Could a new drug help preserve insulin production in type 1 diabetes?

NCT ID NCT05574335

What the study statuses mean

This study's is highlighted.

Recruitment status, easiest to join first

Recruiting now
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed
The trial has finished. Results may not be published yet.
Stopped early This study
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Jun 27, 2026 · Last updated Jul 29, 2026 · Updated 2 times

Summary

This early-stage trial tested four different doses of siplizumab in 8 people aged 8–45 who were diagnosed with type 1 diabetes within the past 18 months. The goal was to find a safe dose that changes certain immune cell patterns linked to better insulin production. Participants received weekly infusions for 12 weeks and were followed for up to a year.

What this could mean

Our plain-language read of the trial. This is informational only, not medical advice or a prediction.

Active substance
siplizumab (TCD 601)
What this could lead to
If successful, this study could identify a siplizumab dosing regimen that helps preserve the body's ability to produce insulin in people newly diagnosed with type 1 diabetes.
What could go wrong
This is a very early, small trial (only 8 participants) that was terminated, so results are limited. The drug may not show meaningful benefit or could cause side effects.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 1/2

Runs two stages together: safety and dose first, then whether the treatment works.

Participants

8 people

The number who actually took part.

Started

May 2023

Finished

Oct 2025

Lead sponsor

A government research agency

The lead sponsor is the US National Institutes of Health.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

8 to 45 years

Sex

Anyone

Healthy volunteers

Not accepted

This study is not open to healthy volunteers. The entry requirements below say who it is open to.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Ability to provide informed consent (parental permission and informed assent of minor, if applicable). 2. Male or female between 8 to 45 years of age. 3. Diagnosis of T1DM within 18 months (550 days) of enrollment (V0). 4. Positive for at least one diabetes-related autoantibody, including: 1. Glutamate decarboxylase (GAD-65), 2. Insulin, if obtained within 10 days of the onset of exogenous insulin therapy, 3. Insulinoma antigen-2 (IA-2), or 4. Zinc transporter-8 (ZnT8). 5. Peak stimulated C-peptide level \> 0.15 nmol/L following a MMTT conducted ≥ 21 days from diagnosis and within 37 days of enrollment (V0). 6. Completion of a SARS-CoV-2 vaccination, according to current CDC recommendations and FDA approval(s) or emergency use authorization(s). If the participant requires administration of vaccine(s) to meet eligibility requirements, they must complete the vaccination series at least 2 weeks prior to enrollment (V0). Exclusion Criteria: 1. 1\. Use of investigational drugs within 24 weeks of participation with the exception of any vaccine for the prevention of SARS-CoV-2 infection and emergency use authorization medications for treating SARS-CoV-2. 2. Severe reaction or anaphylaxis to humanized monoclonal antibodies. 3. Inability to complete a mixed meal tolerance test: 1. History of significant allergy (e.g., anaphylaxis) to milk or soy proteins. 2. Inability to disable hybrid closed loop system. 4. History of recent (within 180 days of V0) or ongoing uncontrolled bacterial, viral, fungal or other opportunistic infections, including: 1. Human immunodeficiency virus (HIV), 2. Current or prior infection with hepatitis B (HBV), as indicated by positive HBsAg or positive HBcAb, 3. Current or prior hepatitis C (HCV), unless treated with anti-viral therapy with achievement of a sustained virologic response (undetectable viral load 12 weeks after cessation of therapy), 4. Positive QuantiFERON-TB Gold or QuantiFERON-TB Gold Plus tests. PPD or T-SPOT®.TB may be substituted for the QuantiFERON-TB Gold or QuantiFERON-TB Gold Plus tests, 5. Active infection with EBV as detected by PCR or serology at the screening visit (V-1), 6. Active infection with cytomegalovirus (CMV) as detected by PCR or serology at the screening visit (V-1), 5. Positive molecular testing of SARS-CoV-2 within 30 days of V-1. 6. Any of the following laboratory abnormalities confirmed by repeat tests at least 1 week apart: 1. White blood count (WBC) \< 3 x 103/μL;, 2. CD 3+ CD4+, T cell count below the lower limit of normal, 3. Platelet count \< 150,000 /μL, 4. Hemoglobin \< 10 g/dL, 5. ALT ≥ 2x upper limit of normal (ULN) or 6. AST ≥ 2x ULN 7. Serum creatinine \>1.5x ULN in adults or \>ULN in pediatrics. 8. Absolute lymphocyte count (ALC) below the LLN. 7. Prior or current treatment that is known to alter the natural history of T1DM or immunologic status, including high dose inhaled, extensive topical or systemic glucocorticoids. 8. Current or prior (within last 14 days of the V-1 MMTT) use of any medication known to influence glucose tolerance (e.g., atypical antipsychotics, diphenylhydantoin, thiazide, or other potassium-depleting diuretics, β-adrenergic blockers, niacin). 9. Current or prior (within the last 30 days of the V-1 MMTT) use of non-insulin medications to treat insulin resistance or elevated glucose levels. 10. Previous or current diagnosis of malignancy. 11. History of bone marrow transplantation, solid organ transplantation, or primary immunodeficiencies. 12. History or diagnoses of other autoimmune diseases with the exception of stable thyroid or celiac disease. 13. History of significant cardiovascular disease. 14. Vaccination with a live attenuated vaccine (e.g., varicella, measles, mumps, rubella, cold-attenuated intranasal influenza vaccine, bacillus Calmette- Guérin, and smallpox) within 30 days of V0. 15. Women of child-bearing potential who are unwilling to use a medically acceptable form of contraception from 14 days prior to V0 until study Week 52. 16. Women who are pregnant, lactating, or planning on pregnancy during the study. 17. Current, diagnosed mental illness (e.g., severe depression), current diagnosed or self-reported drug, or alcohol abuse that, in the opinion of the investigator, would interfere with the participant's ability to comply with study requirements. 18. Past or current medical problems or findings from physical examination or laboratory testing that are not listed above, which, in the opinion of the investigator, may pose additional risks from participation in the study, may interfere with the participant's ability to comply with study requirements or that may impact the quality or interpretation of the data obtained from the study.

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Conditions

The condition(s) this trial relates to.

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Benaroya Research Institute at Virginia Mason: Diabetes Research Program

    Seattle, Washington, 98101, United States

  • Columbia University Medical Center: Naomi Berrie Diabetes Center

    New York, New York, 10032, United States

  • University of Colorado School of Medicine: Barbara Davis Center for Diabetes

    Aurora, Colorado, 80045, United States

  • University of Iowa Children's Hospital: Department of Pediatrics, Pediatric Endocrinology and Diabetes

    Iowa City, Iowa, 52242, United States

  • University of Texas Southwestern Medical Center: Department of Internal Medicine, Division of Endocrinology

    Dallas, Texas, 75390, United States

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