Intraperitoneal Docetaxel in Combination With mFOLFOX6 for Gastric Cancer Patients With Peritoneal Carcinomatosis

Inclusion Criteria: * Have histologically-confirmed GC-PC by diagnostic laparoscopy who have not undergone chemotherapy for metastatic/recurrent disease. * Be willing and able to provide written informed consent/assent for the trial. * Be ≥ 18 years of age on day of signing informed consent. * Not have distant metastases as ruled out by an initial imaging (e.g. CT Chest/Abdomen/Pelvis with contrast), positron emission tomography (PET scan). Any metastasis in distant organs other than the peritoneum will exclude the patient from this study. * Have a performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) Performance Scale at study entry. * Demonstrate adequate organ function. All screening labs should be performed within 7 days prior to protocol therapy. * Female subject of childbearing potential should have a negative urine or serum pregnancy within 72 hours prior to receiving the first dose of study medication. If the urine test is positive or cannot be confirmed as negative, a serum pregnancy test will be required. * Female subjects of childbearing potential should be willing to use 2 methods of birth control or be surgically sterile, or abstain from heterosexual activity for the course of the study through 120 days after the last dose of study medication. Subjects of childbearing potential are those who have not been surgically sterilized or have not been free from menses for \> 1 year. * Male subjects should agree to use an adequate method of contraception starting with the first dose of study therapy through 120 days after the last dose of study therapy. * Willingness to undergo intraperitoneal port placement Exclusion Criteria: * Has gastric cancer involving the distal esophagus above the gastroesophageal (GE) junction (Siewart type 1, proximally), or second portion of the duodenum (distally). * Is currently participating in or has participated in a study of an investigational agent or using an investigational device within 4 weeks of the first dose of treatment. * Has a tumor positive for human epidermal growth factor receptor 2 (HER2) staining. * Has had prior surgery with dense intra-abdominal adhesions * Has a diagnosis of immunodeficiency or is receiving systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of trial treatment. * Has had a prior monoclonal antibody within 4 weeks prior to study Day 1 or who has not recovered (i.e., ≤ Grade 1 or at baseline) from adverse events due to agents administered more than 4 weeks earlier. * Has had prior chemotherapy, targeted small molecule therapy, or radiation therapy within 4 weeks (6 weeks for nitrosureas or mitomycin C) prior to study Day 1 or who has not recovered (i.e., ≤ Grade 1 or at baseline) from adverse events due to a previously administered agent. * Has a known additional malignancy that is progressing or requires active treatment. Exceptions include basal cell carcinoma of the skin, squamous cell carcinoma of the skin, or in situ cervical cancer that has undergone potentially curative therapy. * Has known central nervous system (CNS) metastases and/or carcinomatous meningitis. * Has an active infection requiring antibiotic therapy. * Has a history or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the trial, interfere with the subject's participation for the full duration of the trial, or is not in the best interest of the subject to participate, in the opinion of the treating investigator. * Has any other medical condition, including mental illness or substance abuse, deemed by the Investigator to be likely to interfere with a patient's ability to sign informed consent, cooperate and participate in the study, or interfere with the interpretation of the results. * Is pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the pre-screening or screening visit through 120 days after the last dose of trial treatment. * Has a known history of Human Immunodeficiency Virus (HIV) (HIV 1/2 antibodies). * Has known active Hepatitis B (e.g., HBsAg reactive) or Hepatitis C virus (e.g., Hepatitis C virus RNA \[qualitative\] is detected). * Patients receiving any medications or substances that are inhibitors or inducers of Cytochrome P450 3A4 (CYP 3A4) are ineligible. Investigator can change to a similar agent that is a non-CYP3A4 inhibitor/inducer with a washout period of 1 week. * Patients with known hypersensitivity to any of the components of docetaxel or mFOLFOX6. * Patients who received pelvic or abdominal radiotherapy. * Peripheral neuropathy ≥ Grade 2. * History of allogeneic transplant. * Any known cardiac abnormalities, in accordance with mFOLFOX6 guidelines. * Any other condition that would render the patient to be unfit for the trial as deemed by the PI or clinical team.