Peptide vaccination of patients with metastatic melanoma: improved clinical outcome in patients demonstrating effective immunization

Potential role of immunotherapy and targeted therapy in the treatment of cancer: A contemporary nursing practice

Immunotherapy and targeted therapy have emerged as promising therapeutic options for cancer patients. Immunotherapies induce a host immune response that mediates long-lived tumor destruction, while targeted therapies suppress molecular mechanisms that are important for tumor maintenance and growth. In addition, cytotoxic agents and targeted therapies regulate immune responses, which increases the chances that these therapeutic approaches may be efficiently combined with immunotherapy to ameliorate clinical outcomes. Various studies have suggested that combinations of therapies that target different stages of anti-tumor immunity may be synergistic, which can lead to potent and more prolonged responses that can achieve long-lasting tumor destruction. Nurses associated with cancer patients should have a better understanding of the immunotherapies and targeted therapies, such as their efficacy profiles, mechanisms of action, as well as management and prophylaxis of adverse events. Indeed, this knowledge will be important in establishing care for cancer patients receiving immunotherapies and targeted therapies for cancer treatment. Moreover, nurses need a better understanding regarding targeted therapies and immunotherapies to ameliorate outcomes in patients receiving these therapies, as well as management and early detection of possible adverse effects, especially adverse events associated with checkpoint inhibitors and various other therapies that control T-cell activation causing autoimmune toxicity. Nurses practice in numerous settings, such as hospitals, home healthcare agencies, radiation therapy facilities, ambulatory care clinics, and community agencies. Therefore, as compared to other members of the healthcare team, nurses often have better opportunities to develop the essential rapport in providing effective nurse-led patient education, which is important for effective therapeutic outcomes and continuance of therapy. In this article, we have particularly focused on providing a detailed overview on targeted therapies and immunotherapies used in cancer treatment, management of their associated adverse events, and the impact as well as strategies of nurse-led patient education.

Potential association factors for developing effective peptide-based cancer vaccines

Peptide-based cancer vaccines have been shown to boost immune systems to kill tumor cells in cancer patients. However, designing an effective T cell epitope peptide-based cancer vaccine still remains a challenge and is a major hurdle for the application of cancer vaccines. In this study, we constructed for the first time a library of peptide-based cancer vaccines and their clinical attributes, named CancerVaccine (https://peptidecancervaccine.weebly.com/). To investigate the association factors that influence the effectiveness of cancer vaccines, these peptide-based cancer vaccines were classified into high (HCR) and low (LCR) clinical responses based on their clinical efficacy. Our study highlights that modified peptides derived from artificially modified proteins are suitable as cancer vaccines, especially for melanoma. It may be possible to advance cancer vaccines by screening for HLA class II affinity peptides may be an effective therapeutic strategy. In addition, the treatment regimen has the potential to influence the clinical response of a cancer vaccine, and Montanide ISA-51 might be an effective adjuvant. Finally, we constructed a high sensitivity and specificity machine learning model to assist in designing peptide-based cancer vaccines capable of providing high clinical responses. Together, our findings illustrate that a high clinical response following peptide-based cancer vaccination is correlated with the right type of peptide, the appropriate adjuvant, and a matched HLA allele, as well as an appropriate treatment regimen. This study would allow for enhanced development of cancer vaccines.

A Bayesian network meta-analysis of comparison of cancer therapeutic vaccines for melanoma

Several approaches to active immunotherapy for melanoma, including peptide-based vaccines (PVs), autologous tumour cell vaccines (TCVs), allogeneic TCVs and autologous dendritic cell vaccines (DCVs), have been investigated in clinical trials. However, comprehensive evidence comparing these interventions remains unavailable. The objective of this study was to expand previous work to compare and rank the immunotherapeutic strategies for melanoma in terms of overall survival and toxic effects with a Bayesian network meta-analysis. Methodologically, we performed a network meta-analysis of head-to-head randomized controlled trials comparing and ranking cancer vaccine approaches for patients with melanoma. PubMed, MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, the WHO International Clinical Trials Registry Platform and ClinicalTrials.gov were searched up to 31 July 2020. We estimated summary hazard ratios for death and risk ratios for toxicity. The effects of the underlying prognostic variable on survival benefits were examined by meta-regression. We performed subgroup analysis for the outcomes based on metastatic categories. Overall, we identified 4776 citations, of which 15 head-to-head randomized controlled trials (3162 participants) were included in the analysis. In terms of efficacy, allogeneic tumour cell vaccines plus immunotherapy adjuvants, peptide-based vaccines plus immunotherapy adjuvants and standard therapy were more effective than peptide vaccines. The proportion of women was inversely associated with mortality risk. For safety, all treatments were inferior to allogeneic tumour cell vaccines except for allogeneic tumour cell vaccines plus chemotherapy. Peptide vaccines plus immunotherapy adjuvants led to an increased risk of adverse events compared to allogeneic tumour cell vaccines plus immunotherapy adjuvants. These results suggest that allogeneic TCV and autologous DCV are better than standard therapy. PV plus immune modulators are the most effective strategy among all comparable strategies but is associated with increased toxicity. Any combination regimens for cancer therapeutic vaccines need to be balanced between risk and benefit profiles.

Trial watch: Peptide vaccines in cancer therapy

Prophylactic vaccination constitutes one of the most prominent medical achievements of history. This concept was first demonstrated by the pioneer work of Edward Jenner, dating back to the late 1790s, after which an array of preparations that confer life-long protective immunity against several infectious agents has been developed. The ensuing implementation of nation-wide vaccination programs has de facto abated the incidence of dreadful diseases including rabies, typhoid, cholera and many others. Among all, the most impressive result of vaccination campaigns is surely represented by the eradication of natural smallpox infection, which was definitively certified by the WHO in 1980. The idea of employing vaccines as anticancer interventions was first theorized in the 1890s by Paul Ehrlich and William Coley. However, it soon became clear that while vaccination could be efficiently employed as a preventive measure against infectious agents, anticancer vaccines would have to (1) operate as therapeutic, rather than preventive, interventions (at least in the vast majority of settings), and (2) circumvent the fact that tumor cells often fail to elicit immune responses. During the past 30 y, along with the recognition that the immune system is not irresponsive to tumors (as it was initially thought) and that malignant cells express tumor-associated antigens whereby they can be discriminated from normal cells, considerable efforts have been dedicated to the development of anticancer vaccines. Some of these approaches, encompassing cell-based, DNA-based and purified component-based preparations, have already been shown to exert conspicuous anticancer effects in cohorts of patients affected by both hematological and solid malignancies. In this Trial Watch, we will summarize the results of recent clinical trials that have evaluated/are evaluating purified peptides or full-length proteins as therapeutic interventions against cancer.

A pilot clinical trial testing topical resiquimod and a xenopeptide as immune adjuvants for a melanoma vaccine targeting MART-1

A vaccine that could expand melanoma-specific T cells might reduce the risk of recurrence of resected melanoma and could provide an alternative or adjunct to standard immunotherapy options. We tested the safety and immunogenicity of a vaccine coupling a melanoma-associated peptide with a xenogenic peptide (to promote epitope spreading) and/or resiquimod (to activate antigen-presenting cells). HLA-A2-positive patients with resected stage II, III, and IV melanoma were assigned to treatment on one of three schedules. All patients received three subcutaneous doses of the peptide MART-1a mixed with Montanide. In addition, patients on schedule 1 received the xenoantigen peptide Gag267-274, patients on schedule 2 received topical resiquimod, and patients on schedule 3 received both Gag267-274 and resiquimod. Blood samples were tested for the frequency of antigen-specific T cells by tetramer assay, as well as immune cell subtypes and plasma cytokine levels. Patients enrolled from October 2012 to December 2014, with 10 patients enrolling to each schedule. The most common adverse events were injection site reaction (26 patients) and fatigue (15 patients). Tetramer analysis revealed antigen-specific responses (defined as doubling of MART-1a-specific T cells from pretreatment to post-treatment) in 20, 60, and 40% of patients treated on schedules 1, 2, and 3, respectively. Vaccine treatment consisting of MART-1a peptide, Gag267-274, Montanide, and topical resiquimod was well-tolerated. The addition of the Gag267-274 xenoantigen was not associated with an increase in the response to MART-1a, whereas use of topical resiquimod was associated with a higher frequency of MART-1a-specific T-cell responses that did not meet statistical significance.

The Future of Immunotherapy in the Treatment of Cancer

OBJECTIVES

To discuss future direction and present an overview of the evolution of immunotherapy long-term toxicity issues, financial toxicity, and new emerging survivorship considerations.

DATA SOURCES

Peer-reviewed manuscripts, Web sites.

CONCLUSION

Cancer treatments involving immunotherapy have had a major impact on long-term survival, toxicity, and survivorship issues.

IMPLICATIONS FOR NURSING PRACTICE

Nurses play a pivotal role in the care of the cancer patient across the continuum. With the unique toxicities associated with immunotherapy, it is essential that nurses be keenly aware of all aspects of management, from physical to financial care.

Checkpoints and beyond - Immunotherapy in colorectal cancer

Immunotherapy is the latest revolution in cancer therapy. It continues to show impressive results in malignancies like melanoma and others. At least so far, effects are modest in colorectal cancer (CRC) and only a subset of patients benefits from already approved checkpoint inhibitors. In this review, we discuss major hurdles of immunotherapy like the immunosuppressive niche and low immunogenicity of CRC next to current achievements of checkpoint inhibitors, interleukin treatment and adoptive cell transfer (dendritic cells/cytokine induced killer cells, tumor infiltrating lymphocytes, chimeric antigen receptor cells, T cell receptor transfer) in pre-clinical models and clinical trials. We intensively examine approaches to overcome low immunogenicity by combination of different therapies and address future strategies of therapy as well as the need of predictive factors in this emerging field of precision medicine.

Cancer immunotherapy: moving forward with peptide T cell vaccines

Recent advances in cancer immunology, such as the discovery of immune checkpoint inhibitors, have validated immune cells as potential key players for effective cancer treatment. The efficacy of these therapies seems to be codependent on a tumor-reactive T lymphocyte response. For many years, numerous attempts and strategies in developing vaccines to generate tumor-reactive T cells have yielded poor results in the clinic due to suboptimal immunogenicity and the inability to overcome an immunosuppressive tumor microenvironment. In this review, we summarize past and current advances in T cell vaccines and describe our experience in developing optimized methods for antigen/adjuvant selection and vaccine administration in order to induce powerful anti-tumor responses.

Single vs. combination immunotherapeutic strategies for glioma

INTRODUCTION

Malignant gliomas are highly invasive tumors, associated with a dismal survival rate despite standard of care, which includes surgical resection, radiotherapy and chemotherapy with temozolomide (TMZ). Precision immunotherapies or combinations of immunotherapies that target unique tumor-specific features may substantially improve upon existing treatments. Areas covered: Clinical trials of single immunotherapies have shown therapeutic potential in high-grade glioma patients, and emerging preclinical studies indicate that combinations of immunotherapies may be more effective than monotherapies. In this review, the authors discuss emerging combinations of immunotherapies and compare efficacy of single vs. combined therapies tested in preclinical brain tumor models. Expert opinion: Malignant gliomas are characterized by a number of factors which may limit the success of single immunotherapies including inter-tumor and intra-tumor heterogeneity, intrinsic resistance to traditional therapies, immunosuppression, and immune selection for tumor cells with low antigenicity. Combination of therapies which target multiple aspects of tumor physiology are likely to be more effective than single therapies. While a limited number of combination immunotherapies are described which are currently being tested in preclinical and clinical studies, the field is expanding at an astounding rate, and endless combinations remain open for exploration.

Systematic review of the use of granulocyte-macrophage colony-stimulating factor in patients with advanced melanoma

Several immunomodulatory checkpoint inhibitors have been approved for the treatment of patients with advanced melanoma, including ipilimumab, nivolumab and pembrolizumab. Talimogene laherparepvec is the first oncolytic virus to gain regulatory approval in the USA; it is also approved in Europe. Talimogene laherparepvec expresses granulocyte–macrophage colony-stimulating factor (GM-CSF), and with other GM-CSF-expressing oncolytic viruses in development, understanding the clinical relevance of this cytokine in treating advanced melanoma is important. Results of trials of GM-CSF in melanoma have been mixed, and while GM-CSF has the potential to promote anti-tumor responses, some preclinical data suggest that GM-CSF may sometimes promote tumor growth. GM-CSF has not been approved as a melanoma treatment. We undertook a systematic literature review of studies of GM-CSF in patients with advanced melanoma (stage IIIB–IV). Of the 503 articles identified, 26 studies met the eligibility criteria. Most studies investigated the use of GM-CSF in combination with another treatment, such as peptide vaccines or chemotherapy, or as an adjuvant to surgery. Some clinical benefit was reported in patients who received GM-CSF as an adjuvant to surgery, or in combination with other treatments. In general, outcomes for patients receiving peptide vaccines were not improved with the addition of GM-CSF. GM-CSF may be a valuable therapeutic adjuvant; however, further studies are needed, particularly head-to-head comparisons, to confirm the optimal dosing regimen and clinical effectiveness in patients with advanced melanoma.

Designing therapeutic cancer vaccines by mimicking viral infections

The design of efficacious and cost-effective therapeutic vaccines against cancer remains both a research priority and a challenge. For more than a decade, our laboratory has been involved in the development of synthetic peptide-based anti-cancer therapeutic vaccines. We first dedicated our efforts in the identification and validation of peptide epitopes for both CD8 and CD4 T cells from tumor-associated antigens (TAAs). Because of suboptimal immune responses and lack of therapeutic benefit of peptide vaccines containing these epitopes, we have focused our recent efforts in optimizing peptide vaccinations in mouse tumor models using numerous TAA epitopes. In this focused research review, we describe how after taking lessons from the immune system's way of dealing with acute viral infections, we have designed peptide vaccination strategies capable of generating very high numbers of therapeutically effective CD8 T cells. We also discuss some of the remaining challenges to translate these findings into the clinical setting.

Effective immuno-targeting of the IDH1 mutation R132H in a murine model of intracranial glioma

The R132H mutation of cytosolic isocitrate dehydrogenase (IDH1) is present in the majority of low grade gliomas.Immunotherapy in these tumors has an interesting, still unexploited, therapeutic potential, as they are less immunosuppressive than glioblastomas. Using site-directed mutagenesis we introduced the R132H mutation into the murine glioma cell line GL261,creating mIDH1-GL261. Presence of the mutation was confirmed by immunoblotting and production of the oncometabolite 2-hydroxyglutarate (2HG), demonstrated by mass spectrometry (LC-MS/MS) performed on cell supernatant. In vitro mIDH1-GL261 had different morphology but similar growth rate than parental GL261 (p-GL261). After intracranial injection, MRI suggested that the initial growth rate was slower in mIDH1-GL261 than p-GL261 gliomas but overall survival was similar. mIDH1-GL261 gliomas showed evidence of R132H expression and of intratumoral 2HG production (evaluated by MRS and LC-MS/MS). Immunizations were performed nine days after intracranial implantation of mIDH1- or p-GL261 cells by three subcutaneous injections of five different peptides encompassing the IDH1 mutation site, all emulsified with Montanide ISA-51, in association with GM-CSF. Control mice were injected with four ovalbumin peptides or vehicle. Mice with mIDH1-GL261 but not p-GL261 gliomas treated with mIDH1 peptides survived longer than controls; 25% of them were cured. Immunized mice showed higher amounts of peripheral CD8+ T cells, higher production of IFN-γ, and evidence of anti-mIDH1 antibodies.Immunizations led to intratumoral up-regulation of IFN-γ, granzyme-b and perforin-1 and down-regulation of TGF-β2 and IL-10. These results support the translational potential of immunotherapeutic targeting of gliomas carrying IDH1 mutations.

Vaccine Potentiation by Combination Adjuvants

Adjuvants are crucial components of vaccines. They significantly improve vaccine efficacy by modulating, enhancing, or extending the immune response and at the same time reducing the amount of antigen needed. In contrast to previously licensed adjuvants, current successful adjuvant formulations often consist of several molecules, that when combined, act synergistically by activating a variety of immune mechanisms. These "combination adjuvants" are already registered with several vaccines, both in humans and animals, and novel combination adjuvants are in the pipeline. With improved knowledge of the type of immune responses needed to successfully induce disease protection by vaccination, combination adjuvants are particularly suited to not only enhance, but also direct the immune responses desired to be either Th1-, Th2- or Th17-biased. Indeed, in view of the variety of disease and population targets for vaccine development, a panel of adjuvants will be needed to address different disease targets and populations. Here, we will review well-known and new combination adjuvants already licensed or currently in development-including ISCOMs, liposomes, Adjuvant Systems Montanides, and triple adjuvant combinations-and summarize their performance in preclinical and clinical trials. Several of these combination adjuvants are promising having promoted improved and balanced immune responses.

Towards tailored vaccine delivery: needs, challenges and perspectives

The ideal vaccine is a simple and stable formulation which can be conveniently administered and provides life-long immunity against a given pathogen. The development of such a vaccine, which should trigger broad and strong B-cell and T-cell responses against antigens of the pathogen in question, is highly dependent on tailored vaccine delivery approaches. This review addresses vaccine delivery in its broadest scope. We discuss the needs and challenges in the area of vaccine delivery, including restrictions posed by specific target populations, potentials of dedicated stable formulations and devices, and the use of adjuvants. Moreover, we address the current status and perspectives of vaccine delivery via several routes of administration, including non- or minimally invasive routes. Finally we suggest possible directions for future vaccine delivery research and development.

The Akt signaling pathway: an emerging therapeutic target in malignant melanoma

Studies using cultured melanoma cells and patient tumor biopsies have demonstrated deregulated PI3 kinase-Akt3 pathway activity in ~70% of melanomas. Furthermore, targeting Akt3 and downstream PRAS40 has been shown to inhibit melanoma tumor development in mice. Although these preclinical studies and several other reports using small interfering RNAs and pharmacological agents targeting key members of this pathway have been shown to retard melanoma development, analysis of early Phase I and Phase II clinical trials using pharmacological agents to target this pathway demonstrate the need for (1) selection of patients whose tumors have PI3 kinase-Akt pathway deregulation, (2) further optimization of therapeutic agents for increased potency and reduced toxicity, (3) the identification of additional targets in the same pathway or in other signaling cascades that synergistically inhibit the growth and progression of melanoma, and (4) better methods for targeted delivery of pharmaceutical agents inhibiting this pathway. In this review we discuss key potential targets in PI3K-Akt3 signaling, the status of pharmacological agents targeting these proteins, drugs under clinical development, and strategies to improve the efficacy of therapeutic agents targeting this pathway.

Vaccination of patients with cutaneous melanoma with telomerase-specific peptides

PURPOSE

A phase I study was conducted to investigate the safety, tolerability, and immunological responses to vaccination with a combination of telomerase-derived peptides GV1001 (hTERT: 611-626) and p540 (hTERT: 540-548) using granulocyte-macrophage colony-stimulating factor (GM-CSF) or tuberculin as adjuvant in patients with cutaneous melanoma.

EXPERIMENTAL DESIGN

Ten patients with melanoma stages UICC IIb-IV were vaccinated 8 times intradermally with either 60 or 300 nmole of GV1001 and p540 peptide using GM-CSF as adjuvant. A second group of patients received only 300 nmole GV1001 in combination with tuberculin PPD23 injections. HLA typing was not used as an inclusion criterion. Peptide-specific immune responses were measured by delayed-type hypersensitivity (DTH) reactions, in vitro T cell proliferation assays, and cytotoxicity (51-Chromium release) assays for a selected number of clones subsequently generated.

RESULTS

Vaccination was well tolerated in all patients. Peptide-specific immune response measured by DTH reactions and in vitro response could be induced in a dose-dependent fashion in 7 of 10 patients. Cloned T cells from the vaccinated patients showed proliferative responses against both vaccine peptides GV1001 and p540. Furthermore, T cell clones were able to specifically lyse p540-pulsed T2 target cells and various pulsed and unpulsed tumor cell lines.

CONCLUSION

These results demonstrate that immunity to hTERT can be generated safely and effectively in patients with advanced melanoma and therefore encourage further trials.

A gynecologic oncology group phase II trial of two p53 peptide vaccine approaches: subcutaneous injection and intravenous pulsed dendritic cells in high recurrence risk ovarian cancer patients

PURPOSE

Peptide antigens have been administered by different approaches as cancer vaccine therapy, including direct injection or pulsed onto dendritic cells; however, the optimal delivery method is still debatable. In this study, we describe the immune response elicited by two vaccine approaches using the wild-type (wt) p53 vaccine.

EXPERIMENTAL DESIGN

Twenty-one HLA-A2.1 patients with stage III, IV, or recurrent ovarian cancer overexpressing the p53 protein with no evidence of disease were treated in two cohorts. Arm A received SC wt p53:264-272 peptide admixed with Montanide and GM-CSF. Arm B received wt p53:264-272 peptide-pulsed dendritic cells IV. Interleukin-2 (IL-2) was administered to both cohorts in alternative cycles.

RESULTS

Nine of 13 patients (69%) in arm A and 5 of 6 patients (83%) in arm B developed an immunologic response as determined by ELISPOT and tetramer assays. The vaccine caused no serious systemic side effects. IL-2 administration resulted in grade 3 and 4 toxicities in both arms and directly induced the expansion of T regulatory cells. The median overall survival was 40.8 and 29.6 months for arm A and B, respectively; the median progression-free survival was 4.2 and. 8.7 months, respectively.

CONCLUSION

We found that using either vaccination approach generates comparable specific immune responses against the p53 peptide with minimal toxicity. Accordingly, our findings suggest that the use of less demanding SC approach may be as effective. Furthermore, the use of low-dose SC IL-2 as an adjuvant might have interfered with the immune response. Therefore, it may not be needed in future trials.

Cancer immunotherapy

Cancer immunotherapy consists of approaches that modify the host immune system, and/or the utilization of components of the immune system, as cancer treatment. During the past 25 years, 17 immunologic products have received regulatory approval based on anticancer activity as single agents and/or in combination with chemotherapy. These include the nonspecific immune stimulants BCG and levamisole; the cytokines interferon-α and interleukin-2; the monoclonal antibodies rituximab, ofatumumab, alemtuzumab, trastuzumab, bevacizumab, cetuximab, and panitumumab; the radiolabeled antibodies Y-90 ibritumomab tiuxetan and I-131 tositumomab; the immunotoxins denileukin diftitox and gemtuzumab ozogamicin; nonmyeloablative allogeneic transplants with donor lymphocyte infusions; and the anti-prostate cancer cell-based therapy sipuleucel-T. All but two of these products are still regularly used to treat various B- and T-cell malignancies, and numerous solid tumors, including breast, lung, colorectal, prostate, melanoma, kidney, glioblastoma, bladder, and head and neck. Positive randomized trials have recently been reported for idiotype vaccines in lymphoma and a peptide vaccine in melanoma. The anti-CTLA-4 monoclonal antibody ipilumumab, which blocks regulatory T-cells, is expected to receive regulatory approval in the near future, based on a randomized trial in melanoma. As the fourth modality of cancer treatment, biotherapy/immunotherapy is an increasingly important component of the anticancer armamentarium.

Differential response of human and mouse dendritic cells to VEGF determines interspecies discrepancies in tumor-mediated TH1/TH2 polarity shift

PURPOSE

Metastatic cancer patients exhibit systemic dysregulation of immune polarity and are biased toward Th-2 immune responses. This is due, at least in part, to effects of VEGF on antigen presenting cell (APC) function. We therefore compared immune polarity changes in mouse models of cancer with those seen in human patients.

EXPERIMENTAL DESIGN

We measured plasma levels of vascular growth factors and multiple cytokines via ELISA and multiplex analysis in mice with transplantable and spontaneous tumors. We compared immune cell subsets in naive and vaccinated mice with and without tumors. We assessed cytokine immune responses by multiplex analysis. Finally, we assessed gene expression and receptor surface expression in response to VEGF in mouse and human APCs.

RESULTS

Although human patients have elevated plasma cytokines and altered immune polarity in response to antigen, mice have minimal immune abnormalities. Mouse VEGF does not mediate immune repolarization in vitro. Human but not mouse APCs upregulate VEGFR2 and downregulate interleukin (IL)-12β in response to VEGF.

CONCLUSIONS

Whereas humans with metastatic cancer demonstrate dysregulated immune polarity in response to excess plasma VEGF, tumor mice do not. This appears to be due to differences in APC responses to VEGF stimulation. Differential immune effects of VEGF may represent a key species difference in the context of translation of preclinical cancer immunotherapeutics into early clinical testing.

Transcutaneous immunization with hydrophilic recombinant gp100 protein induces antigen-specific cellular immune response

The objective of this study was to evaluate the potential of transcutaneous immunization with tumor antigen to induce cell-mediated immunity. For this purpose, hydrophilic recombinant gp100 protein (HR-gp100) was topically applied on human intact skin in vitro, and used as a vaccine in a mouse model. We demonstrate that HR-gp100 permeates into human skin, and is processed and presented by human dendritic cells. In a mouse model, an HR-gp100-based vaccine triggered antigen-specific T cell responses, as shown by proliferation assays, ELISA and intracellular staining for IFN-γ. Transcutaneous antigen delivery may provide a safe, simple and effective method to elicit cell-mediated immunity.

Immunogenicity and antitumor effects of vaccination with peptide vaccine+/-granulocyte-monocyte colony-stimulating factor and/or IFN-alpha2b in advanced metastatic melanoma: Eastern Cooperative Oncology Group Phase II Trial E1696

PURPOSE

No therapy has ever shown prolongation of survival in stage IV metastatic melanoma. The association of cytokine-induced autoimmunity with improved prognosis led us to investigate the effect of multi-epitope melanoma vaccines alone and in combination with cytokines in this Eastern Cooperative Oncology Group multicenter phase II trial.

EXPERIMENTAL DESIGN

Eligible patients were required to have failed prior therapies and to be HLA-A2 positive. Three HLA class I-restricted lineage antigen epitopes were administered in a factorial 2x2 design. Peptide vaccine alone (arm A), or combined with granulocyte-monocyte colony-stimulating factor (GM-CSF; Immunex) 250 microg/d subcutaneously for 14 of 28 days each month (arm B), or combined with IFN-alpha2b (Intron A; Schering-Plough) 10 million units/m2 three times a week (arm C), or combined with both IFN-alpha2b and GM-CSF (arm D). The primary endpoint was immune response measured by enzyme-linked immunospot assay; secondary endpoints were clinical antitumor response, disease-free survival, and overall survival.

RESULTS

One hundred twenty patients enrolled and 115 patients were analyzed. Immune responses to at least one melanoma antigen were observed in 26 of 75 (35%) patients with serial samples. Neither IFN-alpha2b nor GM-CSF significantly improved immune responses. Six objective clinical responses were documented. At a median follow-up of 25.4 months, the median overall survival of patients with vaccine immune response was significantly longer than that of patients with no immune response (21.3 versus 13.4 months; P=0.046).

CONCLUSION

Immune response to vaccination correlates with prolonged survival in patients with metastatic melanoma and is not enhanced by immunomodulatory cytokines as tested in this trial.

A dose-escalation study of aerosolized sargramostim in the treatment of metastatic melanoma: an NCCTG Study

OBJECTIVES

Early testing of aerosolized sargramostim therapy demonstrated anecdotal clinical responses in patients with metastatic melanoma associated with emergence of systemic antitumor immunity. To improve the clinical and immunologic efficacy of therapy without compromising patient safety, we performed a further dose escalation trial in patients with metastatic melanoma.

METHODS

We conducted a dose-escalation clinical trial of HLA-A2 patients with metastatic melanoma to the lung treated with aerosolized granulocyte macrophage colony stimulating factor (GM-CSF) (500-2000 microg/dose, with increments of 250 microg/dose/cohort) twice/d on days 1 to 7 and 15 to 21 every 28 days until progression or severe toxicity to find a dose where a majority of patients develop antitumor immunity. Five patients were treated per each dose level. Clinical, immune, and safety parameters were examined.

RESULTS

The study accrued 40 patients. Toxicity was acceptable. All doses levels were exhausted without identifying a dose of GM-CSF at which a majority of patients (> or =3 of 5) demonstrated significant up-regulation of antitumor immunity. Three of 16 patients who were tetramer positive for at least one melanoma antigen (eg, MART-1) pretreatment developed an immune response (IR) to different tumor antigens. Two of 9 patients who were tetramer negative to all melanoma antigens pretreatment developed an IR against gp100. The greatest changes in antitumor immunity occurred at the highest dose levels.

CONCLUSIONS

A dose of aerosolized GM-CSF capable of inducing antitumor immunity in the majority of patients was not reached. All tested doses were well tolerated. The greatest increase in antitumor T cell IRs was achieved at the highest doses of GM-CSF.

HLA typing demands for peptide-based anti-cancer vaccine

Immunological treatment of cancer has made some very promising advances during the last years. Anti-cancer vaccination using peptides or peptide-pulsed dendritic cells and adoptive transfer of in vitro generated, epitope-specific T cells depend on a well-fitting interaction of HLA molecule and epitope. Accurate HLA-typing is a key factor for successful anti-cancer vaccination. No comprehensive data and no suggestion exist on the HLA-typing in this setting. We performed a systematic review of PubMed analyzing HLA-typing data in cancer vaccination trials over the last 4 years (2004-2007). Then, using the SYFPEITHI database, we calculated the peptide binding prediction of the eight most often used HLA-A*0201 binding epitopes. Finally, high-resolution typing [by sequence-specific primers (SSP)] data of a HLA-A*02 or HLA-A*24 positive population in Berlin, Germany, were analyzed. Forty-five cancer vaccination trials with 764 patients were included. Eighteen studies were performed in the USA, 13 in Europe, 12 in Asia (mainly Japan), and two in Australia. Most common diseases targeted were melanoma, prostate cancer, colorectal cancer, renal cell cancer, and breast cancer. The trials tested protocols using peptide plus adjuvants without DC or protocols using peptide-pulsed DC. In 38 trials (84%) HLA-A2 positive patients were vaccinated, in 11 studies (24%) HLA-A24 positive patients were vaccinated. Nineteen studies with 291 patients (38%) presented the HLA type as four-digit code (high-resolution), 26 studies with 473 patients (62%) presented the HLA-type in a low-resolution code. The method of HLA determination was given in six out of 45 trials (13%). Using the SYFPEITHI database we calculated the peptide binding prediction of the eight most often used HLA-A*0201 binding tumor antigen-derived epitopes for binding to HLA-A*0203. While the epitopes had a binding score of 17-28 for HLA-A*0201, the score for binding to HLA-A*0203 was zero in seven out of eight tested peptides. Only for one peptide the score was eight. Finally, we analyzed high-resolution data of HLA-A*02 and HLA-A*24 positive patients in Berlin, Germany. We found the HLA-A*0201 allele and HLA-A*2402 allele in 95%, respectively. HLA-A*0201 and HLA-A*2402 are most commonly used for peptide based vaccine in cancer. Data on HLA-typing given in the included cancer vaccine manuscripts are fractional. Only 13% report the method of HLA typing and most HLA types are given as low-resolution code. Looking at the binding of specific peptides to both the alleles, it is important to perform high-resolution typing. Further suggestions for immunogenetic laboratories and clinical tumor immunologists regarding HLA-typing for cancer vaccine trials and adoptive T cell transfer approaches are discussed.

Melanoma vaccines

Over the last century, vaccine studies have demonstrated that the human immune system, with appropriate help, can limit or prevent infection against otherwise lethal pathogens. Encouraged by these results, success in animal models and numerous well-documented reports of immune-mediated melanoma regression in humans, investigators developed melanoma vaccines. However, despite considerable laboratory evidence for vaccine-induced immune responses, clinical responses remain poor. Recent studies have elucidated several mechanisms that hinder or prevent the creation of successful vaccines and suggest novel approaches to overcome these barriers. Unraveling the mechanisms of autoimmunity, dendritic cell activation, regulatory T cells and Toll-like receptors will generate novel vaccines that, when used in conjunction with standard adjuvant therapies, may result in improved clinical outcomes. The objective of this review is to provide an overall summary of recent clinical trials with melanoma vaccines and highlight novel vaccine strategies to evaluate in the near future.

Cancer immunotherapy targeting tumour-specific antigens: towards a new therapy for minimal residual disease

BACKGROUND

Clinical investigation of cancer immunotherapy has been very active and several approaches have been evaluated in Phase III trials. In particular, the characterisation at the molecular level of tumour-specific antigens, together with expert knowledge from GSK Biologicals in recombinant protein manufacturing and immunological Adjuvant Systems, has led the company to develop Antigen-Specific Cancer Immunotherapeutic (ASCI).

OBJECTIVE/METHODS

This paper reviews the different cancer immunotherapy approaches that have reached Phase III clinical development. A special attention is given to GSK's ASCI approach.

CONCLUSION

Based on encouraging data in a double-blind Phase II trial in non-small-cell lung cancer, the selection of the most suitable adjuvant system in melanoma and the choice of the adequate clinical setting for the clinical development of cancer immunotherapy, the ASCI approach offers the perspective that the long quest towards a new cancer treatment approach is about to succeed.

Phase III comparison of vitespen, an autologous tumor-derived heat shock protein gp96 peptide complex vaccine, with physician's choice of treatment for stage IV melanoma: the C-100-21 Study Group

PURPOSE

To assess the antitumor activity of vitespen (autologous, tumor- derived heat shock protein gp96 peptide complexes) by determining whether patients with stage IV melanoma treated with vitespen experienced longer overall survival than patients treated with physician's choice.

PATIENTS AND METHODS

Patients (N = 322) were randomly assigned 2:1 to receive vitespen or physician's choice (PC) of a treatment containing one or more of the following: dacarbazine, temozolomide, interleukin-2, or complete tumor resection. This open-label trial was conducted at 71 centers worldwide. Patients were monitored for safety and overall survival.

RESULTS

Therapy with vitespen is devoid of significant toxicity. Patients randomly assigned to the vitespen arm received variable number of injections (range, 0 to 87; median, 6) in part because of the autologous nature of vitespen therapy. Intention-to-treat analysis showed that overall survival in the vitespen arm is statistically indistinguishable from that in the PC arm. Exploratory landmark analyses show that patients in the M1a and M1b substages receiving a larger number of vitespen immunizations survived longer than those receiving fewer such treatments. Such difference was not detected for substage M1c patients.

CONCLUSION

These results are consistent with the immunologic mechanism of action of vitespen, indicating delayed onset of clinical activity after exposure to the vaccine. The results suggest patients with M1a and M1b disease who are able to receive 10 or more doses of vitespen as the candidate population for a confirmatory study.

GSK's antigen-specific cancer immunotherapy programme: pilot results leading to Phase III clinical development

From the first evidence that the immune system could recognize tumors, different types of tumor antigens have been identified and deeply characterized. Several different approaches aimed at targeting these antigens have already been the subject of clinical studies. In this field, the GSK Biologicals' approach relying on recombinant proteins combined with an immunological Adjuvant System in a specific clinical setting, has entertained hopes of developing a new class of well tolerated anti-cancer therapy. This methodology led to promising advances with MAGE-A3 immunotherapy in NSCLC and has the potential to be applied to all tumor types.

More than one reason to rethink the use of peptides in vaccine design

The use of peptides as therapeutics is experiencing renewed enthusiasm owing to advances in delivery, stability and design. Moreover, there is a growing emphasis on the use of peptides in vaccine design as insights into tissue-specific processing of the immunogenic epitopes of proteins and the discovery of unusually long cytotoxic T-lymphocyte epitopes broaden the range of targets and give clues to enhancing peptide immunogenicity. Peptides can also be synthesized with known post-translational modifications and/or deliberately introduced protease-resistant peptide bonds to regulate their processing independent of tissue-specific proteolysis and to stabilize these compounds in vivo. We discuss the potential of peptide-based vaccines for the treatment of chronic viral diseases and cancer, and review recent developments in the field of peptide-based vaccines.

Shared immunoproteome for ovarian cancer diagnostics and immunotherapy: potential theranostic approach to cancer

Elimination of cancer through early detection and treatment is the ultimate goal of cancer research and is especially critical for ovarian and other forms of cancer typically diagnosed at very late stages that have very poor response rates. Proteomics has opened new avenues for the discovery of diagnostic and therapeutic targets. Immunoproteomics, which defines the subset of proteins involved in the immune response, holds considerable promise for providing a better understanding of the early-stage immune response to cancer as well as important insights into antigens that may be suitable for immunotherapy. Early administration of immunotherapeutic vaccines can potentially have profound effects on prevention of metastasis and may potentially cure through efficient and complete tumor elimination. We developed a mass-spectrometry-based method to identify novel autoantibody-based serum biomarkers for the early diagnosis of ovarian cancer that uses native tumor-associated proteins immunoprecipitated by autoantibodies from sera obtained from cancer patients and from cancer-free controls to identify autoantibody signatures that occur at high frequency only in cancer patient sera. Interestingly, we identified a subset of more than 50 autoantigens that were also processed and presented by MHC class I molecules on the surfaces of ovarian cancer cells and thus were common to the two immunological processes of humoral and cell-mediated immunity. These shared autoantigens were highly representative of families of proteins with roles in key processes in carcinogenesis and metastasis, such as cell cycle regulation, cell proliferation, apoptosis, tumor suppression, and cell adhesion. Autoantibodies appearing at the early stages of cancer suggest that this detectable immune response to the developing tumor can be exploited as early-stage biomarkers for the development of ovarian cancer diagnostics. Correspondingly, because the T-cell immune response depends on MHC class I processing and presentation of peptides, proteins that go through this pathway are potential candidates for the development of immunotherapeutics designed to activate a T-cell immune response to cancer. To the best of our knowledge, this is the first comprehensive study that identifies and categorizes proteins that are involved in both humoral and cell-mediated immunity against ovarian cancer, and it may have broad implications for the discovery and selection of theranostic molecular targets for cancer therapeutics and diagnostics in general.

T-Cell Distribution and Adhesion Receptor Expression in Metastatic Melanoma

PURPOSE

Metastatic malignant melanoma is a devastating disease with a poor prognosis. Recent therapeutic trials have focused on immunotherapy to induce development of endogenous antitumor immune responses. To date, such protocols have shown success in activation of tumor-specific CTL but no overall improvement in survival. To kill tumor, antigen-specific CTL must efficiently target and enter tumor tissue. The purpose of this study was to examine the pathway of leukocyte migration to metastatic melanoma.

EXPERIMENTAL DESIGN

Peripheral blood and metastatic melanoma tissues (n = 65) were evaluated for expression of adhesion molecules using immunohistochemistry of tumor sections and flow cytometry of tumor-associated and peripheral blood CTL and compared with healthy controls. CTL expressing T-cell receptors for the melanoma antigen MART-1 were identified in a subset of samples by reactivity with HLA-A2 tetramers loaded with MART-1 peptide.

RESULTS

Results show that the majority of metastatic melanoma samples examined do not express the vascular adhesion receptors E-selectin (CD62E), P-selectin (CD62P), and intercellular adhesion molecule-1 (CD54) on vessels within the tumor boundaries. Strong adhesion receptor expression was noted on vessels within adjacent tissue. Tumor-associated T lymphocytes accumulate preferentially in these adjacent areas and are not enriched for skin- or lymph node-homing receptor phenotype.

CONCLUSION

Expression of leukocyte homing receptors is dysregulated on the vasculature of metastatic melanoma. This results in a block to recruitment of activated tumor-specific CTL to melanoma metastases and is a likely factor limiting the effectiveness of current immunotherapy protocols.

Cancer vaccines in old age

The incidence of cancer has increased over the last decade, mainly due to an increase in the elderly population. Vaccine therapy for cancer is less toxic than chemotherapy or radiation and could be, therefore, especially effective in older, more frail cancer patients. However, it has been shown that older individuals do not respond to vaccine therapy as well as younger adults. This has been attributed to T cell unresponsiveness, a phenomenon also observed in cancer patients per se. This review summarizes the current knowledge of T cell unresponsiveness in cancer patients and elderly, the results of cancer vaccination in preclinical models and in clinical trials, and recent data of cancer vaccination at young and old age in preclinical models. Finally, experimental approaches will be proposed how to make cancer vaccines more effective at older age.

MUC1-specific immune therapy generates a strong anti-tumor response in a MUC1-tolerant colon cancer model

A MUC1-based vaccine was used in a preclinical model of colon cancer. The trial was conducted in a MUC1-tolerant immune competent host injected with MC38 colon cancer cells expressing MUC1. The vaccine included: MHC class I-restricted MUC1 peptides, MHC class II-restricted pan-helper-peptide, unmethylated CpG oligodeoxynucleotide, and granulocyte macrophage-colony stimulating factor. Immunization was successful in breaking MUC1 self-tolerance, and in eliciting a robust anti-tumor response. The vaccine stimulated IFN-gamma-producing CD4(+) helper and CD8(+) cytotoxic T cells against MUC1 and other undefined MC38 tumor antigens. In the prophylactic setting, immunization caused complete rejection of tumor cells, while in the therapeutic regimen, tumor burden was significantly reduced.