Inclusion Criteria:

          -  ECOG 0 to 1.

          -  Adequate organ function within 2 weeks of starting study treatment.

          -  Prior to the first dose of MEDI1191, subjects with central nervous system (CNS)
             metastases must have been treated and must be asymptomatic.

          -  Cessation of systemic corticosteroids at doses exceeding 12 mg/day prednisone or
             equivalent, methotrexate, azathioprine, ustekinumab (Stelara®), and tumor necrosis
             factor (TNF)-α/IL-6 blockers for at least 7 days prior to the first dose of MEDI1191.

          -  Subjects must have at least one lesion suitable for intratumoral dosing for
             superficial lesions but at least two lesion suitable for intratumoral dosing for
             deep-seated lesions.

          -  Subjects must have at least one non-injected lesion that can be measured by RECIST
             v1.1.

          -  Histologic or cytologic confirmation of advanced solid tumor.

          -  Received and have progressed on or refractory to at least 1 line of standard systemic
             therapy in the recurrent/metastatic setting.

          -  Highly effective method of contraception from screening, and must agree to continue
             using such precautions for 3 months after the final dose of investigational product.

          -  Nonsterilized male subjects who are sexually active with a female partner of
             childbearing potential must use a male condom with spermicide from Day 1 through 6
             months after receipt of the final dose of investigational product.

        Exclusion Criteria:

          -  Subjects who have received prior IL-12 either alone or as part of a treatment regimen.

          -  Subjects who were administered any live attenuated vaccines within 30 days prior to
             first MEDI1191 injection.

          -  Known allergy or hypersensitivity to any component of MEDI1191 or durvalumab
             formulations.

          -  Active or prior documented autoimmune disorders within the past 5 years prior to the
             first scheduled dose of study treatment except alopecia, hypothyroidism (stable of
             hormone replacement), chronic skin condition (does not require systemic therapy), and
             celiac disease (controlled by diet alone).

          -  Immune-deficiency states - myelodysplastic disorders, marrow failure states, human
             immunodeficiency virus infection, history of solid organ transplant, bone marrow
             allograft, or active tuberculosis.

          -  History of coagulopathy resulting in uncontrolled bleeding or other bleeding
             disorders.

          -  Require continuous anticoagulation or antiplatelet therapy (except for ≤ 100 mg
             acetylsalicylic acid [ASA]) which cannot be interrupted for more than 7 days for IT
             delivery of MEDI1191.

          -  Any concurrent chemotherapy, radiotherapy, immunotherapy, biologic or hormonal therapy
             for cancer.

          -  Receipt of any conventional or investigational anticancer therapy within 21 days or
             palliative radiotherapy within 7 days prior to the first dose of study treatment. For
             subjects who have received prior immunotherapy, the following additional exclusion
             criteria apply:

               1. Received only one dose of prior immunotherapy agent alone or as part of a
                  combination regimen

               2. Experienced a toxicity that led to permanent discontinuation of prior
                  immunotherapy

               3. All AEs while receiving prior immunotherapy did not resolve to ≤ Grade 1 or
                  baseline prior to screening for this study.

               4. Experienced a ≥ Grade 3 AE (including pneumonitis) or neurologic, ocular, or
                  cardiac AE of any grade while receiving prior immunotherapy.

               5. Required the use of additional immunosuppression other than corticosteroids for
                  the management of an AE, or experienced recurrence of an AE if re-challenged, or
                  is currently requiring a maintenance dose of > 12 mg prednisone or equivalent per
                  day.

          -  Any toxicity from prior therapy that has not completely resolved to ≤ Grade 1 or
             baseline at the time of consent.

          -  Current or prior use of immunosuppressive medication within 14 days prior to the first
             dose of MEDI1191, except intranasal, topical, inhaled corticosteroids, local steroid
             injections, systemic corticosteroids at physiologic doses not to exceed 12 mg/day of
             prednisone or equivalent, or steroids as premedication for hypersensitivity reactions.

          -  Cardiac exclusions: New York Heart Association Class 3 or 4 congestive heart failure,
             uncontrolled hypertension, acute coronary syndrome within 6 months.

          -  Any condition that would interfere with evaluation of the investigational product or
             interpretation of subject safety or study results.

          -  Uncontrolled intercurrent illness.

          -  Untreated, active hepatitis B or C.

          -  Major surgery within 4 weeks prior to first dose of MEDI1191 or still recovering from
             prior surgery.

          -  Subjects with untreated active major depression with suicidal ideation and/or plan.

          -  Female subjects who are pregnant, lactating, or intend to become pregnant during their
             participation in this study.