ObjectivesTo compare over 2 years the safety, efficacy and radiographic outcomes of subcutaneous abatacept versus adalimumab, in combination with methotrexate (MTX), in patients with rheumatoid arthritis (RA).MethodsAMPLE is a phase IIIb, 2-year, randomised, investigator-blinded study with a 1-year primary endpoint. Biologic-naive patients with active RA and an inadequate response to MTX were randomised to 125 mg abatacept weekly or 40 mg adalimumab bi-weekly, both with a stable dose of MTX.ResultsOf 646 patients randomised, 79.2% abatacept and 74.7% adalimumab patients completed year 2. At year 2, efficacy outcomes, including radiographic, remained comparable between groups and with year 1 results. The American College Rheumatology 20, 50 and 70 responses at year 2 were 59.7%, 44.7% and 31.1% for abatacept and 60.1%, 46.6% and 29.3% for adalimumab. There were similar rates of adverse events (AEs) and serious adverse events (SAEs). More serious infections occurred with adalimumab (3.8% vs 5.8%) including two cases of tuberculosis with adalimumab. There were fewer discontinuations due to AEs (3.8% vs 9.5%), SAEs (1.6% vs 4.9%) and serious infections (0/12 vs 9/19 patients) in the abatacept group. Injection site reactions (ISRs) occurred less frequently with abatacept (4.1% vs 10.4%).ConclusionsThrough 2 years of blinded treatment in this first head-to-head study between biologic disease-modifying antirheumatic drugs in RA patients with an inadequate response to MTX, subcutaneous abatacept and adalimumab were similarly efficacious based on clinical, functional and radiographic outcomes. Overall, AE frequency was similar in both groups but there were less discontinuations due to AEs, SAEs, serious infections and fewer local ISRs with abatacept.ClinicalTrials.gov IdentifierNCT00929864.

ObjectiveThere is a need for comparative studies to provide evidence-based treatment guidance for biologic agents in rheumatoid arthritis (RA). Therefore, this study was undertaken as the first head-to-head comparison of subcutaneous (SC) abatacept and SC adalimumab, both administered along with background methotrexate (MTX), for the treatment of RA.MethodsPatients with active RA who were naive to treatment with biologic agents and had an inadequate response to MTX were randomly assigned to receive 125 mg SC abatacept weekly or 40 mg SC adalimumab biweekly, both given in combination with MTX, in a 2-year study. The primary end point was treatment noninferiority, assessed according to the American College of Rheumatology 20% improvement response (ACR20) at 1 year.ResultsOf the 646 patients who were randomized and treated, 86.2% receiving SC abatacept and 82% receiving SC adalimumab completed 12 months of treatment. At 1 year, 64.8% of patients in the SC abatacept group and 63.4% in the SC adalimumab group demonstrated an ACR20 response; the estimated difference between groups was 1.8% (95% confidence interval −5.6%, 9.2%), thus demonstrating the noninferiority of abatacept compared to adalimumab. All efficacy measures showed similar results and kinetics of response between treatments. The rate of radiographic nonprogression (defined as a total modified Sharp/van der Heijde score [SHS] less than or equal to the smallest detectable change) was 84.8% for SC abatacept–treated patients and 88.6% for SC adalimumab–treated patients, while the mean change from baseline in the total SHS was 0.58 and 0.38, respectively. In the SC abatacept and SC adalimumab groups, the incidence of serious adverse events (SAEs) was 10.1% and 9.1%, respectively, and the rate of serious infections was 2.2% and 2.7%, respectively. In patients treated with SC abatacept, the frequency of discontinuations due to AEs was 3.5% and discontinuations due to SAEs was 1.3%, while in patients treated with SC adalimumab, the frequencies were 6.1% and 3%, respectively. Injection site reactions occurred in 3.8% of patients receiving SC abatacept compared to 9.1% of patients receiving SC adalimumab (P = 0.006).ConclusionThe results demonstrate that SC abatacept and SC adalimumab have comparable efficacy in patients with RA, as shown by similar kinetics of response and comparable inhibition of radiographic progression over 1 year of treatment. The safety was generally similar, other than the occurrence of significantly more local injection site reactions in patients treated with SC adalimumab.

ObjectivesTo examine whether baseline anti-cyclic citrullinated peptide-2 (CCP2) antibody status and concentration correlated with clinical outcomes in patients treated with abatacept or adalimumab on background methotrexate (MTX) in the 2-year AMPLE (Abatacept versus adaliMumab comParison in bioLogic-naïvE rheumatoid arthritis subjects with background MTX) study.MethodsIn this exploratory analysis, anti-CCP2 antibody concentration was measured at baseline, and antibody-positive patients were divided into equal quartiles, Q1–Q4, representing increasing antibody concentrations. Clinical outcomes analysed by baseline anti-CCP2 status and quartile included change from baseline in disease activity and disability and remission rates.ResultsBaseline characteristics were generally comparable across quartiles and treatment groups. In both treatment groups, anti-CCP2 antibody-negative patients responded less well than antibody-positive patients. At year 2, improvements in disease activity and disability and remission rates were similar across Q1–Q3, but were numerically higher in Q4 in the abatacept group; in contrast, treatment effects were similar across all quartiles in the adalimumab group.ConclusionsIn AMPLE, baseline anti-CCP2 positivity was associated with a better response for abatacept and adalimumab. Patients with the highest baseline anti-CCP2 antibody concentrations had better clinical response with abatacept than patients with lower concentrations, an association that was not observed with adalimumab.Trial registration numberNCT00929864.

Decay-accelerating factor (DAF, CD55) is a glycosylphosphatidylinositol-anchored membrane protein that restricts complement activation on autologous cells. It is also a ligand for CD97, an activation-associated lymphocyte antigen with seven transmembrane domains. It is widely expressed on cells of both the hematopoietic and nonhematopoietic lineages. Although deficiency of DAF on human erythrocytes is associated with the hemolytic anemia syndrome paroxysmal nocturnal hemoglobinuria, the in vivo biology of DAF is still poorly understood. We addressed the in vivo function of DAF in a knockout mouse model and describe here that deletion of DAF exacerbates autoimmune disease development in MRL/lpr mice, a model for human systemic lupus erythematosus. Compared to DAF-sufficient littermate controls, DAF-deficient female MRL/lpr mice developed exacerbated lymphadenopathy and splenomegaly, higher serum anti-chromatin autoantibody levels, and aggravated dermatitis. Consistent with the phenotype of aggravated dermatitis in DAF-deficient mice, Northern and Western blots and immunofluorescence studies showed DAF to be expressed abundantly in the mouse skin, suggesting that it may play a particularly important role in this tissue. Histology and immunostaining demonstrated inflammatory infiltrate and focal C3 deposition in early skin lesions, mostly along the dermal-epidermal junction. These results reveal a protective function of DAF in the development of a systemic autoimmune syndrome and suggest that dysfunction or down-regulation of DAF may contribute to autoimmune disease pathogenesis and manifestation.

Anti-dsDNA Abs are specific diagnostic markers of systemic lupus erythematosus, and are also implicated in kidney pathology. Anti-dsDNA B cells have been shown to be tolerized in nonautoimmune mice. The immunodysregulation that causes these cells to break tolerance is presumably part of the fundamental defects in systemic lupus erythematosus. To explore these mechanisms, we used the chronic graft-versus-host model mediated by MHC class II differences. Induction of chronic graft-vs-host in anti-DNA H chain knockin (3H9.KI) transgenic mice on a nonautoimmune background resulted in specific activation of anti-dsDNA B cells, as evidenced by high titers of soluble Ab in sera and a high frequency (70%) of anti-dsDNA B cell clones recovered as hybridomas. In addition, the λ+-anti-dsDNA B cells developed increased expression of cell surface activation markers, and concentrated in the T cell area of the follicle with an Ab-forming cell-compatible phenotype. Genetic analysis of the hybridoma clones showed strong evidence of secondary rearrangements of the L chain associated with anti-dsDNA reactivity. Thus, our study indicates that alloreactive T cell help can break tolerance in a complex manner, involving several events.

ObjectiveTo assess the ability of a multi‐biomarker disease activity (MBDA) test (Vectra DA) to reflect clinical measures of disease activity in patients enrolled in the AMPLE (Abatacept Versus Adalimumab Comparison in Biologic‐Naive RA Subjects with Background Methotrexate) trial.MethodsIn the AMPLE trial, patients with active rheumatoid arthritis (RA) who were naive to biologic agents and had an inadequate response to methotrexate were randomized (1:1) to receive subcutaneous abatacept (125 mg every week) or subcutaneous adalimumab (40 mg every 2 weeks), with background methotrexate, for 2 years. The MBDA score was determined using serum samples collected at baseline, month 3, and years 1 and 2. The adjusted mean change from baseline in the MBDA score was compared between the abatacept and adalimumab treatment groups. Cross‐tabulation was used to compare the MBDA score with the following clinical measures of disease activity: Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI), Disease Activity Score in 28 joints using the C‐reactive protein level (DAS28‐CRP), and Routine Assessment of Patient Index Data 3 (RAPID‐3).ResultsIn total, 318 patients were randomized to receive abatacept, and 328 were randomized to receive adalimumab; MBDA data were available for 259 and 265 patients, respectively. No association between the MBDA score and disease activity defined by the CDAI, SDAI, DAS28‐CRP, or RAPID‐3 in the abatacept and adalimumab treatment groups was observed.ConclusionThe MBDA score did not reflect clinical disease activity in patients enrolled in AMPLE and should not be used to guide decision‐making in the management of RA, particularly for patients who receive abatacept or adalimumab as the first biologic agent.

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The role of complement in the pathogenesis of autoimmune hemolytic anemia (AIHA) has been controversial and may depend on a number of factors, including the affinity and isotype of the pathogenic antibodies involved. We have recently shown that mouse erythrocytes deficient in the membrane C3 regulatory protein, complement receptor 1-related gene/ protein y (Crry), but not decay-accelerating factor (DAF), were spontaneously eliminated in vivo by complement. Here, by generating a mouse deficient in both DAF and Crry, we further delineated the roles of Crry and DAF in regulating alternative and classical pathway C3 activation. By using immunoglobulin-, Fc␥ receptor (Fc␥R)-, C3-, C4-, and C5-deficient mice, we also determined the mechanism by which membrane C3 regulator-deficient erythrocytes are cleared from the circulation. Finally, we evaluated the relative importance of the Fc receptor versus the complement pathway in disposing antibody-opsonized DAF/Crry-deficient erythrocytes. We conclude that (