1st Patient Dosed with Cellectis’ Allogeneic UCART22 in Relapsed/Refractory B-cell Acute Lymphoblastic Leukemia

BALLI-01 Clinical Trial Commenced at MD Anderson Cancer Center

December 2, 2019 – New York (N.Y.) – Cellectis (Euronext Growth: ALCLS - Nasdaq: CLLS), a clinical-stage biopharmaceutical company focused on developing immunotherapies based on gene-edited allogeneic CAR T-cells (UCART), announced today that the first patient enrolled in the dose escalation Phase 1 clinical study for its UCART22 product candidate has been dosed at The University of Texas MD Anderson Cancer Center. This clinical study, BALLI-01, will evaluate the safety, expansion, persistence and clinical activity of UCART22, a product candidate composed of engineered T-cells expressing anti-CD22 chimeric antigen receptors, in patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL).

UCART22 targets CD22, which is a B-cell restricted surface antigen expressed in normal B-lineage cells, as well as in blast cells from B-ALL and other B-cell malignancies.

“By targeting the CD22 antigen, we aim at offering a therapeutic solution to patients living with B-ALL, including those patients that have relapsed or did not respond to CD19-directed therapy, such as CAR-T or bispecific antibody treatments. UCART22 is an allogeneic product candidate that can be dosed in all eligible patients even if they underwent prior autologous or allogeneic CAR-T therapies,” said Dr. André Choulika, Chairman and CEO, Cellectis. “With the recent announcement of our UCARTCS1 first dosing, this milestone shows our momentum at Cellectis as we continue moving forward our portfolio of proprietary product candidates into clinical development. We have high hopes that UCART22 will address an unmet medical need for patients with B-ALL, with the potential to expand into other indications for B-cell malignancies.”

The clinical trial is led by Dr. Nitin Jain, MD, Associate Professor, Department of Leukemia, Division of Cancer Medicine at The University of Texas MD Anderson Cancer Center (Houston, TX) in collaboration with Dr. Richard Larson, MD, Director of the Hematologic Malignancies Clinical Research Program at the University of Chicago Medicine (Chicago, IL) and with Dr. Gail Roboz, MD, Director, Clinical and Translational Leukemia Programs, Professor of Medicine, Weill Cornell Medical College The New York Presbyterian Hospital (New York, NY).

About UCART22

UCART22 is one of Cellectis’ wholly owned, allogeneic, off-the-shelf gene-edited T-cell product candidates, designed for the treatment of relapsed and refractory B-cell acute lymphoblastic leukemia (R/R B-ALL). Like CD19, CD22 is a cell surface antigen expressed from the pre-B-cell stage of development through mature B-cells. CD22 expression occurs in more than 90% of patients with B-ALL.

About B-cell Acute Lymphoblastic Leukemia (B-ALL)

B-cell acute lymphoblastic leukemia (B-ALL) is a hematologic disease characterized by the proliferation of immature lymphoid cells in the bone marrow, peripheral blood and other organs. The increase and accumulation of blast cells in the bone marrow results in suppression of the normal production of blood cell and blood plasma components, and can therefore cause anemia, thrombocytopenia, neutropenia and risk of infection. Acute lymphoblastic leukemia (ALL) can start either with early B-cells or T-cells at different stages of maturity, however, approximately 85% of ALL cases involve precursor B-cells (B-ALL).