Comparison of two formulations of botulinum toxin type A for the treatment of glabellar fines: A double-blind, randomized study

Background: Different formulations of botulinum toxin type A can behave differently. There has been little clinical research directly comparing formulations. Objective: We sought to compare the efficacy and tolerability of two botulinum toxin type A formulations-BoNTA(1) and BoNTA(2)-in the treatment of moderate and severe glabellar lines. Methods: Sixty-two patients with moderate or severe glabellar lines at maximum contraction were randomly assigned to receive 20 U of BoNTA(1) or 50 U of BoNTA(2) (20% in the procerus muscle, 80% in the corrugator muscles). Results: The incidence of 1-grade improvement or greater in glabellar line severity at maximum contraction was as follows: 77% (BoNTA(1)) versus 59% (BoNTA(2)) at week 12, 53% versus 28% at week 16. The estimated incidence of relapse was 23% (BoNTA(1)) versus 40% (BoNTA(2)) at week 16. Both formulations were similarly, well tolerated. Limitations: Few male and non-Caucasian subjects were studied. Conclusion: BoNTA1 offered more prolonged efficacy than BoNTA(2) in the treatment of glabellar lines at the dose ratio of 2.5:1 (BoNTA(2) :BoNTA(1)) used in this study.