Active specific immunotherapy in patients with melanoma. A clinical trial with mouse antiidiotypic monoclonal antibodies elicited with syngeneic anti-high-molecular-weight-melanoma-associated antigen monoclonal antibodies

Chondroitin sulfate proteoglycan 4: An attractive target for antibody-based immunotherapy

Multifunctional molecules involved in tumor progression and metastasis have been identified as valuable targets for immunotherapy. Among these, chondroitin sulfate proteoglycan 4 (CSPG4), a significant tumor cell membrane-bound proteoglycan, has emerged as a promising target, especially in light of advances in chimeric antigen receptor (CAR) T-cell therapy. The profound bioactivity of CSPG4 and its role in pivotal processes such as tumor proliferation, migration, and neoangiogenesis underline its therapeutic potential. We reviewed the molecular intricacies of CSPG4, its functional attributes within tumor cells, and the latest clinical-translational advances targeting it. Strategies such as blocking monoclonal antibodies, conjugate therapies, bispecific antibodies, small-molecule inhibitors, CAR T-cell therapies, trispecific killer engagers, and ribonucleic acid vaccines against CSPG4 were assessed. CSPG4 overexpression in diverse tumors and its correlation with adverse prognostic outcomes emphasize its significance in cancer biology. These findings suggest that targeting CSPG4 offers a promising avenue for future cancer therapy, with potential synergistic effects when combined with existing treatments.

Immunohistochemical detection of the chondroitin sulfate proteoglycan 4 protein in primary and metastatic melanoma

Treatment of malignant melanoma, the most aggressive form of skin cancer, continues to be a major challenge for clinicians. New targeted therapies with kinase inhibitors or drugs which modify the immune response are often accompanied by the development of resistance or severe side effects. In this context, chondroitin sulfate proteoglycan 4 (CSPG4), a highly immunogenic melanoma tumor antigen, could be a potential target for alternative therapeutic approaches. The aim of the present study was to identify differences in the levels of CSPG4 protein expression in primary and metastatic melanomas as well as to analyze correlations between CSPG4 expression and histopathological data and patient characteristics. A total of 189 melanoma tissue samples from Lower Austria, including primary melanomas and melanoma metastases, were immunohistochemically stained for the expression of CSPG4 and statistical analyses were performed. A total of 65.6% of melanoma tissue samples stained positive for the expression of CSPG4. Primary nodular and primary superficial spreading melanomas demonstrated a significantly higher number of positively stained tissue samples for CSPG4 compared with primary lentigo maligna melanomas. No significant differences in the expression of CSPG4 were demonstrated between primary melanomas and melanoma metastases. The present study supports the advancement of the understanding of CSPG4 tissue expression patterns in melanoma patients and provides additional information for further investigation of CSPG4 as a potential therapeutic target.

Anti-cancer pro-inflammatory effects of an IgE antibody targeting the melanoma-associated antigen chondroitin sulfate proteoglycan 4

Outcomes for half of patients with melanoma remain poor despite standard-of-care checkpoint inhibitor therapies. The prevalence of the melanoma-associated antigen chondroitin sulfate proteoglycan 4 (CSPG4) expression is ~70%, therefore effective immunotherapies directed at CSPG4 could benefit many patients. Since IgE exerts potent immune-activating functions in tissues, we engineer a monoclonal IgE antibody with human constant domains recognizing CSPG4 to target melanoma. CSPG4 IgE binds to human melanomas including metastases, mediates tumoricidal antibody-dependent cellular cytotoxicity and stimulates human IgE Fc-receptor-expressing monocytes towards pro-inflammatory phenotypes. IgE demonstrates anti-tumor activity in human melanoma xenograft models engrafted with human effector cells and is associated with enhanced macrophage infiltration, enriched monocyte and macrophage gene signatures and pro-inflammatory signaling pathways in the tumor microenvironment. IgE prolongs the survival of patient-derived xenograft-bearing mice reconstituted with autologous immune cells. No ex vivo activation of basophils in patient blood is measured in the presence of CSPG4 IgE. Our findings support a promising IgE-based immunotherapy for melanoma.

Antigen mimicry as an effective strategy to induce CSPG4-targeted immunity in dogs with oral melanoma: a veterinary trial

BACKGROUND

Melanoma is the most lethal form of skin cancer in humans. Conventional therapies have limited efficacy, and overall response is still unsatisfactory considering that immune checkpoint inhibitors induce lasting clinical responses only in a low percentage of patients. This has prompted us to develop a vaccination strategy employing the tumor antigen chondroitin sulfate proteoglycan (CSPG)4 as a target.

METHODS

To overcome the host's unresponsiveness to the self-antigen CSPG4, we have taken advantage of the conservation of CSPG4 sequence through phylogenetic evolution, so we have used a vaccine, based on a chimeric DNA molecule encompassing both human (Hu) and dog (Do) portions of CSPG4 (HuDo-CSPG4). We have tested its safety and immunogenicity (primary objectives), along with its therapeutic efficacy (secondary outcome), in a prospective, non-randomized, veterinary clinical trial enrolling 80 client-owned dogs with surgically resected, CSPG4-positive, stage II-IV oral melanoma.

RESULTS

Vaccinated dogs developed anti-Do-CSPG4 and Hu-CSPG4 immune response. Interestingly, the antibody titer in vaccinated dogs was significantly associated with the overall survival. Our data suggest that there may be a contribution of the HuDo-CSPG4 vaccination to the improvement of survival of vaccinated dogs as compared with controls treated with conventional therapies alone.

CONCLUSIONS

HuDo-CSPG4 adjuvant vaccination was safe and immunogenic in dogs with oral melanoma, with potential beneficial effects on the course of the disease. Thanks to the power of naturally occurring canine tumors as predictive models for cancer immunotherapy response, these data may represent a basis for the translation of this approach to the treatment of human patients with CSPG4-positive melanoma subtypes.

Immunomodulatory potential of anti-idiotypic antibodies for the treatment of autoimmune diseases

The immune system is a complex network of specialized cells and organs that recognises and reacts against foreign pathogens while remaining unresponsive to host tissues. This ability to self-tolerate is known as immunological tolerance. Autoimmune disease occurs when the immune system fails to differentiate between self and non-self antigens and releases autoantibodies to attack our own cells. Anti-idiotypic (anti-ID) antibodies are important in maintaining a balanced idiotypic regulatory network by neutralising and inhibiting the secretion of autoantibodies. Recently, anti-ID antibodies have been advanced as an alternative form of immunotherapy as they can specifically target autoantibodies, cause less toxicity and side effects, and could provide long-lasting immunity. This review article discusses the immunomodulatory potential of anti-ID antibodies for the treatment of autoimmune diseases.

The immune system protects the body against infections and diseases, such as by producing antibodies. Usually, these antibodies only attack pathogens, leaving healthy cells unharmed. However, autoimmune disease may develop when the immune system mistakenly recognises part of the body as foreign and produces antibodies to attack them. Antibodies that attack our own cells are called autoantibodies. Anti-idiotypic antibodies could be utilized to stop autoantibodies from attacking self cells with minimal side effects and long-lasting immunity. This review discusses anti-idiotypic antibodies usage as an alternative form of immunotherapy to inhibit autoantibodies in autoimmune disease.

Role of cell surface proteoglycans in cancer immunotherapy

Over the past few decades, understanding how tumor cells evade the immune system and their communication with their tumor microenvironment, has been the subject of intense investigation, with the aim of developing new cancer immunotherapies. The current therapies against cancer such as monoclonal antibodies against checkpoint inhibitors, adoptive T-cell transfer, cytokines, vaccines, and oncolytic viruses have managed to improve the clinical outcome of the patients. However, in some tumor entities, the response is limited and could benefit from the identification of novel therapeutic targets. It is known that tumor-extracellular matrix interplay and matrix remodeling are necessary for anti-tumor and pro-tumoral immune responses. Proteoglycans are dominant components of the extracellular matrix and are a highly heterogeneous group of proteins characterized by the covalent attachment of a specific linear carbohydrate chain of the glycosaminoglycan type. At cell surfaces, these molecules modulate the expression and activity of cytokines, chemokines, growth factors, adhesion molecules, and function as signaling co-receptors. By these mechanisms, proteoglycans influence the behavior of cancer cells and their microenvironment during the progression of solid tumors and hematopoietic malignancies. In this review, we discuss why cell surface proteoglycans are attractive pharmacological targets in cancer, and we present current and recent developments in cancer immunology and immunotherapy utilizing proteoglycan-targeted strategies.

Chondroitin Sulfate Proteoglycan 4 and Its Potential As an Antibody Immunotherapy Target across Different Tumor Types

Overexpression of the chondroitin sulfate proteoglycan 4 (CSPG4) has been associated with the pathology of multiple types of such as melanoma, breast cancer, squamous cell carcinoma, mesothelioma, neuroblastoma, adult and pediatric sarcomas, and some hematological cancers. CSPG4 has been reported to exhibit a role in the growth and survival as well as in the spreading and metastasis of tumor cells. CSPG4 is overexpressed in several malignant diseases, while it is thought to have restricted and low expression in normal tissues. Thus, CSPG4 has become the target of numerous anticancer treatment approaches, including monoclonal antibody-based therapies. This study reviews key potential anti-CSPG4 antibody and immune-based therapies and examines their direct antiproliferative/metastatic and immune activating mechanisms of action.

CSPG4: a prototype oncoantigen for translational immunotherapy studies

Thanks to striking progress in both the understanding of anti-tumor immune response and the characterization of several tumor associated antigens (TAA), a more rational design and more sophisticated strategies for anti-tumor vaccination have been possible. However, the effectiveness of cancer vaccines in clinical trial is still partial, indicating that additional studies are needed to optimize their design and their pre-clinical testing. Indeed, anti-tumor vaccination success relies on the choice of the best TAA to be targeted and on the translational power of the pre-clinical model used to assess its efficacy. The chondroitin sulfate proteoglycan-4 (CSPG4) is a cell surface proteoglycan overexpressed in a huge range of human and canine neoplastic lesions by tumor cells, tumor microenvironment and cancer initiating cells. CSPG4 plays a central role in the oncogenic pathways required for malignant progression and metastatization. Thanks to these features and to its poor expression in adult healthy tissues, CSPG4 represents an ideal oncoantigen and thus an attractive target for anti-tumor immunotherapy. In this review we explore the potential of CSPG4 immune-targeting. Moreover, since it has been clearly demonstrated that spontaneous canine tumors mimic the progression of human malignancies better than any other pre-clinical model available so far, we reported also our results indicating that CSPG4 DNA vaccination is safe and effective in significantly increasing the survival of canine melanoma patients. Therefore, anti-CSPG4 vaccination strategy could have a substantial impact for the treatment of the wider population of spontaneous CSPG4-positive tumor affected dogs with a priceless translational value and a revolutionary implication for human oncological patients.

Theranostic impact of NG2/CSPG4 proteoglycan in cancer

NG2/CSPG4 is an unusual cell-membrane integral proteoglycan widely recognized to be a prognostic factor, a valuable tool for ex vivo and non-invasive molecular diagnostics and, by virtue of its tight association with malignancy, a tantalizing therapeutic target in several tumour types. Although the biology behind its involvement in cancer progression needs to be better understood, implementation of NG2/CSPG4 in the routine clinical practice is attainable and has the potential to contribute to an improved individualized management of cancer patients. In this context, its polymorphic nature seems to be particularly valuable in the effort to standardize informative diagnostic procedures and consolidate forcible immunotherapeutic treatment strategies. We discuss here the underpinnings for this potential and highlight the benefits of taking advantage of the intra-tumour and inter-patient variability in the regulation of NG2/CSPG4 expression. We envision that NG2/CSPG4 may effectively be exploited in therapeutic interventions aimed at averting resistance to target therapy agents and at interfering with secondary lesion formation and/or tumour recurrence.

CSPG4-specific immunity and survival prolongation in dogs with oral malignant melanoma immunized with human CSPG4 DNA

PURPOSE

Due to the many similarities with its human counterpart, canine malignant melanoma (cMM) is a valuable model in which to assess the efficacy of novel therapeutic strategies. The model is herein used to evaluate the immunogenicity, safety, and therapeutic efficacy of a human chondroitin sulfate proteoglycan-4 (hCSPG4) DNA-based vaccine. The fact that homology between hCSPG4 and cCSPG4 amino-acidic sequences stands at more than 80% provides the rationale for using an hCSPG4 DNA vaccine in the cMM model.

EXPERIMENTAL DESIGN

Dogs with stage II-III surgically resected CSPG4-positive oral MM were subjected to monthly intramuscular plasmid administration, which was followed immediately by electroporation (electrovaccination) for at least 6, and up to 20, months. The immunogenicity, safety, and therapeutic efficacy of the vaccine have been evaluated.

RESULTS

hCSPG4 electrovaccination caused no clinically relevant local or systemic side effects and resulted in significantly longer overall and disease-free survival times in 14 vaccinated dogs as compared with 13 nonvaccinated controls. All vaccinated dogs developed antibodies against both hCSPG4 and cCSPG4. Seven vaccinated dogs were also tested for a cCSPG4-specific T-cell response and only two gave a detectable interferon (IFN)γ response.

CONCLUSION

Xenogeneic electrovaccination against CSPG4 is able to overcome host unresponsiveness to the "self" antigen and seems to be effective in treating cMM, laying the foundation for its translation to a human clinical setting.

The chrondroitin sulfate proteoglycan (CSPG4) regulates human trophoblast function

INTRODUCTION

Trophoblast growth and invasion of the uterine endometrium are critical events during placentation and are tightly regulated by locally produced factors. Abnormal placentation can result in early miscarriage or preeclampsia and intrauterine growth restriction, leading to impaired fetal and/or maternal health. Chondroitin sulfate proteoglycan 4 (CSPG4) is involved in cancer cell migration and invasion, processes which are critical during placentation but unlike in cancer, trophoblast invasion is highly regulated. CSPG4 expression and function in trophoblast is unknown. We determined CSPG4 expression in human first trimester placenta and implantation sites, and investigated whether CSPG4 influenced proliferation, migration and invasion of a human extravillous trophoblast (EVT) cell line (HTR8/SVneo cells) as a model for extravillous trophoblast (EVT).

METHODS AND RESULTS

Immunoreactive CSPG4 localized to EVT cells in the trophoblast shell, subpopulations of interstitial EVT cells within the decidua and cytotrophoblast cells in placental villi. In HTR8/SVneo cells, siRNA knockdown of CSPG4 stimulated proliferation and decreased migration/invasion. In primary first trimester placental villi explants two cytokines, interleukin 11 (IL11) and leukemia inhibitory factor (LIF) with known roles in trophoblast function, stimulated CSPG4 mRNA expression and immunoreactive protein in the cyotrophoblast.

DISCUSSION AND CONCLUSION

This is the first demonstration of the production and function of CSPG4 in human placentation. These data suggest that locally produced CSPG4 stimulates human EVT migration and invasion and suggests that IL11 and LIF regulate villous cytotrophoblast differentiation towards the invasive phenotype at least in part via CSPG4.

Racotumomab: an anti-idiotype vaccine related to N-glycolyl-containing gangliosides - preclinical and clinical data

Neu-glycolyl (NeuGc)-containing gangliosides are attractive targets for immunotherapy with anti-idiotype mAbs, because these glycolipids are not normal components of the cytoplasmic membrane in humans, but their expression has been demonstrated in several human malignant tumors. Racotumomab is an anti-idiotype mAb specific to P3 mAb, an antibody which reacts to NeuGc-containing gangliosides, sulfatides, and other antigens expressed in tumors. Preparations containing racotumomab were able to induce a strong anti-metastatic effect in tumor-bearing mice. Different Phase I clinical trials have been conducted in patients with advanced melanoma, breast cancer, and lung cancer. The results of these clinical trials demonstrated the low toxicity and the high immunogenicity of this vaccine. The induced antibodies recognized and directly killed tumor cells expressing NeuGcGM3. A Phase II/III multicenter, controlled, randomized, double blind clinical trial was conducted to evaluate the effect of aluminum hydroxide-precipitated racotumomab vaccine in overall survival in patients with advanced non-small cell lung cancer. The clinical results of this study showed a significant clinical benefit in the patients who were treated with the anti-idiotype vaccine.

Functional characterization of an scFv-Fc antibody that immunotherapeutically targets the common cancer cell surface proteoglycan CSPG4

Cell surface chondroitin sulfate proteoglycan 4 (CSPG4) is an attractive target for antibody-based cancer immunotherapy because of its role in tumor cell biology, its high expression on malignant cells including cancer-initiating cells, and its restricted distribution in normal tissues. The clinical use of CSPG4 has been hampered by the lack of a CSPG4-specific chimeric, humanized, or fully human monoclonal antibody. To overcome this limitation, we generated a CSPG4-specific fully human single-chain antibody termed scFv-FcC21 and characterized its specificity and antitumor activity. Viable CSPG4(+) melanoma cells were used in a screen of a human scFv phage display library that included CDR3 engineered to optimize antibody binding sites. The scFv antibody isolated was then recombinantly engineered with a human immunoglobulin G1 Fc region to construct the fully human antibody scFv-FcC21, which recognized tumors of neuroectodermal origin, various types of carcinomas, mesotheliomas, and sarcomas as well as myeloid leukemias. scFv-FcC21 inhibited in vitro growth and migration of tumor cells and in vivo growth of human tumor xenografts. These effects were mediated by inhibition of the activation of extracellular signal-regulated kinase and focal adhesion kinase signaling pathways that are critical for tumor cell growth and migration, respectively. Our findings define the CSPG4-specific fully human scFv-FcC21 antibody as a candidate therapeutic agent to target the many types of tumors that express CSPG4.

Intravenous immunoglobulin-based immunotherapy: an arsenal of possibilities for patients and science

The use of intravenous immunoglobulin (IVIG) concentrated from pooled healthy donors' plasma has gained increasing popularity. IVIG therapy has become important as a replacement therapy in primary and acquired humoral immunodeficiencies, and it has been extended to autoimmune, neurodegenerative and inflammatory conditions and transplantation therapy. Recurrent pregnancy failure and cancer are rather new platforms, where IVIG has shown its beneficial effects. This manuscript is focused on these two off-labelled usages. The immunomodulatory mechanisms of IVIG therapy appear as a coordinated orchestration of different functions, resulting in a synergistic effect. Treatment monitoring and detailed molecular analyses reveal how such treatments may interfere with disease pathogenesis. These finding may foster the development of novel therapeutic and/or preventive strategies. Studying this field with bidirectional bench-to-bedside and bedside-to-bench approaches fit well into 'the two-way road' paradigm of translational medicine.

Overview of mimotopes and related strategies in tumor vaccine development

Tumor vaccine has been studied extensively as an alternative or adjuvant therapy in the treatment of malignant tumors in the hope of prolonging the overall survival rates of cancer patients. The efficacy largely relies on the specificity of the target. In the last decade, many antibody epitopes, called mimotopes, have been revealed as candidates through phage-display technology. These mimotopes do not necessarily consist of amino acid sequences that are identical to the native antigen but they do mimic their structure. Tumor vaccines based on these mimotopes have been proposed as an important developing strategy. Some peptide mimotopes have produced encouraging clinical outcomes. Although most studies are still in the preclinical phase, these findings will possibly pave the way for the development of novel mimotope-based tumor vaccines.

Mimotope vaccines: epitope mimics induce anti-cancer antibodies

Mimotopes are epitope-mimicking structures. When applied for immunizations they induce desired antibody specificities exclusively based on the principle of molecular mimicry. This is important as antibodies directed against tumor-associated antigens may harbor diverse biological effects depending on their epitope specificity. Thus they may inhibit or promote tumor growth. This review gives an update on different vaccination strategies based on the mimotope concept.

Generation of anti-Neu-glycolyl-ganglioside antibodies by immunization with an anti-idiotype monoclonal antibody: A self versus non-self-matter

We have previously generated a murine anti-idiotype (Ab2) monoclonal antibody (mAb) to a murine Ab1 mAb, named P3, which selectively binds Neu-glycolyl (NeuGc)-sialic acid on several monosialo- and disialogangliosides, and also reacts with sulfatides and antigens expressed in human melanoma and breast tumors. This Ab2 mAb, designated as 1E10, induced anti-anti-idiotype antibodies (Ab3) in mice and cancer patients. These Ab3 generated by 1E10 mAb were characterized by bearing P3 mAb idiotopes (Ab3, Id +). But when the specificity of these Ab3 antibodies was tested, no specific humoral response against NeuGc-containing gangliosides was detected in sera from immunized mice. However, hyperimmune sera from melanoma and breast cancer patients vaccinated with this Ab2 mAb were able to react specifically with these gangliosides. The different expression of NeuGc-containing gangliosides in the normal tissues of mice and humans could explain these results. In order to demonstrate these findings in other animal species with a different NeuGc-sialic acid expression, we performed similar studies in monkeys and chickens. In monkeys, as in most mammals, NeuGc-containing gangliosides are self-antigens. In contrast, chickens, like humans, lack the expression of these antigens in normal tissues. Here we report that the antibody response against NeuGc-containing gangliosides induced by immunization with 1E10 mAb was completely different in both species. No specific antibody response against these gangliosides was detected in hyperimmune monkey sera. In contrast, a strong and specific Ab3 response against GM3(NeuGc) and GM2(NeuGc) gangliosides (Ab3, Ag+) was generated in chickens due to the administration of 1E10 mAb.

Human High Molecular Weight Melanoma-Associated Antigen Mimicry by Mouse Anti-Idiotypic Monoclonal Antibody MK2-23: Enhancement of Immunogenicity of Anti-Idiotypic Monoclonal Antibody MK2-23 by Fusion with Interleukin 2

To overcome unresponsiveness to the self-high molecular weight melanoma-associated antigen (HMW-MAA) in hosts with constitutive HMW-MAA expression, we have used as immunogen the anti-idiotypic monoclonal antibody (mAb) MK2-23, which mimics the antigenic determinant recognized by the anti-HMW-MAA mAb 763.74. In a phase I/II clinical trial, anti-idiotypic mAb MK2-23, conjugated to keyhole limpet hemocyanin (KLH) as a carrier and given with Bacillus Calmette-Guerin (BCG) as an adjuvant, elicited HMW-MAA-specific antibodies in about 60% of the immunized melanoma patients. The immune response was associated with survival prolongation. However, safety and standardization issues associated with the use of KLH and BCG in the clinical setting have prompted us to develop alternative immunization strategies. Conjugation of human interleukin 2 (IL-2) to mAb MK2-23 variable regions covalently linked to human immunoglobulin constant regions enhanced mAb MK2-23 immunogenicity in BALB/c mice to an extent similar to that induced by mAb MK2-23 conjugated to KLH and given with Freund's adjuvant. As determined by the level of serum antibodies and delayed-type hypersensitivity responses to HMW-MAA-bearing melanoma cells, immunization of mice with the MK2-23-IL-2 fusion protein elicited more robust humoral and cellular responses, respectively, than immunization with KLH-conjugated mAb MK2-23 and separate administration of IL-2. The immunogenicity of the fusion protein is dependent on IL-2 conjugation, because immunization of mice with either mAb MK2-23 or chimeric mAb MK2-23, in combination with IL-2, was not as effective in eliciting HMW-MAA-specific immune responses. These results suggest that the MK2-23-IL-2 fusion protein represents a useful immunogen to implement active specific immunotherapy in patients with melanoma, because it bypasses the requirement for KLH conjugation and adjuvant administration.

Vaccination with a Human High Molecular Weight Melanoma-Associated Antigen Mimotope Induces a Humoral Response Inhibiting Melanoma Cell Growth In Vitro

Peptide mimics of a conformational epitope that is recognized by a mAb with antitumor activity are promising candidates for formulations of anticancer vaccines. These mimotope vaccines are able to induce a polyclonal Ab response focused to the determinant of the mAb. Such attempts at cancer immunotherapy are of special interest for malignant melanoma that is highly resistant to chemotherapy and radiotherapy. In this study, we describe for the first time the design and immunogenicity of a vaccine containing a mimotope of the human high m.w. melanoma-associated Ag (HMW-MAA) and the biological potential of the induced Abs. Mimotopes were selected from a pVIII-9mer phage display peptide library with the anti-HMW-MAA mAb 225.28S. The mimotope vaccine was then generated by coupling the most suitable candidate mimotope to tetanus toxoid as an immunogenic carrier. Immunization of rabbits with this vaccine induced a specific humoral immune response directed toward the epitope recognized by the mAb 225.28S on the native HMW-MAA. The induced Abs inhibited the in vitro growth of the melanoma cell line 518A2 up to 62%. In addition, the Abs mediated 26% lysis of 518A2 cells in Ab-dependent cellular cytotoxicity. Our results indicate a possible application of this mimotope vaccine as a novel immunotherapeutic agent for the treatment of malignant melanoma.

A phase II trial comparing five dose levels of BEC2 anti-idiotypic monoclonal antibody vaccine that mimics GD3 ganglioside

In previous studies, we showed that immunization with 2.5 mg of BEC2, an anti-idiotypic MAb that mimics GD3 ganglioside, can induce antibodies against GD3 in approximately 25% of patients. In this trial, 50 melanoma patients at high risk for recurrence were randomly assigned to one of the five BEC2 dose levels (2.5 microg-10mg) to determine if lower or higher BEC2 doses are more immunogenic. We also tested whether prolonged booster immunizations can enhance the anti-GD3 antibody response. All patients developed detectable IgG against BEC2 except for one patient at the lowest BEC2 dose level. Six patients developed detectable antibody responses to GD3, all of them at the lower three dose levels of BEC2. We conclude that high doses of BEC2 are not necessary to induce anti-GD3 antibody responses and that lower doses may be more immunogenic than the 2.5 mg dose used in previous BEC2 trials. Prolonged booster immunizations did not induce or maintain antibody responses.

Fine specificity of high molecular weight-melanoma-associated antigen-specific cytotoxic T lymphocytes elicited by anti-idiotypic monoclonal antibodies in patients with melanoma

HLA-A2-restricted CTLs, which lysed high molecular weight (HMW)-melanoma-associated antigen (MAA)(+) melanoma cells, were induced in patients with melanoma immunized with MELIMMUNE, a combination of the murine anti-idiotypic (anti-id) monoclonal antibodies (mAb) MEL-2 and MF11-30 (MW Pride et al., Clin Cancer Res 1998;4:2363.). In the present study we investigated whether CTL epitopes are present in anti-id mAb MF-11-30 and activate T cells to recognize HMW-MAA on melanoma cells. One candidate epitope in the mAb MF11-30 VH chain, VH (3-11), was selected based on the presence of HLA-A2 anchor residues and partial homology with the HMW-MAA epitope, HMW-MAA (76-84). Lymphocytes from HLA-A2(+)-immunized patients proliferated to VH (3-11) peptide and to a variant HMW-MAA peptide to a significantly greater extent than autologous lymphocytes stimulated with an irrelevant peptide and lymphocytes from nonimmunized patients. No proliferative response was detected to the wild-type HMW-MAA peptide (76-84). Significant increase in IFN-gamma production but not in interleukin 10 production in response to VH (3-11) and to variant HMW-MAA peptide (76-84) was observed in lymphocytes from the immunized patients. Stimulation of lymphocytes from HLA-A2(+) patients with the two peptides induced CTL, which lysed HMW-MAA(+)/HLA-A2(+) A375SM melanoma cells. This is the first report documenting the presence of immunogenic peptides in a murine anti-id mAb for a defined epitope expressed by a human melanoma-associated antigen. These results may be relevant for development of novel vaccines based on homology between anti-id mAb and tumor-associated antigen amino acid sequences.

Isolation and characterisation of a human anti-idiotypic scFv used as a surrogate tumour antigen to elicit an anti-HER-2/neu humoral response in mice

HER-2/neu is a tumour antigen that is overexpressed in human breast tumours. Among the vaccine strategies developed to overcome immune tolerance to self-proteins, vaccination with anti-idiotypic (anti-Id) antibodies has been described as a promising approach for treatment of several malignant diseases. To develop an active immunotherapy for cancer patients positive for HER-2/neu, we investigated immunisation with human anti-Id single-chain fragments (scFv) mimicking the conformation of HER-2/neu protein to induce a humoral response in mice. We selected by phage display two human anti-Id scFv (Ab2beta) directed against trastuzumab F(ab')2 fragments (Ab1), a humanised anti-HER-2/neu monoclonal antibody. Using competitive ELISA and Biacore biosensor analysis, we showed that anti-Id scFv 40 and scFv 69 could inhibit HER-2/neu binding to trastuzumab. Following vaccination of BALB/c mice with the soluble or phage-displayed scFv, Ab3 polyclonal antibodies, and among them Ab1' antibodies able to bind HER-2/neu, were detected in the sera of the immunised mice. These results demonstrate that the human anti-Id scFv could act as a surrogate antigen for HER-2/neu. The present study strongly suggests that the novel 30 kDa human mini-antibody could be used as an anti-idiotype-based vaccine formulation to induce an effective humoral response in patients bearing HER-2/neu-positive tumours.

Chimeric Anti-N-Glycolyl-Ganglioside and Its Anti-Idiotypic MAbs: Immunodominance of Their Variable Regions

P3 monoclonal antibody (MAb) is a murine IgM that specifically recognizes N-glycolyl (NeuGc)-gangliosides and sulfatides. It also reacts with antigens expressed in human breast tumors and melanoma. In syngeneic model, P3 MAb is able to elicit a strong anti-idiotypic (Ab2) antibody response, even in the absence of adjuvants or carrier proteins. 1E10 MAb is an anti-idiotypic antibody specific for P3 MAb that has demonstrated anti-tumoral effects in syngeneic and allogeneic animals. Here we report the construction of the human IgG(1) chimeric P3 and 1E10 antibodies, and the evaluation of the maintenance of the main properties of the murine MAbs. Chimeric P3 antibody specifically reacted with GM3(NeuGc) and GM2(NeuGc) gangliosides, and not with their acetylated variants. Also, it strongly recognized the anti-idiotypic 1E10 MAb. Chimeric 1E10 antibody specifically reacted with P3 MAb. Upon immunization of Balb/c mice with both chimeric antibodies, we were able to demonstrate the immunodominance of their variable regions. The anti-idiotypic response induced by both antibodies was strong and in most of the mice was even significantly higher than the anti-isotypic response, despite the fact that 70% of the chimeric molecule is xenogenic with respect to the animal model.

Immune responses in breast cancer patients immunized with an anti-idiotype antibody mimicking NeuGc-containing gangliosides

A phase I clinical trial was conducted in patients with stage III/IV breast cancer who were treated with the anti-idiotype mAb 1E10 specific to an Ab1 mAb able to react specifically with N-glycolyl-containing gangliosides and with antigens expressed on human melanoma and breast carcinoma cells. Patients were treated with 1 or 2 mg of aluminum hydroxide-precipitated 1E10 mAb every other week for six injections. Two patients at each dose were reimmunized 7-9 months after completing the induction phase. In hyperimmune sera from eight of the nine patients who received at least four doses of anti-Id vaccine preparations, strong specific responses were observed both against 1E10 mAb and NeuGc-GM3 ganglioside (Ab3 Id+Ag+). Nonclassical Ab1' antibodies (Id-Ag+) were also elicited by 1E10 mAb vaccine treatment. There were no differences between the two levels of dose tested in relation to toxicity and immunogenicity. No evidence of serious or unexpected effects was observed.

Antibody-based vaccines for the treatment of melanoma

Malignant melanoma remains a difficult clinical problem. Chemotherapy is not effective and immunotherapy has long been contemplated as the preferred approach to this disease. Extensive passive and active immunotherapy trials have been conducted. Active vaccination with whole cells or defined antigens, administered with a panoply of techniques to increase immunogenicity, has yielded inconsistent results. The development of antibody-based vaccines has allowed vaccination without the need for tumor tissue material or purified antigens. The idiotype network theory originally proposed by Lindemann and by Jerne provided the basis for the development of anti-idiotype (anti-Id) antibody vaccines, which mimic the internal image of the epitope targeted for immunization. Preclinical and phase I clinical data are available for various malignancies. In melanoma, some of the anti-Id vaccines have targeted gangliosides. One of these vaccines, TriGem, has been successful in generating a robust and specific humoral immunity in melanoma patients. Phase II data suggest this anti-Id vaccine has clinical activity.

An anti-idiotype vaccine elicits a specific response to N-glycolyl sialic acid residues of glycoconjugates in melanoma patients

We generated the 1E10 gamma-type anti-idiotype mAb (Ab2) specific to an Ab1 mAb able to react specifically with N-glycolyl-containing gangliosides and with Ags expressed on human melanoma and breast carcinoma cells. This Ab2 mAb induced an Ab response in animal models sharing immunochemically defined idiotopes with the Ab1. The treatment of tumor-bearing mice with 1E10 mAb induced a strong antitumor activity. A clinical trial was conducted in 20 patients with advanced malignant melanoma. Patients were treated with six intradermal injections of aluminum hydroxide-precipitated 1E10 anti-Id mAb given at 2-wk intervals. Sixteen of the 17 patients who received at least four doses of the anti-Id vaccine develop Ab3 Abs capable of inhibiting Ab2 binding to Ab1 (Ab3Id+). In contrast to the incapacity of 1E10 mAb to generate Ab3 Abs with the same antigenic specificity as the Ab1 mAb in mice, a very specific and strong Ab3 response against N-glycolyl-containing gangliosides was induced in 16 patients (Ab3Ag+). No evidence of serious or unexpected adverse effects has been observed in this clinical trial. 1E10 anti-Id vaccine was safe, well tolerated, and immunologically effective, with most patients being able to generate a specific immune response against 1E10 and Neu-glycolyl-GM(3) ganglioside.

Assessment of safety and the immune response to the CD4 "internal antigen" mouse anti-idiotypic Mab 16D7 in four patients with SLE

We have analyzed the immune response elicited with the human CD4 internal antigen anti-idiotypic monoclonal antibody 16D7 in four patients with active systemic lupus erythematosus and assessed the safety of the treatment. Patients I and 2 received three 2-mg 16D7 subcutaneous (SC) injections at 3-week intervals and mainly developed IgGI, whereas IgG1, IgG3, and IgG4 were detected in the sera of the other two patients (3 and 4) who received the same amount of 16D7 on days 0, 28, and 70. 16D7-F(ab')2 isotypic determinant-specific antibodies levels, evaluated by sera reactivity with the 16D7-isotype matched anti-idiotypic monoclonal antibody 14D6-F(ab')2, were low or undetectable in patient 1 and became detectable following the first and second boosters in patient 3 and patients 2 and 4, respectively. The highest level was seen in patients 3 and 4. The focusing pattern (spectrotype) of 16D7 idiotypic-specific antibodies suggested that multiple V genes are involved or many somatic mutations occur. Once established, each patient's spectrotype remained stable. Although spectrotype were individually distinct, all four patients produced CD4-specific antibodies, indicating that this response crosses the genetic barrier. Disease relapsed after 11 (patient 2), 40 (patients 3 and 4), and 125 (patient 1) weeks. The lack of side effects and the prolonged periods of disease control (33 and 103 weeks after the last booster) warrants an extension of this study.

Murine monoclonal anti-idiotypic antibody as a surrogate antigen for human Her-2/neu

The anti-idiotypic (Id) monoclonal antibody (MAb) 520C9-6b (IgG1k), raised in syngenic mice against the murine anti-Her2/neu MAb 520C9 (Ab1), functionally mimics a human Her2/neu epitope and serves as a surrogate for the protein antigen. Immunization of allogeneic C57BL/6 mice and rabbits with 520C9-6b (Ab2) induced anti-Her2/neu-specific antibodies that react with antigen-positive SKBr3 cells by ELISA and FACS analysis. The immune sera inhibited binding between Ab1 and Ab2 and vice versa (binding of Ab2 to Ab1), indicating that it was a true anti-anti-Id (Ab3) antibody. The Ab3 sera or purified Ab3 specifically lysed Her2/neu-positive SKBr3 cells, but no significant lysis was observed in antigen-negative LS174T cells in an antibody-dependent cellular cytotoxicity assay. An Id-specific cellular immune response was also demonstrated in an in vitro lymphocyte proliferation assay. Furthermore, a panel of tumor tissues and tumor cells was screened for the presence of the Her2/neu epitope by its reactivity with Ab1 and Ab3 using immunohistochemistry and FACS analysis. Identical results were obtained using either Ab1 or Ab3 (Ab1'). The data indicated that anti-Id 520C9-6b can induce Her2/neu-specific antibody in experimental animals and may serve as a potential network antigen for the treatment of patients bearing Her2/neu-positive tumors.

Anti-idiotype vaccine against cancer

Immunization with anti-idiotype (Id) antibodies represents a novel new approach to active immunotherapy. Extensive studies in animal tumor models have demonstrated the efficacy of anti-Id vaccines in preventing tumor growth and curing mice with established tumor. We have developed and characterized several murine monoclonal anti-Id antibodies (Ab2) which mimic distinct human tumor-associated antigens (TAA) and can be used as surrogate antigens for triggering active anti-tumor immunity in cancer patients. Encouraging results have been obtained in recent clinical trials. In this article, we will review the existing literature and summarize our own findings showing the potential of this approach for various human cancers. We will also discuss where anti-Id vaccines may perform better than traditional antigen vaccines.

Antibodies for neoplastic disease : solid tumors

The ease with which polyclonal, monoclonal, and engineered antibody fragments can be prepared allows access to a series of reagents with high selectivity and affinity. These reagents therefore have long held promise as a means of influencing the growth and spread of malignant disease. Over a number of decades therapeutic antibodies have been developed either as single entities or conjugated to a variety of potential disease-ameliorating agents.

Clinical and immune responses in advanced melanoma patients immunized with an anti-idiotype antibody mimicking disialoganglioside GD2

PURPOSE

To determine immune responses and toxicity to the anti-idiotype vaccine, as well as clinical responses and survival, we initiated a clinical trial for patients with advanced melanoma treated with an anti-idiotype antibody (TriGem) that mimics the disialoganglioside GD2.

PATIENTS AND METHODS

Forty-seven patients with advanced melanoma received either 1-, 2-, 4-, or 8-mg doses of TriGem (Titan Pharmaceuticals Inc, South San Francisco, CA) mixed with QS-21 adjuvant (Aquila Biopharmaceuticals, Inc, Worcester, MA) 100 microg subcutaneously weekly for 4 weeks and then monthly until disease progression. Median age was 57 years, there were 32 men and 15 women, 43% of patients had undergone prior therapy for metastatic disease, 55% had disease confined to soft tissue, and 45% had visceral metastasis.

RESULTS

Hyperimmune sera from 40 of 47 patients showed an anti-anti-idiotype (Ab3) response. Patient Ab3 was truly Ab1' because it specifically bound purified disialoganglioside GD2. The isotypic specificity of the Ab3 antibody consisted of predominantly immunoglobulin (Ig)G, and all IgG subclasses were represented. One patient had a complete response that persisted at 24 months, and 12 patients were stable from 14+ to 37+ months (median, 18+ months). Disease progression occurred in 32 patients on study from 1 to 17 months (median, 5.5 months), and 21 have died at 1 to 16 months (median, 6 months). The Kaplan-Meier-derived overall median survival has not been reached. Median survival has not been reached for the 26 patients with soft tissue disease only and was 13 months for 21 patients with visceral metastasis. Toxicity consisted of local reaction at the site of injection and mild fever and chills.

CONCLUSION

TriGem has minimal toxicity and generates robust and specific IgG immune responses against GD2. Objective responses were minimal, but there may be a favorable impact on disease progression and survival that will require prospective randomized trials.

Retrovirus targeting by tropism restriction to melanoma cells

Targeted vectors will be necessary for many gene therapy applications. To target retroviruses to melanomas, we fused a single-chain variable fragment antibody (scFv) directed against the surface glycoprotein high-molecular-weight melanoma-associated antigen (HMW-MAA) to the amphotropic murine leukemia virus envelope. A proline-rich hinge and matrix metalloprotease (MMP) cleavage site linked the two proteins. The modified viruses bound only to HMW-MAA-expressing cells, as inclusion of the proline-rich hinge prevented viral binding to the amphotropic viral receptor. Following attachment to HMW-MAA, MMP cleavage of the envelope at the melanoma cell surface removed the scFv and proline-rich hinge, allowing infection. Complexing of targeted retroviruses with 2, 3-dioleoyloxy-N-[2(spermine-carboxamido)ethyl]N, N-dimethyl-1-propanaminium trifluoroacetate-dioleoyl phosphatidylethanolamine liposomes greatly increased their efficiency without affecting their target cell specificity. In a cell mixture, 40% of HMW-MAA-positive cells but less than 0.01% of HMW-MAA-negative cells were infected. This approach can therefore produce efficient, targeted retroviruses suitable for in vivo gene delivery and should allow specific gene delivery to many human cell types by inclusion of different scFv and protease combinations.

Specific lysis of melanoma cells by receptor grafted T cells is enhanced by anti-idiotypic monoclonal antibodies directed to the scFv domain of the receptor

Malignant transformation of melanocytes is frequently associated with abnormalities in antigen processing and in human leukocyte antigen class I antigen expression. Here, we evaluated a human leukocyte antigen class I antigen-independent approach to target cytotoxic T lymphocytes to melanoma cells by grafting cytotoxic T lymphocytes with a chimeric receptor that consists of both a domain binding to high molecular weight-melanoma associated antigen and a cellular activation domain. The binding domain is a single-chain antibody fragment (scFv) derived from the monoclonal anti-high molecular weight-melanoma associated antigen antibody 763.74 by phage display techniques. The cellular activation domain is the signaling unit of the FcepsilonRI receptor gamma chain. Both domains constitute the chimeric receptor scFv763.74-gammaR. Cytotoxic MD45 T cells grafted with the scFv763.74-gammaR receptor bind specifically to high molecular weight-melanoma associated antigen-positive melanoma cells and lyse melanoma cells in a human leukocyte antigen class I independent fashion. Pre-incubation of receptor grafted T cells with immobilized anti-idiotypic (id) monoclonal antibody MK2-23 binding to the scFv domain of the receptor enhanced the lysis of melanoma cells indicating that the specific cytolytic activity of receptor grafted T cells can be increased by costimulation with cross-linked anti-idiotypic monoclonal antibodies that recognize the antigen binding domain of the chimeric receptor.

Limited Diversity of Human scFv Fragments Isolated by Panning a Synthetic Phage-Display scFv Library with Cultured Human Melanoma Cells

To broaden the specificity of the Abs recognizing human melanoma-associated Ags (MAAs), we have isolated human single-chain fragment of the V region (scFv) fragments by panning the synthetic phage Ab library (#1) with the human melanoma cell lines S5 and SK-MEL-28. All of the isolated scFv fragments reacted with the mouse mAb defined high molecular weight melanoma-associated Ag (HMW-MAA). scFv #70 immunoprecipitates the two characteristic subunits of HMW-MAA, while scFv #28 only immunoprecipitates its large subunit. These results challenge the current view regarding the structure of HMW-MAA and indicate that it consists of two independent subunits. The human scFv fragments share some similarities with the mouse anti-HMW-MAA mAb. Like mAb 149.53 and 225.28, scFv #28 reacts with rat B49 neural cells that express a homologue of HMW-MAA. scFv #70 reacts with a determinant that is spatially close to the one identified by mAbs 149.53, VT68.2, and VT86. Besides suggesting similarities in the recognition of human melanoma cells by the mouse and human Ab repertoire, these results indicate that the Abs isolated from synthetic Ab libraries resemble those that are found in natural Ab repertoires. The restricted diversity of the scFv fragments that were isolated by panning synthetic Ab libraries with different melanoma cell lines suggests that certain Ags, like HMW-MAA, are immunodominant in vitro. This phenomenon, which parallels the in vivo immunodominance of certain Ags, implies that the antigenic profile of the cells used for panning determines the specificity of the preponderant population of isolated Abs.

Tissue distribution of a melanoma-associated antigen D-1 immunogenic in patients with melanoma

A human melanoma-associated antigen D-1 was recently identified by screening an expression cDNA library derived from mRNA of cultured melanoma cells with sera of melanoma patients. The aim of this study is to present in vivo expression and precise distribution of D-1 in normal tissues and benign or malignant neoplasms. By in situ hybridization, we found that the D-1 mRNA was exclusively expressed in the cytoplasms of melanoma cells, but not in keratinocytes, fibroblasts and lymphocytes adjacent to melanoma nests. Further immunohistochemical studies revealed that the expression of D-1 antigen was distributed to both the surface and cytoplasm of melanoma cells, indicating that D-1 antigen can be recognized by killer T lymphocytes or antibodies in vivo. No significant mRNA nor peptide of D-1 was detected in basal cell carcinoma, squamous cell carcinoma and other benign tumors such as melanocytic nevi and seborrheic keratosis. We also confirmed that D-1 mRNA and peptide were not expressed in normal organs by dot blot hybridization and western blot analysis, respectively. These results will assess the suitability of recombinant D-1 protein to implement active specific immunotherapy against melanoma.

Prolonged survival associated with immune response in a patient treated with Lym-1 mouse monoclonal antibody

A patient with aggressive, chemotherapy-resistant non-Hodgkins lymphoma (NHL) was treated with 131I-Lym-1, a mouse antibody, on a protocol designed for serial therapy. Human anti-mouse antibody (HAMA) developed within 1 month of initial therapy. The patient also developed an antibody to the hypervariable region of the Lym-1 antibody (Lym-1 specific). Because the patient was responding to therapy, plasmaphoresis was used to reduce the level of HAMA followed by unlabeled Lym-1 calculated to be sufficient to block residual HAMA. This allowed additional therapy on three subsequent occasions over 5 months. Despite very high HAMA levels, no untoward effects from administrations of Lym-1 were observed. The HAMA response of the patient included anti-Lym-1 specific antibodies containing anti-idiotypic antibodies. The anti-Lym-1 antibody level has been sustained over the 9 year interval since 131I-Lym-1 therapy and has been associated with a uniquely long remission of the patient's disease. These observations demonstrate that, under certain circumstances, radioimmunotherapy (RIT) can be given safely and effectively despite HAMA. Anti-idiotypic antibodies could have induced an immune cascade that contributed to the prolonged disease-free survival of the patient.

Distinct Classes of Chaperoned IL-6 in Human Blood: Differential Immunological and Biological Availability

Transport of IL-6 in blood is fundamental to the biology of this cytokine. In the present study, IL-6 transport, immunological reactivity, and biological availability were investigated in blood from melanoma patients subjected to different active specific immunization regimens (an anti-idiotypic mAb immunization protocol (mAb-keyhole limpet hemocyanin (KLH)-Calmette-Guérin bacillus (BCG), an autologous anti-cancer vaccine protocol (AAAP), or both). Sera were subjected to Sephadex G-200 gel filtration chromatography, and the structure and biological activity of IL-6 complexes in the eluate fractions were probed using five IL-6 ELISAs and two bioassays. Sera from patients administered mAb-KLH+BCG followed by AAAP contained three distinct classes of IL-6 eluting at 30, 200, and 450 kDa, each with its characteristic ELISA reactivity and bioactivity: the 30- and 450-kDa complexes were bioactive in the B9 and Hep3B assays, but the 200-kDa complex was not. The 30- and 450-kDa IL-6 complexes were preferentially reactive in the 7IL6/5IL6 ELISA, the 200-kDa IL-6 complexes were preferentially reactive in the 4IL6/5IL6 ELISA, while the three commercial ELISAs (R&D, Endogen, and Genzyme) detected essentially only the 30-kDa IL-6. In contrast, 1) sera from AAAP patients contained biologically active 30- and 450-kDa IL-6 complexes, while 2) sera from mAb-KLH+BCG patients contained 200-kDa IL-6 complexes inactive in ex vivo bioassays. Both the 450- and 200-kDa complexes included soluble IL-6R, with the 200-kDa complexes additionally containing ligand-occupied anti-IL-6 and anti-soluble IL-6R IgG. The data indicate the existence of specific mechanisms that regulate the transport and function of IL-6 in vivo.

Common cancers--immunotherapy and multidisciplinary therapy: Parts III and IV

The refractoriness of many solid tumors to cytotoxic chemotherapy has led to the exploration of new therapeutic modalities, including immunotherapy. Immunotherapy does not have a direct cytotoxic effect on the cancer cell but is an attempt to promote rejection of the tumor by the host, chiefly through the cellular arm of the immune system. The clinical success with immunotherapy (primarily adoptive immunotherapy) among patients with unresectable malignant melanoma and cancer of the kidney has not been marked by the large numbers of patients responding but by occasional dramatic effectiveness of therapy for these cancers, which usually are refractory to chemotherapy. Long-lasting responses and even complete disappearance of all known metastases are possible for a small percentage of patients with melanoma or renal cell carcinoma who undergo immunotherapy. A reasonable approach for patients with good performance status (no symptoms or ambulatory with symptoms but not bedridden) is entrance to clinical trials, especially trials examining adoptive or active immunotherapy for melanoma or adoptive immunotherapy for renal cancer. The overall treatment of patients with cancer has changed. Primary-care physicians detect almost all cancers. The days when "taking it out" is the best we could offer a patient are over. As we learn more about the use of adjuvant or neoadjuvant chemotherapy and radiation therapy, it is likely one or both of these modalities will be incorporated into the treatment of additional solid tumors previously managed solely with surgical resection. Increasingly, additional therapy is being given for earlier-stage disease as we define how to maximize the potential for cure with minimal toxicity. Many new therapies are on the horizon, including the use of noncytotoxic treatments as an adjunct to a surgical procedure. Such therapies include the use of angiogenesis inhibitors, tumor vaccines, and immunotherapy. Now and in the future, patients will be best served when treated in an environment that can integrate medical, surgical, and radiation oncology actively.

Increased survival of patients treated with a vaccinia melanoma oncolysate vaccine: second interim analysis of data from a phase III, multi-institutional trial

OBJECTIVE

The efficacy of vaccinia melanoma oncolysate (VMO) vaccine to increase overall survival and disease-free survival of patients with surgically resected International Union Against Cancer (UICC) stage II melanoma was studied in a phase III, randomized, multi-institutional trial.

SUMMARY BACKGROUND DATA

Phase I and II trials with VMO showed minimal toxicity and clinical efficacy in patients with melanoma. In a recently completed phase III VMO trial, the first interim analysis performed in April 1994 showed an increasing trend in the survival of patients treated with VMO. The second interim analysis was performed in April 1995.

METHODS

Patients with surgically resected stage II (UICC) melanoma were treated with VMO (N = 104) or placebo vaccinia vaccine virus (V) (N = 113) once a week for 13 weeks and then once every 2 weeks for a total of 12 months. Patients' clinical data were collected as of May 1995 and analyzed for survival.

RESULTS

In this second interim analysis, the mean follow-up time is 42.28 months. No survival difference was observed between VMO and V treatments. However, in a retrospective subset analysis, a subset of males between the ages of 44 and 57 years and having one to five positive nodes (at 2-, 3-, and 5-year intervals, 13.6%, 15.9%, and 20.3% difference insurvival in favor of VMO [N = 20] when compared to V [N = 18] [p = 0.037]) and another subset of patients with clinical stage I (at 3- and 5-year intervals, 30% and 7% difference in survival in favor of VMO [N = 20] when compared to V [N = 23], [p = 0.05]) showed significant survival advantage with VMO.

CONCLUSIONS

Although VMO vaccine therapy in surgical adjuvant setting did not produce a significant survival benefit to all patients with melanoma, patients from the above two subsets had significant survival benefit.

Autoantibodies to tyrosinase: the bridge between melanoma and vitiligo

BACKGROUND

Tyrosinase is an enzyme that participates in the process of melanin production in normal melanocytes and melanoma cells. Enzymes are known to be autoantigens in various autoimmune disorders; thus, after the detection of antityrosinase antibodies in patients with vitiligo and melanoma, tyrosinase was defined as an autoantigen in these conditions. In some patients with melanoma the disease is associated with the appearance of "vitiligo-like" white patches on the skin, called melanoma-associated hypopigmentation (MAH). In this article, the authors summarize the recent data related to antityrosinase antibodies and expand on their role in the pathogenesis of vitiligo, melanoma, and MAH. In addition, the beneficial clinical applications of antityrosinase antibodies are presented.

METHODS

An enzyme-linked immunoadsorbent assay to detect the antityrosinase antibodies in the serum of patients and healthy volunteers was established using mushroom tyrosinase. Employing this method, antityrosinase antibodies were analyzed in a diverse group of patients with melanoma and vitiligo and in mice immunized with tyrosinase.

RESULTS

In patients with melanoma, those with metastatic disease had a higher titer of antityrosinase antibodies compared with healthy subjects, whereas patients with MAH and those with no evidence of disease had similar titers to the control group. The titer of antityrosinase antibodies in patients with metastatic melanoma treated by vaccination with antiidiotypic antibodies mimicking the high molecular weight melanoma-associated antigen (HMW MAA) initially increased after the vaccination and then decreased. High titers of antityrosinase antibodies were detected in patients with diffuse vitiligo compared with patients with localized disease and with the healthy control group. Mice immunized with tyrosinase generated a high titer of antityrosinase antibodies and after the inoculation of melanoma cells developed a lower number of lung metastases compared with an unvaccinated control group.

CONCLUSIONS

The appearance of antityrosinase autoantibodies in the serum of patients with metastatic melanoma and diffuse vitiligo is characterized by these two pathologies. The changes in the serum level of these autoantibodies in patients with melanoma after immunization with another antigen (HMW MAA) may have diagnostic and therapeutic implications.

Advances in dermatologic surgery

The major advances in dermatologic surgery for this period reside in the areas of diagnosis and management of cutaneous melanoma, laser surgery, tumescent liposuction, and tumorigenesis. A closer look at these advances is presented.