Clinical and immunologic responses to active specific cancer vaccines in human colorectal cancer.
Topic: Immunotherapy

Colorectal cancer is a common malignant disease, which, despite some progress, still requires improved therapeutic options. Several clinical studies have used active specific immunotherapy (i.e., vaccination) in colorectal cancer. However, the literature still lacks a comprehensive meta-analysis of this approach in advanced colorectal cancer. We did a systematic review with a meta-analysis of clinical studies to evaluate the objective clinical and immunologic response to active specific immunotherapy in patients with colorectal cancer. We conducted a search of Medline and the Web of Science, manually reviewed the literature, and consulted with experts. Criteria for including studies were colorectal cancer patients, active specific immunotherapy to induce a response directed against cancer or cancer antigens, an evaluable tumor burden (i.e., advanced or metastatic colorectal cancer), and precise classification of the patient, disease, and response. Response rates were assessed according to WHO criteria. Primary end points were the objective clinical response rate and the rate of immunologic responses. The secondary end point was the distribution of immune and clinical responses in relation to the route of vaccination and the type of vaccine. Thirty-two phase I/II studies reporting on 527 patients with advanced or metastatic colorectal cancer met all inclusion criteria. Pooled analysis showed an overall response rate (complete response + partial response) of 0.9% for advanced/metastatic colorectal cancer patients who underwent active specific immunization with a broad variety of substances (e.g., autologous tumor cells, peptide vaccine, dendritic cells, idiotypic antibody, and virus-based vaccine). Humoral immune responses were reported in 59%, and cellular ones were reported in 44% of the cases. Mixed or minor responses and disease stabilization are described in 1.9% and 8.3% of colorectal cancer patients, respectively. Pooled results of clinical trials reveal a very weak clinical response rate of <1% for active specific immunization procedures currently available for advanced colorectal cancer. Immune response induction is described in approximately half the patients.

PICO
Population: Patients with advanced or metastatic colorectal cancer
Intervention: Active specific immunotherapy (vaccination) to induce a response directed against cancer or cancer antigens
Comparison: No specific comparison group mentioned in the abstract
Outcomes: Objective clinical response rate, rate of immunologic responses, distribution of immune and clinical responses in relation to the route of vaccination and the type of vaccine

Included studies:
title: Dendritic cell vaccination with MAGE peptide is a novel therapeutic approach for gastrointestinal carcinomas.
abstract: The MAGE gene is selectively expressed in cancer tissues such as melanoma or gastrointestinal carcinomas, whereas no expression is observed in normal tissues except testis. There are several reports of successful induction of HLA class I-restricted antitumor CTLs using MAGE peptides, and some clinical trials with these immunogenic peptides were reported as effective for some patients with malignant melanoma. However, there are no similar studies in gastrointestinal carcinomas, which are important neoplasms. Autologous dendritic cells (DCs) were generated ex vivo and were pulsed with MAGE-3 peptide, depending on the patient's HLA haplotype (HLA-A2 or A24). Patients were immunized with DC pulsed with MAGE-3 peptide every 3 weeks at four times. Twelve patients with advanced gastrointestinal carcinoma (six stomach, three esophagus, and three colon) were treated, and no toxic side effects were observed. Peptide-specific CTL responses after vaccination were observed in four of eight patients. Improvement in performance status was recognized in four patients. Tumor markers decreased in seven patients. In addition, minor tumor regressions evidenced by imaging studies were seen in three patients. These results suggested that DC vaccination with MAGE-3 peptide is a safe and promising approach in the treatment of gastrointestinal carcinomas.
title: Clinical and immune responses in advanced colorectal cancer patients treated with anti-idiotype monoclonal antibody vaccine that mimics the carcinoembryonic antigen.
abstract: Carcinoembryonic antigen (CEA) is expressed in a wide variety of adenocarcinomas, and it is well recognized that cancer patients are immunologically "tolerant" to CEA. The purpose of this study was to determine whether we could break immune tolerance to CEA by vaccinating patients with a monoclonal anti-idiotype antibody that is the internal image of CEA and to determine what impact this might have on patient survival. Twenty-four patients with advanced CEA-positive colorectal cancer who failed standard therapies except for two were entered into this Phase Ib trial. One patient was considered not assessable, because on the day of entering into the study, she was diagnosed with acute myelogenous leukemia. Patients were treated with 1, 2, or 4 mg of aluminum hydroxide-precipitated 3H1 anti-idiotype antibody every other week for four injections and then monthly until tumor progression was observed. Immunological monitoring included humoral and cellular idiotypic and CEA responses, and all patients were evaluated for toxicity, response, and survival. Hyperimmune sera from 17 of 23 patients demonstrated an anti-anti-idiotypic Ab3 response, and 13 of these responses were demonstrated to be true anti-CEA responses (Ab1'). The antibody response was polyclonal, and 11 mediated antibody-dependent cellular cytotoxicity. Ten patients had idiotypic T-cell responses, and five had specific T-cell responses to CEA. None of the patients had objective clinical responses, but overall median survival for the 23 evaluable patients was 11.3 months, with 44% 1-year survival (95% confidence interval, 23-64%). Toxicity was limited to local swelling and minimal pain. Anti-idiotype monoclonal antibody 3H1 that mimics CEA was able to break immune tolerance in the majority of treated patients. Overall survival of 11.3 months was comparable to other phase II data with advanced colorectal cancer patients treated with a variety of chemotherapy agents, including irinotecan, with considerably less toxicity. Although it is not clear that the vaccine itself had an impact on survival, this should be determined in a Phase III randomized trial.
title: Altered peptide ligand vaccination with Flt3 ligand expanded dendritic cells for tumor immunotherapy.
abstract: Most tumor-associated antigens represent self-proteins and as a result are poorly immunogenic due to immune tolerance. Here we show that tolerance to carcinoembryonic antigen (CEA), which is overexpressed by the majority of lethal malignancies, can be reversed by immunization with a CEA-derived peptide. This peptide was altered to make it a more potent T cell antigen and loaded onto dendritic cells (DCs) for delivery as a cellular vaccine. Although DCs are rare in the blood, we found that treatment of advanced cancer patients with Flt3 ligand, a hematopoietic growth factor, expanded DCs 20-fold in vivo. Immunization with these antigen-loaded DCs induced CD8 cytotoxic T lymphocytes that recognized tumor cells expressing endogenous CEA. Staining with peptide-MHC tetramers demonstrated the expansion of CD8 T cells that recognize both the native and altered epitopes and possess an effector cytotoxic T lymphocyte phenotype (CD45RA(+)CD27(-)CCR7(-)). After vaccination, two of 12 patients experienced dramatic tumor regression, one patient had a mixed response, and two had stable disease. Clinical response correlated with the expansion of CD8 tetramer(+) T cells, confirming the role of CD8 T cells in this treatment strategy.
title: Safety and immunogenicity of a DNA vaccine encoding carcinoembryonic antigen and hepatitis B surface antigen in colorectal carcinoma patients.
abstract: Despite an abundance of preclinical data, relatively little is known regarding the efficacy of DNA vaccination in humans. Here, we present results from a dose-escalation clinical trial of a dual expression plasmid encoding carcinoembryonic antigen (CEA) and hepatitis B surface antigen (HBsAg) in 17 patients with metastatic colorectal carcinoma. CEA was selected as a prototypic tumor-associated self-antigen, and the HBsAg cDNA was included as a positive control for immune response to the DNA vaccine without relying upon breaking tolerance to a self-antigen. Groups of 3 patients received escalating single i.m. doses of the DNA vaccine at 0.1, 0.3, and 1.0 mg. Subsequent groups of 3 patients received three repetitive 0.3- or 1.0-mg doses at 3-week intervals. A final group of 2 patients received three repetitive 2.0 mg doses at 3-week intervals. Toxicity was limited to transient grade 1 injection site tenderness, fatigue, and creatine kinase elevations, each affecting a minority of patients in a non-dose-related manner. Repetitive dosing of the DNA vaccine induced HBsAg antibodies in 6 of 8 patients, with protective antibody levels achieved in four of these patients. CEA-specific antibody responses were not observed, but 4 of 17 patients developed lymphoproliferative responses to CEA after vaccination. No objective clinical responses to the DNA vaccine were observed among this population of patients with widely metastatic colorectal carcinoma. Nevertheless, this pilot trial has provided encouraging human immune response data in support of this vaccine technology.
title: Cancer regression and autoimmunity in patients after clonal repopulation with antitumor lymphocytes.
abstract: We report here the adoptive transfer, to patients with metastatic melanoma, of highly selected tumor-reactive T cells directed against overexpressed self-derived differentiation antigens after a nonmyeloablative conditioning regimen. This approach resulted in the persistent clonal repopulation of T cells in those cancer patients, with the transferred cells proliferating in vivo, displaying functional activity, and trafficking to tumor sites. This led to regression of the patients' metastatic melanoma as well as to the onset of autoimmune melanocyte destruction. This approach presents new possibilities for the treatment of patients with cancer as well as patients with human immunodeficiency virus-related acquired immunodeficiency syndrome and other infectious diseases.
title: Active specific immunotherapy for stage II and stage III human colon cancer: a randomised trial.
abstract: Colon cancer is curable by surgery, but cure rate depends on the extent of disease. We investigated whether adjuvant active specific immunotherapy (ASI) with an autologous tumour cell-BCG vaccine with surgical resection was more beneficial than resection alone in stage II and III colon cancer.
title: Interleukin 2 gene therapy of colorectal carcinoma with autologous irradiated tumor cells and genetically engineered fibroblasts: a Phase I study.
abstract: The purpose of this study was to determine the safety, toxicity, and antitumor immune response following S.C. immunizations with a mixture of irradiated, autologous tumor cells and autologous fibroblasts that were genetically modified to express the gene for interleukin 2 (IL-2) in patients with colorectal carcinoma. Ten patients were treated with a fixed dose of tumor cells (10(7)) and escalating doses of fibroblasts secreting IL-2 (per 24 h): 100 units (three patients), 200 units (three patients), 400 units (three patients), and 800 units (one patient). Pre- and posttreatment peripheral blood mononuclear cells were evaluated for evidence of antitumor immune responses. Fatigue and/or flu-like symptoms were experienced by seven patients and delayed-type hypersensitivity-like skin reactions were observed at the sites of the second or subsequent vaccinations in five patients. Low frequencies of tumor cytotoxic T-cell precursors (range, 1/190,000-1/1,320,000 peripheral blood mononuclear cells) were detected prior to therapy in four of seven patients. There was a 5-fold increase following treatment in the frequency of tumor cytotoxic T-cell precursors in two of six evaluable patients. Some patients with colorectal cancer have low frequencies of tumor cytotoxic T-cell precursors that may be increased by this well-tolerated form of IL-2 gene therapy, which warrants continued clinical evaluation.
title: Generation of carcinoembryonic antigen (CEA)-specific T-cell responses in HLA-A*0201 and HLA-A*2402 late-stage colorectal cancer patients after vaccination with dendritic cells loaded with CEA peptides.
abstract: We intranodally immunized metastatic colorectal carcinoma patients, who had failed standard chemotherapy, with dendritic cells (DCs) pulsed with HLA-A*0201- or HLA-A*2402-restricted carcinoembryonic antigen (CEA) peptides to evaluate the safety of this treatment and the immune response against CEA peptides before and after the treatment.
title: [Vegetating basalioma].
abstract: A huge nodular and ulcerous basal cell carcinoma in a 78-year-old male patient slowly developed over a period of 10 years. Although the tumor had existed such a long time, there was no indication for destructive deep growth or formation of metastases.
title: Results of a phase I trial of a recombinant vaccinia virus that expresses carcinoembryonic antigen in patients with advanced colorectal cancer.
abstract: The inadequacy of systemic treatments of advanced colorectal cancer has aroused interest in biologic therapy. Recent animal models have demonstrated the efficacy and safety of a recombinant vaccine that contains vaccinia and the gene for carcinoembryonic antigen (rV-CEA).
title: Clinical responses with active specific intralymphatic immunotherapy for cancer--a phase I-II trial.
abstract: We evaluated the method of active specific intralymphatic immunization to treat cancer in 32 patients with various tumor types as part of a broad-based phase I-II evaluation and describe the results of 3 sequential series. In series 1, the patients (n = 13) received 2 or more injections of autologous, cryopreserved, irradiated tumor cells directly into the lymphatic system through the cannulation of a dorsal pedal lymphatic channel. In series 2, the patients (n = 7) received low-dose cyclophosphamide, 300 mg per m2, 3 days before the autologous cell vaccine was administered. Series 3 (12 patients) was similar to series 2 except that the tumor cells were treated with cholesteryl hemisuccinate immediately before irradiation. Patients received from 2 to 6 injections of cells, depending on availability, at 2-week intervals. In all, 91 treatments are evaluated in this study. Clinical responses occurred in 7 of the 32 patients and were seen in all 3 series with about the same frequency. These responses occurred in cases of melanoma, lung cancer, colon cancer, and sarcoma. Regressions occurred in both visceral and subcutaneous sites. There was little toxicity, the chief side effect being local discomfort or inflammation. This experience indicates that active specific intralymphatic immunotherapy is safe, produces antitumor effects, and requires more investigation to increase the frequency and duration of observable tumor regression.
title: Phase I study in advanced cancer patients of a diversified prime-and-boost vaccination protocol using recombinant vaccinia virus and recombinant nonreplicating avipox virus to elicit anti-carcinoembryonic antigen immune responses.
abstract: This trial sought to determine, for the first time, the validity in human vaccinations of using two different recombinant vaccines in diversified prime-and-boost regimens to enhance T-cell responses to a tumor antigen.
title: Clinical outcome of colorectal cancer patients treated with human monoclonal anti-idiotypic antibody.
abstract: A human monoclonal anti-idiotypic antibody (105AD7) has been developed which mimics a colorectal-tumour-associated antigen and induces cellular anti-colorectal tumour immune responses in animals. Thirteen patients with advanced colorectal cancer were immunized with 105AD7 and their survival was compared with that of a contemporary group of unimmunized patients with similar disease status. No toxicity related to anti-idiotype immunization was seen. Cellular responses to anti-idiotypic immunization were indicated by lymphocyte proliferation to gp72-positive tumour cells, and production of interleukin-2; anti-tumour antibodies were not detected. Median survival following diagnosis of advanced disease of immunized patients was 12 months, compared with 4 months in unimmunized patients. The improved survival of immunized patients in this study without associated toxicity suggests that 105AD7 immunization may have considerable potential for immunotherapy of colorectal cancer.
title: Adjuvant active specific immunotherapy for stage II and III colon cancer with an autologous tumor cell vaccine: Eastern Cooperative Oncology Group Study E5283.
abstract: A randomized phase III clinical trial of adjuvant active specific immunotherapy (ASI) with an autologous tumor cell-bacillus Calmette-Guérin (BCG) vaccine was conducted to determine whether surgical resection plus ASI was more beneficial than resection alone in stage II and III colon cancer patients.
title: Development of tumor B-cell lymphocyte hybridoma (TBH) autovaccination. Results of a phase I-II clinical trial.
abstract: To improve patient immune recognition of autologous tumor cells, we have developed a tumor B-cell lymphocyte hybridoma (TBH) autovaccination protocol. This approach is based on immunization of a cancer patient with a hybridoma cell suspension derived from the fusion of autologous activated B-cells and autologous cancer cells. This hybrid allows the host immune system to recognize and destroy oncocytes with low toxicity and high specificity. Of 21 treated patients with very advanced diseases, six complete responses and four partial responses were achieved. Overall, survival was prolonged. Side-effects and combination therapies with IL2, IL6 and gamma I/FN are discussed in this paper. Breast and colon cancer seem to be sensitive to this therapy.
title: Phase I study of sequential vaccinations with fowlpox-CEA(6D)-TRICOM alone and sequentially with vaccinia-CEA(6D)-TRICOM, with and without granulocyte-macrophage colony-stimulating factor, in patients with carcinoembryonic antigen-expressing carcinomas.
abstract: Our previous clinical experience with vaccinia and replication-defective avipox recombinant carcinoembryonic antigen (CEA) vaccines has demonstrated safety and clinical activity with a correlation between CEA-specific immune response and survival. Preclinical evidence demonstrated that the addition of the transgenes for three T-cell costimulatory molecules (B7-1, ICAM-1, LFA-3, designated TRICOM) results in a significant improvement in antigen-specific T-cell responses and antitumor activity. We describe here the first trial in humans of the CEA-TRICOM vaccines (also including an enhancer agonist epitope within the CEA gene).
title: Pilot study of a dual gene recombinant avipox vaccine containing both carcinoembryonic antigen (CEA) and B7.1 transgenes in patients with recurrent CEA-expressing adenocarcinomas.
abstract: Coordinated presentation of antigen and costimulatory molecules has been shown to result in the induction of an antigen-specific T-cell response rather than the development of anergy. This study evaluated the vaccine ALVAC-CEA B7.1, a canary pox virus that has been engineered to encode the gene for the tumor-associated antigen carcinoembryonic antigen (CEA) and B7.1, a T-cell costimulatory molecule. Patients with CEA-expressing tumors were immunized with 2.5 x 10(7) (n = 3), 1.0 x 10(8) (n = 6), and 4.5 x 10(8) (n = 30) plaque-forming units intradermally every other week for 8 weeks. Patients with stable or responding disease received monthly boost injections. Biopsies of vaccine sites were obtained 48 h after vaccination to evaluate leukocytic infiltration and CEA expression. Induction of CEA-specific T-cell precursors was assessed by an ELISPOT assay looking for the production of IFN-gamma. Therapy was well tolerated, without significant toxicity attributable to vaccine. All patients had evidence of leukocytic infiltration and CEA expression in vaccine biopsy sites. Six patients with elevated serum CEA values at baseline had declines in their levels lasting 4-12 weeks. These patients all had stable disease after four vaccinations. After four vaccinations, patients who were HLA-A-2-positive demonstrated increases in their CEA-specific T-cell precursor frequencies to a CEA-A2-binding peptide from baseline. The number of prior chemotherapy regimens was inversely correlated with the ability to generate a T-cell response. ALVAC-CEA B7.1 is safe in patients with advanced, recurrent adenocarcinomas that express CEA, and it is associated with the induction of a CEA-specific T-cell response.
title: Immunotherapy with autologous, human dendritic cells transfected with carcinoembryonic antigen mRNA.
abstract: Immunizations with dendritic cells (DC) transfected with RNA encoding tumor antigens induce potent tumor antigen-specific immune responses in vitro and in murine models. We performed a phase I study of patients with advanced carcinoembryonic antigen (CEA)-expressing malignancies followed by a phase II study of patients with resected hepatic metastases of colon cancer to assess safety and feasibility of administering autologous DC loaded with CEA mRNA. The immunizations were well tolerated. Of the 24 evaluable patients in the dose-escalation phase, there was 1 complete response (by tumor marker), 2 minor responses, 3 with stable disease, and 18 with progressive disease. In the phase II study, 9 of 13 patients have relapsed at a median of 122 days. Evidence of an immunologic response was demonstrated in biopsies of DC injection sites and peripheral blood of selected patients. We conclude that it is feasible and safe to administer mRNA-loaded DC to patients with advanced malignancies.
title: Phase I study of immunization with dendritic cells modified with fowlpox encoding carcinoembryonic antigen and costimulatory molecules.
abstract: To determine the safety and immunologic and clinical efficacy of a dendritic cell vaccine modified to hyperexpress costimulatory molecules and tumor antigen.
title: A phase I trial of a synthetic mucin peptide vaccine. Induction of specific immune reactivity in patients with adenocarcinoma.
abstract: We tested a 105 amino acid synthetic mucin MUC-1 peptide that has 5 repeated immunodominant epitopes to evaluate toxicity and detect mucin-specific immune responses in patients with adenocarcinoma. We also studied the enhancement of these responses by vaccinating patients with the synthetic mucin peptide admixed with BCG. Mucins are glycoproteins present on the luminal surface of ductal epithelial cells and on tumors derived from them. The MUC-1 mucin is hypoglycosylated and nonpolarized on tumors and this exposes epitopes that can stimulate cytotoxic T-Cells (CTL). We vaccinated 63 patients with 100 micrograms of the 105aa mucin peptide mixed with BCG. Two additional vaccinations were given at 3-week intervals. All patients were able to tolerate vaccination, with most experiencing local ulceration at the vaccination site. All patients underwent hypersensitivity (DTH) testing with the 105aa and shorter mucin peptides, prior to vaccination. DTH responses were evaluated at 48 hr and the sites of highest peptide concentration were biopsied. Only 3 patients had a strong skin response to the long peptide. Examination of 55 biopsies showed intense T-Cell infiltration in 37 patients and lesser infiltration in 7. Seven of 22 patients tested had a 2- to 4-fold increase in mucin-specific CTLp. Serum levels of IL-6 were measured sequentially using the B9 hybridoma bioassay. Increasing serum levels of IL-6 correlated with constitutional symptoms (significance 0.001) and hypoalbuminemia (significance 0.007) but not with the extent of skin breakdown at vaccination sites. We conclude that mucin vaccination is safe and might serve to enhance specific responses to tumor antigens. IL-6 may be responsible for the constitution symptoms and hypoalbuminemia in these patients.
title: Immunization of colorectal cancer patients with recombinant baculovirus-derived KSA (Ep-CAM) formulated with monophosphoryl lipid A in liposomal emulsion, with and without granulocyte-macrophage colony-stimulating factor.
abstract: KSA (Ep-CAM) is highly expressed by colorectal cancers. The safety and immunologic effects of a vaccine consisting of recombinant baculovirus-derived KSA formulated with monophosphoryl lipid A (MPL) in liposomes and emulsified in mineral oil were evaluated, with and without co-administration of granulocyte-macrophage colony-stimulating factor (GM-CSF). Eleven patients with metastatic colorectal cancer received three subcutaneous (s.c.) injections of the vaccine at 4-week intervals. Six patients were randomized to also receive human recombinant GM-CSF (rGM-CSF) by subcutaneous injection daily for 4 days with each vaccination. Immunizations with and without rGM-CSF were well tolerated. Seven of the 11 patients developed significant KSA-specific cellular immune responses as assessed by lymphoproliferation and interferon-gamma (IFN-gamma) ELISPOT assays. All nine tested patients developed positive delayed type hypersensitivity reactions. Eight of the 11 patients developed KSA-specific antibody responses. The highest levels of cellular immune responses were observed in patients who received GM-CSF. Immunization with baculovirus-derived KSA formulated with monophosphoryl lipid A in liposomal emulsion is safe and can elicit KSA-specific immune responses. Co-administration of GM-CSF with this formulation is an effective method of generating KSA-specific T-helper (Th) 1-associated cellular immune responses.