Advanced renal cell carcinoma treated with granulocyte-macrophage colony-stimulating factor gene therapy: A clinical course of the first Japanese experience

A phase I study of granulocyte-macrophage colony-stimulating factor (GM-CSF) gene-transduced tumor vaccine for patients with metastatic renal cell carcinoma (RCC) was initiated in 1998, as the first cancer gene therapy in Japan. The study is still ongoing, but the first patient is presented here as a case report. The patient was a 60-year-old man with Stage IV CRC with multiple lung metastases. After surgical resection of the tumor, autologous tumor cells were transduced and cultured to produce GM-CSF. The patient received a total of 2.2 x 108 gene-transduced autologous vaccine cells by subcutaneous injection. During the course of vaccination, growth of the largest metastatic mass slowed to some extent; however, multiple new lesions developed. About 1 month after the start of low-dose IL-2 therapy, rapid and remarkable regression in a large lung hilar metastatic mass was noticed. The patient died of progressive disease 7 months after the start of GM-CSF gene therapy. Careful histological examination by autopsy revealed that the responding mass was infiltrated by CD8 positive dominant T lymphocytes, and did not exhibit vasculitis or any other changes associated with active autoimmune disease.     

Durability of complete responses in patients with metastatic cancer treated with high-dose interleukin-2: identification of the antigens mediating response.

OBJECTIVE: To determine the durability of complete responses in patients with metastatic melanoma or renal cancer treated with high-dose bolus interleukin-2 (IL-2) as well as the factors associated with the development of a complete response and the antigens mediating clinical responses. METHODS: A consecutive series of 409 patients with either metastatic melanoma or renal cancer who were treated with high-dose bolus IL-2 in the Surgery Branch, National Cancer Institute, between September 1985 and November 1996 have been analyzed with a median potential follow-up of 7.1 years. All patients were treated with 720,000 IU/kg administered by 15-minute intravenous infusions every 8 hours for up to 5 days as clinically tolerated per cycle. Two cycles constituted a treatment course. Tumor-infiltrating lymphocytes (TIL) from melanoma patients were used to clone the genes encoding the tumor antigens responsible for clinical responsiveness. RESULTS: Thirty-three of 409 (8.1%) patients treated with high-dose bolus IL-2 achieved a complete response and 37 (9%) achieved a partial response. Complete regression was seen in 6.6% and 9.3% of patients with metastatic melanoma and renal cancer, respectively. Twenty-seven of these 33 completely responding patients (82%) remain in ongoing continuous complete response from 39 to more than 148 months from the onset of treatment. Tumor regressions were seen at virtually all organ sites. The absence of prior treatment with immunotherapy, the total dose of IL-2 administered, and the maximal rebound lymphocytosis after cessation of IL-2 correlated with achieving a complete response. Expression cloning techniques have identified a series of tumor antigens that are recognized by TIL grown from resected melanomas. These antigens are mainly melanoma/ melanocyte differentiation antigens, although mutated intracellular proteins can also serve as antigens. CONCLUSIONS: Treatment with high-dose bolus IL-2 mediates complete cancer regression in approximately 8% of patients with metastatic renal cancer and melanoma. The great majority of these patients will enter durable complete regressions and appear to be cured of their metastatic cancer. Thus, immunotherapy with high-dose bolus IL-2 should be considered as initial therapy for appropriately selected patients with metastatic melanoma and renal cell cancer. Identification of the tumor antigens mediating clinical response is opening new therapeutic possibilities for cancer treatment.     

A new approach to the therapy of cancer based on the systemic administration of autologous lymphokine-activated killer cells and recombinant interleukin-2

A new approach to cancer therapy has been developed based on the adoptive transfer of autologous lymphokine-activated killer (LAK) cells and recombinant interleukin-2 (IL-2). Forty-one patients with advanced cancer who have failed all standard treatments were treated in this experimental protocol. Fourteen patients experienced an objective regression of cancer, including one patient with metastatic melanoma who underwent a complete regression. Objective responses were seen in patients with colorectal cancer, renal cell cancer, melanoma, and lung adenocarcinoma. The sites of tumor regression included subcutaneous tissue, lung, and liver. The major side effect of therapy resulted from the administration of high-dose IL-2 and was manifested primarily as fluid retention, resulting in a generalized capillary permeability leak syndrome. This approach to adoptive immunotherapy represents a promising approach to the therapy of patients with metastatic cancer. Attempts to increase the potency and decrease the toxicity of therapy and extend this treatment to patients with smaller tumor burdens are in progress.     

Study on adoptive immunotherapy with tumor-infiltrating lymphocytes (TIL) for renal cell carcinoma--amplification of IL-2-elicited TIL proliferation by OKT3-monoclonal antibody

Human autologous peripheral blood lymphocytes (PBL) and lymphocytes infiltrating renal cell carcinoma (TIL) were cultured with medium containing 1000 IU/ml of human interleukin 2 (IL-2). A high cytotoxic activity against fresh autologous as well as cultured allogenic tumor cells was developed. By culturing these lymphocytes with OKT3 monoclonal antibody during the initial 2 days of long-term culture, in terms of T cell activation signal, IL-2-driven lymphocyte proliferation was remarkably accelerated with maintenance of appreciable level of cytotoxic activity. The same culture method also induced an increase in OKT3 and IL-2 receptor positive lymphocyte population in LAK cells and TIL. This method may enable us to gain more autologous TIL in vitro for adoptive immunotherapy of renal cell carcinoma than the usual culture method with IL-2 alone. Five patients with metastatic renal cell carcinoma were treated with adoptive immunotherapy with TIL, LAK and IL-2. One patient with pulmonary metastasis has had a minor response which has lasted for 3 months so far. We have not experienced any serious side effects during the treatment.     

Vaccinia colon oncolysate immunotherapy for murine hepatic metastases can be modulated with low-dose interleukin-2. Third place winner: Conrad Jobst Award

A murine colon cancer hepatic metastases model was developed via intrasplenic injection of C-C36 tumor cells in syngeneic Balb/c mice to determine the potential efficacy of vaccinia colon oncolysate (VCO) immunoprophylaxis and therapy with and without low-dose interleukin-2 (IL-2) immunomodulation. Mice were injected with 40 micrograms VCO subcutaneously, either prophylactically or therapeutically. IL-2 (Hoffman-La Roche, Nutley, NJ) was administered at a dose of 25,000 units intraperitoneally twice daily for three consecutive days, prophylactically, therapeutically immediately after tumor challenge (early), or 9 days after tumor challenge (late). Mice were followed for 50 days after tumor challenge, and mortalities were recorded. Mice receiving VCO alone did not demonstrate better survival than controls. However, mice receiving VCO with IL-2 immunomodulation demonstrated consistently better survival than mice treated with IL-2 alone or controls. The group receiving VCO therapy with late IL-2 modulation (75% survival demonstrated improved survival over controls (0% survival, P less than 0.00001), VCO-treated mice (0% survival, P less than 0.005), and IL-2-treated mice (29% survival, P = 0.07). In vitro assays revealed enhanced NK activity and suggested cytotoxic T-lymphocyte (CTL) induction as possible mechanisms responsible for these biologic effects. Combined VCO and IL-2 immunotherapy may be of potential benefit to patients with metastatic colon cancer, but further research is required to optimize treatment regimens.     

Melanoma-specific cytotoxic T cells generated from peripheral blood lymphocytes. Implications of a renewable source of precursors for adoptive cellular immunotherapy.

Cytotoxic T lymphocytes (CTL) specific for autologous human melanoma have been generated in vitro from peripheral blood lymphocytes (PBL) of five patients with resectable stage II malignant melanoma. The PBL were cultured with 5u/ml recombinant IL-2 and were repeatedly stimulated with irradiated fresh or cultured autologous tumor cells. Cytotoxicity was determined by four-hour chromium release assays. Specific cytotoxicity developed in 30 to 40 days, after three or four stimulations with tumor. The PBL-derived CTL are CD3+ and are mixed for CD4+ and CD8+ phenotypes. They lysed autologous melanoma and failed to lyse allogeneic melanoma, K562, or autologous lymphocytes. The lysis of autologous tumor was maintained for more than 4 months. The cells proliferated in response to autologous, but not allogeneic melanoma cells, in a dose-dependent manner. Lysis of the autologous tumor target was inhibited with w6/32, a monoclonal antibody to HLA Class I antigens. It is concluded that PBL may serve as a plentiful and renewable source of precursor cells for the generation of autologous tumor-specific CTL, which may be useful in specific adoptive cellular immunotherapy of melanoma.     

The development of gene therapy for the treatment of cancer.

OBJECTIVE: The authors sought to develop new treatments for patients with cancer based on the genetic modification of immune lymphocytes and tumor cells designed to increase the host immune reaction against growing cancers. METHODS: Retroviral-mediated gene transduction was used to introduce genes into tumor-infiltrating lymphocytes (TIL), and these genetically altered TIL were administered to patients with cancer. Genes coding for cytokines were introduced into tumor cells, and these cells were used to immunize patients against their autologous cancers. RESULTS: In initial studies, the gene for neomycin phosphotransferase was introduced into the TIL of ten patients with advanced cancer to study the survival and distribution of TIL in humans. These studies showed that retroviral gene transduction is a safe and practical method for adding genes to human cells and led to clinical trials in which the gene for tumor necrosis factor (TNF) was inserted into TIL in an effort to increase their therapeutic effectiveness. Phase I trials are currently underway using TIL that secrete up to 100 times the normal level of TNF. More recently, animal experiments have revealed that transduction of tumor cells with cytokine genes can enhance tumor immunogenicity and, thus, increase the recognition of the tumor as foreign by the host. Clinical trials based on these observations have begun in which patients are immunized against their own autologous tumors that were transduced with the genes for TNF or interleukin-2. CONCLUSIONS: Attempts at gene therapy for cancer are underway and have opened new possibilities for the development of cancer treatments.     

Regulatory effects of interleukin-4 on tumor-infiltrating lymphocytes derived from human renal cell carcinoma.

We have studied the effects of interleukin-4 (IL-4) on the expansion, proliferation, phenotype, and antitumor activity of tumor-infiltrating lymphocytes (TIL) derived from human renal cell carcinoma. Cultures were obtained from three primary renal tumors and one group of tumor-invaded, regional lymph nodes. IL-4 induced a significant increase in lymphocyte expansion and proliferation, but the response was dependent on the concurrent dose of IL-2 in culture. Increased growth activity was only observed in those cultures receiving low doses (20 U/ml) of IL-2 (average increase of fold expansion of 6.5, P < 0.01) with no changes in growth activity in the high dose (1000 U/ml) cultures. The combination of low dose IL-2 and IL-4 (200 U/ml) promoted lymphocyte growth significantly better than high dose IL-2 alone, the current standard growth regimen for in vitro expansion of TIL. TIL grown in the presence of IL-4 significantly reduced the level of non-specific, non-major histocompatibility complex-restricted antitumor activity (P < 0.01 for allogeneic renal, nonrenal, and NK-sensitive K562 cells), while exhibiting no effect on the level of autologous killing. This is in contrast to previous findings of significant enhancement of autologous antitumor activity using IL-4 on tumor-specific, melanoma-derived TIL. We also evaluated the effects of irradiated autologous tumor stimulation (TIL:tumor ratio, 10:1) on TIL cultures. Addition of autologous tumor cells increased expansion and proliferation of all cultures regardless of concurrent lymphokines present in the culture media (average increase fold expansion of 2.21, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Adoptive immunotherapy and metastasized cancer of the kidney. Regulator effects of interleukin-4 on tumor infiltrating lymphocytes (TIL)]

Adoptive immunotherapy is a new therapeutic approach of the treatment of advanced renal cell cancer. Experimental studies have shown that the cells with the highest cytolytic activity are tumor infiltrating lymphocytes (TIL). The effects of interleukin-4 (IL-4) on the expansion, proliferation, phenotype and antitumor activity of TIL were studied. Cultures were obtained from three primary renal tumors and one group of tumor invaded, regional lymph nodes. IL-4 induced a significant increase in lymphocytes expansion and proliferation, but the response was dependent of the concurrent dose of IL-2 in culture. TIL grown in the presence of IL-4 significantly reduced the level of non specific, non MHC restricted antitumor activity while exhibiting no effect on the level of autologous killing. The effects of irradiated autologous tumor stimulation on TIL cultures were also evaluated. Addition of autologous tumor increased expansion and proliferation of all cultures and significantly enhanced levels of autologous killing. IL-4 and autologous tumor stimulation are effective growth factors when used in combination with a lose dose IL-2 regimen and may be of significant benefit in the expansion of TIL for clinical trials.     

Experience with the use of high-dose interleukin-2 in the treatment of 652 cancer patients.

We have administered 1039 courses of high-dose interleukin-2 (IL-2) to 652 cancer patients. Five hundred ninety-six patients had metastatic cancer that either had failed standard effective therapies or had disease for which no standard effective therapy existed, and 56 patients were treated in the absence of evaluable disease in the adjuvant setting. IL-2 was administered either alone (155 patients) or in conjunction with activated immune cells such as lymphokine activated killer (LAK) cells (214 patients) or tumor infiltrating lymphocytes (TIL) (66 patients), with other cytokines such as alpha interferon (a-IFN)(128 patients) or tumor necrosis factor (TNF)(38 patients), with monoclonal antibodies (32 patients), or with the chemotherapeutic agent cyclophosphamide (19 patients). Initial results with the treatment of high-dose IL-2 alone or in conjunction with LAK cells have indicated that objective regressions of cancer can be achieved in 20% to 35% of patients with selected advanced metastatic cancers. Although most responses have been seen in patients with metastatic renal cell cancer, melanoma, colorectal cancer, and non-Hodgkin's lymphoma, many histologic types of cancer have not been treated in significant numbers. These regressions can be durable; of 18 patients achieving a complete response, ten have not experienced recurrence at intervals from 18 to 52 months. Although combinations of IL-2 with TNF do not appear to result in increased responses, there is a suggestion in our initial phase I studies that the combination of a-IFN and IL-2 is more effective than the administration of cytokine alone and this combination deserves further study. Similarly the adoptive transfer of TIL in conjunction with IL-2 also appears to be more effective than the use of IL-2 alone. The toxic side effects in patients treated with high-dose IL-2 are presented and include malaise, nausea and vomiting, hypotension, fluid retention, and organ dysfunction. Treatment-related deaths were seen in 1% of all treatment courses and in 1.5% of patients. These studies demonstrate that a purely immunologic manipulation can mediate the regression of advanced cancers in selected patients and may provide a base for the development of practical, effective biologic treatments for some cancer patients.     

The effects of interleukin-6 on tumor-infiltrating lymphocytes derived from human renal cell cancer

Tumor-infiltrating lymphocytes (TIL) are a heterogeneous population of T cells with potent antitumor activity against a wide variety of tumors. TIL from renal cell cancer (RCC) typically exhibit diminished growth and antitumor activity after four weeks in vitro. We have therefore investigated effects of varying doses of interleukin-6 (IL-6) (0, 25, 100 units/ml.) on in vitro expansion, proliferation, cytotoxicity, and expression of cell surface phenotypes of long term renal TIL cultures from three RCC patients. Among the various conditions tested, three of three TIL cultures displayed a mild increase in cell expansion when grown in IL-2 with the addition of 100 units/ml. of IL-6. Two of three TIL cultures grown in IL-2 and 100 U/ml. of IL-6 demonstrated enhanced proliferation as determined by 3H-thymidine uptake. TIL could not be isolated or maintained in vitro when grown in the presence of IL-6 alone without IL-2. IL-6 was also found to enhance the long term non-specific cytotoxicity against an allogeneic nonrenal tumor target. No consistent effect on autologous tumor-specific cytotoxicity was demonstrated. We conclude that IL-6, when used in combination with IL-2, may modestly enhance the long-term growth of RCC-derived TIL.     

A novel dendritic cell-based cancer vaccine produces promising results in a syngenic CC-36 murine colon adenocarcinoma model

BACKGROUND: This study was conducted to test the efficacy of a new cancer vaccine, composed of dendritic cells (DCs) pulsed with an interleukin-2 gene-encoded vaccinia virus tumor oncolysate (DC-IL-2VCO) in a CC-36 murine colon adenocarcinoma model. MATERIALS AND METHODS: CC-36 tumor cells were injected subcutaneously into the left flank of four- to six-week old male BALB/c mice. The mice were divided into three groups, each of which received one of the following treatments: (1) DCs pulsed with the IL-2 gene-encoded vaccinia oncolysate (DC-IL-2VCO), (2) DCs pulsed with the tumor oncolysate alone (DC-CO), or (3) no treatment (control). Tumor incidence was measured, and survival rates were compared using a paired Student's t-test. Cytolytic T cell activity was measured in peripheral blood lymphocytes (PBL) and splenic lymphocytes using a (51)Cr-release assay. Lastly, mice were depleted of either CD4+ or CD8+ lymphocytes prior to receiving the vaccine to test the mechanism of tumor immunity in these mice. RESULTS: Mice treated with DC-IL-2VCO demonstrated decreased tumor burden, increased survival, and greater cytolytic activity compared with control mice and mice receiving DC-CO. In addition, mice depleted of CD8+ T cells prior to immunization with IL-2VV + DC-IL-2VCO had a significant increase in the incidence of tumor, similar to the untreated control mice. CONCLUSIONS: DCs pulsed with an IL-2 gene-encoded vaccinia virus tumor oncolysate (DC-IL-2VCO) produced safe and effective immune responses in a murine CC-36 colon adenocarcinoma model. This vaccine (DC-MelVac; Patent no. 11221/5) has the potential to treat humans with cancer, and has received FDA approval for use in Phase I clinical trials.     

Phase i study of intravesical vaccinia virus as a vector for gene therapy of bladder cancer

PURPOSE: Vaccinia virus is a DNA poxvirus previously used as a vaccine to eradicate smallpox. The virus has a high efficiency of infection, replicates in the cytoplasm without chromosomal integration and can transport a large amount of recombinant DNA without losing infectivity. Therefore, it is an excellent choice as a vector for gene delivery in vivo. Large quantities of vaccinia have been injected into dermal, subcutaneous and peripheral lymph node melanoma metastases without significant side effects, and with efficient infection of the tumor cells and recombinant gene transfection. To determine if vaccinia, when given intravesically, can effectively infect bladder mucosa and tumor with acceptable toxicity, we performed a phase I trial of intravesical vaccinia in patients with muscle invasive transitional cell carcinoma before radical cystectomy. MATERIALS AND METHODS: After documenting immune competence and demonstration of a major reaction after revaccination, patients received 3 increasing doses of intravesical Dryvax vaccinia virus (Wyeth-Ayerst Laboratories, Philadelphia, Pennsylvania) that was provided by the Centers for Disease Control. Approximately 24 hours after the third dose, cystectomy was performed and the tissue was examined microscopically. RESULTS: There were 4 patients who were treated. The 3 patients who received the highest doses (100 x 106 plaque forming units) had significant mucosal and submucosal inflammatory infiltration by lymphocytes, eosinophils, and plasma cells into tumor and normal tissue. Dendritic cells were recruited to the site after exposure to the vaccinia. Significant mucosal edema and vascular ectasia were seen. Tumor and normal urothelial cells showed evidence of viral infection, including enlarged vacuolated cells with cytoplasmic inclusions. There were no clinical or laboratory manifestations of vaccinia related toxicity except mild dysuria. Of the 4 patients 3 survived and were free of disease at 4-year followup. CONCLUSIONS: Our study demonstrates that vaccinia virus can be administered safely into the bladder with recruitment of lymphocytes and induction of a brisk local inflammatory response. To our knowledge, this is the first report of direct delivery of live virus into the human bladder. The role of wild type vaccinia as immunotherapy for bladder cancer warrants further study. Furthermore, these data support the exploration of recombinant vaccinia as a putative gene therapy vector for intravesical infection and transfection of bladder tumor cells with cytokine or other genes, an approach that our group pioneered and most recently studied in patients with superficial melanoma.     

Improvement in disease-free survival of melanoma patients in conjunction with serologic response in a phase Ia/Ib Southeastern Cancer Study Group trial of vaccinia melanoma oncolysate

Thirty-nine patients with malignant melanoma who were disease-free after surgery but at high risk for recurrence were treated with vaccinia melanoma oncolysate (VMO) for 12 months. Clinical results, after a mean follow-up of 17 months showed that 25 of 39 patients had no evidence of disease. Comparison of disease-free survival of patients in this study with that of 39 matched controls from other adjuvant trials shows statistically significant advantage of VMO therapy. Evaluation of serological responses of patients undergoing VMO treatment by an enzyme-linked immunosorbant assay (ELISA) showed a positive correlation between IgG antibody binding to cultured melanoma cells and disease-free survival.     

In vitro induction of tumor-specific HLA class I-restricted CD8+ cytotoxic T lymphocytes from patients with locally advanced breast cancer by tumor antigen-pulsed autologous dendritic cells

BACKGROUND: Early dissemination of treatment-resistant tumor cells remains the major cause of metastatic recurrence and death in breast cancer patients. Dendritic cells (DCs) are the most powerful antigen-presenting cells, and recently DC-based vaccination has shown great promise for the treatment of human malignancies by immunological intervention. MATERIALS AND METHODS: CD8+ T lymphocytes derived from peripheral blood mononuclear cells stimulated in vitro with autologous breast tumor antigen-pulsed DCs were tested for their ability to induce a HLA class I restricted cytotoxic T lymphocyte (CTL) response against autologous tumor cells. To correlate cytotoxic activity by CTL with T cell phenotype, two-color flow cytometric analysis of surface markers and intracellular cytokine expression was performed. RESULTS: DC pulsed with breast tumor extracts consistently elicited a tumor-specific HLA class I restricted CTL response in vitro in three consecutive patients harboring locally advanced breast cancer. CTL expressed strong cytolytic activity against autologous tumor cells but did not lyse autologous Epstein Barr virus-transformed lymphoblastoid cell lines and showed variable cytotoxicity against the natural killer-sensitive cell line K-562. In all patients, two color flow cytometric analysis of surface markers and intracellular cytokine expression demonstrated that tumor-specific CTL exhibited an heterogeneous CD8+/CD56+ expression and a striking Th1 cytokine bias (IFNgamma(high)/IL-4 (low)). CONCLUSIONS: Tumor lysate-pulsed DCs can consistently stimulate specific CD8+ CTLs able to kill autologous tumor cells in patients with locally advanced breast cancer in vitro. Tumor antigen-pulsed DC-based vaccinations may be appropriate for the treatment of residual and/or chemotherapy-resistant breast cancer refractory to standard salvage treatment modalities.     

Autologous bone marrow transplantation and melanoma: a focused review of the literature.

Metastatic malignant melanoma has been regarded traditionally as an aggressive cancer highly refractory to standard doses of chemotherapy. Complete responses to standard chemotherapy are less than 5%. To overcome resistance, autologous bone marrow transplantation has been employed in the treatment of this disease. High-dose chemotherapy followed by autologous bone marrow rescue has been associated with increased response rates when compared with standard chemotherapy. A recent survey indicates that at least 283 patients with metastatic melanoma have been treated with this form of therapy thus far. Evaluation of the literature indicates that overall response rates for melanoma patients undergoing autologous bone marrow transplantation range from 46 to 65%, with complete response rates as high as 16%. Although few patients are long-term responders, several patients remain in complete remission for periods of more than one year. Multiple centers are evaluating the utility of high-dose therapy in the high-risk adjuvant setting for patients who present with poor prognosis disease. Data concerning the long-term outcome of this therapy are not available. This article reviews the concepts of high-dose therapy followed by autologous bone marrow transplantation, and the outcomes of patients with malignant melanoma who are treated in this manner.     

Gene and immune therapy for renal cell carcinoma

Conventional therapy for metastatic renal cell carcinoma is associated with a poor response rate and few patients are long-term survivors. The occurrence of spontaneous regression and the prolonged latency period between primary tumor removal and the appearance of metastases in some patients suggest the existence of important host immune responses to autologous tumor cells. With the advent of molecular gene transfer techniques and increased knowledge of the basic pathways of immune activation, the field of cancer immunotherapy has finally begun to develop novel and effective approaches for harnessing the immune system as a therapeutic agent. Current immunotherapy and gene therapy strategies, including methods of cytokine delivery and tumor-cell-based vaccines, are presented.     

B7-1 gene-modified autologous tumor-cell vaccines for renal-cell carcinoma

In recent years, interest in the development of immunologic approaches to malignancies has increased, and there is good evidence that the growth of renal-cell carcinoma (RCC) can be modulated by the host's immune system. Indeed, use of the immunomodulatory cytokine interleukin-2 (IL-2) has been approved for the treatment for this disease. The efficacy of this approach remains low, and there is no other reasonable conventional therapy for patients with metastatic RCC. Therefore, there is a need for the development of novel treatment strategies. The development of autologous tumor-cell vaccines that have been genetically modified to become more immunogenic is an approach that is actively being studied. One of the genetic manipulations that is being employed by several groups is the induction of overexpression of B7-1 to provide costimulation to tumor-reactive T-cells. The rationale for this strategy is that T-cells need two signals before they can mount a cytotoxic response: the binding of the T-cell receptor (TCR) to an antigenic peptide presented on major histocompatibility complex (MHC) molecules and the binding of CD28 to B7-1. Since B7-1 is not normally expressed by RCC cells, the expression forced by transfection of an exogenous B7-1 gene could make the tumor cells more immunogenic. This has been shown to be the case in mice, in which the injection of tumor cells transfected with B7-1 can result in the T-cell-mediated rejection of unmanipulated parental tumor cells. We have applied this approach to the treatment of patients with metastatic RCC. Patients enrolled on our phase I protocol are treated with autologous tumor cells modified to express B7-1, which functions as a tumor vaccine. Primary tumors or metastases are resected from the patients. The tumor cells are adapted to in vitro culture, infected with a recombinant adenoviral vector containing human B7-1 cDNA driven by the cytomegalovirus (CMV) promoter, radiated, and stored in liquid nitrogen. Aliquots of the B7-1 gene-modified tumor cells are given to the patients as a vaccine at varying intervals according to a dose-escalation scheme. The patients also receive systemic IL-2 for the dual purpose of providing accepted therapy for this disease as well as expanding the tumor-reactive T-cells activated by the vaccine. The immunogenicity and toxicity of the vaccine as well as the clinical response are being assessed in three to five patients at each of three dose levels.     

Ex vivo gene therapy using granulocyte-macrophage colony-stimulating factor-transduced tumor vaccines

There is no standard effective therapy for metastatic renal-cell carcinoma (RCC) or prostate cancer. Both of these cancers may be immunogenic, so therapy targeted to a tumor-associated antigen may be effective. Transduction of the gene encoding granulocyte-macrophage colony-stimulating factor has shown promise in preclinical studies, and clinical trials are in their early stages. Both autologous cancer cells and partially HLA-matched allogenic cells are being studied. No dose-limiting side effects have been observed, and a few patients have had transient objective tumor regressions. Further trials with more frequent and, probably, longer immunization schedules are needed to define efficacy.     

Tumor-infiltrating lymphocytes derived from human renal cell carcinoma: Clonal analysis of its characteristics

Aim:   To assess the characteristics of activated tumor-infiltrating lymphocytes (TIL), we report the isolation, growth response, and functional analysis of a CD4^- CD8⁺ TIL-clone derived from human renal cell carcinoma (RCC).
Methods:   Bulk TILs were expanded from a human RCC and the lymphocytes were separated into a CD8⁺ enriched population. Subsequently, using the limiting dilution technique, a TIL clone was established and its growth response, phenotype and cytotoxic activity were analyzed.
Results:   A clone, T16-13, by day 94 numbering 1 × 10⁷ cells, was harvested and characterized as a CD4^- CD8⁺ clone. On day 144, the cytotoxic activity of this clone against the autologous tumor was relatively high (2.3 ± 0.7 LU₃₀/10⁶ cells). Meanwhile, against allogeneic renal tumors, there was no cytotoxic activity (−0.1 LU₃₀/10⁶ cells).
Conclusions:   A TIL clone possessing modest autologous tumor-specific cytotoxicity can be isolated from human RCC. The characteristics analysis of various TIL clones may provide a better understanding of an RCC tumor microenvironment and may help to establish new modalities for the treatment of patients with metastatic kidney cancer.