Background: A new formulation of botulinum neurotoxin type A (BoNTA-ABO; Dysport [abobotulinumtoxinA]; Medicis Aesthetics, Scottsdale, AZ) was recently approved by the US Food and Drug Administration for the treatment of moderate to severe glabellar lines.
Objective: To assess the long-term safety of repeat administrations of BoNTA-ABO for the treatment of glabellar lines, including variable dosing. This report summarizes an interim analysis that does not address the efficacy profile.
Methods: Over 24 months, 1415 subjects underwent open-label retreatment with BoNTA-ABO. Patients were retreated with 50 units or a variable dose of 50, 60, 70, or 80 units based on gender and muscle mass. Dose was divided among five points in the glabellar region. Retreatments were performed if at least 85 days had elapsed between treatments and the glabellar line severity score was reassessed as moderate or severe. Patients were followed up at seven, 14, and 30 days postinjection, then monthly. Endpoints were adverse events (AE).
Results: Of 1415 patients, 932 (66%) experienced at least one AE. The rate of treatment-emergent AE (TEAE) was similar in both the fixed- and variable-dose groups. Most TEAE were rated mild (70%) or moderate (20%). The majority (87%; 3361/3861) of all TEAE instances were considered not related or unlikely to be related to study treatment. The overall incidence of TEAE and related events remained relatively constant or decreased over repeat cycles.
Conclusions: Multiple cycles with fixed or variable dosing of BoNTA-ABO are well tolerated. There was no evidence of cumulative safety issues because the incidence of AE remained relatively constant or decreased over repeated treatment cycles.