Biologic Response Modifiers
Biologic response modifiers (BRMs) are among the newest drugs used to treat rheumatoid arthritis and other rheumatic conditions.
Biologic response modifiers, a drug class of their own, are medicines which are based on compounds that are made by living cells. As these drugs became available, patients suddenly had newer treatment options and renewed hope. Rheumatologists suddenly had better options for treating the disease.
Biologic Therapies
As Enbrel (etanercept) was FDA-approved in late 1998 and as Remicade (infliximab) followed in 1999, it was an exciting time in the world of rheumatology. What was so different this time? New arthritis medications had come out before, some with more fanfare than others, but something was different about biologic response modifiers. What was it all about and why were expectations riding so high?
Biological therapy, also referred to as immunotherapy or biotherapy, employ biologic response modifiers to stimulate or restore the ability of the immune system to fight disease and/or infection. Biologics can include:
TNF Blocker Drugs
TNF blocker drugs target the effects of TNF-alpha. TNF blocker drugs now include:
TNF-alpha is one of the most important cytokines involved in rheumatoid arthritis through its entanglement in the cascade of inflammatory reactions. TNF blockers bind to TNF-alpha, rendering it inactive, and interfering with inflammatory activity, ultimately decreasing joint damage.
From Johns-Hopkins website, "Tumor necrosis factor-alpha and interleukin-1 (IL-1) are the major macrophage-derived cytokines present in the rheumatoid joint."
Kineret (Anakinra)
Kineret (anakinra) is considered an IL-1 antagonist. Kineret is the first selective blocker of interleukin-1 (IL-1), a protein which is found in excess in rheumatoid arthritis patients. By blocking IL-1, Kineret inhibits inflammation and pain associated with rheumatoid arthritis. Kineret can be used alone, or in combination with DMARDs (disease-modifying anti-rheumatic drugs) other than anti-TNF drugs.Most rheumatolgists have not used Kineret commonly to treat rheumatoid arthritis due to its decreased effectiveness and need to inject daily. Kineret has been very useful in patients who have been diagnosed with a systemic form of juvenile arthritis called Still's disease.
Orencia (Abatacept)
Orencia (abatacept) is the first T-cell co-stimulation modulator approved for the treatment of rheumatoid arthritis. Orencia was FDA-approved in December 2005. Orencia is expected to be available to patients sometime after February 2006.
Rituxan (Rituximab)
In March 2006, Rituxan (rituximab), the world's best-selling cancer drug, was FDA-approved to be used in combination with the drug methotrexate to treat rheumatoid arthritis by reducing the signs and symptoms in adult patients who have moderately-to-severely active rheumatoid arthritis and have failed one or more anti-TNF drugs e.g. Enbrel (etanercept), Remicade (infliximab), or Humira (adalimumab).
Rituxan selectively targets CD20-positive B-cells (b-lymphocytes). Rituxan is the first treatment for rheumatoid arthritis which selectively targets the CD20-positive B-cells.
The Future Of Biologics
When BRMs became available, rheumatologists were initially optimistic and anticipated great results for many patients. Though the drugs are contraindicated for some patients, many rheumatoid arthritis patients have greatly benefited and found sustained relief while being treated with biologics. Several BRMs are also being used to treat other types of arthritis and related rheumatic conditions. The biologics are an important class of drugs and more are in development.
Related Resources - Biologic Response Modifiers
Sources: Conquering Rheumatoid Arthritis: The Latest Breakthroughs and Treatments, by Thomas F. Lee, Ph.D.; Biological Therapy, MedicineNet.com; Anti-TNF Therapy for RA, Johns Hopkins Arthritis
