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Background: Survivin is a promising tumor-associated antigen for cancer immunotherapy that fulfills two major criteria for this purpose: (1) tumor cells depend on the actions of survivin (inhibition of apoptosis, unrestricted proliferation and angiogenesis); and (2) the protein has demonstrated immunogenicity in patients with different cancers. Here we report results of a first-in-man Phase I study with EMD640744, a cocktail of survivin-derived partially modified HLA class I-restricted peptides in Montanide® ISA 51 VG. Methods: This multicenter, open-label, parallel group, randomized study compared the immunologic efficacy, safety, tolerability and clinical activity of three dosages of EMD640744 (30, 100, or 300 µg) in patients with different types of metastatic or locally advanced solid tumors who were positive for at least one relevant HLA antigen (A1, A2, A3, A24, B7). Patients received weekly s.c. injections of EMD640744 for 8 weeks followed by injections every 4 weeks until tumor progression. For the assessment of the primary endpoint, PBMC samples were prepared at baseline and after 4, 8, 12, 16, and 17 weeks. Peptide-specific T cell responses were analyzed by IFN-γ ELISpot. As a secondary analysis, peptide/HLA-multimer staining was performed. Frequencies of CD8+ T cells specific for patient-relevant single HLA-restricted peptides and EMD640744 were determined ex vivo and after short-term in vitro presensitization with EMD640744. Native homologues of modified vaccination peptides were also included in the analysis. Results: Of 66 patients screened, 53 were treated, and a majority was eligible for response analysis: 38 patients were analyzed by ELISpot and 42 by multimers, with positive ex vivo responses observed in 7 (18%) and 14 (33%) patients, respectively. Combining ex vivo data with results after in vitro stimulation, T cell responses were detected in 14 (37%) and 31 (74%) patients by ELISpot and multimer analysis, respectively. Multimer staining revealed a de novo induction of T cells against survivin peptides in at least 16 patients (38%) whereas pre-existent responses were seen in only 4 patients (10%). T cell responses were detected in all dose groups with similar frequencies. Five out of 10 HLA-A2+ patients reacting against the modified A2-binding peptide in ELISpot assays showed responses against its native homologue. The best tumor response according to RECIST was stable disease in 28% of patients. The most frequent treatment-related adverse events (AEs) were Grade 1-2 local injection site reactions and 2 patients experienced treatment-related Grade 3 AEs (granuloma at injection site and thrombosis). Conclusion: Vaccination with EMD640744 was safe and well tolerated and elicited de novo T cell responses against survivin peptides, demonstrating immunological efficacy of EMD640744 in cancer patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5516. doi:10.1158/1538-7445.AM2011-5516

Although current allo-transplantation therapy can induce considerable graft-versus-tumor (GvT) effects in RCC patients, it is also accompanied by severe, even life-threatening side effects, mainly due to graft-versus-host disease (GvHD). Efforts aiming to improve the specificity and efficiency of allogeneic cell therapy in this disease (e.g. specific donor lymphocyte infusion or vaccination) will certainly benefit from the identification of potential anti-tumor effector mechanisms and their corresponding target structures. We recently demonstrated that RCC-reactive cytotoxic T-lymphocyte (CTL) clones can be isolated from peripheral blood of healthy donors matched with the RCC stimulators for HLA-class I. These CTL were found to recognize a broad panel of RCC antigens with restricted or ubiquitous tissue expression (Doerrschuck A, et al., Blood July 1, 2004, Epub). We now extended our analyses on peripheral blood mononuclear cells (PBMC) of further HLA-matched healthy sibling (1) and unrelated individuals (4) and compared these results with available autologous patient PBMC. While mixed lymphocyte/tumor-cell culture (MLTC) responders derived from allogeneic donors showed a robust antigen-dependent proliferation over several weeks, a weak if any proliferative response was seen with autologous MLTC populations. By analysing the fine specificity of MLTC-derived clonal CTL the majority of allogeneic effectors recognized exclusively their RCC stimulators, but not corresponding lymphoblastoid-cell lines or natural killer target K562. These CTL were restricted by various HLA-A, -B or -C molecules. We further isolated CTL clones that exhibit an extraordinary strong recognition of RCC and various epithelial tumor-cell lines. Antibody blocking experiments provided clear evidence that these CTL are restricted by a not yet defined HLA-Ib molecule and, simultaneously, by a NKG2D-dependent mechanism. Other rapidly proliferating CD3+ CD8+ CTL clones were obtained that showed a non-HLA-restricted reactivity against RCC and a minor but consistent reactivity against targets with low or absent HLA-class I expression (e.g. K562). In conclusion, our results demonstrate that a heterogeneous panel of RCC-reactive HLA-Ia/Ib-restricted CTL can be isolated from PBMC of HLA-class I-matched healthy individuals. Alternatively, CTL recognizing RCC in a non-HLA restricted manner can be obtained. Our observations might reflect the superior ability to activate and expand RCC-directed T cells from PBMC of allogeneic healthy donors compared to the autologous setting. At this point, we cannot conclude whether these various CTL populations contribute to effective anti-RCC immune responses occurring in vivo. Answering this question will certainly require to identify further CTL-defined target structures at the molecular level. This would allow us to analyse the expression of candidate antigens and the frequency of specific CTL in RCC patients after allogeneic blood stem-cell transplantation, and to correlate these findings with clinical GvT and GvH events.