Mezigdomide (CC-92480) Post Idecabtagene Vicleucel in Treating Patients With Relapsed Multiple Myeloma

Inclusion Criteria:

• Documented informed consent of the participant and/or legally authorizedrepresentative.

• Assent, when appropriate, will be obtained per institutional guidelines

• Age: >= 18 years

• Eastern Cooperative Oncology Group (ECOG) =< 2

• Diagnosis of multiple myeloma

• Subject must have received at least 4 prior lines of therapy, including animmunomodulatory agent, a proteasome inhibitor, and an anti-CD38 antibody

• Receipt of commercially available idecabtagene vicleucel (Abecma) according to FDAapproved US Prescribing Information. Note: Patients who received non-conformingAbecma who were originally prescribed Abecma according to the FDA approved label maybe considered for inclusion per the investigators discretion. Subject must bebetween day 30 and day 90 post receipt of idecabtagene vicleucel

• Subject must have experienced at least a stable disease in response to idecabtagenevicleucel

• Fully recovered from the acute toxic effects (except alopecia) to =< grade 1 toprior anti-cancer therapy, including idecabtagene vicleucel

• Absolute neutrophil count (ANC) >= 1,500/mm^3 without the use of filgrastim in theprevious 3 days (To be performed within 14 days prior to day 1 of protocol therapyunless otherwise stated)

• Two repeat tests are allowed. If the repeat test satisfies criteria, theparticipant may enroll provided all other criteria are met

• Platelets >= 75,000/mm^3 without platelet transfusion in the previous 3 days. (To beperformed within 14 days prior to day 1 of protocol therapy unless otherwise stated)

• Two repeat tests are allowed. If the repeat test satisfies criteria, theparticipant may enroll provided all other criteria are met

• Total bilirubin =< 1.5 X upper limit of normal (ULN) (unless has known Gilbert'sdisease) (To be performed within 14 days prior to day 1 of protocol therapy unlessotherwise stated).

• Two repeat tests are allowed. If the repeat test satisfies criteria, theparticipant may enroll provided all other criteria are met

• Aspartate aminotransferase (AST) =< 3 x ULN (To be performed within 14 days prior today 1 of protocol therapy unless otherwise stated).

• Two repeat tests are allowed. If the repeat test satisfies criteria, theparticipant may enroll provided all other criteria are met

• Alanine transaminase (ALT) =< 3 x ULN (To be performed within 14 days prior to day 1of protocol therapy unless otherwise stated).

• Two repeat tests are allowed. If the repeat test satisfies criteria, theparticipant may enroll provided all other criteria are met

• Alkaline phosphatase =< 5 x ULN (To be performed within 14 days prior to day 1 ofprotocol therapy unless otherwise stated)

• Creatinine clearance of >= 50 mL/min per 24 hour urine test or the Cockcroft-Gaultformula (To be performed within 14 days prior to day 1 of protocol therapy unlessotherwise stated).

• Two repeat tests are allowed. If the repeat test satisfies criteria, theparticipant may enroll provided all other criteria are met

• Oxygen saturation > 92% on room air (To be performed within 14 days prior to day 1of protocol therapy unless otherwise stated)

• Women of childbearing potential (WOCBP): negative urine or serum pregnancy test. Ifthe urine test is positive or cannot be confirmed as negative, a serum pregnancytest will be required (To be performed within 14 days prior to day 1 of protocoltherapy unless otherwise stated)

• Agreement by females of childbearing potential and males to follow the guidelines ofthe mezigdomide (CC-92480) pregnancy prevention plan

Exclusion Criteria:

• Prior exposure to mezigdomide (CC-92480)

• Current or planned use of other therapies other than mezigdomide (CC-92480)

• Patients who are currently receiving or likely to require systemic immunosuppressivetherapy. Physiologic replacement of steroids (=< 5.0 mg/day prednisone orequivalent) is allowed

• Concomitant use of CYP3A4/5 inhibitors and inducers

• Concomitant use of proton pump inhibitors

• Evidence of relapse as evaluated by the treating physician or study investigator

• Active central nervous system involvement

• Ongoing toxicities associated with cytokine release syndrome (CRS) or Immuneeffector cell-associated neurotoxicity syndrome (ICANS) from CAR T cell therapy

• History of allergic reactions attributed to compounds of similar chemical orbiologic composition to study agent

• Coronavirus disease 2019 (COVID-19) positive, as assessed by a polymerase chainreaction (PCR) test or active uncontrolled infections (defined as active antibioticuse within 7 days of starting the investigational drug)

• If human immunodeficiency virus (HIV) positive: CD4+ T cell count < 200

• Females only: Pregnant or breastfeeding

• Any other condition that would, in the Investigator's judgment, contraindicate thepatient's participation in the clinical study due to safety concerns with clinicalstudy procedures

• Prospective participants who, in the opinion of the investigator, may not be able tocomply with all study procedures (including compliance issues related tofeasibility/logistics)