Comparing DaxibotulinumtoxinA to OnabotulinumtoxinA for Adductor Laryngeal Dystonia: A Pilot Study

OBJECTIVES: Botulinum toxin A (BtxA) injection for AdLD is typically performed approxiamately every 3 months. DaxibotulinumtoxinA-lanm (Daxi) is a peptide-formulated neuromodulator with reported longer therapeutic duration. This study compared the safety and efficacy of Daxi to historical BtxA results in AdLD patients. METHODS: In this open-label, prospective clinical trial, 22 stable-dose, BtxA-responsive AdLD patients underwent Daxi injection. To optimize safety, the first 10 patients' doses were given in a staged fashion (3-6 days between half doses). Safety and duration of voice benefit (DVB) were the primary outcomes. PROMs and voice analyses were obtained pre- and monthly post-injection. RESULTS: Of 22 patients, 20 (75% female, mean age = 58.3) were analyzed, with two excluded for injection "misses." No adverse reactions were reported. EAT-10 showed no difference pre- and post-Daxi injection (p = 0.068). VHI-10 significantly improved (p = 0.004) pre- to post-injection. Procedural LEMG quantitative data for Daxi and BtxA were comparable (p = 0.279). DVB of Daxi was longer than BtxA in 8/20 (40%), equal to BtxA in 7/20 (35%), and shorter than BtxA in 5/19 (25%). Those with Daxi benefit had on average 43.9% (39.5 days) longer therapeutic duration than previous BtxA treatments. Seven patients (35%) returned to BtxA at subsequent injection whereas 13 patients (65%) desired repeat Daxi injection. CONCLUSION: This study represents the first implementation of Daxi for AdLD. Daxi was notably safe and effective. Although no overall significant difference was noted for the entire study cohort, 40% of patients reported substantially longer duration of voice benefit with Daxi than with BtxA, with 43.9% longer duration than their previous BtxA treatments.