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Study of Treosulfan-Based Conditioning for HSCT in Nijmegen Breakage Syndrome

A Clinical Study of the Efficacy and Safety of Conditioning With Low Doses of Treosulfan Before Allogeneic Hematopoietic Stem Cell Transplantation for Patients With Nijmegen Breakage Syndrome

Status
Not yet recruiting
Phases
Phase 2
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT07316595
Enrollment
24
Registered
2026-01-05
Start date
2025-12-30
Completion date
2030-12-31
Last updated
2026-01-05

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

HSCT, Nijmegen Breakage Syndrome, Treosulfan Based Conditioning

Brief summary

Nijmegen breakage syndrome is one of the DNA repair defect disorders. A characteristic feature of these syndromes is a predisposition to the development of malignant neoplasms. The only curative option for the combined immunodeficiency in Nijmegen breakage syndrome is allogeneic hematopoietic stem cell transplantation (HSCT). In addition to correcting the immunodeficiency, HSCT can reduce the risk of developing hematopoietic tumors. Due to the increased sensitivity of cells in patients with Nijmegen breakage syndrome to alkylating drugs, the use of standard myeloablative conditioning regimens for this disease significantly increases the risks of toxic complications and transplant-related mortality. Treosulfan is an alkylating agent that has demonstrated efficacy with comparatively low risks of toxic complications when used as part of conditioning prior to allogeneic HSCT for various diseases in patients of all age groups. There is currently experience using treosulfan in patients with Nijmegen breakage syndrome at reduced doses (21 and 30 g/m²). However, a number of questions remain unresolved. Based on our previous experience, a dose of 21 g/m² is sufficient for patients with Nijmegen breakage syndrome without a malignant disease, as it ensures good graft function (a high probability of full donor chimerism and control of the immunodeficiency). At the same time, there is reason to believe that this dose is insufficient to provide an antitumor effect from the conditioning. We are planning a multicenter study to investigate treosulfan-based conditioning in patients with Nijmegen breakage syndrome, which will stratify patients based on the presence or absence of malignant disease. Patients without a tumor will receive treosulfan at a dose of 21 g/m², and patients with a tumor will receive 30 g/m².

Interventions

We are planning a multicenter study to investigate treosulfan-based conditioning in patients with Nijmegen breakage syndrome, which will stratify patients based on the presence or absence of malignant disease. Patients without a tumor will receive treosulfan at a dose of 21 g/m², and patients with a tumor will receive 30 g/m²

Sponsors

Russian Children's Clinical Hospital of the N.I. Pirogov Russian National Research Medical University
CollaboratorUNKNOWN
Regional Children's Clinical Hospital, Yekaterinburg
CollaboratorUNKNOWN
Morozov Children's Municipal Clinical Hospital of the Moscow City Health Department State-Financed H
CollaboratorOTHER_GOV
Raisa Gorbacheva Memorial Research Institute for Pediatric Oncology, Hematology and Transplantation
CollaboratorUNKNOWN
Federal Research Institute of Pediatric Hematology, Oncology and Immunology
Lead SponsorOTHER

Study design

Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

We are planning a study to investigate treosulfan-based conditioning in patients with Nijmegen breakage syndrome, which will stratify patients based on the presence or absence of malignant disease. Patients without a tumor will receive treosulfan at a dose of 21 g/m², and patients with a tumor will receive 30 g/m².

Eligibility

Sex/Gender
ALL
Age
No minimum to 21 Years
Healthy volunteers
No

Inclusion criteria

* genetically confirmed Nijmegen breakage syndrome * availability of informed consent for study participation, signed by the patient (ages 14 to 21) and/or their legal representative (ages 0 to 18). * absence of contraindications to HSCT based on the patient's somatic status.

Exclusion criteria

* other DNA repair deficiency syndromes (both specified and unspecified)

Design outcomes

Primary

MeasureTime frameDescription
To evaluate event-free survival (EFS), defined by the occurrence of death, graft rejection, or development of secondary malignancy/relapse.2 yearsEvent-free survival in patients with Nijmegen syndrome is the primary criterion for assessing the effectiveness of HSCT. It was precisely the need to solve the problems of graft rejection, relapses of malignant diseases, and secondary tumors that became the main reasons for initiating this study.

Secondary

MeasureTime frame
To evaluate the rate of transplant-associated mortality.2 years
Number of Participants With Treatment-Related Adverse Events as Assessed by CTCAE v4.03 months
Probability of graft rejection2 years
Overall survival2 years
Incidence of acute GVHD.1 year
Incidence of chronic GVHD.2 years
To assess the kinetics of immune reconstitution1 year
Frequency of Complete Donor and Mixed Chimerism after HSCT1 year

Contacts

Primary ContactDmitry Balashov, MD, PhD
bala8@yandex.ru+7-926-579-78-17
Backup ContactAlexandra Laberko, MD, PhD
alexandra-lab@yandex.ru+7-903-299-49-58

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026