Gracell Biotechnologies Inc., a global clinical-stage biopharmaceutical company dedicated to developing highly efficacious and affordable cell therapies for the treatment of cancer, announced the early results of a first-in-human clinical study of GC502, an allogeneic CD19/CD7 dual-directed chimeric antigen receptor (CAR) T cell therapy for the treatment of relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL). Gracell will share the data in a poster presentation at the American Association for Cancer Research (AACR) Annual Meeting 2022 on April 12.
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GC502 leverages the novel dual-directed CAR design of Gracell‘s proprietary TruUCAR platform, designed to generate high-quality allogeneic CAR-T cell therapies that can be administered “off-the-shelf” at lower cost and with faster patient’s access. TruUCAR-enabled GC502 utilizes the dual-directed CAR design with one CAR targeting CD19 on malignant cells and a second CAR targeting CD7 to suppress host-versus-graft rejection. An enhancer molecule is embedded in the basic construct of TruUCAR to enhance proliferation of TruUCAR T cells.
“We are very excited to present our data on GC502 at this year’s AACR annual meeting. CD19 is a validated target in the treatment of r/r B-ALL,” said Dr. Martina Sersch, Chief Medical Officer of Gracell. “As an allogeneic, off-the-shelf CAR-T therapy, GC502 has the potential to provide patients who may not be eligible for autologous CAR-T therapy with hope to achieve a deep response. The early results show the potential of GC502 and warrant further evaluation in the ongoing clinical investigator-initiated-trial (IIT). Being the second product candidate from our allogeneic TruUCAR platform, GC502 further validates TruUCAR’s platform approach and potential wide applicability.”
Between September 2021 and January 2022, four r/r B-ALL patients were enrolled and treated in an open-label, non-randomized, prospective IIT study in China in two different dose levels and with two different formulations. Patients were heavily pretreated, and all had previously received either autologous or donor derived CD19 or CD19/CD22 targeted CAR-T therapy. As of the January 28, 2022 data cutoff date, all four patients had received a single dose of GC502, including one patient at dose level 1 (DL1) 1.0×107 cells/kg and three patients at dose level 2 (DL2) 1.5×107 cells/kg. Patients received a Flu/Cy based lymphodepletion regimen prior to treatment with GC502.
As highlighted in the AACR poster, three out of four patients achieved minimal residual disease negative complete response or complete response with incomplete count recovery (MRD- CR/CRi), and one patient achieved a partial response at month one and subsequently received allogeneic hematopoietic stem-cell transplantation (allo-HSCT) on day 39.
Cytokine release syndrome (CRS) presented as Grade 2 and Grade 3 with no Grade 4 or 5 events. No immune effector cell-associated neurotoxicity syndrome (ICANS) or acute graft-versus-host disease (aGvHD) were observed.