Sumitomo Pharma's Enzomenib gets Orphan Drug Designation by US FDA

Investigational menin inhibitor receives second orphan status, with Phase 1/2 and registrational Phase 2 studies underway in acute leukemia

Sumitomo Pharma America, Inc. (SMPA) announced that the US 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 that targets the interaction between menin and lysine-specific methyltransferase 2A (KMT2A) proteins, a key pathway involved in the development and growth of acute leukemia and other cancers. 

The designation marks the second orphan drug status for enzomenib. In June 2022, the FDA granted orphan drug designation to the therapy for the treatment of acute myeloid leukemia (AML).

Orphan drug designation is granted by the FDA to therapies intended to prevent, diagnose or treat rare diseases and provides incentives to support the development of medicines for patients with unmet medical needs.

Enzomenib is currently being evaluated in a Phase 1/2 dose-escalation and dose-expansion study involving patients with relapsed or refractory acute leukemia. The therapy is also being studied in the registrational Phase 2 Horizen-1 trial, which is evaluating enzomenib monotherapy in patients with relapsed or refractory AML and ALL carrying KMT2A rearrangements (KMT2Ar) or NPM1 mutations.

"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.

"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," he added.

Acute lymphoblastic leukemia, also known as acute lymphocytic leukemia, is a rapidly progressing blood cancer in which the bone marrow produces excessive immature lymphocytes. If left untreated, the disease can impair normal blood cell production, increasing the risk of infections, anaemia and bleeding, and may spread to the brain and spinal cord.

Enzomenib remains an investigational therapy, and its safety and efficacy have not yet been established by regulatory authorities.