Phase 1 trial of allogeneic gene-modified tumor cell vaccine RCC-26/CD80/IL-2 in patients with metastatic renal cell carcinoma

Combining the past and present to advance immuno-radiotherapy of cancer

Since its first clinical application, 120 years ago, radiotherapy evolved into a major anti-cancer treatment modality, offering high cure rates in many human malignancies. During the past ten years, the establishment of immune checkpoint inhibitors (ICIs) in cancer therapeutics has vigorously reintroduced the immune system's role in the outcome of radiotherapy and, conversely, the role of radio-vaccination in the efficacy of immunotherapy. The knowledge and clinical experience that founded the current era of immuno-radiotherapy started alongside with the birth of radiotherapy, and evolved through exhaustive experimental work, clinical trials on active specific immunotherapy, frustrating attempts to validate the importance of cytokine administration with radiotherapy, and, finally, the encouraging ICI-based clinical trials that opened the door to a far more encouraging perspective; radio-vaccination, through its old and new methods, is rising as a research field that promises to cure, previously incurable, disease. In this critical review, we focus on the scientific knowledge gathered through more than a century of research on radiotherapy interactions with the immune system. Understanding the origins of this promising therapeutic approach will substantially contribute to developing new immuno-radiotherapy policies in the fight against cancer.

New treatment modalities with vaccine therapy in renal cell carcinoma

The aim of implementing vaccine therapy is to activate immune response against malignant cells by overcoming the tolerance triggered by the tumor. These treatments are effective using the immune response against cancer. Not every type of cancer is suitable for vaccine therapies. For a vaccine therapy to be implemented, cancer should be immunogenic and contain tissue-specific proteins, should have a slow progression, and treatments should be feasible. For that reason, studies regarding urological cancers are mostly focused on the kidneys and the prostate. Vaccine therapies used in renal cell carcinoma (RCC) can be categorized under the following titles: autologous tumor cells, dendritic cells, genetically modified tumor cells, and protein/peptide. Although there are old studies on the implementation of vaccine therapies in RCC, researches have only been intensified recently. In addition to their effective potential for lengthening general survival, decreasing tumor burden and cancer development in long term, vaccine treatments are especially effective in metastatic RCC patients. We think that vaccine treatments would be applied more in near future since RCC are immunogenic. In this compilation, we will discuss vaccine therapies used in RCC, which urologists are not so familiar with, in the light of the up-to-date literature.

Identification of patient-specific and tumor-shared T cell receptor sequences in renal cell carcinoma patients

A major requirement for cancer immunotherapy is the development of biomarkers for prognosis and for monitoring therapy response. In an attempt to evaluate the immune response of renal cell carcinoma (RCC) patients, tumor lesions and / or blood samples from 12 RCC patients underwent deep T cell receptor (TCR) sequencing. Despite the low number of samples, different TCR distribution patterns could be detected. Most of the RCC patients presented "patient-specific" TCR sequences, and those clonotypes were present at higher frequency in tumor lesions suggesting a specific extravasation from the blood. Comparison among the tumor samples revealed also "patient-shared" TCR patterns. Indeed, a central core of 16 different TCRs were shared by 3 patients, whereas other 6 patients shared between 4 and 6 TCR sequences, with two sub-groups sharing 12 to 17 different clonotypes. The relative frequencies of shared clonotypes were very different varying from < 1% to a maximum of 37% of the total TCR repertoire. These data confirm the presence of tumor-specific TCR within the cancer tissue and suggest the existence of shared epitopes among different patients that might be used as targets for tumor immunotherapy.

Allogeneic partially HLA-matched dendritic cells pulsed with autologous tumor cell lysate as a vaccine in metastatic renal cell cancer: a clinical phase I/II study

Multi-kinase inhibitors have been established for the treatment of advanced renal cell cancer, but long-term results are still disappointing and immunotherapeutic approaches remain an interesting experimental option particularly in patients with a low tumor burden. DC are crucial for antigen-specific MHC-restricted T cell immunity. Furthermore, allogeneic HLA-molecules pose a strong immunogenic signal and may help to induce tumor-specific T cell responses. In this phase I/II trial, 7 patients with histologically confirmed progressive metastatic RCC were immunized repetitively with 1 × 10 (7) allogeneic partially HLA-matched DC pulsed with autologous tumor lysate following a schedule of 8 vaccinations over 20 weeks. Patients also received 3 Mio IE IL-2 s.c. once daily starting in week 4. Primary endpoints of the study were feasibility and safety. Secondary endpoints were immunological and clinical responses. Vaccination was feasible and safe with no severe toxicity being observed. No objective response could be documented. However, while all patients had documented progress at study entry, 29% of the patients showed SD throughout the study with a mean TTP of 24.6 weeks (range 5 to 96 weeks). In 3/7 patients, TH1-polarized immune responses against RCC-associated antigens were observed. In one patient showing a minimal clinical response and a TTP of 96 weeks, clonally proliferated T cells against yet undefined antigens were induced by the vaccine. Vaccination with tumor antigen loaded DC remains an interesting experimental approach, but should rather be applied in the situation of minimal residual disease after systemic therapy. Additional depletion of regulatory cells might be a promising strategy.

High immune response rates and decreased frequencies of regulatory T cells in metastatic renal cell carcinoma patients after tumor cell vaccination

Our previously reported phase I clinical trial with the allogeneic gene-modified tumor cell line RCC-26/CD80/IL-2 showed that vaccination was well tolerated and feasible in metastatic renal cell carcinoma (RCC) patients. Substantial disease stabilization was observed in most patients despite a high tumor burden at study entry. To investigate alterations in immune responses that might contribute to this effect, we performed an extended immune monitoring that included analysis of reactivity against multiple antigens, cytokine/chemokine changes in serum and determination of the frequencies of immune suppressor cell populations, including natural regulatory T cells (nTregs) and myeloid-derived suppressor cell subsets (MDSCs). An overall immune response capacity to virus-derived control peptides was present in 100% of patients before vaccination. Vaccine-induced immune responses to tumor-associated antigens occurred in 75% of patients, demonstrating the potent immune stimulatory capacity of this generic vaccine. Furthermore, some patients reacted to peptide epitopes of antigens not expressed by the vaccine, showing that epitope-spreading occurred in vivo. Frequencies of nTregs and MDSCs were comparable to healthy donors at the beginning of study. A significant decrease of nTregs was detected after vaccination (p = 0.012). High immune response rates, decreased frequencies of nTregs and a mixed T helper 1/T helper 2 (T(H)1/T(H)2)-like cytokine pattern support the applicability of this RCC generic vaccine for use in combination therapies.

Hodgkin's lymphoma RNA-transfected dendritic cells induce cancer/testis antigen-specific immune responses

Cytotoxic T lymphocytes (CTL) can kill Hodgkin's lymphoma (HL) cells, and CTL have been used for the treatment of Epstein-Barr virus (EBV)-positive HL. For patients with EBV-negative HL, this strategy cannot be employed and alternative target structures have to be defined. In order to establish a system for the stimulation of HL-reactive T cells, we used dendritic cells (DC) as antigen-presenting cells for autologous T cells and transfected these DC with RNA from established HL cell lines. After stimulation of peripheral blood mononuclear cells (PBMC) with RNA-transfected DC, we analyzed the reactivity of primed PBMC by interferon gamma enzyme-linked immunospot. Our results suggest the presence of antigens with expression in HL cell lines and recognition of these antigens in combination with DC-derived human leukocyte antigen molecules. By the analysis of Gene Expression Omnibus microarray data sets from HL cell lines and primary HL samples in comparison with testis and other normal tissues, we identified HL-associated cancer testis antigens (CTA) including the preferentially expressed antigen in melanoma (PRAME). After stimulation of PBMC with RNA-transfected DC, we detected PRAME-reactive T cells. PRAME and other HL-associated CTA might be targets for HL-specific immune therapy or for the monitoring of HL-directed immune responses.

Autologous versus allogeneic cell-based vaccines?

Devitalized tumor cells either autologous or allogeneic have been used as anti-cancer vaccines with the purpose of facilitating the induction of an immune response able to destroy growing tumor cells since the identification of tumor antigens was deemed not to be necessary, particularly in the autologous system. Such vaccines were tested first in animal models and then in the clinics as unmodified tumor cells or after insertion of genes coding for factors known to increase the immune response against tumors. These vaccines were usually given by subcutaneous injections along with different immunological adjuvants. Such immunization approaches were found to be effective in mice when carried out in a tumor preventive setting but significantly less in the therapeutic context, that is, in the presence of an established tumor. By analyzing several clinical trials of vaccination using either autologous or allogeneic unmodified and gene-modified tumor cells published in the last 10 to 15 years, we conclude for a lack of sufficient evidence for efficacy of this strategy in inducing both a strong immune response and a therapeutic response. A potential variant of this strategy is the direct intratumoral injection of immunostimulatory genes delivered by vectors in vivo. But even this approach failed to provide a statistically significant clinical benefit for the cancer patients.We also point out the inherent drawbacks of the tumor cell-based vaccine strategy that include (a) a limited frequency by which human tumor lines can be obtained from clinical samples, (b) the low number of available cells for vaccination, (c) the release of immune-suppressive factors by tumor cells, and (d) the cost and time necessary for standardization and collecting/expanding a number of cells according to the approved regulatory requirements. Thus, taking into consideration the new developments in cancer vaccines, we believe that tumor cell-based vaccines should be dismissed as anti-cancer vaccines unless a clear benefit could be demonstrated by the few ongoing trials of combination with new immunomodulating reagents (eg, anti-CTLA4, PD-1, chemotherapy).

Novel therapies for metastatic renal cell carcinoma: efforts to expand beyond the VEGF/mTOR signaling paradigm

With six agents approved for metastatic renal cell carcinoma (mRCC) within the past 5 years, there has undoubtedly been progress in treating this disease. However, the goal of cure remains elusive, and the agents nearest approval (i.e., axitinib and tivozanib) abide by the same paradigm as existing drugs (i.e., inhibition of VEGF or mTOR signaling). The current review will focus on investigational agents that diverge from this paradigm. Specifically, novel immunotherapeutic strategies will be discussed, including vaccine therapy, cytotoxic T-lymphocyte antigen 4 (CTLA4) blockade, and programmed death-1 (PD-1) inhibition, as well as novel approaches to angiogenesis inhibition, such as abrogation of Ang/Tie-2 signaling. Pharmacologic strategies to block other potentially relevant signaling pathways, such as fibroblast growth factor receptor or MET inhibition, are also in various stages of development. Although VEGF and mTOR inhibition have dramatically improved outcomes for patients with mRCCs, a surge above the current plateau with these agents will likely require exploring new avenues.

Establishment of a CBRH7919 cell line expressing rat IL-2 and B7-1

AIM: To establish a CBRH7919 cell line CBRH7919 expressing rat IL-2 and B7-1 genes and to examine their ability to express the IL-2 and B7-1 genes in vitro.

METHODS: The IL-2 and B7-1 genes were amplified by RT-PCR and subcloned into retroviral vectors pBaBe-puro and pMSCV-neo, respectively, to obtain the recombinant retroviral vectors pBaBe-puro-IL-2 and pMSCV-neo-B7-1. The recombinant plasmids were then transfected into the 293FT packaging cells. The obtained infectious viruses were used to infect the CBRH7919 cell line, and puro/G418-resistant clones were acquired after puro/G418 selection. The expression of IL-2 and B7-1 was detected using Q-PCR, Western blot and ELISA.

RESULTS: The rat IL-2 and B7-1 genes were successfully amplified by RT-PCR, and the recombinant plasmids pBaBe-puro-IL-2 and pMSCV-neo-B7-1 were successfully constructed and verified by direct sequencing. A CBRH7919 cell line (CBRH7919/IL-2/B7-1) expressing rat IL-2 and B7-1 was established. Q-PCR analysis showed that the expression levels of IL-2 and B7-1 mRNAs in CBRH-7919/IL-2/B7-1 cells were 4.15 and 17.04 times higher than those in CBRH-7919-pmscv-neo cells. Western blot analysis showed that the expression level of B7-1 protein in CBRH-7919/IL-2/B7-1 cells was 3 times more than that in unmodified cells, while ELISA showed that expression level of IL-2 was 190 times more than that in unmodified cells.

CONCLUSION: A CBRH7919 cell line stably and effectively expressing rat IL-2 and B7-1 genes was obtained and provides a good basis for further research of immuno-gene therapy of liver cancer.

Ten years of progress in vaccination against cancer: the need to counteract cancer evasion by dual targeting in future therapies

Although cancer immunology has made vigorous progress over the last decade, its future remains uncertain. Tumors have clearly proved subject to immune surveillance, leading to antigenic editing, and means of activating both T and B arms of the immune system have been devised. Therapeutic vaccination and monoclonal antibody therapy have so far proved disappointing, because tumors prove adept at evasion from immune control. Dual targeting could well counteract evasion, provided that the two targets are independent and are attacked simultaneously. This stage has nearly but not quite been reached in several forms of immunotherapy, particularly of B-cell cancers, although such treatment also carries hazards.

Immunotherapy for renal cell carcinoma

Immunotherapy plays a significant role in the management of renal cell carcinoma (RCC) patients with metastatic disease because RCC is highly resistant to both chemotherapy and radiation therapy. Many reports illustrate various approaches to the treatment of RCC, such as cytokine-, antigen- or dendritic cell- (DC-) based immunotherapy, and the safety and effectiveness of immunotherapy have been highlighted by multiple clinical trials. Although antitumor immune responses and clinically significant outcomes have been achieved in these trials, the response rate is still low, and very few patients show long-term clinical improvement. Recently, the importance of immune regulation by antigen-presenting cells (APC) and regulatory T cells (Treg cells) has also been discussed. The authors outline the principles of cell-mediated tumor immunotherapy and discuss clinical trials of immunotherapy for RCC.

T-cell receptor gene-modified T cells with shared renal cell carcinoma specificity for adoptive T-cell therapy

PURPOSE

Adoptive therapy with genetically engineered T cells carrying redirected antigen specificity is a new option for the treatment of cancer. This approach is not yet available for metastatic renal cell carcinoma (RCC), due to the scarcity of therapeutically useful reagents. We analyzed tumor-infiltrating lymphocytes (TIL) from RCC to identify T-cell specificities with shared tumor-specific recognition to develop T-cell receptor (TCR)-engineered T lymphocytes for adoptive therapy of RCC.

EXPERIMENTAL DESIGN

We established a T-cell clone from TIL that recognized a human leukocyte antigen (HLA)-A2-restricted tumor antigen. The TCR alpha- and beta-chain genes were isolated, modified by codon optimization and murinization, and retrovirally transduced into peripheral blood lymphocytes (PBL). A TCR-expressing indicator line (B3Z-TCR53) was established to screen for antigen prevalence in RCC, other malignancies, and normal cell counterparts.

RESULTS

TCR53-engineered PBL recapitulated the specificity of the TIL and showed tumor-specific HLA-A2-restricted effector activities (IFN-gamma, tumor necrosis factor-alpha, interleukin-2, macrophage inflammatory protein-1beta, cytotoxicity). PBL-TCR53 of healthy donors and RCC patients exhibited similar transduction efficiency, expansion, and polyfunctional profile. Using B3Z-TCR53 cells, 130 tumor and normal cells were screened and shared TCR53 peptide: MHC expression was found in >60% of RCC and 25% of tumor lines of other histology, whereas normal tissue cells were not recognized.

CONCLUSIONS

To date, TCR53 is the only TCR with shared HLA-A2-restricted recognition of RCC. It fulfills the criteria for utilization in TCR gene therapy and advances T cell-based immunotherapy to patients with RCC and other malignancies expressing the TCR ligand.

Systemic therapy of disseminated myeloma in passively immunized mice using measles virus-infected cell carriers

Multiple myeloma (MM) is bone marrow plasma cell malignancy. A clinical trial utilizing intravenous administration of oncolytic measles virus (MV) encoding the human sodium-iodide symporter (MV-NIS) is ongoing in myeloma patients. However, intravenously administered MV-NIS is rapidly neutralized by antiviral antibodies. Because myeloma cell lines retain bone marrow tropism, they may be ideal as carriers for delivery of MV-NIS to myeloma deposits. A disseminated human myeloma (KAS 6/1) model was established. Biodistribution of MM1, a myeloma cell line, was determined after intravenous infusion. MM1 cells were found in the spine, femurs, and mandibles of tumor-bearing mice. Lethally irradiated MM1 cells remained susceptible to measles infection and transferred MV to KAS 6/1 cells in the presence of measles immune sera. Mice-bearing disseminated myeloma and passively immunized with measles immune serum were given MV-NIS or lethally irradiated MV-NIS-infected MM1 carriers. The antitumor activity of MV-NIS was evident only in measles naive mice and not in passively immunized mice. In contrast, survivals of both measles naive and immune mice were extended using MV-NIS-infected MM1 cell carriers. Hence, we demonstrate for the first time that systemically administered cells can serve as MV carriers and prolonged survival of mice with pre-existing antimeasles antibodies.