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Study of Navtemadlin for Patients with Myelofibrosis Resistant to JAK Inhibitors

Verified siteRegistered drugNo placebo
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What is this trial about?

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

This clinical trial is focused on studying a condition called myelofibrosis, which is a type of blood cancer that affects the bone marrow. The study is specifically looking at patients with primary myelofibrosis or those who have developed myelofibrosis after having other conditions like polycythemia vera or essential thrombocythemia. These patients have not responded well to a type of treatment known as Janus Kinase (JAK) inhibitors. The main goal of the study is to see how well a new treatment, called Navtemadlin (also known by its code name KRT-232), works in reducing the size of the spleen, an organ that can become enlarged in people with myelofibrosis.

Participants in the study will be randomly assigned to receive either Navtemadlin or the best available therapy, which is the most effective treatment currently available for their condition. The study will last for several weeks, and during this time, doctors will monitor the size of the spleen using imaging techniques like magnetic resonance imaging (MRI) or computed tomography (CT) scans. The study will also look at other factors, such as the symptoms experienced by participants and their need for blood transfusions.

The study aims to provide valuable information about the effectiveness of Navtemadlin in treating myelofibrosis, especially for those who have not had success with JAK inhibitors. By comparing the new treatment with existing therapies, researchers hope to find better ways to manage this challenging condition. Participants will be closely monitored throughout the study to ensure their safety and to gather important data on how the treatment affects their health.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, eligibility is confirmed based on specific criteria such as age, previous treatment history, and diagnosis of myelofibrosis.

    The study is divided into two parts: Part A and Part B, each with distinct objectives and criteria.

  2. Step 2

    Treatment assignment

    Participants are randomly assigned to receive either the investigational drug navtemadlin or the best available therapy.

    The treatment involves oral administration of navtemadlin tablets, with dosages ranging from 10 mg to 120 mg, depending on the specific treatment arm.

  3. Step 3

    Treatment administration

    Participants take the assigned medication orally as per the prescribed dosage and schedule.

    Additional medications such as danazol, peginterferon alfa-2a (administered subcutaneously), hydroxycarbamide, lenalidomide, and prednisone may be used based on individual treatment plans.

  4. Step 4

    Monitoring and assessments

    Regular monitoring is conducted to assess the response to treatment, focusing on spleen volume reduction and symptom improvement.

    Assessments include imaging tests like MRI or CT scans to measure spleen size and evaluate treatment effectiveness.

  5. Step 5

    Evaluation of outcomes

    Primary outcomes include achieving a significant reduction in spleen volume by Week 24.

    Secondary outcomes involve symptom score reduction, transfusion independence, and overall survival rates.

  6. Step 6

    Completion of study

    The study is expected to conclude by August 2025, with final evaluations conducted to determine the overall effectiveness and safety of the treatments.

Who can join the trial?

6 criteria

  • Must be an adult aged 18 years or older.
  • Must have a confirmed diagnosis of **Primary Myelofibrosis (PMF)**, **post-Polycythemia Vera Myelofibrosis (post-PV MF)**, or **post-Essential Thrombocythemia Myelofibrosis (post-ET MF)**. These are specific types of blood disorders.
  • Must have a risk level classified as high, intermediate-2, or intermediate-1 according to the **Dynamic International Prognostic System (DIPSS)**. This is a way to assess the severity of the condition.
  • Must have previously tried treatment with a **Janus Kinase (JAK) inhibitor** and it did not work or the condition returned. JAK inhibitors are a type of medication used to treat certain blood disorders.
  • Must have an **ECOG performance status** of 2 or less. This is a scale used to assess how well a person can perform daily activities, with lower numbers indicating better ability.
  • Must have **TP53 wild-type (TP53 WT)** myelofibrosis, as confirmed by a central laboratory test. This refers to a specific genetic characteristic of the disease.
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Investigated drugs

KRT 232 is a medication being studied for its potential to help people with certain types of myelofibrosis, a condition where scar tissue forms in the bone marrow and affects blood cell production. This medication is being tested in patients who have not responded well to previous treatments with Janus Kinase (JAK) inhibitors. The study aims to see if KRT 232 can reduce the size of the spleen, which is often enlarged in people with myelofibrosis.

What is already known about the treatment

KRT-232 – KRT-232 is an oral medication currently being studied in clinical trials for its potential use in treating myelofibrosis, a type of bone marrow cancer. It is specifically being tested in patients with primary or secondary myelofibrosis who have not responded to previous treatments with Janus kinase inhibitors. The drug works by targeting and inhibiting a protein that helps cancer cells survive, thereby promoting cancer cell death. KRT-232 is classified as an anti-cancer agent and is still under investigation to determine its effectiveness and safety in reducing spleen size in affected patients.

Investigated diseases

Myelofibrosis – Myelofibrosis is a rare bone marrow disorder characterized by the replacement of bone marrow with fibrous tissue, leading to severe anemia, weakness, and fatigue. It can be primary or develop secondary to other conditions like polycythemia vera or essential thrombocythemia. The disease progresses as the fibrous tissue disrupts normal blood cell production, causing an enlarged spleen and liver due to the accumulation of blood cells. Patients may experience symptoms such as night sweats, fever, and bone pain. Over time, the condition can lead to complications like bleeding or increased risk of infections. The progression of myelofibrosis varies, and it can remain stable for years or worsen rapidly.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2024-513912-89-00Protocol codeKRT-232-101Estimated enrolment447 patientsSponsorKartos Therapeutics Inc.

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