Benefits and Risks of Biologic DMARDs

Biologic DMARDs, also known as biologic agents, biologic response modifiers, or biologics, work by targeting a particular protein that contributes to rheumatoid arthritis (RA). Currently, four types of biologics are approved to treat RA and are named for the inflammatory proteins they target:

1. TNF-blockers -- (also called inhibitors) adalimumab (Humira), certolizumab pegol (Cimzia), etanercept (Enbrel), and infliximab (Remicade)

2. T-cell costimulator -- abatacept (Orencia)

3. B-cell inhibitor -- rituximab (Rituxan)

4. Interleukin-1 inhibitor -- anakinra (Kineret)

Biologic DMARDs may be used on their own or in combination with other treatments, including chemical DMARDs. The most common second step in rheumatoid arthritis therapy -- after methotrexate alone -- is combination therapy with methotrexate and a TNF-blocker. Other biologics may be used if TNF-blockers have not been effective, are not well tolerated, or are contraindicated.

A common but short-term side effect of all biologics is a skin reaction at the injection site. And all biologics increase the risk of infection, although to different degrees. TNF-blockers have been linked to serious fungal infections, tuberculosis (TB), and some cases of nerve damage; infliximab may cause severe allergic reactions; and rituximab has been linked to a rare but life-threatening brain infection. Compare biologic DMARDs with this table from the American College of Rheumatology.

Because these treatments are relatively new, their long-term side effects are not yet known.