Efficacy and Safety of Letibotulinumtoxin A in the Treatment of Glabellar Lines: A Randomized, Double-Blind, Multicenter, Placebo-Controlled Phase 3 Study

LetibotulinumtoxinA Attenuates the Psychological Burden of Glabellar Lines and Is Associated With High Subject Satisfaction in Phase 3 Clinical Trials

BACKGROUND

Hyperfunctional glabellar frown lines can transmit facial miscues that adversely affect emotional communication, increase perceptions of age, and diminish self-esteem.

OBJECTIVE

To evaluate the efficacy of letibotulinumtoxinA in mitigating the negative psychological impact associated with moderate to severe glabellar lines and to assess subject satisfaction with treatment outcome in the BLESS phase 3 clinical trials.

MATERIALS AND METHODS

Baseline and posttreatment assessments were made using validated subject-administered instruments: Modified Skindex-16 Glabellar Line Quality of Life (GL-QoL) Scale, Facial Assessment and Cosmetic Evaluation Questionnaire (FACE-Q) Appraisal of Lines Between Eyebrows Scale, FACE-Q Age Appraisal Visual Analog Scale, and FACE-Q Satisfaction with Outcome Scale. An integrated analysis using pooled BLESS data was conducted on these secondary end points.

RESULTS

Among enrolled and treated subjects ( N = 1,272), 85.5% had moderate to severe psychological impact at baseline. LetibotulinumtoxinA subjects experienced significant improvements compared with placebo on all measures. Mean improvement to Week 4 for the Modified Skindex-16 GL-QoL Scale overall score was -33.84 for letibotulinumtoxinA subjects compared with -1.37 for placebo subjects ( p < .001). Attenuation of psychological burden was highly correlated with improvement in glabellar line severity ( p < .0001).

CONCLUSION

LetibotulinumtoxinA significantly improved the psychosocial burden associated with glabellar lines across all trials. Treated subjects experienced improved quality of life, younger perceived age, and satisfaction with treatment outcome.

Efficacy and Safety of LetibotulinumtoxinA in the Treatment of Moderate and Severe Glabellar Lines in Females 35 to 50 Years of Age: Post Hoc Analyses of the Phase 3 Clinical Study Data

Background

Botulinum toxin type A (BoNT-A) injections continue to be widely used as a common treatment for both males and females. According to a recent survey conducted by the International Society of Plastic Aesthetic Surgeons, the majority of patients receiving these injections are females between the ages 35 and 50.

Objectives

A post hoc analysis was conducted to examine whether there were variances in the effectiveness and safety of letibotulinumtoxinA for treating vertical glabellar lines between the broader female study population and a particularly defined group of female participants aged 35 to 50.

Methods

For this post hoc analysis, data from females aged 35 to 50 were extracted and analyzed from the BLESS III study. In this Phase 3 clinical trial, 355 participants with moderate-to-severe glabella frown lines received either 20 U of letibotulinumtoxinA or a placebo. The study evaluated Glabella Line Severity (GLS) score, treatment onset, duration of effects, time to retreatment, and adverse events. A positive response was determined by achieving a GLS score of 0 or 1, as assessed by both patients and investigators, along with at least a 2-point improvement in GLS score relative to baseline at Week 4 after the injections.

Results

Composite responder rates for patients aged 35 to 50 receiving active treatment were significantly higher than for the remaining female population receiving active treatment at Weeks 1, 2, and 4. Females aged 35 to 50 showed higher rates of GLS improvement of ≥1 at Weeks 1, 2, 4, 8, 12, 16, and 20 compared with the remaining female population receiving active treatment. At Week 4, a higher percentage of females aged 35 to 50 achieved a GLS score of 0 upon maximum frowning compared with the remaining females. Females aged 35 to 50 had a shorter median time to onset of GLS improvement compared with the remaining female population. Safety assessments showed a low incidence of treatment-related adverse events in females aged 35 to 50.

Conclusions

LetibotulinumtoxinA showed significantly higher response rates in females aged 35 to 50 compared with other female patients at Weeks 1, 2, and 4. Response rates remained higher up to Week 16. The treatment demonstrated efficacy and safety in treating vertical glabellar lines in this patient group.

Level of Evidence 2

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.