From "magic bullets" to specific cancer immunotherapy

The immune system is able to specifically target antigen-expressing cancer cells. The promise of immunotherapy was to eliminate cancer cells without harming normal tissue and, therefore, with no or very few side effects. Immunotherapy approaches have, for several decades, been tested against several tumours, most often against malignant melanoma. However, although detectable immune responses have regularly been induced, the clinical outcome has often been disappointing. The development of molecular methods and an improved understanding of tumour immunosurveillance led to novel immunotherapy approaches in the last few years. First randomised phase III trials proved that immunotherapy can prolong survival of patients with metastatic melanoma or prostate cancer. The development in the field is very rapid and various molecules (mainly monoclonal antibodies) that activate the immune system are currently being tested in clinical trials and will possibly change our treatment of cancer. The ultimate goal of any cancer therapy and also immunotherapy is to cure cancer. However, this depends on the elimination of the disease originating cancer stem cells. Unfortunately, cancer stem cells seem resistant to most available treatment options. Recent developments in immunotherapy may allow targeting these cancer stem cells specifically in the future. In this review, we summarise the current state of immunotherapy in clinical routine and the expected developments in the near future.

Bacillus Calmette-Guérin strain differences have an impact on clinical outcome in bladder cancer immunotherapy

BACKGROUND Whether the commonly used bacillus Calmette-Guérin (BCG) strains Connaught and Tice confer different treatment responses in non-muscle-invasive bladder cancer (NMIBC) is unknown. OBJECTIVES To compare clinical efficacy, immunogenicity, and genetics of BCG Connaught and Tice. DESIGN, SETTING, AND PARTICIPANTS A prospective randomized single-institution trial with treatment of 142 high-risk NMIBC patients with BCG Connaught or Tice. INTERVENTION Patients were randomized to receive six instillations of BCG Connaught or Tice. For experimental studies, BCG strains were compared in C57Bl/6 mice. Bladders and lymphoid tissues were analyzed by cytometry and the latter cultivated to detect live BCG. BCG genomic DNA was sequenced and compared with reference genomes. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS Recurrence-free survival was the primary end point of the clinical study. The Kaplan-Meier estimator was used for estimating survival and time-to-event end points. Nonparametric tests served for the analysis of the in vivo results. RESULTS AND LIMITATIONS Treatment with BCG Connaught conferred significantly greater 5-yr recurrence-free survival compared with treatment with BCG Tice (p=0.0108). Comparable numbers of patients experienced BCG therapy-related side effects in each treatment group (p=0.09). In mice, BCG Connaught induced stronger T-helper cell 1-biased responses, greater priming of BCG-specific CD8(+) T cells, and more robust T-cell recruitment to the bladder than BCG Tice. Genome sequencing of the BCG strains revealed candidate genes potentially involved in the differential clinical responses. CONCLUSIONS BCG strain may have an impact on treatment outcome in NMIBC immunotherapy. PATIENT SUMMARY We compared the efficacy of two commonly used bacillus Calmette-Guérin (BCG) strains for the treatment of NMIBC and found that treatment with BCG Connaught prevented recurrences more efficiently than BCG Tice. Comparison of the immunogenicity of the two strains in mice indicated superior immunogenicity of BCG Connaught. We also identified genetic differences that may explain the differential efficacy of the Connaught and Tice BCG strains. TRIAL REGISTRATION NCT00003779.

Early clinical trial experience with vaccine therapies in non-small-cell lung cancer

Cancer immunotherapy has made great progress because of advances in immunology and molecular biology. Increased understanding of mechanisms by which lung cancer cells escape the immune system and recognition of key tumor antigens and immune system components involved in tumor ignorance have led to the development of a variety of lung cancer vaccines. Immunotherapy has advanced from using nonspecific immunomodulatory agents to lung cancer-specific tumor antigens and tumor cell-derived vaccines. While understanding of immune processes and malignancy has improved, there is great opportunity for further research of vaccine therapies in non-small-cell lung cancer. Herein, we review the development and evolution of early lung cancer vaccine trials.

Decreased tumor surveillance after adoptive T-cell therapy

The effect of cancer immunotherapy on the endogenous immune response against tumors is largely unknown. Therefore, we studied immune responses against murine tumors expressing the glycoprotein (GP) and/or nucleoprotein of lymphocytic choriomeningitis virus (LCMV) with or without adoptive T-cell therapy. In nontreated animals, CTLs specific for different epitopes as well as LCMV-GP-specific antibodies contributed to tumor surveillance. Adoptive immunotherapy with monoclonal CTLs specific for LCMV-gp33 impaired the endogenous tumor-specific antibody and CTL response by targeting antigen cross-presenting cells. As a consequence and in contrast to expectations, immunotherapy enhanced tumor growth. Thus, for certain immunogenic tumors, a reduction of tumor-specific B- and T-cell responses and enhanced tumor growth may be an unwanted consequence of adoptive immunotherapy.

Immunologic response to the survivin-derived multi-epitope vaccine EMD640744 in patients with advanced solid tumors

PURPOSE Survivin is a member of the inhibitor-of-apoptosis family. Essential for tumor cell survival and overexpressed in most cancers, survivin is a promising target for anti-cancer immunotherapy. Immunogenicity has been demonstrated in multiple cancers. Nonetheless, few clinical trials have demonstrated survivin-vaccine-induced immune responses. EXPERIMENTAL DESIGN This phase I trial was conducted to test whether vaccine EMD640744, a cocktail of five HLA class I-binding survivin peptides in Montanide(®) ISA 51 VG, promotes anti-survivin T-cell responses in patients with solid cancers. The primary objective was to compare immunologic efficacy of EMD640744 at doses of 30, 100, and 300 μg. Secondary objectives included safety, tolerability, and clinical efficacy. RESULTS In total, 49 patients who received ≥2 EMD640744 injections with available baseline- and ≥1 post-vaccination samples [immunologic-diagnostic (ID)-intention-to-treat] were analyzed by ELISpot- and peptide/MHC-multimer staining, revealing vaccine-activated peptide-specific T-cell responses in 31 patients (63 %). This cohort included the per study protocol relevant ID population for the primary objective, i.e., T-cell responses by ELISpot in 17 weeks following first vaccination, as well as subjects who discontinued the study before week 17 but showed responses to the treatment. No dose-dependent effects were observed. In the majority of patients (61 %), anti-survivin responses were detected only after vaccination, providing evidence for de novo induction. Best overall tumor response was stable disease (28 %). EMD640744 was well tolerated; local injection-site reactions constituted the most frequent adverse event. CONCLUSIONS Vaccination with EMD640744 elicited T-cell responses against survivin peptides in the majority of patients, demonstrating the immunologic efficacy of EMD640744.

Intravital and whole-organ imaging reveals capture of melanoma-derived antigen by lymph node subcapsular macrophages leading to widespread deposition on follicular dendritic cells.

Aberrant antigens expressed by tumor cells, such as in melanoma, are often associated with humoral immune responses, which may in turn influence tumor progression. Despite recent data showing the central role of adaptive immune responses on cancer spread or control, it remains poorly understood where and how tumor-derived antigen (TDA) induces a humoral immune response in tumor-bearing hosts. Based on our observation of TDA accumulation in B cell areas of lymph nodes (LNs) from melanoma patients, we developed a pre-metastatic B16.F10 melanoma model expressing a fluorescent fusion protein, tandem dimer tomato, as a surrogate TDA. Using intravital two-photon microscopy (2PM) and whole-mount 3D LN imaging of tumor-draining LNs in immunocompetent mice, we report an unexpectedly widespread accumulation of TDA on follicular dendritic cells (FDCs), which were dynamically scanned by circulating B cells. Furthermore, 2PM imaging identified macrophages located in the subcapsular sinus of tumor-draining LNs to capture subcellular TDA-containing particles arriving in afferent lymph. As a consequence, depletion of macrophages or genetic ablation of B cells and FDCs resulted in dramatically reduced TDA capture in tumor-draining LNs. In sum, we identified a major pathway for the induction of humoral responses in a melanoma model, which may be exploitable to manipulate anti-TDA antibody production during cancer immunotherapy.

Preexisting BCG-specific T cells improve intravesical immunotherapy for bladder cancer

Therapeutic intravesical instillation of bacillus Calmette-Guérin (BCG) is effective at triggering inflammation and eliciting successful tumor immunity in patients with non-muscle invasive bladder cancer, with 50 to 70% clinical response. Therapeutic success relies on repeated instillations of live BCG administered as adjuvant therapy shortly after tumor resection; however, the precise mechanisms remain unclear. Using an experimental model, we demonstrate that after a single instillation, BCG could disseminate to bladder draining lymph nodes and prime interferon-γ-producing T cells. Nonetheless, repeated instillations with live BCG were necessary for a robust T cell infiltration into the bladder. Parenteral exposure to BCG before instillation overcame this requirement; after the first intravesical instillation, BCG triggered a more robust acute inflammatory process and accelerated T cell entry into the bladder, as compared to the standard protocol. Moreover, parenteral exposure to BCG before intravesical treatment of an orthotopic tumor markedly improved response to therapy. Indeed, patients with sustained preexisting immunity to BCG showed a significant improvement in recurrence-free survival. Together, these data suggest that monitoring patients' response to purified protein derivative, and, in their absence, boosting BCG responses by parenteral exposure before intravesical treatment initiation, may be a safe and effective means of improving intravesical BCG-induced clinical responses.

Efficiency of recombinant human TNF in human cancer therapy

Recombinant human tumour necrosis factor (TNF) has a selective effect on angiogenic vessels in tumours. Given that it induces vasoplegia, its clinical use has been limited to administration through isolated limb perfusion (ILP) for regionally advanced melanomas and soft tissue sarcomas of the limbs. When combined with the alkylating agent melphalan, a single ILP produces a very high objective response rate. In melanoma, the complete response (CR) rate is around 80% and the overall objective response rate greater than 90%. In soft tissue sarcomas that are inextirpable, ILP is a neoadjuvant treatment resulting in limb salvage in 80% of the cases. The CR rate averages 20% and the objective response rate is around 80%. The mode of action of TNF-based ILP involves two distinct and successive effects on the tumour-associated vasculature: first, an increase in endothelium permeability leading to improved chemotherapy penetration within the tumour tissue, and second, a selective killing of angiogenic endothelial cells resulting in tumour vessel destruction. The mechanism whereby these events occur involves rapid (of the order of minutes) perturbation of cell-cell adhesive junctions and inhibition of alphavbeta3 integrin signalling in tumour-associated vessels, followed by massive death of endothelial cells and tumour vascular collapse 24 hours later. New, promising approaches for the systemic use of TNF in cancer therapy include TNF targeting by means of single chain antibodies or endothelial cell ligands, or combined administration with drugs perturbing integrin-dependent signalling and sensitizing angiogenic endothelial cells to TNF-induced death.

Influence of natural killer cells and perforin-mediated cytolysis on the development of chemically induced lung cancer in A/J mice

One alternative approach for the treatment of lung cancer might be the activation of the immune system using vaccination strategies. However, most of clinical vaccination trials for lung cancer did not reach their primary end points, suggesting that lung cancer is of low immunogenicity. To provide additional experimental information about this important issue, we investigated which type of immune cells contributes to the protection from lung cancer development. Therefore, A/J mice induced for lung adenomas/adenocarcinomas by the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) were depleted of CD4(+) or CD8(+) T cells, CD11b(+) macrophages, Gr-1(+) neutrophils and asialo GM1(+) natural killer (NK) cells. Subsequent analysis of tumour growth showed an increase in tumour number only in mice depleted of NK cells. Further asking by which mechanism NK cells suppressed tumour development, we neutralized several death ligands of the tumour necrosis factor (TNF) family known to be involved in NK cell-mediated cytotoxicity. However, neither depletion of TNF-α, TNF-related apoptosis-inducing ligand, TNF-like weak inducer of apoptosis or FasL alone nor in combination induced an augmentation of tumour burden. To show whether an alternative cell death pathway is involved, we next generated A/J mice deficient for perforin. After challenging with NNK, mice deficient for perforin showed an increase in tumour number and volume compared to wild-type A/J mice. In summary, our data suggest that NK cells and perforin-mediated cytolysis are critically involved in the protection from lung cancer giving promise for further immunotherapeutic strategies for this disease.

Cancer intelligence acquired (CIA): tumor glycosylation and sialylation codes dismantling antitumor defense

Aberrant glycosylation is a key feature of malignant transformation and reflects epigenetic and genetic anomalies among the multitude of molecules involved in glycan biosynthesis. Although glycan biosynthesis is not template bound, altered tumor glycosylation is not random, but associated with common glycosylation patterns. Evidence suggests that acquisition of distinct glycosylation patterns evolves from a ‘microevolutionary’ process conferring advantages in terms of tumor growth, tumor dissemination, and immune escape. Such glycosylation modifications also involve xeno- and hypersialylation. Xeno-autoantigens such as Neu5Gc-gangliosides provide potential targets for immunotherapy. Hypersialylation may display ‘enhanced self’ to escape immunosurveillance and involves several not mutually exclusive inhibitory pathways that all rely on protein–glycan interactions. A better understanding of tumor ‘glycan codes’ as deciphered by lectins, such as siglecs, selectins, C-type lectins and galectins, may lead to novel treatment strategies, not only in cancer, but also in autoimmune disease or transplantation.

Clinical Perspectives from Randomized Phase 3 Trials on Prostate Cancer: An Analysis of the ClinicalTrials.gov Database

AbstractBackground It is not easy to overview pending phase 3 trials on prostate cancer (PCa), and awareness of these trials would benefit clinicians. Objective To identify all phase 3 trials on {PCa} registered in the ClinicalTrials.gov database with pending results. Design and setting On September 29, 2014, a database was established from the records for 175 538 clinical trials registered on ClinicalTrials.gov. A search of this database for the substring “prostat” identified 2951 prostate trials. Phase 3 trials accounted for 441 studies, of which 333 concerned only PCa. We selected only ongoing or completed trials with pending results, that is, for which the primary endpoint had not been published in a peer-reviewed medical journal. Results and limitations We identified 123 phase 3 trials with pending results. Trials were conducted predominantly in North America (n = 63; 51) and Europe (n = 47; 38). The majority were on nonmetastatic disease (n = 82; 67), with 37 (30) on metastatic disease and four trials (3) including both. In terms of intervention, systemic treatment was most commonly tested (n = 71; 58), followed by local treatment 34 (28), and both systemic and local treatment (n = 11; 9), with seven (6) trials not classifiable. The 71 trials on systemic treatment included androgen deprivation therapy (n = 34; 48), chemotherapy (n = 15; 21), immunotherapy (n = 9; 13), other systemic drugs (n = 9; 13), radiopharmaceuticals (n = 2; 3), and combinations (n = 2; 3). Local treatments tested included radiation therapy (n = 27; 79), surgery (n = 5; 15), and both (n = 2; 2). A limitation is that not every clinical trial is registered on ClinicalTrials.gov. Conclusion There are many {PCa} phase 3 trials with pending results, most of which address questions regarding systemic treatments for both nonmetastatic and metastatic disease. Radiation therapy and androgen deprivation therapy are the interventions most commonly tested for local and systemic treatment, respectively. Patient summary This report describes all phase 3 trials on prostate cancer registered in the ClinicalTrials.gov database with pending results. Most of these trials address questions regarding systemic treatments for both nonmetastatic and metastatic disease. Radiation therapy and androgen deprivation therapy are the interventions most commonly tested for local and systemic treatment, respectively.

Tumor infiltrating lymphocytes in ovarian cancer.

Several improvements in ovarian cancer treatment have been achieved in recent years, both in surgery and in combination chemotherapy with targeting. However, ovarian tumors remain the women's cancers with highest mortality rates. In this scenario, a pivotal role has been endorsed to the immunological environment and to the immunological mechanisms involved in ovarian cancer behavior. Recent evidence suggests a loss of the critical balance between immune-activating and immune-suppressing mechanisms when oncogenesis and cancer progression occur. Ovarian cancer generates a mechanism to escape the immune system by producing a highly suppressive environment. Immune-activated tumor infiltrating lymphocytes (TILs) in ovarian tumor tissue testify that the immune system is the trigger in this neoplasm. The TIL mileau has been demonstrated to be associated with better prognosis, more chemosensitivity, and more cases of optimal residual tumor achieved during primary cytoreduction. Nowadays, scientists are focusing attention on new immunologically effective tumor biomarkers in order to optimize selection of patients for recruitment in clinical trials and to identify relationships of these biomarkers with responses to immunotherapeutics. Assessing this point of view, TILs might be considered as a potent predictive immunotherapy biomarker.