By Thomas S. May
RHODES, GREECE -- June 19, 2007 -- Magnetic resonance imaging (MRI) of brain lesions at the beginning and after one year of treatment with Interferon beta (IFN-b) can help identify patients with multiple sclerosis (MS) who do not respond to IFN-b treatment, according to a study presented here at the 17th Meeting of the European Neurological Society (ENS).
"Early identification of nonresponders may help neurologists in their decision about MS treatment," said Carlo Pozzilli, MD, Multiple Sclerosis Centre, S. Andrea Hospital, Rome, Italy. Dr. Pozzilli is head of the research team that performed the retrospective, post-marketing study involving 345 patients (101 men and 244 women, mean age at baseline 32.9±9.1 years) who had been treated with IFN-b for an average of 4.5 years (median 4, range 2-13). At the beginning of the study, subjects had a mean disease duration of 5.5±4.9 years and a median Expanded Disability Status Scale (EDSS) score of 1.5 (range 0-4.5).
The researchers analysed EDSS scores and MRI scans taken at baseline and after one year of IFN-b treatment of all patients who completed the study. For subjects who discontinued IFN-b therapy, the final EDSS score was calculated at the last neurological assessment during IFN-b treatment.
Patients with an increase of at least 1 point on the EDSS score (confirmed in two consecutive visits separated by a 6-month interval) were considered to have a "poor clinical response." Disease activity was determined based on the presence of gandolinium-enhancing (Gd-enhancing) lesions in post-contrast T1-weighted scans and on the accumulation of hyperintense lesions on T2-weighted images.
Patients with a longer disease duration at the beginning of IFN-b treatment and a higher baseline EDSS than those with a stable level of disability were also more likely to have a poor response to IFN-b therapy (P =.04 and P <.001, respectively). A relapse within the first year of IFN-b therapy also was associated with an increased likelihood of poor response over the study period (OR 2, 95% CI 1.3-3.4; P =.003)
The investigators found, however, that MRI data were even stronger predictors of long-term outcome, whereby both the presence of at least one Gd-enhancing lesion at 1-year (OR 3.4, 95% CI 2-5.7; P <.001) and an increase in T2 lesion burden (OR 8.6, 95% CI 5-14.5; P <.001) were related to a poor outcome.
According to Dr. Pozzilli, "these results underline the importance of performing an MRI scan at the end of the first year of treatment with Interferon beta, in order to identify patients who do not respond to treatment."
[Presentation title: Early Predictors of Poor Response to Interferon Beta Therapy in a Cohort of Relapsing-remitting Multiple Sclerosis. Abstract P294]
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