Elranatamab-bcmm (Elrexfio™)

Author: Karen Arnold-Korzeniowski, MSN RN
Content Contributor: Oxana Megherea, PharmD
Last Reviewed: August 24, 2023

Pronounce: EL-ra-NAT-a-mab

Classification: Bispecific T-cell engager

About: Elranatamab-bcmm (Elrexfio™)

Elranatamab-bcmm (Elrexfio™) is a bispecific B-cell maturation antigen (BCMA)-directed T-cell engaging antibody used to treat some forms of multiple myeloma (MM). Elranatamab-bcmm activates your T-cells (part of your immune system) by connecting the CD3 antigen (found on T cells) with BCMA, which is found on the surface of MM cells. The redirected T-cells kill multiple myeloma cells in various ways.

How to Take Elranatamab-bcmm (Elrexfio™)

This medication is given as a subcutaneous (SubQ) injection. This means it is given as a shot into the fatty layer right under your skin. This medication is often given in your belly.

Your dose depends on what day you are in your treatment cycle and if you had any treatment delays due to adverse reactions. You may need to stay in the hospital during your step-up doses when beginning this medication, to watch for side effects. You may be given "pre-medications" before the injection to prevent side effects. These can include acetaminophen, dexamethasone, and diphenhydramine.

This medication is available only through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS), called ELREXFIO REMS. This program is in place due to the risks of cytokine release syndrome (CRS) and neurologic toxicity, including immune effector cell–associated neurotoxicity syndrome (ICANS). Prescribers and pharmacies/healthcare settings must be certified with the program by enrolling and completing training. Prescribers must counsel patients on CRS and neurotoxicity and complete and provide patients with a Patient Wallet Card to carry with them at all times. This card lists symptoms of potential side effects of this medication. If you are having any of the symptoms listed on the card, you should get medical treatment right away.

Possible Side Effects of Elranatamab-bcmm

There are a number of things you can do to manage the side effects of elranatamab-bcmm. 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:

Cytokine Release Syndrome (CRS)

CRS can occur. T cells are activated by this medication, causing them to release many cytokines. The cytokines cause an inflammatory response in the body. This reaction, if left untreated, can be very dangerous. Signs and symptoms may be fever, having a hard time breathing, chills, low blood pressure, fast heart rate, headache, and higher levels of liver enzymes in your blood. Your care team will monitor you closely for CRS while you are receiving this medication. You should call your provider right away if you have any signs or symptoms of CRS so that treatment can be started.

Neurologic Toxicity including ICANS

Neurological (brain) toxicities, such as aphasia (being unable to understand speech or speak normally), a change in mental status, encephalopathy (lack of blood flow and oxygen to your brain), and seizures have happened in patients who received this medication. Other neurological side effects can include headaches, neuropathy (numbness or tingling), and/or changes to your motor skills (loss of control, often of the arms or legs). Your care team will be monitoring you very closely for any changes in your mental status.

There is also a risk of Guillain-Barré syndrome with this medication, where your immune system attacks nerves in your body. If you have new or worsening numbness or tingling that starts in your lower body and continues to your upper body, confusion, weakness, or problems with balance, call your care team right away.

Infection and Low White Blood Cell Count (Leukopenia/Neutropenia)

This medication can cause life-threatening infections, with or without a decrease in white blood cell counts.

White blood cells (WBC) are important for fighting infection. While receiving treatment, your WBC count can drop, putting you at a higher risk of getting an infection. You should let your doctor or nurse know right away if you have a fever (temperature greater than 100.4 °F or 38°C), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.

Tips to preventing infection:

  • Washing hands, both yours and your visitors, is the best way to prevent the spread of infection.
  • Avoid large crowds and people who are sick (i.e.: those who have a cold, fever, or cough or live with someone with these symptoms).
  • When working in your yard, wear protective clothing including long pants and gloves.
  • Do not handle pet waste.
  • Keep all cuts or scratches clean.
  • Shower or bathe daily and perform frequent mouth care.
  • Do not cut cuticles or ingrown nails. You may wear nail polish, but not fake nails.
  • Ask your oncology care team before scheduling dental appointments or procedures.
  • Ask your oncology care team before you, or someone you live with has any vaccinations.

Low Red Blood Cell Count (Anemia)

Your red blood cells are responsible for carrying oxygen to the tissues in your body. When the red cell count is low, you may feel tired or weak. You should let your oncology care team know if you experience any shortness of breath, difficulty breathing, or pain in your chest. If the count gets too low, you may receive a blood transfusion.

Low Platelet Count (Thrombocytopenia)

Platelets help your blood clot, so when the count is low you are at a higher risk of bleeding. Let your oncology care team know if you have any excess bruising or bleeding, including nose bleeds, bleeding gums, or blood in your urine or stool. If the platelet count becomes too low, you may receive a transfusion of platelets.

  • Do not use a razor (an electric razor is fine).
  • Avoid contact sports and activities that can result in injury or bleeding.
  • Do not take aspirin (salicylic acid), non-steroidal, anti-inflammatory medications (NSAIDs) such as Motrin/Advil (ibuprofen), Aleve (naproxen), Celebrex (celecoxib) etc. as these can all increase the risk of bleeding. Please consult with your healthcare team regarding use of these agents and all over the counter medications/supplements while on therapy.
  • Do not floss or use toothpicks and use a soft-bristle toothbrush to brush your teeth.


Fatigue is very common during cancer treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on cancer treatment, and for a period after, you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team for helpful tips on dealing with this side effect.

Injection Site Reactions

You may have pain, redness, itching, bruising, tenderness, or swelling at the site of the injection.


Your oncology care team can recommend medications to relieve diarrhea. Also, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole-grain breads, cereals, and seeds. Soluble fiber is found in some foods and absorbs fluid, which can help relieve diarrhea. Foods high in soluble fiber include applesauce, bananas (ripe), canned fruit, orange sections, boiled potatoes, white rice, products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses of non-alcoholic, un-caffeinated fluid a day to prevent dehydration.

Muscle or Joint Pain/Aches

Your healthcare provider can recommend medications and other strategies to help relieve pain.

Decrease in Appetite or Taste Changes

Nutrition is an important part of your care. Cancer treatment can affect your appetite and, in some cases, the side effects of treatment can make eating difficult. Ask your oncology care team about nutritional counseling services at your treatment center to help with food choices.

  • Try to eat five or six small meals or snacks throughout the day, instead of 3 larger meals.
  • If you are not eating enough, nutritional supplements may help.
  • You may experience a metallic taste or find that food has no taste at all. You may dislike foods or beverages that you liked before receiving cancer treatment. These symptoms can last for several months or longer after treatment ends.
  • Avoid any food that you think smells or tastes bad. If red meat is a problem, eat chicken, turkey, eggs, dairy products, and fish without a strong smell. Sometimes cold food has less of an odor.
  • Add extra flavor to meat or fish by marinating it in sweet juices, sweet and sour sauce, or dressings. Use seasonings like basil, oregano, or rosemary to add flavor. Bacon, ham, and onion can add flavor to vegetables.


Some patients may develop a rash, scaly skin, or red itchy bumps. Use an alcohol-free moisturizer on your skin and lips; avoid moisturizers with perfumes or scents. Your oncology care team can recommend a topical medication if itching is bothersome. If your skin does crack or bleed, be sure to keep the area clean to avoid infection. Be sure to notify your oncology care team of any rash that develops, as this can be a reaction. They can give you more tips on caring for your skin.

Nausea and/or Vomiting

Talk to your oncology care team so they can prescribe medications to help you manage nausea and vomiting. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy, or acidic foods (lemons, tomatoes, oranges). Try saltines, or ginger ale to lessen symptoms. Call your oncology care team if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.

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.

Kidney Toxicity

This medication can cause kidney toxicity, which your oncology team will monitor for using blood tests to check your creatinine level. Notify your care team if you notice decreased urine output, dark colored urine, blood in the urine, or swelling in the ankles.

Electrolyte Abnormalities

This medication can affect the normal levels of electrolytes (potassium, magnesium, sodium, etc.) in your body. Your levels will be monitored using blood tests. If your levels become too low, your care team may prescribe specific electrolytes to be given by IV or taken by mouth. Do not take any supplements without first consulting with your care team.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant while on this medication. Effective birth control is necessary during treatment and for at least 4 months after the last dose. 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 and for at least 4 months after the last dose.