Pilot study of the safety and efficacy of Myobloc (botulinum toxin type B) for treatment of axillary hyperhidrosis.

BACKGROUND: Botulinum toxin type B (BTX-B, Myobloc, San Francisco, CA, USA) was FDA-approved for the treatment of cervical dystonia in December 2000. It has since been used off-label for the treatment of axillary hyperhidrosis. However, there are sparse data in the medical literature evaluating the safety and efficacy of Myobloc (botulinum toxin type B) for this indication.

OBJECTIVE: To assess the safety, efficacy and duration of action of Myobloc (botulinum toxin type B) in the treatment of bilateral axillary hyperhidrosis.

METHODS: This study was a double-blinded, randomized, pilot study conducted in an outpatient office setting at a private academic medical center beginning in November 2001. Twenty-three male and female volunteers between the ages of 18 and 80 were screened for participation; 20 participants with primary axillary hyperhidrosis were enrolled. Participants were injected subcutaneously with either Myobloc (botulinum toxin type B) (2500 U, or 0.5 ml, per axilla) or 0.5 ml vehicle (100 mM NaCl, 10 mM succinate, and 0.5 mg/ml human albumin) into bilateral axillae. Participants who received placebo were rolled over and received Myobloc (botulinum toxin type B) at subsequent visits. All participants were followed until sweating returned to baseline levels. This trial was initially conceived as a placebo-controlled study; however, owing to the insufficient size of the placebo group, the placebo arm of this trial was dropped during data analysis. The main outcome measures were safety, efficacy, and duration of effect.

RESULTS: According to participant assessment of axillary hyperhidrosis improvement (A-HI) and quality of life (A-HQOL) scores and the physician assessment scores, a significant difference was observed in treatment response at Day 30 in the participants receiving Myobloc (botulinum toxin type B) injections. Duration of action ranged from 2.2 to 8.1 months (mean 5.0 months). The adverse event profile included bruising, flu-like symptoms, and dry eyes.

CONCLUSION: Myobloc (botulinum toxin type B) proved to be safe and efficacious for the treatment of bilateral axillary hyperhidrosis. More studies are needed to assess the duration of response using different doses of Myobloc (botulinum toxin type B).