Survivin Peptides Research Articles

Abstract A074: Maveropepimut-S, a DPX-based immune-educating therapy, combined with Pembrolizumab and Cyclophosphamide in recurrent ovarian cancer, results from the Phase 1/2 PESCO Trial

Abstract A074: Maveropepimut-S, a DPX-based immune-educating therapy, combined with Pembrolizumab and Cyclophosphamide in recurrent ovarian cancer, results from the Phase 1/2 PESCO Trial

PD-L1 expression predicts efficacy in the phase II SPiReL trial with MVP-S, pembrolizumab, and low-dose CPA in R/R DLBCL.

Patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) have limited treatment options. R/R DLBCL patients, who were mostly ineligible for ASCT due to age or comorbidities, were treated with maveropepimut-S (MVP-S, previously DPX-Survivac) a survivin directed T cell educating therapy, pembrolizumab, and intermittent low-dose cyclophosphamide. We identified, using univariate analysis, a subset of patients with enhanced ORR, PFS and DOR. Patients with baseline CD20+/PD-L1 expression had an ORR of 46% (6/13) and the disease control rate was 10/13 (77%). The PFS and OS of the positive CD20+/PD-L1 patients were 7.1 months and 17.4 months, whereas in the intent-to-treat (ITT) population of 25 enrolled patients, the ORR was 28% (7/25), median PFS and OS were 4.2 months and 10.1 months respectively. A total of 6/7 clinical responders occurred in CD20+/PD-L1 patients. The regimen was well-tolerated, requiring only minor dose modifications and one discontinuation. Grade 1 or 2 injection site reactions occurred in 14/25, (56%). Statistically significant associations were also seen between PFS and; injection site reactions; and ELISpot response to survivin peptides, both identifying the mechanistic importance of specific immune responses to survivin. This immunotherapy combination was found to be active and safe in this clinically challenging patient population.

Survivin (BIRC5) Peptide Vaccine in the 4T1 Murine Mammary Tumor Model: A Potential Neoadjuvant T Cell Immunotherapy for Triple Negative Breast Cancer: A Preliminary Study

A triple negative breast cancer model using the murine 4T1 tumor cell line was used to explore the efficacy of an adjuvanted survivin peptide microparticle vaccine using tumor growth as the outcome metric. We first performed tumor cell dose titration studies to determine a tumor cell dose that resulted in sufficient tumor takes but allowed multiple serial measurements of tumor volumes, yet with minimal morbidity/mortality within the study period. Later, in a second cohort of mice, the survivin peptide microparticle vaccine was administered via intraperitoneal injection at the study start with a second dose given 14 days later. An orthotopic injection of 4T1 cells into the mammary tissue was performed on the same day as the administration of the second vaccine dose. The mice were followed for up to 41 days with subcutaneous measurements of tumor volume made every 3-4 days. Vaccination with survivin peptides was associated with a peptide antigen-specific gamma interferon enzyme-linked immunosorbent spot response in the murine splenocyte population but was absent from the control microparticle group. At the end of the study, we found that vaccination with adjuvanted survivin peptide microparticles resulted in statistically significant slower primary tumor growth rates in BALB/c mice challenged with 4T1 cells relative to the control peptideless vaccination group. These studies suggest that T cell immunotherapy specifically targeting survivin might be an applicable neoadjuvant immunotherapy therapy for triple negative breast cancer. More preclinical studies and clinical trials are needed to explore this concept further.

Abstract LBA030: DPX-SurMAGE, a novel dual-targeted immunotherapy for bladder cancer, induces target-specific T cells with a favorable safety profile in preclinical model

Abstract Thirty to forty percent of high-risk non-muscle invasive bladder cancer (NMIBC) fail standard of care, leaving radical cystectomy as the most recommended option for these patients. Therefore, new efficient and tolerable treatments are required to prevent or delay cystectomy. The DPX platform is a unique, water-free, lipid-based formulation that can deliver peptides, proteins, and small molecules specifically to antigen presenting cells (APCs), eliciting a targeted, robust, and sustained T cell-based immune response. Peptides that are packaged in DPX are specifically taken up by APCs. Maveropepimut-S (MVP-S, formerly known as DPX-Survivac) incorporates 5 HLA-restricted peptides derived from the anti-apoptotic protein survivin and is the first DPX-based immunotherapy. MVP-S demonstrated survivin-specific and sustained T cell response along with clinical activity and limited adverse events in patients with solid and hematologic tumors. Survivin and MAGE-A9 are well characterized tumor-associated antigens (TAAs) frequently overexpressed in bladder tumours. The DPX platform was leveraged to develop a new dual-targeted T cell activating immunotherapy, DPX-SurMAGE, incorporating HLA-A2 restricted peptides of both survivin and MAGE-A9. The feasibility of packaging peptides targeting two different TAAs into the DPX platform was assessed by performing comparative immunogenicity evaluation between 2 MVP-S peptides and DPX-SurMAGE in HLA-A2 transgenic mice. The magnitude of peptide-specific T cell responses against the shared HLA-A2 survivin peptide was similar in animals immunized with either DPX-SurMAGE or MVP-S indicating that the presence of MAGE-A9 peptides did not affect the immunogenicity of the MVP-S-based survivin peptide in the DPX-SurMAGE formulation. Immunogenicity and toxicity of DPX-SurMAGE with and without metronomic cyclophosphamide (mCPA) was further evaluated. IFN-γ ELISPOT assessment demonstrated robust induction of peptide-specific T cell responses to survivin and MAGE-A9 peptide pools. These strong responses were maintained at similar levels in the long-term chronic phase of the assessments both with and without mCPA. Preliminary safety observations including Detailed Clinical Examination (DCE), body weights and organ weights showed no sign of toxicity nor significant changes in mice treated with DPX-SurMAGE with or without mCPA. There were no significant differences in injection site reactions between DPX-SurMAGE groups (with and without mCPA). The local injection site reactions for DPX-SurMAGE groups were comparable to that of DPX-Empty control group. This study demonstrates the unique ability of the DPX delivery platform to deliver multiple antigenic TAA peptides without compromising the immunogenicity of each peptide. Furthermore, the DPX-SurMAGE treatment was well tolerated and was shown to induce robust and sustained target-specific T cell responses against both survivin and MAGE-A9 antigens, supporting the impending phase 1 clinical trial in high risk NMIBC patients. Citation Format: Valérie Picard, Valarmathy Kaliaperumal, Fanny Gaignier, Marjorie Besançon, Yogesh Bramhecha, Olga Hrytsenko, Alecia McKay, Stephan Fiset, Alain Bergeron, Yves Fradet. DPX-SurMAGE, a novel dual-targeted immunotherapy for bladder cancer, induces target-specific T cells with a favorable safety profile in preclinical model [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA030.

Abstract LBA026: Survivin peptides formulated in the DPX delivery platform rather than standard emulsions, elicit a robust, sustained T cell response to survivin in advanced and recurrent ovarian cancer patients

Abstract Despite improvements in peptide-based tumor antigen discovery, success in eliciting a clinically meaningful T cell response to these peptides has been limited. The choice of antigen delivery platform strongly impacts the quality, quantity, and durability of induced immune responses. DPX is a unique, water-free, lipid-based formulation that can deliver peptides, proteins, and small molecules specifically to antigen presenting cells (APCs), eliciting a targeted, robust, and sustained T cell-based immune response. DPX allows for antigenic peptides to remain at the site of injection without significant diffusion into surrounding tissues, in direct contrast to most emulsion-based delivery methods. Maveropepimut-S (MVP-S; formerly known as DPX-Survivac) is a DPX formulation that incorporates 5 HLA-restricted peptides derived from the anti-apoptotic protein survivin, which is commonly overexpressed in advanced cancers including ovarian cancer. Prior efforts with these same peptides emulsified in Montanide ISA 51 VG provided limited clinical benefit and no objective responses (Lennerz 2014). We now show in pre-clinical models that, when packaged in DPX, these peptides elicit higher avidity, more abundant and cytolytically-active survivin-specific T cells than standard emulsion-based formulations. Early clinical studies with MVP-S in advanced ovarian cancer patients have shown a persistent, survivin-specific T cell response, which in a subset of patients lasted more than 2 years. The recently completed phase 2 study of MVP-S and low-dose cyclophosphamide (CPA) in advanced and recurrent ovarian cancer subjects (DeCidE1), provided encouraging clinical benefit across multiple measures (ORR = 26% & DCR = 79% on target lesions, mOS = 19.9 months in evaluable patients). We now show that majority of patients in this study had survivin-specific T cells on treatment by in vitro tetramer staining (87%) and ex vivo ELISPOT analyses (56%). Importantly, 75% of patients deriving clinical benefit had active survivin-specific T cells by ex vivo ELISPOT analyses. Immunophenotyping of the longitudinally collected PBMCs showed evidence of sustained T cell proliferation by tetramer staining across time and did not show increased expression of immunosuppressive markers (e.g., PD-1, Tim3), suggesting that MVP-S induced T cells remain active over time. TCRβ analyses of tumor TCR repertoires further showed the ability of de novo elicited survivin-specific T cells to infiltrate on-treatment tumours. Collectively, these preclinical and clinical data show that MVP-S treatment effectively elicits a robust, persistent, survivin-specific T cell response. These data also provide compelling evidence that clinical benefit in DeCidE1 patients is most evident in those with survivin-specific T cells. Finally, these data further underscore the unique capacity of DPX technology to effectively elicit peptide-specific, T cell based immune responses when conventional formulations do not. Citation Format: Yogesh Bramhecha, Oliver Dorigo, Valarmathy Kaliaperumal, Heather Torrey, Walead Ebrahimizadeh, Kelcey Patterson, Brennan Dirk, Moamen Bydoun, Barry Kennedy, Aurelio Lobo, Genevieve Weir, Jeremy Graff, Stephan Fiset, Olga Hrytsenko. Survivin peptides formulated in the DPX delivery platform rather than standard emulsions, elicit a robust, sustained T cell response to survivin in advanced and recurrent ovarian cancer patients [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr LBA026.

The Presence of Survivin on B Cells from Myasthenia Gravis Patients and the Potential of an Antibody to a Modified Survivin Peptide to Alleviate Weakness in an Animal Model.

Myasthenia gravis (MG) is an autoimmune disease in which Abs target neuromuscular junction proteins, in particular the acetylcholine receptor. We previously identified the antiapoptotic protein survivin in the autoreactive B cells and plasma cells of MG patients. To further define the role of survivin in MG, we have assessed PBMCs from 29 patients with MG and 15 controls. We confirmed the increased expression of survivin in CD20+ lymphocytes from MG patients compared with controls. Furthermore, the CD20+ population of cells from MG patients contained a higher percentage of extracellular survivin compared with controls. The analysis of CD4+ cells showed an increased percentage of intracellular survivin in MG patients compared with controls, whereas the extracellular survivin CD4+ percentage was unaffected. In an experimental mouse model of MG, we assessed the therapeutic potential of an Ab raised to a modified survivin peptide but cross-reactive to survivin. Ab treatment reduced disease severity, lowered acetylcholine receptor-specific Abs, and decreased CD19+ survivin+ splenocytes. The ability to target survivin through Ab recognition of autoreactive cells offers the potential for a highly specific therapeutic agent for MG.

Novel Survivin Peptides Screened With Computer Algorithm Induce Cytotoxic T Lymphocytes With Higher Cytotoxic Efficiency to Cancer Cells.

The identification of novel biomarkers and therapeutic targets in advanced cancer is critical for improving cancer diagnosis and therapeutics. Survivin (SV) is highly expressed predominantly in most cancer cells and tissues but is absent or undetectable in terminally differentiated normal adult tissues. Therefore, it functions as an almost universal tumor antigen. Peptides are short chains of amino acids linked by peptide bonds. To obtain novel SV decamers that are able to induce SV-specific cytotoxic T lymphocytes (CTLs) with a higher cytotoxic efficiency against cancer cells, major histocompatibility complex (MHC) peptide binding algorithms were conducted to predict nine modified SV95 decamers (from SV95–2 to SV95–10) based on the natural SV95–104 peptide sequence of ELTLGEFLKL (here defined as SV95–1). The fluorescent density of each SV95 peptide was determined by a MHC stability assay, followed by the generation of SV95-specific CTLs with each SV95 peptide (from SV95–1 to SV95–10) and human dendritic cells (DCs) loaded with Poly(lactic-co-glycolic) acid (PLGA) nanoparticles encapsulated with SV95 peptide. Finally, IFN-γ ELISpot and CytoTox 96® Non-Radioactive Cytotoxicity Assays were employed to verify their cytotoxic efficiency of the SV95-specific CTLs generated with the corresponding artificial antigen presenting cells (aAPCs) containing SV95 (SV95–1 to SV95–10) peptide. Furthermore, the cytotoxicity of the SV95 specific CTLs generated with nine mutated SV95 peptides was compared to the one generated with natural SV95–1 peptide and TIL2080 cells. The results indicated that the HLA-A2-restricted mutated SV95 epitope decamers (SV95–6 and SV95–7) showed significant higher binding ability compared to natural peptide SV95–1 in MHC stability assay. More importantly, SV95–specific CTLs with higher cytotoxicity were successfully induced with both SV95–6 and SV95–7 peptides, which significantly eliminated target cells (not only SV95–1 peptide pulsed T2 cells, but also both HLA-A2 and SV positive cancer cells) when compared to those generated with natural SV95–1 peptide and TIL2080 cells. These findings suggest that the SV95–6 and SV95–7 peptides are two novel HLA-A2-restricted CTL epitopes and may be useful for the immunotherapy for patients with survivin expressing cancer.

Efficient induction of cytotoxic T lymphocytes in hepatocellular carcinoma using the HLA-A2-restricted survivin peptide in vitro

Survivin is a newly identified tumour-associated antigen and has been demonstrated to be an excellent target for immunotherapy in several cancers, but its role in hepatocellular carcinoma treatment is still unknown. In this study, survivin-derived peptide-specific cytotoxic T lymphocytes (CTLs) from peripheral blood mononuclear cells of healthy donors were induced by multiple stimulations with HLA-A2- restricted survivin peptide-pulsed T2 cells. The induced CTLs exhibited specific lysis of T2 cells pulsed with the peptide and HLA-A2+ hepatocellular carcinoma cells expressing survivin, while HLA-A2+ hepatocellular carcinoma cell lines that did not express survivin were not recognized by the CTLs. These results suggest that the survivin peptide epitope could be a potential target of specific immunotherapy for HLA-A2+ patients with hepatocellular carcinoma.

Optimization of the T2 HLA-A2 shift assay for testing of the biological activity of immunotherapies

Abstract T2 is a lymphoma-derived cell line that express low amounts of HLA-A2 on the cell surface due to TAP deficiency and can only present exogenous peptides. Binding of exogenous peptides to HLA-A2 stabilizes the HLA-A2- peptide complexes and can be detected using immunofluorescence staining. The T2 cell line is commonly used for identification and analysis of novel HLA-A2-restricted CTL epitopes in the assay known as T2 shift. In this study we evaluated parameters that may influence the T2 shift assay performance and considered new applications of this method for testing of the biological activity of peptide-based immunotherapies. Method optimization was performed using HLA-A2-restricted peptide SurA2.M alone and in the context of a peptide-based immunotherapy drug, DPX-Survivac. DPX-Survivac is a lipid nanoparticle-based formulation that contains five peptides aiming to elicit a CTL response against tumor cells presenting the survivin peptides on HLA class I molecules. Results indicated that performance of the T2 shift assay was highly sensitive to cell passaging intervals, pH variations, cell concentrations and β2-microglobulin concentrations. Discrimination of the T2 cells by either size or granularity did not affect the results for the T2 shift assay. We determined the linear response range for the SurA2.M peptide to be 30-110 μg/mL in the T2 shift assay. The T2 shift assay can detect SurA2.M within the DPX-Survivac matrix. In conclusion, we found that optimal culturing conditions of T2 cells are critical for the T2 shift assay reproducibility and linearity and should be carefully considered if the assay is to be used for quantitative or semi-quantitative evaluation of the peptide activity alone or as a part of an immunotherapeutic drug.

Dietary Protein Restriction Reprograms Tumor-Associated Macrophages and Enhances Immunotherapy.

Diet and healthy weight are established means of reducing cancer incidence and mortality. However, the impact of diet modifications on the tumor microenvironment and antitumor immunity is not well defined. Immunosuppressive tumor-associated macrophages (TAMs) are associated with poor clinical outcomes and are potentially modifiable through dietary interventions. We tested the hypothesis that dietary protein restriction modifies macrophage function toward antitumor phenotypes. Macrophage functional status under different tissue culture conditions and in vivo was assessed by Western blot, immunofluorescence, qRT-PCR, and cytokine array analyses. Tumor growth in the context of protein or amino acid (AA) restriction and immunotherapy, namely, a survivin peptide-based vaccine or a PD-1 inhibitor, was examined in animal models of prostate (RP-B6Myc) and renal (RENCA) cell carcinoma. All tests were two-sided. Protein or AA-restricted macrophages exhibited enhanced tumoricidal, proinflammatory phenotypes, and in two syngeneic tumor models, protein or AA-restricted diets elicited reduced TAM infiltration, tumor growth, and increased response to immunotherapies. Further, we identified a distinct molecular mechanism by which AA-restriction reprograms macrophage function via a ROS/mTOR-centric cascade. Dietary protein restriction alters TAM activity and enhances the tumoricidal capacity of this critical innate immune cell type, providing the rationale for clinical testing of this supportive tool in patients receiving cancer immunotherapies.

Effects of poly(I:C) and MF59 co-adjuvants on immunogenicity and efficacy of survivin polypeptide immunogen against melanoma.

Malignant tumors pose a public health problem that jeopardizes human life and quality of living. At present, tumor vaccines in clinical research typically are aimed at stimulating the cellular immune response, while more effective vaccines should take into account the synergy between broad spectrum antibodies and high levels of cellular immunity. In this study, epitope peptides (68-81, 95-104, 80-88) of the tumor antigen survivin were chosen as immunogens and supplemented with poly(I:C) and/or MF59 adjuvant to evaluate the immune effects and anti-melanoma activities. The results indicated that poly(I:C) and MF59 could assist the survivin epitope peptide immunogen to control the tumor size, quality, and volume in black melanoma mouse models. Analyses by antibody titering, antibody isotyping and ELISPOT suggested that the adjuvanted immunogen could induce humoral immunity in mice. Poly(I:C) and MF59 combined with survivin peptide 95-104 could effectively induce humoral immunity mediated by type 2 T helper (Th2) cells. This study provides a basis for candidate immunogen design based on survivin and provides support for tumor therapy that can induce a more balanced Th1/Th2 immune response.

Indoleamine 2,3-dioxygenase and survivin peptide vaccine combined with temozolomide in metastatic melanoma.

Indoleamine 2,3-dioxygenase (IDO) and survivin have been identified as potential targets for cancer vaccination. In this phase II study a vaccine using the peptides Sur1M2 and IDO5 was combined with the chemotherapy temozolomide (TMZ) for treatment of metastatic melanoma patients. The aim was to simultaneously target several immune inhibiting mechanisms and the highly malignant cells expressing survivin. HLA-A2 positive patients with advanced malignant melanoma were treated biweekly with 150 mg/m2 TMZ daily for 7 days followed by subcutaneous vaccination with 250 µg of each peptide in 500 µL Montanide solution at day 8. Granulocyte-macrophage colony-stimulating factor was used as an adjuvant and topical imiquimod was applied prior to vaccination. Treatment was continued until disease progression. Clinical response was evaluated by PET-CT and immunological outcome was assessed by ELISPOT and flow cytometry. In total, 17 patients were treated with a clinical benefit rate of 18% including one patient with partial tumor regression. Immune analyses revealed a vaccine specific response in 8 (67%) of 12 patients tested, a significant decrease in the frequency of CD4+ T-cells during treatment, a tendency towards decreasing frequencies of naïve CD4+ and CD8+ T-cells, and increasing frequencies of memory CD4+ and CD8+ T-cells. These results demonstrate that vaccine-induced immunity towards survivin and IDO-derived peptides can be achieved in combination with TMZ in patients mainly suffering from grade M1c melanoma including patients with brain metastases. A significant clinical activity could not be proven in this small study and a larger setup is needed to properly assess clinical efficacy.

Abstract 250: Methionine restriction increases macrophage tumoricidal activity and significantly inhibits prostate cancer growth

Abstract Background: Our previous work showed a significant reduction of tumor growth, macrophage infiltration, circulating IGF-1, and mTOR activation with low protein diet in a patient derived xenograft model of prostate cancer. The evolutionarily conserved, nutrient sensing, mTOR pathway plays a central role in both development of advanced stage prostate cancer and immune responsiveness. This study presents novel data on the impact of dietary protein modification on the function of the host immune system in response to prostate cancer and immunotherapy. Methods: Our In vitro studies utilized bone marrow or tumor derived (RP-B6 Myc) macrophages. In vivo studies utilized the recently characterized RP-B6 Myc model. Mice were fed ad libitum control or methionine restricted diets for four weeks prior to S.C. implantation with ~1mm2 tumor pieces. Treatment of survivin peptide vaccine (1mg/ml S.C. 1 X week) and anti-PD-1 (20mg/kg I.P. 2 X week) began at ~50mm2 tumor size. Tumor volumes were blindly recorded 2 X week. End point analyses include: tumor weight, flow cytometric analysis, proteomic profiler analyses, and microbiome analyses from each diet and treatment group. Results: We show here that while methionine restriction (MR) has little impact on our RP-B6 Myc prostate cancer cell line, it does yield a significant alteration in both the polarization and function of M1 and M2 macrophages. In the in vitro MR conditions, we observed significantly enhanced polarization of M1 macrophages and reduced polarization of M2 macrophages. Functional analysis revealed increased tumoricidal activity of both M1, ‘antitumor’, and M2, ‘pro-tumor,’ macrophages suggesting a flip in M2 function from tumor-promoting to tumoricidal. Further analysis of the released cytokines in MR media conditions yielded significant increase of antitumor cytokines & chemokines, such as IL-12, IL-27, CXCL9, CXCL10, CXCL11, CCL2, CCL4, and TNF-alpha, a double-edged sword which in our system correlates with decreased cancer cell viability upon co-culture with amino acid restricted M1 and M2 macrophages. Our preliminary results show dietary MR yielding a significant inhibition of prostate cancer growth in the RP-B6-Myc model and our ongoing study with survivin peptide vaccine and anti-PD-1 immunotherapies will be available to present in the conference. Conclusions: Our data suggest that restricting methionine is sufficient to alter both the polarization and tumoricidal function of macrophages. Our preliminarily results show that restricted dietary methionine is able to inhibit prostate cancer growth, modify the host immune response and better inhibit prostate cancer growth alone or in combination with immunotherapy. These results provide a strong basis to consider diet restriction as a means to limit cancer growth targeting tumor immune system and potentially to enhance cancer patient responses to immunotherapy. Citation Format: Ashley R. Orillion, Sreenivasulu Chintala, Remi Adelaiye-Ogala, Li Shen, Nur Damayanti, May Elbanna, Sreevani Arisa, Bennett Elzey, Chinghai Kao, Luigi Fontana, Roberto Pili. Methionine restriction increases macrophage tumoricidal activity and significantly inhibits prostate cancer growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 250. doi:10.1158/1538-7445.AM2017-250

The QuickSwitch Quant HLA-A*02:01 Tetramer Kit can be used for determining the biological activity of a cancer vaccine.

Abstract We have devised a fast and user-friendly assay (QuickSwitch™ Quant) that can both help determine binding of novel peptides to MHC class I molecules and generate new specificity MHC class I tetramers for peptide specific T cell detection. This study aimed to determine whether the QuickSwitch™ Quant HLA-A*02:01 Tetramer Kit can also be used for evaluating the biological activity of a vaccine. The tested vaccine was DPX-Survivac, an ovarian cancer vaccine candidate which consists of several survivin peptide antigens that are each restricted to a different human class I allele. We sought to evaluate the specificity and sensitivity of the QuickSwitch™ Quant HLA-A* 02:01 Tetramer Kit-PE for assessing the biological activity of SurA2.M, an HLA-A2-restricted peptide, in DPX-Survivac. The complete vaccine also contains non-HLA-A2 restricted peptides, lipids and a polynucleotide adjuvant. We tested the detection of the peptide prepared individually in a buffered solution or in the DPX-Survivac vaccine prepared in an aqueous formulation. Results indicate that peptide exchange rate of SurA2.M is similar whether it is dissolved individually in a buffered solution or mixed with other components of the vaccine. Results also may be dependent on the affinity of the peptide for HLA-A2. Thus, by optimizing a concentration curve using individual peptides, the QuickSwitch™ Quant HLA-A*02:01 Tetramer Kit can be used to quantify the concentration of HLA-A2 restricted peptides in simple solutions or more complex formulations.

Survivin Modulators: An Updated Patent Review (2011-2015).

Survivin is widely overexpressed in many forms of cancer and studies have related high survivin expression with poor survival rates. Although, there have been several attempts to target survivin, most therapeutics haven't shown substantial success in clinical trials therefore, authors wish to attract the focus towards many recent therapeutic innovations to target survivin. Survivin plays an essential role in the cell cycle progression, apoptosis, cell stress response, drug resistance and angiogenesis therefore the prognostic and targeting benefits of survivin have been underestimated. An update on the current and existing therapeutic strategies implemented to target survivin is provided. Therefore, the reader will gain an insight into the recent patents targeting survivin. The review has emphasised on patents for quantification of survivin, survivin peptides as immunotherapeutics, application of survivin promoters, RNA interference of survivin, small molecules inhibitors of survivin and nanoparticles targeting survivin. The review also encompasses the survivin targeted therapeutics being implemented at clinical stages which include survivin targeted immunotherapeutics, peptide-based vaccines, antisense oligonucleotides and chemical inhibitors. We reviewed recent patents based on preclinical anti-survivin therapies reported to date and it was concluded that gataparsen has been most widely used for anti-survivin therapy in clinical trials. It was also concluded that most therapeutic patents were focussed on development of natural anti-survivin therapeutics such as anti-survivin peptides or survivin anti-sense oligonucleotides in the recent years therefore, proving that natural proteins and nucleic acids has an upper hand over chemicals and synthetic drugs.

Abstract POSTER-THER-1415: Translational study of DPX-survivac peptide vaccine and metronomic cyclophosphamide using a novel HLA-A2/ survivin expressing ovarian tumor model to mimic phase I clinical data

Abstract Survivin, a member of the inhibitors of the apoptosis protein family, is involved in critical pathways of cancer cell growth and survival. Survivin overexpression is detected in 90% of epithelial ovarian cancers. DPX-Survivac is a peptide vaccine containing five survivin HLA class I peptides (A1, A2, A3, A24 and B7) and a universal HLA class II helper peptide derived from tetanus toxin (A16L) formulated in the novel adjuvanting vaccine platform DepoVaxTM. In a phase I clinical study DPX-Survivac was combined with a continuous (metronomic) low dose of cyclophosphamide (mCPA) to treat patients with advanced or recurrent ovarian cancer. In this study, we found mCPA significantly enhanced the immune responses induced by DPX-Survivac. In order to investigate this effect and to understand the mechanisms involved, we developed an ovarian tumor model in HLA-A2 transgenic mice. Vaccination of HLA-A2 transgenic mice generates an immune response towards the A2-restricted survivin peptide in DPX-Survivac. Mouse Ovarian Surface Epithelial (MOSE) cell lines are “natural” ovarian cancer models established by spontaneous in vitro transformation of primary ovarian surface epithelial cells. MOSE cell lines were confirmed to express HLA-A2 and overexpress survivin, and formed subcutaneous and intraperitoneal ovarian tumors when implanted into syngeneic recipients. HLA-A2 transgenic mice bearing MOSE tumors were treated with either DPX-Survivac, mCPA (administrated at 20 mg/kg/day in drinking water) or a combination of mCPA and DPX-Survivac. We found that combining DPX-Survivac with mCPA provided most effective control of tumor growth. Ex vivo IFN-γ ELISPOT revealed that mCPA increases immunogenicity of the DPX-Survivac in mice bearing MOSE tumors. Analysis of the blood and tumor microenvironment by RT-qPCR showed that mice treated with the combination therapy had an altered immune gene signature with increased cytotoxic T lymphocyte markers compared to mice treated with DPX-Survivac or metronomic cyclophosphamide alone. Our data indicates that the combination treatment enhances the infiltration of CD8+ T cells into tumors, enhancing tumor specific immune responses. In summary, we have established a new model of epithelial ovarian cancer in HLA-A2 transgenic mice. This model was used to investigate the immunogenicity and efficacy of DPX-Survivac, an HLA-restricted peptide vaccine with proven immunogenicity in human clinical trials, in combination with the immune modulator mCPA. This model can be used to explore mechanisms of establishment and progression of ovarian cancer as well as for evaluation of new treatment strategies including new immune modulator/ vaccine combinations. Citation Format: Olga Hrytsenko, Genevieve M. Weir, Mohan Karkada, Neil L. Berinstein, Marianne M. Stanford, Marc Mansour. Translational study of DPX-survivac peptide vaccine and metronomic cyclophosphamide using a novel HLA-A2/ survivin expressing ovarian tumor model to mimic phase I clinical data [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-THER-1415.

Survivin-specific CD4+ T cells are decreased in patients with survivin-positive myeloma.

BackgroundSurvivin is a small protein inhibitor of apoptosis and a tumor associated antigen. Survivin expression in multiple myeloma is associated with poor prognosis, disease progression, and drug resistance. The CD4+ response against survivin remains uncharacterized.MethodsIn order to better understand the anti-tumor immune response to survivin, and optimize vaccination strategies, we characterized the spontaneous CD4+CD25- T cell response against survivin in healthy donors and myeloma patients using survivin derived peptide pools.ResultsHealthy donors and myeloma patients’ CD4+CD25- T cells exhibited a proliferative and IFN-gamma response against survivin peptides loaded onto autologous dendritic cells. We employed limiting dilution analysis to quantify the precursor frequency of survivin reactive CD4+CD25- T cells. Multiple myeloma patients (range 0% to 2.2x10-3%, n=12) had fewer survivin reactive CD4+CD25- T cells than healthy blood donors (range 1.1x10-3 to 8.4x10-3%, n=10), p = 0.021. The survivin reactive CD4+CD25- T cell precursor frequency was inversely associated with tumor survivin mRNA expression (p = 0.0028, r = −1.0, n = 6), and survivin tumor protein expression by IHC (p = 0.0295, r = −0.67, n = 10). A full length mutant survivin protein-pulsed dendritic cell vaccine expanded survivin reactive CD4+CD25- T cells after 12 days of in vitro culture (range 0-540x,median = 42x), and expansion was achieved even in patients with low baseline survivin reactive CD4+ precursors.ConclusionsWe have, for the first time, quantified the circulating CD4+CD25- precursor frequency against survivin and demonstrated this is lower in myeloma patients than healthy donors. The number of survivin reactive CD4+CD25- T cells is inversely associated with tumor survivin expression suggesting suppression of survivin responsive CD4+CD25- T cells. Further exploration of a full length mutant survivin protein vaccine which expands survivin reactive CD4+ cells independent of the survivin reactive precursor frequency is warranted.Electronic supplementary materialThe online version of this article (doi:10.1186/s40425-015-0065-1) contains supplementary material, which is available to authorized users.

Thymic expression of a T-cell receptor targeting a tumor-associated antigen coexpressed in the thymus induces T-ALL

AbstractT-cell receptors (TCRs) and chimeric antigen receptors recognizing tumor-associated antigens (TAAs) can now be engineered to be expressed on a wide array of immune effectors. Engineered receptors targeting TAAs have most commonly been expressed on mature T cells, however, some have postulated that receptor expression on immune progenitors could yield T cells with enhanced potency. We generated mice (survivin-TCR-transgenic [Sur-TCR-Tg]) expressing a TCR recognizing the immunodominant epitope (Sur20-28) of murine survivin during early stages of thymopoiesis. Spontaneous T-cell acute lymphoblastic leukemia (T-ALL) occurred in 100% of Sur-TCR-Tg mice derived from 3 separate founders. The leukemias expressed the Sur-TCR and signaled in response to the Sur20-28 peptide. In preleukemic mice, we observed increased cycling of double-negative thymocytes expressing the Sur-TCR and increased nuclear translocation of nuclear factor of activated T cells, consistent with TCR signaling induced by survivin expression in the murine thymus. β2M−/− Sur-TCR-Tg mice, which cannot effectively present survivin peptides on class I major histocompatibility complex, had significantly diminished rates of leukemia. We conclude that TCR signaling during the early stages of thymopoiesis mediates an oncogenic signal, and therefore expression of signaling receptors on developing thymocytes with specificity for TAAs expressed in the thymus could pose a risk for neoplasia, independent of insertional mutagenesis.

Survivin and PSMA Loaded Dendritic Cell Vaccine for the Treatment of Prostate Cancer.

Dendritic cell (DC)-based vaccines are a promising therapeutic modality for cancer. Results from recent trials and approval of the first DC vaccine by the U.S. Food and Drugs Administration for prostate cancer have paved the way for DC-based vaccines. A total of 21 hormone refractory prostate cancer (HRPC) patients with a life expectancy >3 months were randomised into two groups. DC loaded with recombinant Prostate Specific Membrane Antigen (rPSMA) and recombinant Survivin (rSurvivin) peptides was administered as an subcutaneous (s.c.) injection (5×10(6) cells). Docetaxel (75 mg/m(2) intravenous (i.v.)) and prednisone (5 mg, bis in die (b.i.d.)) served as control. Clinical and immunological responses were evaluated. Primary endpoints were safety and feasibility; secondary endpoint was overall survival. Responses were evaluated on day 15, day 30, day 60, and day 90. DC vaccination was well tolerated with no signs of grade 2 toxicity. DC vaccination induced delayed-type hypersensitivity reactivity and an immune response in all patients. Objective Response Rate (ORR) by Response Evaluation Criteria in Solid Tumours (RECIST) was 72.7% (8/11) versus 45.4 (5/11) in the docetaxel arm and immune related response criteria (irRC) was 54.5% (6/11) compared with 27.2% (3/11) in the control arm. The DC arm showed stable disease (SD) in 6 patients, progressive disease (PD) in 3 patients, and partial remission (PR) in two patients compared to SD in 5 patients, PD in 6 patients, and PR in none in the docetaxel arm. There was a cellular response, disease stabilization, no adverse events, and partial remission with the rPSMA and rSurvivin primed DC vaccine.

Survivin-specific T cell receptor targets tumor but not T cells.

Survivin is a tumor-associated antigen (TAA) that inhibits apoptosis and is widely overexpressed in cancer cells; therefore, survivin has potential as a target for cancer immunotherapy. Application of HLA-A2-restricted survivin-specific T cell receptors (TCRs) isolated from allogeneic HLA-mismatched TCR repertoires has, however, been impeded by the inability of these TCRs to distinguish healthy cells expressing low levels of survivin from cancer cells with high survivin expression levels. Here, we identified an HLA-A2-restricted survivin-specific TCR isolated from autologous TCR repertoires that targets tumor cells in vitro and in vivo but does not cause fratricidal toxicity. Molecular modeling of the TCR-peptide-HLA ternary complexes and alanine scanning revealed that the autologously derived TCRs had tighter interactions with the survivin peptide than did fratricidal TCRs. Similar recognition patterns were observed among 7 additional TAA-specific TCRs isolated from allogeneic versus autologous repertoires. Together, the results from this study indicate that maximal peptide recognition is key for TCR selectivity and likely critical for reducing unwanted off-target toxicities. Moreover, isolating TCRs from autologous repertoires to maximize TCR selectivity has potential as a useful strategy to identify and select other shared tumor- and self-antigen-specific TCRs and ensure selective antitumor activity.