Trial to Evaluate the Effect of Nabiximols Oromucosal Spray on Clinical Measures of Spasticity in Participants With Multiple Sclerosis

This study will be conducted to evaluate the effect of multiple doses of nabiximols as adjunctive therapy compared with placebo on a clinical measure of velocity-dependent muscle tone in the lower limbs (Modified Ashworth Scale Lower Limb Muscle Tone-6 \[MAS LLMT-6\]) in participants with multiple sclerosis (MS) who have not achieved adequate relief from spasticity with other antispasticity medications.

Each period of this multicenter, randomized, double-blind, placebo-controlled, 2-treatment, 2-period, crossover trial includes a 7-day Baseline period, a 3-week treatment period (comprising a 2-week titration phase and a 1-week maintenance phase). Eligible participants will enter the 7-day baseline period of each treatment period. During baseline, participants will maintain their optimized oral MS antispasticity medication regimen and record their 11-point NRS spasticity score and spasm count using an electronic daily diary. On Day 1, eligible participants will be randomized to 1 of 2 treatment sequences, each composed of 2 treatment periods, with administration of multiple doses of nabiximols or placebo in a 1:1 ratio. Participants will be advised to titrate the investigational medicinal product (IMP), beginning with 1 spray/day, to an optimized dose or to a maximum of 12 sprays/day over the first 14 days of treatment. Participants should continue at the same dose level achieved at the end of the titration phase ±1 spray divided into a morning dose and an evening dose for the remainder of the treatment period. Lower limb muscle tone, health-related quality of life, safety, tolerability, and pharmacokinetics will be evaluated during the treatment period. Participants who complete the trial will participate for a maximum of 90 days, which consists of a maximum 29-day screening period and a maximum 61-day treatment period (s), including washout between periods, and safety follow-up.