DaxibotulinumtoxinA Injection for Treatment of Adductor Spasmodic Dysphonia

April 27, 2026 updated by: University of California, San Francisco

Spasmodic Dysphonia (SD) is a neurologic condition causing inappropriate contraction of the laryngeal musculature, leading to abnormal voicing. The three types (adductor, abductor, and mixed) affect varying muscle groups which produce characteristic voice patterns. The vast majority of patients with SD have adductor type, which impacts the lateral cricoarytenoid and thyroarytenoid muscle complex. While many treatment modalities have been investigated, the most effective treatment is botulinum toxin injection to these muscle groups, performed transcervically with or without electromyography (EMG) guidance. Patients undergoing this treatment typically require re-injection every 3 months. Due to its specialized nature, the laryngeal injections are not performed routinely outside of academic medical centers; thus, patients may come from a distance to receive this treatment. Both due to the significant impact on voice quality when the injections wear off and the sometimes challenging access to treatment, a longer-acting agent is desired.

Injectible daxibotuliumtoxinA (DAXI, Revance Therapeutics Inc., Newark, CA) has been shown in large clinical trials to provide safe, effective treatment for glabellar lines and cervical dystonia and may offer a longer-lasting result when compared with onabotulinumtoxinA.

Thus, a study examining the effect of DAXI for patients with adductor spasmodic dysphonia is proposed. This study aims to assess the efficacy of DAXI for transcervical laryngeal injection in patients with adductor spasmodic dysphonia.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

22

Phase

  • Phase 2
  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • San Francisco, California, United States, 94118
        • UCSF

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • greater than 18
  • diagnosis of adductor spasmodic dysphonia
  • previous successful treatment with BotoxA
  • stabilized dose for last 3 treatments

Exclusion Criteria:

  • age less than 18

  • exclusively having other neurologic conditions such as:

    • abductor spasmodic dysphonia
    • ALS
    • Multiple sclerosis
    • Parkinson's disease
    • Essential tremor

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Administration of Daxi
Injectible daxibotulinumtoxinA (DAXI, Revance Therapeutics Inc., Newark, CA) is an investigational botulinum toxin type A which has been shown in large clinical trials to provide safe, effective treatment for glabellar lines and cervical dystonia and may offer longer-lasting results when compared with onabotulinumtoxinA. Dosage will be same number of units as prior Botox A dose.
Drug: DaxibotulinumtoxinA
This is a long-acting alternative to traditional Botox A treatment.
Other Names:
  • DAXI

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Our Primary Outcome is the Difference in VHI-10 Score at 30 Days After Injection With DAXI.
Time Frame: 30 days
The Voice Handicap Index-10 (VHI-10) is a patient-reported questionnaire (range 0-40) that measures voice-related handicap, with higher scores indicating greater severity. Difference between baseline and 30 days post DAXI injection scores will be determined using a paired t-test with subjects pre-treatment VHI-10 scores as a control.
30 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
A Secondary Outcome Will be Comparing the Duration of Effect of DAXI With Patients' Prior Botox Treatment.
Time Frame: Up to 1 year
Duration of Voice Benefit (DVB) was determined by calculating the difference of time (in days) between injection date and time the patient reported a significant reduction of benefit that would prompt scheduling a repeat treatment. DVB is routinely calculated for all Adductor-type laryngeal dystonia (AdLD) patients during their return visits by asking "how many days ago did you lose injection benefit such that you felt you needed another injection." This time frame was then subtracted from the number of days between injection dates to calculate DVB. For Botox (BtxA), a mean DVB was calculated by averaging the last three DVB values from successful injections to compare to the Daxi DVB. Clinically significant difference in DVB was a priori determined as > 14 days between values to allow for normal inter-injection variability.
Up to 1 year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of California, San Francisco

Investigators

  • Principal Investigator: Clark Rosen, MD, University of California, San Francisco

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 13, 2023

Primary Completion (Actual)

March 1, 2025

Study Completion (Actual)

March 2, 2025

Study Registration Dates

First Submitted

November 19, 2021

First Submitted That Met QC Criteria

December 1, 2021

First Posted (Actual)

December 15, 2021

Study Record Updates

Last Update Posted (Actual)

May 18, 2026

Last Update Submitted That Met QC Criteria

April 27, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 21-33778

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Spasmodic Dysphonia

Clinical Trials on DaxibotulinumtoxinA

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Finland

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

Subscribe