Background/Purpose: BMI has been shown to affect treatment response and may influence the development of optimal individualized treatment plans in patients with RA.¹ The extent to which treatment response is influenced by BMI varies across biologic DMARDs and may be associated with mechanism of action.¹ We evaluated the impact of BMI on disease activity scores in patients receiving intravenous (IV) or subcutaneous (SC) abatacept as reported in the real-world AbataCepT In rOutiNe clinical practice (ACTION)² and Abatacept SubCutaneOus in Routine Clinical PracticE (ASCORE)³ studies in order to determine the impact of BMI on abatacept efficacy.

Methods: ACTION (NCT02109666) and ASCORE (NCT02090556) were international observational studies of patients with moderate-to-severe RA receiving IV (body weight–adjusted dosing) or SC (fixed dosing at 125 mg once weekly) abatacept, respectively, over 2 years.^2,3 In this post hoc analysis, patients were stratified by baseline BMI (high, ≥ 30 kg/m²; average, 25–< 30 kg/m²; low, < 25 kg/m²); patients were also stratified by abatacept treatment line (first-line; ≥ second line; all patients). Assessments were performed at month (M)6 and M12 and included mean (standard error) change from baseline in DAS28 (CRP), Clinical Disease Activity Index, Simplified Disease Activity Index, and HAQ-disability index (DI) scores. A last observation carried forward imputation method was applied for missing data. Differences between the three BMI categories were assessed using ANOVA test.

Results: 4868 patients were evaluated. Patient numbers and baseline disease activity scores were similar across BMI groups in both studies. Most patients had low BMI at baseline (Table 1). In patients receiving IV abatacept, there were no significant M12 differences across BMI groups for mean change from baseline across all measures of disease activity and physical function (HAQ-DI) in both treatment lines (Figure 1). In patients receiving SC abatacept, there were no significant M12 differences across BMI groups for mean change from baseline across all measures of disease activity and HAQ-DI in the first-line treatment group. However, in the ≥ second-line treatment group, significant differences across BMI groups were recorded for DAS28 (CRP) (P = 0.0211) and HAQ-DI scores (P = 0.0032).

Conclusion: BMI status did not significantly impact clinical efficacy in patients treated with IV abatacept. There were no significant differences between BMI categories for patients receiving IV abatacept as first- or ≥ second-line therapy. For SC abatacept, no significant differences across BMI groups were seen in the first-line group, but significant differences were seen in for DAS28 (CRP) and HAQ-DI scores in the ≥ second-line group. While results from clinical trials have shown that BMI has no impact on abatacept clinical efficacy, BMI was shown to significantly impact clinical responses in patients receiving abatacept as ≥ second- line therapy in a real-world observational setting.

References:
1. D’Agostino M-A, et al. Clin Rheumatol 2017;36:2655–2665.
2. Alten R, et al. Clin Rheumatol 2019;38:1413–1424.
3. Alten R, et al. Ann Rheum Dis 2019;78(Suppl 2):A1639.

Medical writing: Lindsay Craik (Caudex), funded by Bristol Myers Squibb

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/does-bmi-influence-the-efficacy-of-subcutaneous-or-intravenous-abatacept-in-patients-with-ra-in-routine-clinical-practice-a-post-hoc-analysis-of-two-real-world-observational-studies/