A Study To Assess the Safety and Effects of OnabotulinumtoxinA (BOTOX) Intramuscular Injection in Adult Participants With Platysma Prominence

A Phase 3 Multicenter, Randomized, Double-blind, Placebo-controlled Study to Evaluate the Safety and Efficacy of BOTOX® (Botulinum Toxin Type A) Purified Neurotoxin Complex for the Treatment of Platysma Prominence

The purpose of the study is to evaluate the safety and effects of onabotulinumtoxinA (BOTOX) for the temporary improvement in the appearance of platysma prominence.

Study doctors will randomize participants into 1 of the 2 groups, called treatment arms. There is a 1 in 2 chance that a participant will be assigned to placebo. Around 400 participants will be enrolled in the study across approximately 35 sites in USA, Belgium, Canada, Germany and the UK.

Participants will receive a single treatment of intramuscular injection of onabotulinumtoxinA (BOTOX) or placebo on Day 1 during this 4 month long study.

Participants will attend regular monthly visits during the study at the study site.

Inclusion Criteria:

• Participants must voluntarily sign and date an informed consent, approved by an independent ethics committee (IEC)/institutional review board (IRB), prior to the initiation of any screening or study specific procedures
• Are willing and able to comply with procedures required in the protocol
• Adult male or female, at least 18 years old at the time of signing the informed consent
• Good health as determined by medical history, physical examination, vital signs, and investigator's judgment

Exclusion Criteria:

• Any medical condition that may put the participant at increased medical risk with exposure to BOTOX, including diagnosed myasthenia gravis, Eaton-Lambert syndrome, amyotrophic lateral sclerosis, or any other condition that might interfere with neuromuscular function
• Participant has an anticipated need for treatment with botulinum toxin of any serotype for any indication during the study (other than study intervention)
• Anticipated need for surgery or overnight hospitalization during the study
• Females who are pregnant or breastfeeding and are considering becoming pregnant or donating eggs during the study
• Known immunization or hypersensitivity to any botulinum toxin serotype
• History of clinically significant (per investigator's judgment) drug or alcohol abuse within the last 6 months
• Lower facial and neck hair, scarring (e.g., acne), or other abnormal variations that may interfere with photography (such that photograph is not acceptable)
• Tattoos, jewelry, or clothing that cannot be removed, and that obscure the target area of interest