Botulinum Toxin Type A Injection Sites for Oral Commissure Ptosis

NCT07646886 | Not Yet Recruiting Phase 4 DMC

• 1 other identifier: PekingUDAO
• Study Type: interventional
• Target: 266
• Locations: 0 countries
• Sites: N/A

Brief Summary

This multicenter, prospective, randomized parallel-controlled, assessor-blinded clinical trial aims to address the core clinical pain point of lack of high-level evidence and non-standardized operation in injection site selection for BTX-A treatment of oral commissure ptosis. A total of 266 eligible subjects will be randomly assigned in a 1:1 ratio to receive either upper DAO or lower DAO BTX-A injection. The study will compare the clinical efficacy, time-effect characteristics and safety profiles of the two regimens, and conduct stratified analysis of treatment response in different patient subtypes. The results will determine the optimal injection site for Chinese population, establish standardized operation specifications, fill the international evidence gap, and provide level I evidence for clinical practice.

Conditions

Facial Aging; Melomental Folds; Oral Commissure Ptosis

Keywords

Botulinum Toxin Type A; Oral Commissure Ptosis; Melomental Folds; Depressor Anguli Oris Muscle; Randomized Controlled Trial; Injection Site

Outcome Measures

Primary Outcomes (1)

• Improvement of Bilateral Oral Commissure Ptosis Angle from Baseline at 1 Month Post-Treatment

  The primary endpoint is the change in bilateral oral commissure ptosis angle (∠oba) from baseline. The angle is measured on standardized frontal facial photographs at rest by 3 independent assessors who are completely blinded to group assignment. The average value of 3 measurements is used as the final result.

  30±3 days after treatment

Secondary Outcomes (9)

• Improvement of Oral Commissure Ptosis Angle at Maximum Smile and Maximum Depression Position

  1, 3, 6 months after treatment

• Vertical Elevation Amplitude of the Oral Commissure

  1, 3, 6 months after treatment

• Merz Facial Aesthetic Scale Score

  1, 3, 6 months after treatment

• Global Aesthetic Improvement Scale (GAIS)

  1, 3, 6 months after treatment

• Patient Satisfaction Score (FACE-Q)

  1, 3, 6 months after treatment

Study Arms (2)

Upper Depressor Anguli Oris Injection

EXPERIMENTAL

Single subcutaneous injection of OnabotulinumtoxinA (Botox®, Allergan, USA) into the upper half of the depressor anguli oris (DAO) muscle. * Drug preparation: 100U/vial reconstituted with 2mL sterile normal saline to a final concentration of 50U/mL * Injection sites: 3 points per side: ① Inferolateral to the oral commissure (skin depression site during DAO contraction); ② Midpoint of the line from the oral commissure to the mandibular line along the DAO course; ③ Midpoint of the line connecting the first two points * Dosage: 1U (0.02mL) per point, total 6U bilaterally * Technique: 45° semi-recumbent position, 1mL syringe with 34G 1.5mm needle, vertical subcutaneous injection with needle bevel facing outward; gentle pressure with sterile cotton swab for 15-30 seconds post-injection; no massage allowed * Follow-up: 6 months after single injection

Drug: OnabotulinumtoxinA (Upper Depressor Anguli Oris Injection)

Lower Depressor Anguli Oris Injection

ACTIVE COMPARATOR

Single subcutaneous injection of OnabotulinumtoxinA (Botox®, Allergan, USA) into the lower half of the depressor anguli oris (DAO) muscle. * Drug preparation: Identical to the experimental group (100U/vial reconstituted to 50U/mL) * Injection sites: 3 points per side forming a triangle: ① Midpoint between the oral commissure axis and the motor endplate; ② 0.5cm medial to the midpoint of the vertical line from the motor endplate to the mandibular margin; ③ 0.5cm lateral to the same midpoint * Dosage: 1U (0.02mL) per point, total 6U bilaterally * Technique: Identical to the experimental group (needle parameters, injection depth, post-injection instructions) * Follow-up: 6 months after single injection

Drug: OnabotulinumtoxinA (Lower Depressor Anguli Oris Injection)

Interventions

OnabotulinumtoxinA (Upper Depressor Anguli Oris Injection) DRUG

Single subcutaneous injection of onabotulinumtoxinA into the upper half of the depressor anguli oris muscle, total dose 6U bilaterally.

Also known as: Botox®

Upper Depressor Anguli Oris Injection

OnabotulinumtoxinA (Lower Depressor Anguli Oris Injection) DRUG

Single subcutaneous injection of onabotulinumtoxinA into the lower half of the depressor anguli oris muscle, total dose 6U bilaterally.

Also known as: Botox®

Lower Depressor Anguli Oris Injection

Eligibility Criteria

• Age: 18 Years - 60 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Aged 18 to 60 years, any gender
• Meet the diagnostic criteria for oral commissure ptosis: bilateral oral commissure ptosis angle (angle between the oral commissure point and the horizontal line of the ipsilateral vermilion border) \> 1° at rest
• Have clear aesthetic demand for oral commissure ptosis improvement and can complete full-cycle follow-up
• No redness, swelling, ulcer, scar, deformity or active infection in the perioral and mental regions
• Have not participated in other interventional clinical trials within 3 months before enrollment

You may not qualify if:

• Hypersensitivity to botulinum toxin type A, lidocaine or excipients of injection preparations; or contraindications to botulinum toxin injection (myasthenia gravis, Lambert-Eaton syndrome, motor neuron disease, severe liver and kidney dysfunction, coagulation disorders, uncontrolled autoimmune diseases, malignant tumors)
• History of mid-lower facial botulinum toxin type A injection, soft tissue filling, laser/radiofrequency rejuvenation, perioral surgery or orthognathic treatment within 6 months before enrollment
• Planned perioral treatment within 6 months after enrollment that may affect efficacy evaluation
• Pregnant or lactating women, or those planning to become pregnant within 6 months
• Acquired oral commissure ptosis caused by facial nerve palsy/sequelae, perioral scar traction, severe jaw deformity or severe alveolar bone resorption
• Severe facial asymmetry (difference in bilateral oral commissure ptosis angle \> 2°)
• History of botulinum toxin allergy or severe adverse reactions after previous botulinum toxin injection
• Currently using aminoglycoside antibiotics, quinine, calcium channel blockers, anticoagulants or other drugs that may affect botulinum toxin efficacy or increase bleeding risk and cannot discontinue
• History of mental illness, drug/alcohol abuse, or poor compliance unable to complete follow-up
• Other conditions deemed unsuitable for enrollment by the investigator

Sponsors & Collaborators

• Peking University: lead

MeSH Terms

Interventions

Botulinum Toxins, Type A

Intervention Hierarchy (Ancestors)

Botulinum Toxins; Metalloendopeptidases; Endopeptidases; Peptide Hydrolases; Hydrolases; Enzymes; Enzymes and Coenzymes; Metalloproteases; Bacterial Proteins; Proteins; Amino Acids, Peptides, and Proteins; Bacterial Toxins; Toxins, Biological; Biological Factors

Study Officials

• Xi Gong, D.D.S

  Peking University School and Hospital of Stomatology

  PRINCIPAL INVESTIGATOR

• Minjie Chen, D.D.S

  Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine

  PRINCIPAL INVESTIGATOR

• Jian Li, D.D.S

  Wuhan University School of Stomatology

  PRINCIPAL INVESTIGATOR

• Yunpeng Li, D.D.S

  School of Stomatology, Air Force Medical University

  PRINCIPAL INVESTIGATOR

• Sien Zhang, D.D.S

  Guanghua School of Stomatology, Sun Yat-sen University

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Xi Gong, D.D.S

CONTACT

+86 15201304426; 15201304426@163.com

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Single-blinded design for outcomes assessors only. All facial photographs and measurement data are anonymized with all group and time point information removed. Injecting physicians do not participate in any efficacy assessment. All outcomes are evaluated by 3 independent third-party assessors who are completely blinded to the group assignment. Subjects are informed that the study compares two different injection techniques but are not told their specific group assignment.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: This is a multicenter, prospective, randomized parallel-controlled clinical trial. Eligible subjects will be randomly assigned in a 1:1 ratio to receive either upper depressor anguli oris (DAO) injection or lower DAO injection of Botulinum Toxin Type A. The efficacy and safety of the two injection regimens will be compared during a 6-month follow-up period.

Study Record Dates

• First Submitted: June 5, 2026
• First Posted: June 15, 2026
• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): December 1, 2027
• Last Updated: June 15, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will not share