Sponsor Decision to Terminate Trial

The main aim of the study is to see if signs and symptoms of myelodysplastic syndromes disappear when treated with pevonedistat combined with decitabine and cedazuridine.

Participants will receive an infusion of pevonedistat 3 times during a 28-day cycle. They will also take decitabine and cedazuridine tablets once a day for the first 5 days of the same cycle. A minimum of 6 28-day cycles is recommended, but participants can stop treatment at any time.

A bone marrow biopsy, bone marrow aspirates, and blood samples will be collected during the study.

Participants will attend a follow-up visit 30 days after their last dose of pevonedistat. Once treatment has ended, participants will be followed up with either monthly clinic visits or will be contacted every 3 months.

The drug being tested in this study is called Pevonedistat (TAK-924/MLN4924). Pevonedistat is being tested to treat people who have higher-risk myelodysplastic syndromes (HR MDS). This study will look at the overall survival, event free survival and response in people who take pevonedistat in combination with oral decitabine and cedazuridine in addition to standard care.

The study will enroll approximately 94 patients. Participants will be assigned to following treatment group:

• Pevonedistat 20 mg/m^2 + Decitabine 35 mg + Cedazuridine 100 mg

All participants will receive pevonedistat in combination with decitabine and cedazuridine as specified in the protocol.

This multi-center trial will be conducted in the United States. The overall time to participate in this study is approximately 30 months. Participants will make multiple visits to the clinic and will be contacted by telephone OR plus a final visit after receiving their last dose of drug/compound 30 days after last dose of study drug for event free survival (EFS) follow-up followed by overall survival (OS) follow-up.

Inclusion Criteria:

1. Documented morphologically confirmed diagnosis of HR MDS according to the 2016 World Health Organisation (WHO) classification.

2. All participants must also have one of the following Prognostic Risk Categories based on the Revised International Prognostic Staging System (IPSS-R): Very high >6 points, high (4.5 to 6 points), or intermediate >3 to 4.5 points. Participants in the intermediate category must have >5% bone marrow myeloblasts.

3. Have an Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) of ≤2.

4. Able to undergo the study-required bone marrow sample collection procedures.

5. Suitable venous access for the study-required blood sampling (i.e., including pharmacokinetic (PK) sampling).

6. Known Human Immunodeficiency Virus (HIV)-positive participants who meet the following criteria will be considered eligible:

   • Cluster of differentiation 4 (CD4) count >350 cells per cubic millimeter (cells/mm^3).
   • Undetectable viral load.
   • Maintained on modern therapeutic regimens.
   • No history of Acquired Immune Deficiency Syndrome (AIDS)-defining opportunistic infections.

Exclusion Criteria:

1. Histologically or cytologically documented diagnosis of Acute Myelogenous Leukemia (AML) or Chronic Myelomonocytic Leukemia (CMML).
2. Previous treatment for HR MDS with chemotherapy or other antineoplastic agents, including hypomethylating agents (HMAs), such as decitabine or azacitidine. Previous treatment is permitted with hydroxyurea and with lenalidomide, except that lenalidomide may not be given within 8 weeks before the first dose of study drug(s).
3. Have known hypersensitivity to pevonedistat or its excipients.
4. Have known hypersensitivity to oral decitabine and cedazuridine or its excipients.
5. Diagnosed or treated for another malignancy within 2 years before enrollment or previously diagnosed with another malignancy and have any evidence of residual disease. Participants with nonmelanoma skin cancer or carcinoma in situ of any type are not excluded if they have undergone resection.
6. Participants with either clinical evidence of or history of central nervous system (CNS) involvement.
7. Are known hepatitis B surface antigen seropositive, or known or suspected active hepatitis C infection. (Note: Participants who have isolated positive hepatitis B core antibody [i.e., in the setting of negative hepatitis B surface antigen and negative hepatitis B surface antibody] must have an undetectable hepatitis B viral load. Participants with history of hepatitis C virus [HCV] infection must have been treated and cured. For participants with HCV infection who are currently on treatment, they are eligible if they have an undetectable HCV viral load.)
8. Have known hepatic cirrhosis or severe pre-existing hepatic impairment.
9. Have known cardiopulmonary disease, defined as unstable angina, clinically significant arrhythmia, congestive heart failure (New York Heart Association Class III or IV), and/or myocardial infarction within 6 months before first dose, or severe pulmonary hypertension. As an example, well-controlled atrial fibrillation (AF) would not be an exclusion, whereas uncontrolled AF would be an exclusion.
10. Have positive test result for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that is laboratory confirmed by a reverse transcription polymerase chain reaction (RT-PCR) test at screening. Testing related to coronavirus disease 2019 (COVID-19) must be performed according to institutional policy and/or per local regulatory guidelines.
11. Participants who have had a known infection of SARS-CoV-2 or COVID-19 are permitted if COVID-19 RT-PCR test is negative prior to the screening visit and they present with no symptoms. Participants with documented vaccination history for COVID-19 do not need to be tested, unless they are symptomatic, according to institutional policy and/or local regulatory guidelines.

Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

IPD from eligible studies will be shared with qualified researchers according to the criteria and process described on https://vivli.org/ourmember/takeda/. For approved requests, the researchers will be provided access to anonymized data (to respect patient privacy in line with applicable laws and regulations) and with information necessary to address the research objectives under the terms of a data sharing agreement.