Inclusion Criteria:

          1. Patients must have stage IV peritoneal surface dissemination of gastrointestinal
             cancer or recurrent ovarian, fallopian tube or primary peritoneal cancer with
             metastatic disease to the peritoneum that cannot be completely resected at time of
             abdominal exploration. Please note:

               1. Locoregional extension of peritoneal disease beyond the peritoneal cavity
                  (including but not limited to the pleura and subcutaneous soft tissue) is
                  permitted with PI approval,

               2. Radiographically measurable disease is preferable, but for patients with
                  previously documented gastrointestinal, fallopian tube, ovarian, or primary
                  peritoneal cancer, for whom relevant tumor markers (including but not limited to
                  CEA, CA 19-9 or CA-125) have been useful markers of disease progression and/or
                  response to treatment, an elevated relevant tumor marker (including but not
                  limited to CEA, CA 19-9 or CA-125) above the institutional upper limit of normal
                  could be substituted for radiographic imaging,

               3. Asymptomatic primary tumors are permitted.

          2. Subjects must have had at least one prior round of systemic therapy or have refused or
             be ineligible for standard systemic therapy for their disease type. No prior systemic
             therapy is required for low grade mucinous cancers.

          3. Age ≥ 18 years

          4. Eastern Cooperative Oncology Group (ECOG) Performance Score of 0-2

          5. Adequate marrow function as evidenced by:

               1. Absolute neutrophil count (ANC) ≥ 2,000/µL

               2. Platelets ≥ 100,000/µL

               3. Hemoglobin (Hgb) ≥ 9 g/dL

          6. Adequate renal function as evidenced by serum creatinine ≤ 1.5 x upper limit of normal
             (ULN), OR 24-hour creatinine clearance ≥ 60 mL/min for subject with creatinine levels
             > 1.5 x ULN.

          7. Adequate hepatic function as evidenced by:

               1. Serum bilirubin ≤ 1.5 x ULN OR direct bilirubin ≤ ULN for a subject with total
                  bilirubin level > 1.5 x ULN

               2. Aspartate aminotransferase (AST) ≤ 3 x ULN

               3. Alanine aminotransferase (ALT) ≤ 3 x ULN

               4. Alkaline phosphatase ≤ 3 x ULN

          8. INR or PT ≤ 1.5 x ULN, unless the subject is receiving anticoagulant therapy, in which
             case PT and PTT/aPTT must be within therapeutic range of intended use of
             anticoagulants (and may need to be held per institutional standards for placement of
             the Bard peritoneal catheter).

          9. Patients must be recovered from both acute and late effects of any prior surgery,
             radiotherapy or other antineoplastic therapy.

         10. Patients of reproductive potential (men and women) must agree to use medically
             accepted barrier methods of contraception (e.g., male or female condom) at the time of
             pregnancy test (women of childbearing potential only), during the course of the study
             and for 90 days after the last dose of study drug, even if oral contraceptives are
             also used. All subjects of reproductive potential must agree to use both a barrier
             method and a second method of birth control during the course of study and for 90 days
             after the last dose of study drug.

         11. Patients or their legal representatives must be able to read, understand and provide
             informed consent to participate in the trial.

        Exclusion Criteria:

          1. Prior chemotherapy, radiotherapy, biological cancer therapy, targeted therapy, or
             major surgery within 28 days prior to enrollment or has not recovered to CTCAE grade 1
             or better from adverse event due to cancer therapy administered more than 28 days
             prior to enrollment.

          2. Patients who received radiotherapy to more than 25% of their bone marrow.

          3. Currently receiving treatment with another investigational device or drug study, or <
             30 days since ending treatment with another investigational device or drug study(s).
             Other investigational procedures while participating in this study are excluded.

          4. Known active central nervous system (CNS) metastases. Subjects with previously treated
             brain metastases may participate provided they are stable (without evidence of
             progression by imaging for at least four weeks prior to the first dose of trial
             treatment and any neurologic symptoms have returned to baseline), have no evidence of
             new or enlarging brain metastases, and are not using steroids >10 mg/day of prednisone
             or equivalent. The exception does not include carcinomatous meningitis, which is
             excluded regardless of clinical stability.

          5. Metastatic disease in a site other than the peritoneal surfaces. Note: Locoregional
             extension of peritoneal disease may be permitted with PI approval.

          6. History or evidence of active autoimmune disease that requires systemic treatment
             (i.e., with use of disease modifying agents, corticosteroids, or immunosuppressive
             drugs). Replacement therapy (e.g., thyroxine, insulin, or physiologic corticosteroid
             replacement therapy for adrenal or pituitary insufficiency, etc.) is not considered a
             form of systemic treatment.

          7. Evidence of clinically significant immunosuppression such as the following:

               1. Primary immunodeficiency state such as Severe Combined Immunodeficiency Disease.

               2. Concurrent opportunistic infection.

               3. Receiving systemic immunosuppressive therapy (> 2 weeks) including oral steroid
                  doses >10mg/day of prednisone or equivalent within 7 days prior to enrollment.

          8. History of allogenic organ or hematopoietic transplant.

          9. Active herpes simplex virus (HSV) that requires intermittent or chronic systemic
             anti-herpetic therapy or prior complications of herpetic infection, e.g. herpetic
             keratitis or encephalitis.

         10. Requiring intermittent or chronic systemic (intravenous or oral) treatment with an
             antiherpetic drug (e.g., acyclovir), other than intermittent topical use.

         11. Prior treatment with talimogene laherparepvec or any other oncolytic virus.

         12. Subject has known sensitivity to talimogene laherparepvec or any of its components to
             be administered during dosing.

         13. Prior therapy with tumor vaccine.

         14. Receipt of a live vaccine within 28 days prior to enrollment.

         15. Known to have acute or chronic active hepatitis B or C infection (active, previously
             treated, or both).

         16. Known history of HIV infection.

         17. Active infection or fever ≥ 101.3°F within 3 days of the first scheduled day of
             protocol treatment.

         18. Peripheral neuropathy ≥ Grade 2.

         19. Bleeding disorders that would preclude intraperitoneal port placement.

         20. Refractory ascites that requires palliative paracentesis more frequently than once a
             month. 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 interferes with the
             interpretation of the results.

         21. History of other malignancy within the past 5 years.

         22. Female subjects who are pregnant or breast-feeding, or planning to become pregnant
             during study treatment or through 90 days after the last dose of talimogene
             laherparepvec.

         23. Subjects of childbearing potential who are unwilling to use acceptable method(s) of
             effective contraception during study treatment and through 90 days after the last dose
             of talimogene laherparepvec.

         24. Sexually active subjects and their partners unwilling to use male or female latex
             condom to avoid potential viral transmission during sexual contact while on treatment
             and within 90 days after treatment with talimogene laherpareapvec.