BACKGROUND: Clinical and MRI) measures in combination, to assess patient responses to interferon in multiple sclerosis.
OBJECTIVE: To optimize and validate a scoring system able to discriminate responses to interferon treatment in RRMSers.
METHODS: The analysis included two large, independent datasets of RRMSers who were treated with interferons that included 4-year follow-up data. The first dataset (“training set”) comprised of 373 RRMSers from a randomized clinical trial of subcutaneous interferon beta-1a. The second (“validation set”) included an observational cohort of 222 RRMSers treated with different interferons. The new scoring system, a modified version of that previously proposed by Rio et al., was first tested on the training set, then validated using the validation set. The association between disability progression and risk group, as defined by the score, was evaluated by Kaplan Meier survival curves and Cox regression, and quantified by hazard ratios (HRs).
RESULTS: The score (0-3) was based on the number of new T2 lesions (>5) and clinical relapses (0,1 or 2) during the first year of therapy. The risk of disability progression increased with higher scores. In the validation set, MSers with score of 0 showed a 3-year progression probability of 24%, while those with a score of 1 increased to 33% (HR = 1.56; p = 0.13), and those with score greater than or equal to 2 increased to 65% (HR = 4.60; p < 0.001).
CONCLUSIONS: The investigators report development of a simple, quantitative and complementary tool for predicting responses in interferon-treated MSers that could help clinicians make treatment decisions.