Improving Neck and Jawline Aesthetics With OnabotulinumtoxinA by Minimizing Platysma Muscle Contraction Effects: Efficacy and Safety Results in a Phase 3 Randomized, Placebo-Controlled Study

Abstract

Background: Platysma prominence (PP) describes the noticeable appearance of the platysma muscle upon contraction, causing a less defined jawline contour and vertical neck bands.

Objectives: The objective of this study was to assess the safety and efficacy of onabotulinumtoxinA for improvement of PP in adults.

Methods: Participants with moderate to severe (Grade 3 to 4) PP at maximum contraction received onabotulinumtoxinA or placebo on Day 1 and were monitored for 120 days. OnabotulinumtoxinA dosage (26, 31, or 36 U) was customized based on baseline PP severity on each side of the neck.

Results: Efficacy analyses were conducted in the intent-to-treat (ITT) population (all randomized participants), and modified ITT population (mITT; psychosocially impacted by PP appearance). Results from ITT and mITT populations were comparable. As assessed by investigators, 76.7% of onabotulinumtoxinA mITT participants achieved ≥1-grade improvement vs 21.2% in the placebo group, and 41.0% vs 2.2% (P < .0001) achieved ≥2-grade improvement at Day 14. As assessed by participants, 79.9% of onabotulinumtoxinA mITT participants vs 21.8% in the placebo group and 40.8% vs 3.9% (P < .0001) achieved ≥1- or ≥2-grade improvement, respectively, at Day 14. OnabotulinumtoxinA responder rates remained higher than placebo through Day 120, gradually declining over time. OnabotulinumtoxinA participants reported significantly higher satisfaction with treatment effect, less bother from jawline and vertical neck bands, and lower psychosocial impact from PP than placebo at Day 14 (P < .0001). OnabotulinumtoxinA effectively improved self-perceived jawline definition and was well tolerated.

Conclusions: OnabotulinumtoxinA was well tolerated and effective at improving moderate to severe PP, including neck bands and jawline definition.

Figure 1.

Injection pattern diagram. The number of bands treated per side depends on the severity of the condition. Diagram initially published by Rohrich et al. Used with permission from Wolters Kluwer Health, Inc. (Waltham, MA).

Figure 2.

Participant disposition. Percentages are based on the population sample size within each box. OnabotA, onabotulinumtoxinA.

Figure 3.

Percentage of participants in the mITT population achieving at least a 2-grade improvement (A) and 1-grade improvement (B) from baseline in platysma prominence severity at maximum contraction, as assessed by investigator and participants, separately. *P < .0001 vs placebo; error bars indicate 95% confidence intervals. mITT, modified intent-to-treat; onabotA, onabotulinumtoxinA.

Figure 4.

Images illustrating the improvement in platysma prominence at maximal contraction of the platysma muscle at baseline and 14 days after treatment with onabotA. (A) A 41-year-old female participant rated independently by both clinician and participant as a Grade 4 (Severe) on both sides at baseline, who achieved a Grade 1 (Minimal) improvement on the left side (B) at Day 14 after receiving onabotA 36 U, with a follow-up of 130 days. (C) A 55-year-old female participant rated Grade 3 (Moderate) on both sides at baseline, as assessed by the investigator and participants, who achieved a Grade 1 improvement on both sides (D) at Day 14 after receiving onabotA 26 U, with a follow-up of 125 days. (E) A 30-year-old female participant with a clinician- and participant-assessed Grade 4 on both sides at baseline, who achieved a Grade 1 improvement on both sides (F) at Day 14. She was monitored for 105 days after receiving onabotA 36 U. The first 2 participants responded Very satisfied on the ANLFQ: Satisfaction (Follow-up) Item 5 at Day 14 and improved from being Somewhat bothered at Day 1 to Not at all bothered on the Bother Assessment Scale–Platysma Prominence (BAS-PP) Item 2 (jawline) and Item 1 (vertical neck bands) at Day 14. The third participant also reported being Very satisfied on the ANLFQ: Satisfaction (Follow-up) Item 5 at Day 14, and improved from being A lot bothered to Not at all bothered on the BAS-PP Items 2 and 1 at Day 14.

Figure 5.

Percentage of participants in the mITT population reporting Satisfied or Very satisfied on the Appearance of Neck and Lower Face Questionnaire (ANLFQ): Satisfaction (Follow-up) Item 5 (effect of treatment) over time. *P < .0001 vs placebo; error bars indicate 95% confidence intervals. mITT, modified intent-to-treat; onabotA, onabotulinumtoxinA.

Figure 6.

Percentage of participants in the mITT population reporting Not at all bothered or A little bothered on (A) the Bother Assessment Scale—Platysma Prominence (BAS-PP) Item 2 (jawline) and (B) Item 1 (vertical neck bands) over time. *P < .0001 vs placebo; error bars indicate 95% confidence intervals. mITT, modified intent-to-treat; onabotA, onabotulinumtoxinA.

Figure 7.

Percentage of participants in the mITT population with responses of Mild or No sagging on the Participant Global Impression of Severity (PGIS)–Jawline at all follow-up visits, among those who reported Moderate, Severe, or Extreme sagging or drooping at baseline. Error bars indicate 95% confidence intervals. mITT, modified intent-to-treat; onabotA, onabotulinumtoxinA.