EXUMA Biotech Announces Phase 1 Results for its Autologous HER2 Directed, Tumor Metabolism Regulated (TMR) CAR-T Product at ASCO GI 2025

No dose-limiting toxicities, severe adverse events, or on-target off-tumor toxicities across all dose cohorts

Deep and durable response observed in gastroesophageal cancer

EXUMA now advancing its clinically de-risked solid tumor & hematologic CARs with in vivo GCAR^™ platform and SCL mRNA technology

WEST PALM BEACH, Fla., Jan. 23, 2025 /PRNewswire/ -- EXUMA Biotech, Corp., a clinical-stage biotechnology company discovering and developing cell and gene immunotherapies for solid and hematological malignancies, is presenting clinical data from a completed Phase 1 trial evaluating a novel autologous HER2-targeted CAR-T therapy. The data presented today at the ASCO Gastrointestinal Cancers Symposium, highlights promising efficacy and safety for autologous engineered human T cells that target cancer via a proprietary chimeric antigen receptor (CAR) designed to selectively target HER2 in the tumor microenvironment (TME).

The single center, investigator-initiated, dose escalation trial enrolled 12 patients with HER2-positive Stage IV solid tumor malignancies, including three gastric, one esophageal, four colorectal, and four breast cancers. Patients received a single dose of CAR-T cells (3E5, 1E6, or 1E7 CAR+ cells/kg) from a peripheral blood draw-derived 12-day manufacturing process (17 days to product release) following lymphodepletion with cyclophosphamide and fludarabine. No manufacturing failures occurred.

Key Findings:

• Safety: No dose limiting toxicities or investigational-product related serious adverse events. No adverse events leading to study discontinuation. One patient experienced Grade 2 cytokine release syndrome (CRS), which resolved. No ICANs or any other CNS toxicities occurred. No on-target, off-tumor toxicity (OTOTT) was detected with longitudinal clinical and laboratory assessments.
• Efficacy: A deep PR (100% reduction in SLD) was observed in a gastroesophageal cancer patient that was ongoing at 36 weeks of follow-up. Cohort 3's 12-month survival rate was 80%, compared to 45.5% for all three dose cohorts combined.

Wendy Li, MD Chief Medical Officer of EXUMA Biotech, remarked, "There continues to be a need for treatments with the potential to safely elicit frequent deep and durable responses in HER2 positive gastroesophageal cancer patients through different mechanisms of action. We administered the maximum feasible dose, which delivered clear anti-tumor activity in patients without OTOTT or dose limiting toxicities. Our team is now focused on patients with HER2 positive gastroesophageal malignancies, particularly in Asia, where the incidence of gastroesophageal cancers contributes significantly to morbidity and mortality." 

Abstract Title: Clinical results of a phase 1 trial evaluating a HER2 directed CAR-T product selective for the tumor microenvironment (TME) in patients with GI and other solid tumor malignancies
Abstract ID: 449
Poster #: F14

About CCT303-406
CCT303-406 is EXUMA Biotech's TMR autologous CAR-T product candidate targeting HER2, which has completed an investigator-initiated clinical trial in patients with metastatic HER2+ solid tumors. HER2 overexpression is a hallmark of several tumors, including those originating from breast, stomach, bladder, and colon. Patients relapse or become unresponsive to antibody-based regimens targeting HER2 in early lines of treatment yet may still retain overexpression of HER2. CCT303-406 has clinically shown to be a promising option for gastroesophageal patients providing T cell-mediated antitumor activity via targeting HER2. Differentiated from other HER2 CAR-T therapies, CCT303-406 incorporates EXUMA's TMR targeting technology, focusing CAR-T activity to the TME, thereby reducing the risk of on-target, off-tumor toxicity.

GCAR^™ and SCL Update
EXUMA plans to complete non-human primate (NHP) studies in support of its 1^st in vivo CAR-T product, GCAR^™ and SCL mRNA LNP technology in 1H25. Studies will assess vector selectivity (tropism), biodistribution, pharmacokinetics, pharmacodynamics and safety as well as the influence of SCL mRNA administration on GCAR^™ cellular PK. Results from these studies will inform regulatory discussions for IND enabling activities in the US for its 1^st GCAR^™ product for clinical investigation.

"We are pleased with these data that support our decade-long vision to expand the safety and efficacy of CAR-T into solid tumors," stated Gregory Frost, Ph.D. Chairman and CEO of EXUMA Biotech. "Towards the second and equally important dimension of this vision, we look forward to advancing these and other CARs into clinical investigation with our in vivo GCAR^™ platform, enabled by EXUMA's novel FITNESS DRIVER and CD3-targeted and synthetic car ligand (SCL) technologies, having the potential to provide a truly off-the-shelf solution for patients."

About GCAR^™: exumabio.com/our-science/#gcar-platform

About synthetic CAR ligand (SCL): exumabio.com/our-science/#synthetic

About the FITNESS DRIVER: exumabio.com/our-science/#cd3-Targeted

About EXUMA Biotech
EXUMA Biotech is a clinical-stage biotechnology company advancing novel cell and gene therapy platforms for treating autoimmune diseases and cancer. The company's innovations aim to reduce the cost and complexity of cell therapies while improving safety and efficacy for patients.
For additional information and access to a virtual copy of the poster presented, visit exumabio.com.

Contact:
Gregory R. Wade, Ph.D.
Chief Business Officer & Head of Finance
[email protected]

SOURCE EXUMA Biotech, Corp.