A Phase 1/2 Study of Bleximenib in Participants With Acute Leukemia

Eligibility Criteria

• * Relapsed or refractory (R/R) acute leukemia and has exhausted, or is ineligible for, available therapeutic options
• * Participants greater than or equal (\>=)12 and less than (\<) 18 years of age with a body weight of \>= 40 kg are only eligible for the Phase 1 adolescent cohort
• * Acute leukemia harboring histone-lysine N-methyltransferase 2A (KMT2A), nucleophosmin 1 gene (NPM1) or nucleoporin 98 gene or nucleoporin 214 gene (NUP98 or NUP214) alterations
• * Participants greater than 18 years are eligible
• * Must have had an initial diagnosis of acute myeloid leukemia (AML) per the WHO 2022 classification criteria.
• * AML harboring KMT2A-r (gene rearrangement/translocation) or NPM1 mutations only
• * Pretreatment clinical laboratory values meeting the following criteria: (a) Hematology: white blood cell (WBC) count less than or equal to (\<=) 20\*10\^9/liter (L) and renal function; Estimated or measured glomerular filtration rate greater than or equal to (\>=) 50 milliliter per minute (mL/min) per four variable modified diet in renal disease (MDRD) equation
• * Eastern Cooperative Oncology Group (ECOG) performance status grade of 0, 1 or 2. Adolescent participants only: Performance status \>=70 by Lansky scale (for participants less than \[\<\]16 years of age) or \>=70 Karnofsky scale (for participants \>=16 years of age)
• * A participant of childbearing potential must have a negative highly sensitive serum beta-human chorionic gonadotropin at screening and within 48 hours prior to the first dose of study treatment
• * A participant must agree to all the following during the study and for 90 days after the last dose of study treatment: (a) wear a condom when engaging in any activity that allows for passage of ejaculate to another person; (b) not to donate sperm or freeze for future use for the purpose of reproduction. In addition, the participant should be advised of the benefit for a partner to use a highly effective method of contraception as condom may break or leak
• * Acute promyelocytic leukemia, diagnosis of Down syndrome associated leukemia or juvenile myelomonocytic leukemia according to World Health Organization (WHO) 2016 criteria
• * Active central nervous system (CNS) disease
• * Prior solid organ transplantation
• * QTc according to Fridericia's formula (QTcF) for males \>= 450 millisecond (msec) or for females \>= 470 msec. Participants with a family history of Long QT syndrome are excluded
• * Exclusion criteria related to stem cell transplant: a. Received prior treatment with allogenic bone marrow or stem cell transplant \<=3 months before the first dose of study treatment; b. Has evidence of graft versus host disease; c. Received donor lymphocyte infusion \<=1 month before the first dose of study treatment; d. Requires immunosuppressant therapy (exception: daily doses \<=10 milligrams (mg) prednisone or equivalent are allowed for adrenal replacement)
• * Prior cancer immunotherapy within 4 weeks prior to enrollment or blinatumomab within 2 weeks prior to enrollment. Additional prior cancer therapies must not be given within 4 weeks prior to enrollment or 5 half-lives of the agent (whichever is shorter)