Isoform specific anti-TGFß therapy enhances antitumor efficacy in mouse models of cancer.

TGFß is a potential target in cancer treatment due to its dual role in tumorigenesis and homeostasis. However, the expression of TGFß and its inhibition within the tumor microenvironment has mainly been investigated in stroma-heavy tumors. Using B16 mouse melanoma and CT26 colon carcinoma as models of stroma-poor tumors, we demonstrate that myeloid/dendritic cells are the main sources of TGFß1 and TGFß3. Depending on local expression of TGFß isoforms, isoform specific inhibition of either TGFß1 or TGFß3 may be effective. The TGFß signature of CT26 colon carcinoma is defined by TGFß1 and TGFß1 inhibition results in tumor delay; B16 melanoma has equal expression of both isoforms and inhibition of either TGFß1 or TGFß3 controls tumor growth. Using T cell functional assays, we show that the mechanism of tumor delay is through and dependent on enhanced CD8+ T cell function. To overcome the local immunosuppressive environment, we found that combining TGFß inhibition with immune checkpoint blockade results in improved tumor control. Our data suggest that TGFß inhibition in stroma poor tumors shifts the local immune environment to favor tumor suppression.

Toxicological and pharmacological assessment of AGEN1884, a novel human IgG1 anti-CTLA-4 antibody.

CTLA-4 and CD28 exemplify a co-inhibitory and co-stimulatory signaling axis that dynamically sculpts the interaction of antigen-specific T cells with antigen-presenting cells. Anti-CTLA-4 antibodies enhance tumor-specific immunity through a variety of mechanisms including: blockade of CD80 or CD86 binding to CTLA-4, repressing regulatory T cell function and selective elimination of intratumoral regulatory T cells via an Fcγ receptor-dependent mechanism. AGEN1884 is a novel IgG1 antibody targeting CTLA-4. It potently enhanced antigen-specific T cell responsiveness that could be potentiated in combination with other immunomodulatory antibodies. AGEN1884 was well-tolerated in non-human primates and enhanced vaccine-mediated antigen-specific immunity. AGEN1884 combined effectively with PD-1 blockade to elicit a T cell proliferative response in the periphery. Interestingly, an IgG2 variant of AGEN1884 revealed distinct functional differences that may have implications for optimal dosing regimens in patients. Taken together, the pharmacological properties of AGEN1884 support its clinical investigation as a single therapeutic and combination agent.

Process development for production and purification of the Schistosoma mansoni Sm14 antigen.

The trematode Schistosoma mansoni Sm14 antigen was expressed in the yeast Pichia pastoris and secreted into the culture medium at yields of approximately 250 mg L-1. Sm14 belongs to a family of fatty-acid binding proteins and appears to play an important role in uptake, transport, and compartmentalization of lipids in S. mansoni and it is a potential vaccine candidate in both humans and domesticated animals. The Sm14 gene was codon-optimized for expression in P. pastoris, and placed under transcription of the strong methanol inducible AOX1 promoter. Mut+ transformants were selected and used in fed-batch cultivation using a 2.5L fermenter equipped with an on-line methanol control system in order to maintain constant methanol levels during induction. Optimal conditions for the expression of Sm14 by P. pastoris were found to be: dissolved oxygen at 40%, temperature of 25 °C, pH 5.0, and a constant methanol concentration of 1 gL-1. Our results show that a correctly processed Sm14 was secreted into the culture medium at levels of approximately 250  mg L-1. Sm14 from clarified culture medium was purified using a two-step procedure: anion-exchange chromatography followed by hydrophobic interaction chromatography, resulting in >95% purity with a final yield of 40% from the starting cell culture medium. This product has been tested in preliminary clinical trials and shown to elicit an antibody response with no adverse reactions.

Expression and clinical significance of MAGE and NY-ESO-1 cancer-testis antigens in adenoid cystic carcinoma of the head and neck.

BACKGROUND: Adenoid cystic carcinoma (ACC) of the head and neck is a rare but highly malignant tumor. Cancer-testis antigens (CTAs) represent an immunogenic family of cancer-specific proteins and thus represent an attractive target for immunotherapy. METHODS: Eighty-four cases of ACC were identified, the CTAs pan-Melanoma antigen (pan-MAGE; M3H67) and New York esophageal squamous cell carcinoma (NY-ESO-1; E978) were detected immunohistochemically (IHC) and correlated with clinical data. RESULTS: Expression of NY-ESO-1 was found in 48 of 84 patients (57.1%) and of pan-MAGE in 28 of 84 patients (31.2%). Median overall survival (OS) in NY-ESO-1 positive versus negative patients was 130.8 and 282.0 months (p = .223), respectively. OS in pan-MAGE positive versus negative patients was 105.3 and 190.5 months, respectively (p = .096). Patients expressing both NY-ESO-1 and pan-MAGE simultaneously had significantly reduced OS with a median of 90.5 months compared with 282.0 months in negative patients (p = .047). CONCLUSION: A significant fraction of patients with ACC show expression of the CTAs NY-ESO-1 and/or pan-MAGE with promising immunotherapeutic implications. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1008-1016, 2016.

PET-based compartmental modeling of (124)I-A33 antibody: quantitative characterization of patient-specific tumor targeting in colorectal cancer.

PURPOSE: The molecular specificity of monoclonal antibodies (mAbs) directed against tumor antigens has proven effective for targeted therapy of human cancers, as shown by a growing list of successful antibody-based drug products. We describe a novel, nonlinear compartmental model using PET-derived data to determine the "best-fit" parameters and model-derived quantities for optimizing biodistribution of intravenously injected (124)I-labeled antitumor antibodies. METHODS: As an example of this paradigm, quantitative image and kinetic analyses of anti-A33 humanized mAb (also known as "A33") were performed in 11 colorectal cancer patients. Serial whole-body PET scans of (124)I-labeled A33 and blood samples were acquired and the resulting tissue time-activity data for each patient were fit to a nonlinear compartmental model using the SAAM II computer code. RESULTS: Excellent agreement was observed between fitted and measured parameters of tumor uptake, "off-target" uptake in bowel mucosa, blood clearance, tumor antigen levels, and percent antigen occupancy. CONCLUSION: This approach should be generally applicable to antibody-antigen systems in human tumors for which the masses of antigen-expressing tumor and of normal tissues can be estimated and for which antibody kinetics can be measured with PET. Ultimately, based on each patient's resulting "best-fit" nonlinear model, a patient-specific optimum mAb dose (in micromoles, for example) may be derived.

Blockade of CTLA-4 promotes the development of effector CD8+ T lymphocytes and the therapeutic effect of vaccination with an attenuated protozoan expressing NY-ESO-1.

The development of cancer immunotherapy has long been a challenge. Here, we report that prophylactic vaccination with a highly attenuated Trypanosoma cruzi strain expressing NY-ESO-1 (CL-14-NY-ESO-1) induces both effector memory and effector CD8(+) T lymphocytes that efficiently prevent tumor development. However, the therapeutic effect of such a vaccine is limited. We also demonstrate that blockade of Cytotoxic T Lymphocyte Antigen 4 (CTLA-4) during vaccination enhances the frequency of NY-ESO-1-specific effector CD8(+) T cells producing IFN-γ and promotes lymphocyte migration to the tumor infiltrate. As a result, therapy with CL-14-NY-ESO-1 together with anti-CTLA-4 is highly effective in controlling the development of an established melanoma.

Epigenetic potentiation of NY-ESO-1 vaccine therapy in human ovarian cancer.

The cancer-testis/cancer-germline antigen NY-ESO-1 is a vaccine target in epithelial ovarian cancer (EOC), but its limited expression is a barrier to vaccine efficacy. As NY-ESO-1 is regulated by DNA methylation, we hypothesized that DNA methyltransferase (DNMT) inhibitors may augment NY-ESO-1 vaccine therapy. In agreement, global DNA hypomethylation in EOC was associated with the presence of circulating antibodies to NY-ESO-1. Pre-clinical studies using EOC cell lines showed that decitabine treatment enhanced both NY-ESO-1 expression and NY-ESO-1-specific CTL-mediated responses. Based on these observations, we performed a phase I dose-escalation trial of decitabine, as an addition to NY-ESO-1 vaccine and doxorubicin liposome (doxorubicin) chemotherapy, in 12 patients with relapsed EOC. The regimen was safe, with limited and clinically manageable toxicities. Both global and promoter-specific DNA hypomethylation occurred in blood and circulating DNAs, the latter of which may reflect tumor cell responses. Increased NY-ESO-1 serum antibodies and T cell responses were observed in the majority of patients, and antibody spreading to additional tumor antigens was also observed. Finally, disease stabilization or partial clinical response occurred in 6/10 evaluable patients. Based on these encouraging results, evaluation of similar combinatorial chemo-immunotherapy regimens in EOC and other tumor types is warranted.

Simultaneous cytoplasmic and nuclear protein expression of melanoma antigen-A family and NY-ESO-1 cancer-testis antigens represents an independent marker for poor survival in head and neck cancer.

The prognosis of head and neck squamous cell carcinoma (HNSCC) patients remains poor. The identification of high-risk subgroups is needed for the development of custom-tailored therapies. The expression of cancer-testis antigens (CTAs) has been linked to a worse prognosis in other cancer types; however, their prognostic value in HNSCC is unclear because only few patients have been examined and data on CTA protein expression are sparse. A tissue microarray consisting of tumor samples from 453 HNSCC patients was evaluated for the expression of CTA proteins using immunohistochemistry. Frequency of expression and the subcellular expression pattern (nuclear, cytoplasmic, or both) was recorded. Protein expression of melanoma antigen (MAGE)-A family CTA, MAGE-C family CTA and NY-ESO-1 was found in approximately 30, 7 and 4% of tumors, respectively. The subcellular expression pattern in particular had a marked impact on the patients' prognosis. Median overall survival (OS) of patients with (i) simultaneous cytoplasmic and nuclear expression compared to (ii) either cytoplasmic or nuclear expression and (iii) negative patients was 23.0 versus 109.0 versus 102.5 months, for pan-MAGE (p < 0.0001), 46.6 versus 50.0 versus 109.0 for MAGE-A3/A4 (p = 0.0074) and 13.3 versus 50.0 versus 100.2 months for NY-ESO-1 (p = 0.0019). By multivariate analysis, these factors were confirmed as independent markers for poor survival. HNSCC patients showing protein expression of MAGE-A family members or NY-ESO-1 represent a subgroup with an extraordinarily poor survival. The development of immunotherapeutic strategies targeting these CTA may, therefore, be a promising approach to improve the outcome of HNSCC patients.

Prostate cancer progression correlates with increased humoral immune response to a human endogenous retrovirus GAG protein.

PURPOSE: Human endogenous retroviruses (HERV) encode 8% of the human genome. While HERVs may play a role in autoimmune and neoplastic disease, no mechanistic association has yet been established. We studied the expression and immunogenicity of a HERV-K GAG protein encoded on chromosome 22q11.23 in relation to the clinical course of prostate cancer. EXPERIMENTAL DESIGN: In vitro expression of GAG-HERV-K was analyzed in panels of normal and malignant tissues, microarrays, and cell lines, and effects of demethylation and androgen stimulation were evaluated. Patient sera were analyzed for seroreactivity to GAG-HERV-K and other self-antigens by ELISA and seromics (protein array profiling). RESULTS: GAG-HERV-K expression was most frequent in prostate tissues and regulated both by demethylation of the promoter region and by androgen stimulation. Serum screening revealed that antibodies to GAG-HERV-K are found in a subset of patients with prostate cancer (33 of 483, 6.8%) but rarely in male healthy donors (1 of 55, 1.8%). Autoantibodies to GAG-HERV-K occurred more frequently in patients with advanced prostate cancer (29 of 191 in stage III-IV, 21.0%) than in early prostate cancer (4 of 292 in stages I-II, 1.4%). Presence of GAG-HERV-K serum antibody was correlated with worse survival of patients with prostate cancer, with a trend for faster biochemical recurrence in patients with antibodies to GAG-HERV-K. CONCLUSIONS: Preferential expression of GAG-HERV-K ch22q11.23 in prostate cancer tissue and increased frequency of autoantibodies observed in patients with advanced prostate cancer make this protein one of the first bona fide retroviral cancer antigens in humans, with potential as a biomarker for progression and biochemical recurrence rate of prostate cancer. Clin Cancer Res; 19(22); 6112-25. ©2013 AACR.

Process development and production of cGMP grade Melan-A for cancer vaccine clinical trials.

Melan-A is a cancer testis antigen commonly found in melanoma, and has been shown to stimulate the body's immune response against cancerous cells. We have developed and executed a process utilizing current good manufacturing practices (cGMP) to produce the 6 times-His tagged protein in C41DE3 Escherichia coli for use in Phase I clinical trials. Approximately 11 g of purified Melan-A were produced from a 20 L fed-batch fermentation. Purification was achieved through a three column process utilizing immobilized metal affinity, anion exchange, and cation exchange chromatography with a buffer system optimized for low-solubility, high LPS binding capacity proteins. The host cell proteins, residual DNA, and endotoxin concentration were well below limits for a prescribed dose with a final purity level of 91%.

Rebmab200, a humanized monoclonal antibody targeting the sodium phosphate transporter NaPi2b displays strong immune mediated cytotoxicity against cancer: a novel reagent for targeted antibody therapy of cancer.

NaPi2b, a sodium-dependent phosphate transporter, is highly expressed in ovarian carcinomas and is recognized by the murine monoclonal antibody MX35. The antibody had shown excellent targeting to ovarian cancer in several early phase clinical trials but being murine the antibody's full therapeutic potential could not be explored. To overcome this impediment we developed a humanized antibody version named Rebmab200, expressed in human PER.C6® cells and cloned by limiting dilution. In order to select a clone with high therapeutic potential clones were characterized using a series of physicochemical assays, flow cytometry, real-time surface plasmon resonance, glycosylation analyses, immunohistochemistry, antibody-dependent cell-mediated cytotoxicity, complement-dependent-cytotoxicity assays and quantitative PCR. Comparative analyses of Rebmab200 and MX35 monoclonal antibodies demonstrated that the two antibodies had similar specificity for NaPi2b by flow cytometry with a panel of 30 cell lines and maintained similar kinetic parameters. Robust and high producer cell clones potentially suitable for use in manufacturing were obtained. Rebmab200 antibodies were assessed by immunohistochemistry using a large panel of tissues including human carcinomas of ovarian, lung, kidney and breast origin. An assessment of its binding towards 33 normal human organs was performed as well. Rebmab200 showed selected strong reactivity with the tested tumor types but little or no reactivity with the normal tissues tested confirming its potential for targeted therapeutics strategies. The remarkable cytotoxicity shown by Rebmab200 in OVCAR-3 cells is a significant addition to the traits of stability and productivity displayed by the top clones of Rebmab200. Antibody-dependent cell-mediated toxicity functionality was confirmed in repeated assays using cancer cell lines derived from ovary, kidney and lung as targets. To explore use of this antibody in clinical trials, GMP production of Rebmab200 has been initiated. As the next step of development, Phase I clinical trials are now planned for translation of Rebmab200 into the clinic.

NY-ESO-1-specific immunological pressure and escape in a patient with metastatic melanoma.

During cancer progression, malignant cells may evade immunosurveillance. However, evidence for immunological escape in humans is scarce. We report here the clinical course of a melanoma patient whose initial tumor was positive for the antigens NY-ESO-1, MAGE-C1, and Melan-A. Upon immunization with a recombinant vaccinia/fowlpox NY-ESO-1 construct, the patient experienced a mixed clinical response and spreading of the NY-ESO-1 epitopes in the CD4+ T cell compartment. After NY-ESO-1 protein + CpG immunization, the patient's anti-NY-ESO-1 IgG response increased. Over the following years, progressing lesions were resected and found to be NY-ESO-1-negative while being positive for MAGE-C1, Melan-A, and MHC-I. The fatal, inoperable brain metastasis was analyzed after his death and also proved to be NY-ESO-1-negative, while being positive for MAGE-C1 and Melan-A, as well as MHC-I. We propose that cancer control and cancer escape in this patient were governed by NY-ESO-1-specific immunological pressure. Our findings provide evidence for the existence of immunoediting and immunoescape in this cancer patient.

Evaluation of arginine deiminase treatment in melanoma xenografts using (18)F-FLT PET.

PURPOSE: This study aims to develop a molecular imaging strategy for response assessment of arginine deiminase (ADI) treatment in melanoma xenografts using 3'-[(18)F]fluoro-3'-deoxythymidine ([(18)F]-FLT) positron emission tomography (PET). PROCEDURES: F-FLT response to ADI therapy was studied in preclinical models of melanoma in vitro and in vivo. The molecular mechanism of response to ADI therapy was investigated, with a particular emphasis on biological pathways known to regulate (18)F-FLT metabolism. RESULTS: Proliferation of SK-MEL-28 melanoma tumors was potently inhibited by ADI treatment. However, no metabolic response was observed in FLT PET, presumably based on the known ADI-induced degradation of PTEN, followed by instability of the tumor suppressor p53 and a relative overexpression of thymidine kinase 1, the enzyme mainly responsible for intracellular FLT processing. CONCLUSION: The specific pharmacological properties of ADI preclude using (18)F-FLT to evaluate clinical response in melanoma and argue for further studies to explore the use of other clinically applicable PET tracers in ADI treatment.

Antibody-based therapy in colorectal cancer.

Treatment in patients with nonresectable and resectable colorectal cancer at the advanced stage is challenging, therefore intensive strategies such as chemotherapy, signaling inhibitors and monoclonal antibodies (mAbs) to control the disease are required. mAbs are particularly promising tools owing to their target specificities and strong antitumor activities through multiple mechanisms, as shown by rituximab in B-cell non-Hodgkin's lymphoma and trastuzumab in breast cancer. Three mAbs (cetuximab, bevacizumab and panitumumab) have been approved for the treatment of colorectal cancer in the USA and many other mAbs are being tested in clinical trials. The potential of antibody therapy is associated with several mechanisms including interference of vital signaling pathways targeted by the antibody and immune cytotoxicity selectively directed against tumor cells by tumor-bound antibody through the Fc portion of the antibody, such as antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity. Moreover, recent experimental findings have shown that immune complexes formed by therapeutic mAbs with tumor-released antigens could augment the induction of tumor-specific cytotoxic CD8(+) T cells through activation of APCs. In addition, antibodies targeting immune checkpoints on hematopoietic cells have recently opened a new avenue for the treatment of cancer. In this review, we focus on mAb treatment in colorectal cancer and its immunological aspects.

A Pilot Study of Anti-CTLA4 Antibody Ipilimumab in Patients with Synovial Sarcoma.

Background. Patients with recurrent synovial sarcomas have few options for systemic therapy. Since they express large amounts of endogenous CT (cancer testis) antigens such as NY-ESO-1, we investigated the clinical activity of single agent anti-CTLA4 antibody ipilimumab in patients with advanced or metastatic synovial sarcoma. Methods. A Simon two-stage phase II design was used to determine if there was sufficient activity to pursue further. The primary endpoint was tumor response rate by RECIST 1.0. Patients were treated with ipilimumab 3 mg/kg intravenously every 3 weeks for three cycles and then restaged. Retreatment was possible for patients receiving an extra three-week break from therapy. Sera and peripheral blood mononuclear cells were collected before and during therapy to assess NY-ESO-1-specific immunity. Results. Six patients were enrolled and received 1-3 cycles of ipilimumab. All patients showed clinical or radiological evidence of disease progression after no more than three cycles of therapy, for a RECIST response rate of 0%. The study was stopped for slow accrual, lack of activity, and lack of immune response. There was no evidence of clinically significant either serologic or delayed type hypersensitivity responses to NY-ESO-1 before or after therapy. Conclusion. Despite high expression of CT antigens by synovial sarcomas of patients treated in this study, there was neither clinical benefit nor evidence of anti-CT antigen serological responses. Assessment of the ability of synovial sarcoma cell lines to present cancer-germ cell antigens may be useful in determining the reason for the observed lack of immunological or clinical activity.

A novel human-derived antibody against NY-ESO-1 improves the efficacy of chemotherapy.

We investigated whether antibodies against intracellular tumor-associated antigens support tumor-specific immunity when administered together with a treatment that destroys the tumor. We propose that released antigens form immune complexes with the antibodies, which are then efficiently taken up by dendritic cells. We cloned the first human monoclonal antibodies against the Cancer/Testis (CT) antigen, NY-ESO-1. We tested whether the monoclonal anti-NY-ESO-1 antibody (12D7) facilitates cross-presentation of a NY-ESO-1-derived epitope by dendritic cells to human CD8+ T cells, and whether this results in the maturation of dendritic cells in vitro. We investigated the efficacy of 12D7 in combination with chemotherapy using BALB/c mice bearing syngeneic CT26 tumors that express intracellular NY-ESO-1. Human dendritic cells that were incubated with NY-ESO-1:12D7 immune complexes efficiently stimulated NY-ESO-1(157-165)/HLA-A2-specific human CD8+ T cells to produce interferon-γ, whereas NY-ESO-1 alone did not. Furthermore, the incubation of dendritic cells with NY-ESO-1:12D7 immune complexes resulted in the maturation of dendritic cells. Treatment of BALB/c mice that bear CT26/NY-ESO-1 tumors with 5-fluorouracil (5-FU) plus 12D7 was significantly more effective than chemotherapy alone. We propose systemic injection of monoclonal antibodies (mAbs) against tumor-associated antigens plus a treatment that promotes the local release of those antigens resulting in immune complex formation as a novel therapeutic modality for cancer.

Overcoming regulatory T-cell suppression by a lyophilized preparation of Streptococcus pyogenes.

Cancer vaccines have yet to yield clinical benefit, despite the measurable induction of humoral and cellular immune responses. As immunosuppression by CD4(+) CD25(+) regulatory T (Treg) cells has been linked to the failure of cancer immunotherapy, blocking suppression is therefore critical for successful clinical strategies. Here, we addressed whether a lyophilized preparation of Streptococcus pyogenes (OK-432), which stimulates Toll-like receptors, could overcome Treg-cell suppression of CD4(+) T-cell responses in vitro and in vivo. OK-432 significantly enhanced in vitro proliferation of CD4(+) effector T cells by blocking Treg-cell suppression and this blocking effect depended on IL-12 derived from antigen-presenting cells. Direct administration of OK-432 into tumor-associated exudate fluids resulted in a reduction of the frequency and suppressive function of CD4(+) CD25(+) Foxp3(+) Treg cells. Furthermore, when OK-432 was used as an adjuvant of vaccination with HER2 and NY-ESO-1 for esophageal cancer patients, NY-ESO-1-specific CD4(+) T-cell precursors were activated, and NY-ESO-1-specific CD4(+) T cells were detected within the effector/memory T-cell population. CD4(+) T-cell clones from these patients had high-affinity TCRs and recognized naturally processed NY-ESO-1 protein presented by dendritic cells. OK-432 therefore inhibits Treg-cell function and contributes to the activation of high-avidity tumor antigen-specific naive T-cell precursors.

Imaging of tumor vascularization using fluorescence molecular tomography to monitor arginine deiminase treatment in melanoma.

Based on their inability to express argininosuccinate synthetase (ASS), some cancer entities feature the characteristic of L-arginine (Arg) auxotrophy. This inability to intrinsically generate Arg makes them applicable for arginine deiminase (ADI) treatment, an Arg-depleting drug. Arg is also used for the synthesis of endothelial nitric oxide (NO), which mainly confers vasodilatation but is also considered to have a major influence on tumor vascularization. The purpose of this study was to define changes in tumor vasculature in an ADI-treated melanoma xenograft mouse model using the blood pool agent AngioSense 750 and fluorescence molecular tomography (FMT). We used an ASS-negative melanoma xenograft mouse model and subjected it to weekly ADI treatment. Changes in tumor size were measured, and alterations in tumor vasculature were depicted by FMT and CD31 immunohistochemistry (IHC). On ADI treatment and effective antitumor therapy, we observed a drop in NO plasma levels and visualized changes in tumor vascularization with FMT and IHC. ADI treatment in melanoma xenografts has a tumor-reducing effect, which can be noninvasively imaged by quantifying tumor vascularization with FMT and IHC.

Effect of Montanide and poly-ICLC adjuvant on human self/tumor antigen-specific CD4+ T cells in phase I overlapping long peptide vaccine trial.

Vaccination of patients with ovarian cancer with overlapping long peptides (OLP) from cancer-testis antigen NY-ESO-1 and poly-ICLC in Montanide-ISA-51 (Montanide) was found to consistently induce integrated immune responses (antibody, CD4(+), and CD8(+) T cells). Using detailed methods, we investigated the respective effects of poly-ICLC and Montanide adjuvant on pre- and postvaccine NY-ESO-1-specific CD4(+) T cells, because of their central function for induction and maintenance of both antibody and CD8(+) T cells. Polyclonal NY-ESO-1-specific CD4(+) T-cell lines were generated from 12 patients using CD154-based selection of precursors before and after vaccination with (i) OLP alone, (ii) OLP in Montanide, or (iii) OLP and poly-ICLC in Montanide. Kinetics, quantification, fine specificity, avidity, and cytokine-producing pattern were analyzed in depth and compared between vaccine cohorts. Vaccination with OLP alone did not elicit CD4(+) T-cell responses; it suppressed high-avidity CD4(+) T-cell precursors that recognized naturally processed NY-ESO-1 protein before vaccination. Emulsification of OLP in Montanide was required for the expansion of high-avidity NY-ESO-1-specific CD4(+) T-cell precursors. Poly-ICLC significantly enhanced CD4(+) Th1 responses while suppressing the induction of interleukin (IL)-4-producing Th2 and IL-9-producing Th9 cells. In summary, Montanide and poly-ICLC had distinct and cooperative effects for the induction of NY-ESO-1-specific Th1 cells and integrated immune responses by OLP vaccination. These results support the use of admixing poly-ICLC in Montanide adjuvant to rapidly induce antitumor type I immune responses by OLP from self/tumor antigens in human cancer vaccines.

Phase I trial of overlapping long peptides from a tumor self-antigen and poly-ICLC shows rapid induction of integrated immune response in ovarian cancer patients.

PURPOSE: Long peptides are efficiently presented to both CD4(+) and CD8(+) T cells after intracellular processing by antigen-presenting cells. To investigate the safety and in vivo immunogenicity of synthetic overlapping long peptides (OLP) from a human tumor self-antigen, we conducted a phase I clinical trial with OLP from cancer-testis antigen NY-ESO-1 in various adjuvant combinations. EXPERIMENTAL DESIGN: Twenty-eight patients with advanced ovarian cancer in second or third remission were enrolled sequentially in three cohorts and received at least one vaccination. Patients in Cohort 1 (n = 4) received 1.0 mg OLP, Cohort 2 (n = 13) received OLP in Montanide-ISA-51, and Cohort 3 (n = 11) received OLP + 1.4 mg Poly-ICLC in Montanide-ISA-51 on weeks 1, 4, 7, 10, and 13. Humoral and cellular responses were evaluated by standardized immunomonitoring techniques (ELISA, ELISPOT assay, intracellular cytokine staining, and tetramer staining). RESULTS: The vaccine was generally well tolerated with injection site reactions and fatigue that resolved. NY-ESO-1-specific antibody and CD8(+) T cells were undetectable after vaccination with OLP alone, but were found in 6 of 13 (46%) and 8 of 13 (62%) patients, respectively, after vaccination with OLP+Montanide, and in 10 of 11 (91%) and 10 of 11 (91%) patients, respectively, after vaccination with OLP+Montanide+Poly-ICLC. NY-ESO-1-specific CD4(+) T cells were detected in all patients with greater frequency and polyclonality when Montanide-ISA-51 was used for vaccination. Inclusion of Poly-ICLC as an adjuvant further accelerated the induction of NY-ESO-1-specific immune responses. CONCLUSIONS: The current study shows that NY-ESO-1 OLP vaccine is safe and rapidly induces consistent integrated immune responses (antibody, CD8(+) and CD4(+)) in nearly all vaccinated patients when given with appropriate adjuvants.