CF33-hNIS-antiPDL1 for the Treatment of Metastatic Triple Negative Breast Cancer

PRIMARY OBJECTIVE: I. To determine the safety and tolerability of a novel chimeric oncolytic orthopoxvirus, oncolytic virus CF33-expressing hNIS/Anti-PD-L1 antibody (CF33-hNIS-antiPDL1), by the evaluation of toxicities including: type, frequency, severity, attribution, time course, reversibility and duration according to Common Terminology Criteria for Adverse Events (CTCAE) 5.0 criteria. SECONDARY OBJECTIVES: I. To determine the optimal biologic dose (OBD) (defined as a safe dose that induces an immune response in tumors \[increase checkpoint target PD-L1 by at least 5% and/or increase T cell infiltration by at least 10%\]) and the recommended phase II dose (RP2D) for future expansion trial. II. To determine tumor response rates by Response Evaluation Criteria in Solid Tumors (RECIST) version (v)1.1 (primary) and immune-modified (i)RECIST (secondary). III. To document possible therapeutic efficacy and evaluate progression-free survival, overall survival and response. EXPLORATORY OBJECTIVE: I. To determine the immune and genomic profiles of tumors before and after CF33-hNIS-antiPDL1 therapy. OUTLINE: This is a dose-escalation study. Patients receive CF33-hNIS-antiPDL1 intratumorally (IT) on days 1 and 15. Treatment repeats every 28 days for up to 3 cycles in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up at 30 days, then every 3 months for 1 year.