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.
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.