A treatment protocol using an increased reconstitution and injection volume of abobotulinumtoxinA (aboBoNT-A, Dysport) is effective and did not show an increased risk of eyelid ptosis.
According to the current U.S. license for aboBoNT-A, a 300-unit vial of the powder formulation is reconstituted with either 1.5 mL or 2.5 mL 0.9% NaCl, and the injection protocol for glabellar lines (GL) is five 10-unit aliquots administered to the GL area using corresponding injection volumes of 0.05 mL or 0.08 mL per site.
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In their study, published in Drugs in Dermatology (September 2021), Joel Schlessinger MD, et al, posited that increasing the reconstitution volume to obtain a 0.1 mL volume of injection “minimizes the margin of error and is comparable to other botulinum toxin A preparations (onabotulinumtoxinA, [Botox] and incobotulinumtoxinA [Xeomin]).” This increased volume is approved for use with aboBoNT-A in some countries outside of the U.S., including in the European Union.
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To determine the safety and efficacy of the increased reconstitution and injection volume, the study’s authors performed a six-month, phase III, randomized, double-blind study, wherein subjects (18-64 years old) were administered either aboBoNT-A 50 U as five 0.1 mL injections (10 U) in the glabellar region following reconstitution of a 300-U vial in 3 mL (n=224) or placebo (n=77).
Assessments included time to onset of effect, investigator- and subject-assessed GL severity, subject satisfaction, aesthetic improvement and safety. The primary endpoint was composite 2-grade response at one month.
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The median time to onset was two days with 34% of subjects reporting effect on day one. At one month, the composite 2-grade responder rate was 65.8% for aboBoNT-A versus 0% for placebo; 91-92% of subjects in the treatment group had none-or-mild GL severity and 95–100% had a ≥1-grade GL severity improvement. At six months, 46-65% of aboBoNT-A-treated subjects had a sustained ≥1-grade improvement.
From month one to month six, ≥91% of subjects in the aboBoNT-A group were satisfied with the aesthetic outcome of their treatment. At six months, 99% of subjects treated with aboBoNT-A responded that they would recommend this treatment to family and 96% that they would like to receive the same treatment again.
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Treatment-related adverse events (TEAEs) occurred in 10.8% of subjects in the aboBoNT-A group and 7.8% in the placebo group, all were of mild or moderate intensity. The most common TEAEs during the study (occurring in >1 subject) were headache, eyelid ptosis and injection-site pain.
Three subjects (1.3%) developed eyelid ptosis after injection of aboBoNT-A. The authors noted that the safety results for this injection volume were consistent with and, in fact, lower than in the prescribing information for aboBoNT-A and other toxin products used in GL treatment, indicating no increase in local spread of toxin with the larger injection volume. In addition, there was a low rate of injection site pain (0.4% in the aboBoNT-A group).
