This study will enroll participants with myelodysplastic syndromes (MDS) with an Isocitrate dehydrogenase protein, 1 (IDH1) mutation, who have not received treatment with a hypomethylating agent previously. Participants will be randomized to receive either ivosidenib (IVO) alone or azacitidine (AZA) alone. IVO will be administered daily throughout the 28-day treatment cycle and AZA will be administered for the first 7 days of each 28-day cycle. Study visits will be conducted every week during Cycle 1 (Days 1, 8, 15, and 22), and Day 1 of each cycle thereafter. After the last dose of treatment, participants will attend an safety follow-up visit and participants will be followed to assess overall survival. Study visits may include a bone marrow aspirate, physical exam, echocardiogram (ECHO), electrocardiogram (ECG), blood and urine analysis, and questionnaires.

Inclusion Criteria:

• Diagnosis of HMA naive IDH1 R132 mutated MDS defined according to WHO criteria (5th edition):
• Moderate high, high and very high-risk MDS per IPSS-M score will be eligible regardless of blood counts and with blast counts 0-19%.
• Low and moderate low-risk MDS per IPSS-M score must:
• Have cytopenias related to MDS, defined as: <100 platelets/microliter, or absolute neutrophil count (ANC) <1000/mm3, or hemoglobin <10g/dL AND
• Have a blast count between 5-19% AND
• Be eligible for HMA therapy (very low risk participants are to be excluded)
• Locally or centrally confirmed IDH1 R132 C/G/H/L/S mutation

Exclusion Criteria:

• Received prior anticancer/disease modifying treatment for MDS (including HMA's, cytotoxic chemotherapy, investigational agents, bcl-2 inhibitor based-regimens, hematopoietic stem cell transplant (HSCT), IDH1 inhibitors). For LR-MDS patients, prior treatment with growth factors, luspatercept, lenalidomide, and imetelstat are allowed.
• >20% blasts by morphology or immunohistochemistry on screening bone marrow aspirate/biopsy

Qualified scientific and medical researchers can request access to anonymized patient-level and study-level clinical trial data. Access can be requested for all interventional clinical studies:

• used for Marketing Authorization (MA) of medicines and new indications approved after 1 January 2014 in the European Economic Area (EEA) or the United States (US).
• where Servier is the Marketing Authorization Holder (MAH). The date of the first MA of the new medicine (or the new indication) in one of the EEA Member States will be considered for this scope.

In addition, access can be requested for all interventional clinical studies in patients:

• sponsored by Servier
• with a first patient enrolled as of 1 January 2004 onwards
• for New Chemical Entity or New Biological Entity (new pharmaceutical form excluded) for which development has been terminated before any Marketing authorization (MA) approval.

After Marketing Authorization in EEA or US if the study is used for the approval.

Researchers should register on Servier Data Portal and fill in the research proposal form. This form in four parts should be fully documented. The Research Proposal Form will not be reviewed until all mandatory fields are completed.