Prolongation of survival in metastatic melanoma after active specific immunotherapy with a new polyvalent melanoma vaccine

Biological and clinical developments in melanoma vaccines

The identification of antigens recognised on human tumours by autologous T-lymphocytes has opened the way for vaccination strategies involving defined tumour antigens. These vaccinations are therapeutic, i.e. they involve patients with detectable disease. Tumour regressions have been observed in a minority of melanoma patients in Phase I/II trials. Some of these regressions have been complete and long lasting. Improving the efficacy of therapeutic vaccines will critically depend on their capacity to trigger a robust immune response, on the development of appropriate methods to monitor these antitumour immune responses to vaccination and on a better understanding of the mechanisms used by tumours to escape immune attack. Finally, the initiation of large randomised Phase III trials will determine the impact of these vaccines on melanoma treatment.

Serum TA90 antigen-antibody complex as a surrogate marker for the efficacy of a polyvalent allogeneic whole-cell vaccine (CancerVax) in melanoma

INTRODUCTION

TA90 is a tumor-associated 90-kD glycoprotein antigen expressed on most melanoma cells, including those of CancerVax, a polyvalent allogeneic whole-cell vaccine. Previous studies have shown that a TA90 antigen-antibody immune complex (IC) in the serum of patients with melanoma is a marker of subclinical tumor burden and a strong prognostic factor. We hypothesized that the induction of TA90-IC during postoperative adjuvant CancerVax therapy might indicate vaccine-mediated immune destruction of subclinical melanoma cells with release of TA90, and thereby serve as a surrogate marker of vaccine efficacy.

METHODS

From 1993 to 1997, 219 melanoma patients were enrolled in a prospective phase II trial of CancerVax plus bacille Calmette-Guerin (BCG) after complete tumor resection. Coded serum samples were prospectively collected and analyzed for TA90-IC before and 2, 4, 8, 12, and 16 weeks after initiation of CancerVax therapy. TA90-IC seroconverters were those patients whose negative TA90-IC values (< .410) became positive (> or = .410) after initiation of CancerVax treatment.

RESULTS

Before CancerVax therapy, 51 patients had positive TA90-IC values and 168 patients had negative TA90-IC values. During CancerVax treatment, all 51 positive patients remained positive, 79 (47%) negative patients seroconverted to positive, and 89 (53%) negative patients remained negative. Seroconverters had higher 2-year rates of disease-free survival (59% vs. 32%; P < .006) and overall survival (78% vs. 63%; P < .02) than did patients whose TA90-IC values remained positive.

CONCLUSIONS

CancerVax induces TA90-IC in melanoma patients with subclinical disease. TA90-IC seroconverted patients have significantly improved disease-free and overall survival compared with TA90-IC positive patients. TA90-IC is an important prognostic factor that can serve as a surrogate marker for the clinical efficacy of CancerVax.

Adjuvant active specific immunotherapy of stage II and stage III colon cancer with an autologous tumor cell vaccine: first randomized phase III trials show promise

We performed three multi-institutional, prospectively randomized, controlled clinical trials, assessing the therapeutic effect of post-resection adjuvant active specific immunotherapy in patients with stage II and stage III colon cancer. In each study four outcomes were considered: time-to-disease recurrence, overall survival intervals, disease-free survival intervals, and recurrence-free survival intervals using the Kaplan-Meir method for generating curves and the log-rank test used to compare efficacy distributions. In addition, a meta-analysis of the three phase III trials was performed since the trials had proven homogeneity. Two main analyses were performed: (1) the intent-to-treat colon cancer patients from all three studies; and (2) analyzable colon cancer patients in all three studies. The conclusion of these analyses is that adjuvant active specific immunotherapy provided significant clinical benefits in patients with stage II colon cancer and appears to be an important new adjuvant treatment for these patients.

Melanoma inhibitory activity (MIA), a serological marker of malignant melanoma

Melanoma inhibitory activity (MIA) was originally identified as an 11 kDa protein secreted from malignant melanoma cells. We have shown that MIA is strongly expressed in melanoma and melanoma cell lines but not in melanocytes and normal skin. We also observed that MIA mRNA expression correlates with progressive malignancy of melanocytic tumors. Measuring MIA in serum or plasma by a sensitive and quantitative ELISA and investigating the potential of MIA serum levels as a novel marker for malignant melanomas showed that the protein can be used to monitor therapy and follow-up. The present study measured the variations in blood concentrations of MIA in 84 patients with stage II-IV melanoma by ELISA. Patients treated with repeated injections of a polyvalent melanoma vaccine (PMV), interferon-alpha-2b (IFN-alpha 2b) or interleukin-2 (IL-2) were followed during treatment duration. Before treatment, patients treated with PMV or IFN-alpha 2b had comparable low MIA concentrations, whereas most IL-2-treated patients had higher MIA levels. At the end of treatment, MIA concentrations were higher in patients with progressive disease (PD) than in patients with no clinical evidence of melanoma (NPD) for PMV, IFN-alpha 2b or IL-2 therapy (3.7 +/- 0.2 vs 11.5 +/- 5.4 ng/ml, 3.8 +/- 0.2 vs 8.3 +/- 1.7 ng/ml, and 2.3 +/- 0.7 vs 20.2 +/- 7.4 ng/ml, respectively, p < 0.05). In contrast to the stable MIA concentrations measured in NPD patients, significant increase in MIA levels were observed in PD patients over time regardless of treatment. For PMV- and IFN-alpha 2b-treated patients, a rise in MIA levels occurred significantly earlier than clinical diagnosis of melanoma recurrence. In conclusion, our data suggest that quantitation of MIA serum levels may be used for detection of both clinically apparent and non-apparent metastatic melanoma disease and for monitoring therapy.

Detection of occult melanoma cells in paraffin-embedded histologically negative sentinel lymph nodes using a reverse transcriptase polymerase chain reaction assay

PURPOSE

Detection of occult metastasis before the development of clinical disease could allow more accurate staging, appropriate follow-up procedures, and adjuvant therapies in patients with malignant melanoma (MM). The sentinel lymph node (SLN) has been proposed as a reliable predictor of metastatic disease in the lymphatic basin draining the primary melanoma. In this study, we screened both paraffin-embedded SLNs and peripheral-blood (PB) samples from MM patients at various stage of disease using a multimarker reverse transcriptase polymerase chain reaction (RT-PCR) assay. The prognostic significance of the presence of PCR-positive markers was also evaluated.

PATIENTS AND METHODS

Total RNA was obtained from paraffin-embedded SLN sections and PB samples of 75 MM patients. RT-PCR was performed using tyrosinase and MelanA/MART1 as melanoma-associated markers. Radiolabeled PCR products were analyzed on denaturing polyacrylamide gels.

RESULTS

Good sensitivity of the RT-PCR assay on archival tissues was demonstrated after comparison of RT-PCR results on frozen and paraffin-embedded SLNs from 16 MM patients. Significant correlation between the disease stage and marker expression in both PB and SLN samples was observed; the highest value was for patients who were positive for both markers in SLN (P =.006). Progression of disease was significantly associated with the total number of PCR-positive markers in both PB (P =.034) and SLN (P =.001) samples.

CONCLUSION

Although sensitivity is lowered by the use of paraffin-embedded specimens, our data indicate that RT-PCR analysis of serial sections from archival SLNs may be helpful in improving detection of occult micrometastases, thus improving staging of patients with melanoma.

Tumor-associated antigen TA90 immune complex assay predicts recurrence and survival after surgical treatment of stage I-III melanoma

PURPOSE

Immune complexes (IC) containing the tumor-associated antigen TA90 can be identified in the sera of melanoma patients. We have shown that an enzyme-linked immunosorbent assay for TA90-IC can detect subclinical metastasis before surgical treatment of early-stage melanoma. We assayed the TA90-IC levels of postoperative sera from patients with melanoma and evaluated their relationship to recurrence and survival.

PATIENTS AND METHODS

Multiple archival serum samples prospectively collected during postoperative surveillance of 166 patients with American Joint Committee on Cancer stage I, II, or III melanoma were analyzed for TA90-IC in a blinded fashion. Results were correlated with disease recurrence and survival determined by database and chart review.

RESULTS

TA90-IC status in the early postoperative period was strongly correlated with survival. Five-year overall survival rates were 84% for TA90-IC-negative patients and 36% for TA90-IC-positive patients (P =.0001). Respective 5-year disease-free survival rates were 74% and 24% (P =.0001). The TA90-IC assay was a significant predictor of survival for both stage II and III patients. Multivariate analysis identified TA90-IC status as the strongest independent prognostic factor for both overall and disease-free survival. The TA90-IC assay was elevated in 54 (77%) of 78 patients who developed recurrent disease, becoming positive 19 +/- 7 months before clinical evidence of recurrence. Overall, the assay detected recurrence with a sensitivity of 78% and specificity of 77%. Exclusion of patients receiving postoperative immunotherapy with a polyvalent melanoma cell vaccine increased sensitivity and specificity to 92% and 86%, respectively.

CONCLUSION

The TA90-IC assay can accurately predict survival and detect the presence of subclinical disease after surgery for melanoma, which should be useful in selecting patients for adjuvant therapy. Because the TA90-IC assay detected recurrence on an average of 19 months sooner than did routine clinical and radiographic evaluation, it may allow more timely therapeutic interventions.

Quantitation of HLA-A*0201 bound tumor associated antigens on a peptide pulsed B cell line

CTLs recognize 8- to 10-mer peptides on MHC class I molecules. Recent studies have shown that human CTLs kill autologous tumor cells in an HLA-restricted and peptide-specific manner, and that artificial pep- tides can stimulate tumor-specific CTLs both in vitro and in vivo. Accordingly, several human clinical trials using such peptides are ongoing worldwide. In such methods, the amount of peptide-MHC complexes that remain on the cell surface of APCs after peptide administration is crucial, because CTL activation depends on the number of ligated TCRs and co-stimulation. However, it remains uncertain how many peptide-MHC complexes are reconstituted and remain on live cells after peptide administration. We herein examined the binding affinities of five HLA-A*0201 restricted peptides-four TAAs and one HIV antigen-to HLA-A*0201 molecules and their decay rates on a live B cell line using tandem mass spectrometry. Our experiments showed that nearly 10(5) peptide-MHC complexes per cell could be reconstituted on a cell surface by pulsing a high dose of peptide even if the binding affinities were intermediate or low. However, the decay rates observed for these pep- tide-MHC complexes on a B cell line were faster than previously estimated.

Allogeneic whole-tumour cell vaccination in the rat model of prostate cancer

OBJECTIVE

To investigate cancer immunotherapy using whole allogeneic (differing tissue-type) tumour cells as vaccines in the rat prostate cancer model. Materials and methods Two rat models of prostate cancer were used; MAT-LyLu tumours which grow in Copenhagen rats and PAIII tumours which grow in Lobund-Wistar rats, with crossover of the cell lines to test allogeneic vaccination. The cell lines were immunologically characterized by flow cytometry. Irradiated tumour cells were administered as subcutaneous vaccines either before tumour challenge or after tumour establishment (both subcutaneous). A preparation of heat-killed Mycobacterium vaccae bacilli (SRL172) was used as an adjuvant to increase vaccine efficiency.

RESULTS

Flow cytometry analysis of the cell lines showed that the PAIII cells had higher levels of major histocompatibility complex (MHC) class I and intercellular adhesion molecule (ICAM-1) expression than the MAT-LyLu cells. However, both tumour cell lines were rejected in their allogeneic hosts. Prophylactic vaccination with allogeneic MAT-LyLu cells protected against PAIII tumour challenge in Lobund-Wistar rats, with 80% of animals surviving for > 5 months, compared with 40% for animals receiving autologous cells. The immunity was prolonged, as rats were protected when rechallenged 5 months later. In Copenhagen rats allogeneic PAIII cells protected against the more aggressive MAT-LyLu tumour challenge only when the cells were combined with SRL172. Initial therapy experiments showed that vaccination with the cell lines mediated only limited tumour regression in the Lobund-Wistar rats.

CONCLUSION

The allogeneic tumour cell vaccination model described is valuable for assessing the principle and efficacy of allogeneic prostate cancer cell vaccines for clinical use.

Autologous, allogeneic tumor cells or genetically engineered cells as cancer vaccine against melanoma

Melanoma is a prototype of immunogenic tumor to which various types of immunotherapy have been applied extensively over the past decades. Melanoma vaccines are designed for the purpose of immune modulation and subsequent anti-tumor effects in the process of an active specific immunotherapy. Previous attempts of these vaccines include immunization with whole tumor cells/cell lysates admixed with nonspecific adjuvants. While these vaccines generated enhanced anti-tumor immunity in a subset of patients, some of which showing prolonged survival compared to historical controls, no clinical benefit has so far been demonstrated in a properly controlled phase III study. New-generation melanoma vaccines, which are based on genetic modifications of tumor cells to express cytokines, generated long-lasting systemic anti-tumor immunity in animal models. Translation of these preclinical results primarily into melanoma patients with advanced diseases, shows the potential of these vaccines to induce systemic anti-tumor immune responses and in some instances tumor regression with acceptably low toxicity. Higher efficacy of this novel vaccine approach would be expected when used in a postsurgical adjuvant setting when the tumor load is small. Also other novel vaccine approaches such as dendritic cell-based therapy hold promise for the treatment of melanoma. But the clinical value of all these new approaches has to be analysed in prospectively randomized clinical studies.

Advances in specific immunotherapy of malignant melanoma

Management of malignant melanoma continues to present a challenge to dermatologists, particularly in advanced cases. In light of the steady increase in the worldwide incidence and mortality rates for melanoma, better understanding of the immune mechanisms regulating melanoma progression and interaction with the host's immune system seems eminently important. New studies on the role of immune mechanisms in the pathogenesis and clinical course of melanoma have recently been published. We review the immune mechanisms involved in tumor progression and ways in which these mechanisms may be applied toward immunotherapeutic management of malignant melanoma.

LEARNING OBJECTIVE

After the completion of this learning activity, participants should be familiar with (1) the immune mechanisms involved in host-tumor interaction and tumor rejection, (2) factors allowing the escape of melanoma cells from immune recognition, and (3) the current rationale for the different types of specific immunotherapy in melanoma. Better understanding of basic mechanisms in tumor immunology should raise awareness of future immunotherapeutic approaches in patients with melanoma, particularly in those who are at high risk of recurrence or who present with advanced disease.

Skin tests predict survival after autologous tumor cell vaccination in metastatic melanoma: experience in 81 patients

BACKGROUND

Currently there is no standard adjuvant treatment following surgical resection of metastatic melanoma. We investigated whether surgery followed by autologous tumor cell-BCG vaccination was beneficial for malignant melanoma patients. In this study we focus on the prognostic value of DTH response following vaccination therapy.

PATIENTS AND METHODS

Eighty-one patients with AJCC stage III and IV melanoma were selected. Whenever feasible, radical metastasectomy was performed. ASI was initiated by the administration of three weekly intra-cutaneous vaccinations with 10(7) irradiated autologous tumor cells, starting four weeks after surgery. Depending on the size of DTH response to the first three injections, subsequent vaccinations were planned. The first two vaccines also contained 10(7) BCG organisms as an immune stimulatory adjuvant.

RESULTS

Induration as well as erythema correlated strongly with survival (P < 0.0001 and P = 0.0004). After radical metastasectomy in stage III melanoma patients a five-year survival of 48% was observed. In stage IV disease, a five-year survival of 34% was seen, after radical surgery had been performed. When macroscopic disease was present at start of vaccination treatment, no clinical responses occurred. Apart from transient skin ulceration at the site of BCG-containing vaccinations, no serious side effects were observed.

CONCLUSIONS

This study shows that large-scale preparation of autologous melanoma cell vaccines is feasible. while vaccination results in DTH responses that correlate significantly with survival. ASI seemed to be beneficial in stage III and stage IV melanoma when given in the adjuvant setting, while causing only very mild side effects.

Vaccination for melanoma

Our knowledge of the immune system has grown tremendously in the 50 years since Coley used bacteria in an attempt to create a vaccine for cancer. The strategy for cancer vaccines has developed in that time as well. Both clinical and laboratory evidence suggests that melanoma is the more immunogenic of solid tumors. If treated early, melanoma can be controlled with surgery, but many patients continue to die from it. With our increased understanding of the immune system's interaction with melanoma, many clinical trials of melanoma vaccines are now underway. Vaccines designed to treat metastatic melanoma have shown some evidence of clinical effectiveness. This article outlines the current status of melanoma vaccination.

Antigen-specific cancer immunotherapy using a GM-CSF secreting allogeneic tumor cell-based vaccine

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-transduced autologous tumor cell-based vaccines are currently one of the major forms of cancer vaccines. However, the preparation of GM-CSF-transduced autologous tumor vaccines is time-consuming and technically challenging. In addition, the host antigen presenting cells, rather than the tumor vaccine cells themselves, present tumor-specific antigens and prime the host T cells. Therefore, we tested the efficacy of antigen-specific allogeneic tumor vaccines. We used human papillomavirus 16 (HPV-16) E7 protein as a model tumor antigen, which is associated with the development of most cervical carcinoma. B16, a C57BL/6 (H-2(b)) derived melanoma cell line, was genetically engineered to produce GM-CSF alone (B16GM), HPV-16 E7 alone (B16E7), or both (B16GME7). These vaccine cells were injected into BALB/c (H-2(d)) mice (10(6) cells/mouse). Two weeks later, mice were challenged with 10(5) live HPV-16 E7(+) BL-1 (H-2(d)) tumor cells and monitored for tumor progression twice weekly. To determine the effective cell population in the antitumor immunity elicited by B16GME7, we carried out in vivo antibody depletion experiments using CD4 and CD8 specific antibodies. In addition, as a measure of the immune responses produced by B16GME7, we performed an in vitro cytotoxic T lymphocyte assay using a standard chromium release method. We found that all of the mice vaccinated with B16GME7 remained tumor free 49 days post-BL-1 challenge. In contrast, mice vaccinated with B16GM and B16E7 did not show any tumor protection against a similar dose of BL-1 cells. Furthermore, the antitumor immunity produced by B16GME7 was dependent on both CD4 and CD8 T cells. In addition, E7-specific cytotoxic T lymphocyte activity could be readily demonstrated in mice immunized with B16GME7. These results suggest that allogeneic tumor cells transduced with GM-CSF and the tumor antigen, HPV-16 E7, cannot only generate an E7-specific cytotoxic T lymphocytes response in vitro, but can also elicit a potent antitumor immune response against an E7 expressing tumor in vivo.

Adjuvant therapy of stage III and IV malignant melanoma using granulocyte-macrophage colony-stimulating factor

PURPOSE

To evaluate granulocyte-macrophage colony-stimulating factor (GM-CSF) as surgical adjuvant therapy in patients with malignant melanoma who are at high risk of recurrence.

PATIENTS AND METHODS

Forty-eight assessable patients with stage III or IV melanoma were treated in a phase II trial with long-term, chronic, intermittent GM-CSF after surgical resection of disease. Patients with stage III disease were required to have more than four positive nodes or a more than 3-cm mass. All patients were rendered clinically disease-free by surgery before enrollment. The GM-CSF was administered subcutaneously in 28-day cycles, such that a dose of 125 microg/m(2) was delivered daily for 14 days followed by 14 days of rest. Treatment cycles continued for 1 year or until disease recurrence. Patients were evaluated for toxicity and disease-free and overall survival.

RESULTS

Overall and disease-free survival were significantly prolonged in patients who received GM-CSF compared with matched historical controls. The median survival duration was 37.5 months in the study patients versus 12.2 months in the matched controls (P <.001). GM-CSF was well tolerated; only one subject discontinued drug due to an adverse event (grade 2 injection site reaction).

CONCLUSION

GM-CSF may provide an antitumor effect that prolongs survival and disease-free survival in patients with stage III and IV melanoma who are clinically disease-free. These results support institution of a prospective, randomized clinical trial to definitively determine the value of surgical adjuvant therapy with GM-CSF in such patients.

Newer strategies for effective evaluation of primary melanoma and treatment of stage III and IV disease

Our objective in this article is to update dermatologists on the clinical management of malignant melanoma, including the role of sentinel node biopsy and options for the treatment of stage III and stage IV disease. The role of the dermatologist throughout the continuum of care is emphasized, and the essential partnership with medical oncology in recognizing promising new options for patients with advanced disease is examined.

Immunological effects of BCG as an adjuvant in autologous tumor vaccines

The role of Bacillus Colmette-Guérin (BCG) as an adjuvant in autologous tumor vaccines was examined. In nine patients with renal cell cancer, irradiated tumor cells alone (wild-type, WT) or with BCG were inoculated intradermally into contralateral thighs. Seven to 10 days later, the draining vaccine-primed lymph nodes (WT-VPLN and BCG-VPLN) were excised. BCG increased the number of harvested VPLN cells by 10-fold (mean +/- SE = 61.8 +/- 20.6/x10(-7)/patient). BCG-VPLN had significantly greater percentages of CD3(+) and CD4(+) T cells compared to WT-VPLN. Both groups of VPLN cells were activated in vitro with anti-CD3 or anti-CD3/CD28 mAbs followed by expansion in IL-2. Anti-CD3/CD28 activation resulted in greater expansion of CD4(+) T cells compared to anti-CD3. After activation, VPLN cells were stimulated with irradiated autologous tumor targets and cytokines (IFN-gamma, GM-CSF, IL-10) released into the supernatants were measured 24 h later. Anti-CD3/CD28-activated BCG-VPLN cells were found to have a greater release of IFN-gamma compared with that of WT-VPLN cells, which was not observed significantly with IL-10 or GM-CSF. BCG resulted in increased VPLN cell yield as well as enhanced type 1 (IFN-gamma release) immune responses of VPLN cells to autologous tumor without upregulating type 2 (IL-10 release) responses. Anti-CD3/CD28 was superior to anti-CD3 activation in this cellular response.

Adjuvant active specific immunotherapy for stage II and III colon cancer with an autologous tumor cell vaccine: Eastern Cooperative Oncology Group Study E5283

PURPOSE

A randomized phase III clinical trial of adjuvant active specific immunotherapy (ASI) with an autologous tumor cell-bacillus Calmette-Guérin (BCG) vaccine was conducted to determine whether surgical resection plus ASI was more beneficial than resection alone in stage II and III colon cancer patients.

PATIENTS AND METHODS

Patients (n = 412) with colon cancer (297 with stage II disease, 115 with stage III disease) were randomly allocated to an observation arm or to a treatment arm in which they received three weekly intradermal vaccine injections of 10(7) irradiated autologous tumor cells beginning approximately 4 weeks after surgery. The first two weekly injections also contained 10(7) BCG organisms. Patients were observed for determination of time to recurrence and disease-free and overall survival.

RESULTS

This was a negative study in that after a 7.6-year median follow-up period, there were no statistically significant differences in clinical outcomes between the treatment arms. However, there were disease-free survival (P =.078) and overall survival (P =.12) trends in favor of ASI when treatment compliance was evaluated, ie, patients who received the intended treatment had a delayed cutaneous hypersensitivity (DCH) response to the third vaccination (induration >/=5 mm). Also, the magnitude of the DCH response correlated with improved prognosis. The 5-year survival proportion was 84.6% for those with indurations greater than 10 mm, compared with 45.0% for those with indurations less than 5 mm.

CONCLUSIONS

When all randomized patients were evaluated, no significant clinical benefit was seen with ASI in surgically resected colon cancer patients with stage II or III colon cancer. However, there was an indication that treatment compliance with effective immunization results in disease-free and overall survival benefits.

Vaccination of melanoma patients with interleukin 4 gene-transduced allogeneic melanoma cells

A human melanoma line genetically modified to release interleukin 4 (IL-4) was utilized to immunize advanced melanoma patients in order to elicit or increase a specific anti-melanoma immune response, which may affect distant lesions. Twelve metastatic melanoma patients were injected subcutaneously at least three times with 5 x 10(7) IL-4 gene-transduced and irradiated allogeneic melanoma cells per dose. Both systemic and local toxicities were mild, consisting of transient fever and erythema, swelling, and induration at the vaccination site. Two mixed but not complete or partial clinical responses were recorded. To assess the immune response of vaccinated patients, both serological and cell-mediated activities were evaluated. Antibodies to alloantigens could be detected in 2 of 11 patients tested. Mixed tumor-lymphocyte cultures were performed, utilizing autologous and allogeneic HLA-A2-matched melanoma lines as simulators and targets. A significant increase in IFN-gamma release was detected in 7 of 11 cases when postvaccination lymphocytes were stimulated by the untransduced allomelanoma cells. However, induction of a specific recognition of autologous melanoma cells by PBLs was obtained after vaccination in only one of six cases studied. This response involved the melanoma peptide Melan-A/MART-1(27-35) that was recognized in an HLA-A2-restricted fashion. These results indicate that vaccination with allogeneic melanoma cells releasing IL-4 locally can expand a T cell response against antigen(s) of autologous, untransduced tumor, although in a minority of patients.

Protective immunization against melanoma by gp100 DNA-HVJ-liposome vaccine

DNA-based vaccine immunization effectively induces both humoral and cell-mediated immunity to antigens and can confer protection against numerous infectious diseases as well as some cancers. Human and mouse melanomas consistently express the tumor-associated antigen interacted with the melanogenesis pathway. Gp100 is immunogenic and has been shown to induce both antibody and cytotoxic T cell (CTL) responses in humans. To explore the potential use of DNA immunization to induce melanoma-specific immune responses, we assessed HVJ-AVE liposome incorporated with plasmid DNA encoding human gp100. The gp100 DNA vaccine was used in a mouse melanoma model to assess immunity against the B16 melanoma of C57BL/6 mice. Intramuscular injection of the DNA-HVJ-AVE liposomes induced both anti-gp100 antibody and CTL responses. Gp100 DNA-HVJ-AVE liposome immunization significantly delayed tumor development in mice challenged with B16 melanoma cells. Mice immunized with gp100 DNA-HVJ-AVE liposomes survived longer compared with control mice immunized with HVJ-AVE liposome alone. These results indicate that immunization with human gp100 DNA by HVJ-AVE liposomes can induce protective immunity against melanoma in this pre-clinical mouse model. This strategy may provide an effective approach for vaccine therapy with tumor-associated antigens against human melanoma.

Long-term survival after complete resection of melanoma metastatic to the adrenal gland

BACKGROUND

Survival of patients with American Joint Committee on Cancer stage IV melanoma is generally poor, although there are occasional long-term survivors who have undergone surgical resection of a limited number of metastases. In the study, we examined the outcome of patients with adrenal gland metastases.

METHODS

Eighty-three patients with adrenal metastases were identified from our computerized melanoma database of 8250 patients. Univariate and multivariate analyses for overall survival differences were performed by using proportional hazards modeling.

RESULTS

Median survival for the 83 patients was 9.3 months (1-67 months). Of the 27 patients who underwent surgical exploration, 18 (66%) were rendered clinically free of disease by adrenalectomy alone (12 cases) or by adrenalectomy and resection of additional disease (6 cases). Nine patients underwent palliative adrenal resection. Median survival was 25.7 months after complete resection compared with 9.2 months after palliative resection (P = .02).

CONCLUSIONS

Patients with adrenal metastases from melanoma, either isolated or with a limited number of additional metastases, may benefit from surgical resection if all visible disease can be removed. Patients with unresectable extra-adrenal disease achieve no survival benefit from adrenalectomy.

Advantages of concurrent biochemotherapy modified by decrescendo interleukin-2, granulocyte colony-stimulating factor, and tamoxifen for patients with metastatic melanoma

PURPOSE

Concurrent biochemotherapy results in high response rates but also significant toxicity in patients with metastatic melanoma. We attempted to improve its efficacy and decrease its toxicity by using decrescendo dosing of interleukin-2 (IL-2), posttreatment granulocyte colony-stimulating factor (G-CSF), and low-dose tamoxifen.

PATIENTS AND METHODS

Forty-five patients with poor prognosis metastatic melanoma were treated at a community hospital inpatient oncology unit affiliated with the John Wayne Cancer Institute (Santa Monica, CA) between July 1995 and September 1997. A 5-day modified concurrent biochemotherapy regimen of dacarbazine, vinblastine, cisplatin, decrescendo IL-2, interferon alfa-2b, and tamoxifen was repeated at 21-day intervals. G-CSF was administered beginning on day 6 for 7 to 10 days.

RESULTS

The overall response rate was 57% (95% confidence interval, 42% to 72%), the complete response rate was 23%, and the partial response rate was 34%. Complete remissions were achieved in an additional 11% of patients by surgical resection of residual disease after biochemotherapy. The median time to progression was 6.3 months and the median duration of survival was 11.4 months. At a maximum follow-up of 36 months (range, 10 to 36 months), 32% of patients are alive and 14% remain free of disease. Decrescendo IL-2 dosing and administration of G-CSF seemed to reduce toxicity, length of hospital stay, and readmission rates. No patient required intensive care unit monitoring, and there were no treatment-related deaths.

CONCLUSION

The data from this study indicate that the modified concurrent biochemotherapy regimen reduces the toxicity of concurrent biochemotherapy with no apparent decrease in response rate in patients with poor prognosis metastatic melanoma.

Anti-tumour activity against B16-F10 melanoma with a GM-CSF secreting allogeneic tumour cell vaccine

Genetic modification of tumour cells with the GM-CSF encoding gene renders these cells more potent, as autologous tumour cell vaccine, than their wild-type counterparts. However, autologous vaccines are impractical for wide-scale clinical use and we have therefore investigated the efficacy of the GM-CSF genetic modification approach with an allogeneic whole cell tumour vaccine. In this report, we show that the allogeneic K1735-M2 (H-2k) melanoma cell vaccine induces a specific protective anti-tumour response against the syngeneic B16-F10 (H-2b) melanoma tumour in C57BL/6J mice. In vitro T cell work demonstrated that vaccination of animals with the allogeneic cell vaccine generated cytotoxic T cells specific for the autologous tumour. In vivo T cell subset depletion experiments also illustrated that this anti-tumour effect was mediated by both CD4+ve and CD8+ve T cells, suggesting that the allogeneic vaccine may operate through the 'cross-priming' phenomenon whereby tumour antigens are processed and presented to T cells by the host's own antigen presenting cells (APC). Thus, we transduced K1735-M2 cells with a GM-CSF expressing retroviral vector and showed anti-tumour activity of the GM-CSF secreting K1735-M2 cells as a therapeutic vaccine against the syngeneic B16-F10 tumour. Our data imply that GM-CSF genetically modified allogeneic whole cell tumour vaccines could be successful in the clinic. In addition, more potent combination gene therapy strategies could be tested using this therapeutic allogeneic vaccine model.

Metastasectomy for recurrent stage IV melanoma

BACKGROUND AND OBJECTIVES

Many patients undergoing complete surgical resection of distant metastatic melanoma (American Joint Committee on Cancer [AJCC] stage IV) develop recurrent disease. We examined whether a second metastasectomy could prolong the survival of patients with recurrent stage IV melanoma.

DESIGN AND PATIENTS

Retrospective review of our 8,750-patient melanoma database identified 211 patients who were rendered clinically free of disease by surgical resection of stage IV metastases during the 24-year study period (January 1971 through December 1995). Our study population comprised the 131 patients who developed recurrent stage IV disease and were followed for at least 24 months or until death.

RESULTS

The median disease-free interval prior to recurrent stage IV disease was 8 months (range 0.6-91.8 months). There were 131 tumor-involved anatomic sites; the median number was one (range 1-3). Of these sites, 71 (54.2%) were soft tissue, 35 (26.7%) were pulmonary, 28 (21.4%) were gastrointestinal, 23 (17.6%) were cerebral, 13 (9.9%) were skeletal, and 2 (1.5%) were gynecologic. Median survival following treatment for recurrent stage IV melanoma was 18.2 months after complete metastasectomy, compared with 12.5 months or 5.9 months after a palliative surgical procedure or nonsurgical management, respectively. The 5-year survival rate was 20.0% (8/40) for patients in the complete surgical metastasectomy group, compared with 7.0% (3/43) and 2.1% (1/48) for those in the palliative surgical and nonsurgical groups, respectively. By multivariate analysis, the two most important prognostic factors for survival following diagnosis of recurrent stage IV melanoma were a prolonged disease-free interval to recurrence (P = 0.0001) and complete surgical metastasectomy of the recurrence (P = 0.0001).

CONCLUSIONS

Metastasectomy can prolong the survival of patients with recurrent stage IV melanoma if all clinically evident tumor can be resected.

A Model for CD8+ CTL Tumor Immunosurveillance and Regulation of Tumor Escape by CD4 T Cells Through an Effect on Quality of CTL

Understanding immune mechanisms influencing cancer regression, recurrence, and metastasis may be critical to developing effective immunotherapy. Using a tumor expressing HIV gp160 as a model viral tumor Ag, we found a growth-regression-recurrence pattern, and used this to investigate mechanisms of immunosurveillance. Regression was dependent on CD8 T cells, and recurrent tumors were resistant to CTL, had substantially reduced expression of epitope mRNA, but retained the gp160 gene, MHC, and processing apparatus. Increasing CTL numbers by advance priming with vaccinia virus expressing gp160 prevented only the initial tumor growth but not the later appearance of escape variants. Unexpectedly, CD4 cell depletion protected mice from tumor recurrence, whereas IL-4 knockout mice, deficient in Th2 cells, did not show this protection, and IFN-γ knockout mice were more susceptible. Purified CD8 T cells from CD4-depleted mice following tumor regression had more IFN-γ mRNA and lysed tumor cells without stimulation ex vivo, in contrast to CD4-intact mice. Thus, the quality as well as quantity of CD8+ CTL determines the completeness of immunosurveillance and is controlled by CD4 T cells but not solely Th2 cytokines. This model of immunosurveillance may indicate ways to enhance the efficacy of surveillance and improve immunotherapy.

Gene therapy with autologous, interleukin 2-secreting tumor cells in patients with malignant melanoma

We vaccinated metastatic melanoma patients with irradiated, autologous melanoma cells genetically engineered to secrete interleukin 2 (IL-2) to investigate whether an anti-tumor immune response would be induced. Melanoma cell cultures were established from surgical specimens and were engineered to secrete IL-2 by infection with recombinant retrovirus. Twelve patients were vaccinated subcutaneously one, two, or three times with approximately 10(7) irradiated, autologous, IL-2-secreting tumor cells. Treatment was well tolerated, with local reactions at 11 of 24 injection sites and minor systemic symptoms of fever and headache after 6 injections. One patient developed anti-tumor DTH after the first vaccination and showed an increased response after the second vaccination. Anti-autologous tumor CTLs could be detected prevaccination in the peripheral blood of seven patients and their activity increased after vaccination in four patients. No UICC-defined clinical responses were seen, but three patients had stable disease for 7-15 months, one of whom has not yet progressed (15+ months). Thus, patient vaccination with autologous, genetically engineered tumor cells is feasible and safe. Anti-tumor DTH and CTLs can be induced in some patients with such a vaccine.

Cancer vaccines with emphasis on a viral oncolysate melanoma vaccine

Biotherapy of malignant diseases has become the fourth treatment modality besides surgery, chemo- and radiotherapy. Whole cell melanoma vaccines with or without BCG and other adjuvants, purified ganglioside and shed antigens, recombinant viruses carrying tumor antigens, dendritic cells pulsed with antigenic peptides etc. are in clinical trials. Efficacious viral oncolysate vaccines induce the host to mount tumor-specific cytotoxic T-cell response and prevention of relapses is supported by clinical trials. The use of "polyvalent" whole cell vaccines vs. purified or genetically engineered single antigen vaccines is justified as i. only very few single tumor antigens are present in all tumors of a given histological type; and ii. antigen modulation occurs in tumors rendering them resistant to immune attack generated by vaccine against a single antigen. Thus polyvalent vaccines immunize against several antigens vs. against a selected antigen.

Cytotoxic T lymphocyte response against non-immunoselected tumor antigens predicts the outcome of gene therapy with IL-12-transduced tumor cell vaccine

The colon adenocarcinoma C26, carrying two endogenous tumor-associated antigens (TAA) recognized by CTL, has been transduced with the gene coding for the human folate receptor alpha (FR alpha) as an additional antigen in order to study the efficacy of vaccination against a tumor expressing multiple antigens. A dicistronic vector was used to transduce the IL-12 genes to create C26/IL-12/FR alpha that has been used as a cellular vaccine to treat mice bearing lung metastases of C26/FR alpha. After vaccination mice were partially splenectomized and splenic lymphocytes frozen and used retrospectively to study in vitro CD8 T cell response related to the treatment outcome. Vaccination cured 50% of mice and the effect was CD8 T cell dependent. Mice either cured (responders) or not cured (nonresponders) by vaccination developed tumor-specific CTL. However, analysis of CTL specificity and pCTL frequencies revealed that responders had a predominant CTL activity against endogenous C26-related tumor antigens, whereas nonresponders had CTL that recognized preferentially the FR alpha antigen. CD8 from responder mice were characterized to release high levels of granulocyte-macrophage (GM)-CSF upon antigen stimulation. Tumors obtained from mice that died despite vaccination lost expression of the FR alpha transgene but maintained expression of endogenous C26 antigens. Immunoselection against FR alpha antigen was not observed in tumors from non-vaccinated controls and from CD8-depleted vaccinated mice. Down-regulation of FR alpha antigen expression was due, at least in part, to methylation of retroviral vector long terminal repeat promoter since FR alpha expression was partially restored, ex vivo, by treatment with 5-aza-2'-deoxy-cytidine (aza). These results indicate that CD8 T cell-mediated immunoselection and production of GM-CSF are determining factors for the efficacy of tumor vaccines.

Human Glioma-Induced Immunosuppression Involves Soluble Factor(s) That Alters Monocyte Cytokine Profile and Surface Markers

Patients with gliomas exhibit deficient in vitro and in vivo T cell immune activity, and human glioblastoma culture supernatants (GCS) inhibit in vitro T lymphocyte responses. Because APC are essential for initiating and regulating T cell responses, we investigated whether GCS would affect cytokines produced by monocytes and T cells from healthy donors of PBMC. Incubation of PBMC with GCS decreased production of IL-12, IFN-γ, and TNF-α, and increased production of IL-6 and IL-10. The GCS-induced changes in IL-12 and IL-10 occurred in monocytes, and involved changes in IL-12 p40 and IL-10 mRNA expression. Incubation with GCS also resulted in reduced expression of MHC class II and of CD80/86 costimulatory molecules on monocytes. The immunosuppressive effects were not the result of IL-6 or TGF-β1 that was detected in GCS. However, it was due to a factor(s) that is resistant to pH extremes, differentially susceptible to temperature, susceptible to trypsin, and has a minimum molecular mass of 40 kDa. Our findings show that glioblastoma-generated factors that are known to suppress T cell responses alter the cytokine profiles of monocytic APC that, in turn, inhibit T cell function. This model indicates that monocytes can serve as an intermediate between tumor-generated immune-suppressive factors and the T cell responses that are suppressed in gliomas.

Immunotherapy of metastatic malignant melanoma by a vaccine consisting of autologous interleukin 2-transfected cancer cells: outcome of a phase I study

We performed a phase I trial to evaluate the safety and tolerability of repeated skin injections of IL-2-transfected autologous melanoma cells into patients with advanced disease. Cell suspensions, propagated from excised metastases, were IL-2 gene transfected by adenovirus-enhanced transferrinfection and X-irradiated prior to injection. Vaccine production was successful in 54% of the patients. Fifteen patients (37%) received two to eight skin vaccinations of either 3 x 10(6) (intradermal) or 1 x 10(7) (half intradermal, half subcutaneous) transfected melanoma cells per vaccination (secreting 140-17,060 biological response modifier program units of IL-2/10(6) cells/24 hr). Analyses of safety and efficacy were carried out in 15 and 14 patients, respectively. Overall, the vaccine was well tolerated. All patients displayed modest local reactions (erythema, induration, and pruritus) and some experienced flu-like symptoms. Apart from newly appearing (4 of 14) and increasing (5 of 14) anti-adenovirus and newly detectable anti-nuclear antibody titers (1 of 15), recipients developed de novo or exhibited increased melanoma cell-specific delayed-type hypersensitivity (DTH) reactions (8 of 15) and vitiligo (3 of 15) and showed signs of tumor regression (3 of 15). This supports the idea of a vaccine-induced or -amplified anti-cancer immune response. None of the patients exhibited complete or partial regressions, but five of them experienced periods of disease stabilization. Three of these individuals received more than the four planned vaccinations and their mean survival time was 15.7 +/- 3.5 months as compared to 7.8 +/- 4.6 months for the entire patient cohort. These data indicate that IL-2-producing, autologous cancer cells can be safely administered to stage IV melanoma patients and could conceivably be of benefit to patients with less advanced disease.

Clinical implications of the new biology in the development of melanoma vaccines

There has been a resurgence in clinical research of vaccine therapies, particularly for the treatment of melanoma. The renewed interest in this field is attributable to an increased understanding regarding the immune response to tumors and the immunobiology of melanoma. Molecular biology techniques have enabled investigators to develop genetically engineered tumor vaccines that are intended to favor the type 1 immune response over the type 2 response. Melanoma-associated antigens have been characterized at the molecular level and are currently being investigated in clinical trials. Dendritic cell biology has also provided a potent method to present antigens to the host for immunization. Lastly, vaccines are being explored as a method to generate immune T-cells for adoptive immunotherapy. These new areas of clinical investigation will be reviewed in the context of the historical developments that have laid the foundations of this field.

Prospects for the therapeutic use of anticancer vaccines

Although a century has passed since initial attempts were made to stimulate the immune system to destroy tumour, the immunotherapy of cancer is still in the early stages. Historically, a variety of specific and nonspecific immunostimulatory strategies have been administered with only modest clinical success. However, recent advances in tumour immunology, most notably the identification of genes encoding for cancer regression antigens, have paved the way for the development of a variety of novel and specific vaccine approaches. These include vaccines based on tumour cells, carbohydrates, peptides and heat-shock proteins, DNA-based vaccination, and the use of recombinant bacteria and viruses to deliver antigens or the DNA coding for them. While several of these approaches have yielded exciting clinical results, a number of immunological and host obstacles to the successful application of cancer vaccines remain. Further research is needed on the optimum choice of antigen, delivery vector, adjuvant and administration regimen.

IgM anti-ganglioside antibodies induced by melanoma cell vaccine correlate with survival of melanoma patients

Melanoma cells express ganglioside antigens GM3, GD3, GM2, and GD2 on their surface. This study examined whether immunization with a melanoma cell vaccine induced anti-ganglioside antibody responses in melanoma patients and whether these responses were correlated with survival. Sixty-six patients who had received melanoma cell vaccine immunotherapy after surgical removal of regional metastatic melanoma were identified. Cryopreserved serum samples from these patients were used in an enzyme-linked immunsorbent assay to determine the IgM antibody levels to GM2, GD2, GM3, and GD3 prior to melanoma cell vaccine treatment and 4 wk after the first melanoma cell vaccine immunization. All antibody levels significantly increased by week 4 (p < 0.001 for all four antibodies) and all increases were significantly associated with survival (anti-GD2, p < 0.001; anti-GM2, p = 0.001; anti-GD3, p < 0.001; anti-GM3, p < 0.001). Anti-tumor activity of these antibodies was proved using five representative antibody-positive sera in a complement-dependent cytotoxicity assay with cultured melanoma cell lines. These studies suggest that GM2, GD2, GM2, and GD3 expressed by melanoma cells can induce specific IgM antibodies and that high levels of these antibodies might have a beneficial impact on survival.

Cancer vaccines: novel approaches and new promise

Cancer vaccines are a promising tool in the hands of the clinical oncologist. We have summarized the most recent findings and achievements in this exciting field. Tumor-associated antigens, as a basis for the new cancer vaccines, are reviewed. We emphasize novel approaches for the design of safe and more effective vaccines for cancer. We also discuss the possible clinical applications and the future prospects for vaccine development.

Anti-tyrosinase-related protein-2 immune response in vitiligo patients and melanoma patients receiving active-specific immunotherapy

Several melanosome glycoproteins have been shown to be antigenic in humans. Correlation of antigen-specific immune responses in patients with the autoimmune disease vitiligo, therapy-induced hypopigmentation, and cutaneous melanoma has not been well studied. We examined antibody responses to a melanocyte autoantigen, tyrosinase-related protein-2 (TRP-2), as it is highly expressed in cutaneous melanoma and melanocytes. TRP-2 recombinant protein was synthesized for western blot and affinity anti-TRP-2 enzyme-linked immunosorbent assay. We demonstrated that patients with malignant melanoma, vitiligo, and active-specific immunotherapy-induced depigmentation had significant anti-TRP-2 IgG titers. The highest level of anti-TRP-2 IgG response was found in vitiligo patients. Induction and enhancement of anti-TRP-2 IgG responses were observed in melanoma patients treated with a polyvalent melanoma cell vaccine containing TRP-2. Active-specific immunotherapy could induce and/or augment the TRP-2 IgG antibody titers. Melanoma patients who developed hypopigmentation and had improved survival after polyvalent melanoma cell vaccine had significantly augmented anti-TRP-2 antibody responses compared with patients with poor prognosis. This study demonstrates that TRP-2 autoantigen is immunogenic in humans. TRP-2 antibody responses provide a linkage between autoimmune responses by vitiligo patients and melanoma patients responding to immunotherapy who have induced hypopigmentation.

Molecular biology of human melanoma development and progression

In the United States, Australia, Northern Europe, and Canada, malignant melanoma is increasing at a faster rate than any other cancer, with the exception of lung cancer in women. Major advances have been made in the molecular biology and immunology of melanoma. These advances in basic science have led to more rational approaches to specifically targeting melanoma cells, with promising results in the clinic. An increased understanding of how melanoma spreads has led to more selective, less invasive surgical procedures that do not compromise patient health. Combinations of chemotherapy and immunotherapy are now available for patients with advanced melanoma that affect both the length and quality of the patients' lives. This review of the molecular biology of melanoma development and progression discusses the disease's etiology, molecular genetics, cell-surface antigens, experimental models, biological markers, and new forms of treatment. As we continue to learn more about malignant melanoma, we will be able to devise more specific and effective treatments that will give patients with this potentially deadly disease longer and more productive lives.

Vaccination with irradiated autologous melanoma cells engineered to secrete human granulocyte-macrophage colony-stimulating factor generates potent antitumor immunity in patients with metastatic melanoma

We conducted a Phase I clinical trial investigating the biologic activity of vaccination with irradiated autologous melanoma cells engineered to secrete human granulocyte-macrophage colony-stimulating factor in patients with metastatic melanoma. Immunization sites were intensely infiltrated with T lymphocytes, dendritic cells, macrophages, and eosinophils in all 21 evaluable patients. Although metastatic lesions resected before vaccination were minimally infiltrated with cells of the immune system in all patients, metastatic lesions resected after vaccination were densely infiltrated with T lymphocytes and plasma cells and showed extensive tumor destruction (at least 80%), fibrosis, and edema in 11 of 16 patients examined. Antimelanoma cytotoxic T cell and antibody responses were associated with tumor destruction. These results demonstrate that vaccination with irradiated autologous melanoma cells engineered to secrete granulocyte-macrophage colony-stimulating factor stimulates potent antitumor immunity in humans with metastatic melanoma.

Antibody responses to melanoma/melanocyte autoantigens in melanoma patients

Melanogenesis-related proteins play important roles in melanin synthesis and antigenicity of melanomas. Identification of highly expressed melanoma-associated antigens (MAA) that are immunogenic in humans will provide potential targets for cancer vaccines. Melanogenesis-related proteins have been shown to be MAA. Autoantibody responses to these MAA have been shown to react with melanoma cells and melanocytes, and suggested to play a role in controlling melanoma progression. To assess antibody responses to potential melanoma/melanocyte autoantigens, the open-reading frame sequences of tyrosinase, tyrosinase-related protein (TRP)-1, TRP-2, and melanoma-associated glycoprotein antigen family (gp100/pmel17) genes were cloned and expressed as recombinant proteins in E. coli. Purified recombinant antigens were employed to detect antibodies in sera of melanoma patients and normal healthy donors. By affinity enzyme-linked immunosorbent assay and western blotting, all recombinant antigens were shown to be antigenic. The main subclass of antibody response to these antigens was IgG. Most importantly this study demonstrated anti-TRP-2 and anti-gp100/pmel17 IgG responses in melanoma patients. Only one of 23 normal donors had an antibody response to the antigens tested. MAA-specific IgG antibodies in sera were assessed in melanoma patients (n = 23) pre- and post-polyvalent melanoma cell vaccine treatment. Polyvalent melanoma cell vaccine treatment enhanced anti-MAA antibody responses; however, only anti-TRP-2 and anti-gp100/pmel17 antibody response was enhanced. These studies suggest that four melanogenesis-related proteins are autoimmunogenic and can be used as potential targets for active-specific immunotherapy.

Enhancement of complement-dependent cytotoxicity by polyvalent melanoma cell vaccine (CancerVax): correlation with survival

BACKGROUND

Case control studies have demonstrated that administration of CancerVax, a polyvalent melanoma cell vaccine (PMCV), after complete resection of melanoma metastases produces a significant improvement in disease-free survival (DFS). Because PMCV has no direct cytotoxic effect on melanoma cells, the authors hypothesized that it prolongs survival by enhancing antibody-mediated antimelanoma cytotoxicity.

METHODS

One hundred melanoma patients participating in a trial of PMCV adjuvant therapy following complete resection of regional node metastases were randomly selected for study. Serum samples obtained immediately before (T0) and 4, 8, 12, and 16 weeks after initiation of PMCV adjuvant therapy were adsorbed with L-14 lymphoblastoid cells and then tested for in vitro complement-dependent cytotoxicity (CDC) against M-14 cells, a melanoma cell line not used in PMCV. CDC was expressed as percentage of total cells (n = 10,000) killed. Survival curves were estimated by the Kaplan-Meier method. Statistical analysis was performed by the signed rank sum test, Spearman test, log-rank test, and Cox proportional hazard regression.

RESULTS

Median CDC at T0 was 4.5% (range, 0% to 40%). Within 16 weeks after initiation of PMCV therapy, CDC had increased in 82 (82%) patients. The median increase of 7.5% (range, -9% to 39%) represented a highly significant change (signed rank sum test; P = .0001). At a median follow-up of 29 months (range, 6 to 92 months), the maximum increase in CDC (deltaCDC) as a continuous variable was significantly correlated with DFS (P = .0001). Median survival and 5-year DFS were more than 54 months and less than 54%, respectively, for patients with deltaCDC > or =10% (n = 44) but only 7 months and 14%, respectively, for those with deltaCDC <10% (n = 56; P = .0001). Multivariate analysis confirmed deltaCDC as the most significant independent variable associated with DFS following initiation of PMCV therapy (P = .0001).

CONCLUSION

PMCV therapy greatly enhances serum CDC against melanoma cells. This enhancement is directly correlated with DFS following initiation of vaccine therapy.

Immunotherapy and experimental approaches for metastatic melanoma

This article reviews the clinical investigations involving recombinant cytokines (either alone or in combination with adoptive immunotherapy, toxicity reduction agents, or cytotoxic chemotherapy), vaccines, monoclonal antibodies or antibody conjugates, and gene therapy. These various approaches are reviewed for their current and potential roles in curing metastatic melanoma.

Positron emission tomography plus serum TA90 immune complex assay for detection of occult metastatic melanoma

BACKGROUND

Whole-body positron emission tomography (PET) using 18F-fluorodeoxyglucose is very sensitive for detection of metastatic melanoma. We previously reported the accuracy of a serum TA90 enzyme-linked immunosorbent assay (ELISA) in predicting the recurrence of early-stage melanoma. This serum ELISA measures a circulating immune complex composed of TA90 a tumor-associated 90-kD glycoprotein antigen, and its IgG antibody. We hypothesized that using PET examination in conjunction with our serum TA90 ELISA would increase the detection of occult melanoma lesions.

STUDY DESIGN

From November 1, 1993 to December 31, 1995, 87 patients underwent PET examination followed within 6 weeks by serum TA90 ELISA. All patients had undergone complete resection of local, regional, or distant metastatic melanoma and had no clinical evidence of disease at the time of PET examination. Each patient had complete followup for 12 months after PET examination. The clinical course was determined by chart review of clinical and radiographic findings.

RESULTS

Of the 25 patients who experienced recurrence of disease within 6 months of followup, 22 (88%) had a positive result on one or both tests. Of the 52 patients with a negative result on both tests, 49 (94%) remained disease-free at 6 months of followup. Of the 14 patients who developed distant metastases within 6 months after PET examination, 13 (93%) had a positive PET examination and/or a positive TA90 ELISA.

CONCLUSIONS

The TA90 ELISA correlated well with PET examination for detection of metastatic melanoma. The high sensitivity of PET examination plus TA90 ELISA suggests that this combination may have a role in the surveillance of patients at high risk of developing metastatic melanoma.

Future perspectives in specific immunotherapy of melanoma

With the discovery of T-cell recognised tumour-associated antigens (TAAs), interest in specific immunotherapy for treatment of malignancies has increased substantially. The majority of studies investigating TAAs have focused on melanoma-associated antigens because of evidence that the immune system influences the pathogenesis of melanoma. This paper reviews the different types of melanoma antigens, their in vitro and in vivo immunogenicity and clinical data regarding the use of specific immunotherapy in patients with stage I-IV melanoma. Results of clinical studies are highly variable but encourage further research in these patients. Developing and perfecting laboratory and clinical correlates of response to these specific immunotherapies are vital to determining their role in clinical practice.