Comparison of Botulinum Toxin A Formulations for Glabellar Strain Treatment in Women

Importance Multiple botulinum toxin A formulations were approved by the US Food and Drug Administration for treating the glabellar rhytids. A comparative quantitative evaluation of their effects on the glabella has not been conducted. Objective To provide an objective quantitative assessment of the effect of 4 botulinum toxin A formulations on glabellar strain across using dynamic 3-dimensional photogrammetry. Design, Setting, and Participants This single-center, double-blind clinical trial, conducted at the University of Pennsylvania Division of Plastic Surgery clinic, randomized 143 female individuals aged 30 to 65 years into 4 arms receiving different botulinum toxin A formulations on day 0 and with follow-up at days 3, 30, 90, and 180. Dynamic 3-dimensional photogrammetry and surveys were collected from March 2022 to June 2023 and analyzed from July 2023 to April 2024. Interventions Participants were randomized 1:1:1:1 into 4 treatment arms: 1 dose of 20 units of onabotulinum toxin A (OBoNT/A); 1 dose of 60 units of abobotulinum toxin A (ABoNT/A); 1 dose of 20 units of prabotulinum toxin A (PBoNT/A); or 1 dose of 20 units of incobotulinum toxin A (IBoNT/A) into the glabellar region (GR). Main Outcomes and Measures The primary outcome was change in GR dynamic strain after injection over time. Secondary outcomes included changes in patient-reported satisfaction, the relationship between baseline strain severity and postinjection improvement in strain, and the effect on the strain of the untreated lateral canthal region. Results This study recruited 143 female individuals with a mean (SD) age of 43.5 (9.8) years. ABoNT/A and PBoNT/A had the fastest onset at day 3. PBoNT/A and IBoNT/A retained efficacy at day 180 compared with their baseline. Increasing baseline glabellar strain severity resulted in increased improvement with treatment. Lateral canthal region strain increased with decreasing GR strain. PBoNT/A was significantly more effective at day 180 than OBoNT/A. All arms experienced improvement in related FACE-Q module scores up to 90 days. Conclusions and Relevance This randomized clinical trial found that ABoNT/A and PBoNT/A displayed the most rapid onset of effect. The peak effect is similar across all toxins. When measuring strain at approximately 6 months, some toxins remain significant relative to their own baseline or compared with other specific toxins. Trial Registration ClinicalTrials.gov Identifier: NCT05167864