Cellectis’ Licensed Partner, Allogene Therapeutics,  Announces Removal of FDA Clinical Hold on their Clinical Trials

• Allogene reported that Chromosomal Abnormality Was Not the Result of TALEN® Gene Editing or Allogene’s Manufacturing Process
• Allogene to Initiate a Phase 2 Pivotal Clinical Trial of ALLO-501A in Relapsed/Refractory Large B-cell Lymphoma Mid-year 2022 Pending FDA Discussion

January 10, 2022 – New York (N.Y.) – Cellectis (Euronext Growth: ALCLS - Nasdaq: CLLS), a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies, today stated that its licensed partner, Allogene Therapeutics, Inc. (Nasdad: ALLO) announced that the U.S. Food and Drug Administration (FDA) has lifted the hold on its clinical trials.

The FDA had placed a clinical hold on all five of Allogene’s clinical trials on October 7, 2021 following a report of a chromosomal abnormality detected in ALLO-501A CAR+ T-cells from a single patient enrolled in Allogene’s ALPHA2 study. Allogene reported today that the investigations concluded that the chromosomal abnormality was unrelated to TALEN® gene editing or Allogene’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 natural T cell or B cell maturation process.

“We are very pleased that our licensed partner Allogene is now able to resume its clinical trials, bringing us one step closer to delivering these innovative therapies to patients with unmet medical needs”, said Dr. André Choulika, CEO of Cellectis. “TALEN® gene editing technologies were not involved in the findings leading to the clinical hold. More than 170 patients with relapsed or refractory malignancies have been administered TALEN®-edited allogeneic CAR-T cell product candidates with a favorable safety profile, making it the largest and most robust disclosed clinical dataset of any gene editing technology in the world.”

Allogene also announced that following the lift of the clinical holds and pending final discussions with the FDA, Allogene intends to initiate a Phase 2 pivotal trial of ALLO-501A in relapsed/refractory large B-cell lymphoma mid-year 2022.

Allogene’s allogeneic CAR-T programs utilize Cellectis’ technologies. ALLO-501 and ALLO-501A are anti-CD19 products being jointly developed under a collaboration agreement between Servier and Allogene based on an exclusive license granted by Cellectis to Servier. Servier grants to Allogene exclusive rights to ALLO-501 and ALLO-501A in the U.S. while Servier retains exclusive rights for all other countries.

Allogene has an exclusive license to Cellectis’ technologies for ALLO-715, ALLO-605 (both directed at BCMA) and ALLO-316 (directed at CD70) and holds development and commercial rights for these investigational product candidates.