PD-L1 expression predicts efficacy in the phase II SPiReL trial with MVP-S, pembrolizumab, and low-dose CPA in R/R DLBCL.

BACKGROUND: Patients with relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL) have limited treatment options. METHODS: R/R DLBCL patients, who were mostly ineligible for ASCT due to age or comorbidities, were treated with maveropepimut-S (MVP-S, previously DPX-Survivac) a survivin directed T cell educating therapy, pembrolizumab, and intermittent low-dose cyclophosphamide. FINDINGS: We identified, using univariate analysis, a subset of patients with enhanced ORR, PFS and DOR. Patients with baseline CD20+/PD-L1 expression had an ORR of 46% (6/13) and the disease control rate was 10/13 (77%). The PFS and OS of the positive CD20+/PD-L1 patients were 7.1 months and 17.4 months, whereas in the intent-to-treat (ITT) population of 25 enrolled patients, the ORR was 28% (7/25), median PFS and OS were 4.2 months and 10.1 months respectively. A total of 6/7 clinical responders occurred in CD20+/PD-L1 patients. The regimen was well-tolerated, requiring only minor dose modifications and one discontinuation. Grade 1 or 2 injection site reactions occurred in 14/25, (56%). Statistically significant associations were also seen between PFS and; injection site reactions; and ELISpot response to survivin peptides, both identifying the mechanistic importance of specific immune responses to survivin. INTERPRETATION: This immunotherapy combination was found to be active and safe in this clinically challenging patient population.

IRX-2 natural cytokine biologic for immunotherapy in patients with head and neck cancers.

Head and neck squamous cell carcinoma (HNSCC) is an immunosuppressive malignancy characterized by tumor-driven immune-system abnormalities that contribute to disease progression. For patients with surgically resectable HNSCC, treatment is often curative surgery followed by irradiation or chemoradiation in high-risk settings to reduce the risk of recurrence. Poor survival and considerable morbidity of current treatments suggest the need for new therapeutic modalities that can improve outcomes. Defects in antitumor immunity of HNSCC patients include suppressed dendritic cell (DC) maturation, deficient antigen-presenting cell function, compromised natural killer (NK)-cell cytotoxicity, increased apoptosis of activated T lymphocytes, and impaired immune-cell migration to tumor sites. Strategies for relieving immunosuppression and restoring antitumor immune functions could benefit HNSCC patients. IRX-2 is a primary cell-derived biologic consisting of physiologic levels of T-helper type 1 cytokines produced by stimulating peripheral blood mononuclear cells of normal donors with phytohemagglutinin. The primary active components in IRX-2 are IL2, IL1ß, IFNγ, and TNFα. In vitro, IRX-2 acts on multiple immune-system cell types, including DCs, T cells, and NK cells, to overcome tumor-mediated immunosuppression. In clinical settings, IRX-2 is administered as part of a 21-day neoadjuvant regimen, which includes additional pharmacologic agents (low-dose cyclophosphamide, indomethacin, and zinc) to promote anticancer immunoresponses. In a Phase IIA trial in 27 patients with surgically resectable, previously untreated HNSCC, neoadjuvant IRX-2 increased infiltration of T cells, B cells, and DCs into tumors and was associated with radiological reductions in tumor size. Event-free survival was 64% at 2 years, and overall 5-year survival was 65%. Follow-up and data analysis are under way in the multicenter, randomized, Phase IIB INSPIRE trial evaluating the IRX-2 regimen as a stand-alone therapy for activating the immune system to recognize and attack tumors.

Increased immune infiltration and chemokine receptor expression in head and neck epithelial tumors after neoadjuvant immunotherapy with the IRX-2 regimen.

IRX-2 is an injectable cancer immunotherapy composed of cytokines purified from stimulated normal-donor peripheral blood mononuclear cells. In a phase 2a trial (n = 27), neoadjuvant IRX-2 significantly increased lymphocyte infiltration (LI) into resected head and neck tumors and was associated with changes in fibrosis and necrosis. Event-free survival was 65% at 2 years, and overall survival 65% at 5 years. Overall survival was longer for patients with LI greater versus lower than the median. This substudy of the mechanisms responsible for the increase in LI with neoadjuvant IRX-2 employed multiplex immunohistochemistry (IHC) and transcriptome analysis to interrogate matched pre- and post-treatment tumor specimens from 7 available phase 2a trial patients. Multiplex IHC showed substantial increases in CD68-expressing cells (5 patients), T-cell density (4 patients), and PDL1 mean fluorescent intensity (4 patients). Consistent with IRX-2 activation of multiple immune cells, transcriptome analysis showed mean increases in expression of genes associated with NK cells, B cells, CD4+ T cells, CD8+ T cells, and dendritic cells, but not of genes associated with neutrophils. There were increases in mean expression of genes for most immune subsets, most markedly (2- to 3-fold) for B cells and dendritic cells. Mean increases in gene expression for chemokines suggest that tumor LI may be driven in part by IRX-2-induced production of chemo-attractants. Upregulation of checkpoint genes including PDL1 and CTLA4 along with increased T-cell infiltration suggests a functional antitumor immune response such that the efficacy of IRX-2 may be enhanced by combination with immune checkpoint inhibitors.

Serum-derived carcinoembryonic antigen (CEA) activates fibroblasts to induce a local re-modeling of the extracellular matrix that favors the engraftment of CEA-expressing tumor cells.

Elevated levels of the carcinoembryonic antigen (CEA; CEACAM5) in the serum of colorectal cancer (CRC) patients represent a clinical biomarker that correlates with disease recurrence. However, a mechanistic role for soluble CEA (sCEA) in tumor progression and metastasis remains to be established. In our study, we report that sCEA acts as a paracrine factor, activating human fibroblasts by signaling through both the STAT3 and AKT1-mTORC1 pathways, promoting their transition to a cancer-associated fibroblast (CaF) phenotype. sCEA-activated fibroblasts express and secrete higher levels of fibronectin, including cellular EDA+ -fibronectin (Fn-EDA) that selectively promote the implantation and adherence of CEA-expressing cancer cells. Immunohistochemical analyses of liver tissues derived from CRC patients with elevated levels of sCEA reveal that the expression of cellular Fn-EDA co-registers with CEA-expressing liver metastases. Taken together, these findings indicate a direct role for sCEA as a human fibroblast activation factor, in priming target tissues for the engraftment of CEA-expressing cancer cells, through the differentiation of tissue-resident fibroblasts, resulting in a local change in composition of the extracellular matrix.

Management of newly diagnosed high-risk and intermediate-risk follicular lymphoma with 90 Y ibritumomab tiuxetan in a phase II study.

Five-year overall survival for high-risk Follicular Lymphoma International Prognostic Index follicular lymphoma is only approximately 50% compared with 90% for low risk. To evaluate an approach to improve upon this poor outcome, we completed an exploratory phase II trial of intensified treatment for patients with intermediate and high-risk follicular lymphoma. Front-line treatment with chemo-immunotherapy consisting of rituximab, cyclophosphamide, vincristine, doxorubicin, and prednisone was followed by radio- immunotherapy with 90-Yttrium ibritumomab tiuxetan consolidation, and 2 years of rituximab maintenance. The 5-year overall survival for intermediate and high-risk patients was 88% and 83%, respectively. Of 33 enrolled patients, 3 were off study before receiving radio-immunotherapy. Three months post radio-immunotherapy, 28/33 (85%) patients had achieved complete response including 6 patients who had only a partial response to chemo-immunotherapy and converted to complete response after radio-immunotherapy. The 5-year progression-free survival for intermediate and high risk was 79% and 58%, respectively. Nine of 19 patients with molecular markers patients remain in molecular and clinical complete remission with a median follow-up of 48 months (range 3-84 months). Post radio-immunotherapy, hematologic toxicities were mostly grade 1 and 2. However, asymptomatic grade 3 or 4 thrombocytopenia and neutropenia occurred in 11%-36% and 10%-24% of patients, respectively. Myelodysplastic syndrome occurred in 1 patient 4 years post treatment. Whereas many patients had prolonged B-cell reduction and low immunoglobulin levels post treatment, previous immunities to rubella were maintained. More aggressive upfront approaches such as this may benefit higher risk follicular lymphoma, but confirmatory trials are required. http://www.clinicaltrials.gov: NCT01446562.

Anti-PD-1 increases the clonality and activity of tumor infiltrating antigen specific T cells induced by a potent immune therapy consisting of vaccine and metronomic cyclophosphamide.

BACKGROUND: Future cancer immunotherapies will combine multiple treatments to generate functional immune responses to cancer antigens through synergistic, multi-modal mechanisms. In this study we explored the combination of three distinct immunotherapies: a class I restricted peptide-based cancer vaccine, metronomic cyclophosphamide (mCPA) and anti-PD-1 treatment in a murine tumor model expressing HPV16 E7 (C3). METHODS: Mice were implanted with C3 tumors subcutaneously. Tumor bearing mice were treated with mCPA (20 mg/kg/day PO) for seven continuous days on alternating weeks, vaccinated with HPV16 E749-57 peptide antigen formulated in the DepoVax (DPX) adjuvanting platform every second week, and administered anti-PD-1 (200 µg/dose IP) after each vaccination. Efficacy was measured by following tumor growth and survival. Immunogenicity was measured by IFN-γ ELISpot of spleen, vaccine draining lymph nodes and tumor draining lymph nodes. Tumor infiltration was measured by flow cytometry for CD8α+ peptide-specific T cells and RT-qPCR for cytotoxic proteins. The clonality of tumor infiltrating T cells was measured by TCRß sequencing using genomic DNA. RESULTS: Untreated C3 tumors had low expression of PD-L1 in vivo and anti-PD-1 therapy alone provided no protection from tumor growth. Treatment with DPX/mCPA could delay tumor growth, and tri-therapy with DPX/mCPA/anti-PD-1 provided long-term control of tumors. We found that treatment with DPX/mCPA/anti-PD-1 enhanced systemic antigen-specific immune responses detected in the spleen as determined by IFN-γ ELISpot compared to those in the DPX/mCPA group, but immune responses in tumor-draining lymph nodes were not increased. Although no increases in antigen-specific CD8α+ TILs could be detected, there was a trend for increased expression of cytotoxic genes within the tumor microenvironment as well as an increase in clonality in mice treated with DPX/mCPA/anti-PD-1 compared to those with anti-PD-1 alone or DPX/mCPA. Using a library of antigen-specific CD8α+ T cell clones, we found that antigen-specific clones were more frequently expanded in the DPX/mCPA/anti-PD-1 treated group. CONCLUSIONS: These results demonstrate how the efficacy of anti-PD-1 may be improved by combination with a potent and targeted T cell activating immune therapy.

Immunostimulatory Activity of the Cytokine-Based Biologic, IRX-2, on Human Papillomavirus-Exposed Langerhans Cells.

Langerhans cells (LCs) are the antigen-presenting cells of the epithelial layer and are responsible for initiating immune responses against skin and mucosa-invading viruses. Human papillomavirus (HPV)-mediated suppression of LC function is a crucial mechanism of HPV immune evasion, which can lead to persistent infection and development of several human cancers, including cervical, anal, and head and neck cancers. The cell-derived cytokine-based biologic, IRX-2, consists of multiple well-defined cytokines and is broadly active on various immune cell subsets. In this study, we investigated primary human LC activation after exposure to HPV16, followed by treatment with IRX-2 in vitro, and evaluated their subsequent ability to induce HPV16-specific T cells. In contrast to its activity on dendritic cells, HPV16 alone is not sufficient to induce phenotypic and functional activation of LCs. However, IRX-2 induces a significant upregulation of antigen presentation and costimulatory molecules, T helper 1 (Th1)-associated cytokine release, and chemokine-directed migration of LCs pre-exposed to HPV16. Furthermore, LCs treated with IRX-2 after HPV16 exposure induced CD8(+) T-cell responses against specific HLA-A*0201-binding HPV16 T-cell epitopes. The present study suggests that IRX-2 is an attractive immunomodulator for assisting the immune response in eradication of HPV-infected cells, thereby potentially preventing HPV-induced cancers.

Survivin-targeted immunotherapy drives robust polyfunctional T cell generation and differentiation in advanced ovarian cancer patients.

DepoVax™ is an innovative and strongly immunogenic vaccine platform. Survivin is highly expressed in many tumor types and has reported prognostic value. To generate tumor-specific immune response, a novel cancer vaccine was formulated in DepoVax platform (DPX-Survivac) using survivin HLA class I peptides. Safety and immune potency of DPX-Survivac was tested in combination with immune-modulator metronomic cyclophosphamide in ovarian cancer patients. All the patients receiving the therapy produced antigen-specific immune responses; higher dose vaccine and cyclophosphamide treatment generating significantly higher magnitude responses. Strong T cell responses were associated with differentiation of naïve T cells into central/effector memory (CM/EM) and late differentiated (LD) polyfunctional antigen-specific CD4+ and CD8+ T cells. This approach enabled rapid de novo activation/expansion of vaccine antigen-specific CD8+ T cells and provided a strong rationale for further testing to determine clinical benefits associated with this immune activation. These data represent vaccine-induced T cell activation in a clinical setting to a self-tumor antigen previously described only in animal models.

Active idiotypic vaccination versus control immunotherapy for follicular lymphoma.

PURPOSE: Idiotypes (Ids), the unique portions of tumor immunoglobulins, can serve as targets for passive and active immunotherapies for lymphoma. We performed a multicenter, randomized trial comparing a specific vaccine (MyVax), comprising Id chemically coupled to keyhole limpet hemocyanin (KLH) plus granulocyte macrophage colony-stimulating factor (GM-CSF) to a control immunotherapy with KLH plus GM-CSF. PATIENTS AND METHODS: Patients with previously untreated advanced-stage follicular lymphoma (FL) received eight cycles of chemotherapy with cyclophosphamide, vincristine, and prednisone. Those achieving sustained partial or complete remission (n=287 [44%]) were randomly assigned at a ratio of 2:1 to receive one injection per month for 7 months of MyVax or control immunotherapy. Anti-Id antibody responses (humoral immune responses [IRs]) were measured before each immunization. The primary end point was progression-free survival (PFS). Secondary end points included IR and time to subsequent antilymphoma therapy. RESULTS: At a median follow-up of 58 months, no significant difference was observed in either PFS or time to next therapy between the two arms. In the MyVax group (n=195), anti-Id IRs were observed in 41% of patients, with a median PFS of 40 months, significantly exceeding the median PFS observed in patients without such Id-induced IRs and in those receiving control immunotherapy. CONCLUSION: This trial failed to demonstrate clinical benefit of specific immunotherapy. The subset of vaccinated patients mounting specific anti-Id responses had superior outcomes. Whether this reflects a therapeutic benefit or is a marker for more favorable underlying prognosis requires further study.

Therapeutic vaccines and cancer: focus on DPX-0907.

In an attempt to significantly enhance immunogenicity of peptide cancer vaccines, we developed a novel non-emulsion depot-forming vaccine platform called DepoVax™ (DPX). Human leukocyte antigen (HLA)-A2 restricted peptides naturally presented by cancer cells were used as antigens to create a therapeutic cancer vaccine, DPX-0907. In a phase I clinical study, the safety and immune-activating potential of DPX-0907 in advanced-stage breast, ovarian, and prostate cancer patients were examined, following encouraging results in HLA-A2 transgenic mice. The DPX-0907 vaccine was shown to be safe and well tolerated, with injection-site reactions being the most commonly reported adverse event. Vaccinated cancer patients exhibited a 61% immune response rate, with higher response rates in the breast and ovarian cancer patient cohorts. In keeping with the higher immune efficacy of this vaccine platform, antigen-specific responses were detected in 73% of immune responders after just one vaccination. In 83% of responders, peptide-specific T-cells were detected at two or more time points post-vaccination, with 64% of these patients showing evidence of immune persistence. Immune monitoring also demonstrated the generation of antigen-specific T-cell memory, with the ability to secrete multiple type 1 cytokines. The novel DPX formulation promotes multifunctional effector/memory responses to peptide-based tumor-associated antigens. The data support the capacity of DPX-0907 to elicit type-1 biased immune responses, warranting further clinical development of the vaccine. In this review, we discuss the rationale for developing DPX-based therapeutic cancer vaccine(s), with a focus on DPX-0907, aimed at inducing efficient anti-tumor immunity that may eventually be shown to prolong patient survival.

Survival of patients with transformed lymphoma in the rituximab era.

In the pre-rituximab era, transformation of indolent B-cell lymphoma to diffuse large B-cell lymphoma (DLBCL) was associated with an extremely poor outcome and a median post-transformation survival ranging from 1 to 2 years. We evaluated the impact of rituximab-cyclophosphamide, adriamycin, vincristine, prednisone (R-CHOP) on the survival outcomes of transformed lymphoma compared with de novo DLBCL. Between 2002 and 2010, 317 DLBCL patients who were consecutively diagnosed and treated with R-CHOP were identified at our institution. Patients with transformed lymphoma were included if they had not previously received R-CHOP. Patient characteristics, treatment, and outcome data were retrospectively collected. Sixty patients (19 %) had transformed lymphoma of which 37 (62 %) had transformed from follicular lymphoma, 50 (83 %) were chemotherapy naïve, and 58 (96 %) were rituximab naïve at the time of treatment. With a median follow-up of 31.4 months, 231 patients achieved either complete response or complete response unconfirmed (73 %) with no significant difference between de novo DLBCL (n = 192, 75 %) and the transformed group (n = 39, 65 %) (P = 0.25). Six patients (15 %) relapsed in the transformed group at a median time to relapse of 29.3 months. The 2-year and 5-year overall survivals for all patients were 82 and 72 %, respectively. The overall and progression-free survivals for transformed lymphoma and de novo DLBCL were not statistically different (P = 0.45 and P = 0.38, respectively). With R-CHOP chemotherapy, the prognosis of transformed lymphoma in patients with minimal chemotherapy exposure for indolent disease is similar to that of de novo DLBCL.

Metronomic cyclophosphamide enhances HPV16E7 peptide vaccine induced antigen-specific and cytotoxic T-cell mediated antitumor immune response.

In clinical trials, metronomic cyclophosphamide (CPA) is increasingly being combined with vaccines to reduce tumor-induced immune suppression. Previous strategies to modulate the immune system during vaccination have involved continuous administration of low dose chemotherapy, studies that have posed unique considerations for clinical trial design. Here, we evaluated metronomic CPA in combination with a peptide vaccine targeting HPV16E7 in an HPV16-induced tumor model, focusing on the cytotoxic T-cell response and timing of low dose metronomic CPA (mCPA) treatment relative to vaccination. Mice bearing C3 tumors were given metronomic CPA on alternating weeks in combination with immunization with a DepoVax vaccine containing HPV16E749-57 peptide antigen every 3 weeks. Only the combination therapy provided significant long-term control of tumor growth. The efficacy of the vaccine was uncompromised if given at the beginning or end of a cycle of metronomic CPA. Metronomic CPA had a pronounced lymphodepletive effect on the vaccine draining lymph node, yet did not reduce the development of antigen-specific CD8+ T cells induced by vaccination. This enrichment correlated with increased cytotoxic activity in the spleen and increased expression of cytotoxic gene signatures in the tumor. Immunity could be passively transferred through CD8+ T cells isolated from tumor-bearing mice treated with the combinatorial treatment regimen. A comprehensive survey of splenocytes indicated that metronomic CPA, in the absence of vaccination, induced transient lymphodepletion marked by a selective expansion of myeloid-derived suppressor cells. These results provide important insights into the multiple mechanisms of metronomic CPA induced immune modulation in the context of a peptide cancer vaccine that may be translated into more effective clinical trial designs.

First-in-man application of a novel therapeutic cancer vaccine formulation with the capacity to induce multi-functional T cell responses in ovarian, breast and prostate cancer patients.

BACKGROUND: DepoVax is a novel non-emulsion depot-forming vaccine platform with the capacity to significantly enhance the immunogenicity of peptide cancer antigens. Naturally processed HLA-A2 restricted peptides presented by breast, ovarian and prostate cancer cells were used as antigens to create a therapeutic cancer vaccine, DPX-0907. METHODS: A phase I clinical study was designed to examine the safety and immune activating potential of DPX-0907 in advanced stage breast, ovarian and prostate cancer patients. A total of 23 late stage cancer patients were recruited and were divided into two dose/volume cohorts in a three immunization protocol. RESULTS: DPX-0907 was shown to be safe with injection site reactions being the most commonly reported adverse event. All breast cancer patients (3/3), most of ovarian (5/6) and one third of prostate (3/9) cancer patients exhibited detectable immune responses, resulting in a 61% immunological response rate. Immune responses were generally observed in patients with better disease control after their last prior treatment. Antigen-specific responses were detected in 73% of immune responders (44% of evaluable patients) after the first vaccination. In 83% of immune responders (50% of evaluable patients), peptide-specific T cell responses were detected at ≥2 time points post vaccination with 64% of the responders (39% of evaluable patients) showing evidence of immune persistence. Immune monitoring also demonstrated the generation of antigen-specific T cell memory with the ability to secrete multiple Type 1 cytokines. CONCLUSIONS: The novel DepoVax formulation promotes multifunctional effector memory responses to peptide-based tumor associated antigens. The data supports the capacity of DPX-0907 to elicit Type-1 biased immune responses, warranting further clinical development of the vaccine. This study underscores the importance of applying vaccines in clinical settings in which patients are more likely to be immune competent. TRIAL REGISTRATION: ClinicalTrials.gov NCT01095848.

Increased lymphocyte infiltration in patients with head and neck cancer treated with the IRX-2 immunotherapy regimen.

Twenty-seven subjects with squamous cell cancer of the head and neck received the neoadjuvant IRX-2 immunotherapy regimen prior to surgery in a Phase 2 trial. Pretreatment tumor biopsies were compared with the primary tumor surgical specimens for lymphocyte infiltration, necrosis and fibrosis, using hematoxylin and eosin stain and immunohistochemistry in 25 subjects. Sections were examined by three pathologists. Relative to pretreatment biopsies, increases in lymphocyte infiltration (LI) were seen using H and E or immunohistochemistry. CD3+ CD4+ T cells and CD20+ B cells were primarily found in the peritumoral stroma and CD3+ CD8+ T cells and CD68+ macrophages were mainly intratumoral. LI in the surgical specimens were associated with reductions in the primary tumor size. Improved survival at 5 years was correlated with high overall LI in the tumor specimens. Neoadjuvant IRX-2 immunotherapy regimen may restore immune responsiveness presumably by mobilizing tumor infiltrating effector lymphocytes and macrophages into the tumor.

A short course of neoadjuvant IRX-2 induces changes in peripheral blood lymphocyte subsets of patients with head and neck squamous cell carcinoma.

OBJECTIVE: IRX-2, a primary cell-derived biologic with pleotropic immune activity, was shown to induce increased lymphocyte infiltrations into the tumor of patients with head and neck squamous cell cancer (HNSCC) after 10 days of neoadjuvant therapy (Berinstein et al. 2011). In the same patients enrolled in the Phase II study, peripheral blood lymphocyte subsets were monitored pre- and post-IRX-2 therapy to evaluate changes induced by IRX-2. METHODS: Absolute lymphocyte numbers were determined in whole blood using the TetraONE System. Lymphocytes were further separated on Ficoll-Hypaque gradients and evaluated by multiparameter flow cytometry. Lymphocyte numbers, including regulatory T cells (Treg) and naïve, memory and effector T cells, were compared in pre- and post-therapy specimens. RESULTS: Total lymphocyte numbers remained unchanged after IRX-2 therapy. Significant changes occurred in numbers of circulating B cells and NKT cells, which decreased following IRX-2 therapy. The frequency of circulating Treg (CD4(+)CD25(high)) remained unaltered (e.g., 6.7 ± 0.6% vs. 7.5 ± 0.8%; means ± SEM) as was the CD8(+)/Treg ratio (6.6 before and 6.7 after IRX-2 therapy). The mean absolute number of CD3(+)CD45RA(+)CCR7(+) (naïve) T cells was decreased after IRX-2 therapy but numbers of total memory (i.e., central and peripheral) and terminally differentiated T cells were unchanged. CONCLUSIONS: IRX-2-mediated reductions in B and NKT cell numbers in the blood suggest a redistribution of these cells to tissues. A decrease in naïve T cells implies their up-regulated differentiation to memory T cells. Unchanged Treg numbers after IRX-2 therapy indicate that IRX-2 does not expand this compartment, potentially benefiting anti-tumor immune responses.

Peptide Based Vaccine Approaches for Cancer-A Novel Approach Using a WT-1 Synthetic Long Peptide and the IRX-2 Immunomodulatory Regimen.

Therapeutic cancer vaccines have the potential to generate a long lasting immune response that will destroy tumor cells with specificity and safety, in contrast to many other current cancer therapies. Clinical success to date has been limited by a number of factors including choice of immunogenic cancer rejection antigens, optimization of vaccine platforms and immune adjuvants to effectively polarize the immune response, and incorporation of strategies to reverse cancer mediated immune suppression by utilization of effective adjuvant/immune modulators. WT-1 (Wilms' tumor gene 1) is a cancer antigen that is required for tumorigenesis, expressed in a high percentage of tumor cells and rarely expressed in adult normal cells. Moreover spontaneous immunity to WT-1 is seen in cancer patients and can be augmented with various therapeutic vaccine approaches. IRX-2 is an immune modulator with demonstrated preclinical and clinical pleiotropic immune activities including enhancement of the immune response to potential tumor antigens. This paper presents the rationale and preclinical data for utilizing the WT-1 tumor antigen in a novel vaccine platform consisting of a synthetic long peptide containing multiple class I and class II epitopes in combination with the IRX-2 immunomodulatory regimen to overcome immuno-suppressive pathways and enhance the anti-tumor response.

Preclinical qualification of a new multi-antigen candidate vaccine for metastatic melanoma.

New therapies are urgently required for the treatment of patients with melanoma. Here we describe the generation and preclinical evaluation of 3 new recombinant ALVAC(2) poxviruses vCP2264, vCP2291, and vCP2292 for their ability to induce the desired cellular immune responses against the encoded melanoma-associated antigens. This was done either in HLA-A2/K transgenic mice or using in vitro antigen-presentation studies. These studies demonstrated that the vaccine was able to induce HLA-A*0201-restricted T-cell responses against gp100 and NY-ESO-1, detectable directly ex vivo, in HLA-A2/K-transgenic mice. The in vitro antigen presentation studies, in the absence of appropriate animal models, demonstrated that target cells infected with the vaccine construct were lysed by MAGE-1, MAGE-3 or MART-1 peptide-specific T cells. These data indicate that ALVAC(2)-encoded melanoma-associated antigens can be properly processed and presented to induce antigen-specific cytotoxic T-cell responses. To enhance the immunogenicity of the melanoma antigens, a TRIad of COstimulatory Molecules (TRICOM) were also cloned into all 3 vectors. Increased in vitro proliferation and IFN-γ production was observed with all ALVAC(2) poxviruses encoding TRICOM, confirming the immune-enhancing effect of the ALVAC-encoded TRICOM. These studies demonstrated that all components of the vaccine were functionally active and provide a rationale for moving this candidate vaccine to the clinic.

Quantitative immunohistochemical analysis and prognostic significance of TRPS-1, a new GATA transcription factor family member, in breast cancer.

The trichorhinophalangeal syndrome 1 (TRPS-1) gene is a novel GATA transcription factor family member. Previously, using a gene expression profiling and immunohistochemistry (IHC) screen, we identified TRPS-1 as a highly prevalent gene in breast cancer (BC), expressed in >90% of estrogen receptor alpha (ERα)(+) and ERα(-) BC subtypes. TRPS-1 was also shown to be expressed in prostate cancer where it was shown to play a proapoptotic function during androgen withdrawal possibly through regulating antioxidant metabolism. The role of TRPS-1 and its prognostic significance in hormone-dependent and hormone-independent BC however is not known. In this study, we developed a new quantitative IHC (qIHC) method to further study TRPS-1 as a marker and possible prognostic indicator in BC. By using this method, a quantitative parameter for TRPS-1 expression called a quick score (QS) was derived from the measured labeling index and mean optical density after IHC and applied to a set of 152 stage II/III BC patients from 1993 to 2006 who did not receive preoperative chemotherapy. Associations between QS and tumor characteristics were evaluated using the Kruskal-Wallis test. A wide range of TRPS-1 QS was found among the sample set with higher TRPS-1 QS significantly associated with tumor ERα (p = 0.023 for QS and p = 0.028 for Allred score), progesterone receptor (p = 0.009), and GATA-3 (p < 0.0001). TRPS-1 QS was also positively associated with HER2 status (p = 0.026). Further analysis of different ductal structures in ten BC cases revealed that TRPS-1 expression was expressed at low levels in the remaining normal ducts and in areas of usual ductal hyperplasia but showed marked increase in expression in ductal carcinoma in situ and invasive carcinoma lesions in the tissue. An analysis of TRPS-1 expression in association with overall survival in the 152 stage II/III sample set also revealed that TRPS-1 QS (≥4.0) was significantly associated with improved survival (p = 0.0165). Patients with TRPS-1 QS <4 had a hazard ratio of 2 (p = 0.019) after univariate Cox proportional hazards analysis. In summary, this new qIHC approach was found to reveal critical differences in TRPS-1 expression in primary BC samples and found that it is a promising prognostic marker that should be further evaluated as a possible tumor suppressor gene facilitating improved survival in different subtypes of BC.

Strategies to enhance the therapeutic activity of cancer vaccines: using melanoma as a model.

Although there has been initial success with some types of immunotherapy, such as adoptive cellular therapy and monoclonal antibody therapy for cancer, the experience with therapeutic cancer vaccines has been much less encouraging. Almost all randomized phase III trials testing therapeutic cancer vaccines have failed to meet their end points. There are several potential explanations for this, ranging from factors related to the clinical trial design and the vaccine itself. Perhaps the most important are host-related factors. Specifically, progression and metastases of many cancers are associated with induction of multiple cancer-specific immune-inhibitory pathways. These inhibitory pathways include induction of T-cell anergy through dendritic cell dysfunction, release of immunosuppressive cytokines, T-cell exhaustion through inhibitory T-cell signaling and T regulatory cell-mediated tumor-specific immune suppression. All of these pathways have been shown to be operational in patients with melanoma. To enhance the activity of therapeutic cancer vaccines, these immunosupressive pathways need to be addressed and reversed. A number of new immunomodulatory reagents that are able to interfere with some of these pathways are now being assessed in the clinic. Sanofi Pasteur designed a clinical trial in patients with advanced or metastatic melanoma that is intended to both induce tumor-specific T-cell responses and modulate or reverse some of the immune suppression pathways that the melanoma has induced. To accomplish this, the recently optimized ALVAC melanoma multi-antigen vaccine is administered with high doses of IFN-alpha. Clinical trial parameters have also been optimized to enhance the likelihood of inducing and documenting antitumor activity. Success with other therapeutic cancer vaccine approaches will likely require similar approaches in which promising immunogenic vaccines are integrated with biologically and clinically active immunomodulatory reagents.