On July 30, 2026 Sumitomo Pharma America, Inc. (SMPA) reported that the U.S. Food and Drug Administration (FDA) has granted orphan drug designation to enzomenib (DSP-5336) for the treatment of patients with acute lymphoblastic leukemia (ALL). Enzomenib is an investigational, oral, small molecule inhibitor of the menin and lysine (K)-specific methyltransferase 2A (KMT2A) protein interaction, a key interaction in acute leukemia and other tumor cell proliferation and growth.
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Orphan drug designation is granted by the FDA to a drug or biological product to prevent, diagnose, or treat a rare disease or condition.1 The FDA previously granted orphan drug designation to enzomenib for acute myeloid leukemia (AML) in June 2022. The safety and efficacy of enzomenib is currently being clinically evaluated in a Phase 1/2 dose-escalation/dose-expansion study in patients with relapsed or refractory acute leukemia (NCT04988555) and the registrational Phase 2 Horizen-1 R/R mono AML/ALL (KMT2Ar + NPM1m) study.
"The availability and selection of treatment choices is a major clinical and logistical challenge for patients with acute lymphoblastic leukemia, a challenge underscored by the complexity of sequencing therapies," said Tsutomu Nakagawa, President and CEO of Sumitomo Pharma America (SMPA). "Receiving Orphan Drug Designation for enzomenib for the treatment of ALL is an exciting development that reinforces the molecule’s potential. We will work closely with the FDA to advance clinical research of enzomenib in the hopes of bringing an innovative new treatment option to people living with ALL."
ALL, also known as acute lymphocytic leukemia, progresses quickly if untreated. It is characterized by an acute onset and occurs when the bone marrow produces an overabundance of lymphocytes. In ALL, impaired blood cell production can increase susceptibility to infections and may result in anemia and an increased risk of bleeding. ALL cells may spread to other bodily areas including the brain and spinal cord.2
About Enzomenib (DSP-5336)
Enzomenib is an investigational, oral, small molecule inhibitor of the menin and lysine (K)-specific methyltransferase 2A (KMT2A) protein interaction, a key interaction in acute leukemia and other tumor cell proliferation and growth. Menin is a scaffold nuclear protein that plays key roles in gene expression and protein interactions involved in many biological pathways, including cell growth, cell cycle, genomic stability, and hematopoiesis.3,4 In preclinical studies, enzomenib has shown selective growth inhibition in human acute leukemia cell lines with KMT2A rearrangements or NPM1 mutations.3,5 Enzomenib reduced the expression of the leukemia-associated genes HOXA9 and MEIS1 and increased the expression of the differentiation gene CD11b in human acute leukemia cell lines with KMT2A rearrangements or NPM1 mutation.6,7 The safety and efficacy of enzomenib is currently being clinically evaluated in a Phase 1/2 dose-escalation/dose-expansion study in patients with relapsed or refractory acute leukemia (NCT04988555) and the registrational Phase 2 Horizen-1 R/R mono AML/ALL (KMT2Ar + NPM1m) study. The FDA granted Orphan Drug Designation for enzomenib for the indication of acute myeloid leukemia in June 2022. The FDA granted Fast Track Designation for enzomenib for the indication of relapsed or refractory acute myeloid leukemia with KMT2Ar or NPM1m in June 2024. Japan’s Ministry of Health, Labour and Welfare (MHLW) granted Orphan Drug Designation for enzomenib for the indication of relapsed or refractory acute myeloid leukemia with KMT2Ar or NPM1m in September 2024.
(Press release, Sumitomo Dainippon Pharma, JUL 30, 2026, View Source [SID1234669556])