Lymphatic delivery of immunotherapy to prevent irAEs

点击翻译按钮获取中文摘要

As higher vertebrates evolved from the sea into land dwellers and terrestrial antigen (Ag) exposure increased, the adaptive immune system evolved from a centralized system to one dependent upon regional draining lymph nodes (dLNs) that allow immune responses to multiple Ags while preserving central tolerance. Despite the importance of LNs initiating immune responses for systemic immunity/tolerance, checkpoint blockade immunotherapies (CBIs) are administered intravenously, often failing to reach the dLNs that are the sites of dysfunctional T cell priming responsible for tolerance to tumor Ags (tAgs). When administered systemically, these therapies act in an Ag-indiscriminate and system-wide fashion often breaching self-tolerance and leading to severe immune related adverse events (irAEs). We hypothesize that regional delivery of immunotherapies within the distinct lymphatic watersheds to dLNs will (i) enhance systemic immunity or tolerance and (ii) substantially reduce irAEs when compared to systemic delivery. Scientific justification for our hypothesis comes from our data in preclinical, orthotopic breast (4T1) and melanoma (B16F10) studies of cancer metastases. We show that lymphatic delivery of αCTLA-4 alone or in combination with αPD-1 (i) improves anti-tumor responses, (ii) results in complete responses not seen with systemic or i.v. administration, and/or (iii) ameliorates distant metastases in these otherwise non-immunogenic models. Preclinical and clinical studies using microneedle array devices and near-infrared fluorescence lymphatic imaging shows the technical ability to deliver drug specifically to regional lymph nodes. However, there has been no preclinical demonstration that lymphatic delivery will alleviate irAEs, due to the lack of a susceptible mouse model. Before further study of lymphatic delivery can be made or translated into cancer patients, the benefit of reduced irAEs needs to be demonstrated. Because irAEs limit combinational αCTLA-4/αPD-1 therapy and the more toxic, agonist α4-1BB CBIs, lymphatic delivery could provide a substantial breakthrough needed expand the use of CBIs to treat more cancer patients at earlier stages of disease. In this NCI Clinical and Translational Exploratory/Developmental R21 (PAR-20-292) project, we propose to use a well-characterized Foxp3-DTR mouse model of transient Treg depletion to provide a readout of irAEs from i.v. and lymphatically delivered CBIs. Our specific aims are to (1) characterize immunological consequences resulting from i.v. and lymphatic delivery of αCTLA-4/αPD-1 and α4-1BB in non-tumor bearing, C57BL/6 and Balb/C strains of Foxp3-DTR mice and to (2) compare anti-tumor immunity and readouts of immunological consequences from i.v. and lymphatic delivery of CBIs in 4T1 and B16F10 tumor bearing animals. In practice, clinical observations of irAEs are associated as early indication of CBI response. If successful, we will decouple irAEs from anti-tumor immunity and improve cancer treatments by changing the way we deliver immune modifying therapeutics.