A Study of Venetoclax Plus Lenalidomide and Dexamethasone for the Treatment of Newly Diagnosed t(11;14)-Positive Multiple Myeloma in Subjects Who Are Ineligible for High-Dose Therapy

* Must have documented, confirmed active multiple myeloma (MM) with greater than or equal to 10% clonal bone marrow plasma cells or biopsy-proven bone or extramedullary plasmacytoma and any one or more of the following myeloma-defining events: * Evidence of end organ damage attributed to the underlying plasma cell proliferative disorder and satisfying at least one of the protocol specified laboratory criteria for calcium elevation, renal failure, anemia, or lytic bone lesions; OR * One or more of the biomarkers of malignancy as described in the protocol. * Must have MM positive for the t(11;14) translocation, as determined by methods described in the protocol. * Must have measurable disease defined by at least one of the following criteria: * Serum M-protein ≥ 1.0 g/dL (immunoglobulin \[Ig\]G myeloma) or greater than or equal to 0.5 g/dL (IgA, IgM, IgD, or IgE myeloma); * Urine M-protein greater than or equal to 200 mg/24 hours; * Serum free light chain (FLC) greater than or equal to 10 mg/dL (100 mg/L) provided serum FLC ratio is abnormal. * Newly diagnosed and not considered a candidate for high-dose therapy and hematopoietic stem cell transplantation (HSCT) * Must have Eastern Cooperative Oncology Group performance status less than or equal to 2.

* Has a co-existing condition as specified in the protocol. * Has history of other active malignancies, including myelodysplastic syndromes (MDS) within the past 3 years with specific exceptions detailed in the protocol. * Has been treated with or received any of the following: * Prior or current systemic therapy or hematopoietic stem cell transplantation (HSCT) for MM (a short course of treatment with corticosteroids equivalent to dexamethasone 40 mg/day for a maximum of 4 days is allowed before treatment); use of systemic strong or moderate inhibitor or inducer of cytochrome P450(CYP)3A within 7 days before the first dose of study drug. * Radiation therapy within 2 weeks of dosing * Plasmapheresis within 4 weeks of dosing * Immunization with live vaccine within 8 weeks of dosing * Has a contraindication or inability to comply with antithrombotic prophylaxis.