Intratumoral and Systemic Hiltonol® (Poly-ICLC) in Prostate Cancer Patients on Active Surveillance

114 prostate cancer participants on active surveillance will be randomized 2:1 into treatment group, A or control group B respectively. Enrolled group A study participants will receive standard of care (SOC) plus intratumoral (IT) and intramuscular (IM) injections of study drug Poly-ICLC (Hiltonol®) as follows: Preconditioning: week 1: Paired IM Poly-ICLC, 1.5 mg to reduce tumor induced suppression Immune Priming: week 2, intratumor poly-ICLC 1.0 mg once, Boosting: Wk. 3 - 10: Paired 1.5 mg IM poly-ICLC weekly Maintenance: Month 3-12, Paired IM Poly-ICLC once a month Control patients in group B will receive standard care (SOC) for patients on Active Surveillance per AUS guidelines. Comparisons of safety and efficacy will be based on data from concurrently randomized participants. An independent data and safety monitoring board (DSMB) will actively monitor interim data for safety, efficacy or futility. Seventy-six (76) participants will receive treatment IT/IM Poly-ICLC (Hiltonol®) and 38 participants will serve as controls for a total of 114 study participants. Participants randomized to the treatment arm will receive standard of care (SOC) plus IT/IM Poly-ICLC (Hiltonol®). Participants in the control arm will receive SOC. This is a partially blind randomized controlled phase 2 trial conducted at the Mount Sinai Health System with 114 participants planned for enrollment. Eligible participants will be randomly assigned to one of the two groups. There will be an interim analysis conducted after half of the participants, 38 receiving Poly-ICLC and 19 controls receiving standard care have completed 1 year of treatment.