Eight patients remain tumor-free one year after treatment. pro-inflammatory cytokines such as GM-CSF or IL-12 (5-7). CpG, a ligand of TLR-9 and poly I:C, a TLR-3 ligand, are among the most potent TLR ligands in malignancy immunotherapy (8,9). Interestingly, synergistic combinations of different TLRs have been found and novel molecular pattern receptors such KHS101 hydrochloride as the STING pathway widen the druggable pathways (10). Another strategy to activate the molecular pattern receptors is the use of viral and non-viral gene therapy vectors. These vectors are able to induce the release of tumor antigens in the context of immunogenic cell death. Gene therapy vectors encoding pro-inflammatory cytokines are able to induce an immune response against several tumoral antigens, avoiding the need for tumor-associated antigen identification (5,6,11,12). Finally, the combination of antigen delivery KHS101 hydrochloride and antigen presenting cell maturation can be achieved with Rabbit polyclonal to P4HA3 protein vectors that target dendritic cells (6,9). We have demonstrated that this eradication of large tumors in mice can be achieved with a combined treatment. The treatment must include a drug to provide danger signals to the innate immune system. In our hands, the best drugs are polyI:C, a TLR3 ligand, and CpGs, a TLR9 ligand. Second of all, the treatment must include a vaccine. We have demonstrated potent antitumor efficacy with vaccines based on a detoxified version of the adenylate cyclase of and with a fragment of the extracellular domain name of fibronectin. The third component of a vaccine must keep in check the main regulatory immune system that blocks the antitumor activity of immune effector cells. In mouse models, a single low dose of cyclophosphamide is extremely potent due to the combination of T regulatory cell removal and remodeling of the tumor-associated myeloid cells (9,13). Lessons from clinical trials in melanoma In 2004, Rosenberg published a review of all the clinical trials that they performed at NHI to test antitumor vaccines in melanoma. The clinical experience included different adjuvants KHS101 hydrochloride and delivery vehicles such as viruses, proteins, and peptides. The antigens assayed covered a broad spectrum of tumor-associated antigens. Their objective response rate was as low as 2.6% (14). Since then, several anti-melanoma vaccines have been tested in phase III clinical trials for the treatment of advanced melanoma. However, none have been commercialized. The gp100 peptide was formulated with Montanide ISA-51 and combined with systemic interleukin-2. This vaccine was administered to 185 patients with locally advanced stage III and stage IV cutaneous melanoma. The median overall survival was 17.8 months with the vaccine compared with 11.1 months with interleukin-2 alone (P=0.06) (15,16). Gp100 was also tested in combination with ipilimumab, an antibody that blocks CTLA-4. The 3-12 months survival rate with ipilimumab alone was 25% and only 15% with the combination of gp100 and ipilimumab (16). Vitespen is an autologous vaccine composed of tumor-derived warmth shock proteins-peptide complexes. This vaccine was analyzed in a phase II clinical trial in stage IV melanoma patients. The overall survival in the vaccine treated patients was similar to that in patients treated with physicians choice (17). loading of dendritic cells with peptide has also been tested in a phase III clinical trial in metastatic melanoma. The vaccinated arm was compared with standard dacarbazine. No significant differences in the objective response were observed (18). The lack of efficacy of KHS101 hydrochloride these large clinical trials focused on traditional tumor-associated antigens has promoted the search for alternative strategies to elicit KHS101 hydrochloride an immune response. Personalized neoantigen-based vaccines High mutation burden has shown a strong correlation with the clinical benefit in checkpoint inhibitor therapy (PD-L1/PD-1 and CTLA-4) (19-21) and several studies have associated the efficacy of malignancy immunotherapy with the recognition of specific neoantigen by T cells in melanoma patients (22-24). Moreover,.