The U.S. Food and Drug Administration (FDA) has granted orphan drug designation to Oryzon Genomics‘ iadademstat, an investigational oral therapy for people with acute myeloid leukemia (AML).

“Receiving Orphan Drug Designation for iadademstat in AML is an important recognition of the role that new drugs with new mechanisms of action may bring to this patient community, where we do not yet have any potentially curative medicines besides stem cell transplant,” Torsten Hoffmann, PhD, Oryzon’s global head of research and development and chief scientific officer, said in a press release.

Iadademstat is an inhibitor of LSD1, an enzyme that alters which genes are active in a cell by opening up tightly packed regions of DNA called chromatin. Genes found inside these regions cannot be turned into proteins, making them effectively “switched off.”

LSD1 contributes to AML by switching many of these genes back on. It also has been shown to destabilize the tumor suppressor FBXW7, removing one of the ways by which cells guard against cancer. Other studies have shown that blocking LSD1 can help myeloid cells mature in a healthy, non-cancerous manner.

The candidate therapy is currently undergoing Phase 2a testing (EudraCT number 2018-000482-36) in Spain. Data from the study, called ALICE, was presented at the virtual 62nd Congress of the American Society of Hematology late last year.

“Iadademstat is showing a high overall response rate of 85% in our ongoing clinical Phase 2 study ALICE, with a rapid onset of action and with durable responses,” Hoffmann said of the trial’s progress.

“In addition, we have seen a good safety and tolerability profile in the combination treatment with azacitidine,” Hoffmann said.

Of those responding to the therapy, 64% achieved complete remissions — or no signs of cancer — and 36% achieved partial remissions, with an average response time of 34 days. Furthermore, both the partial and complete responses lasted more than six months among 86% of the responding patients.

With the recent FDA decision, iadademstat now has orphan drug status for the treatment of AML in both the U.S. and the European Union. In both cases, the designation helps to speed development by providing benefits such as protocol design assistance, reduced regulatory fees, and a period of market exclusivity if approved. This exclusivity lasts seven years in the U.S. and 10 years in the EU.

“Future Phase 2 clinical trials in further combination treatments of AML are planned for the second half of this year,” Hoffmann said.