Oncaspar is a brand name for pegaspargase, a chemotherapeutic agent used primarily in the treatment of acute lymphoblastic leukemia (ALL), a type of cancer that affects the white blood cells. It is a modified enzyme designed to break down the amino acid asparagine, which is essential for the growth and survival of leukemia cells. By depleting asparagine, Oncaspar starves the leukemia cells, inhibiting their ability to proliferate. This medication is often used as part of a combination chemotherapy regimen, tailored to the specific needs of the patient. Oncaspar's formulation allows for less frequent dosing compared to other forms of asparaginase, potentially reducing the treatment burden on patients.