A Study to Evaluate the Safety and Efficacy of A2B530, a Logic-gated CAR T, in Participants with Solid Tumors That Express CEA and Have Lost HLA-A*02 Expression

The goal of this study is to test A2B530,an autologous logic-gated Tmod™ CAR T-cell product in subjects with solid tumors including colorectal cancer (CRC), pancreatic cancer (PANC), non-small cell lung cancer (NSCLC), and other solid tumors that express CEA and have lost HLA-A*02 expression.

The main questions this study aims to answer are:

• Phase 1: What is the maximum or recommended dose of A2B530 that is safe for patients
• Phase 2: Does the recommended dose of A2B530 kill the solid tumor cells and protect the patient's healthy cells

Participants will be required to perform study procedures and assessments, and will also receive the following study treatments:

• Enrollment and Apheresis in BASECAMP-1 (NCT04981119)
• Preconditioning Lymphodepletion (PCLD) Regimen
• A2B530 Tmod CAR T cells at the assigned dose

This is a phase 1/2, multi-center, open-label study that enrolls adult subjects with recurrent unresectable, locally advanced, or metastatic (considered non-curative) CRC, NSCLC, PANC, or other solid tumors with CEA expression. Subjects must be germline HLA-A*02 heterozygous, with tumors that express CEA and somatic loss of HLA-A*02. The purpose of Phase 1 of this study is to determine the safety and the optimal dose of A2B530 (after PCLD) in participants with solid tumor disease. The purpose of Phase 2 of this study is to determine the further safety and efficacy (how well it treats the solid tumor disease) of A2B530.

The treatment available for these cancers and other solid tumors can be toxic, debilitating, and fatal. In the recurrent unresectable, locally advanced, or metastatic setting, the intent of standard of care treatment is typically palliative rather than curative, and has not changed significantly in several decades. A2 Bio hypothesizes that A2B530 Tmod CAR T-cell therapy will enable the killing of tumor target cells (those cells that express CEA and have LOH for HLA-A*02 protein). Additionally, normal healthy cells that maintain HLA-A*02 expression and co-express CEA (eg, gut mucosal tissue) will not be targeted due to the blocker portion of the Tmod CAR T cell that acts as a self-regulated safety switch that protects normal tissue from damage. A2 Bio believes this will provide a therapeutic safety window compared to previous solid tumor targeting therapies. This hypothesis will be explored in the study.

Participants for this study must enroll and have their T cells collected (apheresis) in the pre-screening BASECAMP-1 study (NCT04981119). T cells are collected, processed and stored for each participant. Upon disease progression the participant may screen for this study (EVEREST-1) and the participant's T cells are then manufactured and infused following PCLD regimen. There is no time requirement between the studies, and patients may go directly from BASECAMP-1 to EVEREST-1 based on their own disease course.