Dosing of abobotulinumtoxinA (Dysport®) injections for adults with lower limb spasticity

Background: Spasticity is a common and frequently disabling symptom of multiple sclerosis, associated with functional impairment that can affect quality of life. Spasticity is also common in patients who have suffered stroke or traumatic brain injury (TBI). AbobotulinumtoxinA (aboBoNT-A, Dysport®) has recently received approval for the treatment of adult spasticity of any etiology.

Objectives: A phase 3, double-blind, randomized trial (NCT01249404) in hemiparetic subjects following stroke or TBI assessed the efficacy of aboBoNT-A in treating lower limb spasticity. This analysis describes aboBoNT-A doses injected in muscles that may also be involved in multiple sclerosis-related spasticity.

Methods: Subjects with hemiparesis were administered aboBoNT-A 1000U, 1500U or placebo by intramuscular injections into the soleus and gastrocnemius muscle, plus at least one additional distal muscle from the following: tibialis posterior, flexor digitorum longus, flexor digitorum brevis, flexor hallucis longus, flexor hallucis brevis.

Results: In the intent-to-treat population, Modified Ashworth Scale score mean (SD) changes from baseline to 4 weeks in the gastrocnemius soleus complex were -0.5 (0.8) for placebo, -0.6 (0.9) for aboBoNT-A 1000U (not significant versus placebo) and -0.7 (0.9) for aboBoNT-A 1500U (p=0.0091 versus placebo). Dose ranges injected per muscle for aboBoNT-A 1000U and 1500U (safety population), respectively, were: 67–200U and 0–300U, medial gastrocnemius; 67–200U and 100–300U, lateral gastrocnemius; 333–333U and 0–500U, soleus; 67–467U and 100–700U, tibialis posterior; 67–267U and 40–400U, flexor digitorum longus; 53–133U and 50–300U, flexor digitorum brevis; 53–267U and 60–300U, flexor hallucis longus; 67–133U and 50–200U, flexor hallucis brevis. Data on other muscles that may be of relevance to multiple sclerosis-related spasticity will be presented. Safety was consistent with the known profile of aboBoNT-A.

Conclusions:

The results of this phase 3 randomized study demonstrate the efficacy of aboBoNT-A in patients with lower limb spasticity. The information on dosing for lower limb spasticity in patients with stroke or TBI may be considered for dosing in patients with lower limb spasticity due to multiple sclerosis.