Experience of up to ten years treatment with albumin-diluted botulinum toxin type A

Introduction: Only few data regarding the long-term follow-up of patients treated with albumin-diluted botulinum toxin (BTX) type A (Dysport®) have been published to date. In this study we present the data of 177 patients who received albumin-diluted BTX type A over a period of up to ten years with the diagnosis of dystonia, spasticity, writers cramp, blepharospasm, facial hemispasm and hyperhidrosis.

Methods: We performed a retrospective study of 177 patients who were treated in our BTX-outpatient clinic with albumin-diluted BTX type A (Dysport®) between 1996 and 2006.

The toxin was diluted in 20ml of 0.1% albumin solution to receive a concentration of 25 MU/ml. Different diagnosis with respective number of patients were included: cervical dystonia (74), spasticity (18), writers cramp (5), blepharospasm (44), facial hemispasm (32) and hyperhidrosis (4). Data of mean BTX dose, site and number of BTX injections per treated muscle, mean response rate, mean latency of response and mean total duration of response were derived from our database (Microsoft Office Access 2003). The response rate was based on a 0–3 scale (0=no effect; 3=marked improvement). SPSS v 14.0 (SPSS, Chicago, IL) was used for statistical analysis.

Results: Patients responded to the treatment on an average of 6.5 days after injection. The mean duration of beneficial effects was 11.5 weeks. Patients evaluated the clinical global improvement on a scale ranging from 0 to 3. The average value was 2.2 for the whole population, which demonstrates a pronounced effect. The most common side-effects were dysphagia in cervical dystonia and ptosis in blepharospasm and facial hemispasm. Specific side-effects for each indication are demonstrated.

Discussion: Our study support the conclusion that albumin-diluted BTX type A (Dysport®) is an effective and safe treatment with a low incidence of immunogenicity due to blocking antibodies even after 10 years of use.