Is it possible to predict if a patient will respond well to tocilizumab?

The study aimed to identify the features that are associated with a better response to tocilizumab (Actemra) in patients with rheumatoid arthritis (RA). The authors concluded that patients who experience RA in areas other than the joints (extra-articular) are significantly more likely to respond well to tocilizumab.

In rheumatoid arthritis (RA), the immune system attacks the healthy joints the way it would a virus or bacteria. Patients experience inflammation and pain in the joint as a result. In more severe cases of RA a patient might experience swelling and pain in organs other than the joints. This is known as extra-articular RA.

The first treatments developed for RA were designed to reduce this inflammation. In recent years biological drugs have been developed with the aim of eliminating the symptoms completely, also known as remission. Tocilizumab is a biological drug that is prescribed to patients who have not responded to one or more other treatments.

Some patients do not respond well to biological drugs, and they may cause unwanted side effects. It would be beneficial to know if a patient will respond to a biological drug before beginning treatment to avoid unnecessary side effects. 

This study included 126 RA patients receiving tocilizumab treatment. A number of characteristics including age, gender, disease duration, presence of extra-articular RA, previous treatments and disease activity were recorded at the start of the study for all patients.  

At 3 months, 31% of patients achieved remission and 82% showed a good response to tocilizumab. At 6 months 40% achieved remission and 86% showed a good response.

Patients with extra-articular RA were 15.45 times more likely to achieve remission. Patients with higher levels of a blood marker for inflammation were 19 times more likely to achieve remission. Patients with high disease activity were 70% less likely to achieve remission. Patients who previously received more disease-modifying anti-rheumatic drugs (DMARDS) were 59% less likely to achieve remission. Patients who previously received other biological drugs were 67% less likely to achieve remission. 

The authors concluded that patients with extra-articular RA are more likely to respond well to tocilizumab. However, patients with high disease activity or who have previously failed to respond well to other treatments are less likely to achieve remission with tocilizumab.

This study was carried out in a small number of patients. Factors that were significant at 3 months were not all significant at 6 months.