Allergan plc conducted a clinical trial to evaluate the duration of effect and safety of Botox Cosmetic 40, 60, and 80 unit doses versus Botox Cosmetic 20 unit dose in patients with moderate to severe glabellar lines. The primary efficacy endpoint was met and was statistically significant for Botox Cosmetic 40 and 80 units versus 20 unit in 226 subjects at 24 weeks (analysis, ≥1 point improvement in Facial Wrinkle Scale (FWS) from baseline assessed by Investigator at Maximum Frown). 

Thirty-two percent of patients were responders at week 24 in the Botox Cosmetic 40 unit group, 30.6 percent in the Botox Cosmetic 60 unit group, and 38.5 percent in the Botox Cosmetic 80 unit group as compared to 16 percent in the 20 unit group. The dose effect was observed across additional outcome variables. 

For responders with a > 1 point improvement, the time to return to baseline also demonstrated a dose-effect.  The median time on the Kaplan-Meier curve was 19.7 weeks for 20 Units and 24.0 weeks for 40 Units, suggesting the median benefit of 40 units is between 20 and 24 weeks.

"These study results help us better understand the Botox Cosmetic dose duration of effect and confirm our hypothesis that higher doses of botulinum toxin produce a longer duration of treatment effect for the treatment of glabellar lines," said David Nicholson, Chief Research and Development Officer, Allergan. "Based on this data, doubling the dose of botulinum toxin extends the duration of effect to 24 weeks in approximately one-third of patients." 

The higher doses of Botox Cosmetic were safe and well tolerated. In a total 233 patients evaluable for safety, there was one serious adverse event (SAE) unrelated to treatment. Overall treatment related adverse events (AEs) compare favorably with USPI labeled AEs and no new safety signals were identified.  Across all studied doses there was 1 case (0.4%) eyelid ptosis at 80 unit and 1 case (0.4%) eyebrow ptosis at 20 unit."