Active Specific Immunotherapy Research Articles

Immunotherapy: new options in breast cancer treatment

Immunotherapy is a promising new approach in breast cancer treatment, complementing surgery, chemotherapy, radiation and antihormonal therapy. Primarily, two treatment options are available which are supported by a rapidly growing body of clinical evidence. These are active specific immunotherapy with Theratope® and passive immunotherapy targeting the HER-2 receptor with trastuzumab (Herceptin®). Trastuzumab has a proven efficacy as monotherapy as well as in combination with chemotherapeutic agents in HER-2-overexpressing metastatic breast cancer. Trastuzumab is generally well tolerated although cardiotoxicity has been observed, especially when in combination with doxorubicin (Adriamycin®), where this can be a serious concern. Therefore, less cardiotoxic combinations with docetaxel (Taxotere®), vinorelbine (Navelbine®) and epirubicin (Pharmorubicin®) or cyclophosphamide (Endoxana®) have been tested. The combination of trastuzumab with paclitaxel (Taxol®) is well approved. The use of trastuzumab in adjuvant and preoperative therapy is currently being examined in controlled trials. After a brief outline of immunotherapy with Theratope and trastuzumab, this article reviews recent and ongoing clinical studies conducted with trastuzumab.

In this issue

Suppression of the immune system is a problem faced by many cancer patients, especially those whose diseases are in an advanced stage. Elucidating the mechanism(s) behind this immunosuppression would be beneficial in trying to counter it and bolster immune response to tumors. To this end, Takahashi et al. are studying the effects of macrophages in tumor-draining lymph nodes (MTDL) on T-cell apoptosis and comparing these effects among patients with early and advanced stage gastric cancer. In their paper on pages 393–399 they report two interesting findings. Firstly, they note that, in patients with advanced stage gastric cancer, MTDL induce T-cell apoptosis, elevate caspase-3 activity in peripheral T-cells, reduce expression of signal transducing TCR ζ molecules and impair production of IFN ζ. Secondly, they note that MTDL from patients with advanced stage gastric cancer are qualitatively different from those with an early stage of the disease: they exhibit an increased production of hydrogen peroxide and elevated production of intracellular IL-10 and IL-12. Hydrogen peroxide had been known to induce T-cell apoptosis; however, the presence of catalase, a selective scavenger of hydrogen peroxide, did not prevent MTDL downregulation of TCR ζ. This then must occur by another mechanism. Even so, this paper supports the notion that normalization of T-cell function by anti-oxidant therapy is an advantageous course of study. Carcinoembryonic antigen (CEA) is a 180- to 200-kDa glycoprotein, expressed by various types of neoplasms, that is widely used as a human tumor marker. Clinical trials have investigated the possibility that CEA may be used as a target antigen for active specific immunotherapy of patients with colorectal carcinoma. Unfortunately, the use of CEA-directed vaccines has thus far been unsuccessful in controlling cancer progression in humans. One hypothesis for this failure is that CEA is expressed heterogeneously in the tumor. Thus, pharmacological or biological agents that may increase the expression of CEA and MHC molecules have been sought. The anti-metabolite 5-fluorouracil (5-FU) has been shown to upregulate CEA and MHC expression in various colon and breast carcinoma cell lines in vitro, although the mechanism(s) responsible for this upregulation remain unknown. In their report on pages 437–445 of this issue, Correale et al. extend the ramifications of these findings by demonstrating that 5-FU treatment enhances cancer cell susceptibility to the lytic effects of CEA peptide-specific cytotoxic T-cells. Kaplan-Meier plotting of overall (p = 0.0012) and disease-free (p = 0.0033) survival of SMAD7 deletion. Boulay et al. studied the influence of each of these genes on the clinical outcome of patients suffering from colorectal cancer, and their results are published on pages 446–449. They had previously defined SMAD4 deletion as a negative predictive marker for a benefit of chemotherapy. They observed no clinical relevance for SMAD2 deletion, but SMAD7 deletion had a low hazard ratio for both relapse and death, while its amplification had a hazardous effect on survival. Given that SMAD7 is the only SMAD specifically inhibitory for TGFβ, these data suggest that SMAD7 deletion may enhance sensitivity to the tumor suppressor activity of TGFβ and confirm the hypothesis that resistance to TGFβ-mediated apoptosis is an important factor in the expansion of colorectal carcinoma. Effect of ATN-161, with or without 5-FU, on vessel counts, tumor cell proliferation and tumor cell apoptosis. On pages 496–503 of this issue, Stoeltzing et al. hypothesize that the blocking of α5β1 binding to fibronectin by a different peptide antagonist, ATN-161, which does not affect cell adhesion, may show the same results. Furthermore, they suggest that α5β1 need not be expressed on the cancer cells to achieve these results, as the more sensitive target is the α5β1 on the activated endothelial cells. They also thought that chemotherapy with the anti-metabolite 5-fluorouracil (5-FU) might synergize with the anti-angiogenic effects of the peptide to inhibit angiogenesis and the growth of liver metastases in a murine model. As their report demonstrates, they were correct in all of their hypotheses; not only did the combination therapy increase tumor cell apoptosis, decrease tumor cell survival and reduce the formation of liver metastases, it improved survival in a murine colon cancer model.

Rationale for the Clinical Development of STn-KLH (Theratope®) and Anti—MUC-1 Vaccines in Breast Cancer

Mucin-1 (MUC-1) is a high-molecular-weight glycoprotein rich in serine and threonine residues that are Oglycosylated. Expression of MUC-1 is increased in breast, ovarian, and other adenocarcinomas, and altered glycosylation results in exposure of novel peptide epitopes and the expression of tumor-associated carbohydrate residues, such as Thomsen-Freidenreich and sialyl-Tn (STn) antigens. Preclinical studies suggested that induction of immune response to tumor-associated carbohydrate moieties results in inhibition of tumor growth. A synthetic STn—keyhole limpet hemocyanin (KLH) vaccine (Theratope®) is currently being evaluated in clinical trials as active specific immunotherapy in the treatment of advanced breast cancer. Two phase II trials in 50 breast cancer patients compared the STn-KLH vaccine with and without a single low-dose infusion of cyclophosphamide used as an immunomodulator prior to initiation of treatment. Humoral immune responses were higher in patients who had received low-dose cyclophosphamide intravenously (I.V.) compared with patients who had received no cyclophosphamide or oral cyclophosphamide. There was a statistically significant survival difference between all patients treated with the STn-KLH vaccine (overall median survival, 19.1 months; n = 50) and the retrospective control patients (overall median survival, 9.2 months; n = 104). Furthermore, patients who received cyclophosphamide I.V. prior to the STn-KLH vaccine had median survival rates close to 3 times that of patients in a retrospective, frequency-matched, control group who received conventional therapies (cyclophosphamide-I.V. group, 26.5 months vs. 9.2 months, control group). The trials reported a minimal toxicity profile with local reactions in the injection site and some flu-like symptoms. On the basis of the phase II trial results, other supporting data phase III clinical trial of the STn-KLH vaccine is underway. The trial was closed to enrollment in March 2001 with the accrual of 1030 women. The final analysis is event driven and is expected to commence mid 2003.

Clinical Development of the STn-KLH Vaccine (Theratope®)

The development of active specific immunotherapy depends on the identification of altered cancer cell—specific molecules or epitopes that are immunogenic. Many cancer-specific peptide or glycoprotein target antigens have been identified. Tumors carrying aberrant epitopes as a result of underglycosylation of mucins are associated with poor prognosis in many epithelial cancers. The aberrant mucin sialyl-Tn (STn) epitope, in addition to being a predictor of poor prognosis when expressed in tumors, is associated with increased aggressiveness and metastatic potential, making it a promising target for immunotherapy. The STn—keyhole limpet hemocyanin (KLH) vaccine (Theratope®) is an investigational active specific immunotherapy consisting of a synthetic STn epitope conjugated to a high molecular weight protein carrier, KLH. The immune response generated by the STn-KLH vaccine is both humoral and cellular. More than 1000 breast cancer patients with metastatic disease are currently enrolled in a phase III clinical trial to assess the safety and efficacy of the STn-KLH vaccine. Interim analysis from a current phase III trial has confirmed the safety of the STn-KLH vaccine, and the clinical outcome awaits the final analysis expected in 2003.

Intradermal injection of Newcastle disease virus‐modified autologous melanoma cell lysate and interleukin‐2 for adjuvant treatment of melanoma patients with resectable stage III disease

The value of active specific immunotherapy (ASI) for the treatment of solid tumours still has to be assessed. The objective was to test an autologous tumour cell vaccine for adjuvant treatment of stage III melanoma patients. After open vaccination of 12 patients, another 17 patients were recruited for a randomized double-blind trial comparing treatment with the vaccine (n = 9) and with a placebo (n = 8). Intracutaneous vaccinations were given postoperatively in weeks 2, 4, 6, 12, 24 and thereafter every 6 months if sufficient vaccine material was available. Patients were followed for 60-84 months. Median disease-free survival time was 5 months for open-treated, 4 months for verum-treated and 6 months for placebo-treated patients. Corresponding median overall survival times were 30.5, 18 and 18.5 months, respectively. There were no remarkable differences between the verum and the placebo group. Adjuvant treatment of melanoma patients with an autologous ASI vaccine did not show clinical efficacy in this cohort of melanoma patients.

Immunotherapy as part of combinations for the treatment of cancer

Immunotherapy (biological therapy) comprises such things as active specific immunotherapy (“cancer vaccines”), nonspecific immunostimulation with cytokines, and the inhibition of suppressor influences exerted or elicited by the tumor. Just as cancer chemotherapy began with the use of single agents and evolved into combination therapy, so immunotherapeutic agents have been combined with each other and with chemotherapy. The alkylating agent cyclophosphamide (Cytoxan; CY) has been used for many years to inhibit tumor-derived suppressor influences in rodents, and has been exploited for the same use in humans. Combinations of CY and cancer vaccines such as autologous tumor cells, Melacine, large multivalent immunogen (LMI), and Theratope have been tested with some success in humans for more than a decade. In this use, the CY is a biological response modifier rather than an antitumor agent. Delayed treatment with CY in treating mouse plasmacytomas has proved more effective than immediate treatment, probably because it allows immunity to develop in the host. CY and moderate-dose interleukin-2 (IL-2) have also been a useful regimen in treating human melanomas. IL-2 is itself a useful component of combination immunotherapy, such as with melanoma peptide vaccines, or with interferon-alfa-2b, (IFN-a), as a dual combination or part of a biochemotherapy regimen. IL-2 and histamine, to block reactive oxygen species, may be a more useful combination for treatment of liver metastases of melanoma than IL-2 alone. In this combination, the histamine may permit continued, unimpeded activity of cytolytic T lymphocytes. Several different combinations of drugs and biological agents have been used as biochemotherapy for melanoma, but although there are higher immediate response rates, the long-range survival benefits have been marginal, not justifying the severe toxicity. Combinations of 5-fluorouracil (5-FU) and IFN-a or levamisole have had efficacy in colon and head and neck cancers, but here the biological agents acted as biochemical modulators. Trials of antibodies and chemotherapy have been limited. It appears that trastuzumab (Herceptin) potentiates antitumor therapy in breast cancer and also increases the cardiotoxicity of those regimens.

Tissue Microarray Evaluation of Melanoma Antigen E (MAGE) Tumor-Associated Antigen Expression

Objective To evaluate MAGE tumor-associated antigen (TAA) expression in an extensive panel of normal and neoplastic tissues. Summary Background Data TAAs of the MAGE family represent targets of active specific immunotherapy. Limited-size studies indicate that they are expressed in normal testis and tumors of different histologies. High-throughput tissue microarray (TMA) technology and MAGE TAA-specific monoclonal antibodies now allow us to comprehensively evaluate their expression in large numbers of tissues and to address clinical correlations. Methods A TMA containing 3,520 samples from 197 different tissues and a non-small-cell lung cancer TMA including 301 specimens were stained using the MAGE TAA-specific monoclonal antibody 57B. For patients with squamous cell carcinoma of the lung, the dichotomous result (positive vs. negative) of MAGE TAA staining was used as a predictor variable along with other covariates in proportional hazard regression analysis of tumor-specific survival. Results MAGE TAAs are expressed with frequencies ranging between 22.7% (larynx) and 50% of cases (lung) in squamous cell carcinomas from different anatomic areas and in large cell carcinomas of the lung (37.9%). The authors provide here the first description of MAGE TAA expression in basalioma (48.1%). To investigate the clinical significance of MAGE expression in a frequently positive tumor type, a non-small-cell lung cancer, TMA was then studied. In this TMA 43.2% of tumors were 57B positive. In patients with squamous cell carcinoma, MAGE TAA positivity was significantly correlated with a shorter tumor-specific survival in the proportional hazard regression analysis model. Conclusions These data suggest novel potential therapeutic indications in different types of cancers. In lung squamous cell carcinoma, the significant association of MAGE TAA expression with poor prognosis suggests that patients with 57B-positive tumors may benefit from early, specific immunotherapy procedures.

Studies using the anti-idiotypic monoclonal antibody 105AD7 in patients with primary and advanced colorectal cancer.

The mortality from colorectal cancer has not changed appreciably in the last 30 years and new treatment avenues, such as immunotherapy, are being explored. 105AD7 is a form of active specific immunotherapy that aims to stimulate specific T-cells to target tumour specific antigens on colorectal cancer cells. Results indicate that the cancer vaccine 105AD7 is non-toxic and is capable of stimulating T-cells to target tumour specific antigens, become activated, and kill tumour cells by apoptosis. These immune responses have no effect on survival on a cohort of immunosuppressed patients with advanced disease, but results from a case-control study in patients with minimal residual disease suggest they may confer a slight survival advantage on patients receiving 105AD7.

Experimental study of active specific immunotherapy for cervic cancer with tumor vaccine

Objectives To evaluate the active immunotherapeutic efficacy of tumor vaccine with new adjuvants. Methods HeLa cells, rIL\|2,rGM\|CSF,traditional Chinese medicine and Feud's adjuvant were mixed together to form tumor vaccine. An animal model of tumor vaccination was established. The 51 C r release assay was used to examine the cytotoxicities of three kinds of the splenocytes to cervic cancer cells. Serum IL\|10, IFN\|γ were tested. The other mice in every group were fed continously to calculate survival time. Results Specific cytocidal rate of splenocytes from the immunized mice to cervic cancer cell was 39% when E:T was 200:1,which was significantly higher than that from the other two groups. Serum IFN\|γ in immunized group was increased obviously compared with other groups( P 0.01). The survival time of the mice in immunized group were prolonged. Conclusions The novel tumor vaccine can improve the host's antitumor immune response.

Active immunotherapy by reinduction with a polyvalent allogeneic cell vaccine correlates with improved survival in recurrent metastatic melanoma

We have observed prolonged survival in patients undergoing vaccine reinduction after resection of recurrent metastatic melanoma and adjuvant polyvalent allogenic cell vaccine (PACV) immunotherapy. We hypothesized that reinduction with a more intensive vaccine regimen would re-stimulate specific immune responses that were correlated with survival after recurrence. From 1996 to 1998, 194 patients developed recurrence during adjuvant PACV (CancerVax vaccine) treatment after resection of metastatic melanoma. Recurrent disease was treated with or without vaccine reinduction. Reinduction regimen entailed an increased vaccine frequency and coadministration of two doses of bacille Calmette-Guérin (BCG). PACV Delayed-type hypersensitivity (DTH) responses were prospectively recorded. Survival was defined as the interval from recurrence to death. Ninety-four patients underwent reinduction immunotherapy. DTH responses to PACV before recurrence increased significantly after reinduction therapy (P =.0001). The median survival time was 37 months for reinduced patients and 17 months for other patients. On multivariate analysis, reinduction status remained a significant prognostic variable (P =.0277). In the reinduction group, there was a significant correlation between PACV DTH responses and survival (P =.0178). Reinduction vaccine regimen can enhance immune responses in previously immunized patients and is associated with prolonged survival after recurrence in patients receiving the same active specific immunotherapy.

Biological therapy of colorectal cancer

In this review, the immunogenicity of colorectal cancer (CRC) and the results of clinical and recent preclinical studies are discussed. Evidence for immune reactivity has been found in several preclinical models and the prognostic value of some of these immune responses have been reported. The possible mechanisms are discussed. Treatment with monoclonal antibodies is still experimental; as previously described benefit of treatment with monoclonal antibodies could not be confirmed. Labelled monoclonal antibody therapy has produced mixed results and also need further investigation. Several antigens are used in active specific immunotherapy (ASI). Its targets and modifications are discussed, as are their use in clinical studies. Although some of the results are promising, the results still have to be confirmed in larger studies. Since there is sufficient evidence for immune reactivity in CRC, further research on immunotherapeutic strategies is justified and will be focused on the development of humanised antibodies, the search for other relevant T-cell epitopes and ways to induce a more effective T cell response.

Induction of a systemic immune response by a polyvalent melanoma-associated antigen DNA vaccine for prevention and treatment of malignant melanoma.

Studies have demonstrated that active-specific immunotherapy has potential for controlling melanoma progression. We developed a polyvalent melanoma gene vaccine using a plasmid vector to deliver the immunogenic human melanoma-associated antigens (MAAs) gp100 and TRP-2. The MAA-containing plasmids were delivered individually in vivo using the hemagglutinating virus Japan (HVJ)-anionic liposome delivery system. C57BL/6 mice were immunized weekly by intramuscular (i.m.) injection or intranasal (i.n.) inoculation for 3 weeks. Although both i.m. and i.n. immunization induced Th1 (T helper) and Th2 cell responses to gp100 and TRP2, the i.m. route induced a better Th1 response. MAA-specific IgG2a, IgG1, and delayed-type hypersensitivity (DTH) responses were induced against both MAAs by i.m. immunization. We assessed the vaccine for its prophylactic and therapeutic effect against the murine B16 F10 melanoma. Animals vaccinated and subsequently challenged with a lethal dose of B16 cells were significantly (P<0.01) protected against tumor progression and had significantly (P<0.01) enhanced survival compared with treatment using control plasmid. We also developed a therapeutic model in which mice were given B16 cells and subsequently immunized with the vaccine or treated with control plasmid. In animals treated with the vaccine, tumor growth was significantly (P<0.01) controlled, and survival was prolonged compared with controls. These studies demonstrate that the polyvalent DNA vaccine induces an effective systemic Th response.

Cancer vaccines: An update with special focus on ganglioside antigens (Review)

Vaccine development is one of the most promising and exciting fields in cancer research; numerous approaches are being studied to developed effective cancer vaccines. The aim of this form of therapy is to teach the patient's immune system to recognize the antigens expressed in tumor cells, but not in normal tissue, to be able to destroy these abnormal cells leaving the normal cells intact. In other words, is an attempt to teach the immune system to recognize antigens that escaped the immunologic surveillance and are by it, therefore able to survive and, in time, disseminate. However each research group developing a cancer vaccine, uses a different technology, targeting different antigens, combining different carriers and adjuvants, and using different immunization schedules. Most of the vaccines are still experimental and not approved by the US or European Regulatory Agencies. In this work, we will offer an update in the knowledge in cancer immunology and all the anticancer vaccine approaches, with special emphasis in ganglioside based vaccines. It has been demonstrated that quantitative and qualitative changes occur in ganglioside expression during the oncogenic transformation. Malignant transformation appears to activate enzymes associated with ganglioside glycosylation, resulting in altered patterns of ganglioside expression in tumors. Direct evidence of the importance of gangliosides as potential targets for active immunotherapy has been suggested by the observation that human monoclonal antibodies against these glycolipids induce shrinkage of human cutaneous melanoma metastasis. Thus, the cellular over-expression and shedding of gangliosides into the interstitial space may play a central role in cell growth regulation, immune tolerance and tumor-angiogenesis, therefore representing a new target for anticancer therapy. Since 1993 researchers at the University of Buenos Aires and the University of Quilmes (Argentina), have taken part in a project carried out by the <Centro de Inmunologia Molecular> (CIM) from La Havana, Cuba, to developed new strategies for specific active immunotherapy. The project included two ganglioside based vaccines and one anti-idiotypic vaccine. We focused on two antigens: first GM3, an ubiquitous antigen which is over-expressed in several epithelial tumor types; and a second one, N-Glycolyl-GM3 a more <tumor specific> molecule, not being expressed in normal tissues and recently found in several neoplastic cells, in particular breast, melanoma and neuroectodermal cancer cells. We developed two vaccines, one with each antigen, both using proteins derived from the outer membrane proteins (OMP) of Neisseria Meningitidis B, as carriers. We developed also the 1E10 vaccine; an anti-idiotype vaccine designed to mimic the N-Glycolyl-GM3 gangliosides. This monoclonal antibody is an Ab2-type-antibody which recognizes the Ab1 antibody called P3, the latter is a monoclonal antibody that specifically recognizes gangliosides as antigens. Since 1998 we initiated a clinical development program for these three compounds. Results of the phase I clinical trials proved that the three vaccines were safe and able to elicit specific antibody responses. In addition we were able to demonstrate the activation of the cellular arm of the immune response in patients treated with the GM3 vaccine. Although phase I trials are not designed to evaluate antitumor efficacy, it was encouraging to observe tumor shrinkage in some patients treated both with the GM3 and N-Glycolyl-GM3 vaccines. We have already begun a phase II program in several neoplastic diseases, with all three vaccines.

T cell memory, anergy and immunotherapy in breast cancer.

T cell immunity in breast cancer is suggested to play a role in tumor dormancy, a period of stability which can correspond to the time interval between primary treatment and tumor recurrence. Bone marrow in breast cancer patients seems to be particularly important because it is highly enriched with cancer specific memory T cells. Similar cells can be found in peripheral blood, but these appear to be functionally anergic. The immune system of primary operated breast cancer patients does not seem to be completely anergized. Bone marrow derived memory T cells can be reactivated ex vivo and show functional reactivity, including tumor rejection in NOD/SCID mice. Promising results were obtained from a postoperative phase-II active specific immunotherapy study. In this study, 32 patients treated with an optimal formulation of a virus-modified autologous tumor vaccine (ATV-NDV) appeared to have a significant 5-year survival benefit. Our results suggest that cancer reactive memory T cells which are enriched in the bone marrow of breast cancer patients, can be activated ex vivo via autologous dendritic cells pulsed with breast cancer tumor antigens, or they can be activated in situ via a tumor vaccine, which combines tumor antigens with virus infection. The findings should encourage further studies in breast cancer on active specific immunotherapy with tumor vaccines or adoptive immunotherapy with activated memory T cells.

Isolation of human tumor-associated cell surface antigen-binding scFvs.

Several approaches have been used to identify antibody (Ab)-defined human tumor-associated antigens (TAA) that can be used for passive and/or active specific immunotherapy of malignant diseases. For example, hybridoma technology has been successfully used to identify TAA recognized by mouse monoclonal Abs (for review, see ref. 1). The SEREX methodology, i.e., serological analysis of recombinant cDNA expression libraries prepared from malignant cells, has also been successfully used to identify TAA recognized by Abs present in sera from patients with malignant diseases (). A number of novel TAA have been identified with the SEREX methodology, but most of them are intracellular (), and are therefore not likely to be useful targets for Ab-based immunotherapy of malignant diseases. More recently, TAA have been identified by utilizing phage-display Ab libraries, which are a diverse collection of Abs displayed as Fabs (,) or scFvs () on the surface of filamentous phages (for review, see ref. 7). Phage libraries have been constructed using a collection of cloned VH and/or VL fragments that have been assembled in vitro with random complementarity-determining region 3 (CDR3) (synthetic libraries) (). Alternatively, phage libraries have been constructed using lymphocytes from either unimmunized (naïve libraries) () or immunized (immune libraries) (,) individuals.

HLA class I expression in primary hepatocellular carcinoma.

To investigate whether CTL vaccine therapy is suitable for primary hepatocellular carcinoma (HCC) from the viewpoint of HLA class I antigens expression. The immunocytochemistry, image analysis, flow cytometry, and labeled streptavidin biotin (LSAB) method of immunohistochemistry were applied respectively to study 4 HCC cell lines (e.g. Alexander, HepG2, SMMC-7721, and QGY-7703) cultured in vitro and 6 frozen tissue specimens of HCC. The positive control cell line Raji had very strong positive staining. Most mitotic and nonmitotic cells of the 4 HCC cell lines had various intensity of HLA class I antigens expression. The negative control cell K562 and the control slides of all the cell lines had no positive staining. In the 6 HCC specimens immunohistochemically studied, histological normal hepatocytes had no or very weak positive staining and the liver sinus had very strong positive staining. Most HCC cells in the sections from the 6 HCC specimens had strong positive HLA classIantigens staining. The positive staining was located in the cytoplasm, the perinuclear area, and at the cell membrane of the liver cancer cells. Flow cytometry also revealed that Raji and those 4 HCC cell lines had strong HLA classIantigens expression, which was confirmed quantitatively by the image analysis. It showed that the objective grayscale values of Raji and those 4 HCC cell lines were significantly different from that of K562 (Raji 114.04+/-10.94, Alexander 165.97+/-5.35, HepG2 167.02+/-12.60, QGY-7703 161.46+/-7.13, SMMC-7721 165.93+/-5.21, K562 244.89+/-4.60, P<0.01). Significant differences were also found between Raji and the 4 HCC cell lines. HCC cells express HLA class I antigens strongly. From this point of view, the active specific immunotherapy of CTL vaccine is suitable and practicable for HCC.

The impact of immune responses on lung cancer and the development of new treatment modalities

Objective: This presentation covers predominantly review data in relation with immune responses initiating and accompanying lung carcinogenesis or- on the contrary-contributing to novel therapeutic developments. Occasionally, personal findings will be considered. Results 1 of immune deficiency: It is known for several decades that cancer incidence (several sites) is increased in subjects receiving immunosuppressive therapy, e.g. to avoid transplant rejection, or suffering from AIDS. We have observed that in areas heavily polluted by industrial activities, resulting in immune deficiency, cancer incidence is increased, notably for lung cancer. On the other hand, neoplastic cells are able to escape the host's immune responses by inducing apoptosis of the effector T lymphocytes. Apoptosis in T-cells is triggered by the interaction of the membrane receptor Fas with its normal ligand Fas L, or an activating antibody. Now lung carcinoma cells have been shown to express Fas L, enabling them to destroy cytolytic T cells. Results 2 of immune treatment: It is well over a century ago that interest in the immunotherapy of cancer was aroused by the observation of tumour regressions concomitant with bacterial infection, an observation leading to the development of ‘Coley's toxin’, a mixture of killed bacteria (presently known to act through the presence of TNF-α). Since these long-standing empirical attempts, a lasting search for immune control of cancer has been initiated, comprising such different approaches as active non-specific immunotherapy, active specific immunotherapy, approaches based on the use of monoclonal antibodies, as well as those depending on cellular immunity and the development of adoptive immunotherapy, and the use of peptide vaccines. These different approaches will be described and their results presented. Conclusion: Present state-of-the-art will be discussed and new pathways for development evoked; better understanding of immune mechanisms is opening new avenues for improved treatment efficacy.

Theratope® vaccine (STn-KLH)

Active specific immunotherapy (ASI) is a promising approach to treating cancer. Numerous studies in the laboratory have demonstrated that various cancer vaccines can stimulate antibody and cell mediated immune responses against tumour-associated antigens [1-9]. Yet few studies have demonstrated convincing clinical responses. Sialyl-Tn (STn) is a carbohydrate associated with the MUC1 mucin on a number of human cancer cells and is associated with more aggressive disease. Consequently, STn is an ideal candidate for ASI therapy. Theratope® vaccine is a cancer vaccine that was designed by Biomira, Inc. (Edmonton, Alberta, Canada) by incorporating a synthetic STn antigen that emulates the carbohydrate seen on human tumours. The clinical trials conducted to date with Theratope® vaccine are outlined in this report. Overall, Theratope® vaccine has been well-tolerated with minimal toxicity. The most common side effects have been induration and erythema at the site of injections. Both in a non-transplant setting following low dose iv. cyclophosphamide and high dose autologous transplant setting, there has been a trend toward Theratope® vaccine decreasing the risk for relapse, prolonging the time to relapse and thus impacting on overall survival. The definitive Phase III trial comparing the outcome of patients with metastatic breast cancer receiving vaccinations with Theratope® vaccine versus vaccination with the nonspecific immune stimulants Keyhole Limpet Hemocyanin (KLH) and Detox™-B stable emulsion (Detox-B) (now called Enhanzyn™ Immunostimulant) was closed to enrolment on March 30, 2001. Over 1000 women with distant metastatic breast cancer were enrolled into the program.

Phase I Study of the BLP25 (MUC1 Peptide) Liposomal Vaccine for Active Specific Immunotherapy in Stage IIIB/IV Non–Small-Cell Lung Cancer

Active specific immunotherapy with liposomal vaccines targeted to the mucinous carcinoma-associated glycoprotein MUC1 have shown promising results in animal models. The aim of this phase I study was to evaluate the safety and immunogenicity of 2 dose levels of the MUC1 liposomal vaccine preparation BLP25. Patients with stage IIIB or IV non–small-cell lung cancer received either 20 μg or 200 μg of the liposomal BLP25 vaccine preparation. Injections were administered subcutaneously at weeks 0, 2, 5, and 9. Immunological responses to vaccination were measured by antibody production, cytotoxic T lymphocytes (CTL), and proliferative T-helper cells. Seventeen patients were entered on study; 12 patients completed the vaccination protocol. Two patients, 1 in each dose group, developed clinically insignificant grade 3 lymphopenia during the study. Nonhematologic toxicities were mild and self-limiting, and there were no significant long-term injection site reactions. Immunological assays revealed the generation of CTLs against MUC1-positive tumor cell lines in 5 of 12 evaluable patients. These patients did not have CTLs prior to receiving the vaccine. No significant humoral response to the vaccination was observed. No objective antitumor responses were observed. Of the 12 patients completing all the vaccinations, 4 had stable disease. Median survival time was 5.4 months in the 20 μg group and 14.6 months in the 200 μg group. In summary, the BLP25 liposomal vaccine was well tolerated and elicited a primarily cellular immune response in these lung cancer patients. This study forms the basis for further clinical exploration of the MUC1 liposomal vaccine, BLP25.

Commentary on “Phase I Study of the BLP25 (MUC1 Peptide) Liposomal Vaccine for Active Specific Immunotherapy in Stage IIIB/IV Non–Small-Cell Lung Cancer”

Commentary on “Phase I Study of the BLP25 (MUC1 Peptide) Liposomal Vaccine for Active Specific Immunotherapy in Stage IIIB/IV Non–Small-Cell Lung Cancer”