General Key Inclusion Criteria:
- Eastern Cooperative Oncology Group (ECOG) performance status ≤1
- Participants must have measurable disease as defined in the protocol according to IMWG consensus criteria
- Adequate creatinine clearance, hematologic function and hepatic function, as defined in protocol
- Life expectancy of at least 6 months
Cohort Specific Inclusion Criteria:
For cohorts 1-6, each participant must have RRMM with progression following at least 3 lines of therapy, or at least 2 lines of therapy and either prior exposure to at least 1 anti-CD38 antibody, 1 immunomodulatory imide drug (IMiD) and 1 Proteasome Inhibitor (PI), or double-refractory to 1 PI and 1 IMiD, or the combination of 1 PI and 1 IMiD Cohort 1: Prior treatment with daratumumab is allowed if previously tolerated, as described in the protocol Cohort 2: Prior treatment with carfilzomib is allowed if previously tolerated at the approved full dose, as described in the protocol Cohort 3: Prior treatment with lenalidomide is allowed if previously tolerated at the approved full dose, as described in the protocol Cohort 4: Prior treatment with bortezomib is allowed if previously tolerated at the approved full dose, as described in the protocol Cohort 5: Prior treatment with pomalidomide is allowed if previously tolerated at the approved full dose, as described in the protocol Cohort 6: Prior treatment with isatuximab is allowed if previously tolerated, as described in the protocol
Cohort 7 and 8:
- For participants without measurable disease by biochemical parameters [serum or urine M-protein, or serum involved Free Light Chain (FLC)], presence of at least 1 soft tissue plasmacytoma with a single diameter of ≥2 cm
- RRMM with progressive disease and received at least 3 lines of therapy including exposure to at least 1 anti-CD38 antibody, 1 IMiD, and 1 PI or triple-class refractory disease (anti-CD38 antibody, IMiD, PI) Cohort 9: Progressive RRMM in participants with triple-class refractory disease (anti-CD38 antibody, IMiD, PI) after at least 3 lines of therapy Cohort 10: Progressive RRMM after at least 3 lines of therapy including exposure to at least 1 anti-CD38 antibody, 1 IMiD, and 1 PI
General Key Exclusion Criteria:
- Diagnosis of plasma cell leukemia, primary light-chain amyloidosis (excluding myeloma associated amyloidosis), Waldenström macroglobulinemia (lymphoplasmacytic lymphoma), or POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal protein, and Skin changes)
- Participants with known MM brain lesions or meningeal involvement
- Treatment with any systemic anti-myeloma therapy within 5 half-lives or within 21 days prior to first administration of study drug regimen, whichever is shorter
- History of allogeneic and autologous stem cell transplantation, as described in the protocol
- Unless stated otherwise in a specific sub-protocol, prior treatment with a T cell-based immunotherapy directed against B-Cell Maturation Antigen (BCMA) bispecific antibodies and Bispecific T-cell Engagers (BiTEs), and BCMA Chimeric Antigen Receptor (CAR) T cells (Note: BCMA antibody-drug conjugates are not excluded)
- History of progressive multifocal leukoencephalopathy, neurodegenerative condition or Central Nervous System (CNS) movement disorder or participants with a history of seizure within 12 months prior to study enrollment are excluded
- Live or attenuated vaccination within 28 days prior to first study drug regimen administration with a vector that has replicative potential
- Cardiac ejection fraction <40% by Echocardiogram (Echo) or Multigated Acquisition (MUGA) scan
Cohort Specific Exclusion Criteria:
Cohort 2: Dose expansion: Prior treatment with a BCMA-directed CAR T-cell therapy will not be exclusionary if completed at least 12 weeks prior to first study treatment Cohort 3: Known malabsorption syndrome or pre-existing gastrointestinal (GI) condition that may impair absorption of lenalidomide; delivery of lenalidomide via nasogastric tube or gastrostomy tube is not allowed Cohort 4: Peripheral neuropathy grade ≥2 Cohort 5: Known malabsorption syndrome or pre-existing GI conditions that may impair absorption of pomalidomide; delivery of pomalidomide via nasogastric tube or gastrostomy tube is not allowed
Cohort 7:
- Prior treatment with anti-Lymphocyte Activation Gene 3 (LAG-3) agents. Prior exposure to vaccine therapies or other immune checkpoint modulating therapies such as anti-Programmed cell Death Protein 1 (PD-1) antibodies is permitted, as described in the protocol
- Ongoing or recent (within 2 years) evidence of an autoimmune disease that has required systemic treatment with immunosuppressive agents, as described in the protocol
- Prior solid organ transplant
- History of grade ≥3 immune-mediated adverse events (with the exclusion of endocrinopathies that are fully controlled by hormone replacement) from prior checkpoint inhibitor therapies
Cohort 8:
- Prior treatment with anti-PD-1 or anti-PD-L1 agents. Prior exposure to vaccine therapies or other immune checkpoint modulating therapies such as anti-Cytotoxic T Lymphocyte-Associated Antigen 4 (CTLA-4) antibodies is permitted, as described in the protocol
- Encephalitis or meningitis in the year prior to enrollment
- History of interstitial lung disease (eg, idiopathic pulmonary fibrosis or organizing pneumonia), of active, noninfectious pneumonitis that required immune-suppressive doses of glucocorticoids to assist with management, or of pneumonitis within the last 5 years. A history of radiation pneumonitis in the radiation field is permitted as long as pneumonitis resolved ≥6 months prior to enrollment
- Ongoing or recent (within 2 years) evidence of an autoimmune disease that has required systemic treatment with immunosuppressive agents, as described in the protocol.
- Prior solid organ transplant
- History of grade ≥3 immune-mediated adverse events (with the exclusion of endocrinopathies that are fully controlled by hormone replacement) from prior checkpoint inhibitor therapies
Cohort 9:
- Abnormal QT interval corrected by Fridericia's formula (QTcF), as described in the protocol
- Use of concomitant medications that are known to prolong the QT/QTcF interval including Class Ia and Class III antiarrhythmics at the time of informed consent
- Ongoing use or anticipated use of food or drugs that are known strong/moderate cytochrome P450 (CYP)3A4 inhibitors, or strong CYP3A inducers within 14 days prior to first dose of nirogacestat
- Known malabsorption syndrome or existing gastrointestinal GI condition that may impair absorption of nirogacestat; delivery of nirogacestat via nasogastric tube or gastrostomy tube is not allowed
Cohort 10:
- Known or suspected active Epstein-Barr Virus (EBV) infection
- Known history of Hemophagocytic Lymphohistiocytosis/Macrophage Activation Syndrome (HLH/MAS)
- Prior treatment with cevostamab or another agent with the same target [Fragment crystallizable Receptor-like 5 (FcRH5)]
Dose finding portion: Prior treatment with any BCMA-directed immunotherapy will not be exclusionary, as described in the protocol Dose expansion portion: Prior treatment with any T cell-engaging bispecific antibody directed against BCMA will be exclusionary, as described in the protocol
NOTE: Other protocol defined inclusion/exclusion criteria apply