Research has allowed us to better understand rheumatic diseases and this knowledge has led to the development of a new class of drugs called biological agents. They contain proteins that can specifically block some of the elements that are involved in the inflammatory process.


Inflammation in rheumatic diseases is a complicated process. Abnormal activation of various immune system cells, such as B cells, T cells, macrophages, and an increased production of different proteins called pro-inflammatory cytokines cause the inflammation that is responsible for the destruction of the joints.

the inflammatory process (1)

[1] Le Rhumatologue, Mars 2012 no 10

Download memory file


Biological agents, available since the early 2000s, have completely revolutionized the way we treat many forms of arthritis. These agents will still not heal the afflicted, but can induce remission in many patients. In addition to relieving the symptoms of arthritis, biological agents prevent the destruction of joints and the resulting disability.


Biological agents are considered when a patient has an inadequate response to traditional medication[c1] . If your arthritis remains active despite optimal treatment and the disease decreases your ability to function, your doctor may offer you to try a biological agent.


Currently, there are different biological agents with different mechanisms of action:

mechanism of action 

Available in french only

Further treatments are currently being developed.

Method of administration

Because biological agents are proteins, they must be injected in order not to be digested in the stomach. Some agents are injected under the skin and others are injected directly into a vein. The time to infuse the treatment and frequency of administration vary from product to product. Depending on your lifestyle, you might choose to go to a clinic regularly or to have a nurse come to your home for your biological agent intravenous treatment or sub-cutaneous injection.

Assessment before starting a Biologic agent

Before starting a biological agent, a basic check-up is usually necessary to ensure that the treatment can be started safely. This allows us to make sure there are no latent diseases which are diseases whose symptoms have not yet developed but could develop later. If you have ever been exposed to tuberculosis or hepatitis, it is likely that a treatment to cure those conditions will be considered before starting the biological agent.

Duration of treatment

Rheumatic diseases such as rheumatoid arthritis, psoriatic arthritis or ankylosing spondylitis are chronic diseases. You may need treatment for your entire life. However, it is possible to reduce the doses and even to stop treatment in some cases.

Possible side effects

Infections :

The risk of infection is increased with biological agents. However, this risk remains low considering the benefits these agents provide to patients. If you have an infection, if you have a fever, you should temporarily stop your biological agent, consult as soon as possible a doctor for proper care, and wait for recovery before resuming treatment.


Skin lesions:

         Psoriasis or eczema lesions have been reported in patients treated with anti-TNF agents.

         There may be inflammatory reactions at the injection sites. Generally, these reactions disappear in a few days.


Cancer :

The data is reassuring on this subject. However, the use of anti-TNF seems to slightly increase the risk of certain skin cancers. Therefore, measures should be taken to prevent this cancer risk: sunscreen, hat, regular skin examination.


We have described here the side effects that most worried patients. For a complete list of side effects that may occur with biologics, refer to the Product Monograph or click on the treatment names below to follow the links to the Arthritis Society's (AS) and Rheuminfo’s (RI) website. JointHealth also has a table tool that you can view here.

When to contact your doctor

  • If you have a fever or think you have an infection;

  • In case of surgery, biological agents must be temporarily interrupted for most surgical procedures because of the risk of infection. The duration of the interruption depends on the agent used, the type of surgery and the condition of the patient;

  • In case of dental surgery, notify the dentist that you are taking a biological agent before a dental procedure;

  • In case of pregnancy;

  • In case of skin reaction.