Fully synthetic carbohydrate-based vaccines in biochemically relapsed prostate cancer: clinical trial results with alpha-N-acetylgalactosamine-O-serine/threonine conjugate vaccine.

PURPOSE: We report the synthesis of a mucin-related O-linked glycopeptide, alpha-N-acetylgalactosamine-O-serine/threonine (Tn), which is highly simplistic in its structure and can induce a relevant humoral response when given in a trimer or clustered (c) formation. We tested for an antitumor effect, in the form of a change in the posttreatment versus pretreatment prostate-specific antigen (PSA) slopes, that might serve as a surrogate for effectiveness of vaccines in delaying the time to radiographic progression. METHODS: We compared the antibody response to immunization with two conjugates, Tn(c)-keyhole limpet hemocyanin (KLH) and Tn(c)-palmitic acid (PAM) with the saponin immunologic adjuvant QS21, in a phase I clinical trial in patients with biochemically relapsed prostate cancer. Patients received Tn(c)-KLH vaccine containing either 3, 7, or 15 microg of Tn(c) per vaccination. Ten patients received 100 microg of Tn(c)-PAM. QS21 was included in all vaccines. Five vaccinations were administered subcutaneously during 26 weeks with an additional booster vaccine at week 50. RESULTS: Tn(c), when given with the carrier molecule KLH and QS21, stimulated the production of high-titer immunoglobulin M (IgM) and IgG antibodies. Inferior antibody responses were seen with T(c)-PAM. There was no evidence of enhanced immunogenicity with increasing doses of vaccine. An antitumor effect in the form of a decline in posttreatment versus pretreatment PSA slopes was also observed. CONCLUSION: A safe synthetic conjugate vaccine in a trimer formation was developed that can break immunologic tolerance by inducing specific humoral responses. It seemed to affect the biochemical progression of the disease as determined by a change in PSA log slope.     

Induction of antibodies against GM2 ganglioside by immunizing melanoma patients using GM2-keyhole limpet hemocyanin + QS21 vaccine: a dose-response study.

In a previous randomized Phase III trial (P. O. Livingston et al, J. Clin. Oncol., 12: 1036-1044, 1994), we demonstrated that immunization with GM2 and bacille Calmette-Guerin reduced the risk of relapse in stage III melanoma patients who were free of disease after surgical resection and who had no preexisting anti-GM2 antibodies. That vaccine formulation induced IgM anti-GM2 antibodies in 74% but induced IgG anti-GM2 antibodies in only 10% of the patients. To optimize the immune response against GM2, a reformulated vaccine was produced conjugating GM2 to keyhole limpet hemocyanin (KLH) and using the adjuvant QS21 (GM2-KLH/QS21). In pilot studies, 70 microg of vaccine induced IgG anti-GM2 antibodies in 76% of the patients. We wished to define the lowest vaccine dose that induced consistent, high-titer IgM and IgG antibodies against GM2. Fifty-two melanoma patients who were free of disease after resection but at high risk for relapse were immunized with GM2-KLH/QS21 vaccine at GM2 doses of 1, 3, 10, 30, or 70 ILg on weeks 1, 2, 3, 4, 12, 24, and 36. Serum collected at frequent and defined intervals was tested for anti-GM2 antibodies. Overall, 88% of the patients developed IgM anti-GM2 antibodies; 71% also developed IgG anti-GM2 antibodies. GM2-KLH doses of 3-70 microg seemed to be equivalent in terms of peak titers and induction of anti-GM2 antibodies. At the 30-microg dose level, 50% of the patients developed complement fixing anti-GM2 antibodies detectable at a serum dilution of 1:10. We conclude that the GM2-KLH/QS21 formulation is more immunogenic than our previous formulation and that 3 microg is the lowest dose that induces consistent, high-titer IgM and IgG antibodies against GM2.     

Consistent antibody response against ganglioside GD2 induced in patients with melanoma by a GD2 lactone-keyhole limpet hemocyanin conjugate vaccine plus immunological adjuvant QS-21.

PURPOSE: Melanomas, sarcomas, and neuroblastomas abundantly express the ganglioside GD2 on the cell surface where it is susceptible to immune attack by antibodies. Overexpression of GD2 on these tumors is striking, as is the frequency of clinical responses after treatment of neuroblastoma with monoclonal antibodies against GD2. In addition, preclinical models have demonstrated the ability of a GD2-keyhole limpet hemocyanin (KLH) conjugate vaccine to induce antibodies that eliminate micrometastases. However, vaccination of patients with GD2-KLH has previously failed to induce a consistent relevant antibody response. We test here whether the use of GD2 lactone-KLH can overcome the low immunogenicity of GD2-KLH. EXPERIMENTAL DESIGN: Eighteen patients with melanoma were vaccinated s.c. in the adjuvant setting on weeks 0, 1, 2, 3, 10, and 24. Groups of 6 patients were entered at three dose levels (3, 10, or 30 micro g) of GD2 lactone (GD2L) in vaccines containing GD2L-KLH plus the immunological adjuvant QS-21. Blood was drawn at regular intervals to assess the antibody response. RESULTS: The vaccine was well tolerated. The majority of patients in all three dose levels produced anti-GD2 antibodies detectable by ELISA assay. Specificity for GD2 was also confirmed by immune thin-layer chromatography. Although there was no statistical difference in terms of titers between the three groups, patients at the 30- micro g dose level had higher titers and longer lasting antibody responses overall by ELISA (median IgM/IgG peak titer 1:640/1:80) and generated the strongest cell surface reactivity by fluorescence-activated cell sorting (median IgM peak percentage positive cells/mean fluorescence intensity for pre- and postvaccination sera is 10%/63 and 70%/135). Patients vaccinated with the 30- micro g GD2 dose also had the most potent complement dependent cytotoxicity using human complement, with 5 of 6 patients showing strong cell surface reactivity by fluorescence-activated cell sorting and >30% cytotoxicity by chromium release with a serum dilution of 1/100. CONCLUSIONS: GD2L-KLH conjugate vaccine plus adjuvant QS-21 induces antibodies against GD2 that bind to the cell surface and induce complement-dependent cytotoxicity in the majority of patients with melanoma.     

Immunization of high-risk breast cancer patients with clustered sTn-KLH conjugate plus the immunologic adjuvant QS-21.

PURPOSE: To determine the clinical toxicities and antibody response against sTn and tumor cells expressing sTn following immunization of high-risk breast cancer patients with clustered sTn-KLH [sTn(c)-KLH] conjugate plus QS-21. EXPERIMENTAL DESIGN: Twenty-seven patients with no evidence of disease and with a history of either stage IV no evidence of disease, rising tumor markers, stage II (>or=4 positive axillary nodes), or stage III disease received a total of five injections each during weeks 1, 2, 3, 7, and 19. Immunizations consisted of sTn(c)-KLH conjugate containing 30, 10, 3, or 1 microg sTn(c) plus 100 microg QS-21. Induction of IgM and IgG antibodies against synthetic sTn(c) and natural sTn on ovine submaxillary mucin were measured before and after therapy. Fluorescence-activated cell sorting analyses assessed reactivity of antibodies to LSC and MCF-7 tumor cells. RESULTS: The most common toxicities were transient local skin reactions at the injection site and mild flu-like symptoms. All patients developed significant IgM and IgG antibody titers against sTn(c). Antibody titers against ovine submaxillary mucin were usually of lower titers. IgM reactivity with LSC tumor cells was observed in 21 patients and with MCF-7 cells in 13 patients. There was minimal IgG reactivity with LSC cells. CONCLUSION: Immunization with sTn(c)-KLH conjugate plus QS-21 is well tolerated and immunogenic in high-risk breast cancer patients. Future trials will incorporate sTn(c) as a component of a multiple antigen vaccine.     

Vaccination of high-risk breast cancer patients with mucin-1 (MUC1) keyhole limpet hemocyanin conjugate plus QS-21.

Our objective was to determine whether an immune response can be generated against MUC1 peptide and against tumor cell MUC1 after vaccination with MUC1-keyhole limpet hemocyanin (KLH) conjugate plus QS-21 in breast cancer patients. Nine patients with a history of breast cancer but without evidence of disease were treated with MUC1-KLH conjugate plus QS-21, containing 100 microg of MUC1 and 100 microg of QS-21. s.c. vaccinations were administered at weeks 1, 2, 3, 7, and 19. Peripheral blood was drawn at frequent intervals to assess antibody titers. Skin tests were placed at weeks 1, 3, 9, and 21 to determine delayed type hypersensitivity reactions. Common toxicities included a local skin reaction at the site of the vaccine, usually of 4-5 days' duration, and mild flu-like symptoms usually of 1-2 days' duration. High IgM and IgG antibody titers against synthetic MUC1 were detected. IgG antibody titers remain elevated from a minimum of 106-137 weeks after the first vaccination. Binding of IgM antibody to MCF-7 tumor cells was observed in seven patients, although there was minimal binding of IgG antibody. Two patients developed significant antibody titers post-high-dose chemotherapy and stem cell reinfusion. There was no evidence of T cell activation. This MUC1-KLH conjugate plus QS-21 was immunogenic and well tolerated in breast cancer patients. Additional trials are ongoing to determine the optimal MUC1 peptide for use in larger clinical trials. Further investigation of vaccine therapy in high-risk breast cancer is warranted.     

A randomised phase II study of sialyl-Tn and DETOX-B adjuvant with or without cyclophosphamide pretreatment for the active specific immunotherapy of breast cancer.

Studies in animal models of mouse mammary carcinoma have shown that ovine submaxillary mucin, which carries multiple sialyl-Tn (STn) epitopes, is effective in stimulating an immune response and inhibiting tumour growth. In similar studies using carbohydrate antigens, pretreatment with low-dose cyclophosphamide has been shown to be important in modulating the immune response to antigen possibly by inhibiting suppresser T-cell activity. In a clinical trial assessing the efficacy and toxicity of synthetic STn, patients with metastatic breast cancer were randomised to receive 100 micrograms STn linked to keyhole limpet haemocyanin (KLH) with DETOX-B adjuvant given by subcutaneous injection at weeks 0, 2, 5 and 9 with or without low-dose cyclophosphamide (CTX, 300 mg m-2) pretreatment, 3 days before the start of immunotherapy. Patients with responding or stable disease after the first four injections were eligible to receive STn-KLH at 4 week intervals. The main toxicity noted was the development of subcutaneous granulomata at injection sites. Of 23 patients randomised, 18 received four injections, 5 patients having developed progressive disease during the initial 12 week period. Two minor responses were noted in the 18 patients who received four active specific immunotherapy (ASI) injections and a further five patients had stable disease. Six patients continued ASI at 4 week intervals and a partial response was noted in a patient who had previously had stable disease. All patients developed IgG and IgM responses to sialyl-Tn and levels of IgM antibodies were significantly higher in those patients who were pretreated with CTX. Measurable tumour responses have been recorded following ASI with STn-KLH plus DETOX and the immunomodulatory properties of low-dose CTX have been confirmed.     

Immunization of ovarian cancer patients with a synthetic Lewis(y)-protein conjugate vaccine: a phase 1 trial

As the initial step in developing carbohydrate-based vaccines for the treatment of ovarian cancer patients in an adjuvant setting, 25 patients were immunized with a Lewis(y) pentasaccharide (Le(y))-keyhole limpet hemocyanin (KLH)-conjugate vaccine together with the immunological adjuvant QS-21. Four different doses of the vaccine, containing 3, 10, 30, and 60 microg of carbohydrate were administered s.c. at 0, 1, 2, 3, 7, and 19 weeks to groups of 6 patients. Sera taken from the patients at regular intervals were assayed by ELISA for reactivity with naturally occurring forms of Le(y) (Le(y)-ceramide and Le(y) mucin) and by flow cytometry and a complement-dependent cytoxicity assay for reactivity with Le(y)-expressing tumor cells. The majority of the patients (16/24) produced anti-Le(y) antibodies as assessed by ELISA, and a proportion of these had strong anti-tumor cell reactivity as assessed by flow cytometry and complement-dependent cytotoxicity. One serum, analyzed in detail, was shown to react with glycolipids but not with glycoproteins or mucins expressed by ovarian cancer cell line OVCAR-3. The vaccine was well tolerated and no gastrointestinal, hematologic, renal, or hepatic toxicity related to the vaccine was observed. On the basis of this study, Le(y)-KLH should be a suitable component for a polyvalent vaccine under consideration for the therapy of epithelial cancers.     

Induction of antibodies against GD3 ganglioside in melanoma patients by vaccination with GD3-lactone-KLH conjugate plus immunological adjuvant QS-21

The gangliosides GD3, GD2 and GM2 are expressed on the cell surface of malignant melanomas, GD3 being the most abundant. We have shown that immunization of melanoma patients with GM2 adherent to Bacillus Calmette-Guerin (GM2/BCG) induced an IgM antibody response. Vaccines containing GM2-keyhole limpet hemocyanin (KLH) conjugate and the immunological adjuvant QS-21 induced a higher titer IgM response and consistent IgG antibodies. Patients with antibodies against GM2 survived longer than patients without antibody. On the other hand, our previous trials with GD3/BCG, GD3 derivatives including GD3-lactone (GD3-L)/BCG failed to induce antibodies against GD3. In our continuing efforts to induce antibody against GD3, we have immunized groups of 6 melanoma patients with GD3-KLH or GD3-L-KLH conjugates containing 30 microg of ganglioside plus 100 microg of QS-21 at 0, 1, 2, 3, 7 and 19 weeks. Prior to vaccination, no serological reactivity against GD3 or GD3-L was detected. After immunization, IgM and IgG antibodies were detected against both GD3 and GD3-L in the GD3-L group exclusively. The GD3-L-KLH vaccine induced IgM titers against GD3-L of 1:40-1/1,280 in all patients and IgG titers of 1/160-1/1,280 in 4 patients. These antibodies also strongly cross-reacted with GD3. ELISA reactivity was confirmed by immune thin-layer chromatography on GD3 and melanoma extracts. Sera obtained from 4 of these 6 patients showed cell surface reactivity by FACS and from 2 showed strong cell surface reactivity by immune adherence (IA) assay and complement lysis against the GD3 positive cell line SK-Mel-28.     

Long-term follow-up of idiotype vaccination in human myeloma as a maintenance therapy after high-dose chemotherapy.

The aim of this work was to evaluate the long-term immunological and clinical impact of idiotype (Id) vaccination in multiple myeloma (MM) patients in first remission after high-dose chemotherapy. A total of 15 patients received a series of subcutaneous (s.c.) injections of autologous Id, conjugated to keyhole limpet hemocyanin (KLH) and in association with low doses of GM-CSF. The median duration of follow-up was 110 months from diagnosis. The vaccine induced immune responses that lasted almost 2 years after the end of treatment. Antibody responses included anti-KLH IgM and IgG (90% of patients), anti-KLH IgE (30%), anti-GM-CSF IgG (20%), anti-Id IgG (20%), and anti-Id IgE (30%). Id-specific delayed type hypersensitivity skin tests were positive in 85% of tested patients. Following vaccination, a progressive recovery of T-cell receptor (TCR) diversity was observed and the loss of oligoclonality was significantly correlated with the remission duration. Although Id/KLH conjugates did not eliminate the residual tumor burden, the median progression-free survival, and overall survival were 40 and 82 months, respectively. A retrospective case-matched analysis showed similar results in patients treated with IFN-alpha alone or in association with steroids. This vaccine formulation can overcome Id-specific immune tolerance by inducing clinical responses that are worthy of further investigation.     

Clinical development of the STn-KLH vaccine (Theratope)

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

The role of cancer vaccines following autologous stem cell rescue in breast and ovarian cancer patients: experience with the STn-KLH vaccine (Theratope)

The success of high-dose chemotherapy followed by autologous stem-cell rescue as treatment for breast and ovarian cancer is limited by a high incidence of relapse. After autologous transplantation, patients are likely to have a low tumor burden and thus would be more likely to respond immunologically to a cancer vaccine. Sialyl-Tn (STn) is a carbohydrate associated with the MUC1 mucin on breast and ovarian cancer and is an ideal candidate for vaccine immunotherapy. Sialyl-Tn-keyhole limpet hemocyanin (STn-KLH) vaccine (Theratope) incorporates a synthetic STn antigen that mimics the unique tumor-associated STn carbohydrate and is designed to stimulate tumor antigen-specific immune responses in patients with mucin-expressing tumors. Between 1995 and 2000, 70 patients (16 with stage II/III breast cancer, 17 with stage III/IV ovarian cancer, and 37 with stage IV breast cancer) were treated with 2 different formulations of STn-KLH. Toxicity, outcome, and immune response data are reported. STn-KLH was well-tolerated with minimal toxicity. The most common side effects were indurations and erythema at the sites of injections. Humoral and cellular responses were elicited in the majority of patients. Overall, these data indicate that post-autologous transplant patients are able to mount an effective immune response to vaccine immunotherapy with minimal side effects, and that vaccine immunotherapy may be a useful addition to high-dose chemotherapy regimens.     

Correlation between sialyl Tn antigen and lymphatic metastasis in patients with Borrmann type IV gastric carcinoma.

The expression of sialyl Tn (STn) antigen in 180 patients with Borrmann type IV gastric carcinomas was examined immunohistochemically. The rate of positive STn staining was 32% (57/180) for the primary tumours, and this positive staining correlated well with tumour extension, lymph node metastasis (P < 0.05) and peritoneal dissemination (P < 0.01). One-third (5/15) of patients with positive STn-staining cancer cells had a high level of serum STn. Lesions with positive STn staining were related to a lower survival rate for the patients (P < 0.05). Proliferative activity of the tumour, as measured by proliferating nuclear antigen (PCNA) labelling percentage and argyrophilic nucleolar organiser region (AgNOR) count, was significantly higher (41.5 +/- 13.0%, 3.78 +/- 0.98) in the STn-positive group than in the STn-negative group (34.2 +/- 13.2%, 3.48 +/- 0.85) (P < 0.01, P < 0.05 respectively). Estimating STn antigen may be useful for predicting the likelihood of lymph node metastasis or peritoneal dissemination and the clinical prognosis for patients with Borrmann type IV gastric carcinoma.     

Sequential immunization of melanoma patients with GD3 ganglioside vaccine and anti-idiotypic monoclonal antibody that mimics GD3 ganglioside.

GD3 ganglioside is an attractive target for immunotherapy of melanoma because it is abundantly expressed on all melanomas but not expressed on most normal tissues. Although GD3 has proven to be one of the least immunogenic gangliosides, our recent studies showed that anti-GD3 antibodies can be induced in patients immunized either with GD3-lactone-KLH (GD3-L-KLH) plus QS-21 adjuvant or with BEC2 anti-idiotypic monoclonal antibody vaccine, which mimics GD3, plus Bacillus Calmette-Guérin. We compared the immunogenicity of these two vaccines and tested whether one vaccine could prime an antibody response to the other. This is the first clinical trial immunizing patients with both antigen and anti-idiotypic monoclonal antibody vaccine. Twenty-four melanoma patients were randomized to be immunized with either BEC2 followed by GD3-L-KLH or in the opposite order. Our prior study suggested that a 25-microg dose of BEC2 was more immunogenic than our standard dose of 2.5 mg and therefore was used in this trial. Overall, 10 of 24 patients (42%) developed anti-GD3 antibodies detectable by ELISA, five in each cohort. All antibody responses were in response to the GD3-L-KLH vaccine. We found no evidence of priming by either vaccine. Antibody responses did not correlate with survival outcomes. Cellular responses were detected by enzyme-linked immunospot against BEC2, Bacillus Calmette-Guérin, and KLH, but not against GD3. We confirmed that GD3-L-KLH vaccine induces anti-GD3 antibodies, but we were unable to confirm our previous finding that a 25-microg dose of BEC2 is immunogenic. Future multivalent ganglioside vaccines should include the GD3-L-KLH vaccine.     

Sialyl Tn antigen is an independent predictor of outcome in patients with gastric cancer

The prognostic value of the immunohistochemical expression of Sialyl Tn antigen (STn) was evaluated in 242 patients with gastric carcinoma. Formalin-fixed, paraffin-embedded specimens of gastric adenocarcinomas were stained with the monoclonal antibody C1282, produced by immunization with ovine submaxillary mucin (OSM). Positive immunoreactivity for STn was observed in 149 (62%) patients. The expression of STn did not correlate with stage of disease (TNM), tumour location, presence of lymph-node or distant metastases, histological type, age or gender. STn immunoreactivity correlated strongly with overall survival in univariate analysis. The median survival in the STn-positive group was 21 months, in comparison to 38 months in the STn-negative group. The difference in survival between STn-negative and STn-positive tumours was significant in patients with stage-1 cancer, but not in patients with stage-II -III or -IV disease. STn immunoreactivity emerged as an independent prognostic factor in Cox multivariate analysis. It is concluded that the immunohistochemical expression of STn is a good marker in the prediction of survival in patients with stage-1 gastric carcinoma. © 1996 Wiley-Liss, Inc.     

Vaccination of small cell lung cancer patients with polysialic acid or N-propionylated polysialic acid conjugated to keyhole limpet hemocyanin.

PURPOSE: Long chain polysialic acid (polySA) is a side chain on embryonal neural cell adhesion molecules that, in the adult, is largely restricted to small cell lung cancer (SCLC). Long chains of polySA are also expressed on group B meningococcus. In this clinical trial, we aimed to elicit an immune response against polysialic acid to target clinically inapparent residual disease in patients with SCLC who had successfully completed initial therapy. EXPERIMENTAL DESIGN: Patients were vaccinated with either 30 micro g unmodified polySA or N-propionylated-polySA (NP-polySA), conjugated to keyhole limpet hemocyanin (KLH) and mixed with 100 micro g of immunological adjuvant QS-21 at weeks 1, 2, 3, 4, 8, and 16. RESULTS: Of the 5 evaluable patients vaccinated with unmodified polySA, only 1 mounted an IgM antibody response to polySA. On the other hand, all 6 of the patients vaccinated with NP-polySA produced IgM antibodies to NP-polySA and these cross-reacted with unmodified polySA in all but 1 case. IgG antibodies to NP-polySA were observed in 5 of the patients, but these did not cross-react with polySA. The presence of IgM antibodies reactive with SCLC cell lines was confirmed in this group by flow cytometry. Complement-dependent lysis of tumor cells could not be demonstrated. However, postimmunization sera induced significant bactericidal activity against group B meningococcus when combined with rabbit complement. CONCLUSIONS: Vaccination with NP-polySA-KLH, but not polySA-KLH, resulted in a consistent high titer antibody response. We are now conducting a de-escalation dosing study with NP-polySA-KLH to better assess the immunogenicity, toxicities, and optimal dose of this vaccine. We plan to incorporate this vaccine as a component of a polyvalent vaccine with GM2, fucosylated GM1, and Globo H to target SCLC.     

Sialyl Tn is a frequently expressed antigen in colorectal cancer: No correlation with patient prognosis.

Immunohistochemical expression of sialyl Tn antigen (STn), previously claimed to be a prognostic factor in colorectal cancer, was evaluated in 239 patients with colorectal adenocarcinoma. Formalin-fixed, paraffin-embedded specimens were stained with the monoclonal antibody C1282. STn immunoreactivity was seen in 189 of 239 tumors (79%). There was no significant correlation between STn immunoreactivity and Dukes stage, tumor location, histological type or gender. However, STn was significantly more often expressed in younger patients. There was so significant difference in survival between STn-negative patients (median survival 68 months) and STn-positive patients (median survival 79 months). In a Cox multivariate analysis, Dukes stage was the strongest predictor of outcome, followed by the age of the patient, whereas STn did not provide any prognostic information.     

Humoral immune response to a therapeutic polyvalent cancer vaccine after complete resection of thick primary melanoma and sentinel lymphadenectomy.

PURPOSE: A therapeutic polyvalent cancer vaccine (Canvaxin vaccine; CancerVax Corp, Carlsbad, CA) induces antibodies to a glycoprotein tumor-associated antigen (TA90). However, endogenous immune responses to TA90 have also been reported. This study examined anti-TA90 antibody responses with respect to the survival of patients who received adjuvant vaccine immunotherapy after resection of thick (> or = 4 mm) primary cutaneous melanoma. PATIENTS AND METHODS: Serum specimens were obtained from 54 patients immediately before and then 1, 2, 4, and 6 months after wide local excision of thick primary cutaneous melanoma and sentinel lymphadenectomy. All patients were offered adjuvant therapies with the vaccine, high-dose interferon, or other agents. An enzyme-linked immunosorbent assay was used to determine serial serum titers of immunoglobulin G (IgG) and IgM antibodies against TA90. These titers were correlated with clinical course. RESULTS: Forty-three patients chose vaccine therapy, and 11 patients chose postoperative observation. Preoperative anti-TA90 IgG and IgM titers were similar for vaccine and observation groups (P =.184). At a median follow-up of 26 months, univariate analysis of Cox regression showed that disease-free survival and overall survival of vaccine patients were significantly correlated with maximal IgM response (P =.0006 and.006, respectively) but not with maximal IgG response (P =.73 and.95, respectively). Neither response predicted survival in the observation group. CONCLUSION: Postoperative vaccine therapy may enhance IgG and IgM immune responses to TA90 after surgical resection, but only the IgM response is correlated with improved survival. These findings may become useful to guide selection of patients for postoperative adjuvant therapy of high-risk melanoma.     

Peptide and carbohydrate vaccines in relapsed prostate cancer: immunogenicity of synthetic vaccines in man--clinical trials at Memorial Sloan-Kettering Cancer Center.

Men with rising prostate-specific antigen (PSA) levels after primary therapies such as prostatectomy or radiotherapy represent a unique group for whom no standard treatment option exists. A variety of approaches including expectant monitoring, dietary modification, hormonal therapy, and alternative medicines have shown an impact on the rate of increase in PSA, but the overall effect on survival remains controversial. At Memorial Sloan-Kettering Cancer Center, we have focused our treatment approach on this cohort of patients in a series of phase I monovalent carbohydrate and glycoprotein-conjugate vaccine trials using the patients' immune system to generate an antitumor response. These synthetic vaccines are conjugated to keyhole limpet hemocyanin (KLH) and given with the immunologic adjuvant QS21 as five subcutaneous vaccines over 26 weeks. All patients generated specific high-titer immunoglobulin M (IgM) and/or IgG antibodies, some of which were able to mediate complement lysis. Preliminary data suggest that these vaccines may impact on the rate of increase in posttreatment PSA slopes compared with pre-PSA values. The impact of vaccine therapy on the PSA slope and its effect on the time to radiographic progression are the current focus of a forthcoming phase II trial. Vaccines may offer an alternative treatment option for the patient who has relapsed early following primary therapies.     

Idiotypic protein-pulsed dendritic cell vaccination in multiple myeloma

Idiotypic protein (Id) produced by myeloma cells is clone-specific and may be a suitable tumor-specific antigen for immune targeting. Advances in dendritic cell (DC) technology suggest the opportunity for using this potent antigen presentation system to deliver myeloma Id to the autologous host to elicit anti-tumor immune responses. We have generated DCs from adherent PBMCs from 6 patients with IgG myeloma. These cells were pulsed with the autologous Id and a control vaccine, KLH, and re-infused i.v. back to the patients on 3 separate occasions. Immune responses to KLH and autologous Id were measured and clinical responses monitored. We found that all treatments were well tolerated without any side effects. All patients developed both B- and T-cell responses to KLH, suggesting the integrity of the host immune system to mount immune responses to an antigen delivered using our vaccination strategy. Id-specific responses were also observed. PBMC proliferative responses to Id were observed in 5 of the 6 patients following treatment. In 2 patients, the responses were associated with the production of IFN-gamma. There were also increases in cytotoxic T-cell precursor frequencies for Id-pulsed autologous targets in 3 patients. B-cell responses characterized by the production of anti-Id IgM occurred in 3 and anti-Id IgG in 4 of the 5 evaluated patients. In 1 patient, a modest (25%) but consistent drop in the serum Id level was observed. Id-pulsed DC vaccination can therefore elicit potentially useful anti-myeloma immune responses in patients with multiple myeloma.     

Phase III multicenter clinical trial of the sialyl-TN (STn)-keyhole limpet hemocyanin (KLH) vaccine for metastatic breast cancer

Purpose.

This double-blind, randomized, phase III clinical trial evaluated time to progression (TTP) and overall survival in women with metastatic breast cancer (MBC) who received sialyl-TN (STn) keyhole limpet hemocyanin (KLH) vaccine. Secondary endpoints included vaccine safety and immune response.

Experimental design.

The study population consisted of 1,028 women with MBC across 126 centers who had previously received chemotherapy and had had either a complete or a partial response or no disease progression. All women received one-time i.v. cyclophosphamide (300 mg/m²) 3 days before s.c. injection of 100 μg STn-KLH plus adjuvant (treatment group) or 100 μg KLH plus adjuvant (control group) at weeks 0, 2, 5, and 9. Subsequently, STn-KLH without adjuvant or KLH without adjuvant was then administered monthly for 4 months, and then quarterly until disease progression, without cyclophosphamide.

Results.

STn-KLH vaccine was well tolerated; patients had mild to moderate injection-site reactions and reversible flu-like symptoms. Week-12 antibody testing revealed high specific IgG titers and a high rate of IgM-to-IgG seroconversion; the median IgG titers in STn-KLH recipients were 320 (anti-ovine submaxillary mucin) and 20,480 (anti-STn), with no detectable antimucin antibodies in the control group. The TTP was 3.4 months in the treatment group and 3.0 months in the control group. The median survival times were 23.1 months and 22.3 months, respectively.

Conclusions.

Although STn-KLH was well tolerated in this largest to date metastatic breast cancer vaccine trial, no overall benefit in TTP or survival was observed. Lessons were learned for future vaccine study designs.