Biosight Presents Updated Clinical Data from Ongoing Phase 2b Study of Aspacytarabine (BST-236) in an Oral Presentation at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting

Complete remission rate of 39%, of which 63% were minimal residual disease negative, achieved in expanded data set in frontline acute myeloid leukemia

Durable responses with median overall survival in responders not reached at 24 months

Efficacy and safety results achieved in the most challenging AML patient populations including those unfit to receive intensive chemotherapy

AIRPORT CITY, Israel, June 04, 2021 (GLOBE NEWSWIRE) -- Biosight Ltd., a pharmaceutical development company developing innovative therapeutics for hematological malignancies and disorders, today presents updated clinical data from the Company’s ongoing Phase 2b clinical trial evaluating single-agent aspacytarabine (BST-236) as a first-line acute myeloid leukemia (AML) therapy for patients unfit for standard induction chemotherapy in an oral presentation at the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting which will be held virtually from June 4-8, 2021.

“This expanded data set is highly encouraging, building upon the strong foundation of clinical data across Phase 1 and 2 studies that suggest aspacytarabine may serve as a potential standard-of-care treatment option for AML patients,” said Jessica Altman M.D., Professor, Medicine, Hematology Oncology Division, Feinberg School of Medicine, Robert H. Lurie Comprehensive Cancer Center of Northwestern University and Lead Study Investigator. “The complete remission rate is 39%, in a patient population with challenging baseline characteristics, including patients with secondary AML, prior treatment with hypomethylating agents, older age, and adverse European LeukemiaNet risk scores. These encouraging efficacy data as a monotherapy, combined with a favorable safety profile in AML patients unfit for intensive chemotherapy, with all responders achieving complete hematological recovery, underscores my belief that aspacytarabine could expand the reach of intensive chemotherapy to a broader range of AML patients.”

Key highlights from the oral presentation titled, “Efficacy and safety of aspacytarabine (BST-236) as a single-agent, first-line therapy for patients with acute myeloid leukemia unfit for standard chemotherapy” presented by Dr. Altman include:

• As of the data cutoff date of April 8, 2021, 46 AML patients from the Phase 2b study were evaluable for safety and efficacy analysis, building upon the 31 patients previously reported for response analysis
• Baseline patient characteristics include a median age of 75 years, 41% of patients (n=19) with ECOG PS 2, 37% of patients (n=17) with secondary AML, 13% with prior hypomethylating agents (HMAs) ± venetoclax treatment (n=6) and 39% (n=18) with adverse European LeukemiaNet (ELN) scores
• Repeated 6-day courses of 4.5 g/m²/d aspacytarabine were well-tolerated in older and unfit patients
• Complete remission (CR) rates were 39% across all evaluable patients (n=46), 45% excluding patients with prior HMA ± venetoclax therapy (n=40), 52% in de novo AML patients (n=29), 18% in secondary AML patients (n=17), 40% in patients ≥ 75 years old (n=25), and 33% in patients with adverse ELN risk scores
• Rapid complete hematological recovery was observed in all patients who achieved a complete bone marrow response, within a median time of 28 days (range 17-39) for complete neutrophil recovery following induction and 15 days (range 11-31) following consolidation, and within a median time for complete platelet recovery of 26 days (range 20-37) and 23 days (range 22-31) following induction and consolidation, respectively
• 63% of evaluable CRs were minimal residual disease negative (MRD(-))
• Follow-up is ongoing; median duration of response (DOR) was not reached (NR) at the end of patient follow-up at 12 months
• Median overall survival (OS) for all patients is presently 10 months (95% CI, 6- NR); NR at 24 months for both de novo AML patients and patients in CR; and 6.8 months (95% CI, 2.7-NR) in secondary AML patients

Dr. Ruth Ben Yakar, Chief Executive Officer of Biosight, said, “We are thrilled by the encouraging results of this larger data set which strengthen our conviction in the potential of aspacytarabine to provide a more effective and less toxic chemotherapy approach in the treatment of AML patients. These results bolster our momentum with our aspacytarabine clinical trial program, with the completion of enrollment into our Phase 2b study recently announced, and with the planned expansion into additional Phase 2 studies in patients with relapsed/refractory myelodysplastic syndrome (MDS) or AML.”  

About Aspacytarabine (BST-236)

Aspacytarabine is a novel proprietary anti-metabolite. It is composed of cytarabine covalently bound to asparagine, acting as a prodrug of cytarabine. Cytarabine has served as the backbone of AML therapy for over 45 years due to its superior efficacy; however, it is associated with severe bone marrow, gastrointestinal, and neurological toxicities, which significantly limit its use, especially in older and medically compromised patients. Due to its unique pharmacokinetics and metabolism, aspacytarabine enables high-dose therapy with lower systemic exposure to free cytarabine and relative sparing of normal tissues. As such, aspacytarabine may serve as a superior therapy for AML and other hematological malignancies and disorders, including for older adults who are unfit to receive intensive therapy.

Aspacytarabine was granted FDA Fast Track Designation for the first-line treatment of AML patients unfit for standard chemotherapy, and Orphan Drug Designations by the FDA and EMA, which entitle Biosight to 7 and 10 years of market exclusivity in the US and Europe, respectively, upon marketing approval of aspacytarabine for the treatment of AML in each territory.

Interim results from an ongoing Phase 2b study evaluating single-agent aspacytarabine as a first-line AML therapy have demonstrated safety and single-agent activity, and additional studies are being launched to evaluate aspacytarabine as a second-line treatment for patients with relapsed or refractory MDS or AML. For more information regarding the Phase 2b clinical study of BST-236, please visit www.clinicaltrials.gov.

About Biosight Ltd.

Biosight is a private Phase 2 clinical stage biotech company developing innovative therapeutics for hematological malignancies and disorders. Biosight’s lead product, aspacytarabine (BST-236), is an innovative proprietary anti-metabolite which addresses unmet medical needs by enabling high-dose chemotherapy with reduced systemic toxicity. Aspacytarabine is currently being investigated as a single agent in a Phase 2b clinical trial for the first-line treatment of AML, following completion of a Phase 1/2a study which demonstrated tolerability with promising efficacy in the challenging population of AML patients unfit for intensive standard-of-care chemotherapy. Additional Phase 2 studies to be initiated in 2021 include a study in patients with relapsed/refractory AML and MDS, including a study in collaboration with the European cooperative group, Groupe Francophone des Myélodysplasies (GFM). For additional information, please visit www.biosight-pharma.com.

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Chuck Padala
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