A Phase 1 interventional study of REGN17235 in Clonal Cytopenia of Undetermined Significance (CCUS) and Low-Risk Myelodysplastic Syndrome (LR-MDS), sponsored by Regeneron Pharmaceuticals. Recruiting at 2 sites in Belgium. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-27.
Sponsored by Regeneron Pharmaceuticals · Phase 1, Interventional, and Treatment
This study will test a study drug called REGN17235 (the "study drug") to see if it can help treat Clonal Cytopenia of Undetermined Significance (CCUS) and Low-Risk Myelodysplastic Syndrome (LR-MDS) with a specific genetic mutation (SF3B1 Mutation).
The study is looking at:
1,444 studies on the registry are indexed under Hematologic Neoplasms; 420 are open to participants now.
This study's planned enrollment of 52 is above the median of 46 across 1,044 interventional studies indexed under Hematologic Neoplasms.
Browse Hematologic Neoplasms studies →Regeneron Pharmaceuticals is the lead sponsor of 411 studies on the registry; 90 are open to participants now.
Of its 125 completed or terminated interventional studies of FDA-regulated products, 79 (63%) have results posted.
Counted across the registry records on this site, refreshed daily.
Key Inclusion Criteria:
Key Exclusion Criteria:
Note: Other protocol defined Inclusion/Exclusion Criteria apply
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.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
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.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
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.
GVHD (graft-versus-host disease)
After a transplant from a donor, the donor’s immune cells attack the recipient’s body, often the skin, gut or liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: REGN17235
Drug: REGN17235
Administered per the protocol
Occurrence of Treatment Emergent Adverse Events (TEAEs)
Time frame: Up to 5 years
Severity of TEAEs
Time frame: Up to 5 years
Occurrence of Serious Adverse Events (SAEs)
Time frame: Up to 5 years
Severity of SAEs
Time frame: Up to 5 years
Hematologic improvement per International Working Group (IWG) 2018
Time frame: Up to 5 years
Concentration of REGN17235 in serum
Time frame: Up to 5 years
Occurrence of Anti-Drug Antibodies (ADA) to REGN17235 in serum
Time frame: Up to 5 years
Magnitude of ADA to REGN17235 in serum
Time frame: Up to 5 years
Plan to share: Yes — All Individual Patient Data (IPD) that underlie publicly available results will be considered for sharing
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Clinical study report, Analytic code
Time frame: When Regeneron has: received marketing authorization from major health authorities (e.g., FDA, European Medicines Agency (EMA), Pharmaceuticals and Medical Devices Agency (PMDA), etc.) for the product and indication or has globally discontinued development of the product for all indications on or after April 2020 and has no plans for future development made the study results publicly available (e.g., scientific publication, scientific conference, clinical trial registry) the legal authority to share the data, and ensured the ability to protect participant privacy
Access criteria: Qualified researchers can submit a proposal for access to individual patient or aggregate level data from a Regeneron-sponsored clinical trial through Vivli. Regeneron's Independent Research Request Evaluation Criteria can be found at: https://www.regeneron.com/sites/default/files/Regeneron-External-Data-Sharing-Policy-and-Independent-Research-Request-Evaluation-Criteria.pdf
Data sharing details ↗ · vivli.org
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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