In mid-August 2021, biotechnology and pharmaceutical development company Biosight Ltd. shared that it had begun a Phase 2 clinical trial regarding one of its proprietary treatments – and that the first patient had enrolled. Sponsored by the Groupe Francophone des Myélodysplasies (GFM), the study seeks to explore the safety, efficacy, and tolerability of BST-236 (aspacytarabine) for patients with relapsed or refractory (R/R) myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML). Unfortunately, these conditions, especially AML, may be difficult to treat or come with a poor prognosis for older individuals. Thus, if successful, BST-236 would have the potential to greatly improve patient outcomes.

BST-236

So what exactly is BST-236? According to Biosight, BST-236 is:

a novel proprietary anti-metabolite…composed of cytarabine covalently bound to asparagine…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.

Thus far, the treatment has already received Orphan Drug and Fast Track designations within the United States, as well as Orphan Drug designation within the European Union (EU).

Some data on BST-236 is already available, following other previous studies. If you are interested in learning more about BST-236, take a look at this data shared during the American Society of Hematology (ASH) Annual Meeting in 2018. You may also find the results of a Phase 1/2a study published in Blood Advances.

Myelodysplastic Syndromes (MDS)

Radiation, chemotherapy, and chemical exposure are all thought to be potential triggers for myelodysplastic syndromes (MDS), progressive conditions which prevent the bone marrow from producing healthy platelets, as well as healthy white and red blood cells. However, doctors are still not sure about the exact cause of MDS. Regardless, patients with MDS experience blood cells which fail to mature. Because of the range of illnesses and severities, it is difficult to identify how MDS may progress from patient to patient. MDS tends to affect males slightly more than females, as well as those of older age. Symptoms include:

• Anemia (low red blood cell count)
• Neutropenia (low white blood cell count)
• Thrombocytopenia (low platelet count)
• Fatigue
• Shortness of breath
• Frequent infections
• Chest pain
• General malaise
• Easy bruising and bleeding
• Heart palpitations
• Pale skin

Acute Myeloid Leukemia (AML)

In around half of all patients, MDS progresses to become acute myeloid leukemia (AML), a type of blood and bone marrow cancer. As abnormal blood cells develop, they crowd out healthy cells. Symptoms include:

• Pallor (pale skin)
• Frequent infections
• Easy bruising and bleeding
• Lethargy
• Fatigue
• Bone pain
• Shortness of breath and/or difficulty breathing
• Fever