DKN-01 in Combination with Tislelizumab ± Chemotherapy in Patients with Gastric Cancer

We are doing this study to learn more about how experimental drugs DKN-01 and tislelizumab work in your body and against your cancer. We will compare how these drugs works together and in combination with another drug combination called CAPOX (capecitabine and oxaliplatin).

Advanced or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma

Adults ages 18 and older who:
- Are diagnosed with gastric adenocarcinoma or GEJ adenocarcinoma
- Have not been previously treated with an anti-DKK1 therapy, PD-1, anti-PD-L1, or anti-PD-L-2 therapy
- Do not have known osteoblastic bony metastasis

If you choose to join this study, you will:
- Go through a screening period to see if you're eligible for the study
- Have a tumor biopsy done, if necessary

If you're eligible to join, you will:
- Have physical exams
- Give blood samples
- Have other tests done during your clinic visits
- Be placed into 1 of 2 groups depending on when you join the study
-- Group A will receive study drugs DKN-01 and tislelizumab along with oxaliplatin IV once every 3 weeks and will take capecitabine by mouth twice a day for 2 weeks then hold for 1 week
-- Group B will receive study drugs DKN-01 and tislelizumab IV once every 3 weeks