FDA grants orphan drug status to potential treatment for ALL

The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to the experimental therapy enzomenib (DSP-5336) as a potential treatment for acute lymphoblastic leukemia (ALL), a form of blood cancer.

The FDA gives this designation to investigational medicines being developed to treat rare diseases, defined as conditions affecting fewer than 200,000 people in the U.S. Orphan drug designation is intended to encourage the development of treatments for rare diseases by providing financial and regulatory incentives to drug developers.

The designation gives enzomenib’s developer Sumitomo Pharma access to incentives including tax breaks, fee waivers, and the potential for seven years of market exclusivity if the therapy is ultimately approved.

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Orphan drug status could support enzomenib development

“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,” Tsutomu Nakagawa, president and CEO of Sumitomo Pharma America, said in a company press release.

ALL is a rare, aggressive form of blood cancer that develops due to the uncontrolled production of immune cells in the bone marrow. Enzomenib is designed to inhibit cancer cell growth by blocking the interaction between two proteins called menin and lysine (K)-specific methyltransferase 2A (KMT2A). This interaction plays a key role in the growth of acute leukemia and other tumor cells. Preclinical tests showed that enzomenib selectively inhibited growth in human acute leukemia cell lines with KMT2A rearrangements 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,” Nakagawa noted.

The FDA has previously granted enzomenib orphan drug designation as a potential treatment for acute myeloid leukemia (AML), another form of blood cancer.

Sumitomo Pharma America is currently sponsoring a Phase 1/2 clinical trial (NCT04988555) that’s testing enzomenib in adults with ALL, acute myeloid leukemia (AML), or certain other types of blood cancer. Some patients ages 12 and older with acute leukemia who weigh at least 40 kg (88 pounds) may also enroll at participating sites where permitted in the part of the study testing enzomenib on its own. Participants will be treated with enzomenib, on its own or in combination with other therapies. Goals of the study include evaluating the safety profile of the experimental therapy, identifying the optimal dosage for further testing, and assessing how many patients respond to treatment.

The Phase 1/2 study is currently recruiting participants at dozens of sites across North America, Europe, and Asia.