Lower doses of Botox well-tolerated, effective for platysma prominence

Key takeaways:

• Platysma prominence treatment with 26 to 36 units of onabotulinumtoxinA was well-tolerated and had a favorable risk-benefit profile.
• Patient satisfaction was higher among those treated with onabotulinumtoxinA.

ORLANDO — Lower doses of onabotulinumtoxinA saw conferred improvements in platysma prominence at day 14 compared with placebo, according phase 3 study results presented at the American Society for Dermatologic Surgery Annual Meeting.

“Despite the potential negative impact of platysma prominence on a person’s psychosocial well-being, there is currently a lack of nonsurgical treatments available,” Sabrina Fabi, MD, of Cosmetic Laser Dermatology in San Diego, said during her presentation.

“A phase 2 dose-ranging study showed that onabotulinumtoxinA improves platysma prominence and is well-tolerated after a single treatment at doses ranging from 26 units to 72 units, although lower doses (26 U to 36 U) were associated with a more favorable safety profile,” she continued.

To further evaluate the safety and efficacy of these lower doses of onabotulinumtoxinA (Botox, AbbVie) compared with placebo, Fabi and colleagues conducted a 4-month, multicenter, double-blind, randomized, placebo-controlled phase 3 study of 408 adults (mean age, 50 years; 94% women; 90% white) with moderate (grade 3) to severe (grade 4) platysma prominence. According to investigator assessment, 23.8% of patients had bilateral moderate platysma prominence and 48.8% presented with bilateral severe platysma prominence, whereas 27.5% of patients had grade 3 on one side and grade 4 on the other.

Researchers randomly assigned participants 1:1 to receive onabotulinumtoxinA or placebo administered on day 1 of the study period into the platysma muscle. Among participants in the onabotulinumtoxinA group, those with moderate platysma prominence on both sides received 26 units of onabotulinumtoxinA, those with moderate prominence on one side and severe prominence on the other received 31 units and those with severe prominence on both sides received 36 units.

The composite primary endpoint of the study was achievement of minimal (grade 1) or mild (grade 2) platysma prominence and at least a two-grade improvement from baseline by day 14.

Overall, results showed that the rate of achieve the composite primate endpoint was “in the mid-30s” percentage of responders as assessed by investigators and participants, Fabi said. In addition, “at least 60%” of participants achieved at least a one-point improvement change to minimal or mild by day 14 according to clinician assessment, she added.

Additionally, Fabi said that “more than 60%” of participants treated with onabotulinumtoxinA reported being satisfied or very satisfied with the effect of treatment and “almost 60%” reported being less bothered by the appearance of their jawline and vertical neck bands.

The researchers noted that onabotulinumtoxinA was well-tolerated, with most treatment-related, treatment-emergent adverse events considered mild, localized to the treatment area, temporary and resolved spontaneously.

The most common treatment-related, treatment-emergent adverse events were injection site hemorrhage (onabotulinumtoxinA, 1.5%; placebo, 1.4%) and injection site bruising (onabotulinumtoxinA, 0.5%; placebo, 2.4%).

Fabi called these improvements significant and clinically meaningful, with a favorable benefit-risk profile.