Chemotherapy for Autoimmune Rheumatic Disease
What is Chemotherapy for Autoimmune Rheumatic Disease?
Chemotherapy for autoimmune rheumatic diseases (ARDs) refers to the use of certain immunosuppressive or cytotoxic drugs - originally developed for cancer treatment - to control the overactive immune system that causes inflammation and tissue damage.
The immune system is the body’s defense network that protects against infections and harmful invaders. It includes organs, cells, and proteins that detect and destroy pathogens like bacteria, viruses, and abnormal cells.
ARDs are a group of conditions where the immune system mistakenly attacks the body's own tissues like the joints, muscles, and connective tissues. Common examples include rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), systemic sclerosis (scleroderma), dermatomyositis/polymyositis, vasculitis, and Sjögren’s Syndrome. Chemotherapy drugs suppress the immune response, helping to reduce inflammation, prevent joint and organ damage, and induce or maintain remission.
What are the Common Chemotherapy Drugs Used for Autoimmune Rheumatic Diseases?
Common chemotherapy drugs used for the treatment of autoimmune rheumatic diseases include the following:
- Methotrexate: This is the most commonly used drug in the treatment of rheumatoid arthritis and other ARDs. It is usually given as a weekly dose and helps reduce joint inflammation and slows disease progression.
- Cyclophosphamide: This is a potent immunosuppressive drug used for severe or life-threatening ARDs like lupus nephritis or vasculitis. It is usually given orally or intravenously. Due to its potential toxicity (e.g., bladder issues, infertility), it is often reserved for short-term use.
- Azathioprine: This drug is used as a maintenance therapy for lupus, myositis, and vasculitis. This is well-tolerated but requires monitoring for blood count and liver function.
- Mycophenolate Mofetil (MMF): This is commonly used in lupus nephritis, systemic sclerosis-related interstitial lung disease, and vasculitis. It is well-tolerated and effective in preventing flares.
- Leflunomide: This drug is used as an alternative to methotrexate in RA and psoriatic arthritis. It slows joint damage and reduces inflammation.
Risks and Side Effects
Chemotherapy drugs used for autoimmune rheumatic diseases can effectively control the underlying conditions, but they come with potential side effects and risks due to immune suppression and toxicity. These include:
- Infection risk (due to immune suppression)
- Nausea, fatigue
- Bone marrow suppression
- Hair thinning or loss
- Skin rashes
- Infertility
- Liver, lung, bladder, or kidney toxicity
- Cancer risk
Benefits
Benefits of chemotherapy drugs used for autoimmune rheumatic diseases include the following:
- Controls disease activity
- Prevents irreversible organ or joint damage
- May reduce the need for long-term steroid use
- Slows disease progression
- Induces remission
- Improves quality of life
Summary
Chemotherapy in autoimmune rheumatic disease is not "chemo" in a cancer sense, but a targeted use of immune-modulating drugs to manage serious inflammatory conditions. These drugs do not cure the disease but help manage symptoms and prevent serious complications like organ damage. Regular monitoring (blood counts, liver/kidney function) is essential while taking these drugs. It is often used alongside steroids, which are tapered as the chemo-type drug takes effect. It is a crucial tool for preventing complications and improving the quality of life in patients with autoimmune rheumatic diseases.
