An observational comparison of natalizumab vs. fingolimod using JCV serology to determine therapy

Background: The lack of prospective trial data comparing certain multiple sclerosis (MS) therapies could be addressed with observational research. Objective: The objective of this paper is to investigate outcomes of natalizumab versus fingolimod treatment in an MS cohort using a novel method of patient selection. Methods: We reviewed entries from our clinic's database for all relapsing-remitting MS patients started on fingolimod and natalizumab where JCV serology was used to determine treatment. We analyzed each group for time to first relapse and in a second analysis, time to first relapse or gadolinium-enhancing lesion. Results: Sixty-nine patients on natalizumab and 36 on fingolimod met our inclusion criteria and had adequate follow-up for analysis. The baseline clinical characteristics at the time of treatment switch were similar. With a mean follow-up of 1.5 years for both treatment groups, there was a trend favoring natalizumab in time to first relapse, although this was not statistically significant (2.20 (0.87, 5.55) p = 0.095). There was a significant difference in the secondary outcome, time to relapse or gadolinium-enhancing lesion (2.31 (1.03, 5.17) p = 0.041), favoring natalizumab. Adjusted analyses favored natalizumab for both outcomes (p < 0.05). Conclusion: This work employed an observational study design where treatment allocation by JCV serology allowed for treatment groups with well-balanced characteristics.