A Phase 1 interventional study of deoxycytidine and deoxythymidine in Telomere Biology Disorders, Dyskeratosis Congenita and Revesz Syndrome, sponsored by Suneet Agarwal. Recruiting at 1 site in United States. Open to participants aged 1 Year to 70 Years. Per ClinicalTrials.gov, last updated 2026-08-04.
Sponsored by Suneet Agarwal · Phase 1, Interventional, and Treatment
The goal of this clinical trial is to learn if a combination therapy of deoxycytidine (dC) plus deoxythymidine (dT) is safe in patients with telomere biology disorders. The main questions it aims to answer are:
Participants will:
This is an investigator-initiated, single-arm, single-center phase 1 clinical trial investigating nucleoside therapy in patients telomere biology disorder (TBDs). TBDs are a group of rare, inherited conditions characterized by critically short telomeres which can limit cellular replication resulting in a wide spectrum of clinical manifestations. From a hematologic standpoint, patients with TBDs often present with bone marrow failure. Therapy options for bone marrow failure for patients with TBDs are limited to androgen therapy and hematopoietic cell transplantation, which are associated with significant challenges and toxicities. From a pulmonary standpoint, patients with TBDs can present with low oxygen levels due to hepatopulmonary syndrome or lung fibrosis, which requires organ transplantation. New therapeutic approaches are needed in patients with an underlying TBD. Recent studies emerging from multiple independent human genetic studies have established a critical role for deoxythymidine (dT) metabolism in human telomere maintenance and demonstrated that upregulation of nucleotide metabolism by dT supplementation in vitro led to telomere elongation. The goals of this trial are to (1) assess the safety and tolerability of enteral nucleoside therapy in patients with TBDs and (2) explore the clinical and biologic effects of enteral nucleoside therapy in patients with TBDs. A total of 36 pediatric and adult patients with a diagnosis of a TBD will be enrolled at Boston Children's Hospital. Patients will receive enteral nucleoside therapy for a total of 24 weeks. Drug diary reviews and safety and tolerability assessments will be conducted on a weekly basis during an initial dose-escalation phase (4 weeks) and then monthly until study treatment completion at week 24. Pharmacokinetic studies will be conducted on a subset of participants. Additionally, changes in lymphocyte telomere lengths, peripheral blood counts, bone marrow cellularity, clonal hematopoiesis, pulmonary function tests, and chest CT imaging may be explored pre- and post-treatment.
22 studies on the registry are indexed under Dyskeratosis Congenita; 10 are open to participants now.
This study's planned enrollment of 36 is above the median of 29 across 15 interventional studies indexed under Dyskeratosis Congenita.
Browse Dyskeratosis Congenita studies →This is the only study on the registry with Suneet Agarwal as lead sponsor.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Diagnosis requirement. Participants must meet at least one of the following requirements for a diagnosis of a telomere biology disorder:
Age-adjusted mean telomere length \< 1%ile in peripheral blood lymphocytes by flow cytometry-fluorescence in situ hybridization (flow-FISH), as reported by a Clinical Laboratory Improvement Amendments (CLIA)-approved laboratory
OR
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.
A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.
Studies often ask for 60 or 70 and above. Your doctor gives the score.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
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.
Karnofsky performance status (KPS)
A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.
Studies often ask for 60 or 70 and above. Your doctor gives the score.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
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.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
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.
Participants will take study therapy three times daily over 24 weeks with dose escalation.
Drug: deoxycytidine · Drug: deoxythymidine
Oral administration, in combination with deoxythymidine
Also known as: dC
Oral administration, in combination with deoxycytidine
Also known as: thymidine, dT
Incidence of treatment-related diarrhea [Tolerability]
Proportion of study participants with grade 3 or higher treatment-related diarrhea refractory to dose adjustments
Time frame: 8 weeks from study drug initiation
Incidence of treatment-related adverse events [Safety]
Proportion of patients with grade 3 or higher treatment-related adverse events refractory to dose adjustments
Time frame: 8 weeks from study drug initiation
Change in hemoglobin
Change in hemoglobin (in grams per deciliter)
Time frame: From pre-treatment baseline to end of treatment
Change in platelet count
Change in platelet count (in thousands of cells per microliter)
Time frame: From pre-treatment baseline to end of treatment
Change in absolute neutrophil count
Change in absolute neutrophil count (in thousands of cells per microliter)
Time frame: From pre-treatment baseline to end of treatment
Maximal plasma concentration [Cmax] of dC
Maximal plasma concentration \[Cmax\] of dC will be obtained during pharmacokinetic profiling of dC at starting dose and maximum dose in some subjects
Time frame: 24 weeks
Maximal plasma concentration [Cmax] of dT
Maximal plasma concentration \[Cmax\] of dT will be obtained during pharmacokinetic profiling of dT at starting dose and maximum dose in some subjects
Time frame: 24 weeks
Plasma half-life [T1/2] of dC
Plasma half-life \[T1/2\] of dC will be obtained during pharmacokinetic profiling of dC at starting dose and maximum dose in some subjects
Time frame: 24 weeks
Plasma half-life [T1/2] of dT
Plasma half-life \[T1/2\] of dT will be obtained during pharmacokinetic profiling of dC at starting dose and maximum dose in some subjects
Time frame: 24 weeks
Change in forced vital capacity (FVC)
Change in forced vital capacity (percent predicted) on pulmonary function testing
Time frame: Up to 24 weeks
Change in diffusing capacity of the lungs for carbon monoxide (DLCO)
Change in diffusing capacity of the lungs for carbon monoxide (percent predicted) by pulmonary function testing
Time frame: Up to 24 weeks
Plan to share: No
Started Sep 2025 (actual). Primary completion is estimated for Jun 2028, 33 months after the start.
How these figures are worked out, and which studies are left out of them.
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Studies of the drugs tested here: Deoxycytidine · Thymidine