A Study of ASP2138 Given by Itself or Given With Other Cancer Treatments in Adults With Stomach Cancer, Gastroesophageal Junction Cancer, or Pancreatic Cancer

Study Summary

Claudin 18.2 protein, or CLDN18.2 is a protein found on cells in the digestive system. It is also found on some tumors. Researchers are looking at ways to attack CLDN18.2 to help control tumors. ASP2138 is thought to bind to CLDN18.2 and a protein on a type of immune cell called a T-cell. This "tells" the immune system to attack the tumor. ASP2138 is a potential treatment for people with stomach cancer, gastroesophageal junction cancer (GEJ cancer) or pancreatic cancer. GEJ is where the tube that carries food (esophagus) joins the stomach. Before ASP2138 is available as a treatment, the researchers need to understand how it is processed by and acts upon the body. In this study, ASP2138 will either be given by itself, or given together with standard treatments for gastric, GEJ and pancreatic cancer. Pembrolizumab and mFOLFOX6, and ramucirumab and paclitaxel are standard treatments for gastric and GEJ cancer. mFOLFIRINOX is a standard treatment for pancreatic cancer. This information will help find a suitable dose of ASP2138 given by itself and together with the standard cancer treatments and to check for potential medical problems from the treatments. The main aims of the study are: * To check the safety of ASP2138 and how well people can tolerate medical problems during the study. * To find a suitable dose of ASP2138 to be used later in the study. * These are done for ASP2138 given by itself and when given together with the standard cancer treatments. Adults 18 years or older with stomach cancer, GEJ cancer, or pancreatic cancer can take part. Their cancer is locally advanced unresectable or metastatic. Locally advanced means the cancer has spread to nearby tissue. Unresectable means the cancer cannot be removed by surgery. Metastatic means the cancer has spread to other parts of the body. There should also be the CLDN18.2 marker in a tumor sample. People cannot take part if they need to take medicines to suppress their immune system, have blockages or bleeding i

Primary Outcome

A DLT is defined as any of the prespecified Adverse Events (AEs) (graded using National Cancer Institute Common Terminology Criteria for Adverse Events \[NCI-CTCAE\] version 5.0, except cytokine release syndrome \[CRS\] and immune effector cell-associated neurotoxicity syndrome \[ICANS\] which are graded using American Society for Transplantation and Cellular Therapy \[ASTCT\] consensus grading) or laboratory findings that the investigator or sponsor cannot clearly attribute to a cause other tha

Conditions Studied

Interventions

• DRUG Pembrolizumab
• DRUG Fluorouracil
• DRUG Leucovorin
• DRUG Oxaliplatin
• DRUG ASP2138

Study Locations (20)