A Study of ASP1002 in Adults for Treatment of Solid Tumors

The main aims of this study are: * To check the safety of ASP1002 in people with certain solid tumors. * To check if the people can tolerate ASP1002. * To find a suitable dose of ASP1002. This study will be in 2 parts. In Part 1, different small groups of people will receive lower to higher doses of ASP1002. Any medical problems will be recorded at each dose. This is done to find suitable doses of ASP1002 to use in Part 2 of the study. In Part 2, other different small groups of people will receive doses of ASP1002 that worked the best in Part 1. People in this study will be adults with metastatic or locally advanced solid tumors with high levels of a protein called claudin 4. The people's cancer will have either spread to other parts of the body (metastatic) or spread to tissue close by (locally advanced). They will have been previously treated with available standard therapies or refused to receive those treatments. In both parts of the study, ASP1002 (the study treatment) will be given to people slowly through a tube into a vein. This is called an infusion. This will happen every week, every other week, or every 3 weeks, in treatment cycles. Treatment cycles may be 21 days or 28 days long. People in this study will continue treatment for up to 2 years until: they have medical problems that prevent them from continuing treatment; their cancer gets worse; they start other cancer treatment; they ask to stop treatment; they do not come back for treatment. During the study, people will visit the clinic several times for a health check. This includes standard safety checks and reporting any medical problems. Every few weeks, the study doctors will check if each person's cancer has stayed the same or got worse. This will be done by scans (CT or MRI scans). Tumor samples will be taken during the study and people will have the option of giving a tumor sample after treatment has finished. People will visit the clinic within 7 days after stopping treatment for a health check. Then, they may visit the clinic at 1 month and 3 months after stopping treatment for further health checks. People will have follow-up health checks for up to 1 year after their last dose of ASP1002.