Inclusion Criteria:

• Participants who have received at least one dose of cilta-cel in a Company-sponsored clinical study
• Participants who have provided informed consent for this study

Inclusion Criteria:

• Documented multiple myeloma as defined: a) Multiple myeloma diagnosis according to the International Myeloma Working Group (IMWG) diagnostic criteria and b) Measurable disease at screening as defined by any of the following: i) Serum M-protein level greater than or equal to (>=) 0.5 grams per deciliter (g/dL) (central laboratory); ii) Urine M-protein level >= 200 milligram (mg) per 24 hours (central laboratory); iii) Light chain multiple myeloma without measurable M-protein in the serum or the urine: serum immunoglobulin free light chain >= 10 milligram per deciliter (mg/dL) (central laboratory), and abnormal serum immunoglobulin kappa lambda free light chain ratio
• Relapsed or refractory disease as defined by: i) Relapsed disease is defined as an initial response to prior treatment, followed by confirmed progressive disease by IMWG criteria greater than (>) 60 days after cessation of treatment; ii) Refractory disease is defined as less than (<) 25 percent (%) reduction in monoclonal paraprotein (M-protein) or confirmed progressive disease by IMWG criteria during previous treatment or less than or equal to (<=) 60 days after cessation of treatment
• Received at least 1 prior line of antimyeloma therapy including a proteasome inhibitor (PI) and lenalidomide. Participants who have received only 1 prior line of antimyeloma therapy must be considered lenalidomide-refractory (that is, have demonstrated progressive disease by IMWG criteria on or within 60 days of completion of lenalidomide-containing regimen). Participants who have received >=2 prior lines of antimyeloma therapy must be considered lenalidomide exposed
• Documented evidence of progressive disease based on investigator's determination of response by the IMWG criteria on or after their last regimen
• Have an Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2 at screening and immediately prior to the start of administration of study treatment

Exclusion Criteria:

• Contraindications or life-threatening allergies, hypersensitivity, or intolerance to study drug excipients
• Disease is considered refractory to an anti-cluster of differentiation 38 (CD38) monoclonal antibody as defined per IMWG consensus guidelines (progression during treatment or within 60 days of completing therapy with an anti-CD38 monoclonal antibody)
• Received prior pomalidomide therapy
• A maximum cumulative dose of corticosteroids to >=140 milligrams (mg) of prednisone or equivalent within 14-day period before the first dose of study drug
• Known active central nervous system (CNS) involvement or exhibits clinical signs of meningeal involvement of multiple myeloma. If either is suspected, negative whole brain magnetic resonance imaging (MRI) and lumbar cytology are required
• Plasma cell leukemia (per IMWG criteria) at the time of screening, Waldenström's macroglobulinemia, polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS syndrome), or primary amyloid light chain amyloidosis

Inclusion Criteria:

1. Is willing and able to provide written informed consent/assent and to comply with all protocol procedures and assessments required for the study. 2. Is age ≥12 years and >40kg at informed consent/assent. 3. Has had an initial allogeneic HSCT for any indication using any graft source, donor source, conditioning regimen intensity or prophylaxis. 4. Has evidence of myeloid engraftment 5. Has a clinical diagnosis of aGVHD Grades III-IV or Grade II with LGI involvement based on Mount Sinai Acute GVHD International Consortium (MAGIC) grading criteria. 6. Began systemic corticosteroid treatment for aGVHD ≤72 hours prior to the start of study drug dosing AND must receive 2 mg/kg/day methylprednisolone or equivalent on Day 1.

Exclusion Criteria:

1. Evidence of morphological relapsed, progressive, persistent, or untreated malignancy, with the exception of nonmelanoma skin cancer and in situ ductal carcinoma of the breast. 2. An unplanned donor lymphocyte infusion for persistent or recurrent malignancy after HSCT. 3. Evidence of persistent molecular disease requiring treatment that was not specified prior to HSCT. 4. Evidence of cGVHD or overlap syndrome 5. Use of immunosuppressants other than corticosteroids for the treatment of aGVHD. 6. Use of any systemic corticosteroids of >0.5 mg/kg/day methylprednisolone or equivalent for any indication other than aGVHD within 7 days before the onset of aGVHD.

Key Inclusion Criteria:

1. Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1, or 2 2. Confirmed diagnosis of symptomatic multiple myeloma (MM) by International Myeloma Working Group (IMWG) diagnosis criteria 3. Measurable disease, according to the 2016 IMWG response criteria, as defined in the protocol 4. No prior therapy for MM, with the exception of prior emergent or palliative radiation and up to 1 month of single-agent corticosteroids, with washout periods as per the protocol 5. Participants must have evidence of adequate bone marrow reserves and hepatic, renal and cardiac function as defined in the protocol 6. Participants must be age <70 and have adequate hepatic, renal, pulmonary and cardiac function to be considered transplant-eligible. The specific thresholds for adequate organ function are as per institutional guidance.

Key Exclusion Criteria:

1. Receiving any concurrent investigational agent with known or suspected activity against MM, or agents targeting the A proliferation-inducing ligand (APRIL)/ Transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI)/BCMA axis 2. Known central nervous system (CNS) involvement with MM, known or suspected progressive multifocal leukoencephalopathy (PML), a history of neurocognitive conditions, or CNS movement disorder, or history of seizure within 12 months prior to study enrollment 3. Rapidly progressive symptomatic disease, (e.g. progressing renal failure or hypercalcemia not responsive to standard medical interventions), in urgent need of treatment with chemotherapy 4. Diagnosis of non-secretory MM, active plasma cell leukemia, primary light-chain (AL) amyloidosis, Waldenström macroglobulinemia (lymphoplasmacytic lymphoma), or known POEMS syndrome (plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes) Note: Other protocol-defined Inclusion/Exclusion criteria apply

Inclusion Criteria:

• Patient must be able to provide informed consent
• Patients with confirmed diagnosis of multiple myeloma
• Able to swallow and retain oral medication
• All ethnic groups are eligible

Exclusion Criteria:

• Non-English speaking person
• Patients undergoing haploidentical allogeneic hematopoietic stem cell transplant
• Known allergies, hypersensitivity, or intolerance to any of the study medications, excipients, or similar compounds
• Any medical complications or conditions that would, in the investigator's judgement, interfere with full participation in the study
• On therapeutic dose of aspirin (doses greater than 81 mg) within 7 days prior to the start of the study