A Phase 1 interventional study of Arsenic Trioxide (ATO) in Low-risk Myelodysplastic Syndromes, sponsored by Groupe Francophone des Myelodysplasies. Recruiting at 3 sites in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-10.
Sponsored by Groupe Francophone des Myelodysplasies · Phase 1, Interventional, and Treatment
Phase I study with dose-escalation and expansion evaluating the safety and efficacy of oral Arsenic (ATO) in low-risk Myelodysplastic Syndromes having failed to Erythropoiesis Stimulating Agents and Luspatercept (or ineligible for the latter).
Dose escalation cohort to determine the dose limiting toxicity according to a BOIN (Bayesian optimal interval) scheme.
Patients will receive one dose of study treatment (oral Arsenic (ATO)) 5d/7 for 21 days over a 28-day cycle.
Three doses of ATO will be tested (0.10 mg/kg, 0.15 mg/kg and 0.20 mg/kg), and 9 patients will be treated at each dose.
An expansion cohort at the selected dose based on DSMB recommendations will be conducted with 6 patients, for a maximum of 15 patients included at this dose level.
Tolerability will be assessed after one treatment cycle. Response will be assessed after 3 cycles of treatment. Responders may continue study treatment until progression or limiting toxicity. Limiting toxicity is defined as any grade III/IV extra-hematological toxicity or grade IV hematological toxicity lasting more than 25 days.
If there is no response, patients will stop treatment and enter the follow-up phase of the study.
1,997 studies on the registry are indexed under Myelodysplastic Syndromes; 324 are open to participants now.
This study's planned enrollment of 24 is below the median of 40 across 1,611 interventional studies indexed under Myelodysplastic Syndromes.
Browse Myelodysplastic Syndromes studies →Groupe Francophone des Myelodysplasies is the lead sponsor of 44 studies on the registry; 5 are open to participants now.
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.
Patients must meet all the following criteria to participate in the study:
Patient with low-risk Myelodysplastic Syndromes according to Revised International Prognostic Scoring System (IPSS-R) classification (very low, low, intermediate):
A FCBP (female of ) for this study was defined as a sexually mature woman who: (1) had not undergone a hysterectomy or bilateral oophorectomy; or (2) had not been naturally (amenorrhea following cancer therapy did not rule out childbearing potential) for at least 24 consecutive months (ie, has had menses at any time in the preceding 24 consecutive months).
A FCBP participating in the study must:
If sexually active, agreed to have used, and been able to comply with, highly effective ** without interruption, 5 weeks prior to starting treatment, during treatment (including dose interruptions), and for 24 weeks after discontinuation of treatment.
Exclusion criteria:
Any patient meeting one of the following criteria cannot be included in the study:
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.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
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.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
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.
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.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
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.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
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.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
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.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Relapsed and refractory
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
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.
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.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Postmenopausal
Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).
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.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
QT and QTc
On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.
The study may name a correction formula and a limit in milliseconds, often around 450–480.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
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.
Oral Arsenic treatment
Drug: Arsenic Trioxide (ATO)
Study treatment: oral Arsenic 5d/7 for 21 days over a 28-day cycle, three doses tested (0.10 mg/kg, 0.15 mg/kg and 0.20 mg/kg). Dose escalation cohort to determine the dose limiting toxicity according to a BOIN (Bayesian optimal interval) scheme, 9 patients will be treated at each dose. An expansion cohort at the selected dose will be conducted with 6 patients. Tolerability will be assessed after one treatment cycle. Response will be assessed after 3 cycles of treatment. Responders may continue study treatment until progression or limiting toxicity. Limiting toxicity is defined as any grade III/IV extra-hematological toxicity or grade IV hematological toxicity lasting more than 25 days.
To determine the dose-limiting toxicity (DLT) of oral Arsenic (ATO)
Dose-limiting toxicity will be defined by the occurrence during the first treatment cycle of any of the following toxicities related to the trial drug (oral ATO): * Non-hematological toxicity of grade ≥ 3 * Hematological toxicity of grade ≥ 4 corresponding to a decrease of 50% or more of absolute neutrophil count (ANC) or platelet count from baseline or lower limit (if baseline was above normal), without recovery at D42 of the first cycle.
Time frame: At the end of cycle 1 (each cycle is 28 days)
To determine safety profile
Toxicities measured according to CTCAE (Common Terminology Criteria for Adverse Events)
Time frame: Through study completion, an average of 2 years
Pharmacokinetics
Measurement of the peak plasma concentration (Cmax) of oral ATO
Time frame: At the end of cycle 1 (each cycle is 28 days)
Pharmacokinetics
Measurement of area under the plasma concentration versus time curve (AUC) for oral ATO
Time frame: At the end of cycle 1 (each cycle is 28 days)
Pharmacokinetics
Measurement of the residual concentration (Cmin) of oral ATO
Time frame: At the end of cycle 1 (each cycle is 28 days)
Efficacy
Response rate (Complete Response + Partial Response + stable disease with hematological improvement according to IWG (International Working Group) 2018 criteria)
Time frame: At the end of cycle 3 (each cycle is 28 days)
Response duration
Response duration measured from date of objective response to date of relapse or progression (or date of last news in absence of event)
Time frame: Through study completion, an average of 2 years
Progression-free survival
Rate and time to transformation to high-risk myelodysplastic syndrome (MDS) or Acute Myeloid Leukemia (AML)
Time frame: Through study completion, an average of 2 years
Overall survival
Overall survival from date of inclusion to death or date of last news
Time frame: Through study completion, an average of 2 years
Plan to share: No
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Studies of the drug tested here: Arsenic Trioxide
Groupe Francophone des Myelodysplasies