ClinicalTrials.gov record NCT06528392

Efgartigimod for Stiff Person Syndrome (ESPS)

Record copied from ClinicalTrials.gov: Oct 10, 2026AI summaries generated: Jul 27, 2026

Efgartigimod for Stiff Person Syndrome (ESPS)

StatusNot yet recruitingThe study has been registered but has not started enrolling. Sites and contacts may not be listed yet.
Study typeInterventionalA study in which researchers assign participants to one or more interventions, such as a drug, procedure, device, behavioural programme or other approach, to measure their effects.
PhasePhase 2A study that tests whether a treatment has the intended effect and continues to check safety, usually in a larger group than phase 1.
Age18 years old to 80 years old
SexAll
LocationUnited States
AI summaryWhat this study is about, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

This Phase 2, open-label study gives all participants subcutaneous efgartigimod-hyaluronidase and follows them for about 13 weeks. It enrols adults with Stiff‑Person Syndrome who have anti‑GAD antibodies. Participants come for clinic visits (up to 18) and phone calls (up to 5) for blood tests, exams, and questionnaires about stiffness, spasms, mood, and safety. The study measures stiffness and spasm scores and monitors labs, ECGs, and adverse events.

What it is studying. The study tests subcutaneous efgartigimod-hyaluronidase (EFG) in people with Stiff‑Person Syndrome to see how many have no worsening in stiffness and spasm scores while on EFG over the treatment period, and to monitor safety (laboratory values, vital signs, ECG, mood and suicide risk, and adverse events).

What the researchers hope to learn. Measure the proportion of participants without worsening in Distribution of Stiffness Index (DSI) and Heightened Sensitivity Score (HSS); quantify treatment responders (≥2 point DSI reduction and ≥1 point HSS reduction) and how long responder status is maintained; assess Modified Rankin Scale and monitor laboratory, ECG, and adverse event data.

What this study is about

The study's own summary, as published on ClinicalTrials.gov. Underlined terms have a short explanation.

The goal of this clinical trial is to examine the proportion of patients with stiff person syndrome with no worsening in stiffness and/or spasms while on efgartigimod-hyaluronidase (EFD) when compared to their current treatment. The main questions it aims to answer are:

  • proportion of patients with stiff person syndrome with no worsening in DSI and HSS scores
  • whether there are changes in laboratory values, vital signs, electrocardiogram, or depression, and suicide risk during the trial, as well as the incidence of any adverse events.

Participants will come to the clinic up to 18 times and have up to 5 phone call visits during the course of the trial. During these visits a variety of measures will be collected, including blood samples, neurological and physical exams, patient reported outcomes on stiffness, spasms, depression, and suicide risk.

Interventions being studied

Being studied in this trial does not mean the treatment or procedure is approved or available for this condition.

Biological
  • Efgartigimod

Eligibility

The criteria exactly as listed on ClinicalTrials.gov. Only the study team can say whether they apply to you.

Inclusion criteria

  • Age 18-80, men and women, capable of giving informed consent.
  • Must have unexplained stiffness of limb and axial (trunk) muscles and involuntary striated muscle spasms.
  • DSI and HHS must be >=2 (to allow for detection of improvement).
  • Presence of serum (or CSF) anti-GAD antibodies regardless of titers.
  • Stable dosage for at least two months before screening visit with antispasmodics (muscle relaxants, benzodiazepines, baclofen).
  • Women with children bearing potential must be willing to use highly effective contraception method during and for a minimum of 90 days after the last dose of IP.

Exclusion criteria

  • Exclusionary conditions:
  • 1a. type 1 DM
  • 1b. Cancer, except basal cell skin cancer
  • 1c. Infections: HIV, Hepatitis B or C, clinically significant active infection not sufficiently resolved in the investigator's opinion
  • 1d. Serum IgG (<6 g/L) at screening
  • 1e. pregnancy/breast feeding. 2. Exclusionary medications: rituximab within 6 months of screening. 3. IVIG or PLEX treatment 4 weeks prior to screening. 4. History of any type of solid organ or bone marrow transplant.

Study description and what participation involves

The registry record has no detailed description beyond the summary above.

AI summaryWhat participation may involve, in plain languageShow ▾Hide ▴

AI-written from the registry record, not the study's own wording. May contain errors or omissions. Check the registry text on this page and the original record ↗ before acting on it.

Participants receive subcutaneous efgartigimod‑hyaluronidase as the study treatment and are followed from enrollment to the end of treatment (week 13). Expect up to 18 clinic visits and up to 5 phone-call visits during the treatment period. At visits you will have blood samples taken, neurological and physical exams, vital signs and electrocardiograms, and complete questionnaires about stiffness, spasms, mood (depression) and suicide risk; the study team will monitor laboratory results and any adverse events.

How the study is structured. Phase 2, open-label interventional study with a single group: every participant receives subcutaneous efgartigimod-hyaluronidase. Participants are followed with clinic visits and phone visits over the treatment period (primary outcomes assessed through week 13). There is no randomization or masking.

Questions you could ask

These questions are suggestions for a conversation with the study team or your own clinician, not advice.

  • The registry says recruitment has not started. When is it expected to open, and can I register interest now?
  • The listed sites are in United States. Is any of them reachable for me, and does the study help with travel?
  • Which of the eligibility criteria would need to be checked with tests before I could join?

More on stiff person syndrome

Clinical trials8 trials listed for stiff person syndromeEvery trial the registry lists for stiff person syndrome, with recruitment status, phase and sites, updated from ClinicalTrials.gov.See all trials →Research updatesWhat changed in stiff person syndrome researchLatest monthly update: September 2026. Includes: Tube removal spasms. New research summarized each month in plain language, with links to every source paper.Read the latest update →

Important dates

Study start
Apr 1, 2025 (estimated)
Primary completion
Dec 31, 2026 (estimated)
Study completion
Dec 31, 2027 (estimated)
Target enrollment
10 participants (estimated)
Last updated on registry
Apr 11, 2025
Data verified
Oct 10, 2026

Sponsor and research team

The lead sponsor funds and oversees the trial. A pharmaceutical or biotech company sponsor typically means the study is testing that company's drug or device; a hospital, university, or government agency usually indicates investigator-initiated or publicly funded research.

Lead sponsor
University of South Florida

Central study contact

If you're interested in participating, the central contact can answer general questions about the study — including eligibility requirements and how to find a recruiting site near you. Actual eligibility is determined by the site's medical team.

Participating sites (1)

  • University of South Florida, Carol and Frank Morsani Center for Advanced Healthcare

    Tampa, Florida, 33612 · United States

Terms used on this page · explanations by MedicalUpdates.ai

electrocardiogram
A recording of the heart's electrical activity. QTc is one measurement from it; some drugs are avoided if it is prolonged.
adverse events
Any unwanted medical problem that happens during a study, whether or not it was caused by the treatment. A 'serious' adverse event is one that meets specific criteria, such as causing death, being life-threatening, requiring or prolonging hospital admission, causing significant disability, or another medically important outcome.
informed consent
The process of explaining a study, including its risks and what participation involves, so that a person can decide freely whether to take part. Consent is usually documented in writing, and a participant can choose to leave the study later.
before screening
The checks done before enrolment to see whether a person qualifies, such as tests, scans or a review of medical history.
highly effective contraception
Studies often ask participants who could become pregnant, or could father a child, to use contraception during the study and for a period afterwards, because the effect of the treatment on a pregnancy is unknown.
bone marrow transplant
A procedure that replaces blood-forming cells after high-dose treatment. 'Autologous' uses the person's own cells collected beforehand; 'allogeneic' uses cells from a donor.
Inclusion Criteria
The conditions a person must meet to be considered for the study, for example a confirmed diagnosis, an age range or a test result.
Exclusion Criteria
The conditions that rule a person out even if they meet the inclusion criteria, for example other illnesses, certain medicines or pregnancy.

The study record on this page is reproduced from ClinicalTrials.gov, a database of the U.S. National Library of Medicine, where it was submitted by the study sponsor. MedicalUpdates.ai does not own this content, is not affiliated with or endorsed by ClinicalTrials.gov, NIH, or the U.S. Government, and does not verify the record. Plain-language notes, the glossary and the questions above are added by this site; text in the boxes marked "AI summary" was written by an AI model and may contain errors. Registry records change over time. Check the original record for the current version and discuss eligibility or participation with a qualified healthcare professional.

← Back to clinical trials