Year 2 data has shown similar efficacy between Abatacept ( Orencia ) plus Methotrexate ( MTX ) and Adalimumab ( Humira ) plus Methotrexate, consistent with the year 1 result which demonstrated comparable efficacy based on a non-inferiority endpoint for ACR 20 response.
Radiographic non-progression at 2 years was achieved by 85% of patients on Abatacept plus MTX and 84% of patients on Adalimumab plus Methotrexate.

The frequency of adverse events was overall similar in both groups; there were numerically fewer discontinuations due to adverse events, serious adverse events, serious infections, and fewer local injection site reactions in patients treated with Abatacept plus Methotrexate.

Of 646 patients with moderate to severe rheumatoid arthritis who were randomized and treated, 79.2% ( 252 of 318 ) Abatacept plus MTX patients and 74.7% ( 245 of 328 ) Adalimumab plus MTX patients completed the full 24 month study.
Comparable ACR20 response rates at year two were 59.7% for Abatacept plus MTX and 60.1% for Adalimumab plus MTX.
Onset of response was also generally comparable between the two groups for ACR20, 50 and 70 with responses remaining comparable through two years.

Additionally, 30.2% patients in both treatment groups showed a major clinical response ( an ACR70 score maintained for greater than or equal to 6 months ) at two years. A DAS28-CRP score less than or equal to 3.2 was achieved by 65.3% of Abatacept plus MTX patients and 68.0% of Adalimumab plus MTX patients, while 50.6% of Abatacept plus MTX and 53.3% of Adalimumab plus MTX achieved a score less than 2.6.

Paired radiographic images were available at baseline and year two for 80.8% ( 257/318 ) and 79.3% ( 260/328 ) of patients in the Abatacept plus MTX and Adalimumab plus MTX groups respectively. The distribution of change in total score from baseline to year two showed that inhibition of radiographic damage was similar in both treatment groups, and included most patients. Inhibition of radiographic progression was seen in both component scores ( Erosion Score: 0.4 ± 2.6 and 0.4 ± 5.0; Joint Space Narrowing Score: 0.5 ± 2.2 and 0.7 ± 3.8 ) in the Abatacept plus MTX and Adalimumab plus MTX groups respectively.
At year two, the non-progression rate ( change from baseline less than or equal to SDC =2.2 ) was 84.8% and 83.8% in the Abatacept plus MTX and Adalimumab plus MTX groups respectively.

At year two, the cumulative rates of adverse events ( AEs ) were 92.8% and 91.5%, and serious adverse events were 13.8% and 16.5%, in the Abatacept plus MTX and Adalimumab plus MTX groups, respectively. Discontinuations due to AEs occurred in 3.8% and 9.5% of the Abatacept plus MTX and Adalimumab plus MTX patients respectively ( estimate of difference: -5.7 [ 95%CI: -9.5, -1.9 ] ). Discontinuations due to SAEs occurred in 1.6% and 4.9% in the Abatacept plus MTX and Adalimumab plus MTX groups respectively ( estimate of difference: -3.3 [ 95%CI: -9.5, -1.9 ] ).
One death occurred in each treatment group, neither of which was attributed to the study medications.
Overall, 76.1% of the Abatacept plus MTX patients and 71.3% of the Adalimumab plus MTX patients had an infection over two years.
During the study period, serious infections occurred in 12 ( 3.8% ) and 19 ( 5.8% ) patients of which five and 10 occurred during year two, for Abatacept plus MTX vs Adalimumab plus MTX, respectively.

Discontinuations due to serious infections were zero of the 12 patients with serious infections for Abatacept plus MTX compared to nine of the 19 patients with serious infections, for Adalimumab plus MTX.

Injection site reactions were reported in 4.1% of patients taking Abatacept plus MTX and 10.4% of patients taking Adalimumab plus MTX over two years.

Autoimmune events, of moderate or mild severity, were reported in 12 patients (3.8%) in the Abatacept plus MTX group and six patients ( 1.8% ) in the Adalimumab plus MTX group.

Malignancies occurred in seven patients ( 2.2% ) in the Abatacept plus MTX group and seven patients ( 2.1% ) in the Adalimumab plus MTX group.

Orencia SC and IV is indicated for reducing signs and symptoms, inducing major clinical response, inhibiting the progression of structural damage, and improving physical function in adult patients with moderately to severely active rheumatoid arthritis. Orencia may be used as monotherapy or concomitantly with disease-modifying antirheumatic drugs ( DMARDs ) other than tumor necrosis factor ( TNF ) antagonists.
Orencia IV is indicated for reducing signs and symptoms in pediatric patients 6 years of age and older with moderately to severely active polyarticular juvenile idiopathic arthritis. Orencia IV may be used as monotherapy or concomitantly with methotrexate ( MTX ). Orencia SC has not been studied in pediatric patients.

Orencia should not be administered concomitantly with TNF antagonists. Orencia is not recommended for use concomitantly with other biologic rheumatoid arthritis ( RA ) therapy, such as Anakinra ( Kineret ).

Source: European League Against Rheumatism ( EULAR ) Congress, 2013

XagenaMedicine2013