Cells In Tumor-infiltrating Lymphocytes Research Articles

IMMU-03. EXPLORING CANCER-SPECIFIC T CELLS AND ANTIGENS IN GLIOBLASTOMA BASED ON SINGLE-CELL SEQUENCING OF CD8+ TILS

Abstract BACKGROUND The effectiveness of cancer immunotherapy against glioblastoma (GBM) remains limited. This study aims to identify cancer-specific antigens to develop antigen-based cancer immunotherapies for GBM. We investigated candidate tumor antigen-specific T cells in GBM by single-cell RNA sequencing (scRNA-seq) and single-cell TCR sequencing (scTCR-seq), and we explored candidate antigens through genetic analysis of tumor tissues. METHODS Flow cytometry analysis was conducted on fresh tumor digest samples to evaluate tumor-infiltrating lymphocytes (TILs) of GBM. Single-cell RNA and TCR sequencing were performed on CD8+ T cells in TILs. Both data generated by Cell Ranger software were loaded into Seurat at R studio. The dimensional reduction for clustering was performed with uniform manifold approximation and projection (UMAP). Additionally, we performed bulk RNA sequencing (RNA-seq) and whole exome sequencing (WES) on tumor tissues. RESULTS Two out of 20 patients (10%) exhibited abundant TILs in GBM. From these two patients, approximately 20,000 CD8+ T cells in total were analyzed in single-cell analysis. Clustering based on UMAP revealed a predominance of clusters expressing exhaustion markers, with high TCR clonality centered on exhausted T cell (TEX) clusters, like our previous date of lung cancer TILs recognizing tumor antigens. Moreover, within the TEX clusters, the expression of CXCL13, often reported as an antigen-specific marker in recent years, was significantly higher in our data compared to two publicly available datasets. Subsequently, based on RNA-seq and WES, 61 candidate neoantigens were estimated using machine-learning prediction algorithms from NEC Corporation. Furthermore, 5 overexpressed cancer/testis antigens, and 3 bacterial species-derived microbial peptides using Kraken2 were selected as antigen candidates. CONCLUSIONS We identified prospective tumor antigen-specific T cell subsets with high CXCL13 expression from two GBM patients. We plan to identify cancer-specific T cells and antigens from these candidates by T cell activation assay.

Overcoming immunotherapy resistance and inducing abscopal effects with boron neutron immunotherapy (B-NIT).

Immune checkpoint inhibitors (ICIs) are effective against many advanced malignancies. However, many patients are nonresponders to immunotherapy, and overcoming this resistance to treatment is important. Boron neutron capture therapy (BNCT) is a local chemoradiation therapy with the combination of boron drugs that accumulate selectively in cancer and the neutron irradiation of the cancer site. Here, we report the first boron neutron immunotherapy (B-NIT), combining BNCT and ICI immunotherapy, which was performed on a radioresistant and immunotherapy-resistant advanced-stage B16F10 melanoma mouse model. The BNCT group showed localized tumor suppression, but the anti-PD-1 antibody immunotherapy group did not show tumor suppression. Only the B-NIT group showed strong tumor growth inhibition at both BNCT-treated and shielded distant sites. Intratumoral CD8+ T-cell infiltration and serum high mobility group box1 (HMGB1) levels were higher in the B-NIT group. Analysis of CD8+ T cells in tumor-infiltrating lymphocytes (TILs) showed that CD62L- CD44+ effector memory T cells and CD69+ early-activated T cells were predominantly increased in the B-NIT group. Administration of CD8-depleting mAb to the B-NIT group completely suppressed the augmented therapeutic effects. This indicated that B-NIT has a potent immune-induced abscopal effect, directly destroying tumors with BNCT, inducing antigen-spreading effects, and protecting normal tissue. B-NIT, immunotherapy combined with BNCT, is the first treatment to overcome immunotherapy resistance in malignant melanoma. In the future, as its therapeutic efficacy is demonstrated not only in melanoma but also in other immunotherapy-resistant malignancies, B-NIT can become a new treatment candidate for advanced-stage cancers.

Lifileucel, an Autologous Tumor-Infiltrating Lymphocyte Monotherapy, in Patients with Advanced Non-Small Cell Lung Cancer Resistant to Immune Checkpoint Inhibitors.

In this phase 2 multicenter study, we evaluated the efficacy and safety of lifileucel (LN-145), an autologous tumor-infiltrating lymphocyte cell therapy, in patients with metastatic non-small cell lung cancer (mNSCLC) who had received prior immunotherapy and progressed on their most recent therapy. The median number of prior systemic therapies was 2 (range, 1-6). Lifileucel was successfully manufactured using tumor tissue from different anatomic sites, predominantly lung. The objective response rate was 21.4% (6/28). Responses occurred in tumors with profiles typically resistant to immunotherapy, such as PD-L1-negative, low tumor mutational burden, and STK11 mutation. Two responses were ongoing at the time of data cutoff, including one complete metabolic response in a PD-L1-negative tumor. Adverse events were generally as expected and manageable. Two patients died of treatment-emergent adverse events: cardiac failure and multiple organ failure. Lifileucel is a potential treatment option for patients with mNSCLC refractory to prior therapy. Significance: Autologous tumor-infiltrating lymphocyte therapy lifileucel was administered to 28 patients with heavily pretreated metastatic non-small cell lung cancer (mNSCLC). Responses were observed in patients with driver mutations, and various tumor mutational burdens and PD-L1 expression, potentially addressing an unmet medical need in patients with mNSCLC refractory to prior therapy. See related commentary by Lotze et al., p. 1366.

Dehydroepiandrosterone attenuated the immune escape of oral squamous cell carcinoma through NF-κB p65/miR-15b-5p/B7-H4 axis

ObjectivesWe aimed to explore the effects and mechanisms of action of dehydroepiandrosterone (DHEA) on immune evasion of oral squamous cell carcinoma (OSCC) to provide evidence for enhancing the effect of immunotherapy. Materials and MethodsA xenograft mouse model and immunohistochemistry were used to reveal the patterns of tumor-infiltrating lymphocytes (TILs). The CAL27 and SCC VII cell lines were used for the in vitro study. Western blotting, qPCR, immunofluorescence, and flow cytometry were used to evaluate the expression of B7-H4. Recombinant mouse B7-H4 protein (rmB7-H4) and PG490, an inhibitor of NF-κB p65 were used for the “rescue study.” Gain- and loss-of-function, luciferase reporter, and chromatin immunoprecipitation assays were performed to verify this mechanism. ResultsDHEA inhibited tumor growth in an OSCC xenograft mouse model, increased CD8 + cells, and decreased FOXP3 + cells in TILs. DHEA reduced the expression of B7-H4 in CAL27 and SCC VII cells RmB7-H4 reverses the effect of DHEA on tumor growth and TIL patterns. DHEA increased the expression of miR-15b-5p and activated its transcriptional factor NF-κB p65. Further experiments demonstrated that miR-15b-5p inhibited B7-H4 expression by binding to its 3′-UTR regions, and NF-κB p65 activated miR-15b transcription. PG490 reversed the effects of DHEA on tumor growth, antitumor immunity in the OSCC xenograft model, and the expression/phosphorylation of NF-κB p65, miR-15b-5p, and B7-H4. ConclusionsThis study indicates that DHEA attenuates the immune escape of OSCC cells by inhibiting B7-H4 expression, providing new insights for cancer immunotherapy.

IOV-3001, a modified interleukin-2 fusion protein, for potential use in tumor-infiltrating lymphocyte cell therapy regimens.

2552 Background: Tumor-infiltrating lymphocyte (TIL) cell therapy has shown promising efficacy in patients with solid tumor malignancies. Interleukin-2 (IL-2) administration after TIL infusion supports persistence and survival of infused TIL. Aldesleukin is a synthetic IL-2 with a short half-life administered every 8–12 hours, to support the expansion and persistence of the TIL in vivo. IOV-3001 is a modified dimeric IL-2 fused to palivizumab that has a longer half-life and potentially better safety profile, compared with aldesleukin. Here, we describe the preclinical activity, pharmacokinetics (PK), pharmacodynamics (PD), and in vivo safety profile of IOV-3001. Methods: Binding of IOV-3001 and aldesleukin to the IL-2 receptor (IL-2R), IL-2R-mediated activation via STAT5 phosphorylation, and T cell proliferation were assessed. Pharmacological activities of IOV-3001 and aldesleukin were evaluated in B16-F10 mice infused with pmel-1 T cells. Safety after a single dose of IOV-3001 (0.01–9.0 mg/kg) was assessed in cynomolgus monkeys across 3 independent studies. PK and PD parameters, clinical pathology, hematology, and histopathology were assessed. Results: Both IOV-3001 and aldesleukin induced comparable STAT5 phosphorylation and proliferation of T-cell subsets. Mice infused with pmel-1 T cells and subsequently treated with IOV-3001 or aldesleukin showed similar reductions in tumor burden. The half-life of IOV-3001 in cynomolgus monkeys ranged from 5–8 hours. IOV-3001 was well tolerated in monkeys across the dose range studied except for 1 animal administered IOV-3001 at the highest tested dose level, with recovery by Day 29. Inflammatory cytokines (IL-12 p40, IL-6, MCP-1) increased from 4 hours to ≤3 days after dosing and returned to baseline by Day 29. Fibrinogen, bilirubin, and triglycerides increased on Day 3 and returned to baseline by Day 29. No signs of capillary leak were observed. Increased numbers of hematopoietic cells were found in the bone marrow, spleen, and lymph nodes 3 days post dosing. During the 4-week recovery, these changes diminished or resolved, while bone marrow showed differential dose-dependent effects. IL-2–induced proinflammatory PD effects were observed, including >10-fold peak CD8+ T cell expansion in peripheral blood mononuclear cells at Day 5 versus preacclimation in most cynomolgus monkeys treated with IOV-3001. Conclusions: IOV-3001 exhibited a similar mechanism of action (MoA) to that of aldesleukin in vitro and has a longer half-life in vivo. PD effects were consistent with the MoA of IL-2. IOV-3001 showed a favorable preclinical safety profile. These results suggest a potentially improved safety profile for IOV-3001 with less frequent dosing compared with aldesleukin. These features of IOV-3001 strongly advocate for its development in TIL cell therapy regimens.

A phase 1/2 study to investigate the safety and efficacy of OBX-115 engineered tumor-infiltrating lymphocyte (TIL) cell therapy in patients (pts) with advanced solid tumors.

TPS9599 Background: Immune checkpoint inhibitors (ICI) have improved outcomes for pts with solid tumor malignancies; however, most pts relapse and treatment options are limited. Unengineered TIL cell therapy has shown promising efficacy in pts with ICI-resistant melanoma (1,2) and non-small cell lung cancer ([NSCLC] 3,4), but requires co-administration of systemic high-dose IL2, which is associated with safety risks and limits pt eligibility. OBX-115 TIL are engineered to express membrane-bound IL15 (mbIL15) under dose-dependent regulation using acetazolamide (ACZ), an FDA-approved small-molecule diuretic, avoiding the need for high-dose IL2. A first-in-human single-institution study (NCT05470283) evaluating the safety of OBX-115 in metastatic melanoma is ongoing. The current study (NCT06060613) is enrolling pts with solid tumors at multiple US sites using centralized manufacturing. Methods: This phase 1/2, single-arm, open-label, nonrandomized, multicenter study will assess the safety, tolerability, and efficacy of the OBX-115 engineered autologous TIL cell therapy regimen in pts with histologically confirmed unresectable Stage IIIC, IIID, or Stage IV metastatic melanoma (excluding uveal) with documented radiographic progression after systemic therapy containing an anti–PD‐1/PD-L1 agent (if adjuvant, progression during or within 12 wks after the last dose) and received a BRAF inhibitor ± MEK inhibitor if BRAF V600 mutation-positive OR metastatic NSCLC previously treated with an approved systemic therapy for metastatic disease (including an ICI-based regimen and/or targeted therapy where applicable) and progressed, no longer deriving benefit, or unable to continue due to treatment intolerance. Pts must have ECOG PS of 0 or 1 and life expectancy >~6 months. Pts must have ≥1 lesion suitable for OBX-115 manufacturing (≥1.5 cm) and ≥1 RECIST v1.1-measurable lesion remaining after tumor tissue procurement. Primary objectives of Phase 1 are to characterize safety and tolerability and identify a recommended Phase 2 dose of OBX-115 + ACZ; Phase 2 will evaluate efficacy of the regimen (ORR using RECIST v1.1 per investigator). Cryopreserved OBX-115 is generated from the pt’s own tumor tissue procured by surgical excision or core needle biopsy, and is infused after standard- (5 days) or low-dose (4 days) lymphodepletion (cyclophosphamide and fludarabine), based on clinical status. ACZ is administered at cohort-defined doses once daily for up to 10 days starting day of OBX-115 infusion, with optional ACZ redosing at Wk 6–8 for up to 10 days in pts with suboptimal radiographic response. No systemic high-dose IL2 is administered. Two sites are open and recruiting, with additional sites being activated. 1. Rohaan NEJM 2022. 2. Chesney JITC 2022. 3. Creelan Nat Med 2021; Schoenfeld SITC 2021. Clinical trial information: NCT06060613 .

OBX-115, an interleukin 2 (IL2)-sparing engineered tumor-infiltrating lymphocyte (TIL) cell therapy, in patients (pts) with immune checkpoint inhibitor (ICI)-resistant unresectable or metastatic melanoma.

9515 Background: Investigational unengineered TIL cell therapy has shown promising activity in ICI-resistant metastatic melanoma but requires systemic high-dose IL2, which has well-described high-grade toxicity frequently requiring specialized management and limiting pt eligibility. OBX-115 autologous engineered TIL cell therapy does not require co-administration of IL2 due to its regulatable expression of membrane-bound IL15 (mbIL15) using the FDA-approved small-molecule drug acetazolamide (ACZ) to provide cytokine support for TIL expansion and persistence. Methods: This Phase 1 study (NCT05470283) assesses the OBX-115 regimen in pts with ICI-resistant unresectable/metastatic melanoma. OBX-115 is manufactured from the pt’s tumor tissue (surgical excision or core needle biopsy [CNB]). After lymphodepletion (cyclophosphamide, fludarabine), pts receive OBX-115 followed by ACZ once daily for up to 7 days; ACZ redosing (up to 7 days) is permitted at Wk 6 for non-responders. No systemic IL2 is administered. Peripheral blood and tumor tissue is collected for longitudinal immune profiling. Results: As of 02 Jan 2024, 9 pts (median age, 50 y) with ICI-resistant metastatic melanoma were infused with OBX-115 (median study follow up, 17 wks; range, 2–58 wks). Median lines of prior therapy was 3 (range, 1–6). OBX-115 was successfully manufactured for all pts, including from CNB tumor tissue (n = 5). The infusion product had a high proportion of CD8+ cells (≥96%) and stem-like cells (CD8+CD39-CD69-; median 76%) with very low PD-1 expression in the CD8+ population ( < 1%). Post-infusion safety included no DLTs, 3 Gr 3 nonhematologic TEAEs in 2 pts (abdominal pain, ALT elevation, syncope), and no Gr 4 nonhematologic TEAEs. ACZ was redosed and well-tolerated in 4 of 5 eligible pts. Among patients with minimum 12-wk follow-up (n = 6), ORR per RECIST v1.1 was 50% (2 CR, 1 PR, 3 SD); all responses occurred between Wk 6–18 and were ongoing, with longest response sustained > 12 mo. One pt developed new metastatic disease (liver) and progressed at Wk 24, despite continued target lesion reduction; no pt developed brain metastasis. Post-infusion ctDNA was not detectable in any of the responders at Day 14 or 42. Though OBX-115 had minimal NK cells ( < 1%), post-infusion peripheral blood and tumor biopsies showed NK cell expansion, consistent with trans-presentation of mbIL15 to circulating NK cells. Updated efficacy data on all infused pts will be presented. Conclusions: OBX-115regulatableengineeredTIL cell therapy was well-tolerated and produced consistently deepening and durable responses, indicating that OBX-115 may mediate CRs and durable clinical benefit in ICI-resistant metastatic melanoma without high-dose IL2. OBX-115 investigation continues in this and an ongoing Phase 1/2 multicenter study (NCT06060613). Clinical trial information: NCT05470283 .

Dynamics of circulating cytokines and chemokines during and after tumor-infiltrating lymphocyte cell therapy with lifileucel in advanced melanoma patients.

9594 Background: Lifileucel, a one-time autologous tumor-infiltrating lymphocyte (TIL) cell therapy, has demonstrated potentially clinically meaningful activity and durable responses in patients with advanced (unresectable or metastatic) melanoma. The regimen includes nonmyeloablative lymphodepletion (NMA-LD) prior to lifileucel infusion, and a short course of interleukin-2 (IL-2) post infusion. The safety profile of the regimen is consistent with the underlying disease and the known safety profiles of NMA-LD and IL-2. Cytokine release syndrome (CRS) is an acute and severe adverse event commonly associated with chimeric antigen receptor T-cell therapy. Here, we report circulating cytokine levels during and after the lifileucel treatment to monitor immune activation, and the dynamics of cytokines and chemokines to explore mechanism of action and potential predictive clinical biomarkers. Methods: The full analysis set of C-144-01 (NCT02360579) includes 153 patients with unresectable or metastatic melanoma who have progressed on checkpoint inhibitors and, if applicable, BRAF/MEK inhibitors. After tumor resection, patients received NMA-LD (cyclophosphamide on Days −7 to −6 and fludarabine on Days −5 to −1) followed by a single lifileucel infusion (Day 0) and up to 6 doses of IL-2 (Days 0-4). Peripheral blood samples were collected at baseline (pre-NMA-LD and pre-lifileucel infusion) and post-lifileucel infusion on Days 1, 4, 14, 42, and 84. Serum cytokine and chemokine levels were measured with BioPlex and included a multiplex panel for IL-6, IL-7, IL-9, IL-10, IL-12, CCL2, CXCL10, IFN-γ, and TNF-α. Plasma samples also were tested for IL-6, IL-15, and IL-7 levels by ELISA. Results: IL-15 levels following NMA-LD peaked at Day 1 and returned to baseline by Day 42. This is consistent with prior reports that NMA-LD increases circulating IL-15 levels, which may promote TIL expansion in the absence of competing endogenous lymphocytes. Similarly, IL-7 and CCL2 also peaked at Day 1. IL-6 did not increase during or after the lifileucel regimen, consistent with absence of severe systemic inflammation including higher grade CRS after lifileucel treatment. There was no difference in cytokine and chemokine levels between responders and nonresponders in the full analysis set. Conclusions: These data support the hypothesized mechanism of action of NMA-LD in the lifileucel regimen. Cytokine levels measured during treatment are consistent with lack of severe systemic inflammation observed in patients treated with lifileucel. Cytokine and chemokine dynamics did not predict for response to lifileucel. Clinical trial information: NCT02360579 .

Efficacy and safety of lifileucel, an autologous tumor-infiltrating lymphocyte cell therapy, and pembrolizumab in patients with immune checkpoint inhibitor-naive unresectable or metastatic melanoma: Updated results from IOV-COM-202 cohort 1A.

9505 Background: Immune checkpoint inhibitors (ICI) are front-line standard-of-care treatment (tx) for advanced (unresectable or metastatic) melanoma. Despite recent advances in front-line tx, a majority of patients (pts) do not achieve long-term benefit. Lifileucel, a one-time autologous tumor-infiltrating lymphocyte (TIL) cell therapy, potentially induces durable responses in pts with advanced melanoma previously treated with ICI. This study evaluates lifileucel combined with anti-PD-1 therapy in front-line advanced melanoma. Methods: IOV-COM-202 (NCT03645928) Cohort 1A assesses the efficacy and safety of lifileucel and pembrolizumab (pembro) in pts with ICI-naive unresectable or metastatic melanoma. Pts may have received BRAF/MEK inhibitor tx if BRAF mutation-positive. Eligible pts must have ≥1 resectable lesion (≥1.5 cm diameter) for 22-day cryopreserved lifileucel manufacturing, and ≥1 measurable lesion for response assessment per RECIST v1.1. The tx regimen consists of pembro, nonmyeloablative lymphodepletion (cyclophosphamide and fludarabine), a single lifileucel infusion (1 × 109 – 150 × 109 cells), ≤6 doses of IL-2 (600,000 IU/kg IV), and continued pembro until disease progression, or unacceptable toxicity for ≤24 months. The endpoints are investigator-assessed objective response rate (ORR) and incidence of grade ≥3 treatment-emergent adverse events (TEAE). Results: As of 22-Dec-2023, 22 pts with a median (range) age of 48.5 (18–68) years received lifileucel and pembro. At baseline, the median (range) target lesion sum of diameters was 54.5 (14–355) mm; 7 (31.8%) pts had liver lesions. Metastatic staging at study entry was as follows: 4 (18.2%) had M1a, 2 (9.1%) had M1b, 10 (45.5%) had M1c, and 2 (9.1%) had M1d. Eight (36.4%) pts had V600 BRAF mutations; 3 (13.6%) pts had prior BRAF/MEK inhibitor tx. Confirmed ORR was 63.6% (14/22), including 22.7% (5/22) CR and 40.9% (9/22) PR; 6 pts (27.3%) had SD. Median time to initial response was 2.5 months. All response evaluable pts demonstrated regression of target lesions. At a median follow-up of 17.2 months, median duration of response was not reached. Responses deepened over time; 10/14 (71.4%) pts had ongoing response and 8/14 (36.4%) pts had response ≥12 months. TEAEs were consistent with the underlying disease and known safety profiles of pembro, nonmyeloablative lymphodepletion, and IL-2. Most common grade ≥3 TEAEs were thrombocytopenia (68.2%), neutropenia (50.0%), and anemia (45.5%). Conclusions: These results demonstrate encouraging efficacy and durability for the combination of lifileucel and pembro and support its further evaluation in pts with untreated advanced melanoma in the phase 3 study TILVANCE-301 (NCT05727904). Clinical trial information: NCT03645928 .

A first-in-human study of CRISPR/Cas9-engineered tumor infiltrating lymphocytes (TILs) product GT316 as monotherapy in advanced solid tumors.

2549 Background: A next-generation TIL product GT316 was engineered with CRISPR/Cas9 to genetically disrupt two key immunoregulatory targets identified from a genome-wide CRISPR screening platform and demonstrated significantly enhanced anti-tumor efficacy and persistence in pre-clinical animal studies with ameliorated TIL exhaustion profile. A first-in-human trial was initiated to evaluate the preliminary safety and efficacy of GT316 in advanced solid tumors. Methods: The first-in-class study is to enroll patients (pts) with advanced treatment-refractory solid tumors, especially gynecological tumors. Once the optimal biological dose (OBD) is identified, a monotherapy expansion phase will be initiated for pts with various solid tumors. Enrolled pts were preconditioned with a nonmyeloablative (NMA) lymphodepletion regimen and treated by infusion of the GMP-grade G316 product followed by IL-2 administration. Results: As of January 22, 2024, the dose escalation study enrolled 4 pts, all of whom were female with a median age of 58 years with 1 to 9 prior lines of systemic treatment. The median number of infused TIL cells was 1.0E+10. All pts experienced TRAEs with the majority being grade 1 or 2. Grade 3/4 TRAEs included lymphocyte count decreased, white blood cell count decreased, monocyte count decreased and neutrophil count decreased, which were related to the NMA regimen. No dose-limiting toxicities (DLTs) or TIL-related grade≥3 TRAEs were observed. Median time on study was 33.4 wks (8–35 wks). One pt with treatment-refractory cervical cancer experienced a confirmed complete response (CR) after 4 wks and the duration of response is 32 wks by now (RECIST 1.1). One ovarian cancer pt with 9 lines of previous systemic therapies experienced a confirmed partial response (PR) after 4 wks and the duration of response is 22 wks by now (RECIST 1.1). Response data will be continuously collected. The other two ovarian cancer pts experienced stable disease (SD) and progressive disease (PD), respectively. Despite varying doses of TILs (3.2E+09 to 1.90E+10) and IL-2 (up to 3.0E+05 IU/kg), all pts receiving GT316 showed robust TIL expansion post-infusion, which is positively correlated with administrated IL-2 doses. Enhanced IFN-γ secretion could be detected in the serum of the CR and PR pts compared to the SD and PD pts, indicating potential tumor antigen-specific response. Conclusions: The first-in-human study of GT316, a CRISPR/Cas9-dual KO anti-exhaustion TIL product, demonstrates good tolerability with encouraging preliminary anti-tumor efficacy as a monotherapy in pts with advanced solid cancers. The infusion of GT316 was associated with robust TIL expansion and IFN-γ secretion. Updated data with additional follow-up will be continuously collected, and OBD will be determined based on the overall data of safety and preliminary efficiency. Clinical trial information: NCT06145802 .

3D tumor spheroids promote activation, expansion, and anti-tumor effects of tumor-infiltrating lymphocytes in vitro

The adoptive immunotherapy mediated by tumor-infiltrating lymphocytes (TILs) has shown definite efficacy against various solid tumors. However, the inefficiency of the conventional method based on in vitro expansion of TILs fails to achieve the cell count and high tumor-killing activity required for therapeutic purposes. This study investigated the effect of 3D tumor spheroids on the activation and expansion of TILs in vitro, aiming to provide a novel approach for the expansion of TILs. We procured TILs and primary tumor cells from surgical samples of lung cancer patients and then compared the impacts of lung cancer cell line NCI-H1975 and primary lung cancer cells cultured under 2D and 3D conditions on the activation, expansion, and anti-tumor activity of TILs. Furthermore, we added the programmed cell death protein 1 (PD-1) antibody into the co-culture of primary tumor cells and TILs within a 3D environment to assess the effects of the antibody on TILs. The results showed that compared with 2D cultured tumor cells, the 3D cultured H1975 cells significantly enhanced the expansion of TILs, increasing the proportion of CD3+/CD8+ cells in TILs to 61.6%. The 3D primary tumor model also enhanced the proportion of CD3+/CD8+ cells in TILs (45.5%, 54.4%), induced apoptosis of tumor epithelial cells and decreased the overall tumor cells survival rate (16.7%) after co-culture. PD-1 antibodies further improved the in vitro expansion capacity of TILs mediated by 3D tumor spheroids, resulting in the proportions of 50.9% and 57.0% for CD3+/CD8+ cells and enhancing the antitumor activity significantly (reducing the overall tumor survival rate to 9.36%). In summary, the use of 3D tumor spheroids significantly promoted the expansion and improved the anti-tumor effect of TILs, and the use of the PD-1 antibody further promoted the expansion and tumor-killing effect of TILs.

Abstract CT285: Trial in progress: A phase 1/2 study to investigate the safety and efficacy of OBX-115 engineered tumor-infiltrating lymphocyte (TIL) cell therapy in patients (pts) with immune checkpoint inhibitor (ICI)-resistant advanced or metastatic melanoma

Abstract Introduction ICI have improved outcomes for pts with melanoma; however, most pts (~60%) do not achieve long-term survival. Unengineered bulk TIL cell therapy has an objective response rate (ORR) of 31-49% in pts with unresectable or metastatic melanoma (Rohaan NEJM 2022, Chesney JITC 2022), but requires co-administration of systemic high-dose IL2, which is associated with safety risks and limits pt eligibility. OBX-115 TIL are engineered to express regulatable membrane-bound IL15 (mbIL15) under dose-dependent regulation using acetazolamide (ACZ), an FDA-approved small-molecule diuretic, avoiding the need for high-dose IL2. A first-in-human single-institution study (NCT05470283) evaluating the safety of OBX-115 in metastatic melanoma is currently enrolling. The current study (NCT06060613) is enrolling at multiple US sites using centralized manufacturing. Methods This phase 1/2, single-arm, open-label, nonrandomized, multicenter study will assess the safety, tolerability, and efficacy of the OBX-115 engineered autologous TIL cell therapy regimen in pts with unresectable or metastatic melanoma resistant to ICI (Table). Primary objectives of Phase 1 are to characterize safety and tolerability and identify a recommended Phase 2 dose of the OBX-115 regimen; Phase 2 will evaluate efficacy (ORR using RECIST v1.1). Cryopreserved OBX-115 is generated from the pt’s own tumor tissue procured by surgical excision or core biopsy, and is infused after standard- or low-dose (based on clinical eligibility) lymphodepletion (cyclophosphamide and fludarabine). ACZ is administered at cohort-defined doses once daily for up to 10 days, with ACZ redosing at Week 6-8 for 10 days if the initial observed tumor response is less than partial response. No systemic high-dose IL2 is administered. Two sites are open and recruiting pts. TABLE 1. NAND Key Eligibility Criteria Key Inclusion Criteria Key Exclusion Criteria Age ≥18 years Uveal melanoma Histologically confirmed diagnosis of unresectable Stage IIIC, IIID, or Stage IV metastatic melanoma Brain metastasis or leptomeningeal disease Documented radiographic disease progression after systemic therapy containing a PD-1- or PD-L1-blocking antibody (if adjuvant setting, progression during or within 12 weeks after the last dose) Active autoimmune disease, including active uveitis or any other medical illness that would pose increased risks for study participation Received a BRAF inhibitor ± MEK inhibitor if BRAF V600 mutation-positive Prior allogeneic organ transplant, allogeneic cell therapy, or genetically engineered cell therapy (not including autologous stem cell or unengineered TIL cell therapy) ≥1 lesion suitable for OBX-115 generation with expected minimum of 1.5-cm diameter; minimally invasive tumor tissue procurement (core biopsy) may be considered on a case-by-case basis after discussion with the Medical Monitor Systemic steroid therapy >10 mg/day of prednisone or equivalent ≥1 RECIST 1.1-measurable lesion remaining after tumor tissue procurement ECOG performance status 0 or 1 Estimated life expectancy >6 months Citation Format: Sajeve S. Thomas, Jason A. Chesney, Omid Hamid, Gino K. In, Alexander N. Shoushtari, Yazan Samhouri, Parameswaran Hari, Giridharan Ramsingh, Prakash Prabhakar, Lauren Mclaughlin, Allison Betof Warner. Trial in progress: A phase 1/2 study to investigate the safety and efficacy of OBX-115 engineered tumor-infiltrating lymphocyte (TIL) cell therapy in patients (pts) with immune checkpoint inhibitor (ICI)-resistant advanced or metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT285.

Abstract CT286: TILVANCE-301, a phase 3 study of lifileucel tumor-infiltrating lymphocyte (TIL) cell therapy in combination with pembrolizumab vs pembrolizumab alone in treatment-naive unresectable or metastatic melanoma

Abstract Introduction: Novel early-line therapies for advanced (unresectable or metastatic) melanoma are needed to improve the rate of deep and durable responses and increase the proportion of patients with long-term benefit. TILVANCE-301 will evaluate the efficacy and safety of lifileucel autologous TIL cell therapy plus pembrolizumab in patients with untreated advanced melanoma. Methods: TILVANCE-301 (NCT05727904) is a phase 3, multicenter, randomized, open-label, parallel group study that will randomize ~670 patients (1:1; Day 0) to Arm A: lifileucel plus pembrolizumab (Day 3: tumor tissue resection for TIL manufacturing; Day 5: pembrolizumab 200 mg; Day 26: pembrolizumab 400 mg; Day 28-29: cyclophosphamide 60 mg/kg; Day 28-32: fludarabine 25 mg/m2; Day 33: lifileucel; Day 34-37: ≤6 doses of high-dose IL-2; Week 10: pembrolizumab 400 mg Q6W) or Arm B: pembrolizumab alone (same pembrolizumab dosing as Arm A). Patients in Arm B with confirmed progressive disease verified by blinded independent review committee (BIRC) have the option to receive lifileucel monotherapy as immediate next treatment and may continue pembrolizumab until start of nonmyeloablative lymphodepletion. Eligible adults have histologically confirmed advanced melanoma, Eastern Cooperative Oncology Group performance status of 0-1, estimated life expectancy >6 months, ≥1 resectable lesion to generate lifileucel, and ≥1 remaining measurable lesion. Prior neoadjuvant or adjuvant treatment including immune checkpoint inhibitors may be allowed. Prior therapy for metastatic disease, symptomatic untreated brain metastases, organ allograft or prior cell therapy, uveal/ocular melanoma, and chronic systemic steroid therapy are not permitted. The dual primary efficacy endpoints are BIRC-assessed (RECIST v1.1) objective response rate (ORR) and progression-free survival (PFS). Key secondary efficacy endpoint is overall survival. Additional secondary efficacy endpoints include BIRC-assessed complete response (CR) rate, duration of response (DOR), and event-free survival (EFS); investigator-assessed ORR, PFS, CR rate, DOR, EFS, and PFS2; and safety as characterized by severity and seriousness of treatment-emergent adverse events and relationship to study drug. Exploratory endpoints include in vivo T-cell persistence (unique CDR3 sequences in peripheral blood mononuclear cell [PBMC] over time) and correlative biomarkers (eg, lifileucel phenotypic and functional characteristics; lifileucel, tumor, and PBMC gene expression profiles; tumor mutational landscape). The study will enroll globally, with initial sites in Europe, North America, and Australia. Trial registration: NCT05727904 Citation Format: Sajeve Thomas, Young Ki Hong, Yazan Samhouri, James Larkin, David J. Olson, Gino K. In, Victoria Atkinson, Philip Lammers, Andrew J. Furness, Juan Martin-Liberal, Patrick Terheyden, Andrew S. Poklepovic, Ryan H. Nguyen, Idit Peretz, Marcus Butler, Adnan Khattak, Lavinia Spain, E.M. Gaughan, Melissa Wilson, John W. Dubay, Anja Williams, Stephanie Goff, Gary C. Doolittle, Jason Chesney, Friedrich Graf Finckenstein, Jeffrey Chou, Xiao Wu, Giri Sulur, Wen Shi, John Haanen. TILVANCE-301, a phase 3 study of lifileucel tumor-infiltrating lymphocyte (TIL) cell therapy in combination with pembrolizumab vs pembrolizumab alone in treatment-naive unresectable or metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT286.

Abstract CT176: OBX-115 engineered tumor-infiltrating lymphocyte (TIL) cell therapy induced deepening and durable responses without interleukin 2 (IL2) in patients (pts) with immune checkpoint inhibitor (ICI)-resistant unresectable or metastatic melanoma

Abstract Introduction: Treatment options are limited for pts with ICI-resistant metastatic melanoma. Investigational unengineered TIL cell therapy has shown promising activity in this setting, but co-administration of systemic high-dose IL2 limits pt eligibility and is associated with safety risks. OBX-115 is an investigational, autologous TIL cell therapy engineered to express membrane-bound IL15 (mbIL15) under pharmacologic regulation by the FDA-approved small-molecule drug acetazolamide (ACZ) using cytoDRiVE® technology, to induce cytokine-driven TIL expansion and persistence without co-administration of IL2. Methods: This Phase 1 first-in-human study (NCT05470283) is assessing the safety, tolerability, and efficacy of the OBX-115 regimen in pts with unresectable or metastatic melanoma progressing after ICI. Initial pts are enrolled into dose-escalation cohorts (n=3 each; maximum doses: Cohort 1 [C1], 30 × 109 cells + ACZ 125 mg; Cohort 2b [C2b], 100 × 109 cells + ACZ 125 mg). OBX-115 is manufactured using the pt’s tumor tissue (procured by surgical excision or core needle biopsy) and infused after completion of cyclophosphamide and fludarabine lymphodepletion. ACZ is administered orally once daily for up to 7 days, with redosing (Week 6, up to 7 days) permitted for pts without radiographic response at Week 6. No systemic IL2 is administered. The primary objective is to evaluate safety (dose-limiting toxicities [DLTs] and treatment-emergent adverse events [TEAEs]). Results: As of 1 December 2023, 6 pts (age, 28-64 y; C1, n=3; C2b, n=3) with ICI-resistant metastatic melanoma completed the DLT-evaluation period. Median lines of prior therapy was 2.5 (range, 1-5). OBX-115 was successfully manufactured for all 6 pts, including from core needle biopsy tumor tissue (n=5). At 20 weeks median study follow-up (range, 11-51 weeks), no DLTs were observed; 3 pts experienced Gr 3 nonhematologic TEAEs (abdominal pain, ALT elevation, hypokalemia, hyponatremia, syncope) and no Gr 4 nonhematologic TEAEs were reported. Four pts received and tolerated ACZ redosing. ORR per RECIST 1.1 was 50% (2 CR, 1 PR, 3 SD); responses were established between Week 6-18 and ongoing at the time of data cut. All pts had consistent reduction of lesions at each assessment through Week 18. One pt developed new metastatic disease (liver) and progressed at Week 24, despite continued target lesion reduction. Updated data will be presented. Conclusions: OBX-115, a one-time, IL2-free, regulatable, engineered TIL cell therapy, was well-tolerated and induced consistently deepening and durable responses, with the potential to fulfill the unmet need in ICI-resistant advanced melanoma. These early results support continued investigation of the OBX-115 regimen in this and an ongoing Phase 1/2 multicenter study (NCT06060613). Citation Format: Rodabe N. Amaria, Jennifer L. McQuade, Michael A. Davies, Isabella C. Glitza Oliva, Steffy Jose, Erik N. Cressman, Ashlynd L. Clausell, Roland Bassett, Sapna Patel, Adi Diab, Hussein A. Tawbi, Michael K. Wong, Alexandra P. Ikeguchi, Madan Jagasia, Giridharan Ramsingh, Prakash Prabhakar, Raina Duan, Parameswaran Hari. OBX-115 engineered tumor-infiltrating lymphocyte (TIL) cell therapy induced deepening and durable responses without interleukin 2 (IL2) in patients (pts) with immune checkpoint inhibitor (ICI)-resistant unresectable or metastatic melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT176.

Abstract 7608: Exploring the efficacy of atezolizumab plus bevacizumab for advanced hepatocellular carcinoma in relation to tumor-infiltrating lymphocytes

Abstract Background and Aims: Bevacizumab, an anti-angiogenic agent, is reported to enhance antitumor immunity through various mechanisms, including the suppression of regulatory T (Treg) cells. Additionally, a combination therapy involving the anti-PD-L1 monoclonal antibody, atezolizumab, plus bevacizumab (AtezoBev) has emerged as a standard treatment for advanced hepatocellular carcinoma (aHCC). Given that more than half of treated patients do not respond effectively, identifying biomarkers predictive of clinical efficacy has become an urgent matter. However, the investigation into the tumor microenvironment (TME) has been lagging in aHCC compared to other malignancies due to the difficulty in obtaining tumor samples just before the commencement of systemic therapy. Methods: We have established a scheme to analyze the TME by obtaining tumor samples immediately before AtezoBev administration, and explored the relevance to its efficacy, focusing on the tumor-infiltrating lymphocytes (TILs) within those samples. Tumor samples from 94 aHCC patients were collected before AtezoBev administration. TME was assessed in 54 patients via flow cytometry and in 72 patients through RNA sequencing, with certain samples undergoing both analyses. Results: Predominant etiologies in 94 patients were HCV (n=22, 23%), followed by HBV (n=17, 18%), and alcohol abuse (n=16, 17%). The objective response (OR) and disease control rates were 17% and 81%, respectively, with a median progression-free survival (PFS) of 7.6 months. Groups exhibiting high PD-1 positivity of CD8+ T cells (median values as cutoffs) demonstrated superior AtezoBev treatment effects (PFS: 13.1 vs. 4.4 months, p=0.001). In contrast, PD-1 positivity of effector Treg (eTreg) cells in TILs, which reportedly can be one of resistant mechanisms to PD-1 blockade therapy (Togashi Y, et al. Nat Immunol 2020), was not correlated with efficacy. Gene set enrichment analysis highlighted the importance of antigen presentation for OR in groups exhibiting high PD-1 positivity of CD8+ T cells. Additionally, HLA class I expression was elevated in patients achieving an OR. Although previous studies suggest that immunotherapy efficacy could be reduced in non-alcoholic steatohepatitis-related HCC compared with viral-related HCC, no clear association was found between PD-1 positivity of CD8+ T cells or eTreg cells in TILs and etiology. Among the 94 patients, samples from 11 were analyzable at the point of AtezoBev refractoriness, revealing a trend toward reduction in PD-1 positivity of eTreg cells in TILs. Conclusions: Our findings suggest a correlation between the efficacy of AtezoBev for aHCC and the presence of PD-1+CD8+ T cells within the tumor. In contrast, PD-1+ eTreg cells did not induce resistance along with a trend toward reduction after the treatment possibly due to combination with bevacizumab. Citation Format: Hiroaki Kanzaki, Takamasa Ishino, Sadahisa Ogasawara, Sae Yumita, Miyuki Nakagawa, Ryuta Kojima, Keisuke Koroki, Masanori Inoue, Kazufumi Kobayashi, Naoya Kanogawa, Soichiro Kiyono, Masato Nakamura, Takayuki Kondo, Shingo Nakamoto, Tsukasa Takayashiki, Jason Lin, Masahito Kawazu, Mina Komuta, Jun-ichiro Ikeda, Masayuki Ohtsuka, Yosuke Togashi, Naoya Kato. Exploring the efficacy of atezolizumab plus bevacizumab for advanced hepatocellular carcinoma in relation to tumor-infiltrating lymphocytes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7608.

Abstract 25: Multimodal single-cell analysis of lifileucel tumor-infiltrating lymphocyte (TIL) product identifies additional high-resolution potential features

Abstract Introduction: Autologous TIL cell therapies such as lifileucel have demonstrated durable responses in patients (pts) with various solid tumors including melanoma and lung cancer. The TIL drug product (DP) phenotype was previously assessed and extensively characterized based on the bulk population. The current research further characterizes the TIL DP at a single-cell level using high-dimension multimodal sequencing and explores features that have a potential to inform future development of TIL therapies. Methods: Manufactured lifileucel TIL DP from 20 pts (best overall response [BOR]: 6 complete response [CR], 4 partial response, 5 stable disease, 5 progressive disease [PD]) from the registrational melanoma C144-1 trial were analyzed using single-cell RNA and T-cell receptor (TCR) sequencing, resulting in 153K single-cell transcriptomes. To aid with cell-type annotation, 130 surface proteins on TIL DP samples from a subset of 4 pts (BOR: 2 CR, 2 PD) were detected via Cellular Indexing of Transcriptomes and Epitopes by sequencing. Multimodal weighted nearest-neighbor analysis combined with manual cluster annotation (via known marker genes and proteins), cell-type-specific gene signatures, and automated annotation were used to develop a single-cell TIL (scTIL) reference map, resulting in high-resolution subsets of cells. TCR clonotypes from lifileucel TIL DP were compared to those from respective pretreatment tumors previously identified by bulk TCR sequencing. Results: Mapping of the full dataset to the novel scTIL reference revealed a CD8+ TIL-dominant composition of responder TIL DP. TIL from pts with BOR PD exhibited reduced CD8+ effector memory (Tem)-like and resident memory (Trm)-like T cells. Differential expression analysis showed that responder CD8+ TIL had increased expression of TCR signaling genes while responder CD4+ TIL exhibited gene expression consistent with a more cytotoxic-like phenotype. Relative to responders, CD8+ TIL of pts with BOR PD had lower expression of the CD39−CD69− (stem-like) gene signature and higher expression of the CD39+CD69+ (terminal differentiation) gene signature. Pseudotime trajectory analysis found that both CD8+ and CD4+ TIL of pts with BOR PD were more terminally differentiated. Single-cell TCR sequencing revealed that CD8+ T-cell clusters had greater clonal overlap than CD4+ T-cell clusters. Expanded clonotypes in pretreatment tumor tissues were more prevalent in TIL TCR repertoires of responders and were more likely to be expressed by CD8+ (specifically CD8+ Tem- and Trm-like TIL) than CD4+ T cells. Conclusions: Collectively, these results shed additional light on the cellular and molecular characteristics of ex vivo expanded lifileucel TIL DP and signal additional features with a potential to guide future TIL product development. Citation Format: Joe Dean, Joe Yglesias, Hequn Yin, Rongsu Qi. Multimodal single-cell analysis of lifileucel tumor-infiltrating lymphocyte (TIL) product identifies additional high-resolution potential features [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 25.

Potent CTLs can be induced against tumor cells in an environment of lower levels of systemic MFG-E8.

The direction and magnitude of immune responses are critically affected when dead cells are disposed of. Milk fat globule-epidermal growth factor-factor 8 (MFG-E8) promotes the engulfment of apoptotic normal and cancerous cells without inducing inflammation. We have previously reported that a certain proportion of the cancer cells express abundant MFG-E8, and that such expression is associated with the shorter survival of patients with esophageal cancer who had received chemotherapy before surgery. However, the influence of tumor-derived and systemically existing MFG-E8 on antitumor immune responses has not yet been fully investigated. Herein, we showed that CTL-dependent antitumor immune responses were observed in mice with no or decreased levels of systemic MFG-E8, and that such responses were enhanced further with the administration of anti-PD-1 antibody. In mice with decreased levels of systemic MFG-E8, the dominance of regulatory T cells in tumor-infiltrating lymphocytes was inverted to CD8+ T cell dominance. MFG-E8 expression by tumor cells appears to affect antitumor immune responses only when the level of systemic MFG-E8 is lower than the physiological status. We have also demonstrated in the clinical setting that lower levels of plasma MFG-E8, but not MFG-E8 expression in tumor cells, before the treatment was associated with objective responses to anti-PD-1 therapy in patients with non-small cell lung cancer. These results suggest that systemic MFG-E8 plays a critical role during the immunological initiation process of antigen-presenting cells to increase tumor-specific CTLs. Regulation of the systemic level of MFG-E8 might induce efficient antitumor immune responses and enhance the potency of anti-PD-1 therapy.

Carbon Ion Radiotherapy Exerts Anti-Tumor Activity by Inducing cGAS-STING Activation and Immune Response in Prostate Cancer-Bearing Mice

The aim of this study was to assess the influence on immune cell infiltration and T cell effector function to explore the immune response evoked by carbon ion radiotherapy (CiRT) in prostate cancer-bearing mice, and explored the mechanisms underlying CiRT-induced anti-tumor efficacy, involved in cGAS-STING signaling pathway. C57BL/6 and BALB/c nude mouse tumor models were used to evaluate the efficacy of CiRT on tumor growth. Activation of cGAS-STING signaling pathway was performed by immunofluorescence analysis of cytoplasmic double-stranded DNA, western blot analysis of key factors involved in cGAS-STING pathway, and qRT-PCR analysis of the key downstream molecules like CCL5, CXCL10 and IFNβ1. Investigation of alterations of immunophenotypes including the quantification, memory status, exhaustion marker expression, and effector function were assessed by flow cytometry. CiRT showed more powerful tumor growth control of immunocompetent syngeneic C57BL/6 mice than photon radiotherapy did at biological equivalent dose of 5Gy. CiRT induces cytoplasmic DNA and cGAS-STING activation, and is functionally responsible for the observed tumor growth suppression. CiRT exerts anti-tumor effect by triggering immune response, characterized by increased infiltration of CD4+ T cells and macrophages in tumor, enhanced frequencies of CD8+ T cells and CD8+ T effector memory cells in spleen, improved interferon (IFN)-γ production ability of CD8+ tumor-infiltrating lymphocyte cells, and reduced expression of exhausted T cells in tumor and spleen. Our findings indicate that CIRT exerts excellent anti-tumor activity, which may be attributed to the induction of cGAS-STING activation and immune response, manifested by increased immune cell infiltration, improved T cell effector function and enhanced immune memory.

GK-1 effectively reduces angiogenesis and prevents T cell exhaustion in a breast cancer murine experimental model

Breast cancer is the leading malignancy in women worldwide, both in terms of incidence and mortality. Triple-negative breast cancer (TNBC) is the type with the worst clinical outcomes and with fewer therapeutic options than other types of breast cancer. GK-1 is a peptide that in the experimental model of the metastatic 4T1 breast cancer has demonstrated anti-tumor and anti-metastatic properties. Herein, GK-1 (5 mg/kg, i.v.) weekly administrated not only decreases tumor growth and the number of lung macro-metastases but also lung and lymph nodes micro-metastases. Histological analysis reveals that GK-1 reduced 57% of the intra-tumor vascular areas, diminished the leukemoid reaction's progression, and the spleens' weight and length. A significant reduction in VEGF-C, SDF-1, angiopoietin-2, and endothelin-1 angiogenic factors was induced. Moreover, GK-1 prevents T cell exhaustion in the tumor-infiltrating lymphocytes (TILs) decreasing PD-1 expression. It also increased IFN-γ and granzyme-B expression and the cytotoxic activity of CD8+ TILs cells against tumor cells. All these features were found to be associated with a better antitumor response and prognosis. Altogether, these results reinforce the potential of GK-1 to improve the clinical outcome of triple-negative breast cancer immunotherapy. Translation research is ongoing towards its evaluation in humans.

The Peritumoral CD8+/FOXP3+ Cell Ratio Has Prognostic Value in Triple-negative Breast Cancer.

Compelling data has demonstrated the prognostic significance of tumor-infiltrating lymphocytes (TILs) in triple-negative breast cancer (TNBC), a subtype generally associated with a poor clinical outcome but highly heterogeneous in nature. There have been limited studies investigating the importance of subsets of T cells in TILs. Further, the significance of intratumoral versus peritumoral TILs remains controversial. We examined the prognostic value of tumor-associated CD8+ cytotoxic T cells and FOXP3+ regulatory T cells in 35 chemotherapy-naive TNBC cases with a tumor-host interface in the tissue sections. The CD8+ and FOXP3+ cell count was expressed by immunoreactive cells per high-power field in an average of 10 high-power fields. There was a wide range of CD8+ and FOXP3+ T cells within the peritumoral and intratumoral stroma. Both CD8+ and FOXP3+ TILs were significantly higher at the former location as compared with the latter (P<0.0001 and 0.003, respectively). The numbers of CD8+ and FOXP3+ T cells, either within peritumoral or intratumoral stroma, were not significantly associated with distant relapse-free or disease-specific survival. However, the peritumoral CD8+/FOXP3+ ratio of TILs was significantly associated with prolonged relapse-free survival (P=0.04) and disease-specific survival (P=0.02). This association was not observed with the CD8+/FOXP3+ ratio of intratumoral TILs. These observations suggest that the immunologic balance in the tumor microenvironment might determine antitumor immunity. Further, the peritumoral TILs appear to play a more important role in the progression of TNBC when compared with the intratumoral TILs, thus reaffirming the necessity of revisiting the method for the assessment of TILs.