Cellectis Receives Orphan Drug Designation for UCART22, its Allogeneic CAR T Product for Patients with Acute Lymphoblastic Leukemia

New York, NY - June 4, 2024 - Cellectis (the "Company") (Euronext Growth: ALCLS - NASDAQ: CLLS), a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies, announced today that the European Commission (EC) has granted an Orphan Drug Designation (ODD) to its product candidate UCART22, for the treatment of Acute Lymphoblastic Leukemia (ALL).

UCART22 is an allogeneic CAR T-cell product candidate targeting CD22 and evaluated in BALLI-01, a Phase 1/2 open-label dose-escalation and dose-expansion study, designed to evaluate the safety, expansion, persistence and clinical activity of UCART22 in patients with relapse/refractory ALL.

ALL represents 12% of all leukemia cases, progresses rapidly, and is typically fatal within weeks or months if left untreated[1]. In 2024, the 10-year prevalence is estimated at 1.9 in 100,000 persons in the European Union (EU). Based on the preliminary clinical data generated with UCART22 in heavily pretreated patients who were relapsed or refractory to approved medicinal products, the European Medicines Agency (EMA) considered that the significant benefit of UCART22 has been demonstrated.

"Patients with relapsed/refractory ALL have limited, if any, treatment options, especially for those who have failed prior CD19 directed CAR T-cell therapy and allogeneic stem cell transplant" said Mark Frattini, M.D., Ph.D., Chief Medical Officer at Cellectis. "The Orphan Drug Designation for UCART22 marks an important step towards developing allogeneic CAR T products that would be readily available for all patients."

The last clinical data presented by Cellectis at the American Society of Hematology in December 2023 were encouraging and suggested that UCART22-P2 (fully manufactured in-house) is more potent with a preliminary response rate of 67% at Dose Level 2, compared to a 50% response rate at Dose Level 3 with UCART22-P1 (manufactured by an external CDMO). Cellectis expects to provide updates on the progress of BALLI-01 by year-end 2024.

The Orphan Drug Designation in the EU is granted by the EC based on a positive opinion issued by the EMA Committee for Orphan Medicinal Products. Medicines intended for the treatment, diagnosis or prevention of seriously debilitating or life-threatening conditions that affect fewer than five in 10,000 people in the EU are eligible for the designation. The Orphan Drug Designation allows companies certain regulatory, financial, and commercial incentives to develop medicines for rare diseases where there are no satisfactory treatment options.

[1] (Dong et al., 2020)