KRT-232 in Subjects With PMF, Post-PV MF, or Post-ET MF Who Have Failed a JAK Inhibitor
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ClinicalTrials.gov Identifier: NCT03662126 |
Recruitment Status :
Recruiting
First Posted : September 7, 2018
Last Update Posted : November 26, 2019
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This study evaluates KRT-232, a novel oral small molecule inhibitor of MDM2, for the treatment of patients with myelofibrosis (MF) who no longer benefit from treatment with JAK inhibitor. Inhibition of MDM2 is a novel mechanism of action in MF.
This study is a global, open-label Phase 2 study to determine the efficacy and safety of KRT-232 in patients with primary MF, post-polycythemia vera MF, or post-essential thrombocythemia MF who have failed previous treatment with JAK inhibitor (Part A), or Ruxolitinib (Part B). In Part A of the study, patients will be randomly assigned to 2 different doses and 3 different dosing schedules of KRT-232. In Part B of the study, patients will be treated at the recommended dose and schedule from Part A.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Primary Myelofibrosis (PMF) Post-Polycythemia Vera MF (Post-PV-MF) Post-Essential Thrombocythemia MF (Post-ET-MF) | Drug: KRT-232 | Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 203 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | An Open-Label, Phase 2a/2b Study of KRT-232 in Subjects With Primary Myelofibrosis (PMF), Post-Polycythemia Vera MF (Post-PV-MF), Or Post-Essential Thrombocythemia MF (Post-ET-MF) Who Have Failed a JAK Inhibitor |
Actual Study Start Date : | January 15, 2019 |
Estimated Primary Completion Date : | August 1, 2021 |
Estimated Study Completion Date : | February 28, 2023 |

Arm | Intervention/treatment |
---|---|
Experimental: Part A Cohort 1
KRT-232 120mg by mouth once daily for Days 1-7, off treatment for Days 8-21 (21-day cycles)
|
Drug: KRT-232
KRT-232, administered by mouth |
Experimental: Part A Cohort 2
KRT-232 240mg by mouth once daily for Days 1-7, off treatment for Days 8-21 (21-day cycles)
|
Drug: KRT-232
KRT-232, administered by mouth |
Experimental: Part A Cohort 3
KRT-232 240mg by mouth once daily for Days 1-7, off treatment for Days 8-28 (28-day cycles)
|
Drug: KRT-232
KRT-232, administered by mouth |
Experimental: Part B
Recommended KRT-232 dose and schedule from Part A
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Drug: KRT-232
KRT-232, administered by mouth |
Experimental: Part A Cohort 4b
KRT-232 240mg by mouth once daily for Days 1-5, off treatment for Days 6-28 (28-day cycles)
|
Drug: KRT-232
KRT-232, administered by mouth |
- To determine spleen response [ Time Frame: 24 weeks ]The proportion of patients achieving a ≥ 35% spleen volume reduction from Baseline to Week 24, as assessed by magnetic resonance imaging (MRI) or computed tomography (CT) scan
- To determine the change in modified MPN-SAF Total Symptom Score (TSS) at Week 24 and Week 48 [ Time Frame: 48 weeks ]Proportion of patients who have at least a 50% reduction from Baseline to Week 24 and Week 48 in the total symptom score as measured by the modified MPN-SAF v2.0
- RBC transfusion independence at Week 24 [ Time Frame: 24 weeks ]Proportion of patients who have RBC transfusion independence at week 24
- Complete remission and partial remission defined according to International Working Group-Myeloproliferative Neoplasms Research and Treatment and modified European LeukemiaNet criteria [ Time Frame: 24 weeks ]Proportion of patients who have complete remission and partial remission at week 24

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Confirmed diagnosis of PMF, post-PV MF or post-ET MF (WHO)
- High, intermediate-2, or intermediate-1 risk Dynamic International Prognostic System (DIPSS)
- Failure of prior treatment with JAK inhibitor (Part A) or ruxolitinib (Part B)
- ECOG ≤ 2
Exclusion Criteria:
- Prior splenectomy
- Splenic irradiation within 3 months prior to the first dose of KRT-232
- Active or chronic bleeding within 4 weeks prior to the first dose of KRT-232
- Prior MDM2 inhibitor therapy or p53-directed therapy
- Prior treatment with HDAC or BCL-2 inhibitors
- Grade 2 or higher QTc prolongation (> 480 milliseconds per NCI-CTCAE criteria, version 5.0)

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03662126
Contact: John Mei | 650-542-0136 | jmei@kartosthera.com |

Responsible Party: | Kartos Therapeutics, Inc. |
ClinicalTrials.gov Identifier: | NCT03662126 |
Other Study ID Numbers: |
KRT-232-101 |
First Posted: | September 7, 2018 Key Record Dates |
Last Update Posted: | November 26, 2019 |
Last Verified: | November 2019 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Product Manufactured in and Exported from the U.S.: | Yes |
Polycythemia Vera Primary Myelofibrosis Polycythemia Thrombocytosis Thrombocythemia, Essential Myeloproliferative Disorders Bone Marrow Diseases Hematologic Diseases |
Bone Marrow Neoplasms Hematologic Neoplasms Neoplasms by Site Neoplasms Blood Platelet Disorders Blood Coagulation Disorders Hemorrhagic Disorders |