Safety and Efficacy of ALLO-715 BCMA Allogenic CAR T Cells in in Adults With Relapsed or Refractory Multiple Myeloma (UNIVERSAL)

Inclusion Criteria: * Documented diagnosis of relapsed/refractory multiple myeloma (MM) with measurable disease (serum, urine, or free light chain \[FLC\]) per International Myeloma Working Group (IMWG) criteria * At least 3 prior lines of MM therapy, including a proteasome inhibitor, immunomodulatory agent, and anti-CD38 antibody (unless contraindicated), and refractory to the last treatment line. * Eastern Cooperative Oncology Group (ECOG) 0 or 1 * Absence of donor (product)-specific anti-HLA antibodies * Adequate hematologic, renal, hepatic, pulmonary, and cardiac function Exclusion Criteria: * Current or history of Central Nervous System (CNS) involvement of myeloma or plasma cell leukemia * Clinically significant CNS disorder * Current or history of thyroid disorder * Autologous stem cell transplant within the last 6 weeks, or any allogeneic stem cell transplant * Prior treatment with anti-BCMA therapy, any gene therapy, any genetically modified cell therapy, or adoptive T cell therapy * History of HIV infection or acute or chronic active hepatitis B or C infection * Patients unwilling to participate in an extended safety monitoring period Additional Exclusion Criteria for Nirogacestat plus ALLO-715 Cohorts * Inability to swallow tablets * Subject has known malabsorption syndrome or preexisting gastrointestinal conditions that may impair absorption of nirogacestat * Use of strong/moderate CYP3A4 inhibitors, and strong CYP3A4 inducers within 14 days before starting nirogacestat. * Use of concomitant medications that are known to prolong the QT/QTcF interval