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.
Patient must be at least 18 years of age
Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status of 0-1
Patient must have histologically or cytologically confirmed microsatellite stable (MSS) or mismatch repair (MMR) protein expression proficient primary gastric or gastroesophageal adenocarcinoma (Siewert 3) with synchronous cytology positive disease (cyt+) OR peritoneal carcinomatosis detected by imaging, laparoscopy or laparotomy. Patients with microsatellite instability-high (MSI-H/dMMR) mismatch repair deficient disease are not eligible
Patient must have received a minimum of 3 months and a maximum of 6 months of first line systemic treatment
None
Parallel
Standard of Care Chemotherapy
DrugThe most common regimens are FOLFOX, CAPOX, FLOT, CF, and CX. Other local institutional standard of care regimens as well as targeted agents for gastric/GEJ adenocarcinoma are allowed.
Biospecimen Collection
Procedure/SurgeryPlasma is to be submitted at baseline and every three months for the first year or until progression, whichever comes first. For patients who have progression, their last plasma sample should be at time of progression.
Computed Tomography
Procedure/SurgeryRestaging imaging with CT and/or diffusion weighted MRI with contrast will be obtained after completion of 12 weeks (+/- 2 weeks) of assigned treatment (restaging will occur at this timepoint, regardless of if the patient completed all 4 cycles or not). At this point, patients with stable disease or a response will continue assigned treatment. In the absence of radiological or clinical progression, if clinically indicated by treatment team, patients may undergo diagnostic laparoscopy to assess surgical candidacy at which time a PCI assessment and biopsies of peritoneal nodules, peritoneal lavage could be performed. Cytoreduction can be offered to patients with a PCI \< 7 and if complete cytoreduction is feasible based on treating surgeon's discretion. If deemed a candidate for surgical cytoreduction, surgery should be performed within 6 weeks of the last study treatment in both arms.
Diagnostic Laparoscopy
Procedure/SurgeryAfter induction of general anesthesia, administration of preoperative antibiotics and placement of appropriate laparoscopic ports, peritoneal lavage will be performed by instillation of 200 ml of normal saline in the left upper quadrant and allowed to dwell for 5 minutes after which it will be aspirated for cytology. Extent of peritoneal disease burden will be ascertained as per the Peritoneal Cancer Index (PCI) scoring system as outlined in Appendix V.
Intraperitoneal Port Placement
Procedure/SurgeryPatients assigned to Arm B will undergo placement of indwelling tunneled intraperitoneal port with Teflon cuff following Step 1 randomization and during the diagnostic laparoscopy procedure.
Magnetic Resonance Imaging
Procedure/SurgeryRestaging imaging with CT and/or diffusion weighted MRI with contrast will be obtained after completion of 12 weeks (+/- 2 weeks) of assigned treatment (restaging will occur at this timepoint, regardless of if the patient completed all 4 cycles or not). At this point, patients with stable disease or a response will continue assigned treatment. In the absence of radiological or clinical progression, if clinically indicated by treatment team, patients may undergo diagnostic laparoscopy to assess surgical candidacy at which time a PCI assessment and biopsies of peritoneal nodules, peritoneal lavage could be performed. Cytoreduction can be offered to patients with a PCI \< 7 and if complete cytoreduction is feasible based on treating surgeon's discretion. If deemed a candidate for surgical cytoreduction, surgery should be performed within 6 weeks of the last study treatment in both arms.
Intraperitoneal Paclitaxel
DrugPatients on Arm B will start systemic therapy + intraperitoneal paclitaxel as early as the day after Step 1 randomization and must start within 30 calendar days (including holidays) after Step 1 randomization as per the schedule shown in the table below. Therapy will be administered on Days 1 and 8 of a 21-day cycle for 4 cycles.
Progression free survival (Phase II)
For the Phase II portion, full information is expected to occur 12 months after accrual or 38 months after study activation. This power calculation is based on a stratified log rank test and accounts for a planned interim analysis at 50% information time. At 50% information time, futility test using Wieand rule would be conducted. If the study results show promising results for the investigational arm and reject the null hypothesis at interim efficacy analysis, the study will proceed to investigate Phase III portion without having a pause in accrual before starting Phase III. Otherwise, if the study is not futile at 50% information time (HR\>1), then the study will proceed and wait for the data to reach 100% information, meaning that the study will wait until the data is mature for Phase II analysis (projected to wait 12 months after end of the accrual to collect 58 PFS events).
Overall survival (Phase III)
For the Phase III portion, a futility interim analysis is planned at 50% information time, projected to occur 4.3 years after study activation. However, because of the potential one year pause before starting Phase III portion, the futility interim analysis may occur early. Similar to the Phase II portion, the interim analysis for futility would use the Wieand rule to make sure the investigational arm is not doing worse than the control arm. For efficacy, interim analysis would start at 30% information time and be conducted every 6 months subsequently accordingly with the DSMC monitoring schedule. Approximately 1.5 additional years after completion of accrual, the OS analysis will reach 100% information time with 105 OS events.
Incidence of adverse events
Safety and tolerability will be assessed by counting treatment-related grade 3 or higher toxicity events of the patients.
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ECOG-ACRIN Cancer Research Group
Lead sponsor
National Cancer Institute (NCI)
Collaborator
