Testing Teclistamab (TECVAYLI) in Combination With Iberdomide for Relapsed or Refractory Multiple Myeloma

Inclusion Criteria: * Patients must have histologically or cytologically confirmed multiple myeloma (MM), as defined in the International Myeloma Working Group (IMWG) criteria * If patients have undergone autologous stem cell transplant (SCT), day 0 of SCT must be \> 100 days to be eligible for the study * Patients must have had disease progression after ≥ 4 prior lines of anti-myeloma treatments including one proteasome inhibitor (e.g., bortezomib, carfilzomib, ixazomib), one immunomodulatory imide drug (ImiD) (e.g., thalidomide, lenalidomide, pomalidomide \[POM\]), and one anti-CD38 monoclonal antibody (e.g., daratumumab, isatuximab) * Patients must have measurable disease, defined as: * Serum M-protein ≥ 0.5 g/dL (≥ 5 g/L) * Urine M-protein ≥ 200 mg/24 h * Serum free light chain (FLC) assay: "involved" FLC level ≥ 10 mg/dL (≥ 100 mg/L) and an abnormal serum free light chain ratio (\< 0.26 or \> 1.65) * Note: Patients with non-secretory disease will be allowed to participate * Age ≥ 18 years * Because no dosing or adverse event data are currently available on the use of iberdomide in combination with teclistamab in patients \< 18 years of age, children are excluded from this study * Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2 (Karnofsky ≥ 60) * Hemoglobin ≥ 7.0 g/dL (≤ 28 days prior to registration) (Without growth factor support, blood transfusion, or platelet stimulating agents for the past 7 days, excluding erythropoietin) * Absolute neu…