This is a Phase 1, multicenter, open-label study of DISP-10, a combination therapy consisting of DV-10 (adenovirus) and idecabtagene vicleucel (ide-cel, BCMA-directed chimeric antigen receptor [CAR] T), in adult participants with advanced gastrointestinal (GI) cancers.

The study will consist of 2 parts: dose-escalation (Part 1) and dose-expansion (Part 2). Part 1 of the study will evaluate the safety and tolerability of increasing dose levels of DISP-10 to establish the recommended dose for expansion (RDE); Part 2 will evaluate the safety and efficacy of DISP-10 in participants treated at the RDE.

Key Inclusion Criteria:

1. Histologically confirmed advanced or metastatic esophageal, gastroesophageal junction, gastric adenocarcinoma, or colorectal adenocarcinoma
2. Measurable disease according to RECIST v1.1 and at least 1 additional site of disease amenable to biopsy
3. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
4. Aged ≥18 years at time of signing informed consent
5. Adequate organ function

Key Exclusion Criteria:

1. Previous solid organ or hematopoietic cell transplant
2. Evidence of rapid disease progression, defined as radiographic or clinical progression within 3 months of the most recent prior line of therapy
3. Known history of hepatitis B or HIV infection
4. Previous or concurrent malignancy except if curatively treated more than 3 years prior to enrollment
5. Known active central nervous system (CNS) metastases
6. Clinically significant pleural or pericardial effusion or peritoneal carcinomatosis
7. Active treatment with antiviral agents
8. History of severe hypersensitivity to fludarabine or cyclophosphamide
9. Prior therapies/treatments with oncolytic viruses or T cell derived cellular therapy