Study to Evaluate of EXG34217 in Patients With Telomere Biology Disorders With Bone Marrow Failure

A Phase I/II Study to Evaluate the Safety and Tolerability of EXG34217 in Patients With Telomere Biology Disorders With Bone Marrow Failure

This is a Phase I/II, open label, single center study to assess the safety and tolerability of EXG34217 in bone marrow failure patients with telomere biology disorders.

Study Overview

• Status: Active, not recruiting
• Conditions: Bone Marrow Failure; Telomere Shortening
• Intervention / Treatment: Biological: EXG34217

Detailed Description

This is a Phase I/II, open label study in up to 12 subjects with telomere biology disorders with bone marrow failure. The study is open to all participants regardless of gender or ethnicity. Subjects who are enrolled but not evaluable will be replaced.

Subjects will sign a consent form prior to any study related procedure and will complete baseline screening assessments. Subjects for this study will not require any preparative regimen such as chemotherapy or radiation.

The study will be conducted in three parts

• Peripheral blood mononuclear cells (PBMNCs) collection; mobilization and apheresis,
• Ex vivo cell processing
• Processed cell infusion and post-infusion safety monitoring,
• Follow-up (Week 2, 3,4,5, Months 1, 2,3,4,5,6,9 and 12)

• Study Type: Interventional
• Enrollment (Estimated): 12
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Ohio
    • Cincinnati, Ohio, United States, 45229
      • Cincinnati Children's Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Child, Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 12 years and above
• Mild or moderate bone marrow failure defined by satisfying specific conditions.
• Diagnosis of telomere biology disorders

Exclusion Criteria:

• Women of child bearing potential or breastfeeding.
• Patients with cancer who are on active chemotherapeutic treatment.
• Patients with severe bone marrow failure.
• Clonal cytogenetic abnormalities associated with MDS or AML on bone marrow examination.
• Uncontrolled bacterial, viral or fungal infections.
• Prior allogeneic marrow or stem cell transplantation.
• Patients who are not eligible for G-CSF and plerixafor dosing.
• Patients who are not eligible for the apheresis.
• Patients currently taking or have taken danazol and androgens within 60 days prior to Day 1.
• Patients with any other clinically relevant acute or chronic diseases which could interfere with the patients' safety during the trial, expose them to undue risk, or which could interfere with study objectives.
• Patients who have participated in another clinical trial with an investigational drug within the previous 30 days.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: EXG34217; single autologous CD34+ cells contacted ex vivo with EXG-001	Biological: EXG34217; Single infusion

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with adverse events -Safety by Incidence of Treatment-Emergent Adverse Events	Number of participants with treatment-related adverse events as assessed by CTCAE v4.03. Incidence and nature of adverse events, vital signs, weight.	Multiple times for the duration of the study (baseline through Month 12)
Number of participants with a change in in physical examination	Physical examination changes General appearance ,Head, eyes, ears, nose, and throat, Respiratory, Cardiovascular, Musculoskeletal, Abdomen, Neurologic, Extremities, Dermatologic, Lymphatic)	Multiple times for the duration of the study (baseline through Month 12)
Number of participants with a change in Electrocardiography (ECG)	ECG (standard digital 12-lead in singlicate)	Multiple times for the duration of the study (baseline through Month 12)
Number of participants with a change in clinical laboratory evaluations	Changes in clinical laboratory evaluations (Hematology, Blood chemistry, Coagulation, and Urinalysis)	Multiple times for the duration of the study (baseline through Month 12)
Number of participants with a change of Immunogenicity	Change in Antibody against virus vector and transgene	Multiple times for the duration of the study (baseline through Month 12)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of participants with a change in telomere length	Change in telomere length in any peripheral blood cells	Screening, Month1,3,6 and 12
Number of participants with improvement of blood counts.	Blood counts: neutrophils,platelets, or hemoglobin	Multiple times for the duration of the study (baseline through Month 12)

Collaborators and Investigators

• Sponsor: Elixirgen Therapeutics, Inc.
• Investigators: Principal Investigator: Kasiani Myers, MD, Cincinnati Children Hospital Medical Center

Publications and helpful links

General Publications

• Myers KC, Davies SM, Lutzko C, Wahle R, Grier DD, Aubert G, Norris K, Baird DM, Koga M, Ko AC, Amano T, Amano M, Yu H, Ko MSH. Clinical Use of ZSCAN4 for Telomere Elongation in Hematopoietic Stem Cells. NEJM Evid. 2025 Mar;4(3):EVIDoa2400252. doi: 10.1056/EVIDoa2400252. Epub 2025 Feb 25.

Study record dates

Study Major Dates

• Study Start (Actual): April 8, 2021
• Primary Completion (Estimated): October 8, 2026
• Study Completion (Estimated): October 8, 2027

Study Registration Dates

• First Submitted: December 6, 2019
• First Submitted That Met QC Criteria: December 23, 2019
• First Posted (Actual): December 26, 2019

Study Record Updates

• Last Update Posted (Actual): February 6, 2026
• Last Update Submitted That Met QC Criteria: February 4, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Hematologic Diseases; Bone Marrow Diseases; Hemic and Lymphatic Diseases; Bone Marrow Failure Disorders
• Other Study ID Numbers: EXG-US-01

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
• product manufactured in and exported from the U.S.: No