Investigators taking part in the largest retrospective, observational study of multiple sclerosis recently released new findings relative to long-term treatment for the disease.1
Scrutinizing Long-Term Therapy
Investigators from several medical and research centers presented the findings at the annual meeting of the European Neurological Society in Vienna. The study, which is still ongoing, is labeled Quality Assessment in MS Therapy, or QUASIMS.
"The results of the QUASIMS study are crucial in advancing our understanding of how to best manage relapsing-remitting MS over the long term," said Volker Limmroth, MD, PhD, in the department of Neurology at University Hospital Essen in Essen, Germany, and the study's principal investigator.
"The goal of this study was to compare the efficacy of interferon-beta products in relapsing MS in different clinical settings throughout the world," Limmoth and his fellow investigators wrote.
Patients were included in the study if they had been taking one of four interferon betas uninterrupted for at least two years. That included 30 micrograms (mcg) of Avonex (interferon beta-1a) once per week, 250 mcg of Betaseron (interferon beta-1b) once every other day, or two different doses of Rebif (interferon beta-1a): 22 mcg or 44 mcg three times per week.
Other patients were assigned to a follow-up group if they had been taking therapy for less than two years, then were subsequently prescribed one of four available interferon betas uninterrupted for two years.
The study investigators measured treatment outcome based on each person's disability at end of the two-year period, as well as those who wound up being relapse-free during that time.
Similar Treatment Effectiveness Found
More than 7100 patients have been participating in the study. The investigators found minimal changes in the patients' disability, on average, after two years of therapy. The percentage of patients who became relapse-free after two years of therapy was about 48 percent in the group taking Avonex, approximately 46 percent in the group taking Betaseron, and about 44 percent and approximately 38 percent in the groups taking the 22-microgram and 44-microgram doses of Rebif, respectively.
In the follow-up group, the percentage of relapse-free patients after two years of therapy ranged from 36 percent for those taking Avonex to about 34 percent for those in the Rebif group.
"Efficacy was similar among patients treated with the four different interferon-beta preparations in different countries," the researchers wrote. "Switching between different interferon preparations did not appear to provide additional benefits."
Interferon beta preparations are widely used as first-line therapy for people with relapsing-remitting multiple sclerosis, experts say. In clinical studies, they have been shown to reduce relapse rates and delay the disease's progression by approximately a third.2,3
"These results suggest that higher doses and frequencies of interferon beta may not necessarily be better when you take into account … that patients treated with Avonex could have significant advantages in the long term due to the treatment's low incidence of neutralizing antibodies and its once-weekly dosing, which encourages better long term adherence to therapy," Limmroth said.
1. Limmroth V, Werneck LC, Nagels G, Lugaresi A, Kalski G, Wernsdoerfer C. QUASIMS: a worldwide comparative study of interferon-beta products for relapsing multiple sclerosis. 15th Annual Meeting of the European Neurological Society. 2005 June 18-June 22. Vienna, Austria.
2. Interferon beta-1b in the treatment of multiple sclerosis: final outcome of the randomized controlled trial. The IFNB Multiple Sclerosis Study Group and The University of British Columbia MS/MRI Analysis Group. Neurology 1995 Jul;45(7):1277-85.
3. Jacobs LD, Cookfair DL, Rudick RA et al. Intramuscular interferon beta-1a for disease progression in relapsing multiple sclerosis. The Multiple Sclerosis Collaborative Research Group (MSCRG). Ann Neurol 1996 Mar;39(3):285-94.
John Martin is a long-time health journalist and an editor for Priority Healthcare. His credits include overseeing health news coverage for the website of Fox Television's The Health Network, and articles for the New York Post and other consumer and trade publications.
