Comparing <scp>DaxibotulinumtoxinA</scp> to <scp>OnabotulinumtoxinA</scp> for Adductor Laryngeal Dystonia: A Pilot Study

ABSTRACT 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. Level of Evidence 2