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The tumor-intrinsic NOD-, LRR- and pyrin domain-containing protein-3 (NLRP3) inflammasome–heat shock protein 70 (HSP70) signaling axis is triggered by CD8 + T cell cytotoxicity and contributes to the development of adaptive resistance to anti–programmed cell death protein 1 (PD-1) immunotherapy by recruiting granulocytic polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) into the tumor microenvironment. Here, we demonstrate that the tumor NLRP3-HSP70 axis also drives the accumulation of PMN-MDSCs into distant lung tissues in a manner that depends on lung epithelial cell Toll-like receptor 4 (TLR4) signaling, establishing a premetastatic niche that supports disease hyperprogression in response to anti–PD-1 immunotherapy. Lung epithelial HSP70-TLR4 signaling induces the downstream Wnt5a-dependent release of granulocyte colony-stimulating factor (G-CSF) and C-X-C motif chemokine ligand 5 (CXCL5), thus promoting myeloid granulopoiesis and recruitment of PMN-MDSCs into pulmonary tissues. Treatment with anti–PD-1 immunotherapy enhanced the activation of this pathway through immunologic pressure and drove disease progression in the setting of Nlrp3 amplification. Genetic and pharmacologic inhibition of NLRP3 and HSP70 blocked PMN-MDSC accumulation in the lung in response to anti–PD-1 therapy and suppressed metastatic progression in preclinical models of melanoma and breast cancer. Elevated baseline concentrations of plasma HSP70 and evidence of NLRP3 signaling activity in tumor tissue specimens correlated with the development of disease hyperprogression and inferior survival in patients with stage IV melanoma undergoing anti–PD-1 immunotherapy. Together, this work describes a pathogenic mechanism underlying the phenomenon of disease hyperprogression in melanoma and offers candidate targets and markers capable of improving the management of patients with melanoma.

Use of comprehensive genomic profiling (CGP) in metastatic colorectal cancer (mCRC) is limited. We estimated impacts of expanded 1 L CGP, using the Tempus xT test, on detection of actionable alterations and testing budgets in a modeled US health plan over two-years. A decision analytic model was developed to estimate the impact of replacing 20% of usual testing (a mix of CGP and non-CGP) with Tempus xT CGP. Actionable alterations for matched treatments or clinical trial included KRAS, NRAS, RAF, BRAF, deficient mismatch repair (dMMR)/microsatellite instability (MSI), NTRK, RET, EGFR, HER2, MET, PIK3CA and POLE1. Costs included initial and repeat testing, physician-associated and administrative costs. In a hypothetical five-million-member plan, 50% Medicare and 50% commercial, 1,112 new cases of mCRC were expected per year. Of these, 566 (51%) would undergo 1 L molecular testing, with 55 re-tested upon progression. Based on current testing rates, there were an expected 521 missed opportunities for genomically informed treatment (47% of new cases), with 442 missed due to lack of testing and 79 due to testing without CGP. Replacing 20% of usual testing with Tempus xT CGP was associated with up to a $0.003 per member per month testing cost increase (net total cost of $202,102 for the five-million-member plan) and 15.5 additional patients with an opportunity for genomically informed care (12.7 patients for treatment and 2.8 for clinical trial). The testing total cost (initial test, repeat test, biopsy and physician services, and administrative cost) to put one additional patient with mCRC on matched therapy or matched clinical trial was estimated to be $13,005. Number needed to test to identify one actionable alteration with Tempus xT CGP versus usual testing was 7.8 patients. Conservative assumptions were made for inputs with limited evidence. Based on high concordance rates with dMMR/MSI status, tumor mutational burden (TMB) status was not calculated separately. Replacing 20% of usual testing with Tempus xT CGP was associated with a small incremental testing cost and can identify meaningfully more actionable alterations.

The mechanisms underlying tumor immunosurveillance and their association with the immune-related adverse events (irAEs) associated with checkpoint inhibitor immunotherapies remain poorly understood. We describe a metastatic melanoma patient exhibiting multiple episodes of spontaneous disease regression followed by the development of several irAEs during the course of anti-programmed cell death protein 1 antibody immunotherapy. Whole-exome next-generation sequencing studies revealed this patient to harbor a pyrin inflammasome variant previously described to be associated with an atypical presentation of familial Mediterranean fever. This work highlights a potential role for inflammasomes in the regulation of tumor immunosurveillance and the pathogenesis of irAEs.

3053 Background: Activation of the Wnt-β-catenin signaling pathway is associated with poor T cell infiltration of tumors. We have previously demonstrated that paracrine Wnt5a-β-catenin signaling is a critical trigger of dendritic cell (DC) tolerization and regulatory T cell (Treg) differentiation in the melanoma microenvironment. In a transgenic BRAFV600EPTEN-/- model, the genetic silencing of melanoma-derived Wnt5a potently enhances infiltrating CD8+T cell effector function and promotes responses to anti-PD-1 Ab therapy. Ipafricept (IPA) is a recombinant Wnt decoy receptor and Vantictumab (VAN) is a Fzd receptor monoclonal Ab. Both molecules inhibit Wnt-β-catenin signaling and have been well-tolerated in ongoing phase I/Ib clinical trials. We explored the ability of IPA/VAN to reverse tumor-mediated immune tolerance and enhance the efficacy of anti-PD-1 Ab immunotherapy in a pre-clinical model that closely recapitulates human melanoma. Methods: Both IPA and VAN were utilized to investigate Wnt-β-catenin inhibition as a strategy for suppressing melanoma-induced DC indoleamine 2,3-dioxygenase (IDO) expression and Treg differentiation in vitro. These agents were further tested for their ability to enhance anti-tumor T cell responses and to augment the efficacy of anti-PD-1 Ab therapy in syngeneic and autochthonous models of BRAFV600EPTEN-/- melanoma. Results: IPA and VAN effectively inhibit Wnt5a and melanoma-induced DC IDO expression and Treg differentiation in vitro. Further studies demonstrate that IPA and VAN significantly augment anti-PD-1 Ab-mediated suppression of primary and metastatic tumor progression in both syngeneic and autochthonous BRAFV600EPTEN-/- melanoma models. These anti-tumor effects correlated with suppressed IDO enzymatic activity, enhanced tumor-infiltrating CD8+T cell/Treg ratios, and increased activation of TRP2 antigen-specific effector T cells. Conclusions: The pharmacological inhibition of paracrine Wnt-β-catenin signaling with IPA and VAN augment the anti-tumor efficacy of anti-PD-1 Ab therapy and represent a promising strategy for further phase I testing in melanoma and other solid tumors.

Pancreatic cancer is one of the more difficult malignancies to treat, and there is a great need for less toxic, effective regimens. Immunotherapy has shown potential in the treatment of pancreatic cancer, and at ASCO 2013 there were several progressive advances in its clinical application. Abstracts #3067, #3049, #3007, #4040, #LBA4004, and #3090 will be discussed. New developments in the field of immunotherapy are promising novel treatments for pancreatic neoplasms with tolerable side effect profiles., JOP. Journal of the Pancreas, Vol 14, N° 4 (2013): July - p. 304-474

e14581 Background: The cancer stem cell (CSC) hypothesis of tumorigenesis suggests that unlike most cancer cells within a tumor CSC resist chemotherapy and can regenerate various cell types in tumo...