A Study to Assess the Effectiveness of BOTOX (Botulinum Toxin Type A) Injections for the Change of Masseter Muscle Prominence in Adult Participants (MMP EU P3)

BOTOX® (Botulinum Toxin Type A) for the Reduction of Masseter Muscle Prominence: A Phase 3, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study

The masseter muscle is one of the muscles in the lower face used for chewing. Prominence of the masseter muscle can appear as a widened and square lower face shape, which is an aesthetic concern for individuals who prefer a narrower and more ovoid lower face shape. Treatments are available for masseter muscle prominice (MMP), but researchers are looking for new non-surgical treatments. This study will assess adverse events and effectiveness of BOTOX in adult participants with MMP.

BOTOX is being investigated for the treatment of MMP. Participants are placed in 1 of 2 groups, called treatment arms. Each group receives a different treatment. There is 1 in 4 chance that participants will be assigned to placebo. Around 248 adult participants with MMP will be enrolled in the study at approximately 30 sites in Europe.

Participants will receive either BOTOX or Placebo administered as 6 intramuscular injections to the masseter on Day 1. Participants who are eligible for retreatment will be given BOTOX on Day 180 and will be followed for up to 6 months.

There may be higher treatment burden for participants in this trial compared to their standard of care. Participants will attend regular visits during the study at a hospital or clinic. The effect of the treatment will be checked by medical assessments, checking for side effects and completing questionnaires.

Study Overview

• Status: Completed
• Conditions: Masseter Muscle Prominence
• Intervention / Treatment: Drug: BOTOX; Drug: Placebo

• Study Type: Interventional
• Enrollment (Actual): 249
• Phase: Phase 3

Contacts and Locations

Study Locations

• Belgium
  • Antwerpen
    • Beerse, Antwerpen, Belgium, 2340
      • Da Vinci Clinic /ID# 246731
    • Schilde, Antwerpen, Belgium, 2970
      • Evolve Clinic /ID# 246729
  • Brussels Capital
    • Jette, Brussels Capital, Belgium, 1090
      • Universitair Ziekenhuis Brussel /ID# 246311
  • Oost-Vlaanderen
    • Melle, Oost-Vlaanderen, Belgium, 9090
      • Lightfalls Clinic /ID# 247335
• Bulgaria
  • Plovdiv, Bulgaria, 4000
    • Dermavist - Group Practice for Specialized Medical Care for Skin Disease /ID# 247630
  • Sofia, Bulgaria, 1700
    • Medical Centre Dermatology Dr. Denkova EOOD /ID# 246591
  • Sofia, Bulgaria, 1407
    • Medical Center Derma Vita EOOD /ID# 247327
• France
  • Antibes, France, 06160
    • Mediti /Id# 246875
  • Cannes, France, 06400
    • Cabinet Dermatologie et Esthetique /ID# 246871
  • Paris, France, 75007
    • Cabinet médical /ID# 246873
  • Toulouse, France, 31000
    • Cabinet de Chirurgie Plastique et Esthétique /ID# 246872
• Germany
  • Hamburg, Germany, 20146
    • Universitaet Hamburg /ID# 247503
  • Bavaria
    • Munich, Bavaria, Germany, 80333
      • Hautok and Hautok-cosmetics /ID# 246600
    • Munich, Bavaria, Germany, 80333
      • Studienzentrum Theatiner46 /ID# 246601
  • North Rhine-Westphalia
    • Cologne, North Rhine-Westphalia, Germany, 50996
      • Hautzentrum Koeln /ID# 247502
    • Düsseldorf, North Rhine-Westphalia, Germany, 40212
      • Privatpraxis Dr. Hilton & Partner /ID# 246602
• Italy
  • Latina, Italy, 04100
    • Azienda Unita Sanitaria Locale Latina /ID# 246835
  • Roma, Italy, 00128
    • Fondazione Policlinico Universitario Campus Bio-Medico /ID# 246836
  • Verona, Italy, 37134
    • CRC - Centro Ricerche Cliniche di Verona S.r.l. /ID# 246834
• Spain
  • Madrid, Spain, 28006
    • Grupo Pedro Jaen /ID# 246485
  • Madrid, Spain, 28008
    • Clinica Robega /ID# 252239
  • Pontevedra
    • Vigo, Pontevedra, Spain, 36201
      • Gavín Dermatólogos /ID# 252120
  • Valencia
    • Valencia, Valencia, Spain, 46004
      • Clinica Alejandria /ID# 247380
• United Kingdom
  • Edinburgh, United Kingdom, EH3 6RS
    • Dr Nestor's Medical Cosmetic Centre /ID# 246437
  • London, United Kingdom, W1H 6AZ
    • Interface Aesthetics Training Limited /ID# 248115
  • Sutton Coldfield, United Kingdom, B74 2UG
    • MediZen /ID# 246431
  • North Lanarkshire
    • Coatbridge, North Lanarkshire, United Kingdom, ML5 3AP
      • Waverley Medical Practice /ID# 246432

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Body mass index < 30 kg/m^2 using the calculation: BMI = weight (kg)/height (m)^2, rounded to the nearest whole number.

• Participants meets the following criteria:

  • Bilateral Grade 4 or Grade 5 MMP (identical grades for left and right side of the face), as determined at screening and at the Day 1 visit by the investigator using the MMPS.
  • Bilateral Grade 4 or Grade 5 MMP (identical grades for left and right sides of the face), as determined at the Day 1 visit by the participant using the MMPS-P.
  • MMP grades, as assessed by investigator and participant, do not need to be identical but have to be a minimum of Grade 4 with bilateral symmetry at Day 1.
• Participants who responded "A lot" or "Extremely" bothered by the appearance of their MMP as measured by the Bother Impact Assessment for Masseter Muscle Prominence (BIA-MMP) and attain a total score of ≥ 15 on the Lower Facial Shape Questionnaire - Impact Assessment (LFSQ-IA), determined at the Day 1 visit.

Exclusion Criteria:

• Has current intraoral infection, including infection of the mouth or gums, or facial skin infection requiring medical treatment in the opinion of the investigator.
• Has weakness of the masseter, pterygoid, or temporalis muscles due to trauma, facial nerve injury, or other condition that could interfere with normal chewing and jaw clenching, as determined by the investigator.
• Excess lower facial fat, jowling, loose or lax skin in lower face, or parotid gland prominence that could interfere with MMPS or MMPS-P grading, as determined by the investigator.
• Has 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.
• History of dental or surgical procedure for lower facial shaping or masseter muscle reduction.
• History of any soft tissue fillers in the jawline.
• Has prior exposure to botulinum toxin of any serotype to any part of the body (not including masseter muscle) within the 3 months prior to Day 1.
• History of or current TMJD, or presence of signs/symptoms of possible TMJD in the opinion of the investigator.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: Triple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Double-Blind Period: Botox; Participants will receive 6 intramuscular injections of BOTOX to the masseter on Day 1.	Drug: BOTOX; Intramuscular Injections; Other Names: Botulinum Toxin Type A
Placebo Comparator: Double Blind Period: Placebo; Participants will receive 6 intramuscular injections of Placebo to the masseter on Day 1.	Drug: Placebo; Intramuscular Injections
Experimental: Open-Label Period: Botox; Participants who are eligible for retreatment will be given open-label BOTOX on Day 180 and will be followed for up to 6 months	Drug: BOTOX; Intramuscular Injections; Other Names: Botulinum Toxin Type A

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Achievement of 2-grade or more improvement from baseline on the Masseter Muscle Prominence Scale (MMPS) as assessed by the Investigator	The investigator assessed the severity of the participant's MMP using the MMPS 5-point scale where: 1=minimal (best), 2=mild, 3=moderate, 4=marked, and 5=very marked (worst).	Day 90
Achievement of 2-grade or more improvement from baseline on the Masseter Muscle Prominence Scale - Participant (MMPS-P) as assessed by the Participant	The participant assessed the severity of their MMP using the MMPS-P 5-point scale where: 1=not at all pronounced (best), 2=mildly pronounced, 3=moderately pronounced, 4=pronounced, and 5=very pronounced (worst).	Day 90

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Response of "Very Satisfied" or "Satisfied" on the Lower Facial Shape Questionnaire - Treatment Satisfaction Assessment (LFSQ-TXSAT)	The LFSQ-TXSAT measures the participant's satisfaction with the effect of treatment on the appearance of their lower face where 2=Very satisfied, 1=Satisfied, 0=Neither satisfied nor dissatisfied, -1=Dissatisfied, -2=Very dissatisfied.	Day 90 to Day 180
Response of "Not at all bothered" or "A little bothered" on the Bother Impact Assessment for Masseter Muscle Prominence (BIA-MMP)	The BIA-MMP is a single item evaluation of how bothered the participant is by the appearance of their lower face where 0=Not at all bothered, 1=A little bothered, 2=Somewhat bothered, 3=A lot bothered, 4=Extremely bothered.	Day 90 to Day 180
Change from baseline in lower facial volume (cm^3)	Lower facial volume is calculated from standardized images	Day 90
Change from baseline in lower facial width (mm)	Lower facial width is calculated from standardized images	Day 90
Change from baseline in Lower Facial Shape Questionnaire - Impact Assessment (LFSQ-IA) summary score	The LFSQ-IA is a 6-item assessment that measures psychosocial impact of the appearance of the lower face where 0= Not at all, 1=A little bit, 2=Somewhat, 3=Quite a bit and 4=Extremely.	Day 90 to Day 180

Collaborators and Investigators

• Sponsor: AbbVie
• Investigators: Study Director: ABBVIE INC., AbbVie

Publications and helpful links

Helpful Links

• Related Info

Study record dates

Study Major Dates

• Study Start (Actual): October 17, 2023
• Primary Completion (Actual): November 20, 2025
• Study Completion (Actual): November 20, 2025

Study Registration Dates

• First Submitted: September 29, 2023
• First Submitted That Met QC Criteria: September 29, 2023
• First Posted (Actual): October 5, 2023

Study Record Updates

• Last Update Posted (Actual): December 10, 2025
• Last Update Submitted That Met QC Criteria: December 4, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: Botulinum Toxin Type A; BOTOX; Masseter Muscle Prominence
• Additional Relevant MeSH Terms: Amino Acids, Peptides, and Proteins; Proteins; Biological Factors; Hydrolases; Enzymes; Enzymes and Coenzymes; Botulinum Toxins; Metalloendopeptidases; Endopeptidases; Peptide Hydrolases; Metalloproteases; Bacterial Proteins; Bacterial Toxins; Toxins, Biological; Botulinum Toxins, Type A
• Other Study ID Numbers: M23-123; 2022-500568-37-00 (Other Identifier: EU CT)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: AbbVie is committed to responsible clinical trial data sharing. This includes access to anonymized, individual and trial-level data (analysis data sets), as well as other information.
• IPD Sharing Time Frame: For details on when studies are available for sharing visit https://vivli.org/ourmember/abbvie/
• IPD Sharing Access Criteria: To learn more about the process, or to submit a request, visit the following link https://www.abbvieclinicaltrials.com/hcp/data-sharing/
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No