Mezigdomide, Carfilzomib, and Dexamethasone for the Treatment of Relapsed or Refractory Multiple Myeloma in Patients With Extramedullary Disease

Inclusion Criteria: * Age ≥ 18 years of age * Have an Eastern Cooperative Oncology Group (ECOG) performance status of ≤ 2 * RRMM patients with one or more prior lines of therapy with at least one ES or PS lesion that is accessible to a biopsy. Accessibility will be assessed by the MM tumor board * Measurable disease meeting at least one of the following: * Serum M-protein ≥1 g/dL * Urine M-protein ≥200 mg/24 h * Serum FLC assay: involved FLC level ≥10 mg/dL provided serum FLC ratio is abnormal * Up to 10 patients without measurable disease can be enrolled but screening imaging and/or bone marrow biopsy have to confirm RRMM. Follow-up response assessment will be performed with imaging using RECIST 1.1 and Deauville Criteria and bone marrow biopsies * Absolute neutrophil count: ≥ 1 x 10\^9/L * Platelets: ≥ 75 x 10\^9/L * Total bilirubin: ≤ 1.5 x upper limit of normal (ULN) * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamic pyruvic transaminase \[SGPT\]): ≤ 3 x ULN * Renal function: Estimated creatinine clearance ≥ 30 mL/min (Cockroft-Gault) * Adequate cardiac pump function with a left ventricular ejection fraction of ≥ 40% * Women of child-bearing potential must agree to use adequate contraceptive methods (e.g., hormonal or barrier method of birth control; abstinence) prior to study entry and for at least 28 days after the last dose of mezigdomide or 6 months after the last dose of carfi…