Drug shows promise against arthritis common in people with psoriasis
Patients who responded to brodalumab had a significant improvement in their skin and reduction in the swelling of the fingers and toes, a condition called dactylitis that is common in psoriatic arthritis, according to the study's lead researcher, Dr. Philip Mease, a rheumatologist at Swedish Medical Center in Seattle.
"We have a medication with a different mechanism of action than currently available drugs, increasing our chances to control this disease, which can be disabling and significantly affects patients' function and quality of life," said Mease.
"We know that many patients will lose response to some medications or develop adverse effects, so there is a need for medicines that work differently," he said. "We have a chance to bring patients back closer toward their normal state of being."
The study was funded by Amgen, the maker of brodalumab. Results of the study were published June 12 in the New England Journal of Medicine. The study's findings were also scheduled to be presented on Thursday at the European Congress of Rheumatology's annual meeting in Paris.
Psoriatic arthritis is a type of arthritic inflammation that affects as many as 30 percent of people who have psoriasis, according to background information in the study.
Psoriasis causes scaly red and white patches on the skin, according to the American College of Rheumatology (ACR). In psoriatic arthritis, the immune system attacks the joints as well, causing inflammation. Persistent inflammation from psoriatic arthritis can lead to joint damage, according to the ACR.
Like psoriasis, psoriatic arthritis symptoms come and go, vary from person to person, and even change locations over time.
Psoriatic arthritis may affect one joint or several. For example, it may affect one or both knees. Affected fingers and toes can become swollen. Fingernails and toenails also may be affected.
Mease noted that psoriatic arthritis has a genetic component that makes it distinct from other types of arthritis.
"There are also certain genes that are present in people who develop the arthritis that are not present in people with psoriasis. So there seems to be a heavy genetic component for determining who gets psoriasis and goes on to get psoriatic arthritis," he said.
Current treatment for psoriatic arthritis depends on how much pain the patient has. Treatment usually starts with painkillers such as ibuprofen (Motrin or Advil) or naproxen (Aleve).
Mease noted that many patients are also given methotrexate (Trexall), which treats both arthritis and psoriasis. Other drugs, known as biologic therapy, that are also used to treat both conditions include adalimumab (Humira), etanercept (Enbrel), golimumab (Simponi) and infliximab (Remicade).
Current drugs such as methotrexate target a substance called tumor necrosis factor-alpha, which is produced in response to inflammation. But these drugs tend to be less effective over time, Mease said.
Brodalumab works differently. It acts against interleukin-17 receptor A, a substance found in higher levels in people with psoriatic arthritis, according to the study.
For the current phase 2 trial of brodalumab, Mease and colleagues randomly assigned 168 patients with psoriatic arthritis to a low (140 milligrams) or high dose (280 milligrams) of brodalumab, or a placebo.
The average age of the study participant was 52 years. Two-thirds of the study volunteers were women and 94 percent were white (which included Hispanics and Latinos). The average amount of time they'd had psoriatic arthritis was nine years, according to the study.
After 12 weeks, patients taking either dose of brodalumab had a greater response to treatment than those receiving placebo (37 percent and 39 percent versus 18 percent).
Moreover, 14 percent of those taking brodalumab had a 50 percent improvement in symptoms based on the American College of Rheumatology response criteria, compared with 4 percent who received the placebo, the researchers found.
Improvements were seen in both patients who had previous biologic therapy, as well as those who had not had biologic therapy in the past, the researchers noted.
After 24 weeks of treatment, 51 percent of patients taking the lower dose of brodalumab and 64 percent taking the higher dose responded to the drug. In addition, 44 percent of the patients who switched from placebo to brodalumab responded to treatment.
These responses were maintained through a year, the researchers said.
At week 12, serious side effects occurred in 3 percent of patients in the brodalumab groups and in 2 percent of those in the placebo group, they add. These included stomach pain and a skin infection called cellulitis. "This is consistent with what had been seen with other so-called biologic medications," Mease said.
Dr. Robert Kirsner is a professor and vice chairman of the department of dermatology and cutaneous surgery at the University of Miami Miller School of Medicine. "The results of this, albeit small study are extremely encouraging for patients who suffer from these conditions and for the physicians who treat them," Kirsner, who was not part of the study, said.
A phase 3 trial—the last step before potential U.S. Food and Drug Administration approval—is under way, testing brodalumab as a treatment for psoriasis. According to Mease, Amgen hopes to have the drug approved for psoriasis first, and then as a treatment for psoriatic arthritis.
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