Head-to-Head at 2 Years, Abatacept Equals Adalimumab for RA

Schiff M, Weinblatt ME, Valente R, et al. Head-to-head comparison of subcutaneous abatacept versus adalimumab for rheumatoid arthritis: two-year efficacy and safety findings from AMPLE trial. Ann Rheum Dis. (2013) 0:1-9 [Online First: Aug 26, 2013] doi:10.1136/annrheumdis-2013-203843

Final 2-year results from the international AMPLE Trial , first reported at the European Union League Against Rheumatism (EULAR) meeting in Madrid last July, are now published online with full text available for free. The first head-to-head comparison of abatacept (Orencia) and adalimumab (Humira) showed nearly identical clinical, functional, and radiographic benefits for either drug when added to methotrexate (MTX) for early rheumatoid arthritis (RA) patients.

The trial randomized 646 biologic-nave patients with moderate to high RA activity (mostly white women in their 50s) to take background MTX plus either 125 mg of subcutaneous abatacept weekly (n=318) or  40 mg adalimumab biweekly (n=328), also subcutaneously.

Patients in the multicenter study had been unresponsive to MTX, so their MTX doses varied: ≥15 mg/wk, ≤25 mg/week, or ≥7.5 mg/week (the latter for patients who could not tolerated higher doses). All doses were titrated downward in year 2.

Among the results:

•    An ACR20 response for 59.7% of the abatacept group and 60.1% of adalimumab-treated patients. Response rates at ACR 50, 70, and 90 levels were comparable.

•    30.2% of patients overall achieved a major clinical response (ACR 70 for ≥6 months).

•    More than two-thirds of patients in both groups achieved DAS28-CRP scores of ≤3.2.

•     Over 65% of patients in both groups had low disease activity based on CDAI, SDAI and ACR/EULAR criteria.

•     Up to 32% of patients attained remission according to CDAI and SDAI, and 20% met ACR/EULAR Boolean-based criteria.

•     Functional improvement was comparable for both drugs. HAQ-DI scores improved for about half of patients.

•     Radiographic non-progression rates at 2 years (total Sharp Scores) were also similar: 84.8% for abatacept and 83.8% for adalimumab.

A majority of patients completed 2 years. More than twice as many patients discontinued adalimumab because of adverse events (9.1%, as against 3.5% for abatacept). Discontinuations due to lack of efficacy were more similar (6.0% for abatacept and 4.9% for adalimumab).