The following article features coverage from the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting. Click here to read more of Hematology Advisor‘s conference coverage.

Among patients with acute myeloid leukemia (AML) who cannot tolerate chemotherapy, first-line aspacytarabine appears to be both safe and effective, according to research presented at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting.

Aspacytarabine (also known as BST-236), a prodrug of cytarabine which is linked with attenuated systemic toxicity, may help patients with AML unfit for cytarabine to undergo systemic treatment. BST-236 is inactive until gradual release of cytarabine.

For this ongoing, single-arm, phase 2b study ( Identifier: NCT03435848), researchers evaluated the safety and efficacy of aspacytarabine among newly diagnosed patients with AML who were not considered fit for standard chemotherapy. Eligible patients included those with secondary AML and those who had previously undergone hypomethylating agent therapy.

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Since trial initiation, 46 evaluable patients have been enrolled and received 1 to 4 courses of aspacytarabine 4.5 g/m2/day. The median patient age was 75 years, 26 patients (53%) had de novo AML, 17 patients (37%) had secondary AML, and 6 patients (13%) had previously received hypomethylating agent therapy.

The 30-day mortality rate was 10.6%. Overall, among the 43 enrolled patients who were evaluable for treatment efficacy, the complete remission rate was 39%; all had complete hematologic recovery in a median of 28 days.

Of the patients who had a complete response who were evaluable for minimal residual disease, 63% were negative. Median duration of response and median overall survival were not reached at the time of this presentation among patients with a complete remission.

Grade 3 or worse adverse events occurring in at least 20% of patients included hematologic events and infections.

“The cumulative clinical data suggest that aspacytarabine, a time-limited single-agent treatment, is safe and efficacious as a first-line therapy for patients who are unfit for intensive chemotherapy, which may establish it as a new tolerable AML chemotherapy backbone,” the authors wrote.

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Read more of Hematology Advisor’s coverage of the 2021 ASCO Annual Meeting by visiting the conference page.


Altman JK, Koprivnikar J, McCloskey JK, et al. Efficacy and safety of aspacytarabine (BST-236) as a single-agent, first-line therapy for patients with acute myeloid leukemia unfit for standard chemotherapy. J Clin Oncol. 2021;39:(suppl 15; abstr 7007). doi:10.1200/JCO.2021.39.15_suppl.7007