A Phase 1/2 Study to Evaluate the Safety and Efficacy of Dibotatug (DR-01) in Adults With Bone Marrow Failure Syndromes (BMF)

July 14, 2026 updated by: Dren Bio

A Phase 1/2, Open-Label Study to Evaluate the Safety and Efficacy of Dibotatug in Adults With Bone Marrow Failure Syndromes

This is a multicenter, open-label, Phase 1/2 basket study to evaluate the safety and efficacy of Dibotatug (DR-01) in adults with Bone Marrow Failure syndromes.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Study DR-01-HEM-001 is an open-label Phase 1/2 study evaluating the safety and efficacy of dibotatug in adult patients with BMF syndromes. Participants will be enrolled across three cohorts. Cohort A includes relapsed Severe Aplastic Anemia participants, Cohort B includes refractory Severe Aplastic Anemia participants, and Cohort C includes relapsed or refractory transfusion dependent Nonsevere Aplastic Anemia participants. Stage 1 will evaluate the safety and preliminary efficacy in up to 12 evaluable participants, and if deemed appropriate by a Safety Review Committee, the study will continue to enroll in Stage 2 for a total of up to 60 participants.

Study Type

Interventional

Enrollment (Estimated)

60

Phase

  • Phase 2
  • Phase 1

Expanded Access

Available outside the clinical trial. See expanded access record.

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 Locations

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:

All participants must meet all of the following criteria to be included in the study:

1. Age ≥ 18 years old 2-3. Women of childbearing potential and males must agree to use 2 methods of effective contraception, with at least 1 method being highly effective.

Inclusion Criteria for Severe Aplastic Anemia (SAA) (Cohorts A and B) 4. Participants with SAA must have a current or prior diagnosis of SAA or very SAA.

Inclusion Criteria for Refractory Severe Aplastic Anemia (Cohort A) Participants with refractory SAA must have:

5. Received one ≥ 3-month course of ATG and/or CSA-based IST. 6. Refractory SAA, defined as failure to achieve CR or PR ≥ 3 months after starting ATG and/or CSA-based IST.

Inclusion Criteria for Relapsed Severe Aplastic Anemia (Cohort B) 7. Relapsed SAA, defined as relapse following a CR or PR that was achieved ≥ 3 months after starting ATG- and/or cyclosporine A (CSA)-based IST.

Inclusion Criteria for Relapsed or Refractory Transfusion-Dependent Non-Severe Aplastic Anemia (Cohort C)

Participants with RR-TD-NSAA must have:

8. Current or prior diagnosis of NSAA 9. No current or prior diagnosis of SAA. 10. Received at least 1 prior course of IST such as ATG- or CSA, with or without a TPO-R agonist (lasting ≥ 3 months).

11. Meets criteria for transfusion dependence (either RBC or platelet):

  1. RBC transfusion dependence: transfusion of ≥ 2 units of RBCs in the past 56 days
  2. Platelet transfusion dependence: transfusion of ≥ 1 unit of apheresis platelets in the past 28 days

Inclusion Criteria for Extension Treatment Period

Participants entering the Extension Treatment Period must meet the following criteria:

12. Signed informed consent form (ICF) for the Extension Treatment Period. 13. CR or PR by Week 24 during the Main Treatment Period

Exclusion Criteria:

Participants meeting any of the following criteria are ineligible to be included in the study:

  1. Diagnosis of Fanconi anemia, dyskeratosis congenita, or other congenital BMF syndrome.
  2. Prior HCT.
  3. Planning to receive HCT as treatment for AA.
  4. Evidence of a clonal disorder with poor risk cytogenetics per Revised International Prognostic Scoring System (IPSS-R) for MDS.
  5. Diagnosis of PNH or a clonal hematologic bone marrow disorder such as LGLL. Existence of PNH clones, LGLL cells, or clonal hematopoiesis of indeterminate potential (CHIP) clones without a clinical diagnosis is not exclusionary.
  6. Use of a T-cell depleting agent (e.g., ATG, alemtuzumab, thymoglobulin) within 3 months prior to Day 1.
  7. Use of a B-cell depleting agent (e.g., rituximab, ocrelizumab, ofatumumab, ublituximab) within 28 days prior to Day 1.

  8. Use of any of the following within 14 days of Day 1, unless used as an established therapy at screening and there is evidence of either progressive cytopenia or lack of count improvement over the 3 months before screening:

    1. Calcineurin inhibitor (e.g., cyclosporine)
    2. TPO-R agonist (e.g., eltrombopag)
    3. Androgen (e.g., danazol)
    4. Oral Janus kinase (JAK) inhibitor Regardless of their use as an established therapy at screening, use of the above medications is prohibited for all participants from 3 months after Day 1.

11. Current infection not adequately responding to appropriate therapy or requiring hospitalization.

12. Current uncontrolled or invasive infection with cytomegalovirus (CMV), Epstein Barr virus (EBV), varicella zoster virus (VZV), herpes simplex virus (HSV), or human T-lymphotropic virus-1 (HTLV-1), defined by polymerase chain reaction (PCR) at screening. Note that low level CMV, EBV, or VZV viremia is not exclusionary.

13. Human immunodeficiency virus (HIV) infection. 14. Current or prior infection with hepatitis B virus (HBV) 15. Current hepatitis C virus (HCV) infection 16. Latent tuberculosis (TB) infection as indicated by IFN-γ release assay without documentation of appropriate treatment (appropriate therapy as defined by the World Health Organization [WHO] and/or the United States Centers for Disease Control and Prevention).

17. Estimated glomerular filtration rate < 30 mL/min/1.73 m2 at screening (using the Chronic Kidney Disease Epidemiology Collaboration formula; Levey 2009).

18. Total bilirubin > 1.5 × upper limit of normal (ULN) (> 3 × ULN if known Gilbert's disease).

19. Aspartate aminotransferase or alanine aminotransferase > 2.5 × ULN (except in participants with known iron overload).

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Dibotatug (DR-01)
Subjects in this arm will receive 20 weeks of dosing with dibotatug. Subjects with a CR or PR by Week 24 have the option to continue dosing through Week 48; Dibotatug will be administered via IV infusion.
Drug: Dibotatug (DR-01)
Dibotatug (DR-01) administered by IV infusion

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Efficacy of dibotatug in participants with BMF syndromes
Time Frame: By 6 months
Overall response rate (complete response [CR] + partial response [PR]), as defined in disease-specific hematologic criteria
By 6 months
Safety and tolerability of dibotatug in participants with BMF syndromes
Time Frame: 52 weeks
Incidence, severity, and relationship of treatment-emergent adverse events (TEAEs), changes in clinical laboratory values, and vital signs
52 weeks

Collaborators and Investigators

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

Sponsor

Dren Bio

Investigators

  • Study Director: Wan-Jen Hong, MD, Dren Bio

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 (Estimated)

August 1, 2026

Primary Completion (Estimated)

April 1, 2029

Study Completion (Estimated)

October 1, 2030

Study Registration Dates

First Submitted

July 14, 2026

First Submitted That Met QC Criteria

July 14, 2026

First Posted (Actual)

July 17, 2026

Study Record Updates

Last Update Posted (Actual)

July 17, 2026

Last Update Submitted That Met QC Criteria

July 14, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DR-01-HEM-001

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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.

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