Polyfunctionality correlates with a patient's remission lasting over 18 months with the CAR T cell  therapy

IRVINE, Calif., Aug. 7, 2024 -- PeproMene Bio, Inc., a clinical-stage biotech company developing novel therapies for cancers and immune disorders, today announced that City of Hope-developed BAFF-R CAR T, known as PMB-CT01, demonstrated better polyfunctionality than CD19 CAR T cells, which are used in current Food and Drug Administration-approved CAR T cell therapies, according to a correlative study published in Blood Advances.

Researchers used a single-cell platform, which found that PMB-CT01 CAR T cells, had more polyfunctionality, which is T cells' ability to perform several functions at the same time, than CD 19 CAR T cells. PMB-CT01 cells also produced more stimulatory cytokines, which can spur the immune system, and effector cytokines, which can directly kill cancer cells.

Using the City of Hope-developed assay, researchers tested a BAFF-R CAR T cell product from a 57-year-old man with relapsed mantle cell lymphoma. The patient had not achieved remission with prior CD19 CAR T cell therapies. After receiving one infusion in City of Hope's Phase 1 trial using PMB-CT01 and experiencing minimal side effects, the man has been in complete remission over 18 months and continues to have undetectable cancer by sensitive molecular tests for minimal residual disease.

The study reported robust indicators of polyfunctionality, which correlated with successful CAR T cell expansion post-infusion and the patient's ongoing remission. Researchers plan to use the assay to test CAR T cell products from five other patients in the trial, all of whom have experienced similar remissions to PMB-CT01.

"We developed BAFFR-CAR T therapy as another treatment option for a significant number of patients with lymphomas and leukemias who relapse after receiving commercial CD19 CAR T cell therapy, and our results so far represent the ideal maximal efficacy with minimal toxicity," said Larry W. Kwak, M.D., Ph.D., vice president and deputy director of City of Hope's Comprehensive Cancer Center and PeproMene's scientific founder and compensated chair of its Scientific Advisory Board. Kwak has an equity interest in PeproMene. "We have developed a robust and reliable polyfunctional assay for CAR T cell products, with the potential to predict patient outcomes and accelerate the development of effective CAR T cell therapies."

Elizabeth Budde, M.D., Ph.D., the trial's principal investigator, an associate professor of hematology and hematopoietic cell transplantation and the executive medical director for the Immune Effector Cell Therapy Program at City of Hope, presented initial trial results at the American Society of Hematology's conference in December 2023.

"It's exciting to say that five patients with  non-Hodgkin lymphoma and one with B-cell acute lymphoblastic leukemia have been treated with PMB-CT01 and 100% have demonstrated durable responses," Dr. Budde said. "Many of the trial patients relapsed had after CD19 CAR T therapy and/or were CD19 negative. PMB-CT01 could present a viable option for other patients who also face this dilemma."

"This assay can be applied to current and future clinical trials to guide the development of PMB-CT01. PeproMene remains committed to the ongoing scientific and clinical development of this potentially promising new cell therapy" said Hazel Cheng Ph.D., COO of PeproMene Bio.

About PMB-CT01

PMB-CT01 is a first-in-class, BAFF-R-targeted, autologous CAR T cell therapy.  BAFF-R (B- Cell Activating Factor Receptor), a member of the tumor necrosis factor (TNF) receptor superfamily, is the main receptor for BAFF and is expressed almost exclusively on B cells. Since BAFF-R signaling promotes normal B-cell proliferation and appears to be required for B-cell survival, tumor cells are unlikely to escape therapy via loss of the BAFF-R antigen. This unique characteristic makes BAFFR CAR T therapy a highly promising option for treating B-cell malignancies. The BAFFR CAR was constructed using anti-BAFF-R single-chain fragment variable (scFv) antibodies and second-generation signaling domains CD3ζ and 4-1BB. Our research has demonstrated that BAFFR-CAR T cells effectively kill human lymphomas and leukemias both in vitro and in animal models. PeproMene Bio has licensed the intellectual property of PMB-CT01 from City of Hope.

About PeproMene Bio

PeproMene Bio, Inc. is a clinical-stage biotech company in Irvine, California developing novel therapies to treat cancers and immune disorders. PeproMene's lead candidate, PMB-CT01 (BAFFR-CAR T cells) is currently being investigated to treat relapsed and refractory B-cell acute lymphoblastic leukemia (B-ALL; NCT04690595) and B-cell non-Hodgkin lymphoma (B-NHL; NCT05370430) in phase 1 clinical trials. PeproMene Bio is also developing BAFFR Bispecific T Cell Engager and BAFFR-CAR NK cells.

Contact: John Fry, john.fry@pepromenebio.com

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