Allogene Therapeutics, Inc. announced that the U.S. Food and Drug Administration (FDA) has removed the clinical hold on all of the company's AlloCAR T clinical trials. The company previously announced on October 7, 2021 that the FDA had placed a hold on all five of the company's AlloCAR T clinical trials based on a report of a chromosomal abnormality detected post-AlloCAR T administration in a single patient treated with ALLO-501A in the ALPHA2 study. Investigations concluded that the chromosomal abnormality was unrelated to TALEN® gene editing or the company's manufacturing process and had no clinical significance.

The abnormality was not detected in any manufactured AlloCAR T product or in any other patient treated with the same ALLO-501A lot. The abnormality occurred in the patient after the cell product was administered. It involved regions of the T cell receptor and immunoglobulin genes known to undergo rearrangement as part of the T cell or B cell maturation process.

The company will be working with clinical trial investigators to resume study activities across AlloCAR T development programs as quickly as possible. Pending final discussions with the FDA, the company also plans to initiate its pivotal Phase 2 trial of ALLO-501A in relapsed/refractory Large B Cell Lymphoma (LBCL) mid-year 2022.