Objectives Botulinum toxin A (BtxA) injection for AdLD is typically performed approx. 3 months. DaxibotulinumtoxinA-lamn (Daxi) is a peptide-formulated neuromodulator with reported longer therapeutic duration. This study compared 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 using manufacturers dosing conversion. To optimize safety, the first 10 patients doses were given in 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 percent 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 percent), equal to BtxA in 7/20 (35 percent), and shorter than BtxA in 5/19 (25 percent). Those with Daxi benefit had on average 43.9 percent (39.5 days) longer therapeutic duration than their previous BtxA treatments. 8 patients (36.4 percent) returned to BtxA at subsequent injection whereas 13 patients (59.1 percent) desired repeat Daxi injection.

Conclusion This study represents the first use of Daxi for AdLD. Daxi was notably safe and effective, with 40 percent of patients reporting substantive longer duration of voice benefit than with BtxA. Mean duration of voice benefit was 43.9 percent longer than their previous BtxA treatments.

The authors have declared no competing interest.

NCT05158166

Revance Therapeutics, Inc., provided free DAXXIFY and partial financial support as an Investigator Sponsored Trial; however, Revance had no input on study design, study performance or study result analysis. Study financial support also was partially provided by Dysphonia International, but Dysphonia International had no impact on study design, study performance or analysis of results.

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University of California, San Francisco IRB approval was granted prior to starting this study.

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Disclosures: Clark A. Rosen, MD- AmplioVox (Co-owner), Instrumentarium (Royalties), Medtronic (Consultant), Reflux Gourmet LLC (Shareholder) Sarah L. Schneider-MedBridge (Royalties)

Accepted for podium presentation at the American Laryngological Association meeting, New Orleans, LA, May 17, 2025

All data produced in the present work are contained in the manuscript.