Epkinly (epcoritamab-bysp) is a brand-name injectable solution prescribed for diffuse large B-cell lymphoma in some adults. As with other drugs, Epkinly can cause side effects, such as fatigue, muscle or bone pain, and injection site reactions.

Epkinly 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 received Epkinly in clinical trials:

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

Mild side effects that have been reported with Epkinly include:

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.

Note: After the FDA approves a drug, it tracks and reviews side effects of the medication. If you develop a side effect during Epkinly treatment and want to tell the FDA about it, visit MedWatch.

* An allergic reaction is possible after receiving Epkinly. However, it’s not clear whether this side effect occurred in clinical trials. To learn more, see the “Side effect specifics” section below.

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

If you develop serious side effects during treatment with Epkinly, 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 that have been reported and their symptoms include:

* Epkinly has a boxed warning for this side effect. This is the most serious warning from the FDA. To learn more, see the “Side effect specifics” section below.
† For more information about this side effect, see “Side effect specifics” below.

Learn more about some of the side effects that Epkinly may cause. To find out how often side effects occurred in clinical trials, see the prescribing information for Epkinly.

Risk of cytokine release syndrome

Epkinly has a boxed warning for the risk of cytokine release syndrome (CRS). A boxed warning is the most serious warning from the FDA. The purpose of a boxed warning is to alert patients and doctors to the risks of treatment with a medication.

CRS can occur if your body has a strong reaction to Epkinly and releases excess cytokines. These are immune system proteins that cause inflammation. CRS can be mild to severe and even life threatening in some cases. However, people who develop CRS typically recover in about 1–2 weeks with treatment.

CRS was common in Epkinly’s clinical trials. Most cases were mild but some were more severe. In these trials, there were no reported deaths from CRS. The condition most often occurred after receiving a dose in the first month of treatment.

Symptoms of CRS may include:

It’s important to be aware of CRS symptoms so that you (or a caregiver) can tell your doctor right away if you develop any.

What you can do

To help prevent CRS, your doctor will slowly increase your dosage of Epkinly. This is called a step-up dosing schedule,* and it helps your body adjust to the medication. In addition, your doctor may recommend certain medications to help decrease your risk of developing CRS. Examples include acetaminophen (Tylenol) or diphenhydramine (Benadryl).

Due to the risk of CRS, you’ll stay in the hospital for at least 24 hours after your first full dose of Epkinly. Your care team will monitor you for symptoms of CRS and provide treatment as necessary. This may include medications to reduce inflammation, such as corticosteroids.

If you experience CRS symptoms any other time, be sure to tell your doctor right away. They’ll determine whether CRS is causing your symptoms. If you have CRS, your doctor will pause your Epkinly doses. In some cases, they may recommend stopping Epkinly treatment. For more information about CRS and Epkinly treatment decisions, talk with your doctor.

* To learn about Epkinly’s dosing schedule, you can refer to the “Dosage” section of this article.

Risk of immune effector cell-associated neurotoxicity syndrome

Epkinly also has a boxed warning for the risk of immune effector cell-associated neurotoxicity syndrome (ICANS). This is a serious condition that causes brain and nerve symptoms.

Some people developed ICANS during clinical trials of Epkinly. In these trials, most cases were mild, but some were severe. ICANS can be life threatening. There was one reported death from ICANS in the drug’s clinical trials.

ICANS can occur within a week of receiving a dose of Epkinly but may also occur later during treatment. With supportive care, symptoms typically ease in a few days. Symptoms of ICANS may include:

What you can do

If you experience any of the symptoms above during Epkinly treatment, be sure to tell your doctor. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Due to the risk of ICANS, you’ll receive your first dose of Epkinly during a hospital stay of at least 24 hours. Your care team will monitor you for symptoms of ICANS and provide any necessary treatment.

If you have ICANS, your doctor will likely pause your Epkinly doses until you recover. In some cases, they may stop Epkinly treatment. Talk with your doctor if you have concerns about developing ICANS during your treatment.

Allergic reaction

As with most drugs, Epkinly can cause an allergic reaction in some people. However, it’s not clear whether this side effect occurred in clinical trials.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • 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 continue with Epkinly treatment. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Before starting Epkinly, talk with your doctor or pharmacist about any other medical conditions that you have or any medications that you take. They can help make sure that Epkinly is safe for you.

Boxed warnings

This drug has boxed warnings about risks of CRS and ICANS. A boxed warning is the most serious warning from the FDA. For details, see the “Side effect specifics” section above.

Other precautions

Be sure to talk with your doctor about your health history before starting Epkinly treatment. This drug may not be the right treatment option for you if you have certain medical conditions or other factors that affect your health. These are considered drug-condition or drug-factor interactions. The conditions and factors to consider include:

Current infection: If you have an infection, tell your doctor before starting Epkinly. This medication may increase your risk of infections, some of which can be serious or even life threatening. If you already have an infection when starting Epkinly, this medication could make your infection worse. Your doctor will likely recommend treating your infection before starting Epkinly.

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

Pregnancy or breastfeeding: If you’re pregnant or breastfeeding your child, Epkinly is not considered safe to receive. Epkinly can cause harm to a developing fetus if received during pregnancy. If you can become pregnant, doctors recommend using birth control during treatment and for at least 4 months after stopping Epkinly. If you become pregnant during treatment, tell your doctor right away.

It’s not known whether the drug may pass into breast milk. For this reason, doctors recommend avoiding breastfeeding during treatment with Epkinly and for at least 4 months after your last dose.

Be sure to tell your doctor if you’re pregnant or breastfeeding. They can let you know about other treatment options for your condition.

Alcohol consumption: If you drink alcohol, Epkinly is likely safe to consume. If you have questions about drinking alcohol during Epkinly treatment, talk with your doctor.

If you’d like to learn more about Epkinly, talk with your doctor or pharmacist. They can help answer any questions you have about side effects from 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.