Low Number Of Tumor-infiltrating Lymphocytes Research Articles

CTIM-33. EFFICACY AND SAFETY STUDY OF NEOADJUVANT EFINEPTAKIN ALFA (NT-I7) AND PEMBROLIZUMAB IN RECURRENT GLIOBLASTOMA

Abstract Glioblastoma (GBM) is the most common and aggressive form of brain tumor in adults. Despite maximal surgical resection, irradiation, and chemotherapy, median overall survival (OS) for recurrent GBM (rGBM) remains at only 30 weeks. GBM tumors have an immune-suppressive microenvironment with low numbers of tumor-infiltrating lymphocytes (TILs). Interleukin 7 (IL-7) plays a key role in T cell homeostasis and survival, with IL-7 inducing T cell expansion in lymphopenic conditions. Efineptakin alfa (NT-I7), a long-acting IL-7, has been shown to increase effector CD8 T cells and reduce suppressor T-regulatory cells in murine GBM models, with subsequently improved OS. We recently completed a Phase I study in newly diagnosed GBM patients which showed that NT-I7 is safe, well-tolerated, and increased absolute lymphocyte counts (ALCs), and determined maximum tolerated dose for Phase II. We hypothesized that NT-I7 may not only mitigate GBM treatment-associated immune suppression, but also potentiate the effect of immune checkpoint blockade, leading to an increase in TILs and improved survival. The purpose of this study is to evaluate the safety and efficacy of combining NT-I7 and pembrolizumab in rGBM patients. This is an open-label, single arm one-stage Phase II study of NT-I7 and pembrolizumab as neoadjuvant and adjuvant therapy with surgery for adult patients with rGBM. We plan to enroll 30 evaluable patients, including a 6-patient safety run-in. The primary endpoint is the 9-month OS rate. Secondary endpoints include progression-free survival, objective response rate, changes in ALC, and adverse events profile. The correlative endpoints include studies to assess the anti-glioma immune response, changes in T cell subsets and functionality, peripheral cytokine quantification, and immunohistochemical analysis of GBM tissue. Longitudinal cerebrospinal fluid proteomics is optional. This study opened in Jan 2023. Six (6) of the planned thirty (30) patients had been enrolled by time of submission.

Efficacy and safety study of neoadjuvant efineptakin alfa (NT-I7) and pembrolizumab in recurrent glioblastoma.

TPS2085 Background: Glioblastoma (GBM) is the most common and aggressive form of brain tumor in adults. Despite maximal surgical resection, irradiation, and chemotherapy, median overall survival (OS) remains at only 30 weeks for recurrent GBM (rGBM) patients, emphasizing the need for novel treatments. GBM tumors are immunologically ‘cold,’ in that they have an immune-suppressive microenvironment with a low number of tumor-infiltrating lymphocytes (TIL). Interleukin 7 (IL-7) plays a key role in T cell development and survival. The physiological level of IL-7 increases to stimulate T cell expansion in lymphopenic condition. Previous studies have shown that lymphopenic GBM patients have shorter survival. However, their IL-7 levels are unexpectedly low. Efineptakin alfa (NT-I7), a long-acting IL-7, has been shown to increase effector CD8 T cells and reduce suppressor T-regulatory cells in murine GBM models, with subsequently improved OS. Further, we recently completed a Phase I study which showed that NT-I7 is safe, well- tolerated, and increased absolute lymphocyte counts (ALC) in newly diagnosed GBM patients. Phase II dosing was determined through this Phase I study reaching maximum tolerated dose. Thus, we hypothesized that NT-I7 may reverse GBM-associated immune suppression and potentiate the effect of an immune checkpoint inhibitor, leading to an increase in TILs and improved survival. Our preliminary data suggests that combining NT-I7 with pembrolizumab, an anti-PD-1 antibody, improves survival in murine glioma models. The purpose of this study is to evaluate the safety and efficacy of combining NT-I7 and pembrolizumab in rGBM patients. Methods: This is an open-label single arm one-stage Phase II study of NT-I7 and pembrolizumab as neoadjuvant and adjuvant therapy with surgery for adult patients with rGBM. We plan to enroll 30 evaluable patients, including a 6-patient safety run-in. Key eligibility criteria include candidates willing to undergo clinically indicated resection or biopsy, age ≥ 18 years, Karnofsky performance status ≥ 70, and dexamethasone dose > 2 mg/day ≤ 2 days prior to registration. The primary endpoint is a 9-month OS rate. Secondary endpoints include progression-free survival, objective response rate, changes in ALC, and adverse events profile. The correlative endpoints include studies to assess the anti-glioma immune response, changes in T cell subsets, T cell effector function, cytokine analysis, and immunohistochemical analysis of GBM tissue. Longitudinal cerebrospinal fluid proteomics is optional. This study opened on 1/20/2023. Two of the planned 30 patients had been enrolled by submission on 2/14/2023. Clinical trial information: NCT05465954 .

Abstract 700: Induction of cancer-specific T-cell responses in patients immunized with P10s-PADRE vaccine

Abstract Introduction: HR+/HER2− breast cancer is the most common form of breast cancer in the United States. HR+/HER2− tumors are known for a low number of tumor-infiltrating lymphocytes (TILs) and considered less immunogenic than other breast cancer subtypes. We have demonstrated that vaccination with P10s-PADRE, a carbohydrate-mimetic-based peptide, cancer vaccine in combination with standard-of-care chemotherapy in HR+/HER2− breast cancer patients led to an increase in TILs and stromal CD3+ T cells. The current study was performed to determine the vaccine specificity and anti-tumor functionality of T cells in treated patients. Methods: Peripheral blood mononuclear cells (PBMCs) collected at the baseline and after vaccination were used in T-cell assays by multi-color ELISpot, examining Th1, Th2, and cytotoxic responses. PBMCs were also interrogated for the vaccine-induced changes in immune gene expression by next-generation RNA-seq analysis. Results: We observed a significant increase in IFN-g, but not in IL-5 or IL-10, responses in post-immune PBMCs after stimulation with P10s, P10s-PADRE and polyclonal stimulation of T cells by anti-CD3/CD28 antibodies. Stimulation with cancer cell lysate resulted in a strikingly high IFN-g response in post-immune samples. Determining the trio of IFN-g, GzB, and IL-2 together with CD4/CD8 cell proliferation assays of consequent post vaccination specimens established the dynamics of effector T-cell populations. RNA-seq data clearly distinguished post-treatment samples by the increase in immune cell activation, cytokine response, and antigen presentation. Conclusions: The data indicate that immunization of HR+/HER2− breast cancer patients with P10s-PADRE in combination with chemotherapy leads to specific activation of T-cells that recognize breast cancer cells. Improving immunogenicity of such immunologically cold tumors could increase the effectiveness of standard therapeutic approaches. Citation Format: John J. Lee, Bernice C. Nounamo, Fariba Jousheghany, Issam Makhoul, Eric R. Siegel, Thomas Kieber-Emmons, Behjatolah Monzavi-Karbassi. Induction of cancer-specific T-cell responses in patients immunized with P10s-PADRE vaccine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 700.

The role of peritumoral CD8 + /TIA1 + lymphocytes in hepatocellular carcinoma aggressiveness and recurrence after surgical resection

Hepatocellular carcinoma (HCC) is characterized by a low mutation burden and a relatively low number of tumor-infiltrating lymphocytes (TILs), making still difficult to identify targets for specific therapies. The aim of this study was the identification of the prognostic role of TILs in HCC, focusing on their distribution and status of activation. We retrospectively enrolled 41 patients, undergone to liver resection for HCC. A significant increase of CD8 + intratumoral lymphocytes was observed in HCCs with prevalent solid architecture, but with a higher PD-1/TIA1 ratio, suggesting that HCCs with solid architecture have more peri-tumoral lymphocytes, but with minor functionality. At multivariate and univariate analyses, TIA1/CD8 ratio correlated with tumor recurrence, meaning that HCC with more activated TILs are characterized by a higher tumor aggressiveness. The use of a feasible and cheap immunohistochemical panel can help in post-surgical prognostic stratification, focusing not only in the raw number and density of TILs, but more on their state of activation and morphology.

Intratumoral T-cell repertoires in DNA mismatch repair-proficient and -deficient colon tumors containing high or low numbers of tumor-infiltrating lymphocytes

ABSTRACT Colon tumors with deficient DNA mismatch repair (dMMR) are generally infiltrated by T cells more densely than tumors with proficient mismatch repair (pMMR). However, high numbers of tumor-infiltrating lymphocytes (TILs) are found in select pMMR tumors, and low numbers of TILs are seen in select dMMR tumors. In this study, we compared T-cell repertoires in 20 pMMR and 27 dMMR colon tumors with high and low TIL counts. We found that T cells in dMMR tumors are more clonal and their repertoire is less rich compared with T cells in pMMR tumors. In the dMMR group, T cells in TIL-high tumors were more clonal and their repertoire was less rich compared with T cells in TIL-low tumors, but in the pMMR group, T-cell diversity in TIL-high tumors was comparable to T-cell diversity in TIL-low tumors. These findings suggest that T cells clonally expand in dMMR tumors, possibly in response to MMR deficiency-induced tumor neoantigens.

Large, Anionic Liposomes Enable Targeted Intraperitoneal Delivery of a TLR 7/8 Agonist To Repolarize Ovarian Tumors' Microenvironment.

Ovarian cancer is the most lethal gynecological malignancy in the United States. Current standard of treatment includes surgical debulking and chemotherapy, such as cisplatin and paclitaxel. However, the patients' response rate for chemotherapy in ovarian cancer is not optimal, and they often develop chemoresistance and suffer from side effects. Current clinical trials make extensive use of immune checkpoint blockade (ICB) as a novel cancer immunotherapeutic strategy against ovarian tumors. However, the response rates for ICB antibodies remain limited to 10-20% of treated ovarian cancer patients despite the success of this approach in melanoma, renal, head and neck, and nonsmall cell lung cancers. This lack of efficacy is often attributed to the "cold" immune status of ovarian tumors, as these tumors often have a low number of tumor-infiltrating lymphocytes (TILs) but a high number of suppressive immune cells, including tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), or regulatory T cells (Tregs). Repolarizing TAMs could be a promising strategy to reshape the tumor immune microenvironment and promote antitumor activity when combined with ICBs. Toll-like receptor (TLR) 7 and 8 agonists, such as imiquimod and resiquimod, are potent immunostimulatory molecules with potential to repolarize macrophages. However, these small molecules have poor pharmacokinetic profiles and can induce severe side effects when administered systemically. Previously, our group demonstrated that various large, anionic nanomaterials (silica, PLGA, and polystyrene) specifically target TAMs when administered intraperitoneally (IP) to ovarian tumor-bearing mice. In the present study, we demonstrate that large, anionic liposomes administered IP also efficiently localize to TAMs and can be used to target the delivery of resiquimod. Resiquimod delivered in this targeted fashion promoted activation of M1 macrophages and T cell infiltration, while reducing the percentage of Tregs in the tumor microenvironment. Finally, liposome-formulated resiquimod significantly enhanced the efficacy of PD1 blockade against syngeneic ovarian tumors. We anticipate that further optimization of our liposomal delivery strategy can generate a clinically relevant strategy for more effective and safer immunotherapy for ovarian cancer patients.

Tumor-infiltrating lymphocytes in triple negative breast cancer

The aim of this retrospective study is to assess the prognostic value of tumor-infiltrating lymphocytes in triple negative breast carcinomas that lack both estrogen, progesterone receptors and Her2 amplification.The group of triple negative carcinomas has worse survival rates than other molecular subgroups of breast cancer, but at the same time it is very heterogeneous, and therefore requires the search for additional prognostic factors to improve the prognosis of patients.Materials and methods. The study included 350 samples of biopsies and surgical material from patients with stage I–III triple negative breast cancer who had not previously received chemotherapy. The median follow-up was 3.8 years for overall survival and 3.2 years for relapse-free survival. The prognostic value of tumor-infiltrating lymphocytes was evaluated by Kaplan–Meyer survival curves with a log-rank test, and one- and multifactor regression analysis according to the proportional risks Cox model.Results. Kaplan–Meier survival curves showed statistically significant relationships between tumor-infiltrating lymphocytes and overall and recurrence-free survival with a general trend to improve data for tumors with high lymphocyte volume. Proportional risks Cox model showed that tumors with a high number of tumor-infiltrating lymphocytes have statistically significantly better overall and recurrence-free survival rates (compared with tumors with a low number of tumor-infiltrating lymphocytes). The Kappa coefficient for interobserver variability was 0.79. It indicates a high level of agreement between pathologists in the evaluation of histological material.Conclusions. The high number of tumor-infiltrating lymphocytes in triple negative breast cancers is statistically significantly associated with better overall and recurrence-free survival rates. Assessment of tumor-infiltrating lymphocytes is rapid and does not require additional training, which makes this prognostic marker convenient to use.

The Molecular and Microenvironmental Landscape of Glioblastomas: Implications for the Novel Treatment Choices.

Glioblastoma (GBM) is the most frequent and aggressive primary central nervous system tumor. Surgery followed by radiotherapy and chemotherapy with alkylating agents constitutes standard first-line treatment of GBM. Complete resection of the GBM tumors is generally not possible given its high invasive features. Although this combination therapy can prolong survival, the prognosis is still poor due to several factors including chemoresistance. In recent years, a comprehensive characterization of the GBM-associated molecular signature has been performed. This has allowed the possibility to introduce a more personalized therapeutic approach for GBM, in which novel targeted therapies, including those employing tyrosine kinase inhibitors (TKIs), could be employed. The GBM tumor microenvironment (TME) exerts a key role in GBM tumor progression, in particular by providing an immunosuppressive state with low numbers of tumor-infiltrating lymphocytes (TILs) and other immune effector cell types that contributes to tumor proliferation and growth. The use of immune checkpoint inhibitors (ICIs) has been successfully introduced in numerous advanced cancers as well as promising results have been shown for the use of these antibodies in untreated brain metastases from melanoma and from non-small cell lung carcinoma (NSCLC). Consequently, the use of PD-1/PD-L1 inhibitors has also been proposed in several clinical trials for the treatment of GBM. In the present review, we will outline the main GBM molecular and TME aspects providing also the grounds for novel targeted therapies and immunotherapies using ICIs for GBM.

Predictive value of tumor-infiltrating lymphocytes for pathological response to neoadjuvant chemotherapy in breast cancer patients with axillary lymph node metastasis

We investigated the role of tumor-infiltrating lymphocytes (TILs) in pretreatment primary breast cancer to predict pathological response to neoadjuvant chemotherapy (NAC) in patients with clinical node-positive disease (cN +). The subjects of this study were 60 patients with cN + , who received NAC followed by breast surgery with axillary lymph node dissection (ALND). We conducted a semi-quantitative assessment of TILs in pretreatment primary tumors and their association with clinicopathological factors and axillary lymph node metastasis. We observed a higher number of TILs in tumors with negative hormone receptors, positive human epidermal growth factor receptor 2, or high Ki67. TILs were associated with a favorable response to NAC in primary tumors. The rate of axillary pathologic complete response (Ax-pCR) was significantly higher in patients with a high number of TILs than in patients with a low number of TILs (72.0% versus 17.1%, p < 0.001). In multivariable analysis, a high number of TILs was a significant predictor of Ax-pCR as well as of pCR of the primary tumor after NAC. Importantly, all patients with HER2-positive tumors in the high TILs group showed Ax-pCR on ALND. TILs in pretreatment primary breast cancer had the potential to predict therapeutic efficacy of NAC in patients with clinical node-positive disease.

Fingolimod and tumor-infiltrating lymphocytes in checkpoint-inhibitor treated cancer patients

Immune checkpoint inhibitors (ICIs) are emerging as the new standard of care for treating various metastatic cancers. It is known that effective anti-tumor immune responses are associated with a stronger presence of tumor-infiltrating lymphocytes (TILs) in solid tumor tissue. Cancer patients with relapsing–remitting multiple sclerosis (RRMS) are often under continuous treatment with fingolimod, an immune-modulating drug that inhibits lymphocyte egress from secondary lymphatic organs. Little is known about the effect of fingolimod on ICI cancer therapy, as fingolimod may limit the number of TILs. Here we present three patients with RRMS, who developed various cancers during fingolimod treatment. Histology of all tumors consistently showed low numbers of TILs. A second biopsy taken from one of the tumors, a melanoma, revealed a significant increase of TILs after stopping fingolimod and starting pembrolizumab, indicating a surge in the number and re-invigoration of T cells. Our study suggests that fingolimod limits the number of TILs in solid tumors and may, thus, inhibit anti-cancer immune responses.

Abstract 5026: Efficacy of anti-PD-1, IDO inhibitor, chemotherapy and bone-targeting agent on tumor growth in a syngeneic bone metastasis model of triple-negative breast cancer

Abstract Triple-negative breast cancer (TNBC) is an aggressive cancer with treatment options limited to standard-of-care chemotherapy. TNBC patients develop metastases in high incidence, and almost all patients have bone metastases at end-stage disease. Bone metastases are mainly osteolytic, causing severe bone loss that can be prevented by bone-targeting agents. Currently, there is no efficient cure for bone metastases. Activation of the patient’s own immune system by immunotherapies is widely studied in various cancers, but their efficacy on bone metastases is not well established. In this study, we aimed to evaluate the efficacy of immunotherapies in comparison to standard-of-care compounds in a preclinical TNBC bone metastasis model. Mouse 4T1-GFP TNBC cells were inoculated intracardially to immunocompetent female Balb/c mice to model bone metastasis. Treatment of single agents of chemotherapy (cyclophosphamide, 100 mg/kg), bone-targeting agent (zoledronic acid, 0.1 mg/kg), and immunotherapies programmed cell death 1 antibody (mouse anti-PD-1, 10 mg/kg) and indoleamine-pyrrole 2,3-dioxygenase (IDO) inhibitor (epacadostat, 100 mg/kg), and the combination of anti-PD-1 and epacadostat were started on the day following the cancer cell inoculations. The study was terminated about 2 weeks after the inoculations. Tumor burden was evaluated at sacrifice by GFP imaging in skeleton and soft tissues, and tumor-induced bone loss by X-ray imaging. Tumor infiltrating lymphocytes (TILs) were evaluated by immunohistochemical stainings of CD3+, CD4+ and CD8+ T cells. Cyclophosphamide decreased skeletal tumor burden and the area of tumor-induced osteolytic bone lesions. It also decreased the number of soft tissue metastases in ovaries and adrenal glands. Zoledronic acid decreased osteolytic lesion area but had no effect on tumor burden. Anti-PD-1, epacadostat and their combination had no effect on tumor burden, on the development of osteolytic lesions, or on the number of soft tissue metastases. Low number or no TILs were observed in the tumors growing in bone obtained from vehicle-treated mice. Immunotherapies did not prevent tumor growth in bone or tumor-induced bone changes in the syngeneic TNBC model. This is probably a consequence of the low number of TILs in the tumors growing in bone. Further studies are needed to evaluate the effects of treatment combinations and to increase the responsiveness to immunotherapies especially in bone metastases. Citation Format: Tiina Emilia Kähkönen, Mari I. Suominen, Jenni H. Mäki-Jouppila, Jussi M. Halleen, Jenni Bernoulli. Efficacy of anti-PD-1, IDO inhibitor, chemotherapy and bone-targeting agent on tumor growth in a syngeneic bone metastasis model of triple-negative breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5026.

Prediction of Benefit from Checkpoint Inhibitors in Mismatch Repair Deficient Metastatic Colorectal Cancer: Role of Tumor Infiltrating Lymphocytes.

Immunotherapy with immune checkpoint inhibitors (ICIs) is highly effective in microsatellite instability-high (MSI-H) metastatic colorectal cancer (mCRC); however, specific predictive biomarkers are lacking. Data and samples from 85 patients with MSI-H mCRC treated with ICIs were gathered. Tumor infiltrating lymphocytes (TILs) and tumor mutational burden (TMB) were analyzed in an exploratory cohort of "super" responders and "clearly" refractory patients; TILs were then evaluated in the whole cohort of patients. Primary objectives were the correlation between the number of TILs and TMB and their role as biomarkers of ICI efficacy. Main endpoints included response rate (RR), progression-free survival (PFS), and overall survival (OS). In the exploratory cohort, an increasing number of TILs correlated to higher TMB (Pearson's test, p = .0429). In the whole cohort, median number of TILs was 3.6 in responders compared with 1.8 in nonresponders (Mann-Whitney test, p = .0448). RR was 70.6% in patients with high number of TILs (TILs-H) compared with 42.9% in patients with low number of TILs (odds ratio = 3.20, p = .0291). Survival outcomes differed significantly in favor of TILs-H (PFS: hazard ratio [HR] = 0.42, p = .0278; OS: HR = 0.41, p = .0463). A significant correlation between higher TMB and increased number of TILs was shown. A significantly higher activity and better PFS and OS with ICI in MSI-H mCRC were reported in cases with high number of TILs, thus supporting further studies of TIL count as predictive biomarker of ICI efficacy. Microsatellite instability is the result of mismatch repair protein deficiency, caused by germline mutations or somatic modifications in mismatch repair genes. In metastatic colorectal cancer (mCRC), immunotherapy (with immune checkpoint inhibitors [ICIs]) demonstrated remarkable clinical benefit in microsatellite instability-high (MSI-H) patients. ICI primary resistance has been observed in approximately 25% of patients with MSI-H mCRC, underlining the need for predictive biomarkers. In this study, tumor mutational burden (TMB) and tumor infiltrating lymphocyte (TIL) analyses were performed in an exploratory cohort of patients with MSI-H mCRC treated with ICIs, demonstrating a significant correlation between higher TMB and increased number of TILs. Results also demonstrated a significant correlation between high number of TILs and clinical responses and survival benefit in a large data set of patients with MSI-H mCRC treated with ICI. TMB and TILs could represent predictive biomarkers of ICI efficacy in MSI-H mCRC and should be incorporated in future trials testing checkpoint inhibitors in colorectal cancer.

Abstract B144: Lack of immunotherapy efficacy in a syngeneic bone metastasis model of triple-negative breast cancer

Abstract Background: Triple-negative breast cancer (TNBC) is an aggressive cancer with treatment options limited to standard-of-care chemotherapy. TNBC patients develop metastases in high incidence, and almost all patients have bone metastases at end-stage disease. Bone metastases are mainly osteolytic, causing severe bone loss that can be prevented by bone-targeted agents. Currently, there is no efficient cure for bone metastases. Activation of the patient’s own immune system by immunotherapies is widely studied in various cancers, but their efficacy on bone metastases is not well established. In this study, we aimed to evaluate the efficacy of immunotherapies in comparison to standard-of-care compounds in a preclinical TNBC bone metastasis model. Materials and methods: Mouse 4T1-GFP TNBC cells were inoculated intracardially to immunocompetent female Balb/c mice to model bone metastasis. Treatment of single agents of chemotherapy (cyclophosphamide, 100 mg/kg), bone-targeting agent (zoledronic acid, 0.1 mg/kg), and immunotherapies programmed cell death 1 antibody (mouse anti-PD-1, 10 mg/kg) and indoleamine-pyrrole 2,3-dioxygenase (IDO) inhibitor (epacadostat, 100 mg/kg), and the combination of anti-PD-1 and epacadostat were started on the day following the cancer cell inoculations. The study was terminated 12-13 days after the inoculations. Tumor burden was evaluated by GFP imaging and tumor-induced bone loss by X-ray imaging at sacrifice. Tumor infiltrating lymphocytes (TILs) were evaluated by immunohistochemical stainings of CD3+, CD4+ and CD8+ T cells. Results: Cyclophosphamide decreased skeletal tumor burden and the area of tumor-induced osteolytic bone lesions. Zoledronic acid decreased the area of osteolytic lesions but had no effect on skeletal tumor burden. Anti-PD-1, epacadostat and their combination had no effect on skeletal tumor burden or in the development of osteolytic lesions. Low number or no TILs were observed in the tumors growing in bone obtained from vehicle-treated mice. Conclusions: Immunotherapies did not prevent tumor growth in bone or tumor-induced bone changes in the syngeneic TNBC model. This is probably caused by the low number of TILs in the tumors growing in bone. Further studies are needed to evaluate the effects of treatment combinations and to increase the responsiveness to immunotherapies especially in bone metastases. Citation Format: Tiina E Kähkönen, Mari I Suominen, Jenni HE Mäki-Jouppila, Jussi M Halleen, Jenni Bernoulli. Lack of immunotherapy efficacy in a syngeneic bone metastasis model of triple-negative breast cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B144. doi:10.1158/1535-7163.TARG-19-B144

Human Immune System Increases Breast Cancer-Induced Osteoblastic Bone Growth in a Humanized Mouse Model without Affecting Normal Bone.

Bone metastases are prevalent in many common cancers such as breast, prostate, and lung cancers, and novel therapies for treating bone metastases are needed. Human immune system-engrafted models are used in immuno-oncology (IO) studies for subcutaneous cancer cell or patient-derived xenograft implantations that mimic primary tumor growth. Novel efficacy models for IO compounds on bone metastases need to be established. The study was performed using CIEA NOG (NOG) mice engrafted with human CD34+ hematopoietic stem cells (huNOG) and age-matched immunodeficient NOG mice. Bone phenotyping was performed to evaluate baseline differences. BT-474 human breast cancer cells were inoculated into the tibia bone marrow, and cancer-induced bone changes were monitored by X-ray imaging. Bone content and volume were analyzed by dual X-ray absorptiometry and microcomputed tomography. Tumor-infiltrating lymphocytes (TILs) and the expression of immune checkpoint markers were analyzed by immunohistochemistry. Bone phenotyping showed no differences in bone architecture or volume of the healthy bones in huNOG and NOG mice, but the bone marrow fat was absent in huNOG mice. Fibrotic areas were observed in the bone marrow of some huNOG mice. BT-474 tumors induced osteoblastic bone growth. Bone lesions appeared earlier and were larger, and bone mineral density was higher in huNOG mice. huNOG mice had a high number of human CD3-, CD4-, and CD8-positive T cells and CD20-positive B cells in immune-related organs. A low number of TILs and PD-1-positive cells and low PD-L1 expression were observed in the BT-474 tumors at the endpoint. This study reports characterization of the first breast cancer bone growth model in huNOG mice. BT-474 tumors represent a “cold” tumor with a low number of TILs. This model can be used for evaluating the efficacy of combination treatments of IO therapies with immune-stimulatory compounds or therapeutic approaches on bone metastatic breast cancer.

Abstract B016: Automated ex vivo expansion of low numbers of tumor-reactive T-cells on the CliniMACS Prodigy®

Abstract Adoptive cell transfer (ACT) of tumor-infiltrating lymphocytes (TILs) has shown remarkable results in patients with metastatic melanoma. However, only a small fraction within the TIL population reacts against the tumor. Therefore, the pre-enrichment of tumor-specific T-cells and subsequent ex vivo expansion may improve the efficiency of ACT therapies. In addition, tumor-reactive T lymphocytes circulating in the blood (TRLs) have been found in low frequencies, which represents a challenge for their isolation, but also an advantage over TIL therapy since blood is a more reliable and accessible source than tumor excisions. Another impediment to the widespread application of ACT is the conventional rapid expansion protocol (REP) that constitutes a laborious and extensive process with frequent culture manipulations, and thus requires specialized personell and equipment. Our aim is to develop a fully automated large scale ex vivo T-cell isolation and expansion procedure in the CliniMACS Prodigy in order to simplify the manufacturing of tumor-reactive T-cells for ACT. The CliniMACS Prodigy instrument is a controlled system that integrates a series of cell processes, from magnetic cell separation and cell culture to final product formulation, under GMP conditions in a closed system. This process focuses on the optimization of the REP procedure on the CliniMACS Prodigy for TILs and TRLs. As a proof of concept, we used both cryopreserved outgrown TILs and magnetically isolated virus-specific T-cells from healthy donor leukapheresis via CD137 upregulation upon in vitro antigen stimulation. The first results show expansions ranging from 3,000-15,000 fold, both for TILs and CD137-expressing T-cells. From low cell numbers (2x10e5 - 1x10e6 cells) and after 14 days of cell culture in TexMACS medium and in the presence of high amounts of IL-2 and irradiated feeder cells, we were able to obtain around 3-4x10e9 cells. We also compared two different stimulation reagents, anti-CD3 antibody (OKT3) and TransAct (a soluble polymeric nanomatrix conjugated to humanized CD3 and CD28 agonist), which resulted in comparable expansion rates. Furthermore, small-scale experiments showed no differences between TexMACS and the conventional TIL culture medium (50% RPMI/50% AIM-V medium). The phenotype and reactivity of the expanded T-cells were also assessed by flow cytometry. Currently, higher starting cell numbers up to 1x10e7 cells are being assessed and first results are promising when shaking and media exchange are commenced earlier in the process. In summary, these data provide proof of concept for the expansion of low numbers of TILs and virus-specific T-cells from peripheral blood in a closed, automated manner in the CliniMACS Prodigy. In the future, this expansion process will be combined with a tumor-reactive T-cell enrichment process (e.g., via CD137-conjugated magnetic beads) to achieve the desired efficiency, simplicity and automated production of ACT therapies against cancer. Citation Format: Bianca Heemskerk, Christina Maeder, Elvira Criado-Moronati, Lisa Boettcher, Andrew Kaiser, Mario Assenmacher, Andrzej Dzionek. Automated ex vivo expansion of low numbers of tumor-reactive T-cells on the CliniMACS Prodigy® [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr B016.

Possibility of avoiding axillary lymph node dissection by immune microenvironment monitoring in preoperative chemotherapy for breast cancer

BackgroundThe diagnosis of metastasis by sentinel lymph node biopsy (SLNB) in early breast cancer surgery provides an accurate view of the state of metastases to the axillary lymph nodes, and it has now become the standard procedure. In the present study, whether omission of axillary lymph node dissection (ALND) after neoadjuvant chemotherapy (NAC) is possible by evaluation of tumor-infiltrating lymphocytes (TILs) before NAC in cases without metastasis on diagnostic imaging, but with metastasis on SLNB, was retrospectively investigated.MethodsA total of 91 patients with resectable, early-stage breast cancer, diagnosed as cT1–2, N0, M0, underwent SLNB and were treated with NAC. A semi-quantitative evaluation of lymphocytes infiltrating the peritumoral stroma as TILs in biopsy specimens of primary tumors prior to treatment was conducted.ResultsIn cases with a low number of TILs, estrogen receptor expression was significantly higher (p = 0.044), and human epidermal growth factor receptor 2 (HER2) expression was significantly lower than in other cases (p = 0.019). The number of TILs was significantly lower in cases in which the intrinsic subtype was hormone receptor-positive breast cancer (HRBC) (p = 0.044). Metastasis to axillary lymph nodes was significantly more common in HER2-negative cases and cases with a low number of TILs (p = 0.019, p = 0.005, respectively).ConclusionsEven if macrometastases are found on SLNB in cN0 patients, it appears that ALND could be avoided after NAC in cases with a good immune tumor microenvironment of the primary tumor.

Radiation Therapy Combined with Cowpea Mosaic Virus Nanoparticle in Situ Vaccination Initiates Immune-Mediated Tumor Regression.

Epithelial ovarian cancer is a deadly gynecologic malignancy because of its late detection, usually after local and distant metastatic spread. These cancers develop resistance to traditional chemotherapeutic agents; therefore, the development of next-generation immunotherapeutic approaches may have a significant promise in improving outcomes. A novel immunotherapeutic approach utilizing combination radiation therapy (RT) with immunostimulatory cowpea mosaic virus (CPMV) was tested in a preclinical syngeneic mouse model of ovarian carcinoma. ID8-Defb29/Vegf tumors were generated in C57BL/6 mice. Compared to placebo-treated control tumors or those treated with a single agent RT or CPMV, the combination treatment resulted in a significantly improved tumor growth delay (p < 0.05). Additionally, immunohistochemical profiling of tumor samples after treatment with CPMV demonstrated an increase in tumor infiltrating lymphocytes (TILs). These results suggest that utilizing CPMV particles in combination with RT can turn an immunologically “cold” tumor (with low number of TILs) into an immunologically “hot” tumor. This novel combination treatment approach of RT and CPMV demonstrated the ability to control tumor growth in a preclinical ID8 ovarian cancer model, showing promise as an in situ tumor vaccine and warrants further testing.

Exam 4: Regular Aspirin Use Associates With Lower Risk of Colorectal Cancers With Low Numbers of Tumor-Infiltrating Lymphocytes

Exam 4: Regular Aspirin Use Associates With Lower Risk of Colorectal Cancers With Low Numbers of Tumor-Infiltrating Lymphocytes

Regular Aspirin Use Associates With Lower Risk of Colorectal Cancers With Low Numbers of Tumor-Infiltrating Lymphocytes

Aspirin use reduces colorectal cancerrisk. Aspirin, a nonsteroidal anti-inflammatory drug, inhibits prostaglandin-endoperoxide synthase 2 (PTGS2 or cyclooxygenase-2); PTGS2 promotes inflammation and suppresses T-cell-mediated adaptive immunity. We investigated whether the inverse association of aspirin use with colorectal carcinoma risk was stronger for tumors with lower degrees of lymphocytic infiltrates than for tumors with higher degrees of lymphocytic infiltrates. We collected aspirin use data biennially from participants in the Nurses' Health Study and Health Professionals Follow-up Study. Participants were asked whether they took aspirin in most weeks, the number of tablets taken per week, and years of aspirin use. We collected available tumor specimens (n= 1458) from pathology laboratories in the United States. A pathologist confirmed the diagnosis of colorectal adenocarcinoma (excluding anal squamous cell carcinoma), and evaluated histopathology features, including patterns and degrees of lymphocytic infiltrates within and around tumor areas. Person-years of follow-up evaluation were accrued from the date of return of questionnaires until dates of colorectal cancer diagnosis, death, or the end of follow-up evaluation (June 2010). Duplication-method Cox proportional hazards regression was used to assess the association of aspirin with the incidence of colorectal carcinoma subgroups according to the degree of tumor-infiltrating lymphocytes (TILs), intratumoral periglandular reaction, peritumoral reaction, or Crohn's-like reaction. We documented 1458 rectal and colon cancers. The inverse association between regular aspirin use and colorectal cancer risk significantly differed by concentrations of TILs (Pheterogeneity= .007). Compared with nonregular use, regular aspirin use was associated with a lower risk of tumors that had low levels of TILs (relative risk, 0.72; 95% confidence interval, 0.63-0.81), and strength of the association depended on aspirin dose and duration (both Ptrend < .001). In contrast, aspirin use was not associated with a risk of tumors having intermediate or high levels of TILs. This differential association was consistent regardless of the status of tumor microsatellite instability, mutations in BRAF, or expression of PTGS2. Regular aspirin use was associated with a lower risk of tumors that contained low levels of CD3+ Tcells, CD8+ T cells, or CD45RO (PTPRC)+ T cells (measured by immunohistochemistry and computer-assisted image analysis). Based on data from the prospective cohort studies, regular use of aspirin is associated witha lower risk of colorectal carcinomas with low concentrations of TILs. These findings indicate that the immune response in thetumor microenvironment could be involved in the chemopreventive effects of aspirin.

Association and prognostic significance of BRCA1/2-mutation status with neoantigen load, number of tumor-infiltrating lymphocytes and expression of PD-1/PD-L1 in high grade serous ovarian cancer.

Immune checkpoint inhibitors (e.g., anti-PD-1 and anti-PD-L1 antibodies) have demonstrated remarkable efficacy against hypermutated cancers such as melanomas and lung carcinomas. One explanation for this effect is that hypermutated lesions harbor more tumor-specific neoantigens that stimulate recruitment of an increased number of tumor-infiltrating lymphocytes (TILs), which is counterbalanced by overexpression of immune checkpoints such as PD-1 or PD-L1. Given that BRCA1/2-mutated high grade serous ovarian cancers (HGSOCs) exhibit a higher mutational load and a unique mutational signature with an elevated number of larger indels up to 50 bp, we hypothesized that they may also harbor more tumor-specific neoantigens, and, therefore, exhibit increased TILs and PD-1/PD-L1 expression. Here, we report significantly higher predicted neoantigens in BRCA1/2-mutated tumors compared to tumors without alterations in homologous recombination (HR) genes (HR-proficient tumors). Tumors with higher neoantigen load were associated with improved overall survival and higher expression of immune genes associated with tumor cytotoxicity such as genes of the TCR, the IFN-gamma and the TNFR pathways. Furthermore, immunohistochemistry studies demonstrated that BRCA1/2-mutated tumors exhibited significantly increased CD3+ and CD8+ TILs, as well as elevated expression of PD-1 and PD-L1 in tumor-associated immune cells compared to HR-proficient tumors. Survival analysis showed that both BRCA1/2-mutation status and number of TILs were independently associated with outcome. Of note, two distinct groups of HGSOCs, one with very poor prognosis (HR proficient with low number of TILs) and one with very good prognosis (BRCA1/2-mutated tumors with high number of TILs) were defined. These findings support a link between BRCA1/2-mutation status, immunogenicity and survival, and suggesting that BRCA1/2-mutated HGSOCs may be more sensitive to PD-1/PD-L1 inhibitors compared to HR-proficient HGSOCs.