Elotuzumab, Daratumumab, Iberdomide, and Dexamethasone for the Treatment of Relapsed Multiple Myeloma

Inclusion Criteria: * Age ≥ 18 years at the time of signing the informed consent form (ICF). * Diagnosis of relapsed multiple myeloma with ≤ 3 prior lines of therapy including treatment with proteasome inhibitors (i.e., ixazomib, carfilzomib, bortezomib), immunomodulatory imide drugs (i.e., lenalidomide, pomalidomide), and anti-CD38 drugs (i.e., daratumumab, isatuximab). Patients are required to have received a proteasome inhibitor, immunomodulatory imide drug, or combination of the two drug classes during first-line treatment. * Note: Prior treatment with iberdomide is not allowed. Patients should not be refractory simultaneously to all other drugs in the combination. * Measurable disease. * Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1 or 2. * Hemoglobin ≥ 8.0 g/dL (obtained ≤14 days prior to registration). * Absolute neutrophil count (ANC) ≥ 1000/m\^3 (obtained ≤14 days prior to registration). * Platelet count ≥ 50,000/mm\^3. Note: It is not permissible to transfuse subjects to achieve minimum platelet counts (obtained ≤14 days prior to registration). * Total bilirubin ≤ 1.5 x upper limit of normal (ULN) (≤ 3 x ULN for patients with Gilbert's syndrome) (obtained ≤14 days prior to registration). * Alanine aminotransferase (ALT) and aspartate transaminase (AST) ≤ 2 x ULN and alkaline phosphatase ≤ 1.5 x ULN (obtained ≤14 days prior to registration). * Calculated creatinine clearance ≥ 30 ml/min using the Cockcroft-Gault (obtained ≤14 days prior t…