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| |  Study Confirms Benefits of High-Dose, High-Frequency Beta Interferon Regimen in Treatment for Multiple Sclerosis TURIN, ITALY -- July 20, 2004 -- Patients with relapsing-remitting multiple sclerosis (MS) who are treated with high-dose, high-frequency interferon beta-1b should stay on this regimen and avoid switching to low-dose, once-weekly interferon beta-1a, even in the absence of clinical or MRI signs of disease activity. This is the conclusion of an independent study published in this month's issue of the peer-reviewed Journal of the Neurological Sciences (1). Professor Luca Durelli, Chief, University Neurological Division, San Luigi Gonzaga Hospital, Torino, Italy, and principal investigator of the study, said, "These data clearly confirm the clinical benefits of high-dose, high-frequency beta interferon and demonstrate the risks to MS patients of changing to a lower-dose regimen, even when their disease appears to be in remission. These findings will further guide prescribing choices for MS patients, who sometimes question whether they can reduce the number of injections, or dosage, once their disease appears to be controlled." The interferon beta dose-reduction study is the culmination of more than five years of clinical research. Twenty-seven patients who had received interferon beta-1b 250 mcg (Betaferon®/Betaseron® for SC Injection) for three years, and were consistently free of clinical and MRI disease activity for at least two years, were randomized to either continue interferon beta-1b treatment (14 patients) or to gradually reduce their dose and change to once-weekly interferon beta-1a 30 mcg (Avonex®) for one year (13 patients). The results also showed that there were significant clinical differences between the two groups. Only 23% of those on the interferon beta-1a regimen remained free from relapses, compared with 79% of those receiving interferon beta-1b (p=0.006). Further, the relapse rate was significantly higher in those receiving interferon beta-1a (p=0.03), and the time to first relapse was significantly shorter (p=0.001). Nearly a quarter (23%) of those receiving interferon beta-1a had sustained disease progression, compared to none on interferon beta-1b. The clinical findings were confirmed by analysis of MRI scans: the number of patients without new proton density/T2 lesions was significantly higher in the group continuously treated with interferon beta-1b (77%), compared to the interferon beta-1a group (23%) (p=0.04). "At the end of the study follow-up, since disease activity resumed in most patients receiving the interferon beta-1a regimen," Prof. Durelli said "all 13 patients in the low-dose arm changed back to a high-dose, high-frequency interferon regimen. In spite of the dose and frequency of administration increase, most patients did not return to the original complete absence of disease activity (the disease stabilization they had achieved before being randomized to the low dose interferon beta-1a regimen), but kept on showing clinical or MRI activity. "Independent, head-to-head studies such as INCOMIN already confirm the superiority of high-dose, high-frequency beta interferon regimens versus lower-dose, lower-frequency regimens," added Prof. Durelli. "These newly published data show that it is vitally important for MS patients to continue to use a high-dose, high-frequency interferon regimen. About the study The study was prompted by the hypothesis that once MS is controlled for several years using a high-dose, high-frequency beta interferon regimen, it might be possible to maintain the beneficial immunological and clinical effects using lower doses or less frequent applications of beta interferon. Patients with clinical and MRI-confirmed stable disease activity on interferon beta-1b treatment for at least three years were randomized to reduce interferon beta dose and frequency of administration schedule being gradually switched to once-weekly 30 mcg interferon beta-1a and followed up for one year. Clinical and laboratory assessments were performed every three months, and an MRI scan was performed after one year. Clinical evaluation was performed on an open-label basis, MRI scans were analysed by neuroradiologists totally blinded to treatment and the patient's clinical characteristics. Clinical activity significantly worsened during the year on interferon beta-1a and although it improved during the year after returning to high-dose, high-frequency beta interferon, the MRI activity persisted in some patients, failing to return to the total absence of disease activity demonstrated after three years of chronic interferon beta-1b treatment. The impaired MRI response was not associated with occurrence of neutralizing antibodies to interferon. In conclusion, the reduction in beta interferon dose and frequency may be associated with increased signs of clinical and MRI disease activity. In addition, a return to the high-dose interferon may lead to only a partial improvement in signs of disease activity, suggesting an inherent risk in dose-reduction practices. Patients, even those with low levels of disease activity, should remain on beta interferon with a high dose and high frequency administration.
Interferon beta-1b (Betaferon® - Schering) is given on alternate days as a subcutaneous injection of 250 micrograms (8 MIU). Interferon beta-1a (Avonex(R) - Biogen) is given once weekly as an intramuscular injection of 30 micrograms (6 MIU). References: 1) Barbero P, Verdun E, Bergui M et al. High-dose, frequently administered interferon beta therapy for relapsing-remitting multiple sclerosis must be maintained over the long term: the interferon beta dose-reduction study. Journal of the Neurological Sciences 2004; 222: 13-19.
SOURCE: Prof. Luca Durelli M.D Chief
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