Systematic Literature Review of AbobotulinumtoxinA in Clinical Trials for Blepharospasm and Hemifacial Spasm

BACKGROUND The aim was to elucidate clinical trial efficacy, safety, and dosing practices of abobotulinumtoxinA (ABO) treatment in adult patients with blepharospasm and hemifacial spasm. To date, most literature reviews for blepharospasm and hemifacial spasm have examined the effectiveness of all botulinum neurotoxin type A products as a class. However, differences in dosing units and recommended schemes provide a clear rationale for reviewing each product separately. METHODS A systematic literature review was performed to identify randomized controlled trials and other comparative clinical studies of ABO in the treatment of blepharospasm and hemifacial spasm published in English between January 1991 and March 2015. Medical literature databases (PubMed, Cochrane library, EMBASE) were searched. A total of five primary publications that evaluated ABO for the management of blepharospasm and hemifacial spasm were identified and summarized. RESULTS Data included 374 subjects with blepharospasm and 172 subjects with hemifacial spasm treated with ABO. Total ABO doses ranged between 80 and 340 U for blepharospasm and 25 and 85 U for hemifacial spasm, depending on the severity of the clinical condition. All studies showed statistically significant benefits for the treatment of blepharospasm and hemifacial spasm. ABO was generally well tolerated across the individual studies. Adverse events considered to be associated with ABO treatment included: ptosis, tearing, blurred vision, double vision, dry eyes, and facial weakness. DISCUSSION These data from 5 randomized clinical studies represents the available evidence base of ABO in blepharospasm and hemifacial spasm. Future studies in this area will add to this evidence base.