The goal of this prospective phase 2 study is to assess the efficacy and safety of intestinal or multivisceral transplantation for participants with PMP not amenable to other curative-intent treatments. Participants will undergo intestinal/multivisceral transplantation. Participants will be followed for 12 months to assess efficacy and safety.

Pseudomyxoma peritonei (PMP) is a rare clinical entity (approximately 2-4 cases per million people) characterized by extensive dissemination of mucinous ascites in the abdominal cavity. Relentless accumulation of mucin causes progressive abdominal distention, intestinal obstruction, malnutrition, cachexia, and ultimately death. As a rare disease, diagnosis is often late, and usually occurs when the disease is in a clinically advanced stage. The prognosis of PMP has been dramatically improved by the introduction of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). While outcomes are favorable for participants with disease amenable to CRS+HIPEC, the therapeutic options for participants with unresectable PMP are limited. Intestinal transplantation represents a therapeutic option in participants with unresectable PMP. Overall survival has been shown to improve with participants with unresectable PMP during an Oxford Transplant Center study. The goal of this study is to corroborate the Oxford results on an American cohort.

Inclusion Criteria:

• Subjects must have histologically confirmed pseudomyxoma peritonei (PMP)

  • Both low-grade mucinous carcinoma peritonei (LMCP) or high-grade mucinous carcinoma (HMCP), with or without signet ring cells as well as primary or recurrent disease, will be eligible.

• PMP disease does not have any extra-abdominal metastases, with the exception of pulmonary involvement (nodal, parenchymal, and pleural).

• PMP disease is extensive and not amenable to operative management, with or without liver, pancreas, stomach, or abdominal wall involvement.

  • Definition of Non-Resectable Disease-

    • Non-resectable PMP disease will be defined as the presence of at least one of the following conditions:

      • 1) Extensive small bowel serosa involvement, where it is not possible to preserve at least 1.5-2 m of small bowel
      • 2) Extensive infiltration of the pancreatic surface
      • 3) Mesenteric involvement causing retraction
      • 4) Need for complete gastric resection
      • 5) Urete1ic obstruction
      • 6) Liver disease with no chance to achieve R0 resection with liver remnant volume > 30%
      • 7) Recurrent disease not amenable to further resection

• Subjects do not have any other available curative treatment options.

  • Subjects can have previous abdominal operations, including CRS+HIPEC.

• Age ≥ 18 and ≤ 75.

  • Pediatric participants were excluded as PMP is a disease that affects adults. Participants > 75 years of age are excluded as they are beyond the commonly accepted transplantability criteria.

• Performance status ECOG ≤ 1.

• Subjects must have the ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria:

• Subjects with peritoneal carcinomatous originating from an etiology other than PMP.
• Subjects receiving any other investigational agents.
• Subjects with uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would either put participation at risk because of participation in the study, may influence the result of the study, or limit compliance with study requirements.
• Pregnant women are excluded from this study because an intestinal transplant is a procedure that is not compatible with a viable pregnancy.
• Subjects who are HIV-positive may be included in the study. HIV testing is required for the study as adequate HIV treatment is required prior to intestinal transplant due to the increased risk of infection following transplantation and treatment with immunosuppressive agents.

As an investigator-initiated protocol, individual participant data will not need to be shared with any other third party. Reported results from this trial will be aggregated data.