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: