UA Study Finds Arthritis Patients Remain on Infliximab Therapy Longer than Those Treated with Etanercept
Patients with immune-mediated inflammatory disorders who are treated with infliximab (marketed as REMICADE(r)) are twice as likely to remain on therapy as those treated with etanercept (marketed as ENBREL(r)), according to new research by the Arizona Arthritis Center at the University of Arizona College of Medicine in Tucson.
Presented at the annual American College of Rheumatology (ACR) meeting, Oct. 25-29, in New Orleans, the study followed 242 patients treated with an anti-TNF (tumor necrosis factor) therapy during a four-year period at the Arizona Arthritis Center. The data found 63 percent of those treated with etanercept (61 of 96 patients) discontinued therapy compared to 28 percent (41 of 146 patients) in the infliximab group. Lack of efficacy, adverse events and patient preference were among the top reasons cited for discontinuation.
"Providing sustained clinical efficacy is essential in preventing joint destruction and restoring quality of life among patients living with these potentially debilitating diseases," said principal investigator Deborah Jane Power, DO, assistant professor of clinical medicine at the UA College of Medicine. "The ability of infliximab to provide greater long-term control may be the result of flexible dosing."
Co-investigators for the study were David E. Yocum, MD, director, Arizona Arthritis Center; Isidro Villanueva, MD, assistant research scientist, Arizona Arthritis Center; and Kathryn A. Nordensson, senior research specialist, Arizona Arthritis Center.
For nearly 20 years, the Arizona Arthritis Center has been studying the role of TNF, a chemical messenger that is involved in the inflammatory process. Over-production of TNF is believed to be involved in a variety of immune-mediated inflammatory disorders, including rheumatoid arthritis (RA) and spondyloarthropathies, such as ankylosing spondylitis and psoriatic arthritis.
The anti-TNF therapies etanercept and infliximab are administered through subcutaneous injection and infusion (intravenous injection) respectively.
The study objective was to investigate the duration of therapy for both infliximab and etanercept in a context different from clinical trials. An electronic medical record (EMR) system was used to review all patients treated with an anti-TNF therapy between February 1998 and May 2002. Complete data, including diagnosis, disease duration, dates of therapy, reason for discontinuation of the therapy, adverse events and serious adverse events, were collected.
Among those patients included in the study, 203 had rheumatoid arthritis (RA), 17 had psoriatic arthritis, 18 had juvenile RA and 4 were classified as other. Kaplan-Meier estimates for discontinuation of therapy showed the mean time on medication was 741 days with a maximum follow-up time of 1,255 days.
The mean time to discontinuation of etanercept was 533 days. Among the 61 patients who stopped etanercept therapy, 41 percent cited loss of efficacy, 36 percent cited adverse events and 3 percent cited patient preference.
The mean time to discontinuation of infliximab was 809 days. Among the 41 patients who stopped infliximab therapy, 24 percent cited loss of efficacy, 44 percent cited adverse events and 0 percent cited patient preference.
Dedicated to biomedical research into the causes and treatments of the more than 100 forms of arthritis, the Arizona Arthritis Center's internationally recognized researchers and clinical scientists are committed to understanding the ways that arthritis and bone and connective tissue diseases start and progress, in hope that individuals with arthritis can lead healthier lives.