A First-in-Patient Study to Evaluate the Safety and Tolerability of HB-2121 as a Diagnostic for Celiac Disease

July 24, 2026 updated by: Nielsen Fernandez-Becker

The goal of this clinical trial is to learn about the safety of a single dose of HB-2121 in adults with suspected celiac disease. It will also look at how the drug affects the small intestine. The main questions it aims to answer are:

  • What side effects do participants have after receiving HB-2121?
  • How does the drug interact with the small intestine in people with suspected celiac disease?

Researchers will follow participants for 30 days after receiving HB-2121 to understand how the drug behaves in the body and how safe it is.

Participants will:

  • Receive one oral dose of HB-2121 four hours before their standard-of-care esophagogastroduodenoscopy
  • Attend 4 in-person clinic visits for checkups, lab tests, and monitoring
  • Complete 2 remote visits that include safety lab assessments
  • Fill out a short daily questionnaire for 7 days about symptoms and health status

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

20

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • California
      • Stanford, California, United States, 94305
        • Recruiting
        • Stanford University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18 to 75 years
  • Undergoing esophagogastroduodenoscopy (EGD) for suspected celiac disease
  • Body Mass Index (BMI) between 18 and 45 kg/m2
  • Creatinine < 1.5 x Upper Limit of the Normal (ULN)
  • Total bilirubin ≤ 1.5 mg/dL x (ULN)
  • Aspartate aminotransferase (AST)/Serum glutamic oxaloacetic transaminase (SGOT) & Alanine Aminotransferase (ALT)/Serum glutamic pyruvic transaminase (SGPT) ≤ 1.5 x ULN
  • Overall good health, as determined by medical history and a physical exam
  • No use of an investigational drug within 12 weeks
  • Able and willing to follow study procedures and provide written informed consent
  • If of childbearing potential, participants must agree to use highly effective birth control during the study period. The same applies to male participants with partners of childbearing potential

Exclusion Criteria:

  • Pregnant, breastfeeding, planning to become pregnant, or intending to donate eggs during the study period
  • History of cancer or malignancy
  • History of chemotherapy and/or pelvic radiation
  • History of congenital long QT syndrome or prolonged QTcF interval
  • Prisoners, institutionalized individuals, or individuals who are unable to consent for themselves
  • Known HIV infection, or positive test for hepatitis B or C, or other clinically significant chronic liver disease
  • Current use of immunosuppressant medications
  • Known allergy or sensitivity to any ingredients in the study drug
  • History of eosinophilic enteritis, Crohn's disease, or ulcerative colitis

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: 250 mg HB-2121 in Participants with Suspected Celiac Disease
Participants in this arm will receive a one-time dose of 250 mg of HB-2121.
Drug: HB-2121
HB-2121 taken once orally.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Frequency and severity of adverse events during the study window
Time Frame: From dosing through 30 days post-dose
Adverse events (AEs) will be recorded and assessed for severity using the Common Terminology Criteria for Adverse Events (CTCAE) v6.0.
From dosing through 30 days post-dose

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Intensity of sulfo-Cy5 fluorescent marker normalized to the mean fluorescence intensity of DAPI-stained nuclei in a confocal fluorescent microscopic field of view.
Time Frame: At least 120 minutes after dosing
Endoscopic biopsy samples will be collected after dosing, and fresh frozen tissue sections will be stained with DAPI and analyzed using a confocal microscope to determine the fluorescence intensity of sulfo-Cy5 and DAPI.
At least 120 minutes after dosing
Measurement of villous height to crypt depth ratio and intraepithelial lymphocyte count.
Time Frame: At least 120 minutes after dosing
Endoscopic biopsy samples will be collected after dosing, and the paraffin-embedded tissue sections will be stained with hematoxylin and eosin, as well as CD3, and analyzed using a microscope to determine villus height, crypt depth, and the number of CD3+ intraepithelial lymphocytes.
At least 120 minutes after dosing

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Frequency and identity of HB-2121 positive cells in the blood of celiac patients
Time Frame: Pre-dose, 60 minutes after dosing, and 360 minutes after dosing
Blood samples will be collected at the end of the overall endoscopic evaluation procedure, and peripheral blood mononuclear cells (PBMCs) will be analyzed using flow cytometry to determine the percentage of HB-2121+ cells among CD14+CD11c+ populations, with and without β7-integrin expression.
Pre-dose, 60 minutes after dosing, and 360 minutes after dosing
Intensity of of HB-2121-labeled ECM-associated and cellular TG2 protein in duodenal biopsy samples.
Time Frame: At least 120 minutes after dosing
Endoscopic biopsy samples will be collected after dosing, and the paraffin-embedded tissue sections will be stained with Collagen 1, PDGFRα, αSMA, CD11c, as well as DAPI, and analyzed using the confocal microscope to determine HB-2121 colocalization with ECM proteins and cell populations.
At least 120 minutes after dosing

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Nielsen Fernandez-Becker

Collaborators

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Stanford's Innovative Medicines Accelerator

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 29, 2026

Primary Completion (Estimated)

June 1, 2027

Study Completion (Estimated)

June 1, 2027

Study Registration Dates

First Submitted

January 9, 2026

First Submitted That Met QC Criteria

January 21, 2026

First Posted (Actual)

January 30, 2026

Study Record Updates

Last Update Posted (Actual)

July 28, 2026

Last Update Submitted That Met QC Criteria

July 24, 2026

Last Verified

July 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 84052

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Subscribe