Medical Author: William C. Shiel Jr., MD, FACP, FACR
Medical Editor: Leslie J. Schoenfield, MD, PhD
A new drug is available for adult patients with moderate to severe rheumatoid arthritis who have not responded to other disease modifying antirheumatic drugs (DMARDs)! The brand name of the new drug is Kineret and its generic name is anakinra.
This is big news in the treatment of rheumatoid arthritis. You see, anakinra (Kineret) is a new type of biological response modifier (BRM) for treating this disease. Thus, anakinra (Kineret) acts by blocking the biological effects of the chemical messenger, Interleukin-1 (IL-1). IL-1 is a protein that is produced by many cells in the body. It is found, however, in increased amounts within joints that are inflamed by rheumatoid arthritis. In fact, IL-1 promotes the inflammation and destruction of cartilage and bone in rheumatoid arthritis. Accordingly, this BRM, like the traditional DMARDS, can prevent progressive joint destruction.
What are advantages of Kineret?
- Anakinra (Kineret) may be used alone or in combination with methotrexate (Rheumatrex) or other DMARDs.
- To date, no cases of the activation of tuberculosis or other opportunistic infections (such as serious fungus infections) have been reported with the use of anakinra (Kineret). In contrast, opportunistic infections have been reported with another type of BRM drugs that includes infliximab (Remicade) and etanercept (Enbrel). (These biological response modifiers work by blocking another of the body's promoters of joint inflammation called tumor necrosis factor, TNF).
- Patients can become intimately involved in their own treatment by self-injecting anakinra (Kineret) under the skin.
- Patients will have the option of self-injecting 100 mg prefilled syringes or loading these into a specially designed injector device, called the Simpleject™.
What are disadvantages of Kineret?
- Anakinra (Kineret) must be injected into the skin daily.
- The primary adverse event noted in clinical trials was local skin irritation at the injection site. Other infrequent side effects included mild reductions in white blood cell counts, headache, and an increase in respiratory infections.
- Low white blood cell counts have been reported when anakinra (Kineret) is combined with the TNF-blocking drugs (infliximab and etanercept). Moreover, when combined with the TNF-blockers, anakinra (Kineret) was associated with a significant increase in serious infections. (White blood cells help fight infections.)
- Patients are advised to keep anakinra (Kineret) refrigerated at 2-8 degrees C (36-48 degrees F) until planned use at room temperature.
Dr. Shiel's perspective
Anakinra (Kineret) is an effective and relatively safe drug that has been studied in thousands of rheumatoid arthritis patients to date. While no data exists that directly compares anakinra (Kineret) with other agents in treating rheumatoid arthritis, it appears that the effectiveness rates of this drug in studies to date are comparable to existing DMARDs and biologic drugs. Furthermore, the Simpleject™ system of administration is relatively easy to use, even for patients with significant hand deformity.
So, which rheumatoid arthritis patients should receive this drug? First of all, I will offer anakinra (Kineret) to patients who have not responded to other disease modifying antirheumatic drugs (DMARDs). Thus, I will consider anakinra (Kineret) for patients who have not responded to traditional DMARDs, or do not want to use intravenous treatment with infliximab (Remicade), or cannot get etanercept (Enbrel) because of lack of insurance coverage. I will certainly also consider anakinra (Kineret) for patients with moderate to severe rheumatoid arthritis who have failed infliximab (Remicade) or etanercept (Enbrel).
Anakinra (Kineret) might be considered in patients with rheumatoid arthritis who have experienced a serious reaction (side effect) to another BRM agent (infliximab/Remicade or etanercept/Enbrel). Also, be aware that aggravation of congestive heart failure has been reported to be associated with infliximab usage. Therefore, anakinra (Kineret) may be an option for rheumatoid arthritis patients who have known significant heart disease. Finally, I personally will not prescribe anakinra (Kineret) together with the TNF-blocking drugs until more information is available to verify the safety of this combination.
It is noteworthy that at our recent national meeting of arthritis experts, the American College of Rheumatology, anakinra (Kineret) was shown to improve the functional status (ability to perform various physical activities) of patients with rheumatoid arthritis. In another study, anakinra (Kineret) was demonstrated to significantly improve the number of productive days at work and domestic home activity in patients with rheumatoid arthritis. This is important information because, after all, these are ultimately critical measures of successful treatment.
For more information, please read the Kineret drug monograph.