Calaspargase pegol-mknl (Asparlas®)

Author: Marisa Healy, BSN, RN
Last Reviewed: December 13, 2023

Pronounce: kal-AS-par-jase PEG-ol mknl

Classification: Enzyme, Antineoplastic agent

About: Calaspargase pegol-mknl (Asparlas®)

All cells in the body need the amino acid asparagine to survive. Normal white blood cells can make their own asparagine, but cancerous white blood cells cannot. Casparaginase pegol-mknl is an enzyme that speeds up the breakdown of asparagine in the blood into aspartic acid and ammonia. This reduces the level of asparagine in the body. Without asparagine available in the body, the cancer cells die.

How to Take Casparaginase pegol-mknl

Casparaginase pegol-mknl is given by intravenous (into a vein) infusion. The dose is based on your weight and how often you receive the medication will depend on your treatment plan. It is given in combination with other medications.

Possible Side Effects

There are a number of things you can do to manage the side effects of casparaginase pegol-mknl. Talk to your care team about these recommendations. They can help you decide what will work best for you. These are some of the most common or important side effects:

Allergic Reaction

In some cases, patients can have an allergic reaction to this medication. Signs of a reaction can include shortness of breath or difficulty breathing, chest pain, rash, flushing, itching, swelling at the injection site, or a decrease in blood pressure. If you notice any changes in how you feel during the infusion, let your nurse know immediately.

Liver Toxicity

This medication can cause liver toxicity, which your oncology care team may monitor for using blood tests called liver function tests. Notify your healthcare provider if you notice yellowing of the skin or eyes, your urine appears dark or brown, or you have pain in your abdomen, as these can be signs of liver toxicity.

Less common, but important side effects

  • Pancreatitis: This medication can cause an inflammation of the pancreas, called pancreatitis. Your care provider may order blood tests to check how your pancreas is functioning. Call your healthcare team if you experience abdominal pain, nausea, or vomiting.
  • Blood Clots: Calaspargase pegol-mknl can increase the risk of blood clots. These clots can occur anywhere in the body. Symptoms of blood clots can include severe headache, swelling in the arm or leg, chest pain, or shortness of breath, among others. If you experience any unusual symptoms, you should contact your healthcare provider immediately or go to an emergency room.
  • Bleeding: This medication can impact the ability of your blood to clot normally. This can cause excessive bleeding. Your healthcare team will monitor your blood clotting ability during and after treatment. Notify your healthcare team or go to the emergency room immediately if you experience uncontrolled bleeding; including blood in the urine, black or bloody stool, nosebleeds, or other bleeding.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. Effective birth control is necessary during treatment and for at least 3 months after treatment. This medication can interact with oral birth control pills, so other methods of birth control should be used. Even if your menstrual cycle stops or you believe you are not producing sperm, you could still be fertile and conceive. You should not breastfeed during treatment with this medication and for 3 months after the last dose.


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