Pegylated L-asparaginase (specialist) Pregnancy: Can cause fetal harm based on published animal/literature data; no human data available. Advise pregnant women of the potential risk to a fetus.

Pegaspargase

Brand names: Oncaspar

Pegaspargase is a specialist parenteral enzyme used as a component of combination chemotherapy in the treatment of acute lymphoblastic leukaemia.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 2,000 International Units/m² (adult patients more than 21 years of age)

Route: Intramuscular or intravenous (IV diluted in 100 mL sodium chloride 0.9% or glucose 5%, infused over 1–2 hours into a running infusion)

Frequency: No more frequently than every 14 days

Product: ONCASPAR (US labelling; no UK SPC captured). Patients up to and including 21 years of age: 2,500 International Units/m². For intramuscular administration limit the volume at a single injection site to 2 mL (use multiple sites if greater than 2 mL). Premedicate 30–60 minutes before administration with paracetamol (acetaminophen), an H1-receptor blocker (e.g. diphenhydramine) and an H2-receptor blocker (e.g. famotidine) to reduce infusion and hypersensitivity reactions. Observe patients for 1 hour after administration. Dose modifications/holds required for infusion or hypersensitivity reactions, thrombosis, pancreatitis, haemorrhage and hepatotoxicity. Dose is expressed per body surface area (International Units/m²), not a clean per-kg paediatric dose.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

History of serious hypersensitivity reactions, including anaphylaxis, to pegaspargase or to any of the excipients
History of serious thrombosis with prior L-asparaginase therapy
History of pancreatitis, including pancreatitis related to prior L-asparaginase therapy
History of serious haemorrhagic events with prior L-asparaginase therapy
Severe hepatic impairment

Side effects

Hypoalbuminaemia
Elevated transaminases
Febrile neutropenia
Hypertriglyceridaemia
Hyperglycaemia

Interactions

Glucocorticoids — pegaspargase may increase the risk of glucocorticoid-induced toxicities (e.g. osteonecrosis) through a potential increase in dexamethasone exposure

Clinical monograph

How it works

It is a pegylated form of L-asparaginase that depletes circulating asparagine, which leukaemic lymphoblasts cannot synthesise, thereby starving them of this amino acid and inhibiting protein synthesis.

Prescribing in practice

Serious hypersensitivity and anaphylaxis can occur, so it must be given where resuscitation facilities are available and patients observed after administration.
It can cause pancreatitis, coagulation disturbances with thrombosis or bleeding, and hyperglycaemia, all of which require monitoring.
Hepatotoxicity may occur and treatment should be administered only under specialist supervision.

Monitoring

Monitor coagulation parameters, blood glucose, amylase or lipase and liver function during treatment.

Counselling the patient

Report severe abdominal pain, excessive thirst, or any rash, swelling or breathing difficulty.
Attend for the blood tests arranged to check clotting and blood sugar.

Evidence & guidelines

Use is guided by the Summary of Product Characteristics and established paediatric and adult leukaemia treatment protocols.

Reference: NICE TA408; UKALL trial protocols; ESMO; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways