BioSight Announces Phase I/II Results of its Cytarabine Pro-Drug BST-236 for Treatment of Acute Leukemia

AIRPORT CITY, Israel, December 14, 2017 /PRNewswire/ --

BioSight Ltd, a pharmaceutical development company, focused on the development of targeted oncology drugs, reports positive final results in a Phase I/II multi-center, open label, dose-escalating study of its lead product BST-236, a novel cytarabine pro-drug, as a single agent for induction therapy in acute leukemia patients. The results, presented at the 59^th Annual American Society of Hematology Meeting and Exposition by Dr. Tsila Zuckerman of the Rambam Healthcare Center, demonstrated safety and efficacy of BST-236 as a single agent in treatment of newly-diagnosed acute leukemia patients, unfit for standard induction therapy.

The study enrolled 26 acute leukemia patients, including 10 relapsed/refractory acute myelocytic leukemia (AML) patients and 16 newly-diagnosed older patients unfit for standard induction therapy (median age 78, range 70-90). Of the newly-diagnosed patients, 3 were diagnosed with de novo AML, 8 with AML secondary to myelodysplastic syndrome (MDS), the majority of them progressed to AML while under hypomethylating agent treatment, 3 with AML secondary to myeloproliferative neoplasms, and 2 were newly-diagnosed with acute lymphoblastic leukemia (ALL).

BST-236 was safe and well tolerated at all doses. The maximal dose explored was 6 g/m²/d, the molar equivalent of 4.1 g/m²/d of cytarabine. BST-236 was administrated as a 1-hour infusion for 6 consecutive days. Adverse events included mainly "on-target" hematological events and related infections. No cerebellar toxicity, no mucositis, no renal failure, and no alopecia events were reported.

Forty-five percent of the newly diagnosed AML patients (de novo and secondary to MDS) responded to BST-236, and 36% reached a durable complete remission (CR) after 1 or 2 induction courses. The median age of the responding patients was 80 years, 60% of them had secondary AML, 40% of responders were azacitidine resistant, and 60% and 40% had adverse or intermediate ELN score, respectively. In addition, 1 of the 2 ALL patients, a 90-year old man, reached a durable CR.

All CRs were durable, accompanied by survival of 6.5 to currently 20 months (median not reached). The median overall survival of the entire subgroup of newly-diagnosed AML (responders and non-responders) was 6.5 months, with a 27% 1-year survival rate.

Based on these encouraging results, BioSight intends to launch a multi-center Phase IIb study in the US and Israel in the coming months. The study will enroll 65 newly-diagnosed AML patients, age ≥75 or with comorbidities, who are unfit for standard induction therapy.

Dr. Ruth Ben Yakar, BioSight's CEO said: "We are very excited with the results achieved in the BST-236 Phase I/II study. We are especially encouraged by the good safety and efficacy of BST-236 in older and unfit patients with poor baseline characteristics and prognosis. BST-236 activity was demonstrated to be targeted, enabling safe delivery of high cytarabine doses to older patients, up to 90 years old, achieving approximately 3-fold higher response rates compared to currently available treatments. Importantly, the remissions were durable, correlating with significantly prolonged survival. We intend to launch a multi-center Phase IIb study in the coming months to confirm these encouraging results".

About BST-236 

BST-236, a novel proprietary compound under development for the treatment of hematological malignancies, is composed of cytarabine covalently bound to asparagine. BST-236 acts as a cytarabine pro-drug, releasing cytarabine inside target cells with reduced non-specific systemic toxicity, thus enabling delivery of high cytarabine doses to leukemia cells with relative sparing of normal tissues.

About BioSight Ltd. 

BioSight is a private Israeli clinical-stage pharmaceutical development company, founded by Dr. Stela Gengrinovitch and headed by Dr. Ruth Ben Yakar. BioSight focuses on the development of novel caner-targeted pro-drugs.

Contact: Dr. Ruth Ben Yakar, CEO, [email protected]

SOURCE BioSight, Ltd