Delaying Rheumatoid Arthritis with Abatacept: ARIAA Trial Findings

For people at high risk of developing rheumatoid arthritis (RA), early immune-targeted treatment offers a potential path to delaying or preventing disease onset.

Long-term data from the ARIAA trial, presented at the 2025 American College of Rheumatology conference, suggest that a 6-month course of abatacept could offer protection against the development of RA in high-risk individuals, at least temporarily.

Here’s a quick look at the trial and what it found.

Design of ARIAA

Participants in ARIAA were ACPA-positive, reported joint pain, and showed signs of subclinical inflammation—synovitis, tenosynovitis, or bone marrow edema—on MRI of the dominant hand.

They were randomized to receive 125 mg subcutaneous abatacept weekly or placebo for 6 months, followed by 12 months of observation without treatment. Researchers then conducted a long-term follow-up to assess the durability of abatacept’s effect on RA prevention.

Delayed RA Onset with Abatacept

Looking at the results, at the end of the treatment phase, only 8% of participants in the abatacept group had developed RA compared to 35% in the placebo group. After 18 months, the cumulative incidence rose to 35% for abatacept and 57% for placebo. This translated to an average gain of 15.3 RA-free weeks in the abatacept arm at study close.

Extended follow-up showed a convergence in RA incidence over time. By five years post-randomization, 69% in the abatacept group and 73% in the placebo group had developed RA.

Despite convergence, the average RA-free survival time remained about 40 weeks longer in the abatacept group. Notably, the slope of RA-free time gain showed initial catch-up post-treatment, followed by a period of durable separation through year five.

Predictive Features and Stratification

Descriptive comparisons showed that individuals who never developed RA had lower baseline ESR, lower rheumatoid factor levels, lower pain scores, and better functional status.

These baseline features may help identify which high-risk individuals are most likely to benefit from early immunomodulatory treatment.

Implications for Preventive Strategy

The long-term follow-up from ARIAA reframes RA prevention as a gain in disease-free time—an especially relevant measure in a condition with lifelong treatment implications.

The results support the concept that a short course of abatacept can meaningfully delay RA onset, even if it does not ultimately prevent progression in most individuals.

Limitations and Clinical Caution

The ultimate convergence of RA incidence between arms tempers enthusiasm. RA-free time gain, while clinically meaningful, may not represent disease modification in the strictest sense. Additionally, diagnosis post-trial was based on local physician discretion, introducing possible heterogeneity.

No significant differences in MRI scores or ACPA levels were observed across outcome groups, suggesting that serologic and clinical markers (e.g., RF, ESR, or pain) may be more informative for risk stratification than imaging alone in this setting.

Clinical Takeaway

A time-limited intervention with durable benefit suggests a potential role for preemptive treatment in selected RA patients. Identifying those with lower levels of systemic inflammation or better baseline function may further refine this strategy.

Ultimately, as risk stratification improves, early targeted therapy may become a viable component of RA delay or prevention in clinical practice.

Reference:
Tascilar K, Ostergaard M, Schoenau V, et al. Long-term prevention of RA in high-risk individuals after a 6-month placebo-controlled intervention with abatacept: the ARIAA trial [abstract]. Arthritis Rheumatol. 2025;77(suppl 9). https://acrabstracts.org/abstract/long-term-prevention-of-ra-in-high-risk-individuals-after-a-6-month-placebo-controlled-intervention-with-abatacept-the-ariaa-trial/. Accessed October 8, 2025.