Vocal Weakness(Post-BOTOX Injection)Phase 2NCT05123053
Firdapse for Post-BOTOX Vocal Weakness
A Phase 2 study testing Amifampridine in people with Vocal Weakness(Post-BOTOX Injection), run by Augusta University at 1 site in United States.
Trial summary
Botox injections into the thyroarytenoid muscle are a predictable and effective treatment for SD, but typically result in transient symptoms of voice weakness and breathiness during the first 2-3 weeks after injection. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Vocal Weakness(Post-BOTOX Injection)
- What is being tested?
- Amifampridine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 18 participants
- Where
- 1 siteUnited States
- Study dates
- 28 Oct 2021to 23 Sep 2025
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Male or female ≥18 years of age.
- Capable of providing informed consent.
- Confirmed physician diagnosis of spasmodic dysphonia.
- Receives onabotulinumtoxinA for treatment of their spasmodic dysphonia.
- Experiences significant breathiness ± 5 days following their injection.
- If sexually active and of childbearing potential, willing to use an acceptable method of contraception (as noted below) from screening visit until 3 months after the last dose of investigational product.
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- A.NOTE: No adequate clinical data on exposed pregnancies are available for amifampridine. No nonclinical safety data are available regarding the effects of amifampridine on reproductive function. Amifampridine phosphate should not be used during pregnancy. It is unknown whether amifampridine is excreted in human breast milk. The excretion of amifampridine in milk has not been studied in animals. Amifampridine phosphate should not be used during breastfeeding. Acceptable methods of birth control include:
- Hormonal contraception (e.g., oral contraceptive, transdermal contraceptive, contraceptive implant, or injectable hormonal contraceptive) for at least 3 months prior to study drug administration, throughout the study, and for 3 months after the last dose of study drug.
- Double-barrier birth control (e.g., a combination of male condom with either cap, diaphragm, or sponge together with spermicide) starting at the Screening visit, throughout the study, and for at least 4 weeks after the last dose of study drug. NOTE: Use of a male and female condom simultaneously is NOT an acceptable method of double-barrier birth control.
- Intrauterine contraception/device starting at the Screening visit, throughout the study, and for 3 months after the last dose of study drug.
- Total abstinence from sexual intercourse (only acceptable if it is the preferred and usual lifestyle of the subject) for at least 1 complete menstrual cycle prior to the Screening visit, throughout the study, and for 3 months after the last dose of study drug.
- Maintenance of a monogamous relationship with a male partner who has been surgically sterilized by vasectomy.
- NOTE: Periodic abstinence (calendar, symptothermal, postovulation methods), withdrawal (coitus interruptus), spermicides only, and lactational amenorrhea method are not acceptable methods of contraception.
Who cannot join
- History of epilepsy and/or on medication/treatment for seizures (such as but not limited to valproic acid, lamotrigine, topiramate, carbamazepine, and phenytoin); or, on certain medications that may lower seizure threshold, such as:
- anaesthetic drugs (propofol),
- antibiotics (penicillins, cephalosporins, imipenem),
- some antidepressants (clomipramine, bupropion, and maprotiline),
- antipsychotics (clozapine, chlorpromazine),
- bronchodilators (aminophylline, theophylline),
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- Immunomodifiers (cyclosporine), and
- Narcotic analgesics (pethidine, fentanyl).
- Any SGOT, SGPT that are more than 3x upper limit of normal; and, creatinine that is greater than 2.1
- Women who are pregnant, expecting to get pregnant, or breastfeeding.
- Any condition that, in the view of the Principal Investigator, places the subject at risk, or subjects with poor treatment compliance.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Amifampridine for the Treatment of Transient Vocal Weakness After OnabotulinumtoxinA Injection for Spasmodic Dysphonia
Botox injections into the thyroarytenoid muscle are a predictable and effective treatment for SD, but typically result in transient symptoms of voice weakness and breathiness during the first 2-3 weeks after injection. Investigators hypothesize that voice weakness and breathiness after Botox treatment can be alleviated using amifampridine.
Read the detailed description
Spasmodic dysphonia (SD) is a dystonia which results in vocal breaks. The mainstay of treatment involves injections using Botox (onabotulinumtoxinA), a neuromuscular blocker which inhibits pre-synaptic release of acetylcholine into the neuromuscular junction. Botox injections into the thyroarytenoid muscle are a predictable and effective treatment for SD, but typically result in transient symptoms of voice weakness and breathiness during the first 2-3 weeks after injection. These symptoms can be present for even longer if Botox is over- dosed.
Investigators hypothesize that these initial, transient symptoms of voice weakness and breathiness after Botox treatment can be alleviated using amifampridine which acts at the neuromuscular junction to increase synaptic presence of the neurotransmitter acetylcholine. In these initial studies, investigators will look at patients who have significant breathiness following an injection.
- Conditions
- Vocal Weakness(Post-BOTOX Injection)
- Being tested
- Amifampridine
- Keywords
- BOTOX, Onabotulinumtoxin, Spasmodic Dysphonia
- Medical subject headings
- Dysphonia
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AmifampridineDrug
Also called Firdapse
10mg tablet
| Study group | Role | What they receive |
|---|---|---|
| Treatment Arm | Experimental | subjects will be given active drug and titrated up in 10mg increments (with max single dose being 30mg) until a change or drug side effect is noticed. Receives: Drug: Amifampridine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Voice Handicap Index-10
VHI-10 is a scale used to assess the severity of problematic symptoms associated with the voice. It is a series of 10 questions. Each questions is answered using numbers 0-4, with 0 meaning the patient never has a problem with that symptom; and, 4 meaning the patient always has a problem with that symptom.
Measured: over 2 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Nov 2021
- Study start28 Oct 2021
- Primary completion27 May 2025
- Study completion23 Sep 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Vocal Weakness(Post-BOTOX Injection)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 18 participants (actual)
Sponsor and investigators
- Lead sponsor
- Augusta University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Michael H Rivner, MD, Principal investigator, Charbonnier Professor Emeritus of Neurology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05123053
- Sponsor's protocol ID
- SD-DAP-01
- Status last verified
- Feb 2025
- First submitted
- 5 Nov 2021
- Last updated
- 3 Oct 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Oct 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Amifampridine for the Treatment of Transient Vocal Weakness After OnabotulinumtoxinA Injection for Spasmodic Dysphonia
- ClinicalTrials.gov ID
- NCT05123053
- Acronym / sponsor ID
- SD-DAP-01
- Conditions
- Vocal Weakness(Post-BOTOX Injection)
- Keywords
- BOTOX, Onabotulinumtoxin, Spasmodic Dysphonia
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 18 participants (actual)
- Lead sponsor
- Augusta UniversityUniversity, hospital or other
- Study start
- 28 Oct 2021 (actual)
- Primary completion
- 27 May 2025 (actual)
- Study completion
- 23 Sep 2025 (actual)
- First posted
- 17 Nov 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Botox injections into the thyroarytenoid muscle are a predictable and effective treatment for SD, but typically result in transient symptoms of voice weakness and breathiness during the first 2-3 weeks after injection. Investigators hypothesize that voice weakness and breathiness after Botox treatment can be alleviated using amifampridine.
Detailed description
Spasmodic dysphonia (SD) is a dystonia which results in vocal breaks. The mainstay of treatment involves injections using Botox (onabotulinumtoxinA), a neuromuscular blocker which inhibits pre-synaptic release of acetylcholine into the neuromuscular junction. Botox injections into the thyroarytenoid muscle are a predictable and effective treatment for SD, but typically result in transient symptoms of voice weakness and breathiness during the first 2-3 weeks after injection. These symptoms can be present for even longer if Botox is over- dosed.
Investigators hypothesize that these initial, transient symptoms of voice weakness and breathiness after Botox treatment can be alleviated using amifampridine which acts at the neuromuscular junction to increase synaptic presence of the neurotransmitter acetylcholine. In these initial studies, investigators will look at patients who have significant breathiness following an injection.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Treatment Arm | Experimental | Drug: Amifampridinesubjects will be given active drug and titrated up in 10mg increments (with max single dose being 30mg) until a change or drug side effect is noticed. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (13 listed)
- Male or female ≥18 years of age.
- Capable of providing informed consent.
- Confirmed physician diagnosis of spasmodic dysphonia.
- Receives onabotulinumtoxinA for treatment of their spasmodic dysphonia.
- Experiences significant breathiness ± 5 days following their injection.
Key exclusion criteria (11 listed)
- History of epilepsy and/or on medication/treatment for seizures (such as but not limited to valproic acid, lamotrigine, topiramate, carbamazepine, and phenytoin); or, on certain medications that may lower seizure threshold, such as:
- Any SGOT, SGPT that are more than 3x upper limit of normal; and, creatinine that is greater than 2.1
- Women who are pregnant, expecting to get pregnant, or breastfeeding.
- Any condition that, in the view of the Principal Investigator, places the subject at risk, or subjects with poor treatment compliance.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| AmifampridineAlso: Firdapse10mg tablet | Drug | Treatment Arm |
Primary outcome
Voice Handicap Index-10
Time frame: over 2 months
VHI-10 is a scale used to assess the severity of problematic symptoms associated with the voice. It is a series of 10 questions. Each questions is answered using numbers 0-4, with 0 meaning the patient never has a problem with that symptom; and, 4 meaning the patient always has a problem with that symptom.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Oct 2025.
- Individual participant dataSharing planned: No
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Michael H Rivner, MD principal investigator
Charbonnier Professor Emeritus of Neurology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Amifampridine in people with Vocal Weakness(Post-BOTOX Injection), run by Augusta University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 13 inclusion and 11 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 3 Oct 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Voice Handicap Index-10 (time frame: over 2 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 3 Oct 2025.