Inclusion Criteria:

All of the following conditions should be met at screening:

1. Male or female patients 18-75
2. Patients with malignant solid tumors that have been diagnosed by pathology and/or cytology
3. Patients who have progressed on or who cannot tolerate available therapies or for whom curative therapy does not exist
4. Patients with at least one non-injected measurable tumor lesion per RECIST v1.1
5. Patients with lesions suitable for intratumoral injection (the lesion length is at least 10 mm and not exceeding 80 mm)
6. Patients enrolled in the single and multiple administration stages of Phase 1a must agree to provide pre- and post-treatment tumor biopsy tissues
7. Patients must have adequate organ and marrow functions
8. Patients with treated brain metastases are eligible if meeting protocol's requirement
9. Patients must be ≥ 4 weeks beyond treatment with any chemotherapy (6 weeks for nitrosoureas or mitomycin C), hormonal, biological, targeted agents, other investigational therapy or radiotherapy

Exclusion Criteria:

Patients who meet any of the following criteria will be excluded from study entry:

1. Patients who have received prior IL-12 either alone or as part of a treatment regimen
2. Patients who have received prior therapy with an immuno-oncology agent and were discontinued from that treatment due to a Grade 3 or higher immune-related adverse event (irAE)
3. Patients requiring therapeutic doses of anticoagulation
4. Patients with tumors that impinge on major airways, blood vessels, or nerve bundles
5. Patients with a history of autoimmune disease that has the possibility of recurrence or active autoimmune disease that requires immunosuppressive medications
6. Patients who had a major surgical procedure within 4 weeks prior to the first dose of study treatment
7. Current or prior use of immunosuppressive medication within 2 weeks prior to the first dose of study treatment
8. Patient with history of solid organ or allogenic bone marrow transplantation