Biomimetic Glyconanoparticle Nanoghost Vaccine Based on Red Blood Cells.

Cancer antigens of choice include mutant DNA sequences encoding neo-antigens, selected cancer testis antigens, and differentiation antigens, in addition to viral antigens. Neo-antigens and viral antigens are the most attractive, because the T cell repertoire against these antigens has not been blunted by central thymic tolerance. Optimal vaccine platforms include DNA and RNA vaccines as well as synthetic long peptides and selected prime-boost protocols involving recombinant viruses encoding cancer antigens. The most effective cancer vaccines deliver concentrated antigen to both HLA class I and II molecules of DCs, promoting both CD4 and CD8 T cell responses. Suboptimal antigen selection, suboptimal vaccine design, and an immunosuppressive cancer microenvironment are the root causes of the lack of clinical efficacy of cancer vaccines in many clinical trials. Drugs or physical treatments can mitigate the immunosuppressive cancer microenvironment and include chemotherapeutics, radiation, inhibitors of T cell checkpoints, indoleamine 2,3-dioxygenase (IDO) inhibitors, agonists of selected TNF receptor family members, and inhibitors of undesirable cytokines. The specificity of therapeutic vaccination combined with such immunomodulation offers an attractive avenue for the development of future cancer therapies. Clinical benefit of certain therapeutic cancer vaccines has been established, usually by noting prolonged progression free or overall survival. Reviews of the properties and prospects of cancer vaccines have been listed below (1-3). The addition of one or more immunomodulation strategies may further enhance the potential of therapeutic cancer vaccines, including of those that have been only marginally active due to the immunosuppressive cancer microenvironment. We have established clinical benefit of a cancer vaccine as monotherapy in patients with premalignant disease induced by high risk human papilloma virus. Regression of lesions was associated with a better vaccine-induced immune response against the target antigens of the vaccine. However in patients with cervical cancer the vaccine monotherapy failed to install clinically effective immunity. Recently we showed in a pilot trial that vaccine-induced immunity could be markedly enhanced by combination with standard of care chemotherapy for late stage recurrent or metastatic cervical cancer. Increased levels of myeloid-derived suppressor cells were shown to be depleted by the carboplatin and paclitaxel chemotherapy to the low levels of healthy donors, while T cell numbers in PBMC remained intact. Timed vaccination with a single dose of vaccine at the MDSC nadir during chemotherapy led to a robust vaccine-induced T cell response (4). In a subsequent chemo-immunotherapy trial with three vaccine doses, spaced by three weeks, and in cohorts of patients at four different vaccine doses, the initiation and maintenance of robust tumor-specific T cell responses was confirmed and a broad dose response relationship of tumor-specific T cell responses was noted. Preliminary data on clinical outcomes relative to HPV-specific immune responses will be discussed. In summary, therapeutic benefit of cancer vaccines can be maximized in patients with established cancers by improving vaccine design and by using vaccines in combination with standard chemotherapies. In addition cancer vaccines can establish and/or maintain tumor-specific T cells in combination with checkpoint blockade or other immunomodulatory therapies. Finally, cancer vaccines can also help to sustain and expand adoptively transferred tumor-specific T cells.

Vaccines and immunotherapy have transformed the treatment modalities and prevention of several diseases including malignancy. Vaccines for infectious diseases have been in use for many decades, but very few cancer vaccines are approved for human use. These Cancer vaccines are either used prophylactically for preventing against infectious agents related to cancers or therapy for treating the existing malignancy. Therapeutic cancer vaccines undergo extensive preclinical and clinical trials in animals and human beings before its final administration. The clinical benefit of therapeutic cancer vaccines is to produce tumor regression, long-lasting antitumor memory, and prolonging the survival of individuals with lesser adverse incident. First-generation cancer vaccines were prepared from whole-cell (autologous or allogeneic) tumor lysates. The use of this cancer vaccine shows significant results in terms of survival and reduced recurrence rate of tumors. Second-generation cancer vaccines have specific tumor antigens (TA) for inducing humoral and cellular immune response without exhibiting signs of autoimmunity. Apart from whole cell, DNA, RNA, Protein, peptides can also contribute as the antigen part of a vaccine. Potent cancer vaccines deliver TAs to both MHC class I and II molecules of antigen-presenting cells which stimulate both CD4 and CD8 T-cell responses. Human papillomavirus and hepatitis B virus vaccines are the two prophylactic cancer vaccines recommended by the Food and Drug Administration for its use in cervical and hepatocellular cancers respectively. In therapeutic cancer vaccines, only three vaccines (sipuleucel-T cells, Bacillus Calmette–Guerin vaccine, and Talimogene laherparepvec) are approved for treatment of castration-resistant prostate cancer, bladder cancer, and inoperable melanoma, respectively. Cancer vaccines are now falling under the fourth modality of cancer treatment after chemotherapy, radiotherapy, and surgery. Therapeutic cancer vaccination has a promising path forward when it is combined with immunomodulation.

More than 85% of lung cancer cases are classified as non-small-cell lung cancer (NSCLC), with predicted 5-year survival of 16% (1). However, after many years of dismal prognosis we are now experiencing a revolution in lung cancer treatment. Apart from targeted therapies, the potential of immunotherapy has created great excitement in the oncology community and has ushered in a new era of optimism. Cancer immunotherapy encompasses different approaches designed either to boost or restore immune functions. Therapeutic cancer vaccines are designed to stimulate the immune system of a cancer patient to act against tumor antigens (2). Sipuleucel-T, a vaccine designed to stimulate an immune response to prostatic acid phosphatase (PAP), was the first cancer vaccine approved for treatment of metastatic prostate cancer (3). Talimogene laherparepvec (T-VEC) is the first oncolytic virus therapy approved for inoperable metastatic melanoma. Unfortunately, other therapeutic cancer vaccines such as MAGE-A3 or tecemotide have not proved successful in the treatment of NSCLC (4,5). Checkpoint blockade therapy releases the ’brakes’ of the immune system and enhances the anti-tumor T-cell response (6) and in 2015 two such therapies, nivolumab (7,8) and pembrolizumab (9) were approved for the treatment of NSCLC.

There are strong biologic and preclinical rationales for the development of therapeutic cancer vaccines; however, the clinical translation of this treatment strategy has been challenging. It is now understood that many previous clinical trials of cancer vaccines used target antigens or vaccine designs that inherently lacked sufficient immunogenicity to induce clinical responses. Despite the historical track record, breakthrough advances in cancer immunobiology and vaccine technologies have supported continued interest in therapeutic cancer vaccinations, with the hope that next-generation vaccine strategies will enable patients with cancer to develop long-lasting anti-tumor immunity. There has been substantial progress identifying antigens and vaccine vectors that lead to strong and broad T cell responses, tailoring vaccine designs to achieve optimal antigen presentation, and finding combination partners employing complementary mechanisms of action (e.g., checkpoint inhibitors) to overcome the diverse methods cancer cells use to evade and suppress the immune system. Results from randomized, phase 3 studies testing therapeutic cancer vaccines based on these advances are eagerly awaited. Here, we summarize the successes and failures in the clinical development of cancer vaccines, address how this historical experience and advances in science and technology have shaped efforts to improve vaccines, and offer a clinical perspective on the future role of vaccine therapies for cancer.

M. bovis strain Bacillus Calmette–Guérin (BCG) has been the only licensed live attenuated vaccine against tuberculosis (TB) for nearly one century and has also been approved as a therapeutic vaccine for bladder cancer treatment since 1990. During its long time usage, different adverse events (AEs) have been reported. However, the AEs associated with the BCG preventive TB vaccine and therapeutic cancer vaccine have not been systematically compared. In this study, we systematically collected various BCG AE data mined from the US VAERS database and PubMed literature reports, identified statistically significant BCG-associated AEs, and ontologically classified and compared these AEs related to these two types of BCG vaccine. From 397 VAERS BCG AE case reports, we identified 64 AEs statistically significantly associated with the BCG TB vaccine and 14 AEs with the BCG cancer vaccine. Our meta-analysis of 41 peer-reviewed journal reports identified 48 AEs associated with the BCG TB vaccine and 43 AEs associated with the BCG cancer vaccine. Among all identified AEs from VAERS and literature reports, 25 AEs belong to serious AEs. The Ontology of Adverse Events (OAE)-based ontological hierarchical analysis indicated that the AEs associated with the BCG TB vaccine were enriched in immune system (e.g., lymphadenopathy and lymphadenitis), skin (e.g., skin ulceration and cyanosis), and respiratory system (e.g., cough and pneumonia); in contrast, the AEs associated with the BCG cancer vaccine mainly occurred in the urinary system (e.g., dysuria, pollakiuria, and hematuria). With these distinct AE profiles detected, this study also discovered three AEs (i.e., chills, pneumonia, and C-reactive protein increased) shared by the BCG TB vaccine and bladder cancer vaccine. Furthermore, our deep investigation of 24 BCG-associated death cases from VAERS identified the important effects of age, vaccine co-administration, and immunosuppressive status on the final BCG-associated death outcome.

BackgroundWhen designing tumour vaccines, there are two primary types of antigens to consider: tumour-specific antigens (TSAs) and tumour-associated antigens (TAAs). TSAs, which derive from onco-viral antigens or gene mutation-driven neoantigens,...

Therapeutic cancer vaccines: From initial findings to prospects

Neoantigens in the immuno-oncology space.

In recent years, immunotherapy has emerged as a viable and attractive strategy for the treatment of prostate cancer. While there are multiple ways to target the immune system, therapeutic cancer vaccines and immune checkpoint inhibitors have been most successful in late-stage clinical trials. The landmark Food and Drug Administration approval of sipuleucel-T for asymptomatic or minimally symptomatic metastatic prostate cancer set the stage for ongoing phase III trials with the cancer vaccine PSA-TRICOM and the immune checkpoint inhibitor ipilimumab. A common feature of these immune-based therapies is the appearance of improved overall survival without short-term changes in disease progression. This class effect appears to be due to modulation of tumor growth rate kinetics, in which the activated immune system exerts constant immunologic pressure that slows net tumor growth. Emerging data suggest that the ideal population for clinical trials of cancer vaccines is patients with lower tumor volume and less aggressive disease. Combination strategies that combine immunotherapy with standard therapies have been shown to augment both immune response and clinical benefit.

Design of clinical trials for therapeutic cancer vaccines development

2588 Background: To increase the efficacy of peptide cancer vaccines, we developed a novel vaccine platform called DepoVax, an adjuvanted water-free depot formulation with the ability to generate enhanced immune responses. Naturally processed HLA-A2 restricted peptides that are selectively presented by breast, ovarian and prostate cancer cell lines, but not by normal HLA-A2+ cells, were used as antigens with a proprietary adjuvant and a T helper peptide epitope to create a therapeutic cancer vaccine, DPX-0907. Methods: A phase I clinical study was designed to examine the safety and immune activating potential of DPX-0907 in advanced stage breast, ovarian and prostate cancer patients. A total of 23 late stage cancer patients were recruited and were divided into two dose volume cohorts in a three immunization clinical protocol. Results: DPX-0907 proved to be safe with no serious adverse effects related to the vaccine reported. Of those evaluable for immunogenicity, all breast cancer patients (3/3), most of ovarian (5/6) and one third of prostate (3/9) cancer patients demonstrated immune response to one or more of seven antigenic peptides, resulting in a 61% response rate. Immune responses correlated with achievement of CR, PR or SD to last treatment. No difference in immune response rate or magnitude was seen between the two dose groups. DPX-0907 displayed strong immune induction potential, with 73% of immune responders showing responses with just one dose of vaccine. In 83% of responders, immune responses were detected at ≥2 time points post vaccination and 64% had a persistent immune response at one month post last vaccination. Immune monitoring showed peptide-specific CD8 T cells, and these T cells were able to secrete multiple Th1 cytokines indicating their multifunctionality, a feature attributable to cells that mediate protective responses. Conclusions: These data support the ability of DPX-0907 to elicit Th1 dominated, specific immunity and support the rationale for further testing in immunologically competent cancer patients. The novel DepoVax formulation may promote multifunctional memory responses with peptides from other tumor associated antigens.

N-glycolylneuraminic acid (NeuGc) epitopes, so called Hanganutziu-Deicher (HD) antigens, which are widely expressed on endothelial cells of all mammals except humans, are considered to be potential targets for natural and elicited anti-nonGalalpha1-3 Gal (Gal) antibodies in humans. We previously reported that anti-NeuGc antibodies were not detected in healthy humans by enzyme-linked immunosorbent assay (ELISA) using NeuGc-GM3-coated plates, and no antibody production was observed in patients with a history of exposure to pig cells. However, a recent paper has revealed that (i) anti-NeuGc antibodies to porcine red blood cells (PRBC) are detectable in most healthy humans, and (ii) the majority of anti-nonGal antibodies are specific for NeuGc epitopes. The purpose of this study was to reassess whether NeuGc is important as an immunogenic nonGal epitope. The binding of antibodies to PRBC and porcine aortic endothelial cells (PAEC) was compared. Cells were treated with (i) alpha-galactosidase, and then (ii) neuraminidase, which digests sialic acids, including NeuGc epitopes. Cells were incubated with human pooled sera, and applied to flow cytometric analysis. After enzyme digestion, almost complete reduction of Gal and NeuGc expression was confirmed by GS-IB4 and HU/Ch2-7 (a chicken monoclonal antibody against HD antigens), respectively. Trypsin, which removes membrane glycoproteins, and endoglycoceramidase which cleaves glycolipids, were used for differentiating between NeuGc-containing glycoproteins and glycolipids. Neuraminidase-treatment reduced the binding of immunoglobulin G (IgG) antibodies to PRBC; about half of the anti-nonGal IgG antibodies to PRBC were directed to NeuGc. In contrast, anti-nonGal antibodies to PAEC were not directed to NeuGc. Trypsin-treatment markedly reduced the expression of NeuGc only on PRBC. Endoglycoceramidase-treatment was followed by a greater reduction in NeuGc epitopes on PAEC than on PRBC. Most NeuGc on PRBC appeared to be linked to proteins, but most NeuGc on PAEC was expressed on glycolipids. Carbohydrate structures on PRBC are different from those on PAEC. Healthy human sera contain anti-nonGal IgG antibodies to NeuGc expressed on PRBC, but not on PAEC. We speculate that anti-nonGal IgG antibodies to PRBC can recognize both NeuGc and protein, and this may be the reason why such antibodies have not been detected by ELISA. A definite conclusion about the immunogenicity of NeuGc has not been obtained. More sera from patients (not from non-human primates) sensitized with porcine cells or organs need to be studied.

Radiation has long been the standard of care for many types of cancer. It is employed to locally eradicate tumor cells as well as alter tumor stroma with either curative or palliative intent. Radiation-induced cell damage is an immunologically active process in which danger signals are released that stimulate immune cells to phagocytose and present locally released tumor-associated antigens (TAAs). Recent studies have indicated that radiotherapy can also alter the phenotype of cancer cells that remain after treatment. These cells upregulate TAAs as well as markers, including major histocompatibility complex and costimulatory molecules, that make them much more immunostimulatory. As our understanding of the immunomodulatory effects of radiation has improved, interest in combining this type of therapy with immune-based therapies for the treatment of cancer has grown. Therapeutic cancer vaccines have been shown to initiate the dynamic process of host immune system activation, culminating in the recognition of host cancer cells as foreign. The environment created after radiotherapy can be exploited by active therapeutic cancer vaccines in order to achieve further, more robust immune system activation. This review highlights preclinical studies that have examined the alteration of the tumor microenvironment with regard to immunostimulatory molecules following different types of radiotherapy, including external beam radiation, radiolabeled monoclonal antibodies, bone-seeking radionuclides, and brachytherapy. We also emphasize how combination therapy with a cancer vaccine can exploit these changes to achieve improved therapeutic benefit. Lastly, we describe how these laboratory findings are translating into clinical benefit for patients undergoing combined radiotherapy and cancer vaccination.

BackgroundTh-Vac® discovery platform, consists of module 1 (Immunoinformatics-based in-silico) and module 2 (in-vitro and vaccine efficacy evaluation) under the comprehensive immunologic algorithms, is aimed to identify antigen-specific MHC class II...

Water-in-oil emulsion incomplete Freund’s adjuvant (IFA) has been used as an adjuvant in preventive and therapeutic vaccines since its development. New generation, highly purified modulations of the adjuvant, Montanide incomplete...