A Study to Learn About the Effects of the Combination of Elranatamab (PF-06863135), Daratumumab, and Lenalidomide Compared With Daratumumab, Lenalidomide, and Dexamethasone in Patients With Newly Diagnosed Multiple Myeloma Who Are Not Candidates for Transplant (MagnetisMM-6)

Inclusion Criteria: Diagnosis of multiple myeloma (MM) as defined by IMWG criteria (Rajkumar et al., 2014) 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; Involved FLC ≥10 mg/dL (≥100 mg/L) AND abnormal serum immunoglobulin kappa to lambda FLC ratio (<0.26 or >1.65). Part 1: Participants with relapsed/refractory multiple myeloma (RRMM) who have received 1-2 prior lines of therapy including at least one immunomodulatory drug and one proteasome inhibitor: or participants with newly-diagnosed multiple myeloma (NDMM) that are transplant-ineligible as defined by age ≥65 years or transplant-ineligible as defined by age <65 years with comorbidities impacting the possibility of transplant. Part 2: participants with newly-diagnosed multiple myeloma that are transplant-ineligible as defined by age ≥65 years or transplant-ineligible as defined by age <65 years with comorbidities impacting the possibility of transplant ECOG performance status ≤2. Not pregnant and willing to use contraception For participants with RRMM: Resolved acute effects of any prior therapy to baseline severity or CTCAE Grade ≤1. Exclusion Criteria: Smoldering Multiple Myeloma. Monoclonal gammopathy of undetermined significance. Waldenströms Macroglobulinemia Plasma cell leukemia. Active, uncontrolled bacterial, fungal, or viral infection, including (but not limited to) COVID-19/SARS-CoV-2, HBV, HCV, and known HIV or AIDS-related illness. Any other active malignancy within 3 years prior to enrollment, except for adequately treated basal cell or squamous cell skin cancer, carcinoma in situ, or Stage 0/1 with minimal risk of recurrence per investigator. For participants with RRMM: Previous treatment with a BCMA-directed therapy or anti-CD38-directed therapy within 6 months preceding the first dose of study intervention in this study. Stem cell transplant ≤3 months prior to first dose of study intervention or active GVHD. For participants with NDMM: Previous systemic treatment for MM except for a short course of corticosteroids (ie, up to 4 days of 40 mg dexamethasone or equivalent before the first dose of study intervention). Live attenuated vaccine administered within 4 weeks of the first dose of study intervention. Administration of investigational product (eg, drug or vaccine) concurrent with study intervention or within 30 days (or as determined by the local requirement) preceding the first dose of study intervention used in this study.