Testing the Addition of Paclitaxel Administered Into the Abdominal Cavity Combined With Chemotherapy for Patients With Gastric Cancer Spread to the Abdominal Cavity

This study is being done to answer the following questions: Can we lower the chance of your gastric cancer from growing or spreading by administering paclitaxel chemotherapy directly into your abdominal cavity in addition to chemotherapy given through a vein in your arm? Will administering paclitaxel chemotherapy directly into your abdominal cavity, in addition to chemotherapy given through a vein in your arm help you live longer? We are doing this study because we want to find out if this approach is better or worse than the usual approach for your gastric cancer. The usual approach is defined as care most people get for gastric cancer. If you decide to take part in this study, you will first receive a surgical procedure called a diagnostic laparoscopy. This will help the study doctors learn more about your gastric cancer. Laparoscopy is a minimally invasive surgery for which you will be placed under general anesthesia. Then the surgeon will make small incisions (5mm) on your belly through which a camera and thin instruments are introduced to evaluate the abdomen. This procedure takes about 1 hour to complete. Your study group will be assigned during the surgery. The study groups are described further in the 'What are the study groups?' section below. If you are placed into the study group 1, you will not have an intraperitoneal port (a small device which is placed under the skin and fat of your upper abdomen and a tube that is placed into the abdomen). If you are placed into the study group 2, you will have an intraperitoneal port placed. The reason is that in addition to standard chemotherapy, which is given through a vein in your arm, this port will be used to deliver the medication paclitaxel directly inside your abdomen when you are ready to start study treatment. It is important to know that you will not know your study group until after the surgery is over. This is because information that is learned during the surgery will help determine which study group you are put in. Once you have fully healed from this surgery, you will start study treatment. Depending on which study group you are assigned, you will either receive a standard chemotherapy regimen (the regimen will be chosen by you and your doctor) if you are in study group 1, or paclitaxel through a tube in your belly plus chemotherapy given through a vein in your arm if you are in study group 2. All participants will get treatment for three (3) months after which you will undergo reevaluation. If the disease is under control or responding to treatment, you may continue the assigned treatment until your disease gets worse, the side effects become too severe, or you may be offered a surgical procedure to remove the cancer if the amount of disease is low and can be completely removed as determined by a surgeon. There is a very small chance that during the laparoscopy surgical procedure, the doctor might find something called "intra-abdominal adhesions". These are areas where the stomach has healed previously and created scar tissue. If this scar tissue prevents the surgeon from being able to place a port in the correct area, you would be ineligible to receive the study treatment. If this happens, you may still receive standard of care therapy after your surgery, but you will not be able to continue on the study. If you have more questions about this, you can ask your surgeon or the study team to help. After you finish your study treatment, your doctor or study team will watch you for side effects. They will continue to follow your condition every three (3) months during the first two (2) years, then every six (6) months until year 5. You may be reevaluated with Chest/Abdomen/Pelvis scans every three-six (3-6) months for up to five (5) years if decided by your doctor.

PRIMARY OBJECTIVES: I. In the phase II portion, to determine the progression free survival (PFS) from randomization. II. In the phase III portion, to determine overall survival (OS) from randomization. SECONDARY OBJECTIVE: I. To compare the safety and tolerability of the intraperitoneal chemotherapy + systemic therapy regimen vs the systemic therapy alone regimen. OUTLINE: STEP 0: Patients undergo diagnostic laparoscopy within 4 weeks of study registration. STEP 1: Patients are randomized to 1 of 2 arms at the time of Step 0 diagnostic laparoscopy. ARM A: Patients receive standard of care systemic therapy per physician's choice. Patients with stable disease or a response after 12 weeks may continue to receive standard of care treatment in the absence of disease progression or unacceptable toxicity. Patients undergo blood sample collection and computed tomography (CT) and/or magnetic resonance imaging (MRI) throughout the study and may undergo additional diagnostic laparoscopies as clinically indicated. ARM B: Patients undergo placement of an intraperitoneal port. Patients receive leucovorin calcium intravenously (IV) over 15-30 minutes, fluorouracil IV push, paclitaxel IV over 1-2 hours and paclitaxel intraperitoneally (IP) on days 1 and 8 of each cycle. Cycles repeat every 21 days for up to 4 cycles in the absence of disease progression or unacceptable toxicity. Patients with stable disease or a response after 12 weeks may continue to receive treatment in the absence of disease progression or unacceptable toxicity. Patients undergo blood sample collection and CT and/or MRI throughout the study and may undergo additional diagnostic laparoscopies as clinically indicated. After completion of study treatment, patients are followed up every 3 months for 2 years then every 6 months for up to 5 years after Step 1 randomization.