A Study Investigating Intravenous Human Normal Immune Globulin 10% in Adults With Stiff Person Syndrome

NCT07552987 | Not Yet Recruiting Phase 3 DMC FDA Drug

• 1 other identifier: KB075
• Study Type: interventional
• Target: 38
• Locations: 0 countries
• Sites: N/A

Brief Summary

The purpose of this study is to evaluate the efficacy and safety of QIVIGY (Intravenous Human Normal Immune Globulin 10%) compared with placebo in adult participants with stiff person syndrome (SPS).

Conditions

Stiff Person Syndrome

Keywords

Stiff Person Syndrome; SPS; Neurological Disorders; Autoimmune Disease; Human Immunoglobulin

Outcome Measures

Primary Outcomes (1)

• Timed 25-Foot Walk (T25-FW)

  Proportion of participants showing an improvement on the Timed 25-Foot Walk

  Baseline to Week 24

Secondary Outcomes (11)

• Timed 25-Foot Walk (T25-FW)

  Baseline up to Week 48

• Distribution-of-Stiffness (DSI)

  Baseline up to Week 48

• Heightened Sensitivity Scale (HSS)

  Baseline up to Week 48

• Modified Rankin Scale (mRS)

  Baseline up to Week 48

• 9-peg Hole Test

  Baseline up to Week 48

Study Arms (2)

Kedrion IVIg 10%

EXPERIMENTAL

Participants will receive 2 g/kg IVIg 10% administered over 2-5 days at 4-week intervals for 24 weeks. Participants will have the option to enter the open label extension phase and receive IVIg 10% for 24 weeks to week 48.

Biological: Kedrion IVIg 10%

Placebo

PLACEBO COMPARATOR

Participants will receive equivalent volume of placebo administered over 2-5 days at 4-week intervals for 24 weeks. Participants will have the option to enter the open label extension phase and receive IVIg 10% for 24 weeks to week 48.

Biological: Human Albumin 5%

Interventions

Kedrion IVIg 10% BIOLOGICAL

Intravenous human normal immunoglobulin (IVIg) 10%

Also known as: QIVIGY, KIg10

Kedrion IVIg 10%

Human Albumin 5% BIOLOGICAL

Human albumin solution 5%, diluted with saline 0.9% to a final concentration of 0.5% as an intravenous infusion

Placebo

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Male or female, 18-70 years of age.
• Patient has signed the Informed Consent Form ICF).
• Diagnosed with classic SPS or SPS-plus per the following criteria:
• a. Clinical symptoms (must have 1 of 2) i. Stiffness (axial regions, limbs, or both) ii. Episodic spasms (axial regions, limbs, or both) triggered by noises, tactile stimuli, emotional stress.
• b. Clinical signs during symptomatic phase of illness (must have 1 of 3) i. Increased muscle tone (axial or limbs) ii. Exaggerated lumbar lordosis iii. Concurrent stiffness of lumbar paraspinal and abdominal muscles. c. Serological findings (must have 1 of 2) i. High-titer GAD65-IgG in the serum (e.g. ≥ 20 nmol/L by radio-immunoprecipitation assay or 10,000 IU/mL by enzyme-linked immunoassay \[ELISA\]) or any positive titer in cerebrospinal fluid \[CSF\], at the discretion of the investigator) ii. Glycine-R-IgG in serum and/or CSF by live cell binding assay. d. Patients with classic SPS must have paravertebral stiffness and torso/lower extremity predominance.
• e. Patients with SPS-plus must have one of the symptoms of brainstem and/or cerebellar dysfunction such as double vision, ataxia, or slurred speech (dysarthria).
• Distribution of stiffness index score of ≥ 2, including stiffness in the legs or trunk.
• Patient may be Ig-naïve or Ig-pre-treated, however they should not have received Ig within 3 months prior to the time of study entry (Day 0).
• Includes newly diagnosed patients
• Includes patients who have received symptomatic treatments only
• Includes patients who have failed to respond to rituximab.
• Patients who have received rituximab in the past 18 months must have B-cell reconstitution test results available from within 3 months prior to enrolment that confirms restoration of humoral immunity.
• Daily symptomatic therapy has been stable for a minimum of two weeks prior to screening and is expected to remain stable throughout the duration of the study.
• Willing to comply with all requirements of the protocol, including travel to site for scheduled protocol assessments and treatment, and completion of a diary for the study duration.
• For women of childbearing potential (WOCBP), a negative urine pregnancy test at screening, on enrollment (Day 0), and agreement to employ effective birth control measures during the study until the end of study (EOS) visit.

You may not qualify if:

• Patients incapable of giving informed consent.
• Patients with variants of SPS such as paraneoplastic or progressive encephalomyelitis with rigidity and myoclonus (PERM). Patients with pure cerebellar ataxia, ocular motor apraxia.
• Patients who are bed-bound or wheelchair-dependent.
• Ongoing/active infection with hepatitis B virus (HBV), hepatitis C virus (HCV) or HIV Type 1/2 infection. Subjects with chronic hepatitis B or hepatitis C infection currently on treatment may participate if they have undetectable viral load within 12 months of screening date.
• Patient with a history of hypersensitivity to IVIg, other injectable forms of IVIg, or to glycine (used as an excipient).
• Patient with known Immunoglobulin A (IgA) deficiency and antibodies against IgA.
• Patients who are planning to receive the following treatments within the coming 12 months, or who have received in the stated timeframe before enrollment (Day 0)
• Botulinum toxin within 6 months
• Rituximab within 6 months
• Steroid-sparing immunosuppressants (azathioprine, methotrexate, cyclophosphamide, or mycophenolate mofetil) within 1 month
• Plasmapheresis within 3 months.
• Prior chimeric antigen receptor (CAR)-T cell therapy or autologous hematopoietic stem-cell transplantation.
• Received any blood, blood product, or blood derivative within 1 month of the baseline visit.
• Had therapy with live attenuated virus vaccines within 3 months of the baseline visit.
• Use of loop diuretics within 1 week of the baseline visit.

Sponsors & Collaborators

• Kedrion S.p.A.: lead

MeSH Terms

Conditions

Stiff-Person Syndrome; Nervous System Diseases; Autoimmune Diseases

Condition Hierarchy (Ancestors)

Autoimmune Diseases of the Nervous System; Spinal Cord Diseases; Central Nervous System Diseases; Neuromuscular Diseases; Immune System Diseases

Study Officials

• Miranda Norton, PhD

  Kedrion S.p.A.

  STUDY CHAIR

Central Study Contacts

Cecilia Conz

CONTACT

+39 331 6267651; c.conz@kedrion.com

Nicola Rovai

CONTACT

+39 335 6524750; n.rovai@kedrion.com

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 17, 2026
• First Posted: April 27, 2026
• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): July 1, 2028
• Last Updated: April 27, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will not share