The purpose of the study is to evaluate the effect of Elranatamab therapy after cilta-cel measuring how long a patient with high risk relapsed myeloma lives without the myeloma getting worse(progressing), also known as progression-free survival (PFS). Patients with clinical high-risk myeloma, defined as having history of myeloma that has grown outside of the bones or having high risk mutations in the myeloma cells, benefit less from cilta-cel compared to myeloma patients without these characteristics.

Inclusion Criteria:

• Understand and voluntarily sign an informed consent form.
• Have received commercial cilta-cel within 3-6 months for relapsed refractory myeloma and have high risk cytogenetics by IMW (del17p, or t(4;14) or t(14;16) or history of EMD, and must not have evidence of progressive disease by IMWG criteria(Appendix B) following CAR-T cell therapy.
• Have received >2 prior treatment regimens including an immunomodulatory drug, a proteasome inhibitor and a CD38 monoclonal antibody.
• Able to adhere to the study visit schedule and other protocol requirements.
• Patients must have available clonoseq ID prior to enrollment to track MRD status.
• Eastern Cooperative Group (ECOG) Performance Status of 0 or 1.
• Serum bilirubin levels ≤1.5 times the upper limit of the normal range for the laboratory (ULN), unless related to Gilbert syndrome.
• Serum AST or serum ALT levels ≤2 x ULN.
• Must have adequate bone marrow function.

Exclusion Criteria:

• Ongoing active infection defined as an infection that is worsening despite therapy and causing symptoms or requiring intravenous antibiotic treatment.
• Ongoing CRS or ICANS of any grade.
• Active plasma cell leukemia.
• Patients with CNS involvement, including meningeal involvement.
• Patients with history of Guillain-Barre syndrome.
• Uncontrolled medical problems such as diabetes mellitus, congestive heart failure, coronary artery disease, hypertension, unstable angina, arrhythmias), pulmonary, hepatic and renal diseases unless renal insufficiency is felt to be secondary to multiple myeloma, which in the opinion of the treating physician pose an unacceptable risk to the patient.
• Pregnant or lactating females.
• Concurrent use of other anti-cancer agents or treatments.
• Known seropositive for or active viral infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV). Patients who are seropositive because of hepatitis B virus vaccine are eligible. Note: patients with hepatitis C previously treated with curative intent are considered eligible.
• Patients with renal failure requiring dialysis.