ONCASPAR is the only FDA-approved pegylated formulation of L-asparaginase, the enzyme that depletes the amino acid asparagine. For the last 25 years, L-asparaginase has been an important component in the treatment of acute lymphoblastic leukemia (ALL).¹

While normal cells can produce asparagine, leukemic cells are unable to produce enough asparagine to survive on their own.  L-asparaginase is given to ALL patients to ensure depletion  of asparagine that is circulating in the blood.² Depletion (starving the leukemic cells) of asparagine ultimately results in leukemic cell death.³

ONCASPAR allows patients to gain the full benefits of asparaginase therapy with enhanced patient convenience over native L-asparaginase (nonpegylated form). Through the process of pegylation, the half-life of L-asparaginase is significantly increased ^1,2,4  and the L-asparaginase activity is sustained.^1,4-7

ONCASPAR can be administered through intramuscular (IM) injection or intravenous (IV) infusion. When utilized as a component of induction therapy for ALL, 1 dose of Oncaspar achieved similar levels of asparagine depletion as 9 doses of native L-asparaginase.^3,5,* 
 
The use of ONCASPAR for the treatment of ALL continues to be explored to evaluate the optimal duration of use.

ONCASPAR is indicated as a component of a multiagent chemotherapeutic regimen for the first –line treatment of patients with acute lymphoblastic leukemia (ALL) and for the treatment of patients with acute lymphoblastic leukemia and hypersensitivity to native forms of L-aspariginase. ³

ONCASPAR is contraindicated in patients with a history of serious allergic reactions to ONCASPAR, and in patients with a history of serious thrombosis, pancreatitis, or serious hemorrhagic events with prior L-asparaginase therapy.

ONCASPAR should be discontinued in the case of anaphylaxis or serious allergic reactions, thrombosis, or pancreatitis. Glucose intolerance, in some cases irreversible, can occur. Coagulopathy can occur. Perform appropriate monitoring.

The most common adverse reactions with ONCASPAR (>2%) are allergic reactions (including anaphylaxis), hyperglycemia, pancreatitis, central nervous system (CNS) thrombosis, coagulopathy, hyperbilirubinemia, and elevated transaminases.

In study 2 (n= 2770), the per-patient incidence for Grades 3 and 4 nonhematologic toxicities were: elevated transaminases (11%), coagulopathy (7%), hyperglycemia (5%), CNS thrombosis/hemorrhage (2%), pancreatitis (2%), clinical allergic reaction (1%), and hyperbilirubinemia (1%). There were 3 deaths due to pancreatitis.

Enzon Pharmaceuticals, Inc.制药公司于11月10日宣布，FDA已经批准其儿科抗白血病药Oncaspar的标签变更。新标签允许Oncaspar通过静脉注射给药，这减少了儿科白血病患者注射Oncaspar的次数。此前，该药只能通过肌注给药，患者在接受肌注时常有疼痛感。
　　
Oncaspar为L-天门冬酰胺酶的修型，是由单氧基聚乙二醇（PEG）的共价结合单位而产生的一种酶。L-天门冬酰胺酶可使天冬酰胺耗尽，而天冬酰胺正是某些特定白血病细胞赖以生存的物质。
　　
Oncaspar于1994年获得FDA的批准用于治疗急性淋巴性白血病，但原来的产品会引起超敏反应。Enzon公司采用独家技术对这种产品进行改进之后，新型Oncaspar除了可以降低免疫原性之外，使用起来也更为方便（与原来每周用药两次的旧产品相比，新药每两周仅用药一次），更贴近患者的需求。
　　
2005年，美国的白血病新增患者约有3.5万名。其中急性淋巴性白血病患者人数约为4000人。尽管大部分为儿科患者，但1/3的新增病例为成人患者。

Pegaspargase （ Oncaspar ） ：治疗急性淋巴细胞白血病的成年人和儿童。 2006年7月批准。