Browsing Over 91 Presentations
15P - Tumour PD-L1 expression and blood biomarkers of activity of adaptive immunity and tumour microenvironment in patients with solid tumours
- Anna Malkova (Saint-Petersburg, Russian Federation)
- Anna Malkova (Saint-Petersburg, Russian Federation)
- Rashida Orlova (Saint-Petersburg, Russian Federation)
- Natalia Zhukova (Saint-Petersburg, Russian Federation)
- Vladimir Sharoyko (Saint-Petersburg, Russian Federation)
- Ekaterina Kaledina (Saint-Petersburg, Russian Federation)
Abstract
Background
Tumor PD-L1 overexpression leads to suppression of cytotoxic adaptive immunity. Recently high level of Interleukin-1 beta (IL-1β) in the tumor microenvironment (TME) was reported to be associated with immunosuppression of lymphocytes. The ratio of neutrophils and lymphocytes (NLR) in the tumor tissue and in the peripheral blood reflects the activity of adaptive immunity. The aim of this work is to study the relationship between the tumor expression of the PD-L1, the concentration of serum IL-1β, a possible marker of TME activity, and NLR, a marker of adaptive immunity activity.
Methods
The serum samples of patients with various solid tumors (n=48) before the start of checkpoint inhibitors therapy were collected. The serum level of IL-1-β was measured with ELISA (\"ELISA-best\", Novosibirsk, Russia), tumor PD-L1 expression was determined by immunohistochemical method, a full blood count by cytometry. The results obtained were analyzed in GraphPad Prism 6 (Graph Pad Software, USA) using Fisher, Mann-Whitney, and Spearman's statistical analysis. The project is supported by grant (contract №20-015-00498/20).
Results
Positive PD-L1 expression was observed in 72,92% (35/48) of the patients, while IL-1β was detected in 66,67% (32/48) and high NLR was registered in 35,42% (17/48). The tumor PD-L1 expression had a positive statistically significant low correlation with serum IL-1β concentration (r=0,327; p=0,037) and the NLR (r=0,327; p = 0,034). IL-1β level was positively correlated with NLR (r= 0,353; p= 0,025). In a group with positive PD-L1 expression the mean concentration of IL-1β was 1,65± 0,54 pg/ml, the mean NLR was 4,26±0,94 109/L, what exceeds the meanings of the group with negative expression, but without statistical significance.
Conclusions
The study revealed a positive correlation between the tumor PD-L1 expression, the serum IL-1β concentration and the NLR. The obtained result may indicate the influence of the immunosuppressive properties of the tumor on the state of the patient's immunity. A comprehensive determination of tumor PD-L1 expression, serum IL-1β concentration and NLR can be used as an assessment of the patient's immune status before starting treatment with checkpoint inhibitors.
Legal entity responsible for the study
The authors.
Funding
Russian Foundation for Basic Research (RFBR) - Project number 20-015-0049820 of 19.02.2020.
Disclosure
All authors have declared no conflicts of interest.
16P - PD-1/PD-L1 expression in uveal melanoma: Prognostic significance with tumour-infiltrating lymphocytes and clinicopathological parameters
- Lata Singh (New Delhi, India)
- Lata Singh (New Delhi, India)
- Mithalesh Singh (Madison, WI, United States of America)
- Moshahid Rizvi (New Delhi, India)
- Seema Kashyap (New Delhi, India)
Abstract
Background
In order to understand how to improve the effect of immune checkpoint inhibitors in uveal melanoma (UM), we need a better understanding of the expression of PD-1 and PD-L1, their relation with or without the presence of tumor-infiltrating lymphocytes (TILs), and their prognostic relevance in UM patients.
Methods
Expression of PD-1 and PD-L1 was assessed in 71 UM tissue samples by immunohistochemistry and quantitative real-time PCR (qRT-PCR), and further validated by western blotting. Hazard ratios and their 95% confidence intervals (CI) were noted for each parameter and independent prognostic factors were identified by univariate and multivariate analysis through Cox proportional-hazards models.
Results
Immunoreactivity of PD-1 was found in 30/71 cases and of PD-L1 in 44/71 UM samples. Tumor-infiltrating lymphocytes were found in 46% of UM tissues. PD-1 was expressed on TILs while tumor cells expressed PD-L1. UM with and without TILs showed expression of PD-1 in 69% and 18% cases, respectively (p=0.001). Similarly, PD-L1 was found in 75% of UM with TILs and in 50% of cases without TILs, respectively (p=0.03). DFS rate were lower in patients with TILs with positive immunoreactivity and mRNA expression of PD-1 and PD-L1 but the rate of DFS was seen significantly better in patients with expression of PD-L1 in patients without TILs.
Conclusions
To conclude, TILs play an important immune cell for achieving successful immunotherapeutic strategies in the treatment of UM patients. Our finding suggests that PD-1 and PD-L1 expression in TILs showed poor outcome that helps in identifying a subgroup of UM patients who may benefit from immunotherapy.
Legal entity responsible for the study
The authors.
Funding
N-PDF SERB-DST.
Disclosure
All authors have declared no conflicts of interest.
17P - Effects of tumour mutation burden on the antigen presentation pathway
- Enrique Garcia-Rivera (Rochester, MN, United States of America)
- Enrique Garcia-Rivera (Rochester, MN, United States of America)
- Jiho Park (Rochester, MN, United States of America)
- Caroline Truntzer (Dijon, France)
- François Ghiringhelli (Dijon, France)
- Aaron Mansfield (Rochester, MN, United States of America)
Abstract
Background
Tumor mutation burden (TMB) can be a predictor of benefit from treatment with immune checkpoint inhibitors (ICIs); however, some patients whose tumors have high TMBs do not benefit from treatment with ICIs. Loss of beta2-microglobulin (B2M) is a mechanism of acquired resistance to ICIs. We hypothesized that a potential mechanism of inherent resistance to ICIs is the inactivation of B2M and other antigen presenting genes (APGs) resulting from increasing TMBs.
Methods
We identified APGs by expert selection and use of the nferX knowledge synthesis platform. We profiled 9,418 tumors of 33 types in TCGA for somatic mutations and their involvement with APGs. Cohen’s d was used to determine the effect of TMB on mutations in APGs. Whole exome sequencing results from 62 patients with non-small cell lung cancer (NSCLC) treated with nivolumab in second or later lines of therapy were evaluated to determine the effect of mutations in APGs on survival using the log-rank test (Dijon Cohort).
Results
In TCGA, mutations in APGs were associated with increasing TMBs across 33 solid tumors (Cohen’s d=0.731, t-test p=8.476 × 10-199), and specifically in lung adenocarcinoma (n=508, Cohen’s d=0.552, t-test p=8.726 × 10-10). In non-small cell lung cancer (NSCLC) adenocarcinomas, ITGAX and CD1B were some of the most commonly mutated APGs (respectively 8.66%, Cohen’s d=1.132, t-test p-value=5.484 × 10-13; 2.56%, Cohen’s d=1.10, t-test p=2.150 × 10-5). In the Dijon Cohort, there was a mild association of increased TMB with mutations in APGs (Cohen’s d=0.870, t-test p=0.002). Mutations in one or more APGs were associated with improved progression-free survival (PFS; HR=0.54, log rank test p-value=0.04) but not overall survival (HR=0.78, log rank test p=0.49).
Conclusions
Increasing TMBs are strongly associated with mutations in genes essential to antigen presentation, specifically including ITGAX and CD1B in NSCLC. Contrary to our hypothesis, mutations in APGs were associated with improved PFS with nivolumab, possibly due to the involvement of single alleles rather than complete loss. Although bi-allelic loss of APGs may be a mechanism of inherent resistance to ICIs, mutations in these genes may more commonly serve as a surrogate for high TMBs and potential benefit of treatment with PD-1 inhibitors in NSCLC.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
J. Park: Full/Part-time employment: nference. F. Ghiringhelli: Honoraria (institution), Oral Communication: Lilly, Sanofi & Amgen; Honoraria (institution), Advisory Board: Merck Serano, Amgen, Sanofi. A.S. Mansfield: Honoraria (institution), Advisory Board: AbbVie; Honoraria (institution), Advisory Board: AstraZeneca; Honoraria (institution), Advisory Board: BMS; Honoraria (institution), Travel/Accommodation/Expenses, Advisory Board: Genentech/Roche; Research grant/Funding (institution): Novartis; Research grant/Funding (institution): Verily; Leadership role, Non-Renumerated Director: Mesothelioma Applied Research Foundation. All other authors have declared no conflicts of interest.
18P - Influence of local immunity on the prognosis of gastric cancer
- Gulnoz Khakimova (Tashkent, Uzbekistan)
- Gulnoz Khakimova (Tashkent, Uzbekistan)
Abstract
Background
Gastric cancer (GC) takes 5th place among oncology diseases (1,313,000 cases) and 3rd cause of cancer mortality (819,000 deaths) in the world. The cells of the immune system play a key role in the concept of “antitumor immunity”. The variety of subpopulations of these cells, products of their synthesis and pathways of interaction can explain their possible diametrically opposite action: from mechanisms of antitumor protection to stimulation of carcinogenesis. Aim: To study the state of local immunity in patients with gastric cancer.
Methods
From 2017 to 2018, 45 previously untreated patients with gastric adenocarcinoma (25 with stage I–III, 20 with stage IV) received surgical/combined treatment or chemotherapy, respectively. Tumor tissue was taken before treatment. By using flow cytometry there were evaluated the percentage of tumor tissue infiltration by lymphocytes (CD45+CD14-TIL); T cells (CD3+CD19-TIL); B cells (CD3-CD19+TIL); NK cell (CD3- CD16+CD56+TIL); effector cells CD16 (CD16+Perforin+TIL) and CD8 (CD8+Perforin+TIL) with their cytotoxic potential – active CD16TIL and active CD8TIL; subpopulations of regulatory T cells – NKT cells (CD3+CD16+CD56+TIL), regulatory cells CD4 (CD4+CD25+CD127-TIL) and CD8 (CD8+CD11b-CD28-TIL). The prognostic value of immune cells for overall survival (OS) and progression-free survival (PFS) was assessed.
Results
A favorable prognosis factor for PFS in patients with local and locally advanced forms of gastric cancer was an increase in the number of CD3-CD19+TIL (HR 0.862, 95% CI 0.782–0.957, p=0.005), and an unfavorable prognosis was an increase in NK cells; HR 1.382, 95% CI 1.087–1.758, p=0.008. The negative effect of the relative content of NK cells and NKT cells on OS of patients with metastatic gastric cancer noted (HR 1.249, 95% CI 0.997–1.564, p=0.053; HR 1.127, 95% CI 1.025–1.239, p=0.013). At the same time, an increase in the percentage of tumor tissue infiltration by lymphocytes and an increase in the age of patients (HR 1.005, 95% CI 1.002–1.008, p=0.003; HR 1.098, 95% CI 1.031–1.170, p=0.004) reduce the incidence of PFS in patients with metastatic gastric cancer.
Conclusions
Indices of local immunity can serve as additional prognostic factors for gastric carcinoma.
Legal entity responsible for the study
Tashkent City Oncology Center.
Funding
Has not received any funding.
Disclosure
The author has declared no conflicts of interest.
19P - Tumour microenvironment and radiomics landscape associated with survival and prediction of immunotherapy in patients with cancer
- Wenda Zhang (Zhanjiang, China)
- Wenda Zhang (Zhanjiang, China)
- Anlin Li (Zhanjiang, China)
- Yongjian Chen (Guangzhou, China)
- Qiyun Ou (Guangzhou, China)
- Wei Ren (Guangzhou, China)
Abstract
Background
Immunotherapies provide significant survival benefits in many cancers, but the association of tumor microenvironment (TME) with clinical outcomes of immunotherapy remains to be explored. We aim to utilize comprehensive profile of TME-related components and molecular mechanisms to accurately predict the cancer immunotherapy benefit, and further evaluate the predictive utility of the combination of TME and radiomics landscape.
Methods
This study analyzed RNA sequencing or whole-exome data of 3,663 patients treated with immunotherapy from the phase II IMvigor210 trial, Gene Expression Omnibus and cBioPortal database, and of 4,547 patients from The Cancer Genome Atlas. We built a novel predictive TME score integrating immune checkpoints, human leukocyte antigens, immune cells, long non-coding RNA, and tumor mutation burden using computational algorithms, and further combined it with radiomics landscape.
Results
The analysis of IMvigor210 trial identified that patients with high TME scores had strikingly greater overall survival (OS) benefits from immunotherapy compared with patients with low TME scores (hazard ratio 0.41, 95% CI, 0.30 to 0.57; P < 0.0001). The TME score showed encouraging immunotherapeutic predictive ability for OS (20-month, AUC = 0.81) and response (AUC = 0.77). These findings were successfully validated in other cohorts across multiple cancer types. Moreover, the combination of TME score and radiomics landscape was superior to the variable alone in predicting the patient prognosis for OS (AUC = 0.91, 0.87, 0.75 for the combination, TME score and radiomics landscape, respectively).
Conclusions
This study developed a TME score that achieved accurate prediction of immunotherapy benefit in patients with cancer. The study is also the first to highlight that the combination of TME signature and radiomics landscape has predictive implications for immunotherapy and merits prospective validation in future clinical trials.
Legal entity responsible for the study
Herui Yao.
Funding
National Science and Technology Major Project (2020ZX09201021), Medical Artificial Intelligence Project of Sun Yat-Sen Memorial Hospital (YXRGZN201902), National Natural Science Foundation of China (81572596, 81972471, U1601223), Natural Science Foundation of Guangdong Province (2017A030313828), Guangzhou Science and Technology Major Program (201704020131), Guangdong Science and Technology Department (2017B030314026), Special Funds for the Cultivation of Guangdong College Students’ Scientific and Technological Innovation (PDJH2019A0212), National Students’ Innovation and Entrepreneurship Training Program (201910571001), Guangdong Medical University College Students’ Innovation Experiment Project (ZZZF001).
Disclosure
All authors have declared no conflicts of interest.
20P - Quantitative whole slide assessment of CD8+ tumour-infiltrating lymphocytes in small cell esophageal carcinoma in relation to clinical outcome
- Zhihui Zhang (Beijing, China)
- Zhihui Zhang (Beijing, China)
- Chaoqi Zhang (Beijing, China)
- Guochao Zhang (Beijing, China)
- Liyang Xue (Beijing, China)
- Qingpeng Zeng (Beijing, China)
Abstract
Background
Primary small cell esophageal carcinoma (SCEC) represents a rapidly progressive, aggressive, and rare malignancy without any established treatment strategy. Given the great success of cancer immunotherapy targeting the PD-1/PD-L1 pathway in small cell lung cancer and the central role of CD8+ tumor-infiltrating lymphocytes (TIL) in the response to immune checkpoint inhibitors, we set out to assess the expression pattern and clinical significance of CD8+ TIL in SCESs for the first time.
Methods
Totally, 147 SCEC patients underwent surgery at our institution between 1985 and 2019 were collected. The formalin-fixed paraffin-embedded whole tumor sections were immunostained for CD8 with monoclonal mouse antibody. Whole-slide scanning was performed and the tumor regions were annotated by a trained gastrointestinal pathologist. The digital image analysis was then performed to quantify the CD8+ TILs density. Baseline clinicopathological features and outcome data (relapse free survival (RFS) and overall survival (OS)) were correlated with CD8+ TIL states.
Results
The median number of CD8+ TIL cells in SCECs was 111.1 cells/mm2, with the range of 7.5 to 1458.6 cells/mm2. The mean destiny (195.9 cells/mm2) was used as cut-off value stratifying CD8+ TIL positive or negative groups. Positive CD8+ TILs infiltration was found significantly related to macroscopic tumor type (P=0.006), T stage (P=0.007) and TNM stage (P=0.005). Kaplan–Meier analysis showed that patients with positive CD8+ TILs state showed dramatically better RFS (HR = 0.456, 95% CI 0.309–0.674, P=0.0004) and OS (HR = 0.423, 95% CI 0.273–0.657, P=0.0008). Univariate and multivariate Cox regression analyses confirmed that CD8+ TIL state was the significant independent predictor for both RFS and OS, with P values of 0.0140 and 0.0457, respectively.
Conclusions
Here, for the first, we demonstrated that CD8+ TIL destiny was associated with an early stage and favorable clinical outcome in SCECs, supporting its role as a prognostic biomarker. These findings will not only help to improve risk-adapted therapeutic strategies, but also provide a rational basis for further investigation of PD-L1/PD-1-based immunotherapy for patients with SCECs.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
21P - Characteristics of the lymphocytic infiltrate in breast cancer
- Wala Ben Kridis (Sfax, Tunisia)
- Wala Ben Kridis (Sfax, Tunisia)
- Lobna Bouzidi (Sfax, Tunisia)
- Slim Charfi (Sfax, Tunisia)
- Hana Triki (Sfax, Tunisia)
- Boutheina Cherif (Sfax, Tunisia)
Abstract
Background
The impact of lymphocytic infiltrate is well demonstrated in breast cancers. The study of the NK cell population is poorly documented with discordant results. This study aims to evaluate the degree of lymphocytic infiltrate and CD56 + NK cell infiltrate as well as their correlations with clinicopathological factors and with survival.
Methods
This is a retrospective study of breast cancer cases collected in Habib Bourguiba Hospital in Sfax. CD56 expression was assessed by a immunohistochemical method.
Results
There were 119 cases of breast carcinoma. Quantification of TIL's was performed in 113 patients. The tumors were classified as low grade in 56 cases (49.5%), medium grade in 17 cases (15.04%) and high grade in 41 cases (35.4%). The predominantly lymphocytic tumors were observed in 23 cases (20.3%). An elevated level of CD56 + cells was observed in 24 cases (21.4%). In univariate analysis, TIL's were associated with the metastatic stage (p = 0.03) without correlation with the other factors. NK-TIL's were associated with young age, high SBR grade, negative hormone receptors, high Ki-67 proliferation index, and molecular class (more common in non-luminal tumors). OS at 5 years was 97% in TIL's high-grade tumor level versus 52% in the low grade tumor group (p <0.001). The OS at 5 years was 88% for tumors with a high level of CD 56+ cells versus 72.5% for tumors with a low level of CD56 + cells (p = 0.042).
Conclusions
Systematic measurement of TIL's for breast cancer is recommended. A high subpopulation of CD56 + cells correlates with better survival.
Legal entity responsible for the study
Habib Bourguiba Committee.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
22P - Dynamics of indicators of the immune status in patients with metastatic solid tumours on the background of stereotactic ablative radiation therapy
- Anton Zozulya (Saint-Petersburg, Russian Federation)
- Anton Zozulya (Saint-Petersburg, Russian Federation)
- Irina Baldueva (Saint-Petersburg, Russian Federation)
- Sergey Novikov (Saint-Petersburg, Russian Federation)
- Dmitriy Girdyuk (Saint-Petersburg, Russian Federation)
- Natalya Emelyanova (Saint-Petersburg, Russian Federation)
Abstract
Background
Stereotactic ablative radiation therapy (SABR) is actively used for treatment of patients with oligometastatic tumor process. It is assumed, that in addition to the direct effect on the tumor site, SABR can enhance the formation of an antitumor immune response. In this regard, the aim of our study is investigation of SABR’s influence on indicators of the immune status in patients with metastatic solid tumors.
Methods
We performed a preliminary analysis of the immunological parameters of blood before irradiation (point A), via 3-4 weeks (point B) and via 6-8 weeks (point C) after SBRT in 29 patients with malignant tumors with oligometastases in the liver and lungs. Radiotherapy was performed on the linear accelerator “Novalis Tx” EX = 6 MeV, all peripheral blood samples (87) were analyzed by flow cytometry on a FACS Canto ™ II cytometer. We used Friedman test for multiple comparison and Nemenyi test for between-group comparison. Data processing and statistical analysis was performed using Microsoft Excel 2010 and R (ver. 4.0.2).
Results
We observed statistically significant increase of T-lymphocytes (CD3+CD19-), χ2 = 13,8, p = 0,001, pairwise p(A, B) = 0,002; T-helpers (CD3+CD4+), χ2 = 8,2, p = 0,017, pairwise p(A, B) = 0,019; activated T-helpers (CD3+CD4+HLA-DR+), χ2 = 30,1; p < 0,001; pairwise p(A, B) < 0,001, p(A, C) < 0.001; activated cytotoxic T lymphocytes (CD3+СD8+HLA-DR+), χ2 = 13,3; p = 0,001; pairwise p(A, B) = 0,003, p(A, C) = 0.007; and decrease of B-lymphocytes (CD3-CD19+), χ2 = 31,5; p < 0,001, pairwise p(A, B) < 0,001, p(A, C) = 0.006. Interesting, that 6-8 weeks after SABR, in comparison with valued obtained 3-4 weeks after SABR, we detected statistically significant decrease of T-lymphocytes (pairwise p(B, C) = 0.01) and increase of B-lymphocytes (pairwise p(B, C) = 0.034).
Conclusions
Thus, revealed dynamics of immunological parameters indicates the induction of the T-cell link of antitumor immunity against decreasing of indicators of humoral immunity.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
25P - Improving efficacy and reducing toxicity of anti-PD-L1 treatment: T-cells as delivery vehicles for anti-PD-L1 blocking nanobodies
- Pierre-florent Petit (Brussels, Belgium)
- Pierre-florent Petit (Brussels, Belgium)
- Jingjing Zhu (Brussels, Belgium)
- Benoit Van den Eynde (Brussels, Belgium)
Abstract
Background
Cancer therapy has experienced a paradigm shift due to the clinical success of immune checkpoint inhibitors (ICI) such as anti-PD-L1 antibodies, yet ICI benefits remain limited to a minority of patients. On top of the resistance mechanisms limiting their efficacy, ICI are causing auto-immune side effects related to the activation of self-directed CD8 T cells. We propose a new approach using antitumoral T cells as vehicles to deliver anti-PD-L1 nanobodies specifically at the tumor site. Compared to antibodies, nanobodies offer the advantage of a good penetration ability in tissues while displaying a very short half-life in the blood stream. We evaluated whether this approach could improve efficacy and reduce toxicity compared to classical anti-PD-L1 antibody treatment.
Methods
Ovalbumin-specific OT-I T cells were engineered to secrete an anti-PD-L1 blocking nanobody. In MC38 Ova murine colon carcinoma model, adoptive transfer of nanobody-secreting T cells was compared with wildtype T cells alone or wildtype T cells in combination with an anti-PD-L1 antibody given by intraperitoneal injection. Treatment efficacy was assessed by measuring tumor growth over time. Flow cytometry and immuno-histochemistry (IHC) analysis on tumor, lymph nodes and spleen samples were performed to compare the distribution of the anti-PD-L1 treatment across different tissues.
Results
Intratumoral delivery of anti-PD-L1 nanobody improved tumor rejection compared to systemically given anti-PD-L1 antibody. According to flow cytometry and IHC analysis, anti-PD-L1 nanobody was enriched in the tumor compared to spleen and lymph nodes, while anti-PD-L1 antibody was rather enriched in spleen and lymph nodes and weakly detected in the tumor. This low systemic exposure to the nanobody could minimize the risk of developing auto-immune side effects.
Conclusions
Our study points out the poor penetration of anti-PD-L1 antibody in established tumors as a limitation factor for its efficacy in treating MC38 Ova tumors. Local delivery of an anti-PD-L1 nanobody could both overcome this limitation and reduce the risk of side effects as the nanobody is enriched in the tumor compared to the periphery.
Legal entity responsible for the study
Ludwig Cancer Research, Brussels Branch - De Duve Institute.
Funding
F.N.R.S. (Fonds National pour la Recherche Scientifique).
Disclosure
B.J. van den Eynde: Advisory/Consultancy: iTEOS therapeutics. All other authors have declared no conflicts of interest.
26P - Cellulose beads prepared in deep eutectic solvent function as carrier and cytoprotective encapsulation matrix for CAR-T cells in T-cell therapy against glioblastoma cells
- Sauli Vuoti (Jyvaskyla, Finland)
- Sauli Vuoti (Jyvaskyla, Finland)
- Minna Saari (Kauhava, Finland)
- Kumar Narasimha (Kauhava, Finland)
- Kai Reinikainen (Kauhava, Finland)
Abstract
Background
Malignant brain tumors, including glioblastoma, represent some of the most difficult to treat of solid tumors. Chimeric antigen receptor (CAR) T cells are a promising immunotherapeutic modality, which utilizes the tumor targeting specificity of any antibody or receptor ligand to redirect the cytolytic potency of T cells. The unique properties of the central nervous system limit T cell entry and risks of immune-based toxicities in highly sensitive environments. This is especially the case for CAR-T cells due to their lability during transfer, manipulation, and storage. Convection Enhanced Delivery (CED) is a technique used to infuse sensitive therapeutic agents directly into the intracranial area continuously under pressure with an improved turnover. Although CED successfully delivers small therapeutic agents, this technique has failed to effectively deliver cells largely due to cell sedimentation or destruction during delivery.
Methods
To overcome the described limitations, we developed a cellulose-based hydrogel matrix with the aid of deep eutectic solvents. The prepared cellulose beads were studied for improving the stability and efficacy of CAR-T cells when utilizing CED. CAR-T cells submitted to CED were counted and the efficiency of delivery was determined. In addition to delivery, the ability of the encapsulated CAR-T cells to migrate and induce cytotoxicity on U87MG-cells was evaluated, and their safety studied using preclinical animal models.
Results
We display that the cellulose beads provided better efficacy for CAR-T cell delivery in CED and protected the cells under serum-free conditions and heat for extended periods of time. The biological activity of the cells was not deteriorated and therapeutic efficacy on glioblastoma cell lines was maintained without signs of increased toxicity when the cells were released from the cellulose bead carriers.
Conclusions
The biodegradable cellulose beads were capable of retaining CAR-T cells in suspension and enhanced cell viability in clinically relevant settings, while maintaining biological activity for therapeutic efficacy towards glioblastoma cell lines.
Legal entity responsible for the study
Chembrain Ltd.
Funding
Chembrain LTD.
Disclosure
S. Vuoti: Full/Part-time employment, The work presented in this abstract was conducted before start of employment: Eli Lilly. M. Saari: Full/Part-time employment: Chembrain Ltd. K. Narasimha: Full/Part-time employment: Chembrain Ltd. K. Reinikainen: Full/Part-time employment: Chembrain Ltd.
27P - Methodology for identification of clinically relevant targets for TCR-immunotherapy in hepatocellular carcinoma
- Panagiota Maravelia (Huddinge, Sweden)
- Panagiota Maravelia (Huddinge, Sweden)
- André Potti (Huddinge, Sweden)
- Daniela Silva Silva (Huddinge, Sweden)
- Takuya Sekine (Huddinge, Sweden)
- Katie Healy (Huddinge, Sweden)
Abstract
Background
Hepatocellular carcinoma (HCC) is a primary type of liver cancer that ranks as the fourth most leading cause of cancer-related deaths world-wide. Treatment options including ablation and chemotherapies are not always efficient to eliminate advanced HCC. Immunotherapies have general low response rates in advanced HCC patients, indicating that new approaches are needed in order to improve the current clinical responses. Our main objective is to identify mutations that can be clinically relevant targets for T cell immunotherapy in HCC patients.
Methods
Here we present data from three advanced HCC patients that underwent liver transplantation. Tumors from the explanted livers were sequenced with the Illumina Trusight Oncology 500 platform. This platform allowed us to focus on clinically relevant tumor mutations and at the same time acquire information on the patient HLA restriction, in order to perform HLA binding prediction analysis. The mutations were ranked according to their specific relevance for HCC, presence of frequent substitutions (hot-spot) and likelihood of HLA binding. The screening of the synthesized peptides and minigenes encoding the top-ranking mutations for their ability to activate T cells is ongoing.
Results
16, 13 and 7 top ranking somatic mutations were identified respectively for the three patients. Among those, we identified ‘hot-spot’ mutations in driver oncogenes such as the CTNNB1 and other highly frequent HCC associated genes including the PIK3CA, CDKN2A and KMT2C. For each frequent HLA allele such as A*01, A*02, A*03, B*07 and C*03 we identified between 4 and 12 peptides with high predicted binding affinity.
Conclusions
Based on these preliminary data from three advanced HCC samples, we identified hot-spot mutations in driver oncogenes and highly frequent HCC associated genes. We also identified potential high affinity binders for frequently expressed HLA class I alleles. These data are increasing the likelihood of identifying T cell receptors that can be used for T cell-based immunotherapy broadly in a high number of cancer patients. The immunological testing of these mutations and the identification of specific T cell receptors is still ongoing.
Legal entity responsible for the study
Karolinska Institute.
Funding
Center for Innovative Medicine and Sjöberg Foundation.
Disclosure
All authors have declared no conflicts of interest.
28P - Helping the killers: Innovative cancer immunotherapy harnessing quasi-universal tumour antigen-specific CD4 T cells
- Margaux Saillard (Lausanne, Switzerland)
- Margaux Saillard (Lausanne, Switzerland)
- Amélie Cachot (Lausanne, Switzerland)
- Alexander Rockinger (Lausanne, Switzerland)
- Philippe Guillaume (Lausanne, Switzerland)
- Julien Schmidt (Lausanne, Switzerland)
Abstract
Background
While cancer immunotherapy has mainly focused on exploiting CD8 T cells given their role in the direct elimination of tumor cells, increasing evidence highlights the crucial roles played by CD4 T cells in anti-tumor immunity. However, their very low frequency, the lack of robust algorithms to predict peptide binding to MHC class II molecules and the high polymorphism of MHC class II molecules render the study and use of circulating tumor antigen-specific CD4 T cells challenging. In this regard, the HLA-DRB3*02:02 gene encoding an HLA allele that is expressed by half of the Caucasian population, offers a way to identify CD4 T cell-defined tumor antigens with broad cancer patient coverage.
Methods
Here, we aim to identify, isolate and functionally characterize “quasi-universal” human tumor antigen-specific HLA-DRB3*02:02-restricted CD4 T cells in cancer patients. Using an algorithm we recently developed in house, tumor-associated antigenic peptides binding to this allele are identified.
Results
We have generated a large collection of HLA-DRB3*02:02-restricted CD4 T cell clones of different tumor-antigen specificities. We will perform in vitro co-cultures of CD4 T cell clones with tumor cells to measure cytokine secretion, their tumor cell killing and their phenotypic profile (PD-1, TIM3, TIGIT, 4-1BB, CD40L, LAG3, VISTA, OX40). We will sequence and clone the TCR of the most promising candidates for adoptive cell transfer therapy. Lastly, we will directly evaluate the presence of these cells ex-vivo and longitudinally monitor them in patients.
Conclusions
Together, these results should contribute valuable targets for coordinated CD4 and CD8 T cell-based immunotherapy of cancer.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.