(RxWiki News) Rheumatoid arthritis and psoriatic arthritis share many characteristics. While a certain class of medications — called anti-TNFs — has been shown to be a helpful treatment for rheumatoid arthritis, it remains unclear how well they work for patients with psoriatic arthritis.
No cure exists for psoriatic arthritis. So treatment focuses on controlling inflammation in the joints. Anti-TNF medications have been shown in the past to be effective for psoriatic arthritis on a short-term basis. According to the researchers, this study supports the long-term effectiveness of anti-TNF medications for psoriatic arthritis.
"Ask your doctor about available clinical trials for your condition."
Arthur Kavanaugh, MD, of the University of California, San Diego, and colleagues conducted this study.
The study was an open-label (where researchers and clinical trial participants know which treatment is being given) extension study of a six-month randomized trial in which 405 people with psoriatic arthritis were give a placebo (fake medication) or 50 to 100 milligrams of golimumab every four weeks.
After four months, patients with less than 10 percent improvement in their number of tender and swollen joints were given the medication. After six months, all participants still on the placebo began taking 50 milligrams of golimumab.
About 60 percent of patients were men, and nearly all were white. The average age was 47 and average disease duration was 7.5 years. None of the patients were previously treated with an anti-TNF medication. Half were on methotrexate (a common medication used to treat psoriatic arthritis) with an average dose of 15 milligrams per week.
After taking golimumab for two years, 63 percent to 70 percent of patients reported 20 percent improvement in American College of Rheumatology (ACR) response criteria.
ACR criteria are used to measure improvement in tender and swollen joint counts and other measures of disease activity in patients with diseases like rheumatoid arthritis and psoriatic arthritis. ACR20 is a score that indicates an arthritis patient has had 20 percent improvement in the number of tender or swollen joints and 20 percent improvement in three of five other criteria.
Similarly, ACR50 signals 50 percent improvement, and ACR70 signals 70 percent improvement.
Also, 72.2 percent to 85.2 percent of patients saw 50 percent improvement on the Psoriasis Area and Severity Index (a widely used tool which measures the severity of psoriasis).
After two years, 46 percent of those initially receiving the placebo and then given the TNF inhibitor reported 50 percent improvement in ACR response criteria. Those taking the 50 milligram dose or who increased it to 100 milligrams had 46.6 percent improvements in ACR response criteria. Those on 100 milligrams had a 51.4 percent improvement in ACR criteria.
Across the dose groups, improvements of 70 percent were seen in 31 percent to 35.6 percent of patients.
Patients who started on 50 milligrams and increased to 100 milligrams saw limited benefits.
The most common side effects were upper respiratory tract infections. A total of 6 percent of patients withdrew from the study due to negative side effects. Serious side effects occurred in 6.5 percent of the 50 milligram group and 8 percent of the 100 milligram group.
The authors of this study noted that the lack of a placebo group limited their analysis of the results. But they said that they avoided keeping patients on a placebo for too long since disease-associated damage can come from being on a placebo long term when one has a condition like psoriatic arthritis.
This study was published in the November issue of the Annals of the Rheumatic Diseases.
Simponi is manufactured by Janssen. This research was supported by Janssen and Merck/Schering-Plough. Several investigators were employees of Janssen.
Investigators reported financial ties with various companies, including Janssen, Merck/Schering Plough, Abbott, Bristol-Myers Squibb, Genentech, Genzyme, UCB, Amgen and Pfizer.