Long-term efficacy of botulinum toxin A for treatment of blepharospasm, hemifacial spasm, and spastic entropion: a multicentre study using two drug-dose escalation indexes

Purpose To investigate the long-term effectiveness and safety of botulinum neurotoxin A (BoNT-A) treatment in patients with blepharospasm (BEB), hemifacial spasm (HFS), and entropion (EN) and to use for the first time two modified indexes, 'botulin toxin escalation index-U' (BEI-U) and 'botulin toxin escalation index percentage' (BEI-%), in the dose-escalation evaluation. Methods All patients in this multicentre study were followed for at least 10 years and main outcomes were clinical efficacy, duration of relief, BEI-U and BEI-%, and frequency of adverse events. Results BEB, HFS, and EN patients received a mean BoNT-A dose with a significant inter-group difference (P < 0.0005, respectively). The mean (+/- SD) effect duration was statistically different (P = 0.009) among three patient groups. Regarding the BoNT-A escalation indexes, the mean (+/- SD) values of BEI-U and BEI-% were statistically different (P = 0.035 and 0.047, respectively) among the three groups. In BEB patients, the BEI-% was significantly increased in younger compared with older patients (P = 0.008). The most frequent adverse events were upper lid ptosis, diplopia, ecchymosis, and localized bruising. Conclusions This long-term multicentre study supports a high efficacy and good safety profile of BoNT-A for treatment of BEB, HFS, and EN. The BEI indexes indicate a significantly greater BoNT-A-dose escalation for BEB patients compared with HFS or EN patients and a significantly greater BEI-% in younger vs older BEB patients. These results confirm a greater efficacy in the elderly and provide a framework for long-term studies with a more flexible and reliable evaluation of drug-dose escalation. Eye (2010) 24, 600-607; doi:10.1038/eye.2009.192; published online 24 July 2009