Study on Bemarituzumab with Other Cancer Treatments for Advanced Stomach or Gastroesophageal Junction Cancer

Inclusion Criteria

• Adults with advanced stomach or gastroesophageal junction cancer that cannot be removed by surgery.
• Able to provide a tumor sample, either from a previous test within the last 6 months or a new biopsy.
• For some parts of the study, the cancer must show a specific marker called FGFR2b.
• Good overall health with an ECOG performance score of 0 or 1, meaning fully active or restricted in physically strenuous activity but ambulatory.
• Cancer that can be measured or evaluated by standard criteria.
• No issues with receiving the combination of treatments being tested.
• Adequate organ function as determined by medical tests.
• For certain parts of the study, the cancer must be measurable by specific criteria.

Exclusion Criteria

• Previous treatment for advanced or inoperable cancer (except if prior treatment for local disease ended more than 6 months ago).
• Previous treatment with drugs targeting the FGF-FGFR pathway.
• Cancer that is HER2 positive.
• Untreated or symptomatic brain cancer or central nervous system disease.
• Severe nerve damage.
• Significant heart disease.
• Other cancers within the last 2 years, unless fully treated.
• Chronic eye diseases.
• Major surgery or participation in another study within 28 days before starting this study.
• Recent palliative radiotherapy within 14 days before starting this study.
• Eye conditions that increase the risk of corneal ulcers.
• Systemic diseases or eye disorders requiring long-term use of eye steroids.