A randomized, double-blind, placebo-controlled trial of DaxibotulinumtoxinA for Injection for the treatment of upper limb spasticity in adults after stroke or traumatic brain injury.

The enrollment was reduced to 83 randomized participants instead of the planned about 128, and the truncated sample gave 73% power to detect a 0.9-point muscle tone difference and 82% power to detect a 1-point Physician Global Impression difference. The Week 6 physician global impression co-primary endpoint was not significantly different from placebo, while the Week 4 results were post hoc supportive analyses. The placebo muscle tone change was -0.8 at Week 6 and appeared to be driven by two participants with changes of -3 and -4. The duration of effect result was based on 18 participants in the DAXI 500 U group, with a 95% confidence interval of 5.7 to more than 36 weeks. Follow-up was shorter than originally planned for some participants because of COVID-19 restrictions, and the study was designed to assess peak effect at Week 4 or 6 rather than long-term retreatment intervals. Modified Ashworth Scale measures muscle tone, not a holistic measure of the impact of treatment on patients.

Revance Therapeutics, Inc. funded the study and was involved in study design, data collection, analysis, interpretation, writing of the report, and decision to submit for publication. Writing and editorial assistance was also funded by Revance. Some authors reported support, consulting fees, honoraria, or research support from Revance and other companies, and some authors were Revance employees and shareholders.

Do not conclude that DAXI is proven effective for upper limb spasticity at all doses or that it improves function. At Week 6, the physician global impression co-primary endpoint was not significantly different from placebo, and DAXI 250 U and DAXI 375 U were not significantly better than placebo for muscle tone. The study was smaller than planned and sponsored by the manufacturer.