IncobotulinumtoxinA: A Review in Upper Limb Spasticity

Intramuscular incobotulinumtoxinA (Xeomin(®)) is indicated for the treatment or improvement of adult patients with upper limb spasticity (featured indication), cervical dystonia, blepharospasm and glabellar lines. It is a highly purified formulation of botulinum toxin type A that inhibits acetylcholine signalling at neuromuscular junctions, reducing muscle hypertonia. This narrative review discusses the clinical use of incobotulinumtoxinA in adults with upper limb spasticity and summarizes its pharmacological properties. In single-treatment phase 3 trials, compared with placebo, incobotulinumtoxinA treatment improved muscle tone, global spasticity, functional spasticity-related disability and some aspects of carer burden in adults with upper limb spasticity. These beneficial effects of incobotulinumtoxinA on muscle tone were generally maintained in extension studies, in which up to five additional incobotulinumtoxinA treatments were administered. Functional spasticity-related disability and carer burden were also reduced during longer-term incobotulinumtoxinA treatment. IncobotulinumtoxinA was generally well tolerated in clinical trials, with relatively few patients experiencing treatment-related adverse events, most of which were of mild to moderate intensity. No neutralizing antibodies that would potentially cause secondary nonresponse against incobotulinumtoxinA were detected after single and multiple treatments in these trials or in phase 3 and 4 trials of incobotulinumtoxinA in other indications, which may be an advantage of this purified formulation. Further research would help to more fully determine the impact of neurotoxin purification in terms of reducing the potential risk of immunogenic responses during long-term treatment. Hence, incobotulinumtoxinA is a useful treatment option for upper limb spasticity in adult patients.