Long-term safety of abobotulinumtoxinA for the treatment of glabellar lines: results from a 36-month, multicenter, open-label extension study.

Background Because abobotulinumtoxinA treatment for glabellar lines must be repeated regularly to prevent recurrence, understanding the safety and effectiveness of long-term, repeated administration of abobotulinumtoxinA is important. Objective To report the long-term safety and efficacy of abobotulinumtoxinA in patients with moderate to severe glabellar lines. Methods and Materials AbobotulinumtoxinA was administered to 1,415 patients in multiple cycles over 24 months as a fixed dose of 50 U or as a dose based on muscle mass and sex (women: 50–70 U; men: 60–80 U). Adverse events were assessed after each visit on days 7, 14, and 30 and monthly thereafter; monitoring continued every 3 months for a total safety monitoring duration of 36 months or less. Results Nine hundred ninety-one (70%) patients reported treatment-emergent adverse effects (TEAEs); most events were mild (70%) or moderate (20%) in severity. The rate of TEAEs did not increase over 24 months of repeated treatment (mean 5.6 cycles; range 1–9). Treatment-related eyelid ptosis followed 53 of 7,938 (0.7%) treatments, all of which resolved spontaneously. Conclusions Multiple cycles of abobotulinumtoxinA treatment over 24 months were well tolerated and effective for the correction of glabellar lines, with no evidence of cumulative safety problems.