Study of RP2 in Combination With Second-line Therapy in Patients With Locally Advanced Unresectable or Metastatic HCC

Open to people ages 18 years and up

Patient Population For the purposes of this clinical study, "enrolled/enrollment" means that patients, or their legally acceptable representatives', agree to participate in the study following completion of the informed consent process, confirmation of eligibility, and attendance at a Week 1 Day 1 Visit.

Inclusion criteria:

I 1. Male or female ≥ 18 years of age. I 2. Has locally advanced unresectable, recurrent, and/or metastatic HCC, with the diagnosis confirmed by histologic or cytologic analysis or clinical features or imaging criteria (using LI RADS v2018) according to the American Association for the Study of Liver Diseases criteria for patients with cirrhosis. Sites should select lesions that are either "probable HCC - LIRADS 4" or "definite HCC - LIRADS 5".

I 3. Must have progressed while on first and only systemic therapy, which must have included anti PD-1 or anti-PD-L1 therapy (eg, atezolizumab plus bevacizumab combination, durvalumab plus tremelimumab combination, durvalumab, pembrolizumab, or nivolumab monotherapy or nivolumab in combination with ipilimumab) as their immediate prior treatment regimen.

I 4. Child-Pugh A, determined within 14 days before first study treatment. I 5. Has at least 1 measurable tumor of ≥ 1 cm in longest diameter (or ≥ 1.5 cm shortest diameter for lymph nodes) as defined by RECIST 1.1.

I 6. Has injectable tumor(s), which alone or in aggregate, total at least 1 cm in diameter.

I 7. Must be willing to consent to provide fresh tumor biopsy sample or archival tumor biopsy sample obtained within 90 days before the first dose of study treatment.

I 8. Has adequate hematologic function, including:

• White blood cell (WBC) count ≥ 2.0 × 109/L
• Absolute neutrophil count (ANC) ≥ 1.5 × 109/L (without granulocyte-colony stimulating factor support)
• Platelet count ≥ 50 × 109/L (without transfusion)
• Hemoglobin ≥ 8.5 g/dL (may have received transfusions; however, patient must not be transfusion-dependent).

I 9. Has adequate hepatic function including:

• Total bilirubin ≤ 3.0 × upper limit of normal (ULN)
• Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) ≤ 5.0 × ULN.

I 10. Has adequate renal function, defined as serum creatinine ≤ 1.5 × ULN or creatinine clearance ≥ 30 mL/minute (measured using Cockcroft-Gault formula).

I 11. Serum albumin ≥ 2.8 g/dL. I 12. Prothrombin time (PT) ≤ 1.5 × ULN (or international normalization ratio [INR] ≤ 1.7) and partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT) ≤ 1.5 × ULN.

Note: Patients who are on a stable dose of long-term coumadin therapy may be enrolled if the target INR is ≤ 2.5, provided that the INR can be safely reversed to ≤ 1.7 temporarily around the time of RP2 injection.

I 13. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1. I 14. Women of childbearing potential and men of reproductive potential must agree to avoid becoming pregnant or impregnating a partner, respectively, and adhere to highly effective contraception requirements after signing informed consent, during the treatment period and for at least (a) 90 days after the last dose of RP2 or (b) 5 months after the last dose of atezolizumab or (c) 6 months after the last dose of bevacizumab, whichever is longer. Men must also agree to refrain from donating sperm during the treatment period and for at least 90 days after the last dose of RP2.

I 15. Women of childbearing potential must have a negative serum beta human chorionic gonadotropin (β-hCG) test with a minimum sensitivity of 25 IU/L or equivalent units of β hCG within 72 hours before the first dose and a negative urine pregnancy test on Dose 1 Day 1.

I 16. Capable of giving signed informed consent which includes willingness to comply with the requirements and restrictions listed in the informed consent form and in this protocol.

E 1. Child-Pugh B or C. E 2. Patients with untreated or incompletely treated esophageal and/or gastric varices with bleeding or high-risk for bleeding.

Note: All patients must undergo an esophagogastroduodenoscopy, and all varices (irrespective of size) must be assessed and treated per local standards of care before enrollment. Patients who have undergone endoscopic management of all known varices 120 days before initiation of study treatment do not need to repeat the procedure.

E 3. Significant bleeding event within the last 12 months that places the patient at unjustifiable risk for bleeding from intratumoral injection procedures, based on Investigator or interventional radiologist assessment.

E 4. Macroscopic intravascular invasion into the hepatic and/or segmental portal vein(s), hepatic vein, vena cava, and/or other major blood vessel, or into the hepatic and/or common bile duct(s).

E 5. Histologic evidence of fibrolamellar HCC, sarcomatoid HCC, or mixed cholangiocarcinoma with HCC, or other rare HCC variants.

E 6. History of medically refractory hepatic encephalopathy and/or hepato-renal syndrome.

E 7. Disease that is amenable to curative surgical and/or locoregional therapies.

E 8. Presence of liver tumors that are estimated to invade more than one-third of the liver.

E 9. Uncontrollable pleural effusion, pericardial effusion, or ascites requiring drainage within 7 days before enrollment.

E 10. Known acute or chronic hepatitis B (defined as hepatitis B surface antigen [HBsAg] reactive) or known acute or chronic hepatitis C virus (defined as HCV RNA [qualitative] is detected).

Note 1: If a site does not have qualitative HCV RNA testing, they may use quantitative HCV RNA testing (preferred) or qualitative HCV antibody detection.

Note 2: For patients with known acute or chronic HBV and/or HCV infection, HBV and/or HCV viral load by real-time polymerase chain reaction (qPCR) must be below the limit of quantitation for the laboratory test used, and they must not have had recent treatment within 12 weeks for HBV or HCV with antiviral medications. Patients with acute or chronic HBV or HCV must be expected to not require antiviral therapy during the RP2 treatment period.

E 11. Known human immunodeficiency virus (HIV) infection. Note: Testing for HIV is not required unless mandated by local health authority or clinically indicated.

E 12. Active significant herpetic infections or prior complications of HSV-1 infection (eg, herpetic keratitis or encephalitis) or requires intermittent or chronic use of systemic (oral or IV) antivirals with known antiherpetic activity (eg, acyclovir).

Note: Patients with sporadic cold sores may be enrolled if no active cold sores are present at the time of Dose 1 Day 1.

E 13. Systemic infection requiring IV antibiotics or other serious infection within 14 days before dosing.

E 14. Received a live vaccine within 28 days before the first dose of study treatment.

E 15. Known central nervous system (CNS) metastases and/or carcinomatous meningitis.

E 16. Prior malignancy, other than HCC, active within the previous 3 years, except for localized cancers that have apparently been cured including basal or squamous cell skin cancer, superficial bladder cancer, or carcinoma in situ of the prostate, cervix, or breast.

E 17. Is currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks before the first dose of study treatment.

Note: Patients who have entered the follow-up phase of an investigational study may participate if it has been 4 weeks after the last dose of the previous investigational agent.

E 18. Systemic anticancer therapies within 4 weeks of the first dose of study drug. The prior anti- PD- 1 or anti-PD-L1 containing regimen is excluded from this requirement.

Note: Patients must have recovered (to Grade ≤ 1 or baseline) from all AEs due to previous therapies. Patients with Grade ≤ 2 neuropathy may be eligible if approved by the Medical Monitor.

E 19. Received radiotherapy within 2 weeks of start of study treatment. Patients must have recovered from all radiation-related toxicities (except for radiation-induced xerostomia), not require corticosteroids, and not have had radiation pneumonitis. A 1-week washout is permitted for palliative radiation (≤ 2 weeks of radiotherapy) to non-CNS disease.

E 20. Received prior treatment with an oncolytic virus therapy. E 21. History of significant cardiac disease including myocarditis or congestive heart failure (defined as New York Heart Association Functional Classification III or IV), or unstable angina, serious uncontrolled cardiac arrhythmia, or myocardial infarction within 6 months of enrollment.

E 22. Uncontrolled infection. E 23. History of interstitial lung disease, idiopathic pulmonary fibrosis, organizing pneumonia (eg, bronchiolitis obliterans), non-infectious pneumonitis that required steroids, drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of active pneumonitis on screening chest CT scan.

Note: History of radiation pneumonitis in the radiation field (fibrosis) is permitted.

E 24. Active tuberculosis. E 25. History or evidence of psychiatric, substance abuse, or any other clinically significant disorder, condition, or disease (except for those outlined above) that, in the opinion of the Investigator or the Medical Monitor, would pose a risk to patient safety or interfere with the study evaluation, procedures, or completion.

E 26. History or current evidence of any condition, therapy, or laboratory abnormality that might confound the results of the study, interfere with the patient's participation for the full duration of the study, or is not in the best interest of the patient to participate, in the opinion of the Investigator.

E 27. Active, known, or suspected autoimmune disease requiring systemic treatment.

Note: Patients with type 1 diabetes mellitus and/or hypothyroidism requiring only hormone replacement, and/or with autoimmune skin disorders (such as vitiligo, psoriasis, or alopecia) not requiring systemic treatment, and/or prior non-serious autoimmune conditions not expected to recur are permitted to enroll.

E 28. Conditions requiring treatment with immunosuppressive doses (> 10 mg per day of prednisone or equivalent) of systemic corticosteroids within 14 days before Dose 1 Day 1.

Note: Patients who require a brief course (≤ 7 days) of corticosteroids (eg, as prophylaxis for imaging studies due to hypersensitivity to contrast agents) are not excluded. Physiologic replacement doses of systemic corticosteroids are permitted, only if the dose does not exceed 10 mg/day prednisone equivalent.

E 29. History of allergy or sensitivity to study drug components or prior monoclonal antibody treatment; known hypersensitivity to Chinese hamster ovary cell products or to any component of the atezolizumab or bevacizumab formulation.

E 30. History of life-threatening toxicity related to prior immune therapy (eg, anti-cytotoxic T lymphocyte antigen 4 or anti-PD-1/anti-PD-L1 treatment or any other antibody or drug specifically targeting T-cell co-stimulation or immune checkpoint pathways [eg, CD40, 4 1BB]) except those that are unlikely to recur or are expected to be manageable with standard countermeasures (eg, hormone replacement after adrenal crisis). Individual cases should be discussed with Medical Monitor if needed.

E 31. Conditions in which anticoagulant therapies cannot be safely stopped in the periprocedural period or patients on coumadin with a target INR > 2.5 or that cannot be temporarily reversed to INR ≤ 1.7.

E 32. Treatment with botanical preparations (eg, herbal supplements or traditional Chinese medicines) intended for general health support or to treat the disease under study within 2 weeks before treatment.

E 33. Prior organ transplantation including allogeneic stem-cell transplantation.

E 34. Major surgery within 28 days before starting bevacizumab or anticipated major surgery while on study.

Note: If a patient received major surgery, they must have recovered adequately from the intervention before starting study treatment and must have adequate wound healing, based on Investigator's assessment or surgeon's assessment, before starting bevacizumab.