Telomere ShorteningPhase 1NCT04211714
Study to Evaluate of EXG34217 in Patients With Telomere Biology Disorders With Bone Marrow Failure
A Phase 1 study testing EXG34217 in people with Telomere Shortening and Bone Marrow Failure, run by Elixirgen Therapeutics, Inc. at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 12 years and older
- Conditions the study is for
- Telomere Shortening, Bone Marrow Failure
- What is being tested?
- EXG34217
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteUnited States
- Study dates
- 8 Apr 2021to 8 Oct 2027
- Phase
- Phase 1
- 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 12 years and older
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Who may be able to join
- Age 12 years and above
- Mild or moderate bone marrow failure defined by satisfying specific conditions.
- Diagnosis of telomere biology disorders
Who cannot join
- 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.
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- 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.
Trial locations and contacts
1 site in 1 country.
United States1 site
Cincinnati Children's Hospital
Cincinnati, Ohio, 45229
About this study
Official title: 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.
Read the 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)
- Conditions
- Telomere Shortening, Bone Marrow Failure
- Being tested
- EXG34217
- Medical subject headings
- Bone Marrow Failure Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
EXG34217Biological
Single infusion
| Study group | Role | What they receive |
|---|---|---|
| EXG34217 | Experimental | single autologous CD34+ cells contacted ex vivo with EXG-001 Receives: Biological: EXG34217 |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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
Measured: Multiple times for the duration of the study (baseline through Month 12)
Secondary outcomes (2)
Number of participants with a change in telomere length
Change in telomere length in any peripheral blood cells
Measured: Screening, Month1,3,6 and 12
Number of participants with improvement of blood counts.
Blood counts: neutrophils,platelets, or hemoglobin
Measured: Multiple times for the duration of the study (baseline through Month 12)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Dec 2019
- Study start8 Apr 2021
- Primary completion8 Oct 2026 (estimated)
- Study completion8 Oct 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Telomere ShorteningStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
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 1
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Elixirgen Therapeutics, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Kasiani Myers, MD, Principal investigator, Cincinnati Children Hospital Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04211714
- Sponsor's protocol ID
- EXG-US-01
- Status last verified
- Feb 2026
- First submitted
- 6 Dec 2019
- Last updated
- 6 Feb 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
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.
PubMed 39998303
Study at a glance
From the registry record, last updated by the sponsor on 6 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase I/II Study to Evaluate the Safety and Tolerability of EXG34217 in Patients With Telomere Biology Disorders With Bone Marrow Failure
- ClinicalTrials.gov ID
- NCT04211714
- Acronym / sponsor ID
- EXG-US-01
- Conditions
- Telomere Shortening, Bone Marrow Failure
- Phase
- Phase 1
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- Elixirgen Therapeutics, Inc.Industry (pharma, biotech, devices)
- Study start
- 8 Apr 2021 (actual)
- Primary completion
- 8 Oct 2026 (estimated)
- Study completion
- 8 Oct 2027 (estimated)
- First posted
- 26 Dec 2019 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
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 design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| EXG34217 | Experimental | Biological: EXG34217single autologous CD34+ cells contacted ex vivo with EXG-001 |
Who may qualify
- Ages
- 12 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Key inclusion criteria (3 listed)
- Age 12 years and above
- Mild or moderate bone marrow failure defined by satisfying specific conditions.
- Diagnosis of telomere biology disorders
Key exclusion criteria (11 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| EXG34217Single infusion | Biological | EXG34217 |
Primary outcome
Number of participants with adverse events -Safety by Incidence of Treatment-Emergent Adverse Events
Time frame: Multiple times for the duration of the study (baseline through Month 12)
Number of participants with treatment-related adverse events as assessed by CTCAE v4.03. Incidence and nature of adverse events, vital signs, weight.
Number of participants with a change in in physical examination
Time frame: Multiple times for the duration of the study (baseline through Month 12)
Physical examination changes General appearance ,Head, eyes, ears, nose, and throat, Respiratory, Cardiovascular, Musculoskeletal, Abdomen, Neurologic, Extremities, Dermatologic, Lymphatic)
Number of participants with a change in Electrocardiography (ECG)
Time frame: Multiple times for the duration of the study (baseline through Month 12)
ECG (standard digital 12-lead in singlicate)
Number of participants with a change in clinical laboratory evaluations
Time frame: Multiple times for the duration of the study (baseline through Month 12)
Changes in clinical laboratory evaluations (Hematology, Blood chemistry, Coagulation, and Urinalysis)
Number of participants with a change of Immunogenicity
Time frame: Multiple times for the duration of the study (baseline through Month 12)
Change in Antibody against virus vector and transgene
2 secondary outcomes
Number of participants with a change in telomere length
Time frame: Screening, Month1,3,6 and 12
Number of participants with improvement of blood counts.
Time frame: Multiple times for the duration of the study (baseline through Month 12)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Feb 2026.
- Derived from this study: PubMed 39998303Myers 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.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Kasiani Myers, MD principal investigator
Cincinnati Children Hospital Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 1 study testing EXG34217 in people with Telomere Shortening and Bone Marrow Failure, run by Elixirgen Therapeutics, Inc. 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 3 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: under way, not looking for participants, as of the sponsor's last update on 6 Feb 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. 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 1 studies test a treatment in a small group of people for the first time or in a new way, mainly to check safety and find the right dose.
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?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Number of participants with adverse events -Safety by Incidence of Treatment-Emergent Adverse Events (time frame: Multiple times for the duration of the study (baseline through Month 12)). The study lists 5 primary outcomes in all. 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 NCT04211714, which also lists 1 linked publication.
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 6 Feb 2026.