Review of available data for the efficacy and effectiveness of nabiximols oromucosal spray (Sativex) in multiple sclerosis patients with moderate to severe spasticity

Background: Sativex (USAN: nabiximols) oromucosal spray is indicated for treatment of multiple sclerosis (MS) patients with moderate to severe spasticity and inadequate response to other antispasticity medications who demonstrate clinically significant improvement during an initial trial of therapy. This narrative review investigated the efficacy and effectiveness of nabiximols oromucosal spray for moderate to severe MS spasticity by examining spasticity 010 Numerical Rating Scale (NRS) data from interventional and observational studies which featured a 4-week trial period as per the European Union approved label. Summary: Across both study types, clinically relevant and statistically significant reductions in mean MS spasticity 0-10 NRS scores were measured soon after treatment start and were maintained in the mid to long term in treatment responders. Initial responder rates (≥ 20% NRS improvement from baseline at week 4) ranged from 47.6% to 81.4%, tending lower in the randomized clinical trials setting. Clinically relevant responder rates (≥ 30% NRS improvement from baseline at week 12) were similar between study types (range 3041%) except for one outlier (74% in an observational study). Two open studies reported treatment continuation for ≥ 18 months in approximately half of patients who initiated treatment. In most longer-term studies, symptomatic improvement in MS spasticity was maintained at mean daily dosages of about 67 sprays/day. Safety was consistent with the known profile of nabiximols. Key messages: Experimental and observational studies of nabiximols oromucosal spray recorded similar findings. About half to two-thirds of MS patients who begin treatment will perceive initial symptomatic relief of spasticity within the 4-week trial period. About 40% of patients who initiate treatment will reach the ≥ 30% NRS improvement threshold at 3 months, comprising the majority of patients who continue long-term treatment. A trial of therapy with nabiximols is useful to identify patients most likely to gain longer-term improvement in spasticity symptoms and discontinue those with insufficient benefit.