potential prognostic factors for retention in this interim analysis (data cut-off February 2012; including patients from Canada, Germany, Greece, and Italy) were baseline demographics and disease characteristics, medical history, and previous and concomitant medication. Clinically relevant variables with p ≤ 0.20 in univariate analysis and no collinearity were entered into a Cox proportional hazards regression model, adjusted for clustered data. Variables with p ≤ 0.10 were retained in the final model (backward selection). RESULTS: The multivariate model included 834 patients. Anti-cyclic citrullinated peptide (CCP) antibody positivity (hazard ratio [95% confidence interval]: 0.55 [0.40, 0.75], p < 0.001), failure of <2 prior anti-tumor necrosis factors (TNFs) (0.71 [0.56, 0.90], p = 0.005 versus ≥2 prior anti-TNFs), and cardiovascular comorbidity at abatacept initiation (0.48 [0.28, 0.83], p = 0.009) were associated with lower risk of abatacept discontinuation. Patients in Greece and Italy were less likely to discontinue abatacept than patients in Germany and Canada (Greece: 0.30 [0.16, 0.58]; Italy: 0.50 [0.33, 0.76]; Canada: 1.04 [0.78, 1.40], p < 0.001 versus Germany). CONCLUSIONS: Real-world prognostic factors for abatacept retention include anti-CCP positivity and fewer prior anti-TNF failures. Differences in retention rates between countries may reflect differences in healthcare systems. The finding that abatacept has potential advantages in patients with cardiovascular comorbidities needs to be confirmed in further research.

Real-world effectiveness of abatacept for rheumatoid arthritis treatment in European and Canadian populations: a 6-month interim analysis of the 2-year, observational, prospective ACTION study.

BACKGROUND: Discontinuation of rheumatoid arthritis (RA) treatment for lack or loss of initial response, tolerability issues, or development of antibodies against the therapeutic agent remains a challenge in clinical practice. Here we present a 6-month interim analysis of a 2-year prospective observational trial in Europe and Canada aiming to assess the real-world effectiveness, safety, and tolerability of intravenous abatacept for the treatment of moderate-to-severe RA. METHODS: ACTION (AbataCepT In rOutiNe clinical practice) is a prospective, observational study assessing effectiveness, safety, and tolerability of abatacept in patients with RA enrolled in Europe and Canada between May 2008 and January 2011. The patient population was divided into two groups: biologic naïve ('first-line') patients and patients who had previously failed treatment with at least one biologic agent ('second-line'). Retention rates were calculated using Kaplan-Meier curve estimates. Effectiveness was measured using European League Against Rheumatism (EULAR) response criteria, the 28-item Disease Activity Score, the Clinical Disease Activity Index (CDAI), and physical function, as assessed by the Health Assessment Questionnaire-Disability Index (HAQ-DI). Serious adverse events (SAEs) were reported for all enrolled patients. RESULTS: Of 1138 consecutively enrolled patients, 1114 and 1079 patients were evaluable for retention and effectiveness, respectively. Overall, retention rates were 88.6% (95% confidence interval [CI]: 86.4, 90.4); 67.4% of patients achieved good/moderate EULAR response; 32.8% had a CDAI Low Disease Activity State (LDAS); and 44.7% a HAQ-DI response. Retention rates among first- and second-line patients were 93.0% (95% CI: 85.9, 96.6) and 88.1% (95% CI: 85.7, 90.0), respectively. The percentage of patients achieving CDAI LDAS was 40.0% (95% CI: 26.4, 53.6) for first- and 32.2% (95% CI: 28.4, 36.0) for second-line patients and the proportion achieving a HAQ-DI response was 60.3% (95% CI: 47.8, 72.9) versus 43.1% (95% CI: 39.0, 47.2), respectively. The incidence of SAEs was 4.7%. CONCLUSIONS: Evidence from this 6-month interim analysis suggests that abatacept offers an effective and well-tolerated treatment option for patients with RA, including those who have previously failed anti-tumor necrosis factor treatment. In addition, higher retention rates and effectiveness outcomes were observed when abatacept treatment was initiated earlier in the course of the disease.