Common Side Effects of Elrexfio
Elrexfio (elranatamab-bcmm), a bispecific antibody for relapsed or refractory multiple myeloma, causes side effects mainly from cytokine release syndrome (CRS) and neurologic issues. Most frequent ones (occurring in >20% of patients) include CRS (57%), fatigue (47%), musculoskeletal pain (44%), injection site reactions (41%), nausea (39%), and upper respiratory tract infection (37%).[1][2]
Serious Side Effects and Warnings
CRS happens in nearly 60% of patients, mostly low-grade (grade 1-2) within 1-2 days of the first dose, but can be severe (grade 3) or fatal. Symptoms: fever, low blood pressure, hypoxia. Neurologic toxicity like immune effector cell-associated neurotoxicity syndrome (ICANS) affects 17%, with symptoms such as confusion, seizures, or speech issues. Other risks: infections (60%, including fatal ones), cytopenias (low blood counts leading to anemia, neutropenia), and rare spinal cord compression from myeloma growth.[1][3]
How Side Effects Are Managed
CRS and ICANS require monitoring; premedication with steroids, acetaminophen, and antihistamines reduces risk. Step-up dosing starts low to minimize reactions. Hospitalization may be needed for severe cases. Infections prompt antibiotics or antivirals; blood count checks guide transfusions or growth factors.[1][2]
Side Effects by Frequency
| Frequency | Examples |
|-----------|----------|
| ≥50% | CRS, fatigue |
| 30-50% | Pain, injection reactions, nausea, infections |
| 10-30% | Diarrhea, constipation, headache, dyspnea, rash |
| <10% | ICANS, oral issues, edema, liver enzyme rise[1][3] |
Differences from Similar Drugs
Compared to teclistamab (Tecvayli), another bispecific, Elrexfio has similar CRS rates but slightly higher fatigue and fewer hypogammaglobulinemia cases. Both need CRS mitigation, but Elrexfio's subcutaneous dosing may ease injection reactions long-term.[2][4]
Patient Experiences and Long-Term Risks
Patients report quick CRS resolution but lingering fatigue and neuropathy. Long-term: increased infection risk due to B-cell depletion persists. Liver toxicity or secondary cancers are rare but monitored.[1][3]
[1]: Elrexfio Prescribing Information (Pfizer)
[2]: FDA Approval Summary for Elrexfio
[3]: MagnetisMM-3 Trial Data (NEJM)
[4]: DrugPatentWatch.com - Elrexfio Patent Status