Skin tests predict survival after autologous tumor cell vaccination in metastatic melanoma: experience in 81 patients

Advanced Oxidation Nanoprocessing Boosts Immunogenicity of Whole Tumor Cells

Whole tumor cells expressing a wide array of tumor antigens are considered as a highly promising source of antigens for cancer vaccines. However, simultaneously preserving the antigen diversity, improving immunogenicity, and eliminating the potential tumorigenic risk of whole tumor cells are highly challenging. Inspired by the recent progress in sulfate radical-based environmental technology, herein, an advanced oxidation nanoprocessing (AONP) strategy is developed for boosting the immunogenicity of whole tumor cells. The AONP is based on the activation of peroxymonosulfate by ZIF-67 nanocatalysts to produce SO4 -∙ radicals continuously, leading to sustained oxidative damage to tumor cells and consequently extensive cell death. Importantly, AONP causes immunogenic apoptosis as evidenced by the release of a series of characteristic damage associated molecular patterns and at the same time maintains the integrity of cancer cells, which is critical to preserve the cellular components and thus maximize the diversity of antigens. Finally, the immunogenicity of AONP-treated whole tumor cells is evaluated in a prophylactic vaccination model, demonstrating significantly delayed tumor growth and increased survival rate of live tumor-cell-challenged mice. It is expected that the developed AONP strategy would pave the way to develop effective personalized whole tumor cell vaccines in future.

Biomimetic and bioinspired nano-platforms for cancer vaccine development

The advent of immunotherapy has revolutionized the treating modalities of cancer. Cancer vaccine, aiming to harness the host immune system to induce a tumor-specific killing effect, holds great promises for its broad patient coverage, high safety, and combination potentials. Despite promising, the clinical translation of cancer vaccines faces obstacles including the lack of potency, limited options of tumor antigens and adjuvants, and immunosuppressive tumor microenvironment. Biomimetic and bioinspired nanotechnology provides new impetus for the designing concepts of cancer vaccines. Through mimicking the stealth coating, pathogen recognition pattern, tissue tropism of pathogen, and other irreplaceable properties from nature, biomimetic and bioinspired cancer vaccines could gain functions such as longstanding, targeting, self-adjuvanting, and on-demand cargo release. The specific behavior and endogenous molecules of each type of living entity (cell or microorganism) offer unique features to cancer vaccines to address specific needs for immunotherapy. In this review, the strategies inspired by eukaryotic cells, bacteria, and viruses will be overviewed for advancing cancer vaccine development. Our insights into the future cancer vaccine development will be shared at the end for expediting the clinical translation.

CD169 Defines Activated CD14+ Monocytes With Enhanced CD8+ T Cell Activation Capacity

Monocytes are antigen-presenting cells (APCs) that play diverse roles in promoting or regulating inflammatory responses, but their role in T cell stimulation is not well defined. In inflammatory conditions, monocytes frequently show increased expression of CD169/Siglec-1, a type-I interferon (IFN-I)-regulated protein. However, little is known about the phenotype and function of these CD169⁺ monocytes. Here, we have investigated the phenotype of human CD169⁺ monocytes in different diseases, their capacity to activate CD8⁺ T cells, and the potential for a targeted-vaccination approach. Using spectral flow cytometry, we detected CD169 expression by CD14⁺ CD16^- classical and CD14⁺ CD16⁺ intermediate monocytes and unbiased analysis showed that they were distinct from dendritic cells, including the recently described CD14-expressing DC3. CD169⁺ monocytes expressed higher levels of co-stimulatory and HLA molecules, suggesting an increased activation state. IFNα treatment highly upregulated CD169 expression on CD14⁺ monocytes and boosted their capacity to cross-present antigen to CD8⁺ T cells. Furthermore, we observed CD169⁺ monocytes in virally-infected patients, including in the blood and bronchoalveolar lavage fluid of COVID-19 patients, as well as in the blood of patients with different types of cancers. Finally, we evaluated two CD169-targeting nanovaccine platforms, antibody-based and liposome-based, and we showed that CD169⁺ monocytes efficiently presented tumor-associated peptides gp100 and WT1 to antigen-specific CD8⁺ T cells. In conclusion, our data indicate that CD169⁺ monocytes are activated monocytes with enhanced CD8⁺ T cell stimulatory capacity and that they emerge as an interesting target in nanovaccine strategies, because of their presence in health and different diseases.

Tumor-mediated inhibition of human dendritic cell differentiation and function is consistently counteracted by combined p38 MAPK and STAT3 inhibition

Targeting dendritic cells (DC) through the release of suppressive factors is an effective means for tumors to escape immune control. We assessed the involvement of downstream signaling through the JAK2/STAT3 and p38 MAPK pathways in tumor-induced suppression of human DC development. Whereas the JAK2/STAT3 pathway has been pinpointed in mouse studies as a key regulator of myeloid suppression, in human DC this is less well established. We studied the effects of STAT3 inhibition on the suppression of monocyte-derived DC differentiation mediated by a short-list of four predominant suppressive factors and found that pharmacological STAT3 inhibition could only counteract the effects of IL-6. Accordingly, in testing a panel of supernatants derived from 11 cell lines representing various types of solid tumors, STAT3 inhibition only modestly affected the suppressive effects of a minority of supernatants. Importantly, combined interference in the STAT3 and p38 pathways completely prevented inhibition of DC differentiation by all tested supernatants and effected superior DC function, evidenced by increased allogeneic T cell reactivity with elevated IL-12p70/IL-10 ratios and Th1 skewing. Combined STAT3 and p38 inhibition also afforded superior protection against the suppressive effects of primary glioma and melanoma supernatants and induced a shift from CD14⁺ cells to CD1a⁺ cells in metastatic melanoma single-cell suspensions, indicating a potential for improved DC differentiation in the tumor microenvironment. We conclude that combined interference in the STAT3 and p38 MAPK signaling pathways is a promising approach to overcome tumor-induced inhibitory signaling in DC precursors and will likely support clinical immunotherapeutic strategies.

Selective tumor antigen vaccine delivery to human CD169+ antigen-presenting cells using ganglioside-liposomes

Priming of CD8+ T cells by dendritic cells (DCs) is crucial for the generation of effective antitumor immune responses. Here, we describe a liposomal vaccine carrier that delivers tumor antigens to human CD169/Siglec-1+ antigen-presenting cells using gangliosides as targeting ligands. Ganglioside-liposomes specifically bound to CD169 and were internalized by in vitro-generated monocyte-derived DCs (moDCs) and macrophages and by ex vivo-isolated splenic macrophages in a CD169-dependent manner. In blood, high-dimensional reduction analysis revealed that ganglioside-liposomes specifically targeted CD14+ CD169+ monocytes and Axl+ CD169+ DCs. Liposomal codelivery of tumor antigen and Toll-like receptor ligand to CD169+ moDCs and Axl+ CD169+ DCs led to cytokine production and robust cross-presentation and activation of tumor antigen-specific CD8+ T cells. Finally, Axl+ CD169+ DCs were present in cancer patients and efficiently captured ganglioside-liposomes. Our findings demonstrate a nanovaccine platform targeting CD169+ DCs to drive antitumor T cell responses.

Safety and efficacy of autologous tumour cell vaccines as a cancer therapeutic to treat solid tumours and haematological malignancies: a meta-analysis protocol for two systematic reviews

INTRODUCTION

Autologous cancer cell vaccines are promising personalised immunotherapeutic options for solid and haematological malignancies that uses the patient's own cells to arm an immune response. Evidence suggests that among patients receiving these vaccines, those who mount an immune response against their own tumour cells have better prognosis, and a myriad of preclinical studies have demonstrated the same. Recently, two autologous cell vaccines Vigil and OncoVAX have made it to phase III clinical trials. Here, we outline a protocol to be used for two separate systematic reviews using a parallel approach for inclusion criteria, data extraction and analysis for autologous cell vaccines in (1) solid and (2) haematological malignancies. We aim to review evidence from controlled and uncontrolled interventional studies of autologous cell vaccines administered to patients with cancer to determine their historical efficacy (with or without associated adjuvants or modifications) with clinical response rates and safety outcomes being of particular importance.

METHODS AND ANALYSIS

We will search MEDLINE (OVID interface, including In-Process and Epub Ahead of Print), Embase (OVID interface) and the Cochrane Central Register of Controlled Trials (Wiley interface) for articles published from 1947 until 30 July 2018 (date search was performed). Studies will be screened first by title and abstract, then by full-text in duplicate. Interventional trials that report the use of an autologous cell vaccine to patients with cancer of any age will be included. The primary outcomes of interest in this review are clinical response (complete or overall/objective response) and safety outcomes (adverse events). Secondary outcomes include immune response, disease-free survival and overall survival. The risk of bias within studies will be assessed using the appropriate Cochrane Risk of Bias tool. If appropriate, a random effects meta-analysis will be performed to synthesise the data and report summary estimates of effect. Statistical heterogeneity will be assessed using the I2 statistic.

ETHICS AND DISSEMINATION

Ethics approval is not required for this systematic review protocol as the review will solely use published literature. Results will be submitted to peer-reviewed journals for publication and presented to relevant stakeholders and scientific meetings.

PROSPERO REGISTRATION NUMBER

CRD42019140187.

Autologous tumor cell vaccination combined with systemic CpG-B and IFN-α promotes immune activation and induces clinical responses in patients with metastatic renal cell carcinoma: a phase II trial

Background

In this study the toxicity and efficacy of an irradiated autologous tumor cell vaccine (ATV) co-injected with a class-B CpG oligodeoxynucleotide (CpG-B) and GM-CSF, followed by systemic CpG-B and IFN-α administration, were examined in patients with metastatic renal cell carcinoma (mRCC).

Methods

A single-arm Phase II trial was conducted, in which patients with mRCC were intradermally injected with a minimum of three whole-cell vaccines containing 0.7–1.3 × 107 irradiated autologous tumor cells (ATC), admixed with 1 mg CpG-B and 100 µg GM-CSF, followed by bi-weekly s.c. injections with 8 mg CpG-B and s.c. injections with 6 MU IFN-α three times per week.

Results

Fifteen patients were treated according to the protocol. Treatment was well tolerated. Objective clinical responses occurred in three patients, including one long-term complete response. Disease stabilization occurred in another three patients. Positive delayed type hypersensitivity (DTH) responses to ATC were absent before treatment but present in 13 out of 15 patients during treatment. Immune monitoring revealed activation of plasmacytoid dendritic cells, non-classical monocytes and up-regulation of both PD-1 and CTLA4 on effector T cells upon treatment. Moreover, a pre-existing ex vivo IFN-γ response to ATC was associated with clinical response.

Conclusions

ATV combined with systemic CpG-B and IFN-α is tolerable, safe, immunogenic and able to elicit anti-tumor responses in patients with mRCC. Immune activation and treatment-induced up-regulation of PD-1 and CTLA4 on circulating T cells further suggest an added benefit of combining this approach with immune checkpoint blockade [added]

Results of a Pilot Trial of Immunotherapy with Dendritic Cells Pulsed with Autologous Tumor Lysates in Patients with Advanced Cancer

Aims and background

The purpose of the study was to test the immunological and clinical effects of infusions of dendritic cells pulsed with autologous tumor lysate in patients with advanced cancer.

Patients and methods

Peripheral blood mononuclear cells from 15 patients with metastatic cancer (melanoma in 10, lung cancer in 2, renal cell carcinoma in 1, sarcoma in 1, breast cancer in 1) were harvested by leukapheresis after mobilization with GM-CSF (5 μg/kg/day s.c. for 4 days). Mononuclear cells were separated and cultured in GM-CSF (1000 U/ml) and interleukin-4 (1000 U/ml) for 7 days. Phenotype was assessed by 2-color flow cytometry and immunocytochemistry. On day 6, dendritic cells were pulsed with 1 g of fresh autologous tumor lysate for 24 h and infused intravenously. Interleukin-2 (6 million IU), interferon a (4 million IU) and GM-CSF (400 μg) were injected s.c. daily for 10 days beginning on the day of dendritic cell infusion. Treatment was repeated every 21 days for 3 courses.

Results

The morphology, immunocytochemistry and phenotype of cultured cells was consistent with dendritic cells: intense positivity for HLA-DR and CD86, with negativity for markers of other lineages, including CD3, CD4, CD8 and CD14. More than 5 × 107 dendritic cells were injected in all patients. Nine patients developed >5 mm delayed type cutaneous hypersensitivity reactions to tumor lysate ± GM-CSF after the first immunization (larger than GM-CSF in all cases). Median delayed type cutaneous hypersensitivity to lysate + GM-CSF was 3 cm after the third immunization. One melanoma patient with skin, liver, lung and bone metastases had a partial response lasting 8 months (followed by progression in the brain). Seven patients had stable disease for >3 months, and 7 had progression.

Conclusions

Infusion of tumor lysate-pulsed dendritic cells induces a strong cell-mediated antitumor immune reaction in patients with advanced cancer and has some clinical activity.

Immunotherapy with subcutaneous immunogenic autologous tumor lysate increases murine glioblastoma survival

Immunotherapeutic strategies for glioblastoma, the most frequent malignant primary brain tumor, aim to improve its disastrous consequences. On top of the standard treatment, one strategy uses T cell activation by autologous dendritic cells (DC) ex vivo loaded with tumor lysate to attack remaining cancer cells. Wondering whether 'targeting' in vivo DCs could replace these ex vivo ones, immunogenic autologous tumor lysate was used to treat glioma-inoculated mice in the absence of ex vivo loaded DCs. Potential immune mechanisms were studied in two orthotopic, immunocompetent murine glioma models. Pre-tumoral subcutaneous lysate treatment resulted in a survival benefit comparable to subcutaneous DC therapy. Focussing on the immune response, glioma T cell infiltration was observed in parallel with decreased amounts of regulatory T cells. Moreover, these results were accompanied by the presence of strong tumor-specific immunological memory, shown by complete survival of a second glioblastoma tumor, inoculated 100 days after the first one. Finally, in combination with temozolomide, survival of established glioma in mice could be increased. Our results show the potential of immunogenic autologous tumor lysate used to treat murine glioblastoma, which will be worthwhile to study in clinical trials as it has potential as a cost-efficient adjuvant treatment strategy for gliomas.

Adjuvant Autologous Melanoma Vaccine for Macroscopic Stage III Disease: Survival, Biomarkers, and Improved Response to CTLA-4 Blockade

Background. There is not yet an agreed adjuvant treatment for melanoma patients with American Joint Committee on Cancer stages III B and C. We report administration of an autologous melanoma vaccine to prevent disease recurrence. Patients and Methods. 126 patients received eight doses of irradiated autologous melanoma cells conjugated to dinitrophenyl and mixed with BCG. Delayed type hypersensitivity (DTH) response to unmodified melanoma cells was determined on the vaccine days 5 and 8. Gene expression analysis was performed on 35 tumors from patients with good or poor survival. Results. Median overall survival was 88 months with a 5-year survival of 54%. Patients attaining a strong DTH response had a significantly better (p = 0.0001) 5-year overall survival of 75% compared with 44% in patients without a strong response. Gene expression array linked a 50-gene signature to prognosis, including a cluster of four cancer testis antigens: CTAG2 (NY-ESO-2), MAGEA1, SSX1, and SSX4. Thirty-five patients, who received an autologous vaccine, followed by ipilimumab for progressive disease, had a significantly improved 3-year survival of 46% compared with 19% in nonvaccinated patients treated with ipilimumab alone (p = 0.007). Conclusion. Improved survival in patients attaining a strong DTH and increased response rate with subsequent ipilimumab suggests that the autologous vaccine confers protective immunity.

Antigen-specific vaccines for cancer treatment

Vaccines targeting pathogens are generally effective and protective because based on foreign non-self antigens which are extremely potent in eliciting an immune response. On the contrary, efficacy of therapeutic cancer vaccines is still disappointing. One of the major reasons for such poor outcome, among others, is the difficulty of identifying tumor-specific target antigens which should be unique to the tumors or, at least, overexpressed on the tumors as compared to normal cells. Indeed, this is the only option to overcome the peripheral immune tolerance and elicit a non toxic immune response. New and more potent strategies are now available to identify specific tumor-associated antigens for development of cancer vaccine approaches aiming at eliciting targeted anti-tumor cellular responses. In the last years this aspect has been addressed and many therapeutic vaccination strategies based on either whole tumor cells or specific antigens have been and are being currently evaluated in clinical trials. This review summarizes the current state of cancer vaccines, mainly focusing on antigen-specific approaches.

Whole Tumor Antigen Vaccines: Where Are We?

With its vast amount of uncharacterized and characterized T cell epitopes available for activating CD4⁺ T helper and CD8⁺ cytotoxic lymphocytes simultaneously, whole tumor antigen represents an attractive alternative source of antigens as compared to tumor-derived peptides and full-length recombinant tumor proteins for dendritic cell (DC)-based immunotherapy. Unlike defined tumor-derived peptides and proteins, whole tumor lysate therapy is applicable to all patients regardless of their HLA type. DCs are essentially the master regulators of immune response, and are the most potent antigen-presenting cell population for priming and activating naïve T cells to target tumors. Because of these unique properties, numerous DC-based immunotherapies have been initiated in the clinics. In this review, we describe the different types of whole tumor antigens that we could use to pulse DCs ex vivo and in vivo. We also discuss the different routes of delivering whole tumor antigens to DCs in vivo and activating them with toll-like receptor agonists.

Functional characterization of a STAT3-dependent dendritic cell-derived CD14+ cell population arising upon IL-10-driven maturation

Interleukin (IL)-10 is a major cancer-related immunosuppressive factor, exhibiting a unique ability to hamper the maturation of dendritic cells (DCs). We have previously reported that IL-10 induces the conversion of activated, migratory CD1a⁺ DCs found in the human skin to CD14⁺CD141⁺ macrophage-like cells. Here, as a model of tumor-conditioned DC maturation, we functionally assessed CD14^- and CD14⁺ DCs that matured in vitro upon exposure to IL-10. IL-10-induced CD14⁺ DCs were phenotypically characterized by a low maturation state as well as by high levels of BDCA3 and DC-SIGN, and as such they closely resembled CD14⁺ cells infiltrating melanoma metastases. Compared with DC matured under standard conditions, CD14⁺ DCs were found to express high levels of B7-H1 on the cell surface, to secrete low levels of IL-12p70, to preferentially induce TH2 cells, to have a lower allogeneic TH cell and tumor antigen-specific CD8⁺ T-cell priming capacity and to induce proliferative T-cell anergy. In contrast to their CD14⁺ counterparts, CD14^- monocyte-derived DCs retained allogeneic TH priming capacity but induced a functionally anergic state as they completely abolished the release of effector cytokines. Transcriptional and cytokine release profiling studies indicated a more profound angiogenic and pro-invasive signature of CD14⁺ DCs as compared with DCs matured in standard conditions or CD14⁻ DCs matured in the presence of IL-10. Importantly, signal transducer and activator of transcription 3 (STAT3) depletion by RNA interference prevented the development of the IL-10-associated CD14⁺ phenotype, allowing for normal DC maturation and providing a potential means of therapeutic intervention.

TLR agonists: our best frenemy in cancer immunotherapy

Various TLR agonists are currently under investigation in clinical trials for their ability to orchestrate antitumor immunity. The antitumor responses are largely attributed to their aptitude to stimulate APCs such as DCs which in turn, activate tumor-specific T cell responses. However, there is a potential for TLR signaling to occur on cells other than professional APCs that could negate antitumor responses or even worse, promote tumor growth. The impetus for this review is twofold. First, there is accumulating data demonstrating that the engagement of TLRs on different T cell subsets and different cancer types could promote tumor growth or conversely, contribute to antitumor responses. Second, the efficacy of TLR agonists as monotherapies to treat cancer patients has been limited. In this review, we discuss how TLR signaling within different T cell subsets and cancer cells can potentially impact the generation of antitumor responses. Based on evidence from preclinical models and clinical trials, we draw attention to several criteria that we believe must be considered when selecting TLR agonists for developing effective immunotherapeutic strategies against cancer.

Is a pacific coexistence between virus and host the unexploited path that may lead to an HIV functional cure?

The SupT1 cell line supports optimal HIV-1 replication, and prolonged in vitro replication in SupT1 cells renders the virus significantly less virulent. This raises the question of whether the infusion of SupT1 cells could be used as a cell-based therapy to induce a pacific coexistence between the HIV virus and its human host. In a recent study, I investigated this potential therapeutic strategy in vitro. The results suggested that this approach should be further explored in HIV-susceptible animal models. Such studies may lead to the development of a functional cure for HIV infection.

IL-21 promotes the expansion of CD27+ CD28+ tumor infiltrating lymphocytes with high cytotoxic potential and low collateral expansion of regulatory T cells

Background

Adoptive cell transfer of tumor infiltrating lymphocytes has shown clinical efficacy in the treatment of melanoma and is now also being explored in other tumor types. Generation of sufficient numbers of effector T cells requires extensive ex vivo expansion, often at the cost of T cell differentiation and potency. For the past 20 years, IL-2 has been the key cytokine applied in the expansion of TIL for ACT. However, the use of IL-2 has also led to collateral expansion of regulatory T cells (Tregs) and progressive T cell differentiation, factors known to limit in vivo persistence and activity of transferred TIL. The use of alternative T cell growth factors is therefore warranted. Here, we have compared the effects of IL-2, -15 and −21 cytokines on the expansion and activation of TIL from single-cell suspensions of non-small cell lung cancer, ovarian cancer and melanoma.

Methods

We applied the K562-based artificial APC (aAPC) platform for the direct and rapid expansion of tumor infiltrating lymphocytes isolated from primary cancer specimens. These aAPC were engineered to express the Fc-γ receptor CD32 (for anti-CD3 antibody binding), the co-stimulatory molecule 4-1BBL, and to secrete either IL-2, IL-15 or IL-21 cytokine.

Results

Although IL-2 aAPC induced the greatest overall TIL expansion, IL-21 aAPC induced superior expansion of CD8⁺ T cells with a CD27⁺CD28⁺ “young” phenotype and superior functional cytotoxic effector characteristics, without collateral expansion of Tregs.

Conclusion

Our data rationalize the clinical application of IL-21-secreting aAPC as a standardized cell-based platform in the expansion of “young” effector TIL for ACT.

Selected anti-tumor vaccines merit a place in multimodal tumor therapies

Multimodal approaches are nowadays successfully applied in cancer therapy. Primary locally acting therapies such as radiotherapy (RT) and surgery are combined with systemic administration of chemotherapeutics. Nevertheless, the therapy of cancer is still a big challenge in medicine. The treatments often fail to induce long-lasting anti-tumor responses. Tumor recurrences and metastases result. Immunotherapies are therefore ideal adjuncts to standard tumor therapies since they aim to activate the patient's immune system against malignant cells even outside the primary treatment areas (abscopal effects). Especially cancer vaccines may have the potential both to train the immune system against cancer cells and to generate an immunological memory, resulting in long-lasting anti-tumor effects. However, despite promising results in phase I and II studies, most of the concepts finally failed. There are some critical aspects in development and application of cancer vaccines that may decide on their efficiency. The time point and frequency of medication, usage of an adequate immune adjuvant, the vaccine's immunogenic potential, and the tumor burden of the patient are crucial. Whole tumor cell vaccines have advantages compared to peptide-based ones since a variety of tumor antigens (TAs) are present. The master requirements of cell-based, therapeutic tumor vaccines are the complete inactivation of the tumor cells and the increase of their immunogenicity. Since the latter is highly connected with the cell death modality, the inactivation procedure of the tumor cell material may significantly influence the vaccine's efficiency. We therefore also introduce high hydrostatic pressure (HHP) as an innovative inactivation technology for tumor cell-based vaccines and outline that HHP efficiently inactivates tumor cells by enhancing their immunogenicity. Finally studies are presented proving that anti-tumor immune responses can be triggered by combining RT with selected immune therapies.

Cancer peptide vaccine therapy developed from oncoantigens identified through genome-wide expression profile analysis for bladder cancer

OBJECTIVE

The field of cancer vaccine therapy is currently expected to become the fourth option in the treatment of cancer after surgery, chemotherapy and radiation therapy. We developed a novel cancer peptide vaccine therapy for bladder cancer through a genome-wide expression profile analysis.

METHODS

Among a number of oncoproteins that are transactivated in cancer cells, we focused on M phase phosphoprotein 1 and DEP domain containing 1, both of which are cancer-testis antigens playing critical roles in the growth of bladder cancer cells, as candidate molecules for the development of drugs for bladder cancer. In an attempt to identify the peptide epitope from these oncoantigens, we conducted a clinical trial using these peptides for patients with advanced bladder cancer.

RESULTS

We identified HLA-A24-restricted peptide epitopes corresponding to parts of M phase phosphoprotein 1 and DEP domain containing 1 proteins, which could induce peptide-specific cytotoxic T lymphocytes. Using these peptides, we found that M phase phosphoprotein 1- and DEP domain containing 1-derived peptide vaccines could be well tolerated without any serious adverse events, and effectively induced peptide-specific cytotoxic T lymphocytes in vivo.

CONCLUSIONS

The novel approach adopted in the treatment with peptide vaccines is considered to be a promising therapy for bladder cancer.

Adjuvants for enhancing the immunogenicity of whole tumor cell vaccines

Whole tumor cell lysates can serve as excellent multivalent vaccines for priming tumor-specific CD8(+) and CD4(+) T cells. Whole cell vaccines can be prepared with hypochlorous acid oxidation, UVB-irradiation and repeat cycles of freeze and thaw. One major obstacle to successful immunotherapy is breaking self-tolerance to tumor antigens. Clinically approved adjuvants, including Montanide™ ISA-51 and 720, and keyhole-limpet proteins can be used to enhance tumor cell immunogenicity by stimulating both humoral and cellular anti-tumor responses. Other potential adjuvants, such as Toll-like receptor agonists (e.g., CpG, MPLA and PolyI:C), and cytokines (e.g., granulocyte-macrophage colony stimulating factor), have also been investigated.

Immunologic biomarkers as correlates of clinical response to cancer immunotherapy

Over the last few years, several newly developed immune-based cancer therapies have been shown to induce clinical responses in significant numbers of patients. As a result, there is a need to identify immune biomarkers capable of predicting clinical response. If there were laboratory parameters that could define patients with improved disease outcomes after immunomodulation, product development would accelerate, optimization of existing immune-based treatments would be facilitated and patient selection for specific interventions might be optimized. Although there are no validated cancer immunologic biomarkers that are predictive of clinical response currently in widespread use, there is much published literature that has informed investigators as to which markers may be the most promising. Population-based studies of endogenous tumor immune infiltrates and gene expression analyses have identified specific cell populations and phenotypes of immune cells that are most likely to mediate anti-tumor immunity. Further, clinical trials of cancer vaccines and other cancer directed immunotherapy have identified candidate immunologic biomarkers that are statistically associated with beneficial clinical outcomes after immune-based cancer therapies. Biomarkers that measure the magnitude of the Type I immune response generated with immune therapy, epitope spreading, and autoimmunity are readily detected in the peripheral blood and, in clinical trials of cancer immunotherapy, have been associated with response to treatment.

Translating tumor antigens into cancer vaccines

Vaccines represent a strategic successful tool used to prevent or contain diseases with high morbidity and/or mortality. However, while vaccines have proven to be effective in combating pathogenic microorganisms, based on the immune recognition of these foreign antigens, vaccines aimed at inducing effective antitumor activity are still unsatisfactory. Nevertheless, the effectiveness of the two licensed cancer-preventive vaccines targeting tumor-associated viral agents (anti-HBV [hepatitis B virus], to prevent HBV-associated hepatocellular carcinoma, and anti-HPV [human papillomavirus], to prevent HPV-associated cervical carcinoma), along with the recent FDA approval of sipuleucel-T (for the therapeutic treatment of prostate cancer), represents a significant advancement in the field of cancer vaccines and a boost for new studies in the field. Specific active immunotherapies based on anticancer vaccines represent, indeed, a field in continuous evolution and expansion. Significant improvements may result from the selection of the appropriate tumor-specific target antigen (to overcome the peripheral immune tolerance) and/or the development of immunization strategies effective at inducing a protective immune response. This review aims to describe the vast spectrum of tumor antigens and strategies to develop cancer vaccines.

Whole tumor antigen vaccines

Although cancer vaccines with defined antigens are commonly used, the use of whole tumor cell preparations in tumor immunotherapy is a very promising approach and can obviate some important limitations in vaccine development. Whole tumor cells are a good source of TAAs and can induce simultaneous CTLs and CD4(+) T helper cell activation. We review current approaches to prepare whole tumor cell vaccines, including traditional methods of freeze-thaw lysates, tumor cells treated with ultraviolet irradiation, and RNA electroporation, along with more recent methods to increase tumor cell immunogenicity with HOCl oxidation or infection with replication-incompetent herpes simplex virus.

Depression, cortisol, and suppressed cell-mediated immunity in metastatic breast cancer

Cancer treatment is known to have significant immuno-suppressive/dysregulatory effects. Psychological distress and depression, which often accompany cancer diagnosis and treatment, can also suppress or dysregulate endocrine and immune function. Cell-mediated immunity (CMI) is critical for protection against a host of pathogens to which cancer patients may be particularly susceptible. CMI is also important for defense against some tumors. This study explored relationships among depressive symptoms, cortisol secretion, and CMI responses in 72 women with metastatic breast cancer. Depressive symptoms were assessed with the Center for Epidemiologic Studies-Depression Scale (CES-D). Saliva was sampled throughout the day over a 3-day period to obtain a physiologic index of diurnal cortisol concentrations and rhythmicity, which is associated with breast cancer survival time. CMI for specific antigens was measured following intradermal administration of seven commonly encountered antigens (tuberculin, tetanus, diphtheria, Streptococcus, Candida, Trichophyton, and Proteus). Analyses adjusting for relevant medical and treatment variables indicated that women reporting more depressive symptoms showed suppressed immunity as measured by lower average induration size. Women with higher mean diurnal cortisol concentrations also showed suppressed immunity as indicated by a decreased number of antigens to which positive reactions were measured. This study highlights the relationships among depression, stress, and immune function in the context of advanced breast cancer.

Overview of Tumor Cell–Based Vaccines

Whole-cell tumor vaccines have been investigated for more than 20 years for their efficacy in both preclinical models and in clinical trials in humans. There are clear advantages of whole-cell/polyepitope vaccination over those types of immunotherapy that target specific epitopes. Multiple and unknown antigens may be targeted to both the innate and adaptive immune system, and this may be further augmented by genetic modification of the vaccine cells to provide cytokines and costimulation. In this review, we give an overview of the field including the preclinical and clinical advances using unmodified and modified tumor-cell vaccines.

Recent advances in cancer vaccines: an overview

The field of cancer vaccines is currently in an active state of clinical investigations. Human papilloma virus vaccine has been approved as a prophylactic cancer vaccine, while Oncophage (heat shock protein-peptide complex) was recently approved in Russia for a certain stage of kidney cancer, although to date none has been approved in Japan or the USA. We reviewed recent clinical trials of several different types of cancer vaccines, mainly by using PubMed from 2005 to 2008. There have been slow but substantial advances in peptide vaccines and dendritic cell-based vaccines with regard to both clinical responses and immunological markers. A personalized approach to boost immune responses, addition of chemotherapy to overcome robust cancers and changing of endpoints from tumor reduction to overall survival seem to be the three key elements for the development of therapeutic cancer vaccines.

Whole-cell cancer vaccination: from autologous to allogeneic tumor- and dendritic cell-based vaccines

The field of tumor vaccination is currently undergoing a shift in focus, from individualized tailor-made vaccines to more generally applicable vaccine formulations. Although primarily predicated by financial and logistic considerations, stemming from a growing awareness that clinical development for wide-scale application can only be achieved through backing from major pharmaceutical companies, these new approaches are also supported by a growing knowledge of the intricacies and minutiae of antigen presentation and effector T-cell activation. Here, the development of whole-cell tumor and dendritic cell (DC)-based vaccines from an individualized autologous set-up to a more widely applicable allogeneic approach will be discussed as reflected by translational studies carried out over the past two decades at our laboratories and clinics in the vrije universiteit medical center (VUmc) in Amsterdam, The Netherlands.

A novel murine model of allogeneic vaccination against prostate cancer

Prostate cancer continues to be a major cause of death in men. Surgical and medical treatments of the disease have improved, but metastasic disease remains a significant clinical problem. Novel therapies such as whole cell vaccination offer the potential of treating disease by stimulating the immune system. To study the efficacy of a whole cell vaccine in prostate cancer two strains of mice were used: C57BL/6 (H-2Kb) and C3H/HeJ (H-2K(k)) in combination with four different cell lines. Thus, a model was constructed of allogeneic and syngeneic vaccine, as well as a challenge tumour for each strain. Two novel cell lines were developed during this study. Firstly, the non tumourigeneic PMC-1 was derived from a normal mouse prostate and immortalized with HPV16. Secondly, the tumourigeneic PMC-1 C6ras1p1 was transformed with human ras gene which formed tumours in both SCID and C3H/HeJ mice. Protection, and the nature of the immune response to syngeneic and allogeneic vaccine, in males and females was examined in both strains. Vaccination with both syngeneic and allogeneic irradiated whole cell vaccines induced protection from syngeneic challenge in females. However, no protection was observed when allogeneic vaccine was given to male mice. This correlated with the immune response. Two types of cellular immune responses were generated in females. A NK-mediated response was observed in C57BL/6 mice, whilst C3H/HeJ mice developed a CTL response. Little or no cellular immune response was observed in males. The cytokine profile in C3H/HeJ females was a mixture of Th1 and Th2 whilst a mainly Th1 profile was observed in C57BL/6 mice. Male mice showed a diminished cytokine secretion compared to females which was further depressed after challenge. The difference in immunity was largely as expected, since tolerance to prostate antigens should not normally develop in female mice. However, this makes this model particularly relevant clinically since it directly mimics the human situation and thus may accelerate the development of whole cell vaccines for clinical use.

A phase I clinical study of vaccination of melanoma patients with dendritic cells loaded with allogeneic apoptotic/necrotic melanoma cells. Analysis of toxicity and immune response to the vaccine and of IL-10 -1082 promoter genotype as predictor of disease progression

BACKGROUND

Sixteen melanoma patients (1 stage IIC, 8 stage III, and 7 stage IV) were treated in a Phase I study with a vaccine (DC/Apo-Nec) composed of autologous dendritic cells (DCs) loaded with a mixture of apoptotic/necrotic allogeneic melanoma cell lines (Apo-Nec), to evaluate toxicity and immune responses. Also, IL-10 1082 genotype was analyzed in an effort to predict disease progression.

METHODS

PBMC were obtained after leukapheresis and DCs were generated from monocytes cultured in the presence of GM-CSF and IL-4 in serum-free medium. Immature DCs were loaded with gamma-irradiated Apo-Nec cells and injected id without adjuvant. Cohorts of four patients were given four vaccines each with 5, 10, 15, or 20 x 106 DC/Apo-Nec cell per vaccine, two weeks apart. Immune responses were measured by ELISpot and tetramer analysis. Il-10 genotype was measured by PCR and corroborated by IL-10 production by stimulated PBMC.

RESULTS

Immature DCs efficiently phagocytosed melanoma Apo-Nec cells and matured after phagocytosis as evidenced by increased expression of CD83, CD80, CD86, HLA class I and II, and 75.2 +/- 16% reduction in Dextran-FITC endocytosis. CCR7 was also up-regulated upon Apo-Nec uptake in DCs from all patients, and accordingly DC/Apo-Nec cells were able to migrate in vitro toward MIP-3 beta. The vaccine was well tolerated in all patients. The DTH score increased significantly in all patients after the first vaccination (Mann-Whitney Test, p < 0.05). The presence of CD8+T lymphocytes specific to gp100 and Melan A/MART-1 Ags was determined by ELISpot and tetramer analysis in five HLA-A*0201 patients before and after vaccination; one patient had stable elevated levels before and after vaccination; two increased their CD8 + levels, one had stable moderate and one had negligible levels. The analysis of IL-10 promoter -1082 polymorphism in the sixteen patients showed a positive correlation between AA genotype, accompanied by lower in vitro IL-10 production by stimulated PBMC, and faster melanoma progression after lymph nodes surgery (p = 0.04). With a mean follow-up of 49.5 months post-surgery, one stage IIC patient and 7/8 stage III patients remain NED but 7/7 stage IV patients have progressed.

CONCLUSION

We conclude that DC/Apo-Nec vaccine is safe, well tolerated and it may induce specific immunity against melanoma Ags. Patients with a low-producing IL-10 polymorphism appear to have a worst prognosis.

TRIAL REGISTRATION

Clinicaltrials.gov (NHI) NCT00515983.

Induction of dendritic cell-mediated immune responses against canine malignant melanoma cells

To establish the basis for the use of dendritic cells (DC) in the treatment of canine melanoma, dogs were vaccinated using autologous DC pulsed with canine melanoma CMM2 cell lysate in the presence of keyhole limpet haemocyanin (KLH) in vitro (CMM2-KLH-DC), and the induction of immune responses against CMM2 cells in vivo was examined using the delayed-type hypersensitivity (DTH) skin test. The DTH responses against CMM2 cells and KLH were observed in dogs vaccinated with CMM2-KLH-DC, while the responses against KLH but not CMM2 cells were detected with DC pulsed with KLH alone (KLH-DC). Recruitment of CD8 and CD4 T cells was detected in the positively responding sites, suggested that vaccination with CMM2-KLH-DC efficiently elicits T cell-mediated immunity against CMM-2 cells in vivo. These findings demonstrate the potential utility of DC-based tumour vaccination in the treatment of canine malignant melanoma.

Vaccine therapy for melanoma: current status and future directions

A vaccine is typically defined as any preparation used as a preventive inoculation to confer immunity against a specific disease. Vaccines for infectious diseases are highly effective, acting by inducing antigen-specific immunity that prevents subsequent infection. Unfortunately, the success of vaccines in infectious diseases has not been mirrored in oncology. This failure is the result of several challenges facing cancer vaccines, including the conceptual shift from disease prevention to disease treatment, tumor-induced immunosuppression and other mechanisms of immune escape, the similarity between tumor antigens and self antigens to which the patient is tolerant, unfavorable effector-to-target ratios in patients with established tumors, and financial and regulatory issues. Despite this, cancer remains a promising target for vaccine therapy. Melanoma in particular is known for its inherent immunogenicity on the basis of many anecdotal reports of spontaneous immune-based tumor regression, and thus has been the focus of immunotherapeutic approaches. Rare but significant vaccine-induced clinical regression of melanoma has spurred intensive investigations to augment vaccine efficacy. This review explores the many vaccine strategies that have been clinically tested for the treatment of melanoma and considers future approaches of cancer immunotherapy.

A Phase I Study of an Allogeneic Cell Vaccine (VACCIMEL) With GM-CSF in Melanoma Patients

We investigated whether recombinant human granulocyte-monocyte-colony-stimulating factor (rhGM-CSF) increased the immunogenicity of VACCIMEL, a vaccine consisting of 3 irradiated allogeneic melanoma cell lines. A phase I clinical trial was performed on 20 melanoma patients in stages IIB (n=2), III (n=10), and IV (n=8), who were disease free after surgery (n=16) or had minimal disease (n=4). Cohorts of 4 patients were vaccinated 4 times with VACCIMEL and bacillus Calmette Guerin (BCG) as adjuvant. Besides, the patients received placebo (group 1) or GM-CSF: 150 microg (group 2), 300 microg (group 3), 400 microg (group 4), and 600 microg (group 5) per vaccine. The combination of VACCIMEL and GM-CSF had low toxicity. Only in group 5, grade 2 thoracic pain (3/4 patients) and abdominal cramps (2/4 patients) were observed. Delayed-type hypersensitivity increased after vaccination and it was highest in group 4. Phytohemagglutinin stimulation of peripheral blood lymphocytes was analyzed in 9 patients: 4/9 had normal stimulation; 3/9 had low basal stimulation, which recovered after vaccination; and 2/9 were not stimulated. Antimelanoma antibodies preexisted in 9/19 patients; in 3/19 patients, antibodies anti-33 kd, 90 kd, and 100 kd antigens were induced by vaccination. IgG2 but not IgG1 antibodies were detected. Anti-BCG antibodies, mostly IgG2, reached the highest post/prevaccination ratio in group 4. Median serum interleukin-12 was lower in progressing patients (61.6 pg/mL) than in those without evident disease (89 pg/mL). Thus, its low toxicity and the induction of a predominantly cellular immune response suggest that the addition of 300 to 400 microg GM-CSF to VACCIMEL is useful in increasing the immune response.

Melanoma-specific tumor-infiltrating lymphocytes but not circulating melanoma-specific T cells may predict survival in resected advanced-stage melanoma patients

PURPOSE

To study the effect of autologous tumor cell vaccinations on the presence and numbers of circulating CD8+ T cells specific for tumor-associated antigens (TAA) in metastatic melanoma patients. To investigate the correlation between the presence of tumor-infiltrating lymphocytes (TIL) and circulating TAA-specific CD8+ T cells before and after autologous tumor cell vaccination with overall survival.

EXPERIMENTAL DESIGN

Twenty-five stage III and resected stage IV metastatic melanoma patients were adjuvantly treated with a series of intracutaneously injected autologous tumor cell vaccinations, of which the first two contained BCG as an immunostimulatory adjuvant. Tumor samples and blood samples obtained before and after vaccination of these patients were studied for the presence of TAA-specific T cells using HLA-tetramers and results were correlated with survival.

RESULTS

In 5 of 17 (29%) melanoma patients, circulating TAA-specific T cells were detectable prior to immunizations. No significant changes in the frequency and specificity were found during the treatment period in all patients. Presence of circulating TAA-specific T cells was not correlated with survival (log rank, P=0.215). Inside melanoma tissue, TAA-specific TIL could be detected in 75% of 16 available tumor samples. In case of detectable TAA-specific TIL, median survival was 22.5 months compared to median survival of 4.5 months in case of absence of TAA-specific T cells (log rank, P=0.0094). In none of the patients, TAA-specific T cells were found both in tumor tissue and blood at the same time.

CONCLUSIONS

These data suggest that the presence of TAA-specific TILs forms a prognostic factor, predicting improved survival in advanced-stage melanoma patients. The absence of TAA-specific T cells in the circulation suggests that homing of the tumor-specific T cell population to the tumor site contributes to the effectiveness of antitumor immunity.

Expression of the apoptosis inhibitor protease inhibitor 9 predicts clinical outcome in vaccinated patients with stage III and IV melanoma

PURPOSE

There have been reports of successful treatment of metastatic melanoma patients with active specific immunotherapy (ASI) using irradiated autologous tumor cell vaccination. It is still unknown why some patients respond and others do not. Tumor cells can evade the immune system, for example through interference with antigen presentation by down-regulation of MHC molecules or expressing proteins interfering with cytotoxic lymphocyte-induced apoptosis like the granzyme B antagonist protease inhibitor 9 (PI-9).

EXPERIMENTAL DESIGN

PI-9 expression was detected in melanoma cell lines. To investigated if PI-9 is important in the response to ASI, paraffin-embedded tissues from stage III or IV melanoma patients were stained.

RESULTS

PI-9 is expressed in melanoma cells and expression in metastasized melanoma cells is, in this group of patients, an adverse prognostic marker with regard to overall and disease-free survival. Moreover, loss of MHC-1 expression frequently occurs during tumor progression but is not associated with poor clinical outcome. Interestingly, melanoma patients with a favorable clinical outcome after ASI therapy usually have high percentages of activated (granzyme B-positive) tumor-infiltrating lymphocytes at time of first diagnosis and low percentages of activated lymphocytes at time of recurrent tumor.

CONCLUSIONS

Expression of PI-9 in metastatic melanoma cells is associated with unfavorable clinical outcome whereas MHC-1 down-regulation is not. Although it cannot be proven that PI-9 expression is directly responsible for failure of immunotherapy, these data suggest that expression of PI-9 could be an important immune escape mechanism and that modulation of this inhibitor may enhance the efficacy of immunotherapy.

Active specific immunotherapy in colon cancer

Colorectal cancer is one of the leading causes of cancer-related mortality. After a series of clinical trials, the adjuvant 5-FU-based chemotherapy has established a definitive role in the management of stage III colon cancer. While the precise role for chemotherapy in stage II disease remains under investigation, less toxic treatment modalities such as active specific immunotherapy (ASI) have emerged as potentially attractive alternatives. In a randomized trial it was demonstrated that ASI, using autologous tumor cells and BCG, had a significant clinical benefit in the adjuvant treatment of stage II colon cancer. In addition, it was found that the delayed-type cutaneous hypersensitivity reactions (DTH) against autologous cells correlated significantly with survival, confirming its suitability for immunomonitoring. Nowadays, 5-FU-based chemotherapy is a standard treatment for stage III colon cancer and because there is preclinical evidence for synergism between chemotherapy and ASI, we performed a phase II study to investigate whether the combined treatment with 5-FU and ASI is tolerable and feasible. We demonstrated that 5-FU treatment hardly affected the DTH response against autologous tumor cells and that the combination treatment was well tolerated. A randomized phase III trial is now warranted to show that the combination of ASI and chemotherapy is superior to chemotherapy alone.

Interleukin-2 improves tumour response to DNP-modified autologous vaccine for the treatment of metastatic malignant melanoma

This paper is a report of response rate (RR) and survival of 34 metastatic melanoma patients who received a dinitrophenyl (DNP)-modified autologous melanoma cell vaccine. In all, 27 patients started the vaccine as a primary treatment for metastatic melanoma and seven started it as an adjuvant, with no evidence of disease at the time, but had developed new metastases. Interleukin-2 (IL-2) was administered in 24 out of the 34 patients: 19 who progressed on vaccine alone and five who had the combination from start. Interleukin-2 was administered in the intravenous, bolus high-dose regimen (seven patients) or as subcutaneous (s.c.) low-dose treatment (17). Overall response for the entire group was 35% (12 patients out of 34), 12% having a complete response (CR) and 23% a partial response (PR). However, only two patients had tumour responses while on the vaccine alone, whereas the other 10 demonstrated objective tumour regression following the combination with IL-2 (two CR, eight PR), lasting for a median duration of 6 months (range 3–50 months). Of the 12 responding patients, 11 attained strong skin reactivity to the s.c. injection of irradiated, unmodified autologous melanoma cells. None of the patients with a negative reactivity experienced any tumour response. Patients with positive skin reactions survived longer (median survival – 54 months). The results suggest enhanced RRs to the combination of IL-2 and autologous melanoma vaccine. Skin reactivity to unmodified autologous melanoma cells may be a predictor of response and improved survival, and therefore a criterion for further pursuing of immunotherapeutic strategies.

Immunological properties of trehalose dimycolate (cord factor) and other mycolic acid-containing glycolipids--a review

Mycolic acids are characteristic fatty acids of Mycobacteria and are responsible for the wax-like consistence of these microorganisms. Decades of research revealed that mycolic acid-containing glycolipids, in particular trehalose-6,6'-dimycolate (TDM, cord factor) as their best-studied representative, exert a number of immunomodifying effects. They are able to stimulate innate, early adaptive and both humoral and cellular adaptive immunity. Most functions can be associated with their ability to induce a wide range of chemokines (MCP-1, MIP-1alpha, IL-8) and cytokines (e.g., IL-12, IFN-gamma, TNF-alpha, IL-4, IL-6, IL-10). This review tries to link well-known properties of mycolic acid-containing glycolipids, e.g., stimulation of cellular and humoral immunity, granuloma formation and anti-tumor activity, with recent findings in molecular immunology and to give an outlook on potential practical applications.

Autologous cell vaccine as a post operative adjuvant treatment for high-risk melanoma patients (AJCC stages III and IV). The new American Joint Committee on Cancer

This study evaluates the overall survival and disease free survival of melanoma patients that were treated with an autologous melanoma cell vaccine, administered as a post-operative adjuvant. Included are 43 patients with totally resected metastatic melanoma (28-AJCC stage III, 15-AJCC stage IV), with a median follow up of 34 months (6-62). The treatment consisted of eight doses of a vaccine made of 10-25x10(6) autologous melanoma cells either released from the surgical specimen or grown in cell cultures. Tumour cells were conjugated with hapten dinitrophenyl, mixed with Bacille Calmette Guérin and irradiated to 110 Gy. Both disease free survival and overall survival were found to be correlated with intensity of evolving delayed type hypersensitivity to subcutaneous injection of unmodified melanoma cells. Patients with a delayed type hypersensitivity reaction of > or =10 mm had a median disease free survival of 17 months (mean 35 months) and a mean overall survival of 63 months (median not reached). In contrast, patients with a negative or weak delayed type hypersensitivity had a median disease free survival of 9 months (relative risk of recurrence=4.5, P=0.001), and a median overall survival of 16 months (relative risk of death=15, P=0.001). Stage III patients with a positive delayed type hypersensitivity reaction had an improved disease free survival of 16 months and a mean overall survival of 38 months, whereas patients with a negative delayed type hypersensitivity had a median disease free survival of 7 months (relative risk=4.5, P=0.02) and a median overall survival of 16 months (relative risk=9.5, P=0.005). The adjuvant administration of autologous melanoma vaccine was associated with improved disease-free and overall survival to selected patients who successfully attained anti-melanoma reactivity as detected by positive delayed type hypersensitivity reactions to unmodified melanoma cells.

A phase II study of active specific immunotherapy and 5-FU/Leucovorin as adjuvant therapy for stage III colon carcinoma

Active specific immunotherapy, using vaccines with autologous tumour cells and BCG, significantly reduces the rate of tumour recurrence in stage II colon cancer patients, while no clinical benefit has yet been observed in stage III patients. Adjuvant treatment with 5-Fluorouracil/Leucovorin is now considered standard therapy for stage III colon carcinoma and results in an absolute survival benefit of approximately 10%. Yet, the 5-year overall survival rate of stage III colon cancer patients is only 40-50%. Combining chemotherapy and immunotherapy might improve prognosis for stage III patients, especially when considering that active specific immunotherapy and chemotherapy have shown synergistic effects in pre-clinical tumour models. We performed a phase II study with 56 patients, using the combination of active specific immunotherapy and chemotherapy as an adjuvant therapy in stage III colon cancer patients to assess the influence of 5-Fluorouracil/Leucovorin on anti-tumour immunity induced by autologous tumour cell vaccinations. Anti-tumour immunity was measured before and after chemotherapy by means of delayed type hypersensitivity reactions, taken 48 h after the third and the fourth vaccination. We also investigated the toxicity of this combined immuno-chemotherapy treatment. Delayed type hypersensitivity reactions before chemotherapy had a median size of 20.3 mm, while after chemotherapy delayed type hypersensitivity size was 18.4 mm (P=0.01), indicating that chemotherapy hardly affected anti-tumour immunity. The severity of ulcers at the BCG vaccination sites was comparable to previous studies. In 30% of the patients grade III or grade IV chemotherapy related toxicity was seen; this is comparable to what is normally observed after adjuvant chemotherapy alone. This study shows that the active specific immunotherapy-induced anti-tumour immune response is only minimally impaired by consecutive chemotherapy and that the combined treatment of stage III colon cancer patients with active specific immunotherapy and 5-Fluorouracil/Leucovorin does not cause unexpected toxicity.

Tumour cell-based vaccines for the treatment of melanoma

Melanoma is generally resistant to chemotherapy and radiation therapy. Its unique immunological properties lend support to developing innovative new therapies via manipulation of the patient's own immune system. The use of whole-cell-based tumour vaccines, including autologous, whole-cell allogeneic and cytokine gene-modified vaccines, as well as tumour lysate vaccines, for active specific immunotherapy of melanoma, is discussed in detail with regard to rationale and available clinical data. Although phase II data on the use of melanoma vaccine in the adjuvant setting show promise, there is no randomised phase III trial demonstrating the efficacy of active specific immunotherapy for melanoma. The coming years will bring the results of several pivotal multicentre phase III trials testing the clinical utility of active specific immunotherapy in the management of melanoma.