On April 29, 2026 Pfizer Inc. (NYSE: PFE) reported positive topline results from the Phase 3 MagnetisMM-5 study evaluating ELREXFIO (elranatamab) as monotherapy in adults with relapsed or refractory multiple myeloma (RRMM) who received at least one prior line of treatment. The study demonstrated a statistically significant and clinically meaningful improvement in the primary endpoint of progression‑free survival (PFS), as assessed by blinded independent central review (BICR), versus standard-of-care daratumumab plus pomalidomide and dexamethasone (DPd). The safety and tolerability of ELREXFIO was consistent with its known safety profile.
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The PFS results exceeded the pre-specified interim analysis target hazard ratio for efficacy, with most ELREXFIO-treated patients remaining progression-free. The trial remains ongoing to assess overall survival, a key secondary endpoint, which was not yet mature at the time of this interim analysis. These data will be discussed with global health authorities, and detailed results from MagnetisMM-5 will be submitted for presentation at a future medical congress.
Multiple myeloma is an aggressive and currently incurable blood cancer that affects plasma cells made in the bone marrow:
It is the second most common type of blood cancer worldwide, with over 36,000 new cases each year in the United States and over 187,000 globally.1,2,3
Despite treatment advances, most patients relapse and develop relapsed or refractory disease, often requiring multiple lines of therapy, with approximately 40% not surviving beyond five years.2,4
Multiple myeloma can significantly impact quality of life, with immune suppression increasing susceptibility to infection, and symptoms such as fatigue, bone pain, and psychological distress making everyday activities more difficult.5-7
"Effective intervention earlier in the course of disease represents a critical opportunity to improve outcomes for people living with multiple myeloma," said Jeff Legos, Chief Oncology Officer, Pfizer. "ELREXFIO has already helped address a significant unmet need in heavily pre‑treated patients, delivering deep, durable, and clinically meaningful responses. The MagnetisMM-5 results reinforce our confidence in ELREXFIO’s potential to benefit patients earlier in their treatment journey and support our comprehensive strategy to evaluate ELREXFIO both as monotherapy and as part of combination approaches across multiple lines of therapy."
ELREXFIO is approved in more than 35 countries worldwide, including in the United States where it received accelerated approval for use in adults with RRMM who have received at least four prior lines of therapy, and in the European Union where it was granted conditional marketing authorization for adults with RRMM who have received at least three prior therapies and have demonstrated disease progression on the last therapy.
MagnetisMM-5 is part of a comprehensive development program in double-class exposed MM patients. The program includes the fully recruited Phase 3 MagnetisMM-32 study, which is designed to evaluate ELREXFIO in patients who have previously received daratumumab as part of standard-of-care front-line MM treatment.
About Multiple Myeloma
Multiple myeloma is an aggressive and currently incurable blood cancer that affects plasma cells made in the bone marrow. Healthy plasma cells make antibodies that help the body fight infection.6 While disease trajectory varies for each person, relapses are nearly inevitable.9 The goal of therapy for people with relapsing or refractory multiple myeloma is to achieve disease control with acceptable toxicity and improved quality of life.10
About MagnetisMM-5
MagnetisMM-5 is an open-label, multicenter, randomized Phase 3 study to evaluate the efficacy and safety of ELREXFIO versus standard-of-care daratumumab plus oral pomalidomide and dexamethasone in patients with RRMM. The study enrolled 497 patients across 26 countries who have received at least one line of previous treatment, including lenalidomide and a proteasome inhibitor (PI). Participants received subcutaneous ELREXFIO as two step-up priming doses followed by a weekly 76 mg injection, with frequency adjusted to every two weeks after 24 weeks if a partial response was achieved for more than two months, and again to every four weeks for all patients after 48 weeks on treatment. The primary endpoint is progression-free survival (PFS), as assessed by blinded independent central review (BICR). A key secondary endpoint is overall survival.
Pfizer continues to evaluate ELREXFIO both as a monotherapy and as a combination regimen as part of the MagnetisMM clinical trial program.
About ELREXFIO (elranatamab)
ELREXFIO is a subcutaneously delivered B-cell maturation antigen (BCMA)-cluster of differentiation CD3-directed bispecific antibody immunotherapy that binds to BCMA on myeloma cells and CD3 on T cells, activating the T cells to kill myeloma cells.
U.S. Important Safety Information and Indication
ELREXFIO may cause side effects that are serious, life-threatening, or can lead to death, including cytokine release syndrome (CRS) and neurologic problems. CRS is common during treatment with ELREXFIO.
Tell your healthcare provider or get medical help right away if you develop any signs or symptoms of CRS or neurologic problems, 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
agitation, trouble staying awake, confusion or disorientation, or 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
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 of ELREXFIO.
For your first dose, you will receive a smaller "step-up" dose of ELREXFIO on day 1
For your second dose, you will receive a larger "step-up" dose of ELREXFIO, which is usually given on day 4 of treatment
For your third dose, you will receive the first "treatment" dose of ELREXFIO, which is usually given on day 8
If your dose of ELREXFIO is delayed for any reason, you may need to repeat step-up dosing. Before each dose of ELREXFIO during the step-up dosing schedule, you will receive medicines to 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.
ELREXFIO is available only through the ELREXFIO Risk Evaluation and Mitigation Strategy (REMS) Program 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 ELREXFIO Patient Wallet Card lists signs and symptoms of CRS and neurologic problems. Get medical help right away if you develop any of the signs and symptoms listed on the ELREXFIO Patient Wallet Card. You may need to be treated in a hospital.
Before taking ELREXFIO, tell your healthcare provider about all of your medical conditions, including if you:
have an infection
are pregnant or plan to become pregnant. ELREXFIO may harm your unborn baby. Females who are able to become pregnant should do a pregnancy test before starting treatment with ELREXFIO and should use effective birth control during treatment and for four months after your last dose of ELREXFIO. Tell your healthcare provider right away if you become pregnant or think that you may be pregnant during treatment with ELREXFIO
are breastfeeding or plan to breastfeed. It is not known if ELREXFIO passes into your breast milk. Do not breastfeed during treatment and for four months after your last dose of ELREXFIO
Tell your healthcare provider about all of the medications you take, including prescription and over-the-counter medications, vitamins, and herbal supplements.
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 of ELREXFIO 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
Infections: Upper respiratory tract infection and pneumonia are common during treatment with ELREXFIO. ELREXFIO can cause bacterial and viral infections that are severe, life-threatening, or that may lead to death.
Your healthcare provider may prescribe medications for you to help prevent infections and treat you as needed if you develop an infection during treatment with ELREXFIO
Tell your healthcare provider right away if you develop any signs or symptoms of an infection during treatment with ELREXFIO, including: fever of 100.4°F (38°C) or higher, chills, cough, shortness of breath, chest pain, sore throat, pain during urination, or feeling weak or generally unwell
People with active infections should not start ELREXFIO
Decreased white blood cell counts: Decreased white blood cell counts are common during treatment with ELREXFIO and can also be severe. A fever can occur 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: ELREXFIO can cause increased liver enzymes and bilirubin in your blood. These increases can happen with or without you also having CRS. Tell your healthcare provider if you develop any of the following signs or symptoms of a liver problem, including:
tiredness
loss of appetite
pain in your right upper stomach-area
dark urine
yellowing of your skin or the white part of your eyes
The most common side effects of ELREXFIO include:
tiredness
injection site reaction, such as redness, itching, pain, bruising, rash, swelling, and tenderness
diarrhea
muscle and bone pain
decreased appetite
rash
cough
nausea
fever
The most common severe abnormal lab test results with ELREXFIO include decreased white blood cells, red blood cells, and platelets.
Your healthcare provider may temporarily or permanently stop ELREXFIO if you have any of the side effects listed and they are severe. These are not all of the possible side effects of ELREXFIO.
Call your healthcare provider for medical advice about side effects. You may report side effects to the U.S. Food and Drug Administration (FDA) at 1-800-FDA-1088.
What is ELREXFIO?
ELREXFIO is a prescription medication used to treat adults with multiple myeloma who:
have already received at least 4 treatment regimens, including a proteasome inhibitor, an immunomodulatory agent, and an anti-CD38 monoclonal antibody, to treat their multiple myeloma, and
their cancer has come back or did not respond to prior treatment
ELREXFIO was approved based on patient responses and durability of response. There are ongoing studies to confirm its clinical benefit. It is not known if ELREXFIO is safe and effective in children.
Please read full Prescribing Information, including BOXED WARNING, for ELREXFIO.
(Press release, Pfizer, APR 29, 2026, View Source [SID1234664918])