Short-course neoadjuvant in situ vaccination for murine melanoma

Abstract

BackgroundSurgical resection remains an important component of multimodality treatment for most solid tumors. Neoadjuvant immunotherapy has several potential advantages, including in-situ tumor vaccination and pathologic assessment of response in the surgical specimen. We previously described an in-situ tumor vaccination strategy in melanoma using local radiation (RT) and an intratumoral injection of tumor-specific anti-GD2 immunocytokine (IT-IC). Here we tested whether neoadjuvant in-situ tumor vaccination using anti-GD2 immunocytokine and surgical resection, without RT, could generate immunologic memory capable of preventing recurrence or distant metastasis.MethodsMice bearing GD2 expressing B78 melanoma tumors were treated with neoadjuvant radiation, IT-IC, or combined RT + IT-IC. Surgical resection was performed following neoadjuvant immunotherapy. Immune infiltrate was assessed in the resection specimens. Mice were rechallenged with either B78 contralateral flank tumors or pulmonary seeding of non-GD2 expressing B16 melanoma metastasis induced experimentally. Rejection of rechallenge in mice treated with the various treatment regimens was considered evidence of immunologic memory.ResultsNeoadjuvant IT-IC and surgical resection resulted in increased CD8 T cell infiltration, a higher CD8:regulatory T cell ratio, and immunologic memory against contralateral flank rechallenge. The timing of resection did not significantly impact the development of memory, which was present as early as the day of surgery. There was less local wound toxicity with neoadjuvant IT-IC compared with neoadjuvant RT +IT IC. Neoadjuvant IT-IC and resection resulted in the rejection of B16 lung metastasis in a CD4 T cell dependent manner.ConclusionsNeoadjuvant IT-IC generates immunologic memory capable of preventing distant metastasis despite limited efficacy against large primary melanoma tumors. By combining neoadjuvant tumor vaccination and surgery, the toxicity of local RT was avoided. These preclinical data support further investigation regarding the use of neoadjuvant IT-IC in patients with melanoma at high risk for occult distant disease.

Single cell metabolic imaging of tumor and immune cells in vivo in melanoma bearing mice

“…Combining our live, spatial imaging with additional assays such as metabolite measurements via mass spectrometry or radiolabel tracing of glucose should identify specific metabolic pathways and possible drug targets ( 88 – 91 ). There is also great potential to use this in vivo imaging platform to assess drug, and especially immunotherapy, treatments in vivo , work that we are currently pursuing ( 40 – 42 ). Future studies may include the analyses done here – in mice receiving immunotherapy regimens known to be effective compared to those from which tumors are resistant or escape – in combination with other analyses of immune cell function, phenotype, and gene expression to identify metabolic patterns characteristic of effective anti-tumor immunity.…”

“…B78 tumors were engrafted by intradermal flank injection of 2×10 6 tumor cells (39). We have previously developed successful immunotherapy regimens for mice bearing these B78 tumors, enabling the cure of mice with measurable tumors (~100 mm 3 volume) (40)(41)(42). These cured mice have demonstrated tumor-specific T-cell mediated memory, as detected by rejection of rechallenge with the same vs. immunologically distinct tumors.…”

Local delivery of low-dose anti–CTLA-4 to the melanoma lymphatic basin leads to systemic T reg reduction and effector T cell activation

“…By local administration of immune checkpoint inhibitors in or around the primary tumor, high concentrations and bioavailability of these drugs in the tumor and TDLN can be reached, allowing for priming of effector and memory T cells while minimizing actual systemic exposure and subsequent toxicity (15,33,(46)(47)(48). Although the concept of intratumoral immunomodulation and/or ablation to achieve in vivo vaccination has long been proposed and pursued (46,(49)(50)(51)(52), there are very few clinical studies that have explored the effects of local delivery of immune checkpoint inhibitors (NCT03889912, NCT03316274, NCT04090775, and NCT03755739).…”

Alum-anchored intratumoral retention improves the tolerability and antitumor efficacy of type I interferon therapies

“…Local delivery enables high cytokine concentration at the tumor initially, but unanchored proteins can rapidly leak out ( 31 ). Strategies that afford some retention to locally injected cytokines include tethering to the extracellular matrix ( 21 , 23 , 31 , 64 ), cellular targets ( 65 – 67 ), or various biomaterials ( 68 – 70 ). Of note, we recently enabled particularly long-term intratumoral retention for weeks by using the FDA-approved material alum, which forms intratumoral depots and serves as an anchor for alum-binding cytokines ( 22 ).…”