Conventional drugs are chemically synthesized. Of the four currently licensed biologics, three help reduce inflammation and structural damage of the joints by blocking a substance called tumor necrosis factor (TNF), a protein involved in immune system responses. Elevated levels of TNF are found in the synovial fluid of rheumatoid and some other arthritis patients.
The first biologic to receive FDA approval for patients with moderate-to-severe RA was Enbrel (etanercept). Initially, it was taken twice weekly by injection, but a once-weekly preparation is now available. Enbrel has been shown to decrease pain and morning stiffness and improve joint swelling and tenderness. In 2000, the drug's approved uses were expanded to include delaying structural damage. Besides RA, Enbrel now has been approved for two other common forms of arthritis: psoriatic arthritis and ankylosing spondylitis.
The two other TNF-blocking products approved to treat RA are Remicade (infliximab) and Humira (adalimumab), a drug that provided the long-awaited relief for Shirley through a 2002 clinical trial. All three TNF blockers have been demonstrated to improve physical function in studies of at least two years in duration.
"While all three inhibit the action of TNF," says Jeffrey N. Siegel, M.D., team leader for the FDA's Division of Therapeutic Biological Internal Medicine Products, "they do it in somewhat different ways." Remicade and Humira are monoclonal antibodies, laboratory-produced proteins similar to those made by a person's immune system that bind and remove TNF from the body before it can set off the immune reaction responsible for RA.
Enbrel, on the other hand, is a soluble cytokine receptor, which means it is similar in structure to protein molecules found attached to the surface of cells that bind TNF. Enbrel competes with these receptors to inhibit them from binding TNF, thus blocking them from setting off the immune process responsible for RA, psoriatic arthritis, and ankylosing spondylitis.
Siegel warns that caution is important when using these agents as treatments. "All TNF blockers are associated with infection," he says.
Kineret (anakinra), another biologic approved by the FDA for patients with RA, has been shown in clinical trials to improve pain and swelling and slow the progression of structural damage in patients.
Arthritis Treatment Devices
Two medical device products, Hyalgan and Synvisc, are preparations that mimic a naturally occurring body substance that lubricates the knee joint called hyaluronic acid. The products, which were approved by the FDA for the treatment of OA of the knee, are injected directly into the knee joint to help provide temporary relief of pain and flexible joint movement.
Another device used in arthritis treatment is transcutaneous electrical nerve stimulation (TENS), which has been found effective in modifying pain perception. TENS blocks pain messages to the brain by directing mild electric pulses to nerve endings that lie beneath the painful area of the skin.
A blood-filtering device called the Prosorba Column is used in some cases for filtering out harmful antibodies in people with severe rheumatoid arthritis.
Heat and cold can both be used to reduce the pain and inflammation of arthritis. Patients and their doctors can determine which one works best.
Thanks to the right treatment, Shirley says his pain level today is only about 10 percent of what it once was. "Looking back on those days," he says, "it's hard to believe all the things I can do now. I've regained mobility and strength." And once again, Shirley can mow the lawn, cook meals, fix things around his house, and even pursue his favorite hobby of bird watching.
"Rheumatoid arthritis is now an illness for which newer treatments offer the real likelihood of patients being able to pursue a lifestyle without the limitations imposed by joint pain and deformity," adds Birbara.
Importance of Diet and Exercise
Arthritis experts say there's value in physical activity, the right diet, and other non-medicinal interventions that can help prevent arthritis, reduce pain, and keep people moving, as emphasized in a 10-year initiative called Healthy People 2010. A comprehensive, nationwide health promotion and disease prevention program developed by the Department of Health and Human Services, Healthy People 2010 contains 467 objectives for improving the nation's health in conditions such as cancer, sexually transmitted diseases, and arthritis.
Research in 2004, for example, demonstrated that exercise and diet together significantly improve physical function and reduce knee pain in people older than 60 who are overweight or obese, according to both the Arthritis Foundation and the American College of Rheumatology. The results of the study are published in the May 2002 issue of Arthritis & Rheumatism. Similarly, pain and disability accompanying all types of arthritis can be minimized through early diagnosis and appropriate management, including self-management, physical and occupational therapy, joint replacement surgery, weight control, and physical activity.
According to the CDC, research shows that physical activity decreases joint pain, improves function and a person's mood and outlook, and delays disability. Exercise helps reduce the pain and fatigue of many different kinds of arthritis and helps people work and do daily activities and remain independent. Range-of-motion, strengthening, and endurance exercises, such as moving a joint as far as it will go, using muscles without moving joints, and aerobic exercises, respectively, are beneficial in decreasing fatigue, strengthening muscles and bones, increasing flexibility and stamina, and improving the general sense of well-being.
It's important that people stay at their recommended weight, especially as they get older, because being overweight makes them more at risk for OA. Extra weight increases the risk for getting OA in the knees and possibly in the hips. This is especially true for women. In men, extra weight increases the risk for getting another common form of arthritis, gout (excess uric acid in the blood), as well. Maintaining a healthy weight and avoiding joint injuries reduces the risk of developing arthritis and decreases disease progression.
Some people claim to have been cured by treatment with herbs, oils, chemicals, special diets, radiation, or other products. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), however, there is no scientific evidence that such treatments cure arthritis. Moreover, some of these unproven treatments may lead to serious side effects. Patients should talk to their doctors before using any therapy that has not been prescribed or recommended by their health care team.
Juvenile Arthritis
Nearly 300,000 children in the United States have a form of juvenile arthritis or a rheumatic disease that occurs before age 16. The most common form in children is juvenile rheumatoid arthritis. The cause of most forms of juvenile arthritis remains unknown. Juvenile arthritis is not contagious, and there is no evidence that foods, toxins, allergies, or vitamin deficiencies play a role. Current research indicates that there may be a genetic predisposition to juvenile arthritis. In other words, the combination of genes a child inherits may contribute to the development of arthritis when combined with other undefined factors. Most of the symptoms of juvenile arthritis are due to inflammation as a result of imbalances in the immune system. Despite not knowing the exact cause or causes, there are many effective treatments available to help children and their parents manage juvenile arthritis. Experts say that most children with arthritis can expect to live normal lives.
The Future
Many government and private organizations are working together to carry out a plan to guide the use of the nation's resources to decrease the burden of arthritis for all Americans and increase the quality of life of those affected by arthritis. Called the "National Arthritis Action Plan: A Public Health Strategy," it provides a blueprint for reducing pain, activity limitations, and disability among people with arthritis, as well as for preventing certain types of arthritis.
As for the safety of future arthritis treatments, experience has shown that the full magnitude of some potential risks of all drugs has not always emerged during the mandatory safety and effectiveness studies conducted before the FDA can approve a drug. As always, the agency advises physicians to consider the evolving information on any medication in evaluating the risks and benefits of these drugs in individual patients.
Tratamientos biológicos de artritis
