Aspacytarabine (BST-236 ) is a novel proprietary anti-metabolite. It is composed of cytarabine covalently bound to asparagine, acting as a pro-drug of cytarabine, enabling delivery of high cytarabine doses to leukemia patients with lower systemic exposure to the free drug.
Aspacytarabine is inactive in its intact prodrug form until cytarabine is gradually released at pharmacokinetics which decrease the systemic exposure to peak toxic cytarabine levels, resulting in reduced systemic toxicity and relative sparing of normal tissues, enabling therapy with high cytarabine doses to patients otherwise unfit to receive it.
Results from an ongoing Phase 2b study, presented by Dr. Jessica K. Altman at the 62nd Annual American Society of Hematology meeting demonstrate that aspacytarabine treatment of AML patients is safe and well tolerated, enabling delivery of high doses of cytarabine to older and unfit patients, leading to durable responses and prolonged survival.
A multi-center Phase 2b trial in the US and Israel in newly-diagnosed AML patients who are unfit for standard chemotherapy was recently completed, demonstrating safety and a strong single agent activitiy.
Additional Phase 2b clinical studies for evaluating the safety and efficacy of aspacytarabine as a second-line therapy of AML and MDS patients are ongoing in the US and in Europe.