Next generation of immune checkpoint therapy in cancer: new developments and challenges

Immune checkpoints consist of inhibitory and stimulatory pathways that maintain self-tolerance and assist with immune response. In cancer, immune checkpoint pathways are often activated to inhibit the nascent anti-tumor immune response. Immune checkpoint therapies act by blocking or stimulating these pathways and enhance the body's immunological activity against tumors. Cytotoxic T lymphocyte-associated molecule-4 (CTLA-4), programmed cell death receptor-1 (PD-1), and programmed cell death ligand-1(PD-L1) are the most widely studied and recognized inhibitory checkpoint pathways. Drugs blocking these pathways are currently utilized for a wide variety of malignancies and have demonstrated durable clinical activities in a subset of cancer patients. This approach is rapidly extending beyond CTLA-4 and PD-1/PD-L1. New inhibitory pathways are under investigation, and drugs blocking LAG-3, TIM-3, TIGIT, VISTA, or B7/H3 are being investigated. Furthermore, agonists of stimulatory checkpoint pathways such as OX40, ICOS, GITR, 4-1BB, CD40, or molecules targeting tumor microenvironment components like IDO or TLR are under investigation. In this article, we have provided a comprehensive review of immune checkpoint pathways involved in cancer immunotherapy, and discuss their mechanisms and the therapeutic interventions currently under investigation in phase I/II clinical trials. We also reviewed the limitations, toxicities, and challenges and outline the possible future research directions.

Phase I/II trial of pembrolizumab in combination with binimetinib in unresectable locally advanced or metastatic triple negative breast cancer

TPS17

Background: Emerging studies suggest that breast cancer, particularly triple negative breast cancer (TNBC), may be sensitive to immunotherapy. However, the response rate of single agent immune checkpoint blockade agent in TNBC is rather low. Previous genomic study in residual tumor after neoadjuvant chemotherapy showed inverse correlations between MEK activation signature and the amount of tumor infiltrating lymphocytes (TILs) in residual disease samples as well as poor outcome. Preclinical study also showed that the combination of MEK inhibitor and anti-PD-L1 antibody in mouse model can eradicate TNBC tumors. Methods: This is a single arm, Phase I/II trial of Pembrolizumab (P) in combination with Binimetinib (B) in patients with unresectable locally advanced or metastatic TNBC. This trial is currently opened for accrual at Mayo Clinic in Florida and Minnesota. Patients with TNBC defined as ER ≤ 10% and PR ≤ 10% who received ≤ 3 prior lines with measurable disease will be enrolled. The primary objective of the Phase I part is to determine the maximum tolerated dose of B in combination with P and for the Phase II part is objective response rate (ORR) by RECIST criteria. The secondary endpoints include ORR by irRECIST, progression free survival, and overall survival. The total sample size is 15-38 patients with 6-12 patients in Phase I with 2 dose levels and 9-26 patients in Phase II. Simon’s Two-Stage Optimal Design is used to test the null hypothesis that this two-drug combination has an ORR of at most 15% vs. the alternative hypothesis that it has an ORR of at least 35%. Patients will receive single agent B for 2 weeks prior to starting P. A mandatory biopsy will be performed before starting B and an optional biopsy will be performed after 2 weeks of B. Tumor tissue will be evaluated for the amount and phenotypes of TILs, PD-L1 expression, and gene expression analysis using PanCancer Immune Profiling Panel, and PDJ amplification. Peripheral blood will be evaluated for circulating immunoregulatory cells, cytokine profiling, circulating tumor cells (CTCs), as well as p-ERK and PD-L1 expression on CTCs. Clinical trial information: NCT03106415.

Cancer immunotherapy beyond immune checkpoint inhibitors

Malignant cells have the capacity to rapidly grow exponentially and spread in part by suppressing, evading, and exploiting the host immune system. Immunotherapy is a form of oncologic treatment directed towards enhancing the host immune system against cancer. In recent years, manipulation of immune checkpoints or pathways has emerged as an important and effective form of immunotherapy. Agents that target cytotoxic T lymphocyte-associated molecule-4 (CTLA-4), programmed cell death receptor-1 (PD-1), and programmed cell death ligand-1 (PD-L1) are the most widely studied and recognized. Immunotherapy, however, extends beyond immune checkpoint therapy by using new molecules such as chimeric monoclonal antibodies and antibody drug conjugates that target malignant cells and promote their destruction. Genetically modified T cells expressing chimeric antigen receptors are able to recognize specific antigens on cancer cells and subsequently activate the immune system. Native or genetically modified viruses with oncolytic activity are of great interest as, besides destroying malignant cells, they can increase anti-tumor activity in response to the release of new antigens and danger signals as a result of infection and tumor cell lysis. Vaccines are also being explored, either in the form of autologous or allogenic tumor peptide antigens, genetically modified dendritic cells that express tumor peptides, or even in the use of RNA, DNA, bacteria, or virus as vectors of specific tumor markers. Most of these agents are yet under development, but they promise to be important options to boost the host immune system to control and eliminate malignancy. In this review, we have provided detailed discussion of different forms of immunotherapy agents other than checkpoint-modifying drugs. The specific focus of this manuscript is to include first-in-human phase I and phase I/II clinical trials intended to allow the identification of those drugs that most likely will continue to develop and possibly join the immunotherapeutic arsenal in a near future.

Macrophagic "Crown-like Structures" Are Associated with an Increased Risk of Breast Cancer in Benign Breast Disease

In breast adipose tissue, macrophages that encircle damaged adipocytes form "crown-like structures of breast" (CLS-B). Although CLS-B have been associated with breast cancer, their role in benign breast disease (BBD) and early carcinogenesis is not understood. We evaluated breast biopsies from three age-matched groups (n = 86 each, mean age 55 years), including normal tissue donors of the Susan G. Komen for the Cure Tissue Bank (KTB), and subjects in the Mayo Clinic Benign Breast Disease Cohort who developed cancer (BBD cases) or did not develop cancer (BBD controls, median follow-up 14 years). Biopsies were classified into histologic categories, and CD68-immunostained tissue sections were evaluated for the frequency and density of CLS-B. Our data demonstrate that CLS-B are associated with BBD: CLS-B-positive samples were significantly less frequent among KTB biopsies (3/86, 3.5%) than BBD controls (16/86 = 18.6%, P = 0.01) and BBD cases (21/86 = 24%, P = 0.002). CLS-B were strongly associated with body mass index (BMI); BMI < 25: 7% CLS-B positive, BMI 25-29: 13%, and BMI ≥ 30: 29% (P = 0.0005). Among BBD biopsies, a high CLS-B count [>5 CLS-B/sample: 10.5% (BBD cases) vs 4.7% (BBD controls), P = 0.007] conferred a breast cancer OR of 6.8 (95% CI, 1.4-32.4), P = 0.02, after adjusting for adipose tissue area (cm²), histologic impression, and BMI. As high CLS-B densities are independently associated with an increased breast cancer risk, they may be a promising histologic marker of breast cancer risk in BBD. Cancer Prev Res; 11(2); 113-9. ©2017 AACR.

CD56+ immune cell infiltration and MICA are decreased in breast lobules with fibrocystic changes

Purpose

While the role of natural killer (NK) cells in breast cancer therapy has been investigated, little information is known about NK cell function and presence in nonmalignant and premalignant breast tissue. Here, we investigate and quantify NK cell marker CD56 and activating ligand MICA in breast tissue with benign breast disease.

Methods

Serial tissue sections from 88 subjects, 44 with benign breast disease (BBD) who remained cancer-free, and 44 with BBD who later developed cancer, were stained with H&E, anti-MICA, and anti-CD56. Up to ten representative lobules were identified on each section. Using digital image analysis, MICA and CD56 densities were determined for each lobule, reported as percent of pixels in the lobule that registered as stained by each antibody. Analyses were performed on a per-subject and per-lobule basis.

Results

Per-subject multivariate analyses showed associations of CD56 and MICA with age: CD56 was increased in older subjects (p = 0.03), while MICA was increased in younger subjects (p = 0.005). Per-lobule analyses showed that CD56 and MICA levels were both decreased in lobules with fibrocystic change, with median levels of CD56 and MICA staining, respectively, at 0.31 and 7.0% in fibrocystic lobules compared to 0.76 and 12.2% in lobules without fibrocystic change (p < 0.001 for each). Among fibrocystic lobules, proliferative/atypical lobules showed significantly lower expression compared to nonproliferative lobules for MICA (p = 0.02) but not for CD56 (p = 0.80).

Conclusion

Levels of CD56+ NK cells and activating ligand MICA were decreased in breast lobules with fibrocystic change, and MICA levels showed a significant stepwise decrease with increasing histopathologic abnormality. MICA levels were also significantly decreased in older subjects, who generally have higher risk of developing cancer. These findings advance a model in which MICA promotes cytotoxic activity in CD56+ NK cells to protect against tumorigenesis in breast lobules, and suggest further research is warranted.

Electronic supplementary material

The online version of this article (10.1007/s10549-017-4558-0) contains supplementary material, which is available to authorized users.

IL10 Release upon PD-1 Blockade Sustains Immunosuppression in Ovarian Cancer

Ligation of programmed cell death-1 (PD-1) in the tumor microenvironment is known to inhibit effective adaptive antitumor immunity. Blockade of PD-1 in humans has resulted in impressive, durable regression responses in select tumor types. However, durable responses have been elusive in ovarian cancer patients. PD-1 was recently shown to be expressed on and thereby impair the functions of tumor-infiltrating murine and human myeloid dendritic cells (TIDC) in ovarian cancer. In the present work, we characterize the regulation of PD-1 expression and the effects of PD-1 blockade on TIDC. Treatment of TIDC and bone marrow-derived dendritic cells (DC) with IL10 led to increased PD-1 expression. Both groups of DCs also responded to PD-1 blockade by increasing production of IL10. Similarly, treatment of ovarian tumor-bearing mice with PD-1 blocking antibody resulted in an increase in IL10 levels in both serum and ascites. While PD-1 blockade or IL10 neutralization as monotherapies were inefficient, combination of these two led to improved survival and delayed tumor growth; this was accompanied by augmented antitumor T- and B-cell responses and decreased infiltration of immunosuppressive MDSC. Taken together, our findings implicate compensatory release of IL10 as one of the adaptive resistance mechanisms that undermine the efficacy of anti-PD-1 (or anti-PD-L1) monotherapies and prompt further studies aimed at identifying such resistance mechanisms. Cancer Res; 77(23); 6667-78. ©2017 AACR.

Multivalent bi-specific nanobioconjugate engager for targeted cancer immunotherapy

Tumour-targeted immunotherapy offers the unique advantage of specific tumouricidal effects with reduced immune-associated toxicity. However, existing platforms suffer from low potency, inability to generate long-term immune memory and decreased activities against tumour-cell subpopulations with low targeting receptor levels. Here we adopted a modular design approach that uses colloidal nanoparticles as substrates to create a multivalent bi-specific nanobioconjugate engager (mBiNE) to promote selective, immune-mediated eradication of cancer cells. By simultaneously targeting the human epidermal growth factor receptor 2 (HER2) expressed by cancer cells and pro-phagocytosis signalling mediated by calreticulin, the mBiNE stimulated HER2-targeted phagocytosis and produced durable antitumour immune responses against HER2-expressing tumours. Interestingly, although the initial immune activation mediated by the mBiNE was receptor dependent, the subsequent antitumour immunity also generated protective effects against tumour-cell populations that lacked the HER2 receptor. Thus, the mBiNE represents a new targeted, nanomaterial-immunotherapy platform to stimulate innate and adaptive immunity and promote a universal antitumour response.

Abstract 1682: Correlation of immune co-stimulatory molecule OX40 and outcome in trastuzumab treated HER2-positive breast cancer patients in the NCCTG-N9831

Background: Trastuzumab (H), a monoclonal antibody against HER2, has revolutionized the treatment for HER2-positive breast cancer. Besides inhibiting downstream signaling of HER2, several studies showed that H also exerts its anti-tumor activity via immune-related mechanisms. While H is quite effective in preventing recurrence, significant numbers of patients still develop recurrence despite adjuvant H-based chemotherapy. In this study, we analyzed immune-related genes that were associated with poor outcome in N9831.

Methods: NanoStringTM technology was used to quantify mRNA of immune-related genes in baseline samples from 1,280 patients in N9831. In N9831, patients in arm A were treated with chemotherapy alone (AC-T), arm B received chemotherapy followed by sequential H (AC-T-H), and arm C received H concurrently with chemotherapy (AC-TH). Cox proportional hazard ratio (HR) was used to determine the association of each immune-related gene with recurrence free survival (RFS). Different immune subset signatures, including CD45, CD8, cytotoxic-cells, and T-cells were analyzed using algorithms developed by NanoString.

Results: With the median follow up of 10.6 years, we identified a total 77 genes that were associated with improved outcome in arm C. Among these 77 genes, there were 20 tumor necrosis factor (TNF)-related genes. Of those, only OX40 (TNFRSF4) and its ligand TNFSF4 have interaction p &lt; 0.10. Interestingly, we found uneven distribution of OX40 expression in the N9831 specimens. Approximately, 9.5% of HER2-positive breast cancer expressed OX40 at distinctly low level. Low expression of OX40 was significantly associated with HR positivity (OX40 low 61% vs. OX40 high 51%, p 0.003) and larger tumor size but not patients’ age, tumor grade, and lymph node status. Low expression of OX40 was significantly associated with low mTIL-CD45, CD8, cytotoxic-cells, and T-cells immune signature scores. Tumors with low OX40 expression had significantly lower levels of CTLA4 (p 9.11e-71) and PD-L1 expressions (p 2.49e-92). Low expression of OX40 is associated with poorer outcome among patients treated with H in both sequential (HR 0.88, 95% CI 0.79-0.98, p 0.022) and concurrent arms (HR 0.86, 95%CI 0.76-0.98, p 0.027) but not in chemotherapy only arm (HR 0.9, 95%CI 0.90-1.09, p 0.8). Similar findings were observed with its ligand TNFSF4 in arm A (HR 1.02, 95%CI 0.92-1.15, p 0.68), arm B (HR 0.87, 95%CI 0.76-0.99, p 0.04), and arm C (HR 0.81, 95%CI 0.68-0.95, p 0.01).

Conclusion: Our study suggests that pre-existing expression of OX40 and its ligand TNFSF4 are prognostic and may also be predictive of adjuvant H benefit. Patients with distinctly low level of OX40 had poor outcome despite adjuvant H-based adjuvant chemotherapy. Our study provides a rationale to further evaluate the strategy to increase immune activation to improve outcome in this group of patients.

Citation Format: Saranya Chumsri, Daniel J. Serie, Afshin Mashadi-Hossein, Sarah Warren, Alvaro Moreno-Aspitia, Geraldo Colon-Otero, Keith L. Knutson, Edith A. Perez, E. Aubrey Thompson. Correlation of immune co-stimulatory molecule OX40 and outcome in trastuzumab treated HER2-positive breast cancer patients in the NCCTG-N9831 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1682. doi:10.1158/1538-7445.AM2017-1682

Effects of age, immune landscape, and response to trastuzumab (H) in HER-2 positive (HER2+) breast cancer in NCCTG (Alliance)-N9831

530

Background: Therapeutic efficacy of H involves activation of the immune system.Age-dependent progressive deterioration of the immune response is referred as immunosenescence. In HER2+ breast cancer, the effects of aging and the ability of H to activate endogenous anti-tumor immunity is unknown. A previous report from HERA trial showed no significant increase in risk of early recurrence with age (≤ or > 40). We evaluated the long-term outcome of HER2+ patients (pt) related to age and immune landscape. Methods: 1,392 pt from N9831 trial were evaluated. Stromal tumor infiltrating lymphocytes (sTIL) were evaluated in H&E slides. Lymphocyte predominant breast cancer (LPBC) was defined as sTIL ≥ 50%. Molecular TIL (mTIL) and immune subset signatures were evaluated using NanoString research CodeSets. Cox proportional hazard ratio (HR) was used for analysis. Results: There were 1,111 (79.8%) pt > 40 years old (yo) and 281 (20.2%) pt ≤ 40 yo. Younger age was significantly associated with hormone receptor positivity (p 0.00011) and luminal B subtype (p 0.011). With a median follow up of 10.6 years, there was no significant difference in long-term outcome among pt ≤ 40 vs. > 40 yo who received H (HR = 0.88 (0.62-1.24), p = 0.45). Similar findings were observed when age was dichotomized at 50 and 60 yo. While there was no association between sTIL and age, a small but significant increase in mTIL CD45 expression with age (p 0.003) was observed. Similar small increases in cytotoxic cell (p 0.007) and T cell (p 0.015) immune scores were also observed with increasing age. Among pt who received chemotherapy alone, pt > 40 yo with LPBC (n 55) had excellent outcome with 92.4% recurrence free survival (RFS) at 10 years. However, there was no significant difference in RFS among pt ≤ 40 yo with or without LPBC. Conclusions: Among pt treated with H, there was no significant difference in outcome related to age. In contrast to a decline expected from immunosenescence, we observed small but significant increases in mTIL signatures for total lymphocytes, cytotoxic, and T cell subsets. Among patients who received chemotherapy alone, our data suggested that pt > 40 yo with LPBC had excellent prognosis, compared to pt > 40 yo without LPBC.

Abstract ES4-1: Basic science of immunotherapy

While it remains unclear whether the immune system naturally evolved to prevent cancer, it is clear that many of its constituent cells and factors can greatly influence the clinical course of the disease in many different cancers, including breast cancer. Generally speaking, the immune system is a double edged sword and produces a broad array of both pro-tumor and anti-tumor factors. Of those which demonstrate anti-tumor activity, antigen-specific T cells (including both cytotoxic and helper T cells) are the most important as several studies have now shown that increased T cell infiltration is generally, and markedly, protective. More recent evidence also suggests that B cells can also be protective, particularly when producing tumor-specific antibodies or associated with intratumoral tertiary lymphoid structures. Thus, newer therapeutics being developed in academia and industry are being designed to directly augment adaptive immunity. The methods to manipulate the numbers of lymphocytes is growing and includes direct clonal expansion approaches such as vaccination and adoptive T cell therapy as well as more indirect methods that modulate cell intrinsic regulatory mechanisms (e.g. checkpoint and co-stimulatory pathways). In contrast, the pro-tumor activity of the immune system is largely mediated by the myeloid compartment of the immune system. While normal myeloid cells are not generally pro-tumorigenic, most tumors impair proper myeloid differentiation inducing intratumoral and systemic accumulation of defective myeloid cells which have profound tumor-promoting activity. This tumor-promoting activity of myeloid cells is mediated either through direct tumor growth-promoting activity (e.g. growth and angiogenic factors) or through blockade of adaptive immune response. Mechanisms by myeloid cells promote tumor growth appear to be diversified and are now only recently becoming understood, but nonetheless represent unique targets for therapeutic manipulation either alone in combination with other therapeutic modalities (e.g. checkpoint blockade). The basic underpinnings of tumor immunology are being rapidly identified and applied clinically to treat a variety of cancers and more recently breast cancer. This educational lecture will be a general overview of tumor immunology focusing on recent basic and therapeutic advances, highlighting those relevant to the field of breast cancer.

Citation Format: Knutson KL. Basic science of immunotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr ES4-1.

Cytokine and neuropeptide levels are associated with pain relief in patients with chronically painful total knee arthroplasty: a pilot study

Background

There are few studies with an assessment of the levels of cytokines or neuropeptides as correlates of pain and pain relief in patients with painful joint diseases. Our objective was to assess whether improvements from baseline to 2-months in serum cytokine, chemokine and substance P levels were associated with clinically meaningful pain relief at 2-months post-injection in patients with painful total knee arthroplasty (TKA).

Methods

Using data from randomized trial of 60 TKAs, we assessed the association of change in cytokine/chemokine/Substance P levels with primary study outcome, clinically important improvement in Western Ontario McMaster Osteoarthritis Index (WOMAC) pain subscale at 2-months post-injection using Student’s t-tests and Spearman’s correlation coefficient (non-parametric). Patients were categorized as pain responders (20-point reduction or more on 0-100 WOMAC pain) vs. pain non-responders. Sensitivity analysis used 0–10 daytime pain numeric rating scale (NRS) instead of WOMAC pain subscale.

Results

In a pilot study, compared to non-responders (n = 23) on WOMAC pain scale at 2-months, pain responders (n = 12) had significantly greater increase in serum levels of IL-7, IL-10, IL-12, eotaxin, interferon gamma and TNF-α from baseline to 2-months post-injection (p < 0.05 for all). Change in several cytokine/chemokine and substance P levels from pre-injection to 2-month follow-up correlated significantly with change in WOMAC pain with correlation coefficients ranging −0.37 to −0.51: IL-2, IL-7, IL-8, IL-9, IL-16, IL-12p, GCSF, IFN gamma, IP-10, MCP, MIP1b, TNF-α and VEGF (n = 35). Sensitivity analysis showed that substance P decreased significantly more from baseline to 2-months in the pain responders (0.54 ± 0.53; n = 10) than in the pain non-responders (0.48 ± 1.18; n = 9; p = 0.023) and that this change in serum substance P correlated significantly with change in daytime NRS pain, correlation coefficient was 0.53 (p = 0.021; n = 19). Findings should be interpreted with caution, since cytokine analyses were performed for a sub-group of the entire trial population.

Conclusion

Serum cytokine, chemokine and Substance P levels correlated with pain response in patients with painful TKA after an intra-articular injection in a randomized trial.

Assessment of variation in immunosuppressive pathway genes reveals TGFBR2 to be associated with risk of clear cell ovarian cancer

BACKGROUND

Regulatory T (Treg) cells, a subset of CD4+ T lymphocytes, are mediators of immunosuppression in cancer, and, thus, variants in genes encoding Treg cell immune molecules could be associated with ovarian cancer.

METHODS

In a population of 15,596 epithelial ovarian cancer (EOC) cases and 23,236 controls, we measured genetic associations of 1,351 SNPs in Treg cell pathway genes with odds of ovarian cancer and tested pathway and gene-level associations, overall and by histotype, for the 25 genes, using the admixture likelihood (AML) method. The most significant single SNP associations were tested for correlation with expression levels in 44 ovarian cancer patients.

RESULTS

The most significant global associations for all genes in the pathway were seen in endometrioid ( p = 0.082) and clear cell ( p = 0.083), with the most significant gene level association seen with TGFBR2 ( p = 0.001) and clear cell EOC. Gene associations with histotypes at p < 0.05 included: IL12 ( p = 0.005 and p = 0.008, serous and high-grade serous, respectively), IL8RA ( p = 0.035, endometrioid and mucinous), LGALS1 ( p = 0.03, mucinous), STAT5B ( p = 0.022, clear cell), TGFBR1 ( p = 0.021 endometrioid) and TGFBR2 ( p = 0.017 and p = 0.025, endometrioid and mucinous, respectively).

CONCLUSIONS

Common inherited gene variation in Treg cell pathways shows some evidence of germline genetic contribution to odds of EOC that varies by histologic subtype and may be associated with mRNA expression of immune-complex receptor in EOC patients.

The Microbiome of Aseptically Collected Human Breast Tissue in Benign and Malignant Disease

Globally breast cancer is the leading cause of cancer death among women. The breast consists of epithelium, stroma and a mucosal immune system that make up a complex microenvironment. Growing awareness of the role of microbes in the microenvironment recently has led to a series of findings important for human health. The microbiome has been implicated in cancer development and progression at a variety of body sites including stomach, colon, liver, lung, and skin. In this study, we assessed breast tissue microbial signatures in intraoperatively obtained samples using 16S rDNA hypervariable tag sequencing. Our results indicate a distinct breast tissue microbiome that is different from the microbiota of breast skin tissue, breast skin swabs, and buccal swabs. Furthermore, we identify distinct microbial communities in breast tissues from women with cancer as compared to women with benign breast disease. Malignancy correlated with enrichment in taxa of lower abundance including the genera Fusobacterium, Atopobium, Gluconacetobacter, Hydrogenophaga and Lactobacillus. This work confirms the existence of a distinct breast microbiome and differences between the breast tissue microbiome in benign and malignant disease. These data provide a foundation for future investigation on the role of the breast microbiome in breast carcinogenesis and breast cancer prevention.

Improved Survival of HER2+ Breast Cancer Patients Treated with Trastuzumab and Chemotherapy Is Associated with Host Antibody Immunity against the HER2 Intracellular Domain

The addition of trastuzumab to chemotherapy extends survival among patients with HER2(+) breast cancer. Prior work showed that trastuzumab and chemotherapy augments HER2 extracellular domain (ECD)-specific antibodies. The current study investigated whether combination therapy induced immune responses beyond HER2-ECD and, importantly, whether those immune responses were associated with survival. Pretreatment and posttreatment sera were obtained from 48 women with metastatic HER2(+) breast cancer on NCCTG (now Alliance for Clinical Trials in Oncology) studies, N0337 and N983252. IgG to HER2 intracellular domain (ICD), HER2-ECD, p53, IGFBP2, CEA, and tetanus toxoid were examined. Sera from 25 age-matched controls and 26 surgically resected HER2(+) patients were also examined. Prior to therapy, some patients with metastatic disease had elevated antibodies to IGFBP2, p53, HER2-ICD, HER2-ECD, and CEA, but not to tetanus toxin, relative to controls and surgically resected patients. Treatment augmented antibody responses to HER2-ICD in 69% of metastatic patients, which was highly associated with improved progression-free survival (PFS; HR = 0.5, P = 0.0042) and overall survival (OS; HR = 0.7, P = 0.038). Augmented antibody responses to HER2-ICD also correlated (P = 0.03) with increased antibody responses to CEA, IGFBP2, and p53, indicating that treatment induces epitope spreading. Paradoxically, patients who already had high preexisting immunity to HER2-ICD did not respond to therapy with increased antibodies to HER2-ICD and demonstrated poorer PFS (HR = 1.6, P < 0.0001) and OS (HR = 1.4, P = 0.0006). Overall, the findings further demonstrate the importance of the adaptive immune system in the efficacy of trastuzumab-containing regimens. Cancer Res; 76(13); 3702-10. ©2016 AACR.

Abstract P2-11-02: Robust generation of T cell immunity to HER2 in HER2+ breast cancer patients with a degenerate subdominant HLA-DR epitope vaccine

Background: Recent studies have indicated that vaccination can protect against cancer development. One key aspect of developing vaccines is circumventing peripheral tolerance by identifying subdominant epitopes that are unique to the deregulated tumor microenvironment. While existing subdominant epitope vaccines are showing efficacy in preventing cancer, these vaccines are applicable only for subsets of patients with specific HLA subtypes. Therefore, we recently developed a degenerate HER2 subdominant epitope-based vaccine that should be useful in approximately 85% of all patients. The vaccine consists of a pool of four HLA-DR-restricted 15-amino acid epitopes (p59, p88, p422, and p885) that are naturally processed and are designed to elicit helper T cell immunity, the cornerstone of immune surveillance. Here we present Phase I trial results of this multi-peptide HER2 vaccine.

Methods: Eligible women had HER2+ breast cancer (Stages II-III) and had completed standard treatment (i.e. surgery, chemotherapy, and trastuzumab) at least 90 days prior to enrollment and were rendered disease free. Vaccine included the above epitope pool along with adjuvant GM-CSF. Patients were vaccinated six times over six months and were monitored for toxicity at each visit. Peripheral blood samples were collected for immune responses evaluating for T cell and antibody immunity. Endpoints were safety and immunogenicity leading to the development CD4 helper T cells that recognized naturally-processed HER2.

Results: Twenty-two subjects (age 33 to 69 years) were enrolled. At the present analysis, 21 have completed all 6 vaccination cycles; one patient withdrew after developing a grade 1 injection site reaction during the first vaccination cycle. Twenty patients have had LVEF measured after vaccination; only 2 patients had an LVEF drop of 10% or more but remained in the normal LEVF range. One severe toxicity was reported: a grade 3 INR increase considered unrelated to treatment. Mild to moderate (grade 1-2) toxicities included injection site reactions, fatigue, and white blood cell count decreases. All patients were alive at analysis and only one experienced a recurrence (median follow-up 507 days, range 22 – 844). Twenty patients have had immune response assessments. Vaccine induced T cell immunity was observed in 94% of patients to p59, in 94% of patients to p88, in 82% of patients to p422, and in 74% of patients to p885. Importantly, T cell immunity to naturally processed HER2 proteins occurred in 94% of patients. The mean number of T cells specific for each peptide, post vaccination, ranged from 349–528 T cells per million peripheral blood mononuclear cells (PBMCs). The mean number of T cells specific for whole HER2 protein was 783 T cells per million PBMCs compared to a mean of 898 T cells/million PBMCs specific for the foreign tetanus toxin. In contrast to T cell responses, modestly increased antibody immunity to HER2 occurred in 35% of patients, consistent with the T cell-inducing design of the vaccine.

Conclusion: Our results show that it is possible to develop vaccines with broad HLA coverage that circumvent natural tolerance and induce tumor antigen-specific immunity in the vast majority of patients.

Citation Format: Knutson KL, Kalli KR, Block MS, Hobday TJ, Padley DJ, Erskine CL, Dockter T, Suman VJ, Wilson G, Degnim AC. Robust generation of T cell immunity to HER2 in HER2+ breast cancer patients with a degenerate subdominant HLA-DR epitope vaccine. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P2-11-02.

Combinatorial Immunoprofiling in Latent Tuberculosis Infection. Toward Better Risk Stratification

RATIONALE

Most immunocompetent patients diagnosed with latent tuberculosis infection (LTBI) will not progress to tuberculosis (TB) reactivation. However, current diagnostic tools cannot reliably distinguish nonprogressing from progressing patients a priori, and thus LTBI therapy must be prescribed with suboptimal patient specificity. We hypothesized that LTBI diagnostics could be improved by generating immunomarker profiles capable of categorizing distinct patient subsets by a combinatorial immunoassay approach.

OBJECTIVES

A combinatorial immunoassay analysis was applied to identify potential immunomarker combinations that distinguish among unexposed subjects, untreated patients with LTBI, and treated patients with LTBI and to differentiate risk of reactivation.

METHODS

IFN-γ release assay (IGRA) was combined with a flow cytometric assay that detects induction of CD25(+)CD134(+) coexpression on TB antigen-stimulated T cells from peripheral blood. The combinatorial immunoassay analysis was based on receiver operating characteristic curves, technical cut-offs, 95% bivariate normal density ellipse prediction, and statistical analysis. Risk of reactivation was estimated with a prediction formula.

MEASUREMENTS AND MAIN RESULTS

Sixty-five out of 150 subjects were included. The combinatorial immunoassay approach identified at least four different T-cell subsets. The representation of these immune phenotypes was more heterogeneous in untreated patients with LTBI than in treated patients with LTBI or unexposed groups. Patients with IGRA(+) CD4(+)CD25(+)CD134(+) T-cell phenotypes had the highest estimated reactivation risk (4.11 ± 2.11%).

CONCLUSIONS

These findings suggest that immune phenotypes defined by combinatorial assays may potentially have a role in identifying those at risk of developing TB; this potential role is supported by risk of reactivation modeling. Prospective studies will be needed to test this novel approach.

PD-1 Blunts the Function of Ovarian Tumor-Infiltrating Dendritic Cells by Inactivating NF-κB

The PD-1:PD-L1 immune signaling axis mediates suppression of T-cell-dependent tumor immunity. PD-1 expression was recently found to be upregulated on tumor-infiltrating murine (CD11c(+)CD11b(+)CD8(-)CD209a(+)) and human (CD1c(+)CD19(-)) myeloid dendritic cells (TIDC), an innate immune cell type also implicated in immune escape. However, there is little knowledge concerning how PD-1 regulates innate immune cells. In this study, we examined the role of PD-1 in TIDCs derived from mice bearing ovarian tumors. Similar to lymphocytes, TIDC expression of PD-1 was associated with expression of the adapter protein SHP-2, which signals to NF-κB; however, in contrast to its role in lymphocytes, we found that expression of PD-1 in TIDC tonically paralyzed NF-κB activation. Further mechanistic investigations showed that PD-1 blocked NF-κB-dependent cytokine release in a SHP-2-dependent manner. Conversely, inhibition of NF-κB-mediated antigen presentation by PD-1 occurred independently of SHP-2. Collectively, our findings revealed that PD-1 acts in a distinct manner in innate immune cells compared with adaptive immune cells, prompting further investigations of the signaling pathways controlled by this central mediator of immune escape in cancer.

Abstract B34: CD56+ immune cell infiltration is decreased in benign breast lobules with fibrocystic changes

Introduction: CD56+ lymphocytes (a defining marker of natural killer cells) have a predominantly cytotoxic phenotype and a hypothetical role in breast tumor immunosurveillance. Here we investigate whether CD56+ staining density varies in nonmalignant breast lobules according to confirmed breast cancer risk factors- age, and histologic features of fibrocystic change and lobular involution.

Methods: Archived breast tissue samples were obtained from 94 women with benign breast disease (BBD). The sample set was selected as a nested case-control study (47 cases, 47 controls) from within a large BBD cohort; cases were those who developed breast cancer subsequent to their benign breast biopsy; controls were matched to cases on age at biopsy, year of biopsy, and length of breast cancer free follow-up at least as long as the time-to-cancer in the matched case. Up to 10 representative lobules in each sample were characterized by H&E for fibrocystic changes and the degree of epithelial proliferation (normal, nonproliferative, proliferative, atypia) and for degree of lobular involution (none, partial, complete). Consecutive sections were immunostained for CD56 and hematoxylin. Using digital image analysis, CD56 staining was quantified on a per lobule basis by pixel ratio (PR) (positive stain:total lobule). Statistical analysis was performed using linear mixed effects regression on the rank transformed density to account for correlations among multiple lobules from the same patient in assessing the association of density with lobule characteristics and using conditional logistic regression for association with case-control status.

Results: Among 94 women (median age 52, range 35-73), 876 lobules were evaluated: 431 in BBD cases and 445 in BBD controls. Overall, 391 lobules (45%) were normal and the remaining 485 (55%) demonstrated fibrocystic changes. Among fibrocystic lobules, 247 (51%) had nonproliferative changes, 218 (45%) had epithelial proliferation, and 20 (4%) had atypical hyperplasia. Among normal lobules, 61 (16%) had no involution, 139 (36%) had partial involution, and 191 (49%) had complete involution. The vast majority of lobules (861/876, 98%) demonstrated presence of CD56+ cells, while only 15 of 876 lobules in 11 patients had zero CD56+ cells [7 cases (15%) versus 4 controls (8.5%) OR 1.75, p = 0.37].

The median CD56+ PR was 0.55% overall. Fibrocystic lobules as a group showed significantly lower median CD56+ PR compared to normal lobules (0.37% vs 0.85%, p &lt; 0.0001). Among subcategories of fibrocystic lobules, the median CD56+ PR was lower in proliferative lobules (0.29%) compared to non-proliferative (0.42%), but this difference was not statistically significant (p = 0.55). Older women (age &gt; 55) showed the highest CD56+ PR (median of 0.92%), as compared to 0.38% in women 45-55 (p=0.02), and 0.52% in women age &lt;45 (p = 0.26). Among normal lobules, median CD56+ PR was similar between lobules with no involution (0.55%) and partial involution (0.52%) but was considerably higher among lobules with complete involution (1.3%, p = 0.09 and p = 0.05, respectively). In a multivariable model, CD56+ PR differences between fibrocystic and normal lobules remained significant (p = 0.0002) and also remained significant between age groups of &gt; 55 and 45-55 (p = 0.02), while involution was non-significant. Median CD56+ PR was lower in cases (0.43%) compared to controls (0.72%), but this was not statistically significant (p=0.19) in our sample of 47 case-control pairs.

Conclusions: Breast lobules with fibrocystic changes show less CD56+ cells, raising a question of possible immune suppression induced by early epithelial abnormalities. These findings encourage further investigation to improve understanding of the immune microenvironment in premalignant breast tissues.

Citation Format: Rushin D. Brahmbhatt, Daniel Kerekes, Tanya L. Hoskin, Alvaro Pena, Daniel W. Visscher, Melody L. Stallings-Mann, Derek C. Radisky, Linda M. Murphy, Vernon Shane Pankratz, Keith L. Knutson, Marlene Frost, Amy C. Degnim. CD56+ immune cell infiltration is decreased in benign breast lobules with fibrocystic changes. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr B34.

Abstract POSTER-THER-1418: PD-1 mediated paralysis of ovarian cancer infiltrating dendritic cells

Purpose: It is well known that the immune system impacts the clinical course of ovarian cancer suggesting that immune-based approaches may effective in treating the disease. This has led to several clinical trials of novel treatments such as antibody, vaccine, and adoptive T cell therapy. PD-1:PD-L1 axis is a major immune regulatory pathway that blunts immune effectors in the tumor microenvironment. It is well known that high surface expression of PD-1 on tumor infiltrating T cells is a sign of their exhaustion. However, the complete mechanism behind the PD-1 regulation of T cell exhaustion is yet to be explored. Recently we identified that PD-1 is also expressed on ovarian tumor-infiltrating myeloid dendritic cells (DCs) that exhibit an immunosuppressive phenotype. Our goal in this study was to understand the mechanism by which PD-1 mediates the paralysis of ovarian cancer infiltrating DCs.

Experimental procedures: PD-1+ DCs obtained from ID8 mouse model of ovarian cancer were used in this study. Data from this preclinical model was confirmed by using myeloid DCs obtained from ovarian cancer patient’s samples. Using standard flow cytometry, immunoassays (ELISA, multiplexed cytokine assay), PCR array, western blot and confocal microscopy, PD-1 mediated paralysis of ovarian cancer DCs was determined.

Results: Our data shows that blockade of surface PD-1 on ovarian cancer infiltrating DCs results in their activation by, enhancing their surface co-stimulatory molecules expression, increasing their motility, enhancing their antigen presentation capacity, and increasing their production of immunostimulatory cytokines. Also, our results suggest that PD-1 expressed on tumor DCs mediates the suppression of NFkB which occurs through SHP-2 and IKK dependent mechanisms.

Conclusion: Our study reveals that blockade of PD-1 on ovarian cancer infiltrating DCs results in the reversal of their paralysis to such an extent that it overrides their B7-H1 mediated suppression of T cells and this occurs through the reversal of PD-1 mediated tonic suppression of NFkB.

Citation Format: Lavakumar Karyampudi James Krempski, Purushottam Lamichhane, Kimberly R. Kalli, Marshall D. Behrens, Doris M. Vargas, Lynn C Hartmann, Karen E Hedin, Ellen L. Goode, Keith L. Knutson. PD-1 mediated paralysis of ovarian cancer infiltrating dendritic cells [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-THER-1418.

Tumor-infiltrating dendritic cells in cancer pathogenesis

Dendritic cells (DCs) play a pivotal role in the tumor microenvironment, which is known to affect disease progression in many human malignancies. Infiltration by mature, active DCs into the tumors confers an increase in immune activation and recruitment of disease-fighting immune effector cells and pathways. DCs are the preferential target of infiltrating T cells. However, tumor cells have means of suppressing DC function or of altering the tumor microenvironment in such a way that immune-suppressive DCs are recruited. Advances in understanding these changes have led to promising developments in cancer-therapeutic strategies targeting tumor-infiltrating DCs to subdue their immunosuppressive functions and enhance their immune-stimulatory capacity.

Plasma immune analytes in patients with epithelial ovarian cancer

OBJECTIVES

Inflammation is a common feature of epithelial ovarian cancer (EOC), and measurement of plasma markers of inflammation might identify candidate markers for use in screening or presurgical evaluation of patients with adnexal masses.

METHODS

Plasma specimens from cohorts of 100 patients with advanced EOC (AJCC Stage III and IV), 50 patients with early stage EOC (Stage I and II), and 50 patients with benign surgical conditions were assayed for concentrations of multiple cytokines, toll-like receptor agonists, and vascular growth factors via ELISA and electrochemiluminescence. Immune proteins were then analyzed for association with EOC. Differences in plasma protein levels between benign, early, and advanced EOC patient groups were assessed with and without adjustment for plasma cancer antigen 125 (CA-125) levels.

RESULTS

Out of 23 proteins tested, six-including interferon gamma (IFNγ), interleukin 6 (IL-6), IL-8, IL-10, tumor necrosis factor alpha (TNFα), and placental growth factor (PlGF)-were univariately associated with EOC (all p<0.005), and one-IL-6-was associated with early stage EOC (p<0.0001). Heat shock protein 90kDa beta member 1 (HSP90B1, gp96) was associated with EOC and early stage EOC with borderline statistical significance (p=0.039 and p=0.026, respectively). However, when adjusted for (CA-125), only HSP90B1 independently predicted EOC (p=0.008), as well as early stage EOC (p=0.014).

CONCLUSIONS

Multiple plasma cytokines, including IFNγ, IL-6, IL-8, IL-10, TNFα, PlGF, and HSP90B1 are associated with EOC. Of these, HSP90B1 is associated with EOC independent from the biomarker CA-125.

Targeted immune therapy of ovarian cancer

Clinical outcomes, such as recurrence-free survival and overall survival, in ovarian cancer are quite variable, independent of common characteristics such as stage, response to therapy, and grade. This disparity in outcomes warrants further exploration and therapeutic targeting into the interaction between the tumor and host. One compelling host characteristic that contributes both to the initiation and progression of ovarian cancer is the immune system. Hundreds of studies have confirmed a prominent role for the immune system in modifying the clinical course of the disease. Recent studies also show that anti-tumor immunity is often negated by immune regulatory cells present in the tumor microenvironment. Regulatory immune cells also directly enhance the pathogenesis through the release of various cytokines and chemokines, which together form an integrated pathological network. Thus, in the future, research into immunotherapy targeting ovarian cancer will probably become increasingly focused on combination approaches that simultaneously augment immunity while preventing local immune suppression. In this article, we summarize important immunological targets that influence ovarian cancer outcome as well as include an update on newer immunotherapeutic strategies.

Oncolytic measles virus expressing the sodium iodide symporter to treat drug-resistant ovarian cancer

Edmonston vaccine strains of measles virus (MV) have significant antitumor activity in mouse xenograft models of ovarian cancer. MV engineered to express the sodium iodide symporter gene (MV-NIS) facilitates localization of viral gene expression and offers a tool for tumor radiovirotherapy. Here, we report results from a clinical evaluation of MV-NIS in patients with taxol- and platinum-resistant ovarian cancer. MV-NIS was given intraperitoneally every 4 weeks for up to 6 cycles. Treatment was well tolerated and associated with promising median overall survival in these patients with heavily pretreated ovarian cancer; no dose-limiting toxicity was observed in 16 patients treated at high-dose levels (10(8)-10(9) TCID50), and their median overall survival of 26.5 months compared favorably with other contemporary series. MV receptor CD46 and nectin-4 expression was confirmed by immunohistochemistry in patient tumors. Sodium iodide symporter expression in patient tumors after treatment was confirmed in three patients by (123)I uptake on SPECT/CTs and was associated with long progression-free survival. Immune monitoring posttreatment showed an increase in effector T cells recognizing the tumor antigens IGFBP2 and FRα, indicating that MV-NIS treatment triggered cellular immunity against the patients' tumor and suggesting that an immune mechanism mediating the observed antitumor effect. Our findings support further clinical evaluation of MV-NIS as an effective immunovirotherapy.

Immune response profiling in early rheumatoid arthritis: discovery of a novel interaction of treatment response with viral immunity

INTRODUCTION

It remains challenging to predict the outcomes of therapy in patients with rheumatoid arthritis (RA). The objective of this study was to identify immune response signatures that correlate with clinical treatment outcomes in patients with RA.

METHODS

A cohort of 71 consecutive patients with early RA starting treatment with disease-modifying antirheumatic drugs (DMARDs) was recruited. Disease activity at baseline and after 21 to 24 weeks of follow-up was measured using the Disease Activity Score in 28 joints (DAS28). Immune response profiling was performed by analyzing multi-cytokine production from peripheral blood cells following incubation with a panel of stimuli, including a mixture of human cytomegalovirus (CMV) and Epstein-Barr virus (EBV) lysates. Profiles identified via principal components analysis (PCA) for each stimulus were then correlated with the ΔDAS28 from baseline to follow-up. A clinically meaningful improvement in the DAS28 was defined as a decrease of ≥1.2.

RESULTS

A profile of T-cell cytokines (IL-13, IL-4, IL-5, IL-2, IL-12, and IFN-γ) produced in response to CMV/EBV was found to correlate with the ΔDAS28 from baseline to follow-up. At baseline, a higher magnitude of the CMV/EBV immune response profile predicted inadequate DAS28 improvement (mean PCA-1 scores: 65.6 versus 50.2; P = 0.029). The baseline CMV/EBV response was particularly driven by IFN-γ (P = 0.039) and IL-4 (P = 0.027). Among patients who attained clinically meaningful DAS28 improvement, the CMV/EBV PCA-1 score increased from baseline to follow-up (mean +11.6, SD 25.5), whereas among patients who responded inadequately to DMARD therapy, the CMV/EBV PCA-1 score decreased (mean -12.8, SD 25.4; P = 0.002). Irrespective of the ΔDAS28, methotrexate use was associated with up-regulation of the CMV/EBV response. The CMV/EBV profile was associated with positive CMV IgG (P <0.001), but not EBV IgG (P = 0.32), suggesting this response was related to CMV exposure.

CONCLUSIONS

A profile of T-cell immunity associated with CMV exposure influences the clinical response to DMARD therapy in patients with early RA. Because CMV latency is associated with greater joint destruction, our findings suggest that changes in T-cell immunity mediated by viral persistence may affect treatment response and possibly long-term outcomes of RA.

Abstract 1873: Plasma heat shock protein 90kDa beta member 1 levels predict both early stage and advanced stage ovarian cancer independently from cancer antigen 125 in patients with an indeterminate adnexal mass

Background: Ovarian cancer (OC) is the most common cause of death among gynecologic cancers. A key reason for the high lethality of OC is that early detection of OC is uncommon, and the majority of OC patients have advanced stage disease at diagnosis. Current non-invasive tests do not adequately distinguish benign from malignant adnexal masses. Diagnostic tests that reliably distinguish early stage OC from benign conditions may lead to earlier diagnosis of OC and improved survival.

Methods: We designed a cohort study of plasma biomarkers in ovarian cancer patients. Specimens were analyzed from 100 patients with advanced OC (AJCC Stage III and IV), 50 patients with early stage OC (Stage I and II), and 50 patients with benign surgical conditions from the Mayo Ovarian SPORE Biospecimens Core. Presurgical plasma samples were assayed for multiple toll-like receptor agonists, cytokines, and vascular growth factors by ELISA and electrochemiluminescence. Biomarkers that were reliably detected in plasma were analyzed for association with OC. Differences in plasma biomarker levels between benign, early, and advanced OC patient groups were assessed using plate-adjusted logistic regression models.

Results: Out of 23 biomarkers tested, 7 were excluded due to unreliable plasma detection. Of the remaining 16 biomarkers, 6_including interferon gamma (IFNγ), interleukin 6 (IL-6), IL-8, IL-10, tumor necrosis factor alpha (TNFα), and placental growth factor (PlGF)_were univariately associated with OC (all p&lt;0.005), and one_IL-6_was associated with early stage OC (p &lt; 0.0001). Heat shock protein 90kDa beta member 1 (HSP90B1, gp96) was associated with OC and early stage OC with borderline statistical significance (p = 0.039 and p = 0.026, respectively). However, when adjusted for cancer antigen 125 (CA-125), only HSP90B1 independently predicted OC (p = 0.008), as well as early stage OC (p = 0.014).

Conclusions: The plasma cytokines IFNγ, IL-6, IL-8, IL-10, TNFα, and PlGF are associated with OC. However, after adjusting for CA-125, only HSP90B1 independently predicts OC, including early stage OC. These data warrant further investigation to determine whether measuring plasma HSP90B1 can aid in patient evaluation.

Citation Format: Matthew S. Block, Matthew J. Maurer, Krista Goergen, Kimberly R. Kalli, Courtney L. Erskine, Marshall D. Behrens, Keith L. Knutson. Plasma heat shock protein 90kDa beta member 1 levels predict both early stage and advanced stage ovarian cancer independently from cancer antigen 125 in patients with an indeterminate adnexal mass. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1873. doi:10.1158/1538-7445.AM2014-1873

Association studies of Fcγ receptor polymorphisms with outcome in HER2+ breast cancer patients treated with trastuzumab in NCCTG (Alliance) Trial N9831

Patients with HER2+ breast cancer treated with trastuzumab and chemotherapy have superior survival compared with patients treated with chemotherapy alone. Polymorphisms within FCGR2A and FCGR3A are associated with binding affinity of natural killer cells to the IgG1 portion of trastuzumab, and a polymorphism in FCGR2B (I232T) is associated with impaired regulatory activity. The association of these polymorphisms with clinical response among trastuzumab-treated patients is equivocal, with both positive and negative associations. We performed genotyping analysis on the FCGR3A V158F, FCGR2A R131H, and FCGR2B I232T polymorphisms in 1,325 patients from the N9831 clinical trial. Patients in arm A (N = 419) received chemotherapy only. Patients in arms B (N = 469) and C (N = 437) were treated with chemotherapy and trastuzumab (sequentially in arm B and concurrently in arm C). Using log-rank test and Cox proportional hazard models, we compared disease-free survival (DFS) among genotypic groups within pooled arms B/C. We found no differences in DFS between trastuzumab-treated patients who had the FCGR3A 158 V/V and/or FCGR2A 131 H/H high-affinity genotypes and patients without those genotypes. Furthermore, there was no significant interaction between FCGR3A and FCGR2A and treatment. However, there was a difference in DFS for FCGR2B I232T, with I/I patients deriving benefit from trastuzumab (P < 0.001), compared with the T carriers who did not (P = 0.81). The interaction between FCGR2B genotype and treatment was statistically significant (P = 0.03). Our analysis did not reveal an association between FcγR high-affinity genotypes and outcomes. However, it seems that the FCGR2B inhibitory gene may be predictive of adjuvant trastuzumab benefit.

Variation in NF-κB signaling pathways and survival in invasive epithelial ovarian cancer

Survival in epithelial ovarian cancer (EOC) is influenced by the host immune response, yet the key genetic determinants of inflammation and immunity that affect prognosis are not known. The nuclear factor-κB (NF-κB) transcription factor family plays an important role in many immune and inflammatory responses, including the response to cancer. We studied common inherited variation in 210 genes in the NF-κB family in 10,084 patients with invasive EOC (5,248 high-grade serous, 1,452 endometrioid, 795 clear cell, and 661 mucinous) from the Ovarian Cancer Association Consortium. Associations between genotype and overall survival were assessed using Cox regression for all patients and by major histology, adjusting for known prognostic factors and correcting for multiple testing (threshold for statistical significance, P < 2.5 × 10(-5)). Results were statistically significant when assessed for patients of a single histology. Key associations were with caspase recruitment domain family, member 11 (CARD11) rs41324349 in patients with mucinous EOC [HR, 1.82; 95% confidence interval (CI), 1.41-2.35; P = 4.13 × 10(-6)] and tumor necrosis factor receptor superfamily, member 13B (TNFRSF13B) rs7501462 in patients with endometrioid EOC (HR, 0.68; 95% CI, 0.56-0.82; P = 2.33 × 10(-5)). Other associations of note included TNF receptor-associated factor 2 (TRAF2) rs17250239 in patients with high-grade serous EOC (HR, 0.84; 95% CI, 0.77-0.92; P = 6.49 × 10(-5)) and phospholipase C, gamma 1 (PLCG1) rs11696662 in patients with clear cell EOC (HR, 0.43; 95% CI, 0.26-0.73; P = 4.56 × 10(-4)). These associations highlight the potential importance of genes associated with host inflammation and immunity in modulating clinical outcomes in distinct EOC histologies.

Accumulation of memory precursor CD8 T cells in regressing tumors following combination therapy with vaccine and anti-PD-1 antibody

Immunosuppression in the tumor microenvironment blunts vaccine-induced immune effectors. PD-1/B7-H1 is an important inhibitory axis in the tumor microenvironment. Our goal in this study was to determine the effect of blocking this inhibitory axis during and following vaccination against breast cancer. We observed that using anti-PD-1 antibody and a multipeptide vaccine (consisting of immunogenic peptides derived from breast cancer antigens, neu, legumain, and β-catenin) as a combination therapy regimen for the treatment of breast cancer-bearing mice prolonged the vaccine-induced progression-free survival period. This prolonged survival was associated with increase in number of Tc1 and Tc2 CD8 T cells with memory precursor phenotype, CD27+IL-7RhiT-betlo, and decrease in number of PD-1+ dendritic cells (DC) in regressing tumors and enhanced antigen reactivity of tumor-infiltrating CD8 T cells. It was also observed that blockade of PD-1 on tumor DCs enhanced IL-7R expression on CD8 T cells. Taken together, our results suggest that PD-1 blockade enhances breast cancer vaccine efficacy by altering both CD8 T cell and DC components of the tumor microenvironment. Given the recent success of anti-PD-1 monotherapy, our results are encouraging for developing combination therapies for the treatment of patients with cancer in which anti-PD-1 monotherapy alone may be ineffective (i.e., PD-L1-negative tumors).

Tumor hypomethylation at 6p21.3 associates with longer time to recurrence of high-grade serous epithelial ovarian cancer

To reveal biologic mechanisms underlying clinical outcome of high-grade serous (HGS) epithelial ovarian carcinomas (EOC), we evaluated the association between tumor epigenetic changes and time to recurrence (TTR). We assessed methylation at approximately 450,000 genome-wide CpGs in tumors of 337 Mayo Clinic (Rochester, MN) patients. Semi-supervised clustering of discovery (n=168) and validation (n=169) sets was used to determine clinically relevant methylation classes. Clustering identified two methylation classes based on 60 informative CpGs, which differed in TTR in the validation set [R vs. L class, P=2.9×10(-3), HR=0.52; 95% confidence interval (CI), 0.34-0.80]. Follow-up analyses considered genome-wide tumor mRNA expression (n=104) and CD8 T-cell infiltration (n=89) in patient subsets. Hypomethylation of CpGs located in 6p21.3 in the R class associated with cis upregulation of genes enriched in immune response processes (TAP1, PSMB8, PSMB9, HLA-DQB1, HLA-DQB2, HLA-DMA, and HLA-DOA), increased CD8 T-cell tumor infiltration (P=7.6×10(-5)), and trans-regulation of genes in immune-related pathways (P=1.6×10(-32)). This is the most comprehensive assessment of clinical outcomes with regard to epithelial ovarian carcinoma tumor methylation to date. Collectively, these results suggest that an epigenetically mediated immune response is a predictor of recurrence and, possibly, treatment response for HGS EOC.

Large-scale evaluation of common variation in regulatory T cell-related genes and ovarian cancer outcome

The presence of regulatory T cells (Treg) in solid tumors is known to play a role in patient survival in ovarian cancer and other malignancies. We assessed inherited genetic variations via 749 tag single-nucleotide polymorphisms (SNP) in 25 Treg-associated genes (CD28, CTLA4, FOXP3, IDO1, IL10, IL10RA, IL15, 1L17RA, IL23A, IL23R, IL2RA, IL6, IL6R, IL8, LGALS1, LGALS9, MAP3K8, STAT5A, STAT5B, TGFB1, TGFB2, TGFB3, TGFBR1, TGRBR2, and TGFBR3) in relation to ovarian cancer survival. We analyzed genotype and overall survival in 10,084 women with invasive epithelial ovarian cancer, including 5,248 high-grade serous, 1,452 endometrioid, 795 clear cell, and 661 mucinous carcinoma cases of European descent across 28 studies from the Ovarian Cancer Association Consortium (OCAC). The strongest associations were found for endometrioid carcinoma and IL2RA SNPs rs11256497 [HR, 1.42; 95% confidence interval (CI), 1.22-1.64; P = 5.7 × 10(-6)], rs791587 (HR, 1.36; 95% CI, 1.17-1.57; P = 6.2 × 10(-5)), rs2476491 (HR, = 1.40; 95% CI, 1.19-1.64; P = 5.6 × 10(-5)), and rs10795763 (HR, 1.35; 95% CI, 1.17-1.57; P = 7.9 × 10(-5)), and for clear cell carcinoma and CTLA4 SNP rs231775 (HR, 0.67; 95% CI, 0.54-0.82; P = 9.3 × 10(-5)) after adjustment for age, study site, population stratification, stage, grade, and oral contraceptive use. The rs231775 allele associated with improved survival in our study also results in an amino acid change in CTLA4 and previously has been reported to be associated with autoimmune conditions. Thus, we found evidence that SNPs in genes related to Tregs seem to play a role in ovarian cancer survival, particularly in patients with clear cell and endometrioid epithelial ovarian cancer.

Risk of ovarian cancer and the NF-κB pathway: genetic association with IL1A and TNFSF10

A missense single-nucleotide polymorphism (SNP) in the immune modulatory gene IL1A has been associated with ovarian cancer risk (rs17561). Although the exact mechanism through which this SNP alters risk of ovarian cancer is not clearly understood, rs17561 has also been associated with risk of endometriosis, an epidemiologic risk factor for ovarian cancer. Interleukin-1α (IL1A) is both regulated by and able to activate NF-κB, a transcription factor family that induces transcription of many proinflammatory genes and may be an important mediator in carcinogenesis. We therefore tagged SNPs in more than 200 genes in the NF-κB pathway for a total of 2,282 SNPs (including rs17561) for genotype analysis of 15,604 cases of ovarian cancer in patients of European descent, including 6,179 of high-grade serous (HGS), 2,100 endometrioid, 1,591 mucinous, 1,034 clear cell, and 1,016 low-grade serous, including 23,235 control cases spanning 40 studies in the Ovarian Cancer Association Consortium. In this large population, we confirmed the association between rs17561 and clear cell ovarian cancer [OR, 0.84; 95% confidence interval (CI), 0.76-0.93; P = 0.00075], which remained intact even after excluding participants in the prior study (OR, 0.85; 95% CI, 0.75-0.95; P = 0.006). Considering a multiple-testing-corrected significance threshold of P < 2.5 × 10(-5), only one other variant, the TNFSF10 SNP rs6785617, was associated significantly with a risk of ovarian cancer (low malignant potential tumors OR, 0.85; 95% CI, 0.79-0.91; P = 0.00002). Our results extend the evidence that borderline tumors may have a distinct genetic etiology. Further investigation of how these SNPs might modify ovarian cancer associations with other inflammation-related risk factors is warranted.

The ratios of CD8+ T cells to CD4+CD25+ FOXP3+ and FOXP3- T cells correlate with poor clinical outcome in human serous ovarian cancer

Ovarian cancer is an immune reactive malignancy with a complex immune suppressive network that blunts successful immune eradication. This suppressive microenvironment may be mediated by recruitment or induction of CD4⁺ regulatory T cells (Tregs). Our study sought to investigate the association of tumor-infiltrating CD4⁺CD25⁺FOXP3⁺ Tregs, and other immune factors, with clinical outcome in serous ovarian cancer patients. We performed immunofluorescence and quantification of intraepithelial tumor-infiltrating triple positive Tregs (CD4⁺CD25⁺FOXP3⁺), as well as CD4⁺CD25⁺FOXP3^-, CD3⁺ and CD8⁺ T cells in tumor specimens from 52 patients with high stage serous ovarian carcinoma. Thirty-one of the patients had good survival (i.e. > 60 months) and 21 had poor survival of < 18 months. Total cell counts as well as cell ratios were compared among these two outcome groups. The total numbers of CD4⁺CD25⁺FOXP3⁺ Tregs, CD4⁺CD25⁺FOXP3^-, CD3⁺ and CD8⁺ cells were not significantly different between the groups. However, higher ratios of CD8⁺/CD4⁺CD25⁺FOXP3⁺ Treg, CD8⁺/CD4⁺ and CD8/CD4⁺CD25⁺FOXP3^- cells were seen in the good outcome group when compared to the patients with poor outcome. These data show for the first time that the ratios of CD8⁺ to both CD4⁺CD25⁺FOXP3⁺ Tregs and CD4⁺CD25⁺FOXP3^- T cells are associated with disease outcome in ovarian cancer. The association being apparent in ratios rather than absolute count of T cells suggests that the effector/suppressor ratio may be a more important indicator of outcome than individual cell count. Thus, immunotherapy strategies that modify the ratio of CD4⁺CD25⁺FOXP3⁺ Tregs or CD4⁺CD25⁺FOXP3^- T cells to CD8⁺ effector cells may be useful in improving outcomes in ovarian cancer.

The immune system in the pathogenesis of ovarian cancer

Clinical outcomes in ovarian cancer are heterogeneous even when considering common features such as stage, response to therapy, and grade. This disparity in outcomes warrants further exploration into tumor and host characteristics. One compelling host characteristic is the immune response to ovarian cancer. While several studies have confirmed a prominent role for the immune system in modifying the clinical course of the disease, recent genetic and protein analyses also suggest a role in disease incidence. Recent studies also show that anti-tumor immunity is often negated by immune suppressive cells present in the tumor microenvironment. These suppressive immune cells also directly enhance the pathogenesis through the release of various cytokines and chemokines, which together form an integrated pathologic network. Thus, future research into immunotherapy targeting ovarian cancer will likely become increasingly focused on combination approaches that simultaneously augment immunity while preventing local immune suppression or by disrupting critical cytokine networks.

Abstract B123: Analysis of the associations of FC gamma receptor polymorphisms (FCGR3A, FCGR2A, and FCGR2B) with outcome in HER2+ breast cancer patients treated with trastuzumab in NCCTG (Alliance) trial N9831

Background: In the adjuvant setting, HER2 breast cancer patients treated with trastuzumab along with chemotherapy have superior survival compared to patients treated with chemotherapy alone (Perez EA, et al. J Clin Oncol. 2013 31:2115-22). Functional evidence suggests a role for the FC gamma receptor genes in antibody response. Mice deficient in the FC gamma receptor genes show significantly reduced antitumor effect. Polymorphisms within FCGR2A and FCGR3A are associated with binding affinity of natural killer cells to the IgG1 portion of trastuzumab and a polymorphism in FCGR2B (I232T, T allele) is associated with impaired negative regulatory activity. Association of FC gamma receptor polymorphisms with clinical response among trastuzumab-treated patients is equivocal with both positive (Musolino A, et al. J Clin Oncol. 2008 26:1789-96) and negative associations (Hurvitz SA, et al. Clin Cancer Res. 2012 18:3478-86), a lack of sufficiently powered clinical samples and a lack of cohorts with clearly demonstrated survival benefit to trastuzumab containing regimens.

Methods: Genomic DNA was analyzed for FcyRIIIa, FcyRIIa, and FcyRIIb polymorphisms (FCGR3A V158F, FCGR2A H131R and FCGR2B I232T) using Taqman SNP real-time PCR assays (Applied Biosystems) in 1,336 patients from the N9831 clinical trial of adjuvant trastuzumab in HER2+ breast cancer. 1325 patients were evaluable. Patients in Arm A (N=419) received chemotherapy only. Patients in Arms B (N=469) and C (N= 437) were treated with chemotherapy and trastuzumab (sequentially in Arm B and concurrently in Arm C). We performed Kaplan-Meier analyses of disease free survival (DFS) by arm and genotype for each polymorphism.

Results: There were only minor differences in demographics and tumor features when comparing the subset with DNA to other N9831 participants who did not provide DNA. Patients who provided DNA in Arms B and C demonstrated superior DFS relative to patients in Arm A who provided DNA (p&lt;0.001). Genotype distributions in the N9831 population for FCGR2A and FCGR3A polymorphisms were in Hardy-Weinberg equilibrium, p&gt;0.05 and FCGR2B, p&gt;0.01. In contrast to previous reports in the metastatic setting, we did not find that trastuzumab-treated patients who had the FCGR3A 158 V and/or FCGR2A 131 H genotypes demonstrated superior DFS to those without those genotypes. Similarly, we did not see an effect of FCGR2B I232T with the exception that I/I patients (p&lt;0.001) apparently derived more benefit, in terms of DFS, from trastuzumab than did T carriers (p=0.81). However, 5-year DFS was not different between these two groups, I/I and T carriers within Arms B/C.

Conclusions: Our analysis failed to reveal strong associations between FCGR genotypes and outcome in patients with HER2+ breast cancer treated with trastuzumab. While the present data do not preclude a functional role for FC gamma receptors in the clinical activity of trastuzumab, the results suggest that these naturally occurring polymorphisms may have minor (if any) impact in the adjuvant setting, which is consistent with previous findings by Hurvitz and colleagues.

Citation Format: Mark Pegram, Rebecca M. Olson, Nadine Norton, Kathleen Tenner, Karla L. Ballman, Raphael Clynes, Keith L. Knutson, Edith A. Perez. Analysis of the associations of FC gamma receptor polymorphisms (FCGR3A, FCGR2A, and FCGR2B) with outcome in HER2+ breast cancer patients treated with trastuzumab in NCCTG (Alliance) trial N9831. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B123.

Abstract A82: Metronomic cyclophosphamide followed by a multi-peptide folate receptor vaccine for ovarian and breast cancer immunotherapy in the setting of minimal residual disease - a feasibility study

Background: Current options to prevent ovarian and breast cancer recurrence are limited. However, signs of anti-tumor immunity are associated with improved survival in patients who have experienced a number of different malignancies. After identifying folate receptor alpha (FR)-derived class II-binding peptides recognized by lymphocytes from patients who previously had breast or ovarian cancer, we developed a multi-peptide vaccine with five peptides, each of which was recognized by more than 25% of the patients. We combined this vaccine with metronomic cyclophosphamide in an attempt to selectively reduce T regulatory cells in the periphery and the tumor microenvironment.

Methods: We obtained an Investigational New Drug approval from the Food and Drug Administration to perform a phase I study in 22 patients who were currently in remission from their breast or ovarian cancer. Participants were required to be at least 90 days past any treatment for their disease (other than hormonal treatment, if applicable) and show no current evidence of disease. After 28 days of metronomic cyclophosphamide, six monthly intradermal injections of the vaccine were given. The primary endpoints of the trial are safety and immunogenicity.

Results: To date, 15 of 22 patients have enrolled (7 breast and 8 ovarian cancer patients). 4 breast and 2 ovarian cancer patients are available for toxicity evaluation. No serious major adverse events have been observed, with the expected injection site reactions being the primary toxicity experienced by most participants; grade 2 decreased white blood cell counts were observed in 3 patients at completion of cyclophosphamide. Two patients went off study prior to completing all six vaccinations, one for vision changes, and one for disease progression. Immune monitoring is underway, with major assays being ELISAs for high-affinity IgG targeting the FR and FR-peptide specific ELIspots. These data will be presented at the meeting.

Conclusions: Metronomic cyclophosphamide followed by intradermal vaccinations with a multi-peptide vaccine targeting the tumor antigen FR appears to be a tolerable regimen at this preliminary point of the study. With the exception of vision changes in one patient, no serious safety concerns have arisen. Pursuit of this strategy in further clinical study will require demonstration of FR-specific immune responses, an acceptable toxicity profile, and demonstration that T regulatory cells are altered in the periphery.

Citation Format: Kimberly R. Kalli, Courtney L. Erskine, James W. Krempski, Linda M. Benson, Vera J. Suman, Douglas J. Padley, Allan B. Dietz, Timothy J. Hobday, Amy C. Degnim, Lynn C. Hartmann, Matthew S. Block, Keith L. Knutson. Metronomic cyclophosphamide followed by a multi-peptide folate receptor vaccine for ovarian and breast cancer immunotherapy in the setting of minimal residual disease - a feasibility study. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A82.

Utility of progranulin and serum leukocyte protease inhibitor as diagnostic and prognostic biomarkers in ovarian cancer

BACKGROUND

Epithelial ovarian cancer (EOC) is the fifth leading cause of cancer-related death in females and leading gynecologic cause of cancer-related death. Despite the identification of a number of serum biomarkers, methods to identify early-stage disease and predict prognosis remain scarce. We have evaluated two biologically connected serum biomarkers, serum leukocyte protease inhibitor (SLPI) and progranulin (PGRN).

METHODS

Two-hundred frozen plasma samples were acquired from the Mayo Clinic Biospecimen Repository for Ovarian Cancer Research. Samples were obtained from 50 patients with benign conditions, 50 with American Joint Committee on Cancer (AJCC) stage I and II EOC, and 100 with AJCC stage III and IV EOC. Samples were obtained before surgical resection of a mass and were analyzed for absolute levels of SLPI and PGRN using ELISA assays. Receiver-operator characteristic curves were generated for SLPI and PGRN. Median follow-up was 48 months.

RESULTS

Absolute levels of SLPI were significantly elevated in patients with EOC compared with benign disease and predicted the presence of EOC (AUC of 0.812; P = 0.04); SLPI remained elevated in the subset of patients with normal CA-125. PGRN levels were not significantly increased in patients with early-stage or late-stage EOC as a whole, but an increase in PGRN levels was associated with decreased overall survival in advanced EOC.

CONCLUSIONS

SLPI levels are elevated in EOC, and SLPI shows promise as a diagnostic biomarker for patients with both elevated and normal CA-125 levels. An increase in PGRN is associated with decreased overall survival.

IMPACT

SLPI is elevated in EOC and warrants investigation in a screening study in women at risk for EOC.

Generation of adaptive HER2-specific immunity in HER2 breast cancer patients by addition of trastuzumab to chemotherapy in the adjuvant setting: NCCTG (Alliance) study N9831

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Background: In the adjuvant setting, patients with HER2 breast cancer treated with trastuzumab and chemotherapy have superior survival compared to patients treated with chemotherapy alone. We previously showed that trastuzumab and chemotherapy induces HER2-specific antibodies which correlate with response to therapy in patients with HER2+ metastatic breast cancer. It remained unclear from those studies, however, whether the HER2-specific immunity played a role and if antibody immunity was associated with improved disease free survival in the adjuvant setting. In the present study, we addressed these questions by analyzing sera samples from a subset of patients enrolled in the NCCTG adjuvant trial, N9831, which includes an arm (Arm A) in which trastuzumab was not used. Arms B and C received trastuzumab sequentially or concurrently to chemotherapy, respectively. Methods: Pre-and post-treatment initiation sera were obtained from 50 women enrolled in N9831 (22 Arm A; 14 Arm B, and 14 Arm C). Lambda IgG antibodies (to avoid detection of trastuzumab) to HER2 were measured and presented as an index (>0.2 was considered a positive response). Results: Prior to therapy, across all three arms, N9831 patients had similar mean HER2 IgG levels (0.19 units in Arm A, 0.14 in Arm B, and 0.23 in Arm C, P=0.85). Following treatment, the mean levels of antibodies increased in Arm B to 0.35 units and in Arm C to 0.56 units and were higher (p<0.001) than in Arm A where levels did not increase. The proportion of patients who demonstrated antibody immunity increased by 9% in Arm A, 50% in Arm B and 28% in Arm C (P=0.026). Although the event rate was low in this cohort, Cox modeling suggested that larger increases in antibodies were associated with improved disease free survival (HR=0.23; p=0.04). Conclusions: These results show that the increased antibody immunity observed in adjuvant patients treated with combination trastuzumab and chemotherapy is clinically significant and results from the inclusion of trastuzumab. The findings may have important implications for improving treatment outcomes in patients treated with trastuzumab.

Combination trastuzumab and chemotherapy to induce immunity to multiple tumor antigens in patients with HER2-positive metastatic breast cancer: NCCTG (Alliance) studies N0337 and N98-32-52

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Background: The addition of trastuzumab to chemotherapy improves responses to therapy and extends survival among patients with metastatic HER2 breast cancer. Several mechanisms have been proposed for the activity of this combination therapy. Trastuzumab, specifically, is thought to activate NK cells and blunt HER2 signaling. Prior work from us has shown that combination trastuzumab and chemotherapy induces HER2-specific antibodies which correlate with response to therapy. Despite that, it remains unclear whether the immunity that was induced was due to complexing of non-tumor derived HER2 or antigen derived from the tumor site. In the present work, we addressed this question by assessing if combination therapy induced epitope spreading to tumor antigens other than HER2. Methods: Pre-and post-treatment sera were obtained from 56 women enrolled in 2 NCCTG clinical trials, N0337 and 98-32-52. IgG antibodies to HER2 intracellular domain (HER2), p53, IGFBP2, CEA and tetanus toxoid (TT) were examined using ELISAs. Sera from an age-matched group (N=56) of controls and 12 patients treated in the adjuvant setting were also examined. Results: Prior to therapy, metastatic patients had higher IgG levels (≥ 2-fold) to p53 and HER2 but not CEA, IGFBP2 and TT, relative to the controls. Similarly, adjuvant patients had elevated IgGs to multiple tumor antigens prior to therapy, relative to controls. Following therapy, levels of IgG to IGFBP2, HER2, and p53 increased in 81% of metastatic patients, with mean increases of 3.2 (±0.6 sem), 6.2 (±2.7) and 2.7 (±0.7) fold, respectively (p<0.05). Levels of antibodies to TT and CEA were not elevated by treatment. In contrast, IgGs were not increased in adjuvant patients; consistent with the idea that immunity depends on the presence of threshold levels of antigens. Conclusions: These results show that combination treatment induces adaptive immunity to antigens released by tumor and that metastatic patients remain capable of responding immunologically to their cancer. Thus, in metastatic breast cancer patients, combination trastuzumab and chemotherapy may behave as a vaccine.

Toward understanding the genetics of regulatory T cells in ovarian cancer

Tumor-infiltrating regulatory T cells (Tregs) promote immune evasion and are associated with poor disease outcome in patients affected by various malignancies. We have recently demonstrated that several, inherited single nucleotide polymorphisms affecting Treg-related genes influence the survival of ovarian cancer patients, providing novel insights into possible mechanisms of immune escape.

Abstract 3476: Higher plasma levels of heparan sulfate are associated with improved survival of patients with advanced ovarian cancer

Background: Ovarian cancer (OC) is the leading cause of gynecologic cancer death in the United States. Survival in advanced OC is highly variable and is impacted by the endogenous anti-tumor immune response. Toll-like receptors (TLR) on tumor-infiltrating leukocytes can modulate anti-OC immunity. Heparan sulfate (HS) is an oligosaccharide component of the extracellular matrix that, when released, binds and triggers TLR-4 to induce production of multiple cytokines; HS is liberated from the extracellular matrix by heparanase, which is overexpressed by many ovarian cancers. We therefore explored the association between plasma levels of HS, heparanase, proinflammatory and immunosuppressive cytokines, and survival in patients with advanced OC.

Methods: We designed a two stage cohort study of plasma biomarkers in ovarian cancer patients. For the pilot stage, we enrolled 100 patients with advanced OC (AJCC Stage III and IV), 50 patients with early stage OC (Stage I and II), and 50 patients with benign surgical conditions from the Mayo Ovarian SPORE Biospecimens Core. For the expansion stage, 257 patients with advanced OC were enrolled. Presurgical plasma samples were assayed for HS, heparanase, and multiple cytokines by ELISA and electrochemiluminescence. Differences in plasma levels between benign, early, and advanced OC patient groups were assessed using plate-adjusted linear models. Associations between plasma levels of HS and heparanase with overall survival in advanced OC patients were assessed by Cox proportional hazards models using a log2 transformation; total effects across stages were estimated using a meta-analysis approach.

Results: In the pilot cohort, soluble HS levels were similar in control (mean +/ STD: 88.26 +/- 32.23), early stage (93.91 +/- 37.77), and advanced OC (93.55 +/- 40.44), with similar values observed in the expansion cohort (129.29 +/- 95.64). There was no correlation between heparanase and HS levels. Higher levels of HS were associated with improved overall survival (log2 HR = 0.62, p = 0.042; HR = 0.84, p = 0.014; HR = 0.82, 95% CI: 0.71-0.93, p = 0.003 for the pilot, expansion, and combined sets, respectively). There was no association between heparanase levels and overall survival (all p &gt; 0.45).

Conclusions: Neither soluble HS nor heparanase were elevated in presurgical OC patients relative to controls; however, higher levels of HS were associated with improved survival in patients with advanced OC. These results suggest that HS may play a key role in modulating the innate immune response to OC.

Citation Format: Matthew S. Block, Matthew J. Maurer, Krista M. Goergen, Courtney L. Erskine, Marshall D. Behrens, Kimberly R. Kalli, Keith L. Knutson. Higher plasma levels of heparan sulfate are associated with improved survival of patients with advanced ovarian cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3476. doi:10.1158/1538-7445.AM2013-3476

Inherited variants in regulatory T cell genes and outcome of ovarian cancer

Although ovarian cancer is the most lethal of gynecologic malignancies, wide variation in outcome following conventional therapy continues to exist. The presence of tumor-infiltrating regulatory T cells (Tregs) has a role in outcome of this disease, and a growing body of data supports the existence of inherited prognostic factors. However, the role of inherited variants in genes encoding Treg-related immune molecules has not been fully explored. We analyzed expression quantitative trait loci (eQTL) and sequence-based tagging single nucleotide polymorphisms (tagSNPs) for 54 genes associated with Tregs in 3,662 invasive ovarian cancer cases. With adjustment for known prognostic factors, suggestive results were observed among rarer histological subtypes; poorer survival was associated with minor alleles at SNPs in RGS1 (clear cell, rs10921202, p=2.7×10(-5)), LRRC32 and TNFRSF18/TNFRSF4 (mucinous, rs3781699, p=4.5×10(-4), and rs3753348, p=9.0×10(-4), respectively), and CD80 (endometrioid, rs13071247, p=8.0×10(-4)). Fo0r the latter, correlative data support a CD80 rs13071247 genotype association with CD80 tumor RNA expression (p=0.006). An additional eQTL SNP in CD80 was associated with shorter survival (rs7804190, p=8.1×10(-4)) among all cases combined. As the products of these genes are known to affect induction, trafficking, or immunosuppressive function of Tregs, these results suggest the need for follow-up phenotypic studies.

Optimizing patient derived mesenchymal stem cells as virus carriers for a phase I clinical trial in ovarian cancer

Background

Mesenchymal stem cells (MSC) can serve as carriers to deliver oncolytic measles virus (MV) to ovarian tumors. In preparation for a clinical trial to use MSC as MV carriers, we obtained cells from ovarian cancer patients and evaluated feasibility and safety of this approach.

Methods

MSC from adipose tissues of healthy donors (hMSC) and nine ovarian cancer patients (ovMSC) were characterized for susceptibility to virus infection and tumor homing abilities.

Results

Adipose tissue (range 0.16-3.96 grams) from newly diagnosed and recurrent ovarian cancer patients yielded about 7.41×10⁶ cells at passage 1 (range 4–9 days). Phenotype and doubling times of MSC were similar between ovarian patients and healthy controls. The time to harvest of 3.0×10⁸ cells (clinical dose) could be achieved by day 14 (range, 9–17 days). Two of nine samples tested had an abnormal karyotype represented by trisomy 20. Despite receiving up to 1.6×10⁹ MSC/kg, no tumors were seen in SCID beige mice and MSC did not promote the growth of SKOV3 human ovarian cancer cells in mice. The ovMSC migrated towards primary ovarian cancer samples in chemotaxis assays and to ovarian tumors in athymic mice. Using non-invasive SPECT-CT imaging, we saw rapid co-localization, within 5–8 minutes of intraperitoneal administration of MV infected MSC to the ovarian tumors. Importantly, MSC can be pre-infected with MV, stored in liquid nitrogen and thawed on the day of infusion into mice without loss of activity. MV infected MSC, but not virus alone, significantly prolonged the survival of measles immune ovarian cancer bearing animals.

Conclusions

These studies confirmed the feasibility of using patient derived MSC as carriers for oncolytic MV therapy. We propose an approach where MSC from ovarian cancer patients will be expanded, frozen and validated to ensure compliance with the release criteria. On the treatment day, the cells will be thawed, washed, mixed with virus, briefly centrifuged and incubated for 2 hours with virus prior to infusion of the virus/MSC cocktail into patients.