Skip to content

KYSA-8: A Study of Anti-CD19 Chimeric Antigen Receptor T-Cell (CD19 CAR T) Therapy, in Subjects With Treatment Refractory Stiff Person Syndrome

KYSA-8: A Phase 2 Open-Label, Single-Arm, Multicenter Study of KYV-101, an Autologous Fully Human Anti-CD19 Chimeric Antigen Receptor T-Cell (CD19 CAR T) Therapy, in Subjects With Treatment Refractory Stiff Person Syndrome

Status
Active, not recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06588491
Enrollment
25
Registered
2024-09-19
Start date
2024-09-25
Completion date
2026-12-31
Last updated
2025-12-22

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Stiff-Person Syndrome, SPS

Keywords

SPS, Stiff-Person Syndrome

Brief summary

A Study of Anti-CD19 Chimeric Antigen Receptor T-Cell Therapy for Subjects with Treatment Refractory Stiff Person Syndrome

Detailed description

Stiff person syndrome (SPS) is a rare progressive immune-mediated disorder of the central nervous system (CNS) that is characterized by progressive rigidity and painful spasms of predominantly axial and proximal limb muscles. The condition gradually worsens over time and left untreated, it can lead to permanent disability and in some cases, mortality. B cells contribute to systemic autoimmunity and development of disease in several ways, most notably via cytokine production, antigen presentation and complement activation (via autoantibody production). In SPS, B cell involvement is supported by the presence of antibodies against glutamic acid decarboxylase (GAD), which is widely expressed within the CNS, catalyzing the conversion of the excitatory neurotransmitter l-glutamate to the inhibitory GABA. CAR-T therapy such as KYV-101 may be an effective treatment for SPS, by targeting these autoreactive B cells. Using chimeric antigen receptor (CAR) T-cell technology, engineered T cells with receptors are designed to recognize and eliminate B cells, including those that produce GAD autoantibodies. This approach aims to intervene at the root of the autoimmune response, offering a precise and potentially transformative treatment for SPS. CAR-T cell therapy holds promise as a targeted and effective intervention, addressing the autoimmune component directly and potentially halting disease progression.

Interventions

Standard lymphodepletion regimen

Sponsors

Kyverna Therapeutics
Lead SponsorINDUSTRY

Study design

Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE

Eligibility

Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No

Inclusion criteria

Key Inclusion Criteria: * Subject must have been diagnosed SPS per the following criteria: * Rigidity of limb and axial (trunk) muscles prominent in the abdominal and thoracolumbar paraspinal areas and making bending difficult * Clinical or electrophysiological evidence of continuous contraction of agonist and antagonist muscles * Episodic spasms precipitated by unexpected noises, tactile stimuli, or emotional upset * Absence of any other neurologic disease that could explain the stiffness and rigidity * High titer serum anti-GAD65 antibodies shown at screening -OR- seropositive for anti-glycine antibodies. If anti-GAD65 antibodies are lower than the high titer threshold peripherally but positive in the cerebrospinal fluid (CSF), the subject can be included. A prior documented high titer anti-GAD65 antibody level may be acceptable subject to sponsor review. * Active symptoms with inadequate response to at least one immunomodulatory therapy. * Stiffness index ≥2. * At least 20 of the 25 enrolled subjects should be ambulatory. Key

Exclusion criteria

* Bedridden subjects for more than 3 months. * History of CNS or spinal cord tumor, metabolic or infectious cause of myelopathy, genetically inherited progressive CNS disorder, sarcoidosis, non-SPS progressive neurologic condition or progressive multifocal leukoencephalopathy (PML). * History of stroke, seizure, dementia, Parkinson's disease, cerebellar diseases, psychosis, aphasia, and any other neurologic disorder that is of a nature and severity that the investigator considers would increase the risk for the subject. * Cardiac ejection fraction ≤ 40%.

Design outcomes

Primary

MeasureTime frameDescription
To evaluate efficacy of KYV-101Up to 12 monthsChange in the Timed 25-Foot Walk (T25-FW) from baseline
To evaluate the safety of KYV-101Up to 12 monthsIncidence of adverse events and laboratory abnormalities

Secondary

MeasureTime frameDescription
To evaluate efficacy of KYV-101Up to 12 monthsChange in Modified Rankin Scale from baseline Modified Rankin Scale: Scoring is from 0 (no symptoms) to 6 (death). A higher score indicates a worse outcome.

Other

MeasureTime frameDescription
To evaluate efficacy of KYV-101Up to 12 months6-minute walk test
To characterize the pharmacodynamics (PD)Up to 12 monthsLevels of systemic cytokine concentrations in serum
To characterize the pharmacokinetics (PK)Up to 12 monthsLevels of KYV-101 CAR-positive T cells in the blood
To evaluate the immunogenicity (humoral response) of KYV-101Up to 12 monthsPercentage of participants who develop anti-KYV-101 antibodies by immunoassays

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026