ClinicalTrials.gov record NCT07860021

VYVGART (Hytrulo) in Patients With Stiff Person Syndrome (SPS)

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

The Efficacy of Efgartigimod PH20 SC (VYVGART Hytrulo ) in Patients With Stiff Person Syndrome (SPS): A Double-blind, Placebo-controlled, Cross-over Trial

StatusRecruitingThe study is currently enrolling participants. Only the study team can say whether a particular person can join.
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 2/3A study that tests whether a treatment works while continuing to check safety, in a larger group than a phase 2 study alone. It combines the aims of phase 2 and phase 3 in one protocol.
Age25 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 randomized, triple-masked crossover trial tests weekly subcutaneous VYVGART (Hytrulo) versus a hyaluronidase-containing placebo in people with Stiff Person Syndrome who have had a poor or partial response to available therapies. About 26 GAD-positive patients will receive weekly doses for 12 weeks, then cross over to the other treatment for another 12 weeks; dosing will be given by a contracted home infusion company. The main outcome is change in a validated Stiffness Index; other monthly measures include time to walk 25 feet and the Modified Rankin Scale.

What it is studying. The study tests whether weekly subcutaneous efgartigimod PH20 (VYVGART Hytrulo), given for 12 weeks and compared with a hyaluronidase-containing placebo, affects stiffness, spasms, walking ability, and related clinical measures in people with GAD-positive Stiff Person Syndrome who have responded poorly to current therapies.

What the researchers hope to learn. To measure effects of VYVGART Hytrulo on the validated Stiffness Index and other clinical measures (walking time, functional status) and to determine whether it changes stiffness, spasms, gait, or quality-of-life-related outcomes in SPS patients poorly responding to current therapies.

What this study is about

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

Stiff Person Syndrome (SPS) is a rare autoimmune disorder, characterized by: a) incapacitating diffuse muscle stiffness prominent in the axial, abdominal and thoracolumbar paraspinal muscles leading to hyperlordosis, difficulty turning and bending; b) painful muscle spasms precipitated by external stimuli with difficulty performing routine daily activities; and c) slow freezing gait with frequent falls and need for walking aids leading to disability. SPS is due to impaired inhibitory GABAergic neurotransmission associated with high-titer IgG antibodies against Glutamic Acid Decarboxylase (GAD), the rate-limiting enzyme for the synthesis of the inhibitory gammaaminobutyric acid (GABA). Although SPS patients respond to IVIg based on the PI's controlled study (NEJM 2001), several patients do not improve, or their response is modest and declines over time, as documented in a longitudinal study of 36 patients followed in our Jefferson clinic; because another controlled study we performed with Rituximab was negative and SPS is a progressive disease, new therapies are needed. Efgartigimod is an FcRn inhibitor that enhances the catabolism of circulating IgG; its subcutaneous, self-administered form, HYTRULO, has been effective and FDA-approved in patients with myasthenia gravis or CIDP poorly responding to IVIg. There is evidence that patients with myasthenia who also had SPS, Hytrulo not only helped their myasthenia but the SPS also impressively improved. The present study is an investigator- initiated, double-blind, placebo controlled, cross-over, trial in 26 GAD-positive SPS patients poorly responding to available therapies. Patients will be recruited from the large number of patients seen and referred to the PI who is known for his work in SPS and has conducted the 2 previous controlled trials. Although Hytrulo is approved as selfadministered subcutaneous drug with pre-refilled syringes, in this study will be given by a contracted home infusion company once a week to ensure convenience, safety and validity. Patients will be randomized by the Jefferson Pharmacy to receiving Hytrulo or identical hyaluronidase-containing placebo for 3 months; then they will be crossed-over to placebo/Hytrulo for another 3 months. Efficacy will be based on one primary endpoint, the stiffness index, previously validated by the PI, and on two also validated secondary endpoints of time to walk and excitability index. This design provides the statistical power to objectively assess a 25-50% or greater change and objectively determine if Hytrulo offers meaningful benefits in reducing stiffness and spasms, improving gait and increasing quality of life in SPS patients poorly responding to current therapies.

Interventions being studied

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

Drug
  • VYVGART Hytrulo
  • Hytrulo-placebo (consisting of Hyaluronidase)

Eligibility

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

Inclusion criteria

  • 26 patients age 25-80 with typical SPS as per Dalakas's diagnostic criteria (1,2) poorly or partially responding to IVIg or rituximab with declining benefits, exhibiting significant symptomatology of stiffness, painful muscle spasms, and impaired walking ability will be selected. All enrolled patients will be GAD-ab or Glycin-receptor-antibody-positive and will continue receiving the non-immunosuppressive symptomatic drugs, such as diazepam, gabapentin, or baclofen.
  • All selected patients will be among the large number we currently follow in our outpatient clinic or among those being continuously referred for a second opinion or better therapies when unresponsive to current drugs.
  • All patients should be able to provide informed consent and willing to travel for scheduled protocol visits.

Exclusion criteria

  • Patients will be excluded if: a) have minimal disease, and less than 1 stiffness index; b) have very severe disease unresponsive to all therapies or non-ambulatory; and c) have paraneoplastic SPS.

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.

If you join, you will be randomly assigned in a triple-masked trial to receive either VYVGART Hytrulo or a matching placebo for 12 weeks, then cross over to the other treatment for an additional 12 weeks. Treatments are given as weekly subcutaneous doses administered by a contracted home infusion service. You will attend monthly clinic visits for assessments during the 24-week study, including the Stiffness Index, a 25-foot walk test (T25‑FW), and the Modified Rankin Scale. The registry does not state other study procedures or sample collection.

How the study is structured. Interventional treatment trial, randomized and triple-masked, with a crossover design. About 26 participants are randomly assigned to receive either VYVGART Hytrulo (1000 mg efgartigimod PH20 SC) or a matching hyaluronidase-containing placebo once weekly for 12 weeks; after 12 weeks participants switch to the other treatment for an additional 12 weeks. Monthly clinic assessments will be used to measure outcomes during each period. Doses are administered by a contracted home infusion company rather than self-administration in this study.

Questions you could ask

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

  • Some participants receive a placebo. How is that decided, and what happens for placebo-group participants when the study ends?
  • 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
Sep 30, 2026 (estimated)
Primary completion
Dec 31, 2027 (estimated)
Study completion
Jul 31, 2028 (estimated)
Target enrollment
26 participants (estimated)
Last updated on registry
Oct 6, 2026
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
Thomas Jefferson University
Principal investigator
marinos dalakas, Professor of Neurology, Director, Neuromuscular Division
Thomas Jefferson University

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)

Terms used on this page · explanations by MedicalUpdates.ai

double-blind
Two types of people involved in the study do not know which intervention a participant is receiving. The ClinicalTrials.gov record specifies who is masked, for example participants, care providers, investigators or outcome assessors.
placebo controlled
A study design in which one group receives a placebo so that the study treatment's effects can be compared with no active treatment.
cross-over
Each participant receives more than one intervention, one after the other, usually with a gap (a washout) in between. Participants act as their own comparison.
randomized
Participants are assigned to the study groups by chance, like a coin toss, rather than chosen by the doctor or the participant. This is done so the groups are comparable.
placebo
A treatment that looks like the study treatment but contains no active ingredient. Some participants receive it instead of the study treatment, usually without knowing which they got.
primary endpoint
The main result the study is designed to measure and report on. Other results, called secondary outcomes, are also collected.
endpoints
Something the study measures to judge its results, such as a symptom score, a blood test or survival. Outcomes are grouped as primary, secondary and sometimes exploratory.
immunosuppressive
A medicine that reduces the activity of the immune system. Studies of autoimmune conditions often require a stable dose, a prior failure, or a washout of such medicines.
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.
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.

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