A new clinical trial compared four botulinum toxin A formulations for treating glabellar lines, revealing measurable differences in onset and duration of effect.
In the study, researchers randomly assigned 143 female patients aged 30 to 65 years to receive one of four products: onabotulinum toxin A, abobotulinum toxin A, prabotulinum toxin A, or incobotulinum toxin A.
The participants received injections in the glabellar region and were monitored for over 6 months. The researchers used three-dimensional (3D) imaging to objectively measure facial muscle strain during expressions, such as frowning, prior to and following treatment.
Abobotulinum toxin A and prabotulinum toxin A showed the fastest onset, with noticeable strain reduction by day 3. Onabotulinum toxin A and incobotulinum toxin A had slower initial effects. By day 30, all four formulations reached peak effect, reducing glabellar strain by more than 85% compared with baseline.
At day 180, just prabotulinum toxin A and incobotulinum toxin A retained significant effects, whereas the effects of the other two products declined toward baseline. The participants with more severe baseline glabellar strain experienced greater improvements across all groups.
The researchers also collected patient-reported outcomes using the FACE-Q survey. The participants rated satisfaction with appearance in categories like forehead, eyes, and lines between the eyebrows. Scores improved in all groups and remained elevated for several months. The strongest correlation between objective improvement and satisfaction was in the area between the eyebrows.
The researchers assessed untreated areas of the face, specifically the outer corners of the eyes. As glabellar strain decreased, muscle strain in this lateral canthal region increased slightly during the first month, suggesting a possible compensatory response. This effect returned to baseline by the third month.
No adverse events occurred during the trial. All treatments were administered at standard on-label doses by a single masked physician. Preparation and imaging were handled independently to maintain objectivity.
Use of 3D photogrammetry allowed the researchers to quantify both short-term and long-term effects across formulations. While all products were effective, abobotulinum toxin A and prabotulinum toxin A demonstrated faster onset, and prabotulinum toxin A and incobotulinum toxin A showed sustained results at 6 months.
The findings provided clinicians with objective, comparative data on botulinum toxin A performance over time, helping guide individualized treatment choices based on patient goals.
Full disclosures can be found in the published study.
Source: JAMA Dermatology