The purpose of this study is to determine the impact of antibiotic therapy on the disease progression and overall survival of patients with Pseudomyxoma Peritonei (PMP).

Single center, open label, historical controlled, phase II study that proposes two courses of standard H. Pylori eradication antibiotic therapy can suppress carcinogenesis and improve the long-term outcomes of patients with PMP. The first course of antibiotics (PrevPac) will be administered before cytoreductive surgery and HIPEC and the second course afterwards. The historical control group will consist of all PMP patients from Mercy Medical Center's Tumor Registry who did not receive perioperative antibiotic treatment. Long-term statistical outcomes will be calculated using the Kaplan-Meier method and Cox proportional hazard ratio to compare pertinent variable. 80 subjects to be enrolled over 2 years, with a 5 year follow-up period.

Inclusion Criteria:

• Patients must have measurable pseudomyxoma peritonei from appendiceal origin, confirmed by histology, cytology, or radiographical evidence -
• Age ≥ 21 years
• Eastern Cooperative Oncology Group (ECOG) performance status score≤2/Karnofsky performance status of (KPS) ≥ 70% (see Appendix B)
• Patients must have normal organ and marrow function as defined below:

Absolute neutrophil count (ANC) ≥1,000/mm3 Platelets ≥100,000/mm3 Hemoglobin ≥ 8.5 g/dL

Renal function:

Creatinine ≤1.5 times the upper limit of normal (ULN) or calculated creatinine clearance ≥60ml/min

Hepatic function:

Bilirubin ≤1.5 times ULN Alanine aminotransferase (ALT) ≤3 times ULN Aspartate aminotransferase (AST) ≤3 times ULN

• Ability of subject or Legally Authorized Representative (LAR) to understand and willingness to sign a written informed consent, approved by Mercy Medical Center Institutional Review Board (IRB)
• A negative pregnancy test for women of childbearing age with all reproductive organs intact

Exclusion Criteria:

• Patients receiving any other investigational agents
• Presence of other invasive malignancies or evidence of another cancer present within the last 3 years, excluding skin cancer
• history of, or known allergic reaction/hypersensitivity to PREVPAC or any component of similar chemical or biologic composition to PREVPAC
• Patients < 21 of age
• Pregnancy or lactation at the time of proposed assignment. Pregnant women are excluded from this study because PREVPAC is based on the pregnancy category for clarithromycin which is Category C agent with the potential for teratogenic or abortifacient effects. These potential risks may also apply to CRS/HIPEC.
• Assessed by the investigator to be unable or unwilling to comply with the requirements of the protocol (e.g., unable to swallow pills)
• Psychiatric or addictive disorders or other conditions that, in the opinion of the investigator, would preclude the patient from meeting the study requirements or giving informed consent
• Known active acute hepatitis and confirmed diagnosis of Human Immunodeficiency Virus (HIV) infection. HIV-positive patients on combination antiretroviral therapy are ineligible. These patients are at increased risk of lethal infections when treated with marrow-suppressive therapy.
• Active systemic infection that requires use of parenteral antibiotics
• Renal insufficiency with serum creatinine level ≥1.5 times the upper limit of normal or calculated -
• Patients with concurrent severe medical problems unrelated to malignancy that will preclude compliance with the study or places at an unacceptable risk for participation in the study determinate by study investigators
• Patients to be maintained on any medication having severe interactions with PREVPAC