Aspacytarabine (BST-236), a possibly less toxic form of chemotherapy being developed by Biosight for people with acute myeloid leukemia (AML), has been designated an orphan medicinal product by the European Medicines Agency (EMA).
This follows the orphan drug designation granted to aspacytarabine by the U.S. Food and Drug Administration for the treatment of AML in June 2019.
Both designations are expected to support and expedite the clinical development and regulatory review of aspacytarabine, by providing benefits that include protocol design assistance, reduced regulatory fees, and market exclusivity of seven years in the U.S. and 10 years in the European Union if approved.
The FDA also granted aspacytarabine fast track status for patients ages 75 and older, and for those unfit to receive intensive chemotherapy as an initial treatment.
“Obtaining orphan medicinal product designation from the EMA is an additional, important recognition of aspacytarabine’s potential to provide a significant benefit to AML patients, including to older adults who are unfit for standard chemotherapy, by addressing the major need for effective and well tolerated treatment options,” Ruth Ben Yakar, PhD, CEO of Biosight, said in a press release.
Standard therapy for AML includes an intensive course of chemotherapy — usually with the agent cytarabine — to induce remission, followed by a consolidation regimen, using the same agent, to destroy any remaining leukemia cells. Treatment goal is to reduce the risk of a relapse.
However, cytarabine, a potent bone marrow suppressant, is linked with severe side effects that include brain toxicity, the inability to produce blood cells, and infections.
As such, it not considered an optimal choice for older patients and those with associated diseases.
Aspacytarabine is a new form of cytarabine, in which the chemotherapy agent is bound to the amino acid asparagine, acting as a new pro-drug of cytarabine. This means that cytarabine is gradually released after infusion, avoiding the cytarabine peak exposure that causes most of its side effects.
Aspacytarabine was investigated in a dose-escalation Phase 1/2 trial (NCT02544438), both as an initial treatment and after prior therapies, in AML patients who were unfit for standard induction therapy.
The therapy is also being investigated in the ELPIS Phase 2b trial (NCT03435848) as a potential treatment for newly diagnosed AML patients not eligible for standard induction regimens, either due to older age (75 years or higher) or to the presence of additional heart or lung diseases.
Previous results, which included data from 21 newly diagnosed AML patients who received aspacytarabine as part of the Phase 1/2 trial or the ELPIS trial, showed that aspacytarabine was safe and well tolerated in these patients, leading to prolonged survival.
A complete response to treatment was observed in 36% of these people, some of whom had undergone multiple courses of hypomethylating agents (HMA).
“We are encouraged by our progress, recently presenting updated data … that demonstrate efficacy across key measures including encouraging complete remission … duration of response and overall survival,” Yakar said.
These data “leave us well positioned to continue our rapid development of aspacytarabine, which we are expanding to additional Phase 2 trials, including in relapsed/refractory myelodysplastic syndrome and AML,” she added.