Spread of PrabotulinumtoxinA-xvfs Versus OnabotulinumtoxinA in the Treatment of Forehead Rhytides

Ten subjects will be enrolled in the study. Each subject will have their left and right forehead randomly assigned to receive 4 units of PrabotulinumtoxinA-xvfs or OnabotulinumtoxinA. Subjects will be reassessed at 2 weeks for evaluation of rhytide diminution around each injection point to assess relative diffusion of each drug in the forehead.

This is a prospective, single-center, blinded, randomized, split-face study to investigate the area of spread or diffusion of onabotulinumtoxinA and prabotulinumtoxinA at the same dilution and dose in the treatment of forehead lines in adult subjects. Ten adult subjects, 18 years or older, with moderate-to-severe dynamic and none-to-minimal static forehead lines will be enrolled. Upon enrollment and after a thorough review of the inclusion and exclusion criteria as well as obtaining written and informed consent, each subject will be randomized to have either their right forehead or left forehead treated with 4 units or 0.1 cc of prabotulinumtoxinA 2.5 cm above the orbital rim. As a control, the contralateral forehead half will receive 4 units or 0.1 cc of onabotulinumtoxinA at the same dilution. If applicable, a urine pregnancy test will be obtained prior to treatment. Subjects may be treated on the same day that they are screened and provide informed consent. Given the small volume of injection, tuberculin hubless syringes will be used to ensure accuracy of specific injection volumes. Injections will be delivered intramuscularly with the needle at a 90-degree angle or perpendicular to the skin surface. The left and right-side assignment will be determined based on the treating physician's selection of a sealed envelope using random numbers on the treatment day. Following initial treatment, the subjects will be re-evaluated at a Day 14. Surface area of rhytide reduction will be measured in centimeters squared (incorporating length and width measurements) two-weeks post-injection to assess differences, if any, in rhytid reduction on each side of the forehead by a blinded investigator. The field of rhytid reduction (visual absence of horizontal forehead rhytids) will be measured while the frontalis fully contracted. Any adverse events will be recorded at the 2-week follow up. After the Day 14 assessment subjects will exit the study after which the investigator will assess the patient for any asymmetry and if the investigator deems it appropriate and the subject desires it, a touch up correction will be performed. Subjects will be photographed at baseline and two weeks after treatment using Visia and 2D photography. Photos will be taken before and after marking the points of injection. Moreover, photos will be taken both with the frontalis muscle fully relaxed and fully contracted.