T cells directed against mutant neo-epitopes drive cancer immunity. However, spontaneous immune recognition of mutations is inefficient. We recently introduced the concept of individualized mutanome vaccines and implemented an RNA-based poly-neo-epitope approach to mobilize immunity against a spectrum of cancer mutations. Here we report the first-in-human application of this concept in melanoma. We set up a process comprising comprehensive identification of individual mutations, computational prediction of neo-epitopes, and design and manufacturing of a vaccine unique for each patient. All patients developed T cell responses against multiple vaccine neo-epitopes at up to high single-digit percentages. Vaccine-induced T cell infiltration and neo-epitope-specific killing of autologous tumour cells were shown in post-vaccination resected metastases from two patients. The cumulative rate of metastatic events was highly significantly reduced after the start of vaccination, resulting in a sustained progression-free survival. Two of the five patients with metastatic disease experienced vaccine-related objective responses. One of these patients had a late relapse owing to outgrowth of β2-microglobulin-deficient melanoma cells as an acquired resistance mechanism. A third patient developed a complete response to vaccination in combination with PD-1 blockade therapy. Our study demonstrates that individual mutations can be exploited, thereby opening a path to personalized immunotherapy for patients with cancer.

NK cells treated with a cocktail of IL-12, IL-15, and IL-18 persist with sustained effector function in vivo and enhance tumor immunotherapy.

Natural killer (NK) cell infusions can induce remissions in subsets of patients with different types of cancer. The optimal strategies for NK cell activation prior to infusion are still under debate. There is recent evidence that NK cells can acquire long-term functional competence by preactivation with the cytokines IL-12/15/18. The mechanisms supporting the maintenance of long-term NK cell antitumor activity are incompletely understood. Here, we show that NK cells preactivated in vitro with IL-12/15/18, but not with IL-15 alone, maintained high antitumor activity even 1 mo after transfer into lymphopenic RAG-2The NK cell intrinsic ability for IFNg production coincided with demethylation of the conserved non-coding sequence (CNS) 1 in the Ifng locus, previously shown to enhance transcription of Ifng. In a xenograft melanoma mouse model, human IL-12/15/18-preactivated NK cells rejected tumors more efficiently. In RAG-2C T cells further improved the long-term competence of NK cells for IFNg production that was dependent on IL-2. CD4C T cell activation during homeostatic proliferation required macrophages and further promoted the long-term NK cell antitumor activity. Thus, NK cells can "remember" a previous exposure to cytokines by epigenetic imprinting resulting in a remarkable stability of the IFNg-producing phenotype after adoptive transfer. In addition, our results support combination of cytokine-preactivated NK cells with CD4 C T cell activation upon lymphopenic conditioning to achieve long-term NK cell effector function for cancer immunotherapy.