Research zeroes in on psoriatic arthritis
From January/February 2005 Psoriasis Advance
The American College of Rheumatology 2004 Annual
Scientific Meeting was held in October in San Antonio, Texas. The conference is an annual event that attracts thousands of international medical professionals, and organization and company representatives.
In a conference sponsored by Centocor, Inc., international
researchers and physicians lined the walls of the room to hear about arthritis research on psoriatic arthritis and ankylosing spondylitis in comparison to rheumatoid arthritis.
"We're learning about how these diseases are very similar," said Philip Mease, M.D., clinical professor of rheumatology, Seattle Rheumatology Associates, Seattle, Wash. "There are a lot of similarities in the chemical players and cytokines between rheumatoid arthritis and psoriatic arthritis," said Dr. Mease, such as the prominent role of TNF-alpha.
However, psoriatic arthritis differs from rheumatoid arthritis, Mease emphasized, in the chemicals that lead to inflammation in the synovium, a thin membrane in freely moving joints that lines the joint capsule and secretes fluid to protect the joint.
Psoriatic arthritis also differs because the initial pathology (beginning of the disease) is in the enthesis rather than in the synovium. The enthesis is where the tendons, ligaments
and connective tissue (fascia) inflame where they connect to the bone. In certain cases, this inflammation may lead to calcification at the insertion site. The most commonly affected areas are the heels where the Achilles tendon and the plantar fascia insert. This can lead to pain when standing or walking.
International researchers have acknowledged these differences by forming an organization known as GRAPPA, the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis. GRAPPA is working to define the tools used in measuring psoriatic arthritis treatment success, including outcome measures and international treatment guidelines. They are "not just looking at treating arthritis, but also the spine, dactylitis (enlargement of the toes and fingers) and skin," said Dr. Mease.
The effort and excitement surrounding psoriatic arthritis research bodes well for the community, leading to encouraging news about treatment options and more accurate assessment scores.
Two new treatments for psoriatic arthritis show significant improvement
Remicade (generic name infliximab) was shown to improve psoriatic joint and skin symptoms in a double-blind, placebo-controlled study of 200 patients.
Measuring arthritis measurement scores by week 14 in those using 5 milligrams/kilogram of infliximab:
- About 60 percent achieved 20 percent improvement
- Almost one half achieved 50 percent improvement
- Nearly one third achieved 70 percent improvement
About half of the patients studied were also using methotrexate, which did not significantly affect the improvement level. More than 60 percent of those using infliximab
achieved 75 percent improvement of their psoriasis severity score by week 14. Remicade is manufactured by Centocor, Inc.
Humira, also known as adalimumab, was studied for 24 weeks in 289 psoriatic arthritis adult patients.
Patients gave themselves 40 mg of adalimumab self-administered every other week by subcutaneous (under the skin) injections.
- Nearly one quarter of the patients (23 percent) achieved 70 percent improvement in their arthritis measurement score.
- Nearly 40 percent (39 percent) achieved 50 percent improvement in the measurement score.
- More than half (57 percent) achieved a 20 percent improvement in the measurement score.
Response was rapid, with 27 percent and 52 percent of patients achieving 20 percent improvement in their arthritis measurement scores after two and four weeks, respectively. Measurements of skin also improved significantly during the psoriatic arthritis trial, with 75 percent of patients improving their severity scores by half, nearly 60 percent by 75 and more than 40 percent by 90. Humira is manufactured by Abbott Laboratories.
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