A Study of JNJ-75276617 in Combination With Conventional Chemotherapy for Pediatric and Young Adult Participants With Relapsed/Refractory Acute Leukemias

A Phase I/Ib Study of JNJ-75276617 in Combination With Conventional Chemotherapy for Pediatric and Young Adult Participants With Relapsed/Refractory Acute Leukemias Harboring KMT2A, NPM1, or Nucleoporin Gene Alterations

The purpose of this study is to determine the recommended Phase 2 dose(s) (RP2Ds) of JNJ-75276617 in combination with a conventional chemotherapy backbone in pediatric and young adult participants with relapsed/refractory acute leukemia harboring histone-lysine N-methyltransferase 2A1 ([KMT2A1], nucleophosmin 1 gene (NPM1), or nucleoporin alterations in Part 1 (Dose Escalation) and to further evaluate safety at the RP2D(s) of JNJ-75276617 in combination with chemotherapy in pediatric and young adult participants with relapsed/refractory acute leukemia harboring KMT2A1, NPM1, or nucleoporin alterations and safety at the RP2D(s) of JNJ-75276617 as monotherapy in a select low burden of disease cohort in Part 2 (Dose Expansion).

Inclusion Criteria:

• Acute leukemia harboring histone-lysine N-methyltransferase 2A (KMT2A) or nucleophosmin 1 gene (NPM1) or nucleoporin (NUP98 or NUP214) alterations
• Performance status greater than or equal to (>=) 50 by lansky scale (for participants less than [<] 16 years of age) or >=50 percent (%) karnofsky scale (for participants >=16 years of age)
• Estimated or measured glomerular filtration rate >= 60 milliliter per minute per 1.73 meter square (mL/min/1.73m^2) based on the bed side schwartz formula

Exclusion Criteria:

• Received an allogeneic hematopoietic transplant within 60 days of screening
• Active acute graft-versus-host disease of any grade or chronic graft-versus-host which is not well-controlled
• Received immunosuppressive therapy post hematopoietic transplant within 30 days of enrollment
• Diagnosis of Down syndrome associated leukemia, acute promyelocytic leukemia, juvenile myelomonocytic leukemia
• Diagnosis of fanconi anemia, kostmann syndrome, shwachman diamond syndrome, or any other known bone marrow failure syndrome
• Prior exposure to menin-KMT2A inhibitors
• Prior cancer immunotherapy (ie [that is], Chimeric Antigen Receptor-T Cell Therapy [CAR-T], inotuzumab, gemtuzumab ozogamicin) 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)