This renewal application addresses the critical issue of treating metastatic cancer by combining three potent anti-cancer modalities: therapeutic ultrasound, chemotherapy and immune agonists. The enhanced accumulation (~25% ID/cc) and transport surrounding an ultrasonically-ablated region is shown to be far greater than that achieved with mild hyperthermia and is consistent across varied tumor biology. Further, the creation of small regions of ablation greatly enhances transport of tumor antigen into the draining lymph nodes and enhances systemic immune response. Through a collaboration with Image Guided Therapy, we have developed a flexible system to precisely control ultrasound therapy. Here, we will scale up our therapeutic ultrasound system from a 16-element annular array to a 256-element phased array for translation and develop the capability to model the thermal dose created by ultrasound. We will incorporate nonlinear modeling of propagation to predict lesion formation. Further, we will create protocols that combine ultrasound biological effects with chemotherapy and/or immune agonists in a systematic fashion. While cryoablation has been shown to be synergistic with immune agonists, ultrasound has far greater potential since insonation greatly improves drug delivery and transport; yet, this combination has yet to be explored. Our preliminary results and publications demonstrate the following: 1) by combining long circulating nanoparticles with ultrasound, we increase the fraction of therapeutic dose within primary tumors and the draining lymph nodes while decreasing systemic toxicity and avoiding leukopenia, 2) ultrasound ablation enhances the local CD8+ T cell population and dendritic and NK cell populations and 3) ultrasound combined with immune agonists increases local and systemic anticancer immunity, resulting in enhanced CD8+ T cell populations in treated and untreated tumors.
Our specific aims are to: scale up our technology in order to translate the resulting combination to larger animal models as the final step toward human translation; conduct studies of systemic nanoparticle chemotherapy combined with US to eliminate primary tumors in rodents and canines, and combine immunomodulatory agents with chemotherapeutics and ablation to create a systemic anticancer effect and treat metastatic cancer.
We have demonstrated that ultrasound-enhanced delivery can be effective in treating primary cancers and here propose to extend these studies to larger animals using a scaled up therapeutic ultrasound system and to extend these studies to metastatic cancer by activation of the immune system.
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