A Trial to Learn How Well Linvoseltamab Works Compared to the Combination of Elotuzumab, Pomalidomide and Dexamethasone for Adult Participants With Relapsed/Refractory Multiple Myeloma

• Linvoseltamab (Drug), also known as REGN5458, Lynozyfic™: REGN5458 will be administered by intravenous (IV) infusion
• Elotuzumab (Drug), also known as Empliciti: Elotuzumab will be administered by IV infusion
• Pomalidomide (Drug), also known as Pomalyst: Pomalidomide capsules will be administered by mouth (PO)
• Dexamethasone (Drug), also known as Decadron: Dexamethasone tablets/capsules will be administered PO and/or by IV infusion

Primary outcomes

• Progression Free Survival (PFS) per International Myeloma Working Group (IMWG) response criteria determined by Independent Review Committee (IRC) in CD38 antibody exposed participants [Up to approximatively 5 years]

Secondary outcomes

• PFS per IMWG response criteria determined by IRC in all participants [Up to approximatively 5 years]
• Objective Response (OR) of Complete Response (CR) or better per IMWG response criteria as determined by IRC in CD38 antibody exposed participants [Up to approximatively 5 years]
• OR of CR or better per IMWG response criteria as determined by IRC in all participants [Up to approximatively 5 years]
• Overall Survival (OS) in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• OS in all participants [Up to approximatively 5 years]
• Incidence of minimal residual disease (MRD) negative status in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Incidence of MRD negative status in all participants [Up to approximatively 5 years]
• Mean change in the worst pain score measured by Brief Pain Inventory-Short Form (BPI-SF) Item 3 in participants previously exposed to CD38 antibodies [Baseline to week 12]: The BPI-SF is a validated, self-administered questionnaire designed to measure a participant's perceived level of pain. The BPI-SF Item 3 uses a numeric rating scale to assess pain severity and pain interference in the past 24 hours. The numeric rating scale ranges from 0 (no pain) to 10 (worst imaginable pain), where higher scores indicate greater intensity of pain.
• Mean change in the worst pain score measured by BPI-SF Item 3 in all participants [Baseline to week 12]: The BPI-SF is a validated, self-administered questionnaire designed to measure a participant's perceived level of pain. The BPI-SF Item 3 uses a numeric rating scale to assess pain severity and pain interference in the past 24 hours. The numeric rating scale ranges from 0 (no pain) to 10 (worst imaginable pain), where higher scores indicate greater intensity of pain.
• Incidence of treatment emergent adverse events (TEAEs) in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Incidence TEAEs in all participants [Up to approximatively 5 years]
• Severity of TEAEs in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Severity of TEAEs in all participants [Up to approximatively 5 years]
• Incidence of adverse events of special interest (AESI) in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Incidence of AESI in all participants [Up to approximatively 5 years]
• Severity of AESI in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Severity AESI in all participants [Up to approximatively 5 years]
• Incidence of Serious Adverse Events (SAE) in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Incidence of SAE in all participants [Up to approximatively 5 years]
• Severity of SAE in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Severity of SAE in all participants [Up to approximatively 5 years]
• PFS per IMWG response criteria as determined by the investigator in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• PFS per IMWG response criteria as determined by the investigator in all participants [Up to approximatively 5 years]
• OR of Partial Response (PR) or better per IMWG response criteria as determined by the IRC in CD38 antibody exposed participants [Up to approximatively 5 years]
• OR of PR or better per IMWG response criteria as determined by the IRC in all participants [Up to approximatively 5 years]
• OR of Very Good Partial Response (VGPR) or better per IMWG response criteria as determined by IRC in CD38 antibody exposed participants [Up to approximatively 5 years]
• OR of VGPR or better per IMWG response criteria as determined by IRC in all participants [Up to approximatively 5 years]
• OR of PR or better per IMWG response criteria as determined by the investigator in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• OR of PR or better per IMWG response criteria as determined by the investigator in all participants [Up to approximatively 5 years]
• OR of VGPR or better per IMWG response criteria as determined by the investigator in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• OR of VGPR or better per IMWG response criteria as determined by the investigator in all participants [Up to approximatively 5 years]
• OR of CR or better per IMWG response criteria as determined by the investigator in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• OR of CR or better per IMWG response criteria as determined by the investigator in all participants [Up to approximatively 5 years]
• Duration of Response (DoR) as per IMWG response criteria as determined by the investigator in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• DoR as per IMWG response criteria as determined by the investigator in all participants [Up to approximatively 5 years]
• DoR as per IMWG response criteria as determined by the IRC in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• DoR as per IMWG response criteria as determined by the IRC in all participants [Up to approximatively 5 years]
• Duration of MRD negative status in the bone marrow in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Duration of MRD negative status in the bone marrow in all participants [Up to approximatively 5 years]
• Time from randomization to objective response (≥PR) as per IMWG response criteria as determined by the investigator in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Time from randomization to objective response (≥PR) as per IMWG response criteria as determined by the investigator in all participants [Up to approximatively 5 years]
• Time from randomization to objective response (≥PR) as per IMWG response criteria as determined by the IRC in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Time from randomization to objective response (≥PR) as per IMWG response criteria as determined by the IRC in all participants [Up to approximatively 5 years]
• Concentration of linvoseltamab in the serum over time in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Concentration of linvoseltamab in the serum over time in all participants [Up to approximatively 5 years]
• Incidence of antidrug antibodies (ADAs) in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Incidence of ADAs in all participants [Up to approximatively 5 years]
• Titer of ADAs in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Titer of ADAs in all participants [Up to approximatively 5 years]
• Incidence of neutralizing antibodies (Nabs) to linvoseltamab over time in participants previously exposed to CD38 antibodies [Up to approximatively 5 years]
• Incidence of Nabs to linvoseltamab over time in all participants [Up to approximatively 5 years]
• Proportion of Pain Responders in participants previously exposed to CD38 antibodies [At week 12]: Defined by at least a 2-point reduction from baseline in the BPI-SF Item 3 without an increase in analgesic use using the modified Analgesic Quantification Algorithm (AQA).
• Proportion of Pain Responders in all participants [At week 12]: Defined by at least a 2-point reduction from baseline in the BPI-SF Item 3 without an increase in analgesic use using the modified Analgesic Quantification Algorithm (AQA).
• Change in patient-reported global health status/quality of life (QoL), per European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) in participants previously exposed to CD38 antibodies [Baseline to week 12]: The EORTC-QLQ-C30 is a 30-item subject self-report questionnaire composed of both multi-item and single scales, including global health status/quality of life, functional Scales (physical, role, emotional, cognitive, and social), symptom scales (fatigue, nausea and vomiting, and pain), and 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). Participants rate items on a 4-point scale, with 1 as "not at all" and 4 as "very much."
• Change in patient-reported QoL, per EORTC QLQ-C30 in all participants [Baseline to week 12]: The EORTC-QLQ-C30 is a 30-item subject self-report questionnaire composed of both multi-item and single scales, including global health status/quality of life, functional Scales (physical, role, emotional, cognitive, and social), symptom scales (fatigue, nausea and vomiting, and pain), and 6 single items (dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties). Participants rate items on a 4-point scale, with 1 as "not at all" and 4 as "very much."
• Change in patient reported disease symptoms per EORTC Quality of Life Questionnaire-Multiple Myeloma (MM) module 20 [QLQ-MY20]) in participants previously exposed to CD38 antibodies [Baseline to week 12]: The EORTC QLQ-MY20 is a self -administered instrument to assess QoL in persons with MM. This 20-item questionnaire measures the following domains: symptom scales, including disease symptoms (6 items) and symptoms related to side effects of treatment (10 items); function scale and future perspective (3 items); and body image (1 item). A high score represents a high level of symptoms or problems.
• Change in patient reported disease symptoms per EORTC QLQ-MY20 in all participants [Baseline to week 12]: The EORTC QLQ-MY20 is a self -administered instrument to assess QoL in persons with MM. This 20-item questionnaire measures the following domains: symptom scales, including disease symptoms (6 items) and symptoms related to side effects of treatment (10 items); function scale and future perspective (3 items); and body image (1 item). A high score represents a high level of symptoms or problems.
• Patient-Reported Outcomes in Patient Global Impression of Symptom Severity (PGIS) in participants previously exposed to CD38 antibodies [Baseline to week 12]: The PGIS is a single 1-item questionnaire designed to assess participant's overall impression of disease severity at a given point in time by using a 4-point Likert scale that ranges from (1) = "none (no symptoms)" to (4) = "severe". The global anchor, PGIS will be used for interpretation of EORTC QLQ-C30, EORTC QLQ-MY20, and BPI-SF.
• Patient-Reported Outcomes in PGIS in all participants [Baseline to week 12]: The PGIS is a single 1-item questionnaire designed to assess participant's overall impression of disease severity at a given point in time by using a 4-point Likert scale that ranges from (1) = "none (no symptoms)" to (4) = "severe". The global anchor, PGIS will be used for interpretation of EORTC QLQ-C30, EORTC QLQ-MY20, and BPI-SF.
• Patient-Reported Outcomes in Patient Global Impression of Change (PGIC) in participants previously exposed to CD38 antibodies [Baseline to week 12]: The PGIC is a single-item questionnaire designed to assess the participant's overall sense of whether there has been a change since starting treatment as rated on a 5-point Likert scale anchored by (1) "much better" to (5) "much worse", with (4) = "no change". The global anchor, PGIC will be used for interpretation of EORTC QLQ-C30, EORTC QLQ-MY20, and BPI-SF.
• Patient-Reported Outcomes in PGIC in all participants [Baseline to week 12]: The PGIC is a single-item questionnaire designed to assess the participant's overall sense of whether there has been a change since starting treatment as rated on a 5-point Likert scale anchored by (1) "much better" to (5) "much worse", with (4) = "no change". The global anchor, PGIC will be used for interpretation of EORTC QLQ-C30, EORTC QLQ-MY20, and BPI-SF.
• Change in patient-reported general health status per EuroQoL-5 Dimension-5 Level Scale [EQ-5D-5L]) in participants previously exposed to CD38 antibodies [Baseline to week 12]: The EQ-5D-5L consists of EQ-5D descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems and extreme problems.
• Change in patient-reported general health status per EQ-5D-5L in all participants [Baseline to week 12]: The EQ-5D-5L consists of EQ-5D descriptive system comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems and extreme problems.

Sex: All, ages: 18 Years to any

Key Inclusion Criteria:

1. Age 18 years or older (or legal adult age in the country) at the time of the screening visit.
2. Eastern Cooperative Oncology Group (ECOG) performance status ≤1. Patients with ECOG 2 solely due to local symptoms of myeloma (eg. pain) may be allowed after discussion with the Medical Monitor.
3. Received at least 1 and no more than 4 prior lines of anti-neoplastic MM therapies, including lenalidomide and a proteasome inhibitor and demonstrated disease progression on or after the last therapy as defined by the 2016 IMWG criteria. Participants who have received only 1 line of prior line of antimyeloma therapy must be lenalidomide refractory, as described in the protocol.

   Note: Participants in Israel also must have previously received a CD38 antibody. Participants in the EU and the UK must have previously received 2 to 4 prior lines of therapy, including a CD38 antibody.
4. Patients must have measurable disease for response assessment as per the 2016 IMWG response assessment criteria, as described in the protocol
5. Adequate hematologic function and hepatic function within 7 days of randomization, as well as adequate renal and cardiac function and corrected calcium
6. Life expectancy of at least 6 months

Key Exclusion Criteria:

1. Diagnosis of plasma cell leukemia, amyloidosis, Waldenström macroglobulinemia, or POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes).
2. Prior treatment with elotuzumab and/or pomalidomide
3. Participants with known MM brain lesions or meningeal involvement
4. Treatment with any systemic anti-cancer therapy within 5 half-lives or within 28 days before first administration of study drug, whichever is shorter
5. History of allogeneic stem cell transplantation within 6 months, or autologous stem cell transplantation within 12 weeks of the start of study treatment. Participants who have received an allogeneic transplant must be off all immunosuppressive medications for 6 weeks without signs of graft-versus-host disease. Steroids at doses equivalent to suppletion doses may be acceptable.
6. Prior treatment with B-cell maturation antigen (BCMA) directed immunotherapies Note: BCMA antibody-drug conjugates are allowed.
7. History of progressive multifocal leukoencephalopathy (PML), known or suspected PML, or history of a neurocognitive condition or central nervous system (CNS) movement disorder (Parkinson's disease or Parkinsonism).
8. Any infection requiring hospitalization or treatment with IV anti-infectives within 2 weeks of first administration of study drug
9. Uncontrolled infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV); or another uncontrolled infection, as defined in the protocol 10 Cardiac ejection fraction <40%.

NOTE: Other protocol defined inclusion/exclusion criteria apply

59 more sites not listed.

• Clinical Trial Management, Study director, Regeneron Pharmaceuticals