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.

Background: Intramuscular injection of botulinum toxin type A is a first-line pharmacotherapy for adults with upper limb spasticity (ULS). However, reemergence of symptoms within 12 weeks of treatment is common and longer-lasting treatments are needed.

Objective: To evaluate the efficacy and safety of three doses of DaxibotulinumtoxinA for Injection (DAXI) for treatment of ULS in adults with stroke or traumatic brain injury.

Intervention: Intramuscular injections of placebo (N = 24), DAXI 250 U (N = 22), DAXI 375 U (N = 19), or DAXI 500 U (N = 18) to the suprahypertonic muscle (SMG) and other muscle groups.

Design: Randomized, double-blind, placebo-controlled study.

Setting: Twenty-six study centers across the United States.

Participants: Eighty-three adult patients with ULS were randomly assigned to each treatment group and followed for up to 36 weeks.

Outcome measures: Co-primary endpoints were the Modified Ashworth Scale (MAS) score change from baseline in the designated SMG and Physician Global Impression of Change (PGIC) at Week 6.

Results: The mean changes from baseline in MAS score for the designated SMG for placebo and the DAXI 250 U, 375 U, and 500 U groups were -0.6, -0.9, -0.9, and -1.8, respectively, at Week 4 and -0.8, -0.9, -1.0, and -1.5, respectively, at Week 6. Statistically significant improvement in MAS score compared with placebo was reported only for the 500 U dose (Week 4: p < .001; Week 6: p = .049). Significant improvements in PGIC ratings compared with placebo were reported for DAXI 375 U (p = .015) and DAXI 500 U (p = .009) at Week 4 but not for any DAXI doses at Week 6. All DAXI doses were well tolerated with no trend toward more adverse events with increased dose.

Conclusion: Results from this Phase 2 study indicate that DAXI 500 U is effective and well tolerated for treatment of adults with ULS.