Comparison of infliximab, adalimumab and etanercept in rheumatoid arthritis

The authors compared the duration of time from initiation to discontinuation of therapy between three drugs: infliximab (Remicade), adalimumab (Humira) and etanercept (Enbrel) in rheumatoid arthritis (RA). 

In RA, the immune system attacks healthy tissues instead of viruses or bacteria. This can cause inflammation, leading to chronic pain. Often times, RA patients who achieve reduction of symptoms from a certain treatment tend to continue with the same treatment unless they experience severe side effects. This is known as persistence and is mostly applicable to anti-TNF RA treatments. TNF refer to a group of proteins involved in the inflammation process in RA. Anti-TNF treatment blocks the action of TNF and prevents inflammation. Examples of such treatments include infliximab, adalimumab, and etanercept. Substantial differences exist between these three drugs in terms of benefit and side effects.

The differences in persistence between these three drugs need to be analyzed. 

The authors aimed to compare persistence between infliximab, adalimumab and etanercept in RA patients.

2,923 patients were included in this study. 63% of patients were treated with etanercept (group1). 21% of patients were treated with infliximab (group 2). 16% of patients were treated with adalimumab (group 3). Persistence was measured as the time between first dose of the drug to discontinuation. Drug discontinuation was defined as a drug-free period of 180 days or switching to another anti-TNF drug or other RA drug.

The median (mid-point) persistence in group 1 patients was 3.8 years. It was 3.7 years in group 2 and 3.3 years in group 3. When compared to group 1, patients in group 2 had a 2% reduced risk of discontinuation. Compared to patients in group 3, patients in group 2 had a 5% reduced risk of discontinuation. The risk of discontinuation was similar between patients in group 1 and group 3. 

The authors concluded that infliximab, adalimumab, and etanercept had similar persistence in RA patients. They further suggested that these three drugs could possibly have similar benefits as well as similar side-effects.