• Documented informed consent of the participant and/or legally authorized representative

• Agreement to allow the use of archival tissue from diagnostic tumor biopsies. If unavailable, exceptions may be granted with study principal investigator (PI) approval

• Age: ≥ 18 years

• Eastern Cooperative Oncology Group (ECOG) ≤ 2 or Karnofsky performance status (KPS) ≥ 70

• Patients who are scheduled to receive or have already undergone allogeneic hematopoietic cell transplantation (alloHCT) from any donor type, any conditioning regimen, and regardless of GVHD prophylaxis will be include

• Patients must have AML, MDS, or CMML with mIDH1 diagnosis at diagnosis (regardless of time from HCT). Note: Patient with pre-HCT disease relapse will no be included if mIDH1 is not detected after relapse

• Day 30 marrow post alloHCT should show evidence of morphologic remission with \< 5% bone marrow (BM) blasts. Patients with MRD-positive status either by flow cytometry or IDH1 mutation testing will be eligible

• Patients with previous therapy with IDH1 inhibitors will be included

• Absolute neutrophil count (ANC) \> 1000/mm\^3 (within 28 days prior to day 1 of protocol)

• Hemoglobin ≥ 8.0 gm/dL (within 28 days prior to day 1 of protocol)

• Platelets ≥ 50,000/mm\^3 (within 28 days prior to day 1 of protocol) Note: Patients with lower counts can enroll if infection cytomegalovirus (CMV)/human herpes virus 6 (HHV6), etc. is being treated actively

• Bilirubin ≤ 2 x upper limit of normal (ULN) (within 28 days prior to day 1 of protocol) (unless has Gilbert's disease). Patients with abnormal liver function tests (LFTs) due to active GVHD will not be eligible

• Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase \[SGPT\]) ≤ 2 x ULN (within 28 days prior to day 1 of protocol). Patients with abnormal LFTs due to active GVHD will not be eligible

• Creatinine clearance of ≥ 30/min/1.73 m\^2 for participants with creatinine levels above institutional normal per 24 hour urine test or the Cockcroft-Gault formula (within 28 days prior to day 1 of protocol)

• Corrected QT interval (QTc) ≤ 480 ms (Note: To be performed within 28 days prior to day 1 of protocol therapy)

• Seronegative for HIV antigen/antibody (Ag/Ab) combo, hepatitis C virus (HCV) (if positive, hepatitis C ribonucleic acid \[RNA\] quantitation must be performed), active hepatitis B virus (HBV) (surface antigen negative), and syphilis (rapid plasma reagin \[RPR\]) (within 28 days prior to day 1 of protocol)

• Women of childbearing potential (WOCBP): negative urine or serum pregnancy test (within 28 days prior to day 1 of protocol). If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required

• Agreement by females and males of childbearing potential, defined as not being surgically sterilized (men and women) or have not been free from menses for \> 1 year (women only), to use an effective method of birth control or abstain from heterosexual activity for the course of the study through at least 3 months after the last dose of protocol therapy