Glioblastoma (GBM) prognosis remains dismal with a median survival of 16-18 months despite the use of multimodality treatment. Immunotherapy attempts have been unsuccessful in GBM treatment, including negative phase III trials of immune checkpoint inhibitors and vaccines. Based on strong preclinical data, we hypothesize that we can develop an effective immunotherapy approach against GBM by employing an immunostimulatory measles virus strain (MV-s-NAP) expressing the Helicobacter Pylori neutrophil-activating protein (NAP), a toll-like receptor 2 agonist. We also hypothesize that MV-s-NAP induced changes in the tumor microenvironment, resulting from immunogenic cell death, can increase efficacy and lead in synergy when combined with immune checkpoint inhibitors. We propose to further enhance the efficacy of this approach by blocking the inhibitory effect of IDO upregulation. We also propose to optimize viral replication in glioblastoma by blocking the interferon response pathway, a known mechanism of mammalian cell resistance to oncolytic viruses, with JAK inhibitors. This project has three specific aims:
In specific aim 1, we plan to evaluate the efficacy, optimal sequence and mechanism of action of MV-s-NAP virotherapy in conjunction with antibody blockade of the PD-1/PD-L1 axis and IDO inhibitors in immunocompetent GBM models, including GL261, CT2A, as well as genetically engineered models of spontaneous gliomagenesis.
In specific aim 2 we will evaluate the impact of modulating expression of interferon stimulated genes on the efficacy of MV-s-NAP virotherapy and immunovirotherapy by inhibiting the interferon response pathway, which has been shown to decrease viral permissiveness and replication.
In specific aim 3 we will test the safety of the optimal efficacy approach identified in specific aims 1 and 2 by conducting toxicology and biodistribution studies in measles replication permissive Ifnarko CD46 Ge mice (an FDA approved model of measles virus replication) in order to determine the safe dose of the combination prior to clinical translation. Safety of the recommended human dose will be further confirmed in a second primate (Rhesus macaques) model. Overall, this work will introduce an innovative multipronged immunovirotherapy approach in the treatment of glioblastoma that has the potential to overcome the lack of efficacy observed with other strategies.
/Lay Summary Although immuno-oncology approaches have benefitted many cancer patients, immunotherapy approaches for glioblastoma (GBM) have failed to demonstrate clinical benefit. Based on promising preclinical and early clinical data, we propose the use of an oncolytic virus strain armed with an immunostimulatory gene, the toll- like receptor 2 agonist NAP, as a novel antitumor approach against GBM that can enhance immunotherapeutic efficacy and result in synergy when combined with immune checkpoint inhibitors. We also propose to further increase activity by using IDO and JAK inhibitors in order to address a common mechanism of resistance to immune checkpoint inhibitors and enhance viral replication, prior to comprehensively testing both the efficacy and safety of this multipronged strategy on a path to clinical translation.
