A Retrospective Study of Chinese-Specific Glabellar Contraction Patterns

The Relationship Between Glabellar Contraction Patterns and Glabellar Muscle Anatomy: A Magnetic Resonance Imaging-based Study

BACKGROUND

Glabellar contraction patterns were introduced to the scientific literature to help guide glabellar neuromodulator injection algorithms. However, the relationship between the underlying musculature and its influence on these glabellar contraction patterns is unclear.

OBJECTIVES

The aim of this study was to identify by magnetic resonance imaging (MRI) glabellar muscle parameters that display an influence on the distribution of individual glabellar contraction patterns.

METHODS

Thirty-four healthy young individuals of Caucasian Polish descent were investigated (17 females, 17 males) with a mean age of 23.6 years and a mean BMI of 22.8 kg/m2. MRI-based measurements of length, thickness, width, and surface area of procerus, corrugator supercilii, orbicularis oculi, and frontalis muscles were conducted.

RESULTS

Unadjusted models revealed that there was no statistically significant difference between the 5 glabellar contraction types and the investigated muscle parameters, indicating that, independent of the skin rhytid pattern, the underlying musculature was not different between the investigated groups in this sample, with all P ≥ .102. Adjusted models revealed that sex was the most influential factor, with males generally displaying higher values for the investigated parameters than females.

CONCLUSIONS

The results of this study reveal that, based on the MRI parameters investigated and the investigated cohort, there does not appear to be a strong relationship between glabellar contraction patterns and underlying glabella muscle anatomy. Utilizing glabellar contraction patterns to design neuromodulator treatment algorithms may be of variable clinical merit.

LEVEL OF EVIDENCE: 3 (THERAPEUTIC)

A Phase-III Noninferiority, Randomized Controlled Trial of Letibotulinum Toxin A for the Improvement of Moderate-to-Severe Glabellar Wrinkles in China

Background

Letibotulinum toxin A has an established efficacy and safety profile for aesthetic treatment of glabellar wrinkles. This study was conducted to demonstrate the noninferiority of letibotulinum toxin A versus onabotulinum toxin A in improving the appearance of moderate-to-severe glabellar wrinkles in Chinese patients.

Methods

This phase-III multicenter, randomized, parallel positive control, double-blinded study compared the efficacy and safety of letibotulinum toxin A and onabotulinum toxin A. Eligible participants were randomized 3:1 to receive 20 U of letibotulinum toxin A or onabotulinum toxin A and were observed for 16 weeks postinjection. The primary endpoint was noninferiority in the proportion of study participants receiving a score of 0 or 1 for glabellar wrinkles on a four-point photographic evaluation scale, as assessed by an institution evaluator at maximum frown at week 4. Secondary endpoints included assessments at rest, photographic assessment of efficacy, and subjective self-assessment of the study participants.

Results

The proportion of participants (N = 500) receiving a score of 0 or 1 at maximum frown by the institution evaluator at week 4 was 88.49% for letibotulinum toxin A and 87.39% for onabotulinum toxin A (difference, 1.10%; 95% confidence interval, -5.02 to 8.82; P = 0.7469). No significant differences were observed between the treatments for secondary efficacy or safety endpoints. Participants' self-assessment and satisfaction tended to be higher for letibotulinum toxin A than onabotulinum toxin A.

Conclusion

Letibotulinum toxin A is noninferior to onabotulinum toxin A in improving the appearance of moderate-to-severe glabellar wrinkles in Chinese patients.

Efficacy and Safety of AbobotulinumtoxinA for the Treatment of Glabellar Lines in Chinese Patients: A Pivotal, Phase 3, Randomized, Double-Blind and Open-Label Phase Study

BACKGROUND

Various botulinumtoxinA formulations are approved for glabellar lines treatment worldwide, including abobotulinumtoxinA (Dysport^®).

OBJECTIVES

Assess abobotulinumtoxinA superiority versus placebo and non-inferiority versus active comparator (onabotulinumtoxinA; Botox^®), for the treatment of Chinese patients with moderate/severe glabellar lines.

METHODS

Phase 3, randomized study (NCT02450526) comprising a double-blind (cycle 1) phase and an open-label (cycles 2-5) phase. Patients received abobotulinumtoxinA 50 units or matching placebo (5:1), active comparator (onabotulinumtoxinA 20 units) or matching placebo (5:1). In cycles 2-5, eligible patients were retreated with abobotulinumtoxinA only. Responders had glabellar lines of none/mild severity.

PRIMARY ENDPOINT

responder rates at cycle 1, day 29 at maximum frown with abobotulinumtoxinA versus placebo (for superiority; by investigator's live assessment [ILA] and subject's self-assessment [SSA]), and versus active comparator (for non-inferiority; by ILA). Treatment-emergent adverse events were recorded.

RESULTS

Overall, 520 patients were randomized. Superiority and non-inferiority, respectively, were demonstrated for abobotulinumtoxinA versus placebo (ILA, SSA; both p < 0.0001) and abobotulinumtoxinA versus active comparator. AbobotulinumtoxinA efficacy was maintained over open-label cycles; median time to onset of efficacy was 2.0 days. After 6 months, 17% of patients treated with abobotulinumtoxinA remained responders. AbobotulinumtoxinA was well-tolerated. Safety results were in line with the known profile of abobotulinumtoxinA; adverse events rate decreased with repeated treatment.

CONCLUSIONS

After a single injection, abobotulinumtoxinA demonstrated superiority versus placebo and non-inferiority versus onabotulinumtoxinA for the treatment of moderate-to-severe glabellar lines in Chinese patients. Multiple injections of abobotulinumtoxinA demonstrated efficacy and safety in the treatment of glabellar lines in Chinese patients.

LEVEL OF EVIDENCE I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .