αDC1 Vaccine + Chemokine Modulatory Regimen (CKM) as Adjuvant Treatment of Peritoneal Surface Malignancies

This trial will evaluate the safety and effectiveness of autologous alpha-type-1 polarized
dendritic cell (alpha-DC1) vaccines (patients' autologous alpha-DC1s loaded with autologous
tumor material), combined with a systemic chemokine modulation regimen [CKM; intravenous
rintatolimod (TLR3 ligand, a derivative of Poly-I:C) + intravenous interferon-alfa + oral
celecoxib] as adjuvant therapy, after cytoreductive surgery (CRS) and hyperthermic
intraperitoneal chemotherapy (HIPEC), in patients with peritoneal surface malignancies (PSM),
including but not limited to malignant peritoneal mesothelioma and peritoneal carcinomatosis
(PC) of appendiceal and colorectal origin.

All patients judged to have peritoneal surface malignancy and considered able to be
cytoreduced to Peritoneal Cancer Index (PCI) Completeness of Cytoreduction (CC) score of 1 or
less will undergo CRS + HIPEC. Postoperative immunotherapy will start at least 4 weeks after
CRS + HIPEC.

Immunotherapy regimen will include four cycles of intranodal (3M cells) and intradermal (3M
cells) αDC1 vaccines. Each booster αDC1 vaccine dose (treatment cycles 2-4) will be followed
by 4-days of systemic CKM, starting the day after vaccination (IFNα [dose-escalation: 5-20
MU/m2], intravenous [IV], once a day for 4 days; rintatolimod [short-half-life TLR3 ligand]
200 mg intravenous [IV], on Wednesday and Friday only of the CKM regimen; and celecoxib 200
mg, orally, twice a day for 4 days). In order to avoid overlap between experimental
immunotherapy and potential adjuvant chemotherapy (which can be clinically indicated as a
part of standard care in the subset of patients), the experimental treatments will be
interrupted after cycles 1 and 2, to allow adjuvant chemotherapy that is done for each
patient's clinical care, and is not a part of this research study. Whenever clinically
indicated as a part of standard care, adjuvant chemotherapy may start at least 5 days after
completion of the 2nd cycle of immunotherapy (first booster vaccine plus the first CKM). The
3rd cycle of immunotherapy may start at least 5 days after the completion of chemotherapy.

Inclusion Criteria:

- Patients with histologically confirmed peritoneal surface malignancies, including but
not limited to malignant peritoneal mesothelioma and peritoneal carcinomatosis (PC)
from presumed appendiceal and colorectal primary tumors. Most patients will have
received extensive prior treatments, due to the recurrent nature of PC. Prior
therapies involve previous CRS, local and systemic chemotherapies. None of these prior
treatments disqualifies the patient from receiving the protocol-mandated experimental
treatment.

- Patients must be deemed able to undergo optimal cytoreductive surgery (CRS) defined as
CC-score of 0 or 1 based on imaging.

Cytoreduction is defined as the burden of residual disease nodules left at the end of
surgery (CC-0: no visible disease; CC-1: residual tumor nodules ≤ 2.5 mm in size; CC-2:
residual tumor nodules 2.5 mm - 2.5 cm in size; CC-3: residual tumor nodules > 2.5 cm in
size).

- Patients may be enrolled in the study regardless of prior chemotherapy regimens

- An ECOG performance status of 0, 1 or 2

- Age equal to 18 years or older

- Patients must be able to understand and be willing to sign a written informed consent
document

- Able to swallow pills

- Must have normal organ and marrow function as defined below:

Platelet ≥ 75,000/µL Hemoglobin ≥ 9.0 g/dL Hematocrit ≥ 27.0% Absolute Neutrophil Count
(ANC) ≥ 1500/µL WBC >2000/mm3 Creatinine < 1.5 x institutional upper limit of normal (ULN),
OR Creatinine clearance ≥ 50 mL/min/1.73 m2 for patients with creatinine levels greater
than 1.5 x ULN Total bilirubin ≤ 1.5 x ULN AST(SGOT) and ALT(SGPT) ≤ 2.5 X ULN

Exclusion Criteria:

- Patients on systemic immunosuppressive agents, including steroids. Patients who are
able to be removed from immunosuppressives at least 3 weeks prior to the first vaccine
will be considered eligible.

- Patients with active autoimmune disease or history of transplantation. Patients with
indolent or chronic autoimmune disease not requiring steroid treatment are considered
eligible.

- Patients who are pregnant or nursing

- Patients experiencing a cardiac events (acute coronary syndrome, myocardial
infarction, or ischemia) within the 3 months prior to accrual

- Patients with a New York Heart Association classification of III or IV

- Prior allergic reaction or hypersensitivity to celecoxib or NSAIDs