Darzalex Faspro (daratumumab/hyaluronidase-fihj) is a brand-name prescription medication. It’s approved by the Food and Drug Administration (FDA) to treat the following in adults in certain situations:

Multiple myeloma. This is a type of blood cancer. Your doctor may prescribe Darzalex Faspro alone or in combination with other medications for multiple myeloma. Keep in mind that some side effects may be due to these other drugs rather than Darzalex Faspro.

Darzalex Faspro may be prescribed long term for multiple myeloma as long as the drug is safe and effective for you.

Light-chain amyloidosis. Your doctor may prescribe Darzalex Faspro if you have been recently diagnosed with a rare condition called light-chain amyloidosis. (It’s caused by a buildup of a protein called amyloid, which can lead to organ damage.) For this purpose, Darzalex Faspro is prescribed with other medications. Keep in mind that some side effects may be due to these other drugs rather than Darzalex Faspro.

Darzalex Faspro may be prescribed for light-chain amyloidosis for up to 2 years, as long as the drug is safe and effective for you.

Here are some fast facts about Darzalex Faspro:

  • Active ingredients: daratumumab and hyaluronidase-fihj, which are biologics
  • Drug class: monoclonal antibody and an endoglycosidase
  • Drug form: solution given as a subcutaneous injection by a healthcare professional
  • FDA approval year: 2020

Like other drugs, Darzalex Faspro can cause side effects. Read on to learn about potential common, mild, and serious side effects.

Darzalex Faspro vs. Darzalex

Darzalex Faspro and Darzalex both treat multiple myeloma. Darzalex Faspro also treats light-chain amyloidosis.

Both Darzalex Faspro and Darzalex contain the active drug daratumumab. Darzalex Faspro also contains hyaluronidase-fihj.

Darzalex Faspro and Darzalex are both given by healthcare professionals. Darzalex Faspro is given as a subcutaneous injection, while Darzalex is given as an IV infusion.

This article focuses on Darzalex Faspro. To learn more about the drug and its uses, talk with your doctor. You can also refer to the Darzalex Faspro prescribing information. For an overview of Darzalex, see this article.

Darzalex Faspro can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who took Darzalex Faspro in clinical trials.

Darzalex Faspro may be used alone to treat multiple myeloma. However, the drug is typically prescribed in combination with other medications for the condition. Darzalex Faspro is prescribed with other drugs to treat light-chain amyloidosis. The side effects listed here may be due to other medications your doctor has prescribed, rather than just Darzalex Faspro.

More common side effects in people who took Darzalex Faspro for multiple myeloma included:

More common side effects in people who took Darzalex Faspro for light-chain amyloidosis included:

  • upper respiratory tract infection, such as the common cold
  • diarrhea
  • swelling in your arms, hands, feet, and legs
  • constipation
  • fatigue

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Darzalex Faspro. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Darzalex Faspro’s prescribing information.

Darzalex Faspro may be used alone to treat multiple myeloma. However, the drug is typically prescribed in combination with other medications for the condition. Darzalex Faspro is prescribed with other drugs to treat light-chain amyloidosis.

The side effects listed here may be due to other medications your doctor has prescribed, rather than just Darzalex Faspro.

Mild side effects that have been reported with Darzalex Faspro include:

These side effects may be temporary, lasting a few days to weeks. If the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect during Darzalex Faspro treatment and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.

Darzalex Faspro may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Darzalex Faspro’s prescribing information.

Darzalex Faspro may be used alone to treat multiple myeloma. However, the drug is typically prescribed in combination with other medications for the condition. Darzalex Faspro is prescribed with other drugs to treat light-chain amyloidosis. The side effects listed here may be due to other medications your doctor has prescribed, rather than just Darzalex Faspro.

If you develop serious side effects during Darzalex Faspro treatment, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects of Darzalex Faspro that have been reported and their symptoms include:

  • Peripheral neuropathy (nerve damage that causes numbness, pain, or tingling in your arms or legs). Symptoms can include:
    • burning pain
    • increased sensitivity
    • numbness or tingling in your arms or legs
    • weakness in your hands or legs
  • Pneumonia. Symptoms can include:
    • chest pain
    • cough, which often includes phlegm (mucus)
    • shortness of breath
  • Blood cell disorders.*
  • Severe injection reactions.*
  • Heart problems.*
  • Allergic reaction.*

* For more information about this side effect, see “Side effect specifics” below.

Darzalex Faspro may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Will my doctor prescribe medication to help prevent side effects from Darzalex Faspro?

Your doctor will likely prescribe certain medications to help prevent side effects from Darzalex Faspro.

Darzalex Faspro injections can cause certain reactions, including shortness of breath and wheezing. Medications given before you receive an injection may help prevent these effects. These are referred to as premedications.

You may also receive medications after an injection that may help prevent side effects. These are known as postmedications.

For more information, see “Injection reactions” in the “Side effect specifics” section below.

Can Darzalex Faspro cause joint pain?

It’s possible that treatment with Darzalex Faspro can cause joint pain. This was not one of the more common side effects of the drug. However, people who took Darzalex Faspro in clinical trials did report joint pain. The trials included people who took the medication for multiple myeloma or light-chain amyloidosis. Joint pain occurred more often in people who received treatment for light-chain amyloidosis.

Keep in mind that Darzalex Faspro was prescribed with other medications to treat multiple myeloma in many of these trials. The drug was also prescribed with other medications to treat light-chain amyloidosis. In these settings, it can be difficult to determine which medication caused the side effect.

If you have joint pain while receiving Darzalex Faspro, talk with your doctor. They may recommend a treatment such as a topical cream or ointment. (With a topical treatment, you apply it to your skin.) If your joint pain is severe or won’t go away, they may suggest other options for your condition.

Learn more about some of the side effects that Darzalex Faspro may cause.

Blood cell disorders

Treatment with Darzalex Faspro will likely cause blood cell disorders. Many people who took the medication in clinical trials reported at least one blood cell disorder.

In most of these trials, Darzalex Faspro was prescribed with other medications to treat multiple myeloma or light-chain amyloidosis. Some of these other drugs are known to cause blood cell disorders. In clinical trial settings, it can be difficult to determine which medication caused the side effect.

Blood cell disorders reported in clinical trials of Darzalex Faspro included:

Symptoms can vary depending on the blood cell affected. Some people may not have symptoms, especially when these side effects are mild. However, some symptoms to watch for include:

  • bleeding more than usual after minor cuts or scrapes
  • fever or chills
  • frequent infections or infections that won’t go away
  • runny nose
  • shortness of breath

* This blood cell disorder can make you more likely to develop an infection than usual.

What you can do

Your doctor will order lab tests to check your blood cell levels throughout your treatment with Darzalex Faspro. If the results show that your levels are too low, your doctor may pause your treatment until the levels return to normal. Depending on which type of blood cell level is low, they may also recommend treatment.

Injection reactions

It’s possible to have injection reactions as a side effect from Darzalex Faspro. These reactions may be mild or serious.

Mild injection reactions

Mild injection reactions that may occur at or near the site where the drug was injected can include:

  • bleeding
  • bruising
  • itchiness
  • pain
  • skin rash
  • skin redness or discoloration

These reactions usually occur within 24 hours of having a Darzalex Faspro injection. In some cases, they can occur later.

Other mild reactions to a Darzalex Faspro injection can include a stuffy nose, cough, nausea, and sore throat.

Serious injection reactions

Serious injection reactions to Darzalex Faspro are not common. In extreme cases, they can be life threatening or, in rare situations, fatal. Serious injection reactions are most likely to occur after your first Darzalex Faspro dose. The risk decreases with future injections.

Serious injection reactions happen on average about 3 hours following a dose. However, they may occur within minutes. In most cases, they take place on the same day as the injection. In rare situations, the reactions happen later on.

Severe injection reactions to Darzalex Faspro can include:

* For details, see “Allergic reaction” below.

What you can do

Your doctor will likely prescribe medication to help prevent injection reactions. These include premedications, which you receive before your Darzalex Faspro injections. Your doctor may also prescribe postmedications. You receive these following an injection of the drug.

Premedications are usually given 1 to 3 hours before each Darzalex Faspro dose. They typically include:

Postmedications may include a corticosteroid, such as methylprednisolone.

Your doctor will monitor you closely for any reactions you may have after your Darzalex Faspro injection. Be sure to talk with them right away if you have a reaction any time after you receive your dose.

If you have a severe or life threatening reaction to a Darzalex Faspro injection, your doctor will likely stop your treatment.

Heart problems

Treatment with Darzalex Faspro may cause heart problems, but this is not common.

Heart problems reported by people who took Darzalex Faspro in clinical trials included:

Symptoms of heart problems due to Darzalex Faspro can include:

  • chest pain or discomfort
  • fast or irregular heartbeat
  • fatigue
  • heart palpitations
  • shortness of breath
  • swelling in your ankles, feet, or lower legs

It’s important to note that other medications you receive with Darzalex Faspro may affect your risk of heart problems. For example, heart failure was reported in people who received Darzalex Faspro in combination with dexamethasone and Kyprolis (carfilzomib) to treat multiple myeloma. Carfilzomib is known to cause heart problems. People who took Darzalex Faspro with different medications to treat multiple myeloma did not report heart failure.

Both heart failure and cardiac arrest were reported in people who took Darzalex Faspro for light-chain amyloidosis. These side effects occurred more often in this group than in people who took the drug to treat multiple myeloma. Heart failure and cardiac arrest were, in extreme cases, fatal in people who took Darzalex Faspro for light-chain amyloidosis.

What you can do

Your doctor will monitor you for heart problems during treatment with Darzalex Faspro. If you notice symptoms, such as those listed above, talk with your doctor right away. They’ll likely want to examine you. Depending on your side effects and how serious they are, your doctor may recommend switching you to a different treatment for your condition.

If you have an existing heart problem, see “Precautions for Darzalex Faspro” below for more information.

Swelling in arms, hands, feet, and legs

Swelling in arms, hands, feet, and legs is possible with Darzalex Faspro. This side effect was more common in people who received the drug for light-chain amyloidosis than for multiple myeloma.

It’s important to note that this swelling can sometimes be a symptom of heart failure, which Darzalex Faspro may cause in rare cases.

If you’re older than age 65 years and receive Darzalex Faspro, you may have an increased risk of swelling in your arms, hands, feet, and legs.

What you can do

If you notice swelling in your arms, hands, feet, or legs while receiving Darzalex Faspro, it’s important to talk with your doctor right away. This is because the swelling could signal heart failure.

Your doctor will likely want to examine your symptoms in person. They may recommend treatment, such as a diuretic (water pill). If the swelling is bothersome or appears to be related to heart problems, they may have you stop receiving Darzalex Faspro.

Allergic reaction

As with most drugs, Darzalex Faspro can cause an allergic reaction in some people. However, this was not common in clinical trials of the medication.

Darzalex Faspro is given as an injection, and it’s possible to have reactions to the injections. One type of reaction is a severe allergic reaction called anaphylaxis, which can be life threatening. To learn more, see “Injection reactions” above.

Symptoms of allergic reactions can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your lips, eyelids, feet, or hands
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep receiving Darzalex Faspro. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Be sure to talk with your doctor about your health history before you receive Darzalex Faspro. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:

COPD and other breathing problems. Darzalex Faspro injections can cause certain reactions, including shortness of breath and wheezing. Premedications* may help prevent these effects. If you receive Darzalex Faspro and have COPD or another breathing problem, you may have an increased risk of these reactions. So, your doctor may prescribe additional premedications. Your doctor can tell you more about Darzalex Faspro and breathing problems.

Heart problems. Before receiving Darzalex Faspro, be sure to tell your doctor about any heart problems you have, such as heart failure. This is especially important if you’re having treatment for light-chain amyloidosis. Darzalex Faspro can cause serious heart problems, including heart rhythm changes and heart failure. These problems are likely to occur more than usual if you receive Darzalex Faspro for light-chain amyloidosis.

Due to the risk of serious heart problems, doctors typically will not prescribe Darzalex Faspro to treat light-chain amyloidosis if you have severe heart failure.

If you have a heart problem, your doctor can determine whether Darzalex Faspro is right for you.

Hepatitis B. Tell your doctor if you have or have had an infection called hepatitis B. Darzalex Faspro can reactivate the virus that causes hepatitis B. This means the virus could cause symptoms again. If you have had hepatitis B, your doctor will likely prescribe medication to help prevent the virus from becoming active again. If you currently have hepatitis B, your doctor will usually treat it before you take Darzalex Faspro. They can tell you more.

Shingles. Tell your doctor if you have or have had an infection called shingles. Darzalex Faspro can reactivate the virus that causes shingles. This means the virus could cause symptoms again. If you have had shingles, your doctor will likely prescribe medication to help prevent the virus from becoming active again. If you currently have shingles, your doctor will usually treat it before you take Darzalex Faspro. They can give you additional information.

Allergic reaction. If you’ve had an allergic reaction to Darzalex Faspro or any of its ingredients, your doctor will likely not prescribe Darzalex Faspro. Ask your doctor what other medications may be better options for you.

* For more information about premedications, see “Injection reactions” in the “Side effect specifics” section above.

Alcohol use with Darzalex Faspro

There’s no known interaction between consuming alcohol and receiving Darzalex Faspro. However, Darzalex Faspro is often given with other medications that may interact with alcohol.

If you drink alcohol, talk with your doctor about whether it’s safe to drink during your treatment.

Pregnancy and breastfeeding while receiving Darzalex Faspro

Here’s some information about pregnancy, breastfeeding, and Darzalex Faspro.

Pregnancy. It’s unknown whether it’s safe to receive Darzalex Faspro while pregnant. There have not been clinical trials of pregnant people who took the medication. However, it’s thought that Darzalex Faspro could cause side effects in a child born to someone who took the medication during pregnancy.

In addition, some of the medications that doctors may prescribe with Darzalex Faspro to treat multiple myeloma are known to cause severe harm to a pregnancy. These medications are Revlimid (lenalidomide), Pomalyst (pomalidomide), and Thalomid (thalidomide). They should not be taken while pregnant. Your doctor can give you more information.

Breastfeeding. It’s also unknown whether it’s safe to breastfeed during Darzalex Faspro treatment. Certain medications that may be prescribed with Darzalex Faspro to treat multiple myeloma may cause harmful side effects in a child who is breastfed. These medications are lenalidomide, pomalidomide, and thalidomide.

Talking with your doctor. If you’re pregnant or planning a pregnancy, talk with your doctor. You should also talk with them if you’re breastfeeding or thinking about it. They can advise you on the right treatment for you and feeding options for your child.

In rare cases, Darzalex Faspro can cause serious side effects. Talk with your doctor right away if you have symptoms of a serious side effect. You should also talk with them immediately if you become pregnant during Darzalex Faspro treatment.

If you’d like to learn more about Darzalex Faspro, talk with your doctor or pharmacist. They can help answer any questions you have about side effects of the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.