Inclusion Criteria:

          1. Patients with Stage III/IV NSCLC on treatment with anti-PD-1/PD-L1 (ICI) +/-
             chemotherapy and a) have persistent but stable disease at least 18 weeks after
             starting ICI treatment, b) have radiographic progressive disease at least 18 weeks
             after starting ICI treatment, or c) have refractory disease defined as progressed by
             imaging at least 9 weeks after starting ICI treatment

          2. Measurable disease including a lesion that is amenable to injection

          3. Able and willing to undergo a pre-treatment and on-treatment biopsy

          4. ECOG Performance status of 0 or 1

          5. 18 years of age or older

          6. Granulocyte count (ANC) ≥ 1,000/mm3

          7. Peripheral lymphocyte count ≥ 500/mm3

          8. Hemoglobin ≥ 8 g/dl (patients may be transfused to meet this criterion)

          9. Platelets ≥ 75,000/mm3

         10. Total bilirubin ≤ 1.5 x upper limit of normal, except for patients with known Gilbert
             disease who must have total bilirubin ≤ 3 x upper limit of normal

         11. SGOT (AST) ≤ 5x upper limit of normal and if elevated, not clinically significant such
             that ICI can continue

         12. INR/aPTT within normal limits or, if on anti-coagulation, it must be clinically
             acceptable to hold anti-coagulation for the injection procedures as appropriate

         13. Serum creatinine < 2mg/dl and calculated creatinine clearance > 30ml/min

         14. Clinically eligible and willing to continue ICI

         15. Patients must give study specific informed consent prior to enrollment

        Exclusion Criteria:

          1. Patients with a history of severe hypersensitivity reaction to ICI

          2. Patients who require ongoing therapy with systemic immunosuppressive drugs including
             systemic corticosteroids (>10 mg prednisone per day or equivalent) - premedication for
             ICI or chemotherapy is allowed

          3. Patients with a history of active autoimmune disease requiring treatment in the past 2
             years

          4. Patients with uncontrolled intercurrent illness including, but not limited to, ongoing
             or active infection, symptomatic congestive heart failure, unstable angina pectoris,
             cardiac arrhythmia, active hepatitis, or psychiatric illness/social situations that
             would limit compliance with study requirements

          5. Women who are pregnant, lactating or intend to become pregnant during the study

          6. Patients who are known to be HIV positive

          7. Patients with a history of hypersensitivity or allergic reactions to valacyclovir or
             acyclovir

          8. Patients with significant heart disease (New York Heart Association Functional
             Classification III or IV)

          9. Patients with oxygen dependence (daily use)

         10. Tumor impinging on a neurovascular structure such that inflammation in the site may
             put patient at risk of compromise as determined by the investigator