A Phase 2 interventional study of Treosulfan (Treo) in HSCT, Nijmegen Breakage Syndrome and Treosulfan Based Conditioning, sponsored by Federal Research Institute of Pediatric Hematology, Oncology and Immunology. Not yet recruiting. Open to participants aged Up to 21 Years. Per ClinicalTrials.gov, last updated 2026-01-05.
Sponsored by Federal Research Institute of Pediatric Hematology, Oncology and Immunology · Phase 2, Interventional, and Treatment
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.
Federal Research Institute of Pediatric Hematology, Oncology and Immunology is the lead sponsor of 57 studies on the registry; 18 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Allogeneic and autologous transplant
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Treosulfan (Treo)
Drug: Treosulfan (Treo)
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
To evaluate event-free survival (EFS), defined by the occurrence of death, graft rejection, or development of secondary malignancy/relapse.
Event-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.
Time frame: 2 years
Overall survival
Time frame: 2 years
To evaluate the rate of transplant-associated mortality.
Time frame: 2 years
Number of Participants With Treatment-Related Adverse Events as Assessed by CTCAE v4.0
Time frame: 3 months
Probability of graft rejection
Time frame: 2 years
Frequency of Complete Donor and Mixed Chimerism after HSCT
Time frame: 1 year
Incidence of acute GVHD.
Time frame: 1 year
Incidence of chronic GVHD.
Time frame: 2 years
To assess the kinetics of immune reconstitution
Time frame: 1 year
No study locations are listed for this record.
Plan to share: No
No publications or documents are linked to this record.
Start is estimated for Dec 2025; primary completion for Dec 2028, 36 months later.
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This study is not yet recruiting, as verified in Dec 2025. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: Treosulfan
Nijmegen Breakage Syndrome
Federal Research Institute of Pediatric Hematology, Oncology and Immunology