Pegaspargase
Other antineoplastics (differentiating agents, asparaginases, proteasome inhibitors)
Other antineoplastics (differentiating agents, asparaginases, proteasome inhibitors)High alert
An error with this medicine can cause serious harm: double checks and protocols are used.
Asparaginase bound to polyethylene glycol: it lasts longer and causes fewer allergies than the native enzyme; used in ALL, including first-line.
Also called: PEG-asparaginase
Quick facts
- Group
- Other antineoplastics (differentiating agents, asparaginases, proteasome inhibitors)
- Target
- Plasma L-asparagine (the drug is a pegylated L-asparaginase)
- Used for
- Acute lymphoblastic leukaemia
- Key effects
- Nausea · Fever · Allergic reactions
- Monitor
- Allergic signs after each dose · Glucose
- ATC
- L01XX24
No doses: the clinician sets them by the current guideline.
Mechanism of action
The crystal shows the Escherichia coli L-asparaginase II enzyme without its polyethylene glycol chains, with aspartate (the reaction product) in the active site.
Pegaspargase is Escherichia coli asparaginase linked to polyethylene glycol chains. Like the native enzyme it breaks down plasma asparagine, which leukaemic lymphoblasts cannot make in sufficient amounts, so their protein synthesis fails and they die. The polyethylene glycol shields the protein from the immune system and from clearance: it stays in the blood much longer and causes antibodies and allergy less often.
- Pegylated enzyme circulates for days
- Hydrolyses plasma asparagine
- Lymphoblasts run out of asparagine
- Protein synthesis fails: leukaemic cells die
Indications
- Acute lymphoblastic leukaemia, as part of combination chemotherapy, first-line or after allergy to native asparaginase. Acute leukaemia (AML and ALL) →
Adverse effects
Common
- Nausea, vomiting, diarrhoea
- Fever, tiredness, dizziness
- Allergic reactions (less often than with native asparaginase)
- High glucose
- Raised liver tests
Contraindications
- Previous serious allergy to pegaspargase
- Previous pancreatitis, serious thrombosis or serious bleeding during asparaginase treatment
- Severe liver disease
Key interactions
- Methotrexate
- Asparaginase given shortly after methotrexate cancels methotrexate's antitumour effect; the order is fixed in the protocol.
- Highly protein-bound drugs
- Low albumin can raise their free fraction.
What is monitored
- Allergic signs after each dose
- Lipase or amylase and abdominal pain
- Glucose
- Liver tests and albumin
- Coagulation tests and signs of clots or bleeding
Administration and safety
- Look-alike products: pegaspargase, native asparaginase and Erwinia asparaginase have different schedules and are not interchangeable.
- Given intramuscularly or as an intravenous infusion over a set time, never as a push.
- Observe the patient after the dose with anaphylaxis drugs at hand.
- Hazardous drug: prepared and disposed of following cytotoxic handling procedures.
Pregnancy and breastfeeding
May harm the fetus; pregnancy is avoided and non-hormonal contraception is preferred during treatment.
Nursing care
- Watch for hives, wheeze or low blood pressure after the dose.
- Check glucose; ask about thirst and frequent urination.
- Ask about abdominal pain spreading to the back, and about headache or swelling of a limb (clots).
- Teaching: report these symptoms promptly, since the drug stays in the body for weeks.
Pharmacokinetics
- Absorption
- Intramuscular injection or intravenous infusion.
- Distribution
- Stays mainly in the plasma.
- Half-life
- About 6 to 7 days, far longer than the native enzyme; one dose depletes asparagine for weeks.
Test yourself
Think of the answer, then tap the question to see it.
What advantage does pegylation give asparaginase?
A much longer half-life and less immunogenicity (fewer allergies and neutralising antibodies).
Which abdominal complication is screened for during pegaspargase treatment?
Acute pancreatitis.
Why can glucose rise on pegaspargase?
Asparagine depletion reduces protein (including insulin) synthesis.
Connections
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Pegaspargase Injection: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2012); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026); eEML - Electronic Essential Medicines List (World Health Organization, 2025).
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Representative model, for educational purposes only.