A Phase 1/2 interventional study of DaxibotulinumtoxinA in Adductor Spasmodic Dysphonia, Voice Disorders and Spasmodic Dysphonia, sponsored by University of California, San Francisco. Completed at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-05-18.
Sponsored by University of California, San Francisco · Phase 1/2, Interventional, and Treatment
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.
132 studies on the registry are indexed under Dysphonia; 38 are open to participants now.
This study's enrollment of 22 is below the median of 30 across 87 interventional studies indexed under Dysphonia.
Browse Dysphonia studies →University of California, San Francisco is the lead sponsor of 2,169 studies on the registry; 372 are open to participants now.
Of its 267 completed or terminated interventional studies of FDA-regulated products, 202 (76%) have results posted.
Compared within Dysphonia, this study's primary condition as ClinicalTrials.gg classifies it; the registry's first condition term is Voice Disorders. The counts are of registry records indexed under each term, refreshed daily. How we classify →
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Exclusion Criteria:
exclusively having other neurologic conditions such as:
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.
Also known as: DAXI
Our Primary Outcome is the Difference in VHI-10 Score at 30 Days After Injection With DAXI.
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.
Time frame: 30 days
A Secondary Outcome Will be Comparing the Duration of Effect of DAXI With Patients' Prior Botox Treatment.
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.
Time frame: Up to 1 year
| Milestone | Administration of Daxi |
|---|---|
| Started | 22 |
| Completed | 22 |
| Not completed | 0 |
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.
| units on a scale | Administration of Daxi |
|---|---|
| Our Primary Outcome is the Difference in VHI-10 Score at 30 Days After Injection With DAXI. | 17.81 ± 8.18 |
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.
| days | Administration of Daxi |
|---|---|
| Group A (DVB DAXI>BtxA) Mean DVB for Daxi | 130.6 (34 to 179) |
| Group A (DVB DAXI>BtxA) Mean DVB for BtxA | 86.1 (51 to 111) |
| Group B (DVB DAXI=BtxA) Mean DVB for Daxi | 86.86 (69 to 118) |
| Group B (DVB DAXI=BtxA) Mean DVB for BtxA | 83.29 (70 to 111) |
| Group C (DVB DAXI<BtxA) Mean DVB for DAXI | 49.8 (37 to 66) |
| Group C (DVB DAXI<BtxA) Mean DVB for BtxA | 81.8 (52 to 92) |
Collected over from enrollment until end of follow-up, up to 6 months. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Administration of Daxi | 0/22 (0%) | 0/22 (0%) | 0/22 (0%) |
Two patients had no change in their voice and no swallowing impact. These patients were thus considered "misses," or injection events that did not reach the intended TA-LCA muscle complexes and thus were not included in the subsequent analysis.
| Age, Continuous(Years) | Administration of Daxi |
|---|---|
| Mean | 58.3 (29.6 to 75.4) |
| Sex: Female, Male(Participants) | Administration of Daxi |
|---|---|
| Female | 15 |
| Male | 5 |
| Race (NIH/OMB)(Participants) | Administration of Daxi |
|---|---|
| American Indian or Alaska Native | 0 |
| Asian | 0 |
| Native Hawaiian or Other Pacific Islander | 0 |
| Black or African American | 1 |
| White | 18 |
| More than one race | 1 |
| Unknown or Not Reported | 0 |
| VHI-10(units on a scale) | Administration of Daxi |
|---|---|
| Mean | 21.10 ± 6.82 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: No
Ran from Oct 2023 to primary completion in Mar 2025, 16 months.
Results were first posted in Mar 2026, 1 year after primary completion.
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Studies of the drug tested here: Botulinum toxin type A
University of California, San Francisco →