A Clinical Trial of Four Medicines (Elranatamab Plus Carfilzomib and Dexamethasone or Maplirpacept) in People With Relapsed Refractory Multiple Myeloma

Inclusion Criteria:

* Prior diagnosis of multiple myeloma as defined by IMWG criteria.
* Measurable disease based on IMWG criteria as defined by at least 1 of the following:

  * Serum M-protein ≥0.5 g/dL.
  * Urinary M-protein excretion ≥200 mg/24 hours.
  * Serum immunoglobulin FLC ≥10 mg/dL (≥100 mg/L) AND abnormal serum immunoglobulin kappa to lambda FLC ratio (\<0.26 or \>1.65).
* Part 1: Received at least 1 but not more than 3 prior lines of therapy for multiple myeloma (induction therapy followed by stem cell transplant and consolidation/maintenance therapy will be considered as 1 line of therapy).
* Part 2: Received at least 3 prior lines of therapy for multiple myeloma who are refractory to at least one IMiD, one PI and one anti-CD38 antibody.
* ECOG performance status 0-1.
* Resolved acute effects of any prior therapy to baseline severity or CTCAE Grade ≤1.
* Not pregnant or breastfeeding and willing to use contraception.

Exclusion Criteria:

* Plasma cell leukemia, Smouldering MM, Waldenströms macroglobulinemia, Amyloidosis, POEMS Syndrome, Primary refractory MM
* Impaired cardiovascular function or clinically significant cardiovascular diseases.
* Participants with any active, uncontrolled bacterial, fungal, or viral infection.
* Stem cell transplant within 12 weeks prior to enrollment, or active graft versus host disease.
* Any other active malignancy within 3 years prior to enrollment, except for adequately treated basal cell or squamous cell skin cancer, or carcinoma in situ.
* Part 1: Previous treatment with a BCMA-directed therapy.
* Part 2: Previous treatment with any anti-BCMA directed therapy, with the exception of CAR-T. Previous treatment with a CD47-SIRP alpha-directed therapy.
* Part 1: Prior treatment with carfilzomib
* Live attenuated vaccine within 4 weeks of the first dose of study intervention.
* Administration with an investigational product (e.g. drug or vaccine) concurrent with study intervention or within 30 days preceding the first dose of study intervention used in this study.
* Any of the following within 3 months of enrollment: erosive esophagitis, treatment resistant peptic ulcer, infectious or inflammatory bowel disease, pulmonary embolism or uncontrolled thromboembolic event.
* Intolerance to or participants who have had a severe (Grade ≥3) allergic or anaphylactic reaction to antibodies or therapeutic proteins