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QTX-2101 and Arsenic Trioxide in Adult Patients With Acute Promyelocytic Leukemia

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical study is being done in Acute Promyelocytic Leukemia, a rare type of blood cancer. The treatment being studied is QTX-2101, taken by mouth as a capsule, and it is given together with all-trans retinoic acid, a medicine that helps leukemia cells mature into normal blood cells. The study also compares this approach with arsenic trioxide given through a vein, which is a standard treatment for this disease. The purpose of the study is to understand how well this treatment works and how safe it is.

The study is designed for adults with newly diagnosed, low-risk disease. Treatment is given in phases over time, including an early treatment period and later treatment cycles called consolidation, which are used to help keep the disease under control after the first response. During the study, blood tests, heart checks, and other routine medical checks are done, and side effects are watched closely. The study also looks at how the body handles QTX-2101 and whether the leukemia goes away to a very deep level, meaning no clear signs of the cancer marker PML/RARA can be found in the bone marrow.

The research process

The trial runs in 8 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Start of study treatment

    You enter the study after joining it and begin treatment for acute promyelocytic leukemia, which is a type of blood cancer that affects early blood cells.

    You receive qtx-2101 as 15 mg capsules taken by mouth, and you also receive all-trans retinoic acid (atra), which is a medicine used together with qtx-2101.

  2. Step 2

    Induction phase

    You take qtx-2101 by mouth at a dose of 15 mg during the induction phase, together with atra.

    The study checks whether you reach complete remission or complete remission with incomplete blood recovery. complete remission means the signs of leukemia are no longer found. complete remission with incomplete blood recovery means the leukemia is controlled, but blood counts have not fully returned to normal.

    Your blood, heart tracing, and vital signs are monitored during this period to look for side effects and treatment response.

  3. Step 3

    Consolidation cycle 1

    After induction, you continue treatment in consolidation cycle 1 with qtx-2101 15 mg by mouth and atra.

    The study continues to monitor how your body handles the medicine. this includes measuring how much of the medicine and its breakdown products are in your blood over time, which is called pharmacokinetics or pk.

  4. Step 4

    Consolidation cycle 2

    You then continue with consolidation cycle 2 using qtx-2101 15 mg by mouth and atra.

    The study continues to check for side effects, blood test changes, heart tracing changes, and changes in your vital signs.

  5. Step 5

    Consolidation cycle 3

    You then receive consolidation cycle 3 with qtx-2101 15 mg by mouth and atra.

    At the end of this cycle, the study checks whether you have molecular complete remission, which means no leukemia-related pml/rara signal is found in the bone marrow. pml/rara is a gene change linked to this type of leukemia.

    The study uses a sensitive lab test called rtqpcr (reverse transcription-polymerase chain reaction), which looks for very small amounts of the leukemia signal in the bone marrow.

  6. Step 6

    Blood level and heart tracing checks during treatment

    During treatment, blood samples are taken to measure arsenic levels and related breakdown products, including arsenious acid (asiii), arsenic acid (asv), total arsenic, dimethylarsinic acid (dma), and monomethylarsenic acid (mma).

    The study measures the highest level of the medicine in your blood, called cmax, and the total amount of medicine exposure over time, called auc.

    You have triplicate ecgs, which means three heart tracing recordings, with blood sampling done at matching times.

  7. Step 7

    Safety and outcome monitoring

    Throughout the study, the following are checked: adverse events (side effects), blood test changes, heart tracing changes, and changes in vital signs such as blood pressure, pulse, and temperature.

    The study also records how long it takes from randomization to treatment failure, relapse, or death, and it measures overall survival, which means the length of time from randomization until death from any cause.

  8. Step 8

    Patient-reported questionnaires

    During the study, you complete questionnaires about your quality of life, treatment convenience and satisfaction, health utility, and treatment burden.

    These questionnaires include eortc qlq-c30, ccsq, and eq-5d-5l.

    The study also records treatment burden by looking at the number of infusion visits, catheter use, and time spent in treatment.

Who can join the trial?

22 criteria

  • Be at least 18 years old and younger than 71 years old when signing the informed consent form, which is the written permission to join the study.
  • Be able to give written informed consent, meaning the person understands the study and signs the form voluntarily.
  • Have a diagnosis of acute promyelocytic leukemia (APL) confirmed by one of these tests:
    • t(15;17) translocation found by fluorescence in situ hybridization or cytogenetics. A translocation means parts of two chromosomes have swapped places.
    • PML/RARA gene expression found by RT-qPCR, which is a test that measures specific gene activity.
    • Have low-risk or intermediate-risk APL, meaning the white blood cell count at diagnosis was 10 × 10⁹/L or lower.
    • For Part 1 only, have low-risk APL and have already completed:
      • Induction treatment, which is the first phase of treatment.
      • 3 cycles of consolidation treatment with IV ATO and ATRA.
        • IV means given into a vein.
        • ATO is arsenic trioxide.
        • ATRA is all-trans retinoic acid.
        • Have a documented mCR at study entry, meaning a molecular complete remission, where tests show no detectable signs of the leukemia at that level.
        • For Part 2 only, have newly diagnosed low-risk APL, meaning the diagnosis is recent and treatment has not yet been completed.
        • Have enough organ function, shown by all of the following:
          • Total bilirubin of 3.0 mg/dL or lower. Bilirubin is a substance measured in blood that helps show how well the liver is working.
          • Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) at 3 times the upper limit of normal or lower. These are liver enzymes, which are proteins that can rise when the liver is stressed or injured.
          • Creatinine clearance of 30 mL/min or higher. This is a measure of kidney function.
          • Have an ECOG performance status of 2 or less, meaning the person is able to care for themselves and is not too limited in daily activities. ECOG is a scale doctors use to measure how well a person can function.
          • For females who can become pregnant, have a negative pregnancy test at the screening visit and again right before the first study treatment.
          • Be willing and able to:
            • Attend all scheduled study visits.
            • Follow the treatment plan.
            • Receive the study treatment at the study site through the end of the study period.
            • Have the required blood tests and other study procedures.
            • Follow the contraception guidance, meaning instructions to help prevent pregnancy during the study.
            • Complete the full treatment and follow-up steps unless the study doctor says stopping is medically needed.

Who cannot join the trial?

22 criteria

  • Anyone who has had ATRA treatment for more than 7 days before the first study dose, in Part 2 only. ATRA is a medicine used in this study.
  • Anyone with a past cancer that is still being treated with radiation or chemotherapy, or who has not been free of that cancer for at least 2 years before screening, except for certain allowed cancers such as localized prostate cancer treated with hormone therapy alone, breast cancer treated with hormone therapy alone, basal cell carcinoma, non-melanoma skin cancer, or cervical carcinoma in situ.
  • Anyone with an active, serious, or important uncontrolled infection that needs hospital care. An uncontrolled infection means the infection is not being kept under control.
  • Anyone with a known malabsorption syndrome or another condition that may stop the body from absorbing the study medicine properly, such as after gastrectomy (surgery to remove part or all of the stomach), or anyone who cannot swallow oral medicine.
  • Anyone with another severe short-term or long-term medical problem, mental health problem, or abnormal lab result that could raise the risk of taking part, affect the study results, or make the person unsuitable for the study.
  • Anyone with immunocompromise, meaning a weakened immune system with a higher risk of unusual infections, including people with HIV if their CD4 count is 350 cells/mm3 or less, or if they had an opportunistic infection in the last 12 months. An opportunistic infection is an infection that can happen more easily when the immune system is weak. HIV-positive people must also have been on stable antiretroviral therapy for at least 4 weeks and have an HIV viral load below 400 copies/mL before screening.
  • Anyone with active or chronic hepatitis B or active hepatitis C infection. People with past hepatitis C may still qualify only if they finished curative treatment at least 12 weeks before screening and have no detectable virus at screening.
  • Anyone who must stay on anticoagulation without interruption, such as people with a mechanical heart valve, because of a higher bleeding risk during treatment. Anticoagulation means blood-thinning medicine.
  • Pregnant females, breastfeeding females, males who will not follow the required birth control rules, or females who can become pregnant and will not follow the required birth control rules.
  • Anyone likely to stop the study after treatment or during follow-up only to join another interventional study for APL or another experimental treatment, unless the investigator or sponsor recommends it.
  • Anyone with suspected leukemia involvement in the central nervous system, which includes the brain and spinal cord.
  • Anyone with Grade 2 or higher neuropathy. Neuropathy means nerve damage that can cause pain, numbness, or weakness.
  • Anyone with a history of torsade de pointes, a dangerous type of abnormal heart rhythm.
  • Anyone with certain ECG heart test problems, including:
    • Congenital long QT syndrome, a condition present from birth that affects the heart’s electrical timing.
    • A history of, or current, serious fast heart rhythms in the upper or lower chambers of the heart.
    • Slow resting heart rate below 50 beats per minute.
    • QTc longer than 450 milliseconds on the screening ECG. QTc is a measure of how long the heart takes to recharge between beats.
    • Right bundle branch block plus left anterior hemiblock or bifascicular block, which are types of heart conduction problems.
    • Anyone with unresolved side effects from prior intravenous ATO treatment, in Part 1 only, unless those side effects are mild Grade 1 or have fully gone away before joining the study.
    • Anyone with current heart failure, or heart failure that happened within the 3 months before screening. Heart failure means the heart cannot pump blood as well as it should.
    • Anyone with a known reason they cannot take ATO or ATRA, or any ingredient in these medicines, including allergy to soy or peanut for ATRA.
    • Anyone who received another investigational agent within 30 days before screening, or within fewer than 5 half-lives after the previous investigational treatment ended, whichever is shorter. An investigational agent is a study medicine that is still being tested.
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Investigated drugs

  • QTX-2101

    is the main study treatment. It is a capsule taken by mouth and contains arsenic trioxide. In this trial, it is being tested as part of the treatment plan for newly diagnosed low-risk acute promyelocytic leukemia, to see how well it works and how safe it is.

  • Arsenic trioxide

    is the comparison treatment in the study. It is given directly into a vein as an infusion. It is used to help treat the leukemia and serves as the standard treatment the study is comparing against the oral study medicine.

  • All-trans retinoic acid

    is used together with the study treatment. It is part of the treatment combination being tested in the trial and is given to help treat the leukemia by helping the abnormal blood cells mature in a more normal way.

What is already known about the treatment

  • Arsenic trioxide Accord 1 mg/ml concentrate for solution for infusion

    This medicine is given by slow infusion into a vein in a hospital or clinic, usually by a healthcare professional, and the dose is adjusted to body weight. Arsenic trioxide is an established cancer medicine used mainly to treat acute promyelocytic leukemia, a rare type of blood cancer, and it is well described in medical literature and in current medical practice. It belongs to the group of anti-cancer medicines used for blood cancers, and it works by damaging leukemia cells and helping them mature and die, which reduces the number of abnormal cells in the blood and bone marrow.

  • QTX-2101

    This medicine is an oral capsule taken by mouth, usually swallowed whole with water as directed in the clinical trial. It is an investigational form of arsenic trioxide, so it is still being studied and is not yet a standard treatment in routine medicine, although arsenic trioxide itself is already known and widely used for acute promyelocytic leukemia. It is being developed for the same main use, treatment of this rare blood cancer, and it belongs to the anti-cancer medicine group for leukemia; at the molecular level, it acts on leukemia cells by disrupting their survival signals, helping them mature, and triggering their death.

Investigated diseases

Acute Promyelocytic Leukemia - A type of acute myeloid leukemia in which very immature white blood cells called promyelocytes build up in the bone marrow and blood. It develops when the cells stop maturing normally and begin to multiply in an uncontrolled way. The disease often progresses quickly, with the abnormal cells increasingly replacing normal blood-forming cells.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-524810-28-00Protocol codeQTX-2101-301Estimated enrolment161 patients

sourced from the EU Clinical Trials Register and site verification

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