Engineering Newcastle Disease Virus as an Oncolytic Vector for Intratumoral Delivery of Immune Checkpoint Inhibitors and Immunocytokines

Abstract

Newcastle disease virus (NDV) is an attractive candidate for oncolytic immunotherapy due to its ability to replicate in tumor cells and potentially to overcome the inherently immunosuppressive nature of the tumor microenvironment. The advent of checkpoint blockade immunotherapy over the past few years represents a paradigm shift in cancer therapy. However, the prevalence of severe immune-related adverse events with CTLA4 and PD1 pathway blockade in clinical studies, especially in combination therapy groups, is a cause for concern. Immunotherapies with cytokines have also been extensively explored, but they have been associated with adverse events in clinical trials. Oncolytic vectors engineered to express checkpoint blockade antibodies and cytokines could provide an avenue for reducing the clinical toxicity associated with systemic therapy by concentrating the immunomodulatory payload at the site of disease. In this study, we engineered six different recombinant viruses: NDVs expressing checkpoint inhibitors (rNDV–anti-PD1 and rNDV–anti-PDL1); superagonists (rNDV–anti-CD28); and immunocytokines, where the antibodies are fused to an immunostimulatory cytokine, such as interleukin 12 (IL-12) (rNDV–anti-CD28–murine IL-12 [mIL-12], rNDV–anti-PD1–mIL-12, and rNDV–anti-PDL1–mIL-12). These six engineered viruses induced tumor control and survival benefits in both highly aggressive unilateral and bilateral B16-F10 murine melanoma models, indicative of an abscopal effect. The data represent a strong proof of concept on which further clinical evaluation could build. IMPORTANCE Checkpoint inhibitor therapy has shown tremendous efficacy, but also frequent and often severe side effects—especially when multiple drugs of the class are used simultaneously. Similarly, many investigational immunotherapy agents, which have shown promise in animal models, have failed in clinical trials due to dose-limiting toxicity when administered systemically. This study utilized a murine melanoma model to evaluate the efficacy of intratumoral injections of recombinant NDVs engineered to express multiple immunotherapeutic proteins with well-documented side effects in humans. Our results indicate that intratumoral administration of these recombinant NDVs, particularly when combined with systemic CTLA4 checkpoint inhibition, exerts a robust effect in treated and nontreated tumors, indicative of a systemic antitumoral response. The intratumoral delivery of rNDVs expressing immunotherapeutic proteins may be an effective method of targeting the immune cell populations most relevant for antitumoral immunity and allowing us to restrict the use of systemic immunotherapy agents.

Localized Interleukin-12 for Cancer Immunotherapy

“…anti-CTLA-4 or NDV-antiPDL1-mIL-12 plus i.p. anti-CTLA-4 resulting in complete responses in 77 or 70%, respectively of mice bearing 9 day-old B16F10 flank tumors (277). The same treatments of one of two bilateral tumors resulted in 10 and 62% complete responses, respectively, of untreated tumors (277).…”

“…Newcastle disease virus (NDV) is an oncolytic, enveloped, negative-sense, single-stranded RNA virus. NDVs have been engineered to express checkpoint inhibitor molecules and checkpoint inhibitor-cytokine conjugates (277). Although the antitumor activity of i.t.…”

Closely related reovirus lab strains induce opposite expression of RIG-I/IFN-dependent versus -independent host genes, via mechanisms of slow replication versus polymorphisms in dsRNA binding σ3 respectively

“…Many studies have characterized immunological responses to oncolytic viruses and support immunotherapeutic value of tumor-specific viruses. To enhance the immunotherapeutic response, oncolytic viruses are being explored in combination with other immunomodulatory approaches such as cytokines and immune checkpoint inhibitors [ 13 , 14 ]. Given that oncolytic viruses were not adapted to trigger higher immune responses to begin with, is it surprising that their immune-activation activities are sub-par?…”

Newcastle Disease Virus as a Vaccine Vector for 20 Years: A Focus on Maternally Derived Antibody Interference

“…Vijayakumar and colleagues demonstrated that the recombinant NDV expressing the checkpoint inhibitor (anti-CTLA-4) worked together with radiotherapy to enhance tumor clearance of murine melanoma, indicating NDV is an effective immunotherapy agent capable of transgenic expression of single-chain variable fragment antibody in vivo to spare systematic exposure [ 96 ]. They also generated the recombinant NDVs expressing mAbs (PD1/PD-L1 antibody), superagonists (CD28) and immunocytokines (IL-12) and found that the viruses induced tumor control and survival benefits in a highly aggressive murine melanoma model [ 97 ]. These studies ingeniously combine two biological features of NDV, i.e., oncolytic activity and gene delivery capacity, together in immunotherapy for tumors, which further extends the range of clinical application of the NDV vector in human medicine.…”