Botulinum Toxin Type A (BOTOX®) Treatment of Masseter Muscle Hypertrophy

Study Overview
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Brief Summary
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This study will evaluate the safety and efficacy of a range of doses of botulinum toxin Type A (BOTOX®) for the treatment of patients with bilateral Masseter Muscle Hypertrophy (MMH).

Official Title
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BOTOX® Treatment of Masseter Muscle Hypertrophy

Conditions
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Masseter Muscle Hypertrophy

Intervention / Treatment
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* Biological: botulinum toxin Type A
* Drug: Normal saline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: -Participants with Masseter Muscle Hypertrophy Exclusion Criteria: Diagnosis of Myasthenia gravis, Eaton-Lambert syndrome, amyotrophic lateral sclerosis, or any other condition that might interfere with neuromuscular function Prior botulinum toxin treatment of any serotype to the masseter muscle or lower face History of dental or surgical procedure for lower facial shaping or masseter muscle reduction History of or current temporomandibular joint disorder (TMJD)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: BOTOX® 24U<br>Botulinum Toxin Type A (BOTOX®) 24U total dose administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable. | Biological: botulinum toxin Type A<br>* Botulinum toxin Type A (BOTOX®) administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable.<br>* Other names: onabotulinumtoxinA;|
| Active Comparator: BOTOX® 48U<br>Botulinum Toxin Type A (BOTOX®) 48U total dose administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable. | Biological: botulinum toxin Type A<br>* Botulinum toxin Type A (BOTOX®) administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable.<br>* Other names: onabotulinumtoxinA;|
| Active Comparator: BOTOX® 72U<br>Botulinum Toxin Type A (BOTOX®) 72U total dose administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable. | Biological: botulinum toxin Type A<br>* Botulinum toxin Type A (BOTOX®) administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable.<br>* Other names: onabotulinumtoxinA;|
| Active Comparator: BOTOX® 96U<br>Botulinum Toxin Type A (BOTOX®) 96U total dose administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable. | Biological: botulinum toxin Type A<br>* Botulinum toxin Type A (BOTOX®) administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable.<br>* Other names: onabotulinumtoxinA;|
| Placebo Comparator: Placebo<br>Placebo (Normal saline) administered intramuscularly to the bilateral masseter muscles on Day 1 and retreatment at Day 180 if applicable. | Drug: Normal saline<br>* Normal saline (placebo) administered intramuscularly to the bilateral masseter muscles.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline in Lower Facial Volume Using VECTRA 3D Images | Lower facial volume was calculated from 3-dimensional (3D) images captured with the VECTRA M3 3D Stereophotogrammetry imaging system and was analyzed using computer assisted systems and predetermined facial landmarks. The difference in volume was measured between the select region of the baseline surface 3D model and the select region of the posttreatment surface 3D model. A negative change from Baseline (decrease in volume) indicates improvement. | Baseline (Day 1) to Day 90 of Treatment Cycle 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants Who Achieved a Masseter Muscle Prominence Scale (MMPS) Grade ≤ 3 as Assessed by the Investigator | The investigator used visual inspection and palpation to grade the prominence of the participant's masseter muscle on the left and right sides of the face using the MMPS where: 1=minimal prominence (best), 2=mild prominence, 3=moderate prominence, 4=marked prominence, 5=very marked prominence (worst). The percentage of participants with grade 3 or less is reported. | Day 90 of Treatment Cycle 1 |