Elrexfio (elranatamab-bcmm) by Pfizer is used to treat multiple myeloma (MM), which is a type of blood cancer that affects plasma cells made in the bone marrow. Elrexfio is used in adults who have relapsed or refractory multiple myeloma (RRMM) and have tried at least four lines of therapy, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody.

Elrexfio is a B-cell maturation antigen (BCMA) CD3-targeted bispecific antibody (BsAb). Elrexfio is given as a weekly subcutaneous injection, after two step-up doses, until 24 weeks, when treatment becomes every two weeks.

Elrexfio received FDA approval on August 14, 2023,  approval was based on positive results from the Phase 2 MagnetisMM-3 study (NCT04649359) which showed a objective response rate (ORR) of 57.7%.

Elrexfio may cause serious side effects, including

Cytokine Release Syndrome (CRS). CRS is common during treatment with Elrexfio and can also be serious, life-threatening, or can lead to death. Tell your healthcare provider or get medical help right away if you develop any signs or symptoms of CRS, including:

• fever of 100.4 °F (38 °C) or higher
• trouble breathing
• chills
• dizziness or light-headedness
• fast heartbeat
• headache
• increased liver enzymes in your blood. 

See 'Side Effects' for more information about the signs and symptoms of liver problems.

Due to the risk of CRS, you will receive Elrexfio on a “step-up dosing schedule” and should be hospitalized for 48 hours after the first “step-up” dose and for 24 hours after the second “step-up” dose.

During the step-up dosing schedule:

• for your first dose, you will receive a smaller “step-up” dose of Elrexfio on Day 1 of your treatment
• for your second dose, you will receive a larger “step-up” dose of this medicine, which is usually given on Day 4 of your treatment
• for your third dose, you will receive the first full “treatment” dose of Elrexfio, which is usually given on Day 8 of your treatment
• If your dose is delayed for any reason, you may need to repeat the step-up dosing schedule.
• Before each dose during the step-up dosing schedule, you will receive medicines that help reduce your risk of CRS. Your healthcare provider will decide if you need to receive medicines to help reduce your risk of CRS with future doses.

Neurologic problems. This medicine can cause neurologic problems that can be serious or life-threatening. Tell your healthcare provider or get medical help right away if you develop any signs or symptoms of neurologic problems, including:

• headache
• agitation, trouble staying awake, confusion or disorientation, seeing or hearing things that are not real (hallucinations)
• trouble speaking, thinking, remembering things, paying attention, or understanding things
• problems walking, muscle weakness, shaking (tremors), loss of balance, or muscle spasms
• numbness and tingling (feeling like “pins and needles”)
• burning, throbbing, or stabbing pain
• changes in your handwriting

Elrexfio is available only through the Elrexfio Risk Evaluation and Mitigation Strategy (REMS) due to the risk of CRS and neurologic problems. You will receive an Elrexfio Patient Wallet Card from your healthcare provider. Carry the Elrexfio Patient Wallet Card with you at all times and show it to all of your healthcare providers. The Patient Wallet Card lists symptoms of CRS and neurologic problems. Get medical help right away if you develop any of the symptoms listed on the Patient Wallet Card. You may need to be treated in a hospital.

Your healthcare provider will monitor you for signs and symptoms of CRS and neurologic problems during treatment with Elrexfio, as well as other side effects, and will treat you if needed. Your healthcare provider may temporarily stop or completely stop your treatment with Elrexfio if you develop CRS, neurologic problems, or any other side effects that are severe.

Elrexfio will be given to you by your healthcare provider as an injection under your skin (subcutaneous injection), usually in your stomach-area (abdomen), your thigh, or another area of your body may also be used.

You start Elrexfio with a “step-up dosing schedule”.

You have a dose on Day 1, Day 4, and usually Day 8 and then after that, Elrexio is usually given 1 time each week through to Week 24. Then starting on Week 25, your future doses will usually be given 1 time every 2 weeks.

You will be hospitalized for 48 hours after the first dose and for 24 hours after the second dose of Elrexfio.

Your first dose on Day 1 is a small “step-up” dose. Your second dose is usually given on Day 4, which is a larger “step-up” dose. For your third dose, usually given on Day 8, you will receive the first full “treatment” dose of this medicine.

Usual adult dose Elrexfio:

• step-up dose 1: 12 mg on Day 1,
• step-up dose 2: 32 mg on Day 4,
• first treatment dose: 76 mg on Day 8
• then 76 mg weekly thereafter through week 24
• after 24 weeks 76 mg every two weeks.

Comments

• Dosing after 24 weeks should only occur if patients has achieved a response (partial response or better) and maintained this response for at least 2 months,
• Continue treatment with Eltrexfio until disease progression or unacceptable toxicity.
• Administer pre-treatment medications prior to each dose in the Eltrexfio step-up dosing schedule, which includes step-up dose 1, step-up dose 2, and the first treatment dose as recommended.

Elrexfio is available as

• 76 mg/1.9 mL (40 mg/mL) single-dose vial.
• 44 mg/1.1 mL (40 mg/mL) single-dose vial.

Tell your healthcare provider about all of your medical conditions, including if you:

• have an infection.

Pregnancy

Tell your healthcare provider if you are pregnant, become pregnant, or plan to become pregnant, as Elrexfio may harm your unborn baby.

If you are able to become pregnant, your healthcare provider will ask you to do a pregnancy test before you start treatment with Elrexfio.  You should use effective birth control (contraception) during treatment and for 4 months after your last dose of this medicine.

Breastfeeding

Tell your healthcare provider if you are breastfeeding or plan to breastfeed. It is not known if Elrexfio passes into your breast milk. Do not breastfeed during treatment and for 4 months after your last dose of Elrexfio.

If you miss any appointments, call your healthcare provider as soon as possible to reschedule your appointment. It is important for you to be monitored closely for side effects during treatment with Elrexfio.

Do not drive, operate heavy or potentially dangerous machinery, or do other dangerous activities during treatment with Elrexfio:

• for 48 hours after completing each of the 2 doses that are part of the “step-up dosing schedule” and your first full treatment dose, and
• at any time during treatment with Elrexfio if you develop any new neurologic symptoms such as dizziness, confusion, shaking (tremors), sleepiness, or any other symptom that impairs consciousness, until the symptoms go away.

Common Elrexfio side effects

• decreased white blood cells, red blood cells, and platelets.
• tiredness
• injection site reaction, such as redness, itching, pain, bruising, rash, swelling, tenderness
• diarrhea
• muscle and bone pain
• decreased appetite
• rash
• cough
• nausea
• fever

Serious Elrexfio side effects include:

Infections. Upper respiratory tract infections and pneumonia are common during treatment with this medicine. This medicine can cause bacterial and viral infections that are severe, life-threatening, or that may lead to death.

Your healthcare provider may prescribe medicines for you to help prevent infections and treat you as needed if you develop an infection during treatment with treatment.

Tell your healthcare provider right away if you develop any signs or symptoms of an infection during treatment with this medicine, including these symptoms:

• fever of 100.4 °F (38 °C) or higher
• chills
• cough
• shortness of breath
• chest pain
• sore throat
• pain during urination
• feeling weak or generally unwell.

Decreased white blood cell counts. Decreased white blood cell counts are common during treatment with Elrexfio which can be severe. Fever can happen with low white blood cell counts and may be a sign that you have an infection. Your healthcare provider will treat you as needed.

Liver problems. This medicine can cause increased liver enzymes and bilirubin in your blood. These increases can happen with or without you also having Cytokine Release Syndrome (CRS). Tell your healthcare provider if you develop any of the following signs or symptoms of liver problems:

• tiredness
• loss of appetite
• pain in your right upper stomach area (abdomen)
• dark urine
• yellowing of your skin or the white part of your eyes

Your healthcare provider will check your blood and monitor you for signs and symptoms of these serious side effects before you start and during treatment with Elrexfio. Your healthcare provider may temporarily or completely stop your treatment if you develop certain side effects.

These are not all of the possible side effects from this medicine.

Also see 'Warnings"

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Warnings

Elrexfio may cause serious side effects, including

Cytokine Release Syndrome (CRS). CRS is common during treatment with Elrexfio and can also be serious, life-threatening, or can lead to death. Tell your healthcare provider or get medical help right away if you develop any signs or symptoms of CRS, including:

• fever of 100.4 °F (38 °C) or higher
• trouble breathing
• chills
• dizziness or light-headedness
• fast heartbeat
• headache
• increased liver enzymes in your blood. 

See 'Side Effects' for more information about the signs and symptoms of liver problems.

Due to the risk of CRS, you will receive Elrexfio on a “step-up dosing schedule” and should be hospitalized for 48 hours after the first “step-up” dose and for 24 hours after the second “step-up” dose.

During the step-up dosing schedule:

• for your first dose, you will receive a smaller “step-up” dose of Elrexfio on Day 1 of your treatment
• for your second dose, you will receive a larger “step-up” dose of this medicine, which is usually given on Day 4 of your treatment
• for your third dose, you will receive the first full “treatment” dose of Elrexfio, which is usually given on Day 8 of your treatment
• If your dose is delayed for any reason, you may need to repeat the step-up dosing schedule.
• Before each dose during the step-up dosing schedule, you will receive medicines that help reduce your risk of CRS. Your healthcare provider will decide if you need to receive medicines to help reduce your risk of CRS with future doses.

Neurologic problems. This medicine can cause neurologic problems that can be serious or life-threatening. Tell your healthcare provider or get medical help right away if you develop any signs or symptoms of neurologic problems, including:

• headache
• agitation, trouble staying awake, confusion or disorientation, seeing or hearing things that are not real (hallucinations)
• trouble speaking, thinking, remembering things, paying attention, or understanding things
• problems walking, muscle weakness, shaking (tremors), loss of balance, or muscle spasms
• numbness and tingling (feeling like “pins and needles”)
• burning, throbbing, or stabbing pain
• changes in your handwriting

Elrexfio is available only through the Elrexfio Risk Evaluation and Mitigation Strategy (REMS) due to the risk of CRS and neurologic problems. You will receive an Elrexfio Patient Wallet Card from your healthcare provider. Carry the Elrexfio Patient Wallet Card with you at all times and show it to all of your healthcare providers. The Patient Wallet Card lists symptoms of CRS and neurologic problems. Get medical help right away if you develop any of the symptoms listed on the Patient Wallet Card. You may need to be treated in a hospital.

Your healthcare provider will monitor you for signs and symptoms of CRS and neurologic problems during treatment with Elrexfio, as well as other side effects, and will treat you if needed. Your healthcare provider may temporarily stop or completely stop your treatment with Elrexfio if you develop CRS, neurologic problems, or any other side effects that are severe.

Before Receiving Elrexfio

Tell your healthcare provider about all of your medical conditions, including if you:

• have an infection.

Pregnancy

Tell your healthcare provider if you are pregnant, become pregnant, or plan to become pregnant, as Elrexfio may harm your unborn baby.

If you are able to become pregnant, your healthcare provider will ask you to do a pregnancy test before you start treatment with Elrexfio.  You should use effective birth control (contraception) during treatment and for 4 months after your last dose of this medicine.

Breastfeeding

Tell your healthcare provider if you are breastfeeding or plan to breastfeed. It is not known if Elrexfio passes into your breast milk. Do not breastfeed during treatment and for 4 months after your last dose of Elrexfio.

How Will I Receive Elrexfio?

Elrexfio will be given to you by your healthcare provider as an injection under your skin (subcutaneous injection), usually in your stomach-area (abdomen), your thigh, or another area of your body may also be used.

You start Elrexfio with a “step-up dosing schedule”.

You have a dose on Day 1, Day 4, and usually Day 8 and then after that, Elrexio is usually given 1 time each week through to Week 24. Then starting on Week 25, your future doses will usually be given 1 time every 2 weeks.

You will be hospitalized for 48 hours after the first dose and for 24 hours after the second dose of Elrexfio.

Your first dose on Day 1 is a small “step-up” dose. Your second dose is usually given on Day 4, which is a larger “step-up” dose. For your third dose, usually given on Day 8, you will receive the first full “treatment” dose of this medicine.

Dosing Information

Usual adult dose Elrexfio:

• step-up dose 1: 12 mg on Day 1,
• step-up dose 2: 32 mg on Day 4,
• first treatment dose: 76 mg on Day 8
• then 76 mg weekly thereafter through week 24
• after 24 weeks 76 mg every two weeks.

Comments

• Dosing after 24 weeks should only occur if patients has achieved a response (partial response or better) and maintained this response for at least 2 months,
• Continue treatment with Eltrexfio until disease progression or unacceptable toxicity.
• Administer pre-treatment medications prior to each dose in the Eltrexfio step-up dosing schedule, which includes step-up dose 1, step-up dose 2, and the first treatment dose as recommended.

Elrexfio is available as

• 76 mg/1.9 mL (40 mg/mL) single-dose vial.
• 44 mg/1.1 mL (40 mg/mL) single-dose vial.