Objectives: To investigate if MS subjects treated with PRF 10mg BID will show a greater benefit from active enabled motor training compared with placebo. Methods: Single center, phase 4, pilot, placebo-controlled, double-blind 18 weeks study. Fifteen patients were randomized to receive PRF 10 mg BID and fifteen to received placebo BID. All patients participated in active enabled motor training of 3 sessions of 1 hour/week for 6 weeks. Patients were evaluated at -4, 0, 6 and 14 weeks using the timed 8 meters walk (8 MW), the 6 minute walk (6 MW) and the timed sit to stand (STS). Results: The PRF treated group achieved a higher mean percent improvement from baseline in all tasks at both 6 and 14 week time points. The difference reached statistical significance (mean difference of 14.29, p=0.046) for the 8MW at the 14 week time point. A higher incidence of responders (>20% improvement from baseline) was seen in the PRF treated group at 6 weeks on the 8MW (odds ratio [OR] of 2.31) and the 6MW (OR of 1.63), and at 14 weeks on the 8MW and the STS (OR of 2.0). Conclusions: PRF in MS patients appears to enhance the benefit of active enabled motor training and to better sustain it over the following 8 weeks.