Fampridine response in MS patients with gait impairment in a real-world setting: Need for new response criteria?

Objective: The primary objective of this real-world study was to describe the response to fampridine and changes of gait parameters in multiple sclerosis (MS) patients' walking disability (Expanded Disability Status Scale (EDSS): 4-7) after treatment with fampridine for 2weeks as recommended by the European Medicines Agency (EMA) and compare it with the overall physician's judgement. Methods: A total of 211 adult MS patients were analyzed using a multimodal gait assessment including the timed 25-foot walk test (T25FW), 2-minute walking test (2-MWT), 12-item Multiple Sclerosis Walking Scale (MSWS-12), the GAITRite electronic walkway system, and the patients' clinical global impression (CGI). Multimodal gait assessment was compared with the clinician's impression of overall improvement after 2weeks. Results: In total, 189 subjects were included, of which 133 (70.37%) were responders to fampridine (RF), according to physician's judgement. Looking at independent multimodal gait assessment, RFs showed improvement of 12.60% in the T25FW, 19.25% in the 2-MWT, 21.12% in the MSWS-12, and 6.54% in their Functional Ambulation Profile (FAP) score. The combination of the T25FW and the MSWS-12 would offer the best sensitivity and specificity for determining response to fampridine according to both neurologists' and patients' classification. Conclusion: This study provides new information on the use of fampridine in a real-world setting with a large patient sample on the potential benefit of using more definitive responder criteria to fampridine for the clinical setting.