Oncaspar (Pegaspargase)

What Is Oncaspar and What Is It Used For?

Oncaspar (pegaspargase) is an enzyme-based cancer medicine used to treat acute lymphoblastic leukemia (ALL). It depletes the amino acid asparagine from the bloodstream, causing leukemic cells that depend on external asparagine to die.

Oncaspar contains the active substance pegaspargase, which is a pegylated form of the enzyme L-asparaginase. L-asparaginase has been a cornerstone of ALL treatment protocols since the 1960s. The pegylation process – the attachment of polyethylene glycol (PEG) molecules to the native enzyme – extends the drug’s half-life significantly, allowing for less frequent dosing while maintaining therapeutic asparagine depletion. The half-life of pegaspargase is approximately 5.5 days, compared with roughly 1 day for native E. coli L-asparaginase.

The mechanism of action is elegantly simple. Asparagine is a non-essential amino acid that most normal cells can synthesize through an enzyme called asparagine synthetase. However, many leukemic lymphoblasts lack sufficient asparagine synthetase activity and therefore depend on circulating asparagine for their protein synthesis and survival. By administering pegaspargase, which rapidly hydrolyzes asparagine to aspartic acid and ammonia, the drug effectively starves these cancer cells of a critical building block, leading to inhibition of protein synthesis and ultimately cell death.

Oncaspar is approved for the treatment of acute lymphoblastic leukemia (ALL) in patients from birth through to adulthood. ALL is a type of blood cancer in which immature white blood cells – called lymphoblasts – proliferate uncontrollably in the bone marrow and blood. This uncontrolled growth crowds out normal blood cells, leading to anemia, susceptibility to infections, and abnormal bleeding. ALL is the most common childhood cancer, accounting for approximately 25–30% of all pediatric malignancies, and also occurs in adults, although with generally poorer outcomes.

Oncaspar is never used as a standalone therapy. It is always administered as part of multi-agent chemotherapy regimens, typically during the induction and consolidation phases of ALL treatment. Common regimens pair pegaspargase with corticosteroids (such as dexamethasone or prednisone), vincristine, anthracyclines, and other cytotoxic agents. The inclusion of asparaginase-based therapy in modern ALL protocols has been a key factor in the dramatic improvement in cure rates for childhood ALL, which now exceed 90% in many developed countries.

The marketing authorization for Oncaspar is held by Les Laboratoires Servier (Suresnes, France). It has received regulatory approval from the European Medicines Agency (EMA) and has been available for clinical use in the European Union and other markets. In the United States, pegaspargase is also marketed and has been an integral component of Children’s Oncology Group (COG) and other cooperative group treatment protocols for decades.

What Should You Know Before Receiving Oncaspar?

Oncaspar is contraindicated in patients with a history of severe pancreatitis, serious blood clots, or severe hemorrhage from prior asparaginase treatment. Tell your doctor about all medical conditions, especially liver disease, bleeding disorders, and current medications.

Contraindications

You must not receive Oncaspar if any of the following apply to you:

• Allergy to pegaspargase – if you are allergic to pegaspargase or any of the other ingredients in the medicine (listed in the contents section below).
• Severe liver disease – significant hepatic impairment may prevent safe metabolism and elimination of the drug.
• History of pancreatitis – if you have ever had inflammation of the pancreas, whether related to asparaginase therapy or from other causes.
• Severe hemorrhage from prior asparaginase – if a previous course of any asparaginase product caused serious bleeding.
• Severe thrombosis from prior asparaginase – if you have experienced blood clots following treatment with any form of asparaginase.

If you are a parent or guardian of a child being treated with Oncaspar, inform the doctor if any of these conditions apply to your child.

Warnings and Precautions

Talk to your doctor before receiving Oncaspar. This medicine may not be suitable for you in the following situations:

• Prior hypersensitivity to other asparaginase forms – if you have had serious allergic reactions to other forms of asparaginase (e.g., native E. coli L-asparaginase or Erwinia asparaginase), such as itching, flushing, or swelling of the airways, severe reactions to Oncaspar can still occur.
• Bleeding disorders or thrombotic history – Oncaspar can affect blood coagulation factors, increasing the risk of both hemorrhage and blood clot formation. Patients with pre-existing coagulopathies require particularly close monitoring.
• Fever or active infection – this medicine can make you more susceptible to infections by reducing your white blood cell count. If you develop fever during treatment, contact your medical team immediately.
• Poor liver function – hepatotoxicity is a recognized risk with Oncaspar, especially when used in combination with other chemotherapy agents. Severe, life-threatening, and potentially fatal cases of hepatic veno-occlusive disease (sinusoidal obstruction syndrome) have been reported.
• Central nervous system effects – when used in combination chemotherapy regimens, Oncaspar may contribute to central nervous system toxicity, including somnolence, confusion, and in rare cases, posterior reversible encephalopathy syndrome (PRES/RPLS).
• Abdominal pain – pancreatitis, which in certain cases has been fatal, can occur during treatment with Oncaspar. Report any severe abdominal pain immediately to your doctor.

Monitoring During Treatment

During administration of Oncaspar, you will be closely monitored for at least one hour after each dose for signs of severe allergic reactions. Medical equipment for treating anaphylaxis (including epinephrine, oxygen, and intravenous steroids) will be immediately available. Regular blood tests will be performed to monitor your blood sugar levels, liver and pancreatic function, and coagulation parameters throughout the treatment course.

Pregnancy and Breastfeeding

Oncaspar should not be used during pregnancy, as its effects on fetal development have not been studied. Your doctor will determine whether the severity of your condition warrants treatment. Women of childbearing potential must use reliable contraception during treatment and for at least 6 months after the final dose. Importantly, oral contraceptives are not effective during Oncaspar treatment due to the drug’s effects on hepatic protein synthesis. Consult your doctor about which contraceptive method is most appropriate for you.

Men must also use effective contraception while they or their partners are undergoing treatment with Oncaspar. It is unknown whether pegaspargase is excreted in breast milk. As a precautionary measure, breastfeeding should be discontinued during treatment and not resumed until after Oncaspar therapy has been completed.

Driving and Operating Machinery

Avoid driving or operating machinery during treatment with Oncaspar, as the medication can cause drowsiness, fatigue, and confusion. These effects can impair your ability to react safely in potentially dangerous situations.

How Does Oncaspar Interact with Other Drugs?

Oncaspar has significant interactions with several drugs including vincristine, methotrexate, anticoagulants, and corticosteroids. Its effects on liver function can alter how other medications are metabolized and eliminated from the body.

Tell your doctor about all medicines you are currently taking, have recently taken, or might take. This is critically important because Oncaspar can increase the side effects of other drugs through its impact on liver function. The liver plays a central role in metabolizing and clearing many medications from the body, and Oncaspar’s hepatotoxic potential can significantly alter these processes.

Major Interactions

Other Important Interactions

• Live vaccines – vaccination with live vaccines should be avoided within three months of completing your leukemia treatment. Immunosuppression from chemotherapy increases the risk of serious vaccine-strain infections.
• NSAIDs (ibuprofen, naproxen) and aspirin – these drugs impair platelet function and, when combined with Oncaspar’s effects on coagulation, can significantly increase the risk of bleeding complications.
• Dipyridamol – impairs blood clotting ability, compounding Oncaspar’s anticoagulant effects.

Oncaspar can also cause changes in liver function that may affect how other medications work. Your doctor will carefully coordinate the timing and dosing of all medications during your chemotherapy regimen to minimize potentially dangerous interactions.

What Is the Correct Dosage of Oncaspar?

Oncaspar dosing is based on body surface area and is determined by your oncologist as part of a multi-agent chemotherapy protocol. It is given as an intramuscular injection or intravenous infusion by healthcare professionals in a hospital setting.

Oncaspar is always prescribed by a physician experienced in the use of cancer chemotherapy drugs. The dosage is calculated based on your age and body surface area (BSA), which is derived from your height and weight. Before each dose, you may receive premedication – a combination of drugs such as antihistamines, corticosteroids, or antipyretics – to reduce the risk of allergic reactions. Your doctor will determine whether premedication is necessary based on your individual risk profile.

Children and Adolescents (Birth to 18 Years)

Adults

Method of Administration

Oncaspar is supplied as a powder that must be reconstituted before use. The reconstituted solution can be administered in two ways:

• Intramuscular (IM) injection – the solution is injected into a large muscle, typically the thigh or buttock. This is the traditional route of administration.
• Intravenous (IV) infusion – the reconstituted solution is diluted in 100 mL of 0.9% sodium chloride or 5% glucose solution and infused over 1 to 2 hours. This route may be preferred when IM injection is not appropriate.

The choice of administration route is determined by the treating physician based on clinical considerations, including the patient’s platelet count (as IM injection carries a risk of hematoma in thrombocytopenic patients) and the specific treatment protocol being followed.

Missed Dose

Since Oncaspar is administered by healthcare professionals in a hospital or clinic setting, missed doses are uncommon. If a scheduled dose is missed or delayed, your doctor will determine the appropriate course of action based on your treatment protocol and overall clinical status. Do not attempt to adjust the dosing schedule on your own.

Overdose

Because Oncaspar is administered by trained medical personnel, overdose is extremely unlikely. In the rare event of an accidental overdose, you will be closely monitored by your medical team and given appropriate supportive treatment. There is no specific antidote for pegaspargase overdose. If you have any concerns, speak with your doctor.

What Are the Side Effects of Oncaspar?

Like all cancer therapies, Oncaspar can cause side effects. The most serious include allergic reactions, pancreatitis, blood clots, liver damage, and hemorrhage. Not everyone experiences side effects, but close monitoring is essential throughout treatment.

The side effects of Oncaspar range from very common to rare. Some side effects are serious and require immediate medical attention, while others are more manageable. It is important to report any new or worsening symptoms to your healthcare team promptly. The frequency categories below are based on clinical trial data and post-marketing surveillance.

Serious Side Effects – Seek Immediate Medical Attention

Other Side Effects

If you experience any side effects, including those not listed here, talk to your healthcare team. You can also report suspected side effects to your national pharmacovigilance authority to help ensure continuous monitoring of the drug’s benefit-risk profile.

How Should Oncaspar Be Stored?

Oncaspar must be stored in a refrigerator at 2°C–8°C and must not be frozen. After reconstitution, the solution should be used immediately or stored at 2°C–8°C for a maximum of 48 hours.

Keep this medicine out of the sight and reach of children. Do not use Oncaspar after the expiry date printed on the label and carton. The expiry date refers to the last day of the indicated month.

• Unopened vials: Store in a refrigerator at 2°C–8°C (36°F–46°F). Do not freeze.
• After reconstitution: Use the solution within 24 hours when stored below 25°C. The reconstituted solution should be clear, colorless, and free of visible particles. Do not use if the solution is cloudy or contains precipitates.
• After dilution for IV infusion: The diluted solution may be stored at 2°C–8°C for up to 48 hours if immediate use is not possible.

Do not dispose of medicines via wastewater or household waste. Ask your pharmacist how to dispose of medicines that are no longer required. These measures will help protect the environment. Oncaspar is for single use only – any unused portion should be discarded according to local regulations for cytotoxic waste.

What Does Oncaspar Contain?

Each vial of Oncaspar contains 3,750 Units of pegaspargase. After reconstitution, the solution provides 750 Units per mL.

Active Ingredient

The active substance is pegaspargase. Each vial contains 3,750 Units of pegaspargase. After reconstitution with 5.2 mL of water for injections, each milliliter of solution contains 750 Units of pegaspargase (750 U/mL).

Inactive Ingredients (Excipients)

• Disodium phosphate heptahydrate
• Sodium dihydrogen phosphate monohydrate
• Sodium chloride
• Sucrose
• Sodium hydroxide (for pH adjustment)
• Hydrochloric acid (for pH adjustment)

This medicine contains less than 1 mmol sodium per dose, meaning it is essentially “sodium-free.”

Appearance

Oncaspar is a white to off-white powder supplied in a glass vial. After reconstitution, the solution is clear, colorless, and free of visible foreign particles. Each package contains one glass vial with 3,750 Units of pegaspargase.

Manufacturer

Oncaspar is marketed by Les Laboratoires Servier (50, rue Carnot, 92284 Suresnes cedex, France). Manufacturing is performed by Les Laboratoires Servier Industrie (905 Route de Saran, 45520 Gidy, France).