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Dysport: The New Kid on the Block

A placebo-controlled trial demonstrated the safety and efficacy of this newly approved botulinum toxin type A product for smoothing the brow.

Dysport was approved by the FDA in April 2009 for the treatment of glabellar wrinkles. Are its safety and efficacy comparable to Botox? In this manufacturer-funded, phase III trial, 816 patients with moderate-to-severe glabellar rhytids who received variably dosed Dysport or placebo were followed for 5 months. Investigators rated the size of patients' corrugator and procerus muscles as small, medium, or large and set the dosage accordingly: 50, 60, or 70 units, respectively, in women and 60, 70, or 80 units in men.

Median time to the onset of effect was 4 days. The median duration of the effect was assessed at 109 days by blinded evaluators and at 107 days by patients. At 5 months, 85% of patients continued to show some response. The effect endured longer in black patients than in the group as a whole. The response rate was 94% in patients with moderate rhytids and 80% in those with severe rhytids. Subgroup analysis at 30 days showed lower response rates in men and patients older than 65 (65% for both). The higher the dose (i.e., the thicker the muscles), the lower was the response rate at 30 days (range: 50-unit recipients, 96%; 80-unit recipients, 61%). Ptosis was the only adverse effect to occur more often in the Dysport group (2% of recipients) than in the placebo group; its occurrence was unrelated to dosage size. Electrocardiography conducted in a subgroup of patients showed no evidence of Dysport-related prolonged QT intervals.

Comment: At the doses used in this study, appropriately titrated for muscle size, the effectiveness and duration of action of Dysport seem to be very similar to those of Botox. Men and patients with thick muscles are less responsive to Dysport injections, requiring significantly higher doses for a satisfactory effect. In this trial, Dysport doses were approximately 2.5 times the size of Botox doses normally used in the glabella. The rate of ptosis reported here is about double that reported in other studies of Dysport and Botox. As clinicians gain experience with this agent, the ptosis rate should drop considerably. These results suggest that Dysport will present a viable alternative to Botox.

— George J. Hruza, MD

Published in Journal Watch Dermatology November 13, 2009

Citation(s):

Kane MAC et al. Evaluation of variable-dose treatment with a new U.S. botulinum toxin type A (Dysport) for correction of moderate to severe glabellar lines: Results from a phase III, randomized, double-blind, placebo-controlled study. Plast Reconstr Surg 2009 Nov; 124:1619. (http://dx.doi.org/10.1097/PRS.0b013e3181b5641b)

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