A new type of medication being studied and used for the treatment of psoriasis and psoriatic arthritis is called a biologic agent because of the way they are synthesized and the fact that they are proteins. The significant advances in understanding the causes of psoriasis and psoriatic arthritis have resulted in the development of this new class of medications. The biologic drugs target the abnormality in the immune system to modify the biology of the person with psoriasis or psoriatic arthritis back to normal.
As discussed, tumor necrosis factor-alpha (TNF-alpha) is one of many inflammatory messengers that can cause the tender; swollen joints of psoriatic arthritis and the red, scaly, raised areas of skin in psoriasis. TNF-alpha is increased in the skin and joints of patients with psoriasis and psoriatic arthritis. When TNF-alpha is increased, it causes a number of changes in the blood vessels, skin, and joints, which can result in inflammation in the skin and joints. Reducing the activated T-cells that cause the release of TNF-alpha or blocking this inflammatory messenger can reduce inflammation (redness and swelling) of the joints and improve the skin lesions of psoriasis.
 |
| Psoriasis Treatment Cure |
Currently, three biologic agents that block TNF-alpha are being used in psoriatic arthritis: infliximab, etanercept, and adalimumab. These agents are able to neutralize the undesirable inflammatory effects by controlling the amount of TNF-alpha in the skin and joints.
In addition, alefacept, a biologic agent that can reduce the number of T-cells that cause the release of TNF-alpha, has been recently studied in psoriatic arthritis and found to be effective. These two biologic agents are explained in more detail. Here, I will briefly outline the experience with these agents in psoriatic arthritis.
lnfliximab
- Infliximab targets and blocks the inflammatory messenger TNF-alpha by binding to it.
- Infliximab acts like a sponge to take TNF-alpha out of circulation.
- The drug is given by intravenous infusion over approximately a two-hour period.
- lnfliximab has also been used to treat rheumatoid arthritis and Crohn's disease (an inflammatory disease of the bowel).
- lnfliximab has undergone recent clinical testing in psoriatic arthritis, but is not yet approved in Canada for psoriatic arthritis.
- A clinical study, the Infliximab Multinational Psoriatic Arthritis Controlled Trial (IMPACT), recently reported that about 70 percent of patients had an improvement as measured by a clinical score (ACR-20), over a sixteen-week study. In addition, 67 percent had an excellent improvement in the psoriasis.
- Etanercept targets and blocks the inflammatory messenger TNF-alpha in a different way than infliximab.
- Etanercept is a fully human receptor that circulates in the blood and acts like a sponge to take TNF-alpha out of circulation. Etanercept binds to TNF-alpha, preventing TNF-alpha from both binding to the inflammatory cell and sending it a faulty message. By blocking this faulty message, inflammation is reduced.
- Etanercept is self-administered by patients in one of two ways:
1. Once weekly: Two injections under the skin (subcutaneous) of 25 milligrams each on the same day.
2. Twice weekly: One injection under the skin (subcutaneous) of 25 milligrams three to four days apart. - Etanercept has been extensively studied in psoriatic arthritis in well-designed, randomized, controlled trials.
- In one recent study, etanercept was given to 205 patients with psoriatic arthritis. Patients were given one injection (25 milligrams) of etanercept or placebo under the skin (subcutaneous), twice weekly over twenty-four weeks. A rapid and significant improvement was reported in 59 percent of patients receiving etanercept using the measured score (ACR-20). Significant improvements in skin lesions were also reported by 57 percent of patients.
- Etanercept has been studied alone and in combination with other treatments such as methotrexate and other NSAIDs.
- Etanercept is currently approved in the United States and Canada for the treatment of psoriatic arthritis.
Adalimumab
- Adalimumab blocks tumor necrosis factor-alpha (TNF-alpha) by binding to it.
- Adalimumab is administered as an injection every other week.
- Adalimumab works quickly (many patients notice an improvement within the first month).
- Studies have shown an excellent improvement in psoriasis and psoriatic arthritis.
- Adalimumab has also been used in combination with other types of treatment, such as methotrexate, NSAIDs, or SAARDs in the treatment of psoriatic arthritis.
- The most common side effects include reaction at the injection site, cold, headache, and flu-like symptoms.
Alefacept
- Alefacept blocks the activation of T-cells and reduces the number of activated T-cells that contribute to the release of inflammatory mediators.
- It is administered by intramuscular iniection.
- Alefacept has undergone recent clinical trial evaluation in psoriatic arthritis, but is not yet approved for use in psoriatic arthritis in Canada. A recent clinical study using alefacept and methotrexate resulted in significant improvement in patients with psoriatic arthritis.
 |
| Psoriasis Treatment Cure |
Ustekinumab (Stelera)
- Ustekinumab targets and blocks chemical messengers (cytokines), interleukin-12, and interleukin-23.
- Ustekinumab has been used in a recent study in patients with psoriatic arthritis and has been found to improve psoriatic arthritis.
- Clinical trials are currently ongoing to establish the effectiveness of this medication in the treatment of psoriatic arthritis.