Improvement of platysma prominence with onabotulinumtoxinA: Safety and efficacy results from a randomized, double-blinded, placebo-controlled phase 3 trial

Background: Platysma prominence (PP) refers to the undesirable effects that may occur with platysma muscle contraction. Objective: Evaluate safety and efficacy of onabotulinumtoxinA for improving Moderate (Grade 3) to Severe (Grade 4) PP in adults. Methods: Participants were randomized 1:1 to receive a total dose of onabotulinumtoxinA 26, 31, or 36 U or placebo on Day 1 and monitored for 120 days. Dosage was administered via superficial intramuscular injections into the platysma muscle based on baseline PP severity. Results: At Day 14, 32.3% of onabotulinumtoxinA-treated participants in the intent-to-treat population versus 1.9% who received placebo achieved investigator- and participant-rated Grade 1 or 2 (Minimal or Mild) and >= 2-grade improvement from baseline in PP severity, while 56.9% and 51.7% achieved Grade 1 or 2 on investigator's and participant's assessments, respectively (all P < .0001). OnabotulinumtoxinA-treated participants reported higher satisfaction, less bother from jawline and vertical neck band appearance, and reduced psychosocial impact versus placebo (all P < .0001). Adverse event incidence was similar between onabotulinumtoxinA and placebo. No events of dysphagia or muscular weakness were reported. Limitations: A single onabotulinumtoxinA treatment was evaluated. Conclusion: OnabotulinumtoxinA showed favorable tolerability and significantly improved PP severity and patient-reported outcomes in participants with moderate-to-severe PP.