This phase I trial will begin to understand the safety and effectiveness of a new form of immunotherapy for the treatment of patients with multiple myeloma who have not responded or got worse using previous treatmentA Phase 1 Dose Escalation and Cohort Expansion Study of the Safety and Efficacy of Anti-BCMA Allogeneic CRISPR-Cas9-Engineered T Cells (CTX120) in Subjects With Relapsed or Refractory Multiple Myeloma

Exclusion

1. Prior allogeneic stem cell transplant (SCT).
2. Less than 60 days from autologous SCT at time of screening and with unresolved serious complications.
3. Prior treatment with any gene therapy or genetically modified cell therapy, including CAR T cells or natural killer cells, or BCMA-directed therapy.
4. Evidence of direct central nervous system (CNS) involvement by multiple myeloma.
5. History or presence of clinically relevant CNS pathology such as a seizure disorder, cerebrovascular ischemia/hemorrhage, dementia, cerebellar disease, any autoimmune disease with CNS involvement.
6. Unstable angina, clinically significant arrhythmia, or myocardial infarction within 6 months of enrollment.
7. Active HIV, hepatitis B virus or hepatitis C virus infection.
8. Previous or concurrent malignancy, except basal cell or squamous cell skin carcinoma, adequately resected and in situ carcinoma of cervix, or a previous malignancy that was completely resected and has been in remission for ≥5 years.
9. Use of systemic anti-tumor therapy or investigational agent within 14 days prior to enrollment.
10. Primary immunodeficiency disorder or active autoimmune disease requiring steroids and/or other immunosuppressive therapy.
11. Women who are pregnant or breastfeeding.