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Small Fiber NeuropathyPhase 2NCT04153422

IVIG in the Treatment of Autoimmune Small Fiber Neuropathy With TS-HDS, FGFR-3, or Plexin D1 Antibodies

A Phase 2 study testing Panzyga IVIG in people with Small Fiber Neuropathy and Autoimmune Small Fiber Neuropathy, run by Endeavor Health at 1 site in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial summary

This study will enroll patients with small fiber neuropathy (SFN). The study will look at an intravenous immunoglobulin (IVIG) called Panzyga. Panzyga is approved by the FDA as a therapy for Primary humoral immunodeficiency (PI) in patients 2 years of age and older; Chronic immune thrombocytopenia (ITP) in adults and… Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
Panzyga IVIG
Type of treatment
Injection or infusion
Could I receive a placebo?
Yes, some participants may receive a placebo
How many people
20 participants
Where
1 siteUnited States
Study dates
15 Dec 2023to 28 Feb 2028
Phase
Phase 2
Are there results?
Not yet: the study is under way

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

  • Patients ≥ age 18
  • Patient with clinical and biopsy evidence of pure small fiber neuropathy (with or without dysautonomia) as evidenced by reduced IENFD on skin biopsy using PGP 9.5 as the immunostain. Biopsy must have been performed within 12 months of study enrollment. If biopsies were not done at CRL, they will be repeated and done at 3 sites (upper and lower thigh, lower calf), to have consistent and equivalent biopsy data with the follow up biopsy done after 6 mos of treatment
  • Patients must have elevated and/or abnormal titers of autoantibodies to TS-HDS-IgM, FGFR3-IgG, or Plexin-D1 measured by the Washington University Neuromuscular Laboratory (St Louis) within 12 mos of enrollment
  • Patients must have a baseline pain score on a visual analogue scale (VAS) of Greater or equal to 4/10
  • Patients must have a baseline Utah Early Neuropathy Scale (UENS) score of Greater or equal to 4/10
  • Small Fiber Neuropathy Screening List (SFNSL) score of 11/84 or greater
  • Non-pregnant, non-lactating female. Females of reproductive potential must use 2 forms of contraception or continuously abstain from heterosexual sex during treatment

Who cannot join

  • Any other known cause for small fiber neuropathy other than the presence of the elevated titers of TS-HDS-IgM, FGFR3-IgG, or Plexin-D1 autoantibodies
  • Patients with generalized, severe musculoskeletal conditions other than SFN that prevent a sufficient assessment of the patient by the physician
  • Electromyography/nerve conduction study (EMG/NCS) evidence of large fiber polyneuropathy, to be confirmed by study PI
  • Underlying severe heart, kidney, liver disease, or HIV infection, (Note: If there is no previous HIV test result documented within the last 5 years, a test may be performed in order to confirm eligibility)
  • Patients with a history of deep vein thrombosis within the last year prior to baseline visit or pulmonary embolism ever; patients with susceptibility to embolism or deep vein thrombosis
  • Known significant IgA deficiency with antibodies to IgA
Show all 11Show fewer
  • History of hypersensitivity, anaphylaxis or severe systemic response to immuno-globulin, blood or plasma derived products, or any component of IVIG 10%
  • Known blood hyperviscosity, or other hypercoagulable states
  • Use of IgG products within six months prior to enrollment
  • Patients with a history of drug or alcohol abuse within the past five years prior to enrollment
  • Patients unable to understand or unwilling or unable to comply with the study protocol

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

May Aunaetitrakul contact

8475702570

United States1 site, 1 recruiting
  • Endeavor Health

    Glenview, Illinois, 60026

    Anna Pham, anna.pham@endeavorhealth.org

    Recruiting

Other trials in United States

About this study

Official title: Intravenous Immunoglobulin (IVIG) in the Treatment of Small Fiber Neuropathy Due to TS-HDS, FGFR-3, or Plexin D1 Antibodies: a Double Blinded Placebo-controlled Phase II Trial

This study will enroll patients with small fiber neuropathy (SFN). The study will look at an intravenous immunoglobulin (IVIG) called Panzyga. Panzyga is approved by the FDA as a therapy for Primary humoral immunodeficiency (PI) in patients 2 years of age and older; Chronic immune thrombocytopenia (ITP) in adults and Chronic inflammatory demyelinating polyneuropathy (CIDP) in adults. It has not been approved by the FDA for use in SFN.

There is mounting evidence that Intravenous Immunoglobulin (IVIG) can cause pain reduction and improve objective nerve fiber densities on skin biopsies in great numbers in SFN patients. The primary outcome is quantified improvement in intraepidermal nerve fiber density (IENFD) on repeat skin punch biopsy after 6 months of IVIG treatment.

Read the detailed description

Small fiber neuropathy (SFN) is an increasingly prevalent diagnosis in neurology and neuromuscular centers. Modern diagnostic techniques, including skin biopsies and autonomic nervous testing are helping to find SFN in many patients with undiagnosed pain syndromes including fibromyalgia. The prevalence is rising for SFN, and an immune etiology may underlie 19%-34% of cases. While there is no standard of care treatment, current treatment strategies for SFN include long-term steroid therapy which come with a host of side effects. There is mounting evidence that Intravenous Immunoglobulin (IVIG) can cause pain reduction and improve objective nerve fiber densities on skin biopsies in great numbers in SFN patients, as well as improving validated questionnaire scores monitoring symptom burden and disability. However, neither IVIG nor any other immunosuppressant has been studied in a sufficiently powered and adequately dosed controlled, randomized clinical trial to demonstrate efficacy.

Being tested
Panzyga IVIG, Placebo
Keywords
Small Fiber Neuropathy, Neuropathy, Intravenous Immunoglobulin, IVIG, TS-HDS antibody, FGFR-3 antibody, FGFR3 antibody, Immune mediated small fiber neuropathy, Panzyga, Plexin D1 antibody
Medical subject headings
Small Fiber Neuropathy, Neuritis

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Panzyga IVIGDrug

    Immune Globulin Infusion 10% (Human)

  • PlaceboDrug

    0.9% NaCl prepared as the calculated dose equivalent volume to IVIG.

Study groups in NCT04153422
Study groupRoleWhat they receive
Treatment (IVIG)ExperimentalPatients in the treatment arm will receive 2g/kg IVIG every 4 weeks (over 2 days, 1g/kg dose on Day 1 and 1g/kg dose on Day 2) for 24 weeks (6 doses total).
Receives: Drug: Panzyga IVIG
PlaceboPlacebo comparatorPatients in the placebo arm will receive 0.9% NaCl infusions on the same schedule as the active treatment group (Day 1 and Day 2 every 4 weeks for 24 weeks total, (6 doses).
Receives: Drug: Placebo

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. quantified change in intraepidermal nerve fiber density (IENFD)

    3mm skin punch biopsy at 3 sites

    Measured: Week 24

Secondary outcomes (4)
  1. Change in visual analogue pain scale responses

    Self-reported pain intensity on a scale of 0-10 using the Wong-Baker FACES Pain Rating Scale, with 0 being no pain and 10 being pain as bad as can be

    Measured: baseline and Week 28

  2. Change in Small Fiber Neuropathy-Rasch Overall Disability Scale (SFN-RODS) score

    The SFN-RODS is a 32-item scale measuring disability in daily activities. Scores range from 0 - 64, with a lower score correlating with worse disease

    Measured: baseline and Week 28

  3. Change in Small Fiber Neuropathy-Symptom Inventory Questionnaire (SFN-SIQ) score

    The SFN-SIQ is a validated 13-item scale measuring various SFN and autonomic symptoms. Scores range from 0 -39, with a higher score correlating with more severe disease.

    Measured: baseline and Week 28

  4. Change in Utah Early Neuropathy Scale (UENS) examination scores

    The UENS is a validated physical exam score from 0-42 points to look for small fiber neuropathy. It includes measures of sensation, reflexes, and strength in both lower extremities. A higher score indicates increased impairment.

    Measured: baseline and Week 28

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted6 Nov 2019
  2. Study start15 Dec 2023
  3. Primary completion27 Aug 2027 (estimated)
  4. Study completion28 Feb 2028 (estimated)

Resources

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
Randomised
Intervention model
Parallel groups
Model description
This is a randomized, double-blind, placebo-controlled study with 10 patients in the treatment arm and 10 in the placebo arm. Patients in the treatment arm will receive 2g/kg IVIG every 4 weeks (over 2 days, 1g/kg dose on Day 1 and 1g/kg dose on Day 2) for 24 weeks (6 doses total). Patients in the placebo arm will receive 0.9% NaCl infusions on the same schedule as the active treatment group (Day 1 and Day 2 every 4 weeks for 24 weeks total, (6 doses)). All study visits will take place at Endeavor Health.
Masking
Double blind
Who is masked
Participant, Investigator
Enrolment
20 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT04153422
Sponsor's protocol ID
2025-0046
Status last verified
Aug 2025
First submitted
4 Nov 2019
Last updated
9 Jan 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
Yes
FDA-regulated device
No
Individual data sharing
No

Publications

  • Peters MJ, Bakkers M, Merkies IS, Hoeijmakers JG, van Raak EP, Faber CG. Incidence and prevalence of small-fiber neuropathy: a survey in the Netherlands. Neurology. 2013 Oct 8;81(15):1356-60. doi: 10.1212/WNL.0b013e3182a8236e. Epub 2013 Aug 30.

    PubMed 23997150
  • Antoine JC, Boutahar N, Lassabliere F, Reynaud E, Ferraud K, Rogemond V, Paul S, Honnorat J, Camdessanche JP. Antifibroblast growth factor receptor 3 antibodies identify a subgroup of patients with sensory neuropathy. J Neurol Neurosurg Psychiatry. 2015 Dec;86(12):1347-55. doi: 10.1136/jnnp-2014-309730. Epub 2015 Jan 27.

    PubMed 25628376
  • Darabi K, Abdel-Wahab O, Dzik WH. Current usage of intravenous immune globulin and the rationale behind it: the Massachusetts General Hospital data and a review of the literature. Transfusion. 2006 May;46(5):741-53. doi: 10.1111/j.1537-2995.2006.00792.x.

    PubMed 16686841
  • Singleton JR, Bixby B, Russell JW, Feldman EL, Peltier A, Goldstein J, Howard J, Smith AG. The Utah Early Neuropathy Scale: a sensitive clinical scale for early sensory predominant neuropathy. J Peripher Nerv Syst. 2008 Sep;13(3):218-27. doi: 10.1111/j.1529-8027.2008.00180.x.

    PubMed 18844788
  • Souayah N, Chin RL, Brannagan TH, Latov N, Green PH, Kokoszka A, Sander HW. Effect of intravenous immunoglobulin on cerebellar ataxia and neuropathic pain associated with celiac disease. Eur J Neurol. 2008 Dec;15(12):1300-3. doi: 10.1111/j.1468-1331.2008.02305.x.

    PubMed 19049545
  • Levine TD, Kafaie J, Zeidman LA, Saperstein DS, Massaquoi R, Bland RJ, Pestronk A. Cryptogenic small-fiber neuropathies: Serum autoantibody binding to trisulfated heparan disaccharide and fibroblast growth factor receptor-3. Muscle Nerve. 2020 Apr;61(4):512-515. doi: 10.1002/mus.26748. Epub 2019 Nov 6.

    PubMed 31650561
  • Bitzi LM, Lehnick D, Wilder-Smith EP. Small fiber neuropathy: Swiss cohort characterization. Muscle Nerve. 2021 Sep;64(3):293-300. doi: 10.1002/mus.27340. Epub 2021 Jun 16.

    PubMed 34075618
  • de Greef BTA, Hoeijmakers JGJ, Gorissen-Brouwers CML, Geerts M, Faber CG, Merkies ISJ. Associated conditions in small fiber neuropathy - a large cohort study and review of the literature. Eur J Neurol. 2018 Feb;25(2):348-355. doi: 10.1111/ene.13508. Epub 2017 Dec 18.

    PubMed 29112785
  • Fujii T, Yamasaki R, Iinuma K, Tsuchimoto D, Hayashi Y, Saitoh BY, Matsushita T, Kido MA, Aishima S, Nakanishi H, Nakabeppu Y, Kira JI. A Novel Autoantibody against Plexin D1 in Patients with Neuropathic Pain. Ann Neurol. 2018 Aug;84(2):208-224. doi: 10.1002/ana.25279. Epub 2018 Sep 3.

    PubMed 30014510
  • Gaillet A, Champion K, Lefaucheur JP, Trout H, Bergmann JF, Sene D. Intravenous immunoglobulin efficacy for primary Sjogren's Syndrome associated small fiber neuropathy. Autoimmun Rev. 2019 Nov;18(11):102387. doi: 10.1016/j.autrev.2019.102387. Epub 2019 Sep 11. No abstract available.

    PubMed 31520801
  • Goodman BP. Immunoresponsive Autonomic Neuropathy in Sjogren Syndrome-Case Series and Literature Review. Am J Ther. 2019 Jan/Feb;26(1):e66-e71. doi: 10.1097/MJT.0000000000000583.

    PubMed 28379880
  • Kovvuru S, Cardenas YC, Huttner A, Nowak RJ, Roy B. Clinical characteristics of fibroblast growth factor receptor 3 antibody-related polyneuropathy: a retrospective study. Eur J Neurol. 2020 Jul;27(7):1310-1318. doi: 10.1111/ene.14180. Epub 2020 Mar 20.

    PubMed 32068339
  • Pestronk A, Schmidt RE, Choksi RM, Sommerville RB, Al-Lozi MT. Clinical and laboratory features of neuropathies with serum IgM binding to TS-HDS. Muscle Nerve. 2012 Jun;45(6):866-72. doi: 10.1002/mus.23256.

    PubMed 22581541
  • Tavee JO, Karwa K, Ahmed Z, Thompson N, Parambil J, Culver DA. Sarcoidosis-associated small fiber neuropathy in a large cohort: Clinical aspects and response to IVIG and anti-TNF alpha treatment. Respir Med. 2017 May;126:135-138. doi: 10.1016/j.rmed.2017.03.011. Epub 2017 Mar 9.

    PubMed 28318820
  • Zeidman LA. Advances in the Management of Small Fiber Neuropathy. Neurol Clin. 2021 Feb;39(1):113-131. doi: 10.1016/j.ncl.2020.09.006. Epub 2020 Nov 7.

    PubMed 33223078

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Panzyga IVIG in people with Small Fiber Neuropathy and Autoimmune Small Fiber Neuropathy, run by Endeavor Health 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 7 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: looking for participants now, as of the sponsor's last update on 9 Jan 2026. 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. Some participants in this study may receive a placebo. 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?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Anna Pham (8475034344, anna.pham@endeavorhealth.org), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

quantified change in intraepidermal nerve fiber density (IENFD) (time frame: Week 24). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04153422, which also lists 18 linked publications.

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 9 Jan 2026.

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