Short and long term effects of Nabiximols on balance and walking assessed by 3D-gait analysis in people with Multiple Sclerosis and spasticity.

Background: Spasticity in people with Multiple Sclerosis (pwMS) is one of the most disabling symptoms on walking ability and balance. Among the systemic antispastic drugs, Nabiximols showed a good tolerability, safety profile and relevant efficacy. A few studies assessed long-term effects of this drug through clinical scales and instrumental tools, but no study investigated short-term effects. The aim of our study is to quantitatively evaluate the immediate effects of Nabiximols on walking and balance and their maintenance after 4 weeks in pwMS and spasticity. Methods: pwMS were enrolled and randomized in 2 treatment groups: Sativex (SG) and control (CG) group. All patients were assessed at T0 (before the first Sativex puff), T1(after 45 minutes) and T2 (after 4 weeks of treatment) using clinical scales and 3d-Gait Analysis . Then, the patients treated with Sativex, were divided into 5 subgroups according to Numeric Rating Scale for spasticity (NRSs) and Berg Balance Score (BBS) response: NRSs responder[1] and non-[2]; BBS responders[3] and non-[4]; NRSs-BBS responders[5]. Results: 32 pwMS (22 SG, 10 CG) were recruited. Significant improvements were found between T0 and T1 in SG compared to CG in a few clinical and kinematic parameters. Larger significant differences were found for NRSs and BBS responders' groups versus CG. Eventually, no significant differences were found comparing the results between T1 and T2, suggesting the persistence of the improvements emerged at T1. Conclusion: These results quantitatively demonstrated a short time effect of Nabiximols on balance and walking of pwMS, which is mantained after 4 weeks. Patients identified as responder by combination of NRSs and BBS showed the best efficacy. These findings may suggest how to early select the real responders in order to improve the adherence and cost-effectiveness of the therapy.