Efficacy Of Immune Checkpoint Inhibitors Research Articles

Immunotherapy-based therapy versus chemotherapy for the neoadjuvant treatment of locally advanced dMMR/MSI-H gastric cancer.

e16121 Background: Growing evidences have suggested that immunotherapy represents a promising treatment for the neoadjuvant treatment of mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) gastric cancer. The study aimed to compare the efficacy of neoadjuvant chemotherapy and immune checkpoint inhibitor (ICI)-based therapy in locally advanced, dMMR/MSI-H gastric cancer. Methods: Patients with MSI-H/dMMR locally advanced gastric cancer who received neoadjuvant chemotherapy, or ICI-based therapy between December 2018 and June 2023 at West China Hospital, Sichuan University were included. Patient data were collected from the prospectively database program of gastric cancer at our Hospital. Demographic and clinicopathologic data of patients were collected, including age, sex, ECOG performance status, primary tumor site, tumor staging, Lauren’s classification, tumor response, tumor regression grade (TRG), R0 resection, disease-free survival (DFS) and overall survival (OS). Results: A total of 21 patients treated with ICIs-based regimens and 18 patients treated with chemotherapy were included. In the ICI-based therapy group, 10 patients (47.6%) received dual PD-1 and CTLA-4 blockade, 1 patient (4.8%) received PD-1 blockade, and 10 patients (47.6%) received PD-1 blockade combined with chemotherapy. The median age of chemotherapy group and ICI-based group were 63 years (range, 36-76 years) and 59 years (range, 34-74 years), respectively. The rates of T4b and limited metastases were significantly higher in the ICI-based therapy group compared to chemotherapy group (T4b: 11.1% vs. 23.8%; limited metastases: 0% vs. 19.0%). 17 patients (94.4%) in the chemotherapy group and 20 patients (95.2%) in the ICI-based therapy group underwent R0 radical gastrectomy. One patient in the chemotherapy group did not undergo surgery due to disease progression. One patient in the ICI-based therapy group refused radical gastrectomy. For patients undergoing surgery, TRG 0-1 rate was obviously lower in patients receiving chemotherapy compared to those treated with ICI-based regimen (0.0% vs. 78.9%). The pCR rates in the chemotherapy group and ICI-based group were 0.0% and 57.9%, respectively. The pCR rates in patients treated with dual PD-1/CTLA-4 blockade and PD-1 blockade with chemotherapy were 66.6% and 50.0% (P = 0.65). Median DFS and OS have not yet been achieved due to the short follow-up time. Conclusions: Improvements in TRG 0-1 rate and pCR rate suggested that ICI-based treatments are favorable in the neoadjuvant setting of locally advanced, dMMR/MSI-H gastric cancer compared to chemotherapy. However, within the overall favorable group, there was no differences between dual PD-1/CTLA-4 blockade and PD-1 blockade with chemotherapy in term of pCR rate. Whether high pCR rates can translate into long-term survival benefits requires longer follow-up time.

Efficacy and safety of immune checkpoint inhibitors in advanced solid tumors with hepatitis B infection.

Efficacy and safety of immune checkpoint inhibitors in advanced solid tumors with hepatitis B infection.

517P Real-world efficacy and safety of immune checkpoint inhibitors (ICI) in gastrointestinal tumors with mismatch repair deficiency or microsatellite instability (dMMR/MSI-H)

517P Real-world efficacy and safety of immune checkpoint inhibitors (ICI) in gastrointestinal tumors with mismatch repair deficiency or microsatellite instability (dMMR/MSI-H)

Penpulimab combined with anlotinib and nab-paclitaxel plus gemcitabine (PAAG) as first-line treatment for metastatic pancreatic cancer: A prospective, multicenter, single-arm, phase 2 study.

4135 Background: Chemotherapy currently serves as the cornerstone for treating metastatic pancreatic cancer (mPC). Nevertheless, the survival of patients with mPC remains poor. Besides, the efficacy of single-agent immune checkpoint inhibitors or antiangiogenesis in the treatment of mPC is not satisfying. Therefore, it is important to explore combination therapy options for patients with mPC. This trial was conducted to evaluate the effectiveness and safety of penpulimab combined with anlotinib and nab-paclitaxel plus gemcitabine (PAAG) for mPC. Methods: This was a prospective, multicenter, single-arm phase II trial. Eligible pts were those who aged over 18 years, histologically or cytologically confirmed PC, have not received treatment before and radiographically showed distant metastases and measurable lesions. Patients received penpulimab (200mg, IV, D1) and Anlotinib (12mg, P.O, QD, D1-14), in addition to nab-paclitaxel (125mg/m2, I.V, D1,8) and gemcitabine (1.0g/m2, I.V, D1,8), administered over a 21-day treatment cycle. The primary endpoint was objective response rate (ORR) and disease control rate (DCR). Secondary end points included Progression-free Survival (PFS), overall survival (OS) and safety. Immune microenvironmental features of baseline were analyzed as exploratory results (NCT05493995). Results: 66 pts were enrolled and received PAAG therapy, and the last follow-up time was December 31, 2023. All pts were eligible for response evaluation. The ORR was recorded at 50% (33/66) (95% CI, 37.4%-62.6%), with 33 pts achieving partial response. The DCR was 95.5% (63/66) (95% CI, 87.3%-99.1%). With median follow-up duration of 12.8 months, median PFS was 8.8 months (95% CI, 8.1–11.3) and median OS was 13.7 months (95% CI, 12.4-not reached). The most common TRAEs were anaemia, leukocytopenia, fatigue and rash. Grade 3 TRAEs were reported in 36.4% pts (24/66). In exploratory analysis, higher T cell recruiting score and lower baseline serum CA72-4 level were detected in PR pts compared with SD/PD pts. Furthermore, the B cell, NK CD56dim cell and Th9 cell scores were up-regulated in PFS-long pts. Conclusions: PAAG regimen as first-line treatment was demonstrated to be tolerable, with promising anti-tumor activity in mPC. The identified biomolecular markers revealed potential to guide precision treatment of PAAG for mPC. Clinical trial information: NCT05493995 .

Efficacy and safety of regorafenib plus ICIs as second-line treatment in advanced HCC post-frontline treatment failure: A real-world study from a single center.

e16141 Background: Tyrosine kinase inhibitor or bevacizumab (TKI/Bev) combined with immune checkpoint inhibitors (ICIs) currently represent the preferred frontline therapy for patients with Hepatocellular Carcinoma (HCC). Despite this, clinical evidence guiding therapeutic choice for patients unresponsive to this initial immunotherapy regimen remains scarce. This real-world study aimed to assess the efficacy and safety of regorafenib combined with ICIs in patients with HCC who have exhibited disease progress during treatment with TKI/Bev plus ICIs. Methods: This retrospective analysis encompassed a cohort of patients who transitioned to a combined regimen of regorafenib and immune checkpoint inhibitors (ICIs) after the progression of hepatocellular carcinoma (HCC) following treatment with tyrosine kinase inhibitors (TKIs) or a combination of bevacizumab and ICIs, from January 2019 to November 2023. Key efficacy metrics included overall response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). The adverse events (AEs) were systematically classified in accordance with the Common Terminology Criteria for Adverse Events, version 5.0 (CTCAE v5.0). Results: A total of 37 patients were included; 56.8% were Child-Pugh A and 43.2% were Child-Pugh B. Treatment regimens prior to regorafenib and ICIs were lenvatinib plus ICIs in 83.8% of patients, sorafenib plus ICIs in three patients, apatinib plus ICIs, donafenib plus ICIs, and bevacizumab plus ICIs each in one patient. The ORR was 27.0% (10/37), and the DCR was 92.0% (28/37) according to mRECIST criteria. The median PFS was 7.8 months (95% CI, 6.0-9.6). The 6-month and 12-month PFS rates was 60.6% (95% CI, 46.4-79.2) and 40.0% (95% CI, 26.0%-61.6%). The median OS post-regorafenib and ICIs was 16.3 months, with 12-month and 24-month OS rates of 67.0% and 49.7%, respectively. The median OS since first-line treatment initiation was 35.8 months, with OS rates of 94.4% and 72.3% at 12-month and 24-month since first-line treatment initiation, respectively. Subgroup analysis indicated no statistical significance in median PFS between patients with lung metastasis and those without lung metastasis [3.9 months (95% CI, 3.0-4.8) vs 7.80 months (95% CI, 6.1-9.5); P=0.178], but there was a trend toward survival benefit in patients without lung metastasis. Grade 3-4 adverse events were reported in 16.22% of the patients, with no treatment-related fatalities. Conclusions: Regorafenib with ICIs is a promising and tolerable second-line treatment for advanced HCC after initial therapy failure.

Temozolomide and nivolumab in patients with refractory metastatic melanoma (MM).

e21521 Background: Immune checkpoint inhibitors (ICI) are the standard treatment for patients (pts) with MM. However, only a subset of pts respond to ICIs. Temozolomide (TEM) is used in refractory settings but with low objective response rates and no clear overall survival benefit. The efficacy of combined ICI + TEM is not well described. Methods: This was a single center, retrospective study of pts with MM who received treatment with nivolumab (NIVO) and TEM or TEM alone between 11/6/2013 and 11/6/2023. Demographic information, disease characteristics, LDH, treatment, toxicity, objective response, and outcomes were collected. Results: 34 patients were included. 16 were treated with NIVO + TEM and 18 were treated with TEM alone. In the NIVO + TEM group, 81% were male (n = 13) with median age of 59.5 years (range 20-79), and in the TEM group, 56% were male with median age 61 (range 35-81). For NIVO + TEM, 31% had partial response (PR; n = 5), 6% had stable disease (SD, n = 1), and 63% had progressive disease (PD; n = 10). For TEM, 11% had PR (n = 2), 22% had SD (n = 4), and 67% had PD (n = 12) (p = 0.37). For NIVO + TEM, 2 PRs were durable, ongoing at 442 and 741 days; 3 PRs were transient (85-179 days); 1 pt had durable SD ongoing at 201 days. For TEM, PR durations were 173 and 504 days, and SD durations between 213-435 days. Five pts with PD treated with NIVO + TEM had mixed responses (31%) compared with 1 pt treated with TEM (6%). Median progression free survival (PFS) was 80 days (range 11-748) for NIVO + TEM and 55.5 days (7-415) for TEM (p = 0.31). Median overall survival (OS) was 160 days (43-363) for NIVO + TEM and 118 days (7-1938) for TEM (p = 0.15). There were 26 adverse events (AEs) for NIVO + TEM (27% grade 1, 42% grade 2, 19% grade 3, and 12% grade 4; thrombocytopenia and pneumonitis), and 25 AEs for TEM (40% grade 1, 40% grade 2, 12% grade 3, and 8% grade 4; thrombocytopenia) [p = 0.64]. Conclusions: NIVO + TEM occasionally produced durable responses, although outcome metrics were not clearly superior to TEM alone in this small study. Further studies should quantify the benefit of ICI + chemotherapy regimens in refractory MM. [Table: see text]

Efficacy and safety of PARP inhibitors (PARPi) with immune checkpoint inhibitors (ICI) in metastatic castration-resistant prostate cancer (mCRPC): A systematic review and single-arm meta-analysis.

e17053 Background: Recent therapeutic advances in prostate cancer have allowed patients with metastatic disease to live longer and better, especially in the castration sensitive setting. Although improvements have been observed in the castration resistant space, survival in this setting remains suboptimal. Early-phase clinical trials suggest the combination of PARP inhibitors (PARPi) and immune checkpoint inhibitors (ICI) have synergistic effect by modulating the tumor microenvironment. In this systematic review and meta-analysis, we assessed the efficacy and safety of PARPi and ICI in the metastatic castration-resistant prostate cancer (mCRCP) setting. Methods: Pubmed, Cochrane and EMBASE were systematically searched from inception through December 10, 2023. Randomized and non-randomized clinical trials evaluating PARPi + ICI in mCRPC were included. PSA response rate (PSArr), radiographic progression-free survival (rPFS), objective response rate (ORR) and overall survival (OS) were analyzed. Subgroups according to (HRR) were assessed. We also pooled the prevalence of immune-related adverse events (irAE) and their corresponding 95% confidence intervals (95% CI). Statistical analysis was performed using R software version 4.3.2 and heterogeneity was evaluated through I2 statistics. Results: We screened 1070 reports, and six trials met the inclusion criteria (one phase III RCT and 5 phase I/II non-RCT), involving 799 participants. The overall ORR was 8.48% (95% CI 6.48-10.86 I2 0%). About 19% of patients achieved an PSArr (95% CI 9.51-32.50 I2 75%). Median OS was 15.8 months (95% IC 13.9-15.8), and rFPS was 4.5 months (95% IC 4.4-4.9). In patients harboring HRR mutations, PSArr was 17.53% (95% CI 10.43-27.95 I2 75), while in HRR non-mutated it was 10.49% (95% CI 5.89-17.99 I2 0%). The frequency of any-grade irAEs was 21.12% (95% CI 12.34-33.74 I2 85%), with 6.70% of grade 3-4 irAEs (95% CI 3.09-13.91 I2 80%). Hypothyroidism rate was 8.53% (95% CI 5.86-12.27 I2 29%) and adrenal insufficiency was 2.80% (95% CI 1.81-4.30 I2 0%). Conclusions: This meta-analysis results suggest that the combination of PARPi plus ICI in patients with mCRPC is safe and may benefit mainly patients with HRR mutations. Further studies in biomarker selected patients are needed. [Table: see text]

Immuno-based conversion therapy for survival in initially unresectable locally advanced or oligometastatic gastric cancer: A retrospective real-world study with multi-omics analysis.

e16109 Background: Neoadjuvant immune checkpoint inhibitors (ICIs) have shown certain effectiveness in resectable gastric cancer (GC), but the efficacy of conversion ICIs in initially unresectable locally advanced or oligometastatic GC is unclear, particularly regarding efficacy prediction and drug resistance mechanisms through multi-omics analysis. Methods: This is a single-arm, retrospective real-world study to evaluate the efficacy of ICI-containing neoadjuvant/conversion treatment for patients with unresectable locally advanced or oligometastatic GC. Primary endpoints included complete pathological response (pCR) rate, major pathological response (MPR) rate, and R0 resection rate. Secondary endpoints were overall survival (OS), disease-free survival (DFS), progression-free survival (PFS), and safety. Exploratory endpoint was the correlation between tumor genetic characteristics and treatment efficacy. Results: Of the 73 included patients, including 64.4% stage cIVa and 10.9% cIVb, 60 (82.2%) underwent radical surgery after conversion combination treatment. The pCR and MPR rates were 28.6% (95% CI 17.1–40.0%), 42.9% (95% CI 30.3–55.4%), with median DFS/PFS at 30.9 (95% CI 16.0-NA) and mOS at 41.3 (95% CI 23.9-NA) months. The stage IV patients achieved 76.4% R0 resection rate, 24.4% pCR rate, and 40.0% MPR rate, with significantly longer OS for R0 patients versus non-R0 ones (HR: 0.22, 95% CI 0.07-0.70, P = 0.0002), and 1-year OS rate 95.2% vs. 64.2%, the 2-year OS rates 71.1% vs. 9.2%, respectively. Even the mOS of stage IV nonMPR patients are significantly prolonged than that of nonR0 ones, indicating that the implementation of R0 surgery was more crucial than MPR. For stage IV patients of R0-MPR, R0-nonMPR and nonR0, the the 3-year OS rates were 85.0%, 51.3%, and near 0, respectively. Subgroup analysis identified significant correlations between pathological responses and pathological type, PD-L1 expression, and tumor mutational burden. The toxicity and post-surgery complications were manageable. Multi-omics analysis revealed that KMT2D mutations were associated with improved clinical outcomes and enhanced immune responses, while tumor cytochrome P450 was linked to treatment resistance. Additionally, an efficacy-predictive model PEMIT was established using an 8-gene panel and was confirmed to surpass common biomarkers such as PD-L1, tumor mutational burden, and mismatch repair status. Conclusions: ICIs-based neoadjuvant/conversion therapy demonstrated promising survival benefits and acceptable safety profiles for patients with unresectable locally advanced and oligometastatic GC, providing a valuable treatment option for this population. Multi-omics findings uncovered mechanisms of drug resistance and provided potential efficacy-related biomarkers.

Effect of novel autologous immune training platform on end-stage patients with cancer.

2546 Background: SUPLEXA therapeutic cells are the initial autologous and non-engineered candidate to emerge from the novel ENLIST cells training platform. Manufacturing is robust, reproducible and with an acceptable cost of goods. The method requires 35 days to produce multiple doses. Multiple mechanisms of SUPLEXA therapeutic cells have been delineated and all appear to complement that of immune checkpoint inhibitors (ICIs) with SUPLEXA cells serving to enhance the number of primed anti-tumor host T cells while ICIs serve to increase the durability of primed T cells by blocking their premature down-regulation. Methods: A 35 patient Phase 1 single-agent study survey study is currently ongoing in Australia to test the safety and clinical activity of SUPLEXA cells in end-stage patients with various tumor types. No chemo preconditioning or concomitant cytokine treatment was employed. CYTOF analysis of longitudinal peripheral blood is used to monitor changes to the host immune system. Results: To date, SUPLEXA therapeutic cells have demonstrated safety and significant clinical benefit with an observed CR, PR, and many durable SD in approximately half the patients. Several solid tumor patients remain on study beyond 1 year and doing well. Longitudinal analysis of PBMCs from SUPLEXA cell treated cancer patients demonstrated durable changes in the composition of myeloid immune cell subsets in SUPLEXA treated patients, impacting the anti-tumor bias of the host immune system. Specifically, we identified a dramatic decrease in the number of peripheral myeloid derived suppressor cells (MDSCs), within 3 weeks of SUPLEXA treatment. In patients with CR and PR, we also identified stable increases in activated classical CD14+ blood monocytes. Conclusions: SUPLEXA therapeutic cells are a highly differentiated approach to cellular therapy. The first-in-human experience demonstrated a pristine safety profile and strong clinical benefit as a single-agent. The pharmacodynamic decrease of in the number of MDSCs, known to suppress the anti-tumor immune response and limit immune checkpoint inhibitors (ICIs) efficacy, supports the further clinical testing to test the hypothesis that the multiple mechanisms of SUPLEXA cells will enhance the clinical activity of ICIs. Clinical trial information: NCT05237206 .

Artemin and immune checkpoint inhibitor (ICI) efficacy in metastatic colorectal cancer (mCRC): A correlative analysis of the Canadian Cancer Trials Group (CCTG) CO.26 trial.

Artemin and immune checkpoint inhibitor (ICI) efficacy in metastatic colorectal cancer (mCRC): A correlative analysis of the Canadian Cancer Trials Group (CCTG) CO.26 trial.

Intrapatient variation in PD-L1 expression and tumor mutational burden and the impact on outcomes to immune checkpoint inhibitor therapy in patients with non-small-cell lung cancer

Programmed death receptor ligand 1 (PD-L1) tumor proportion score (TPS) and tumor mutational burden (TMB) are key predictive biomarkers for immune checkpoint inhibitor (ICI) efficacy in non-small-cell lung cancer (NSCLC). Data on their variation across multiple samples are limited. Patients with NSCLC and multiple PD-L1 TPS and/or TMB assessments were included. Clinicopathologic and genomic data were analyzed according to PD-L1 and TMB variation. In total, 402 PD-L1 sample pairs and 413 TMB sample pairs were included. Concordance between pairs was moderate for PD-L1 (ρ= 0.53, P < 0.0001) and high for TMB (ρ= 0.80, P < 0.0001). Shorter time between biopsies correlated with higher concordance in PD-L1, but not in TMB. Major increases (ΔTPS ≥+50%) and decreases (ΔTPS ≤-50%) in PD-L1 were observed in 9.7% and 8.0% of cases, respectively. PD-L1, but not TMB, decreased with intervening ICI (P= 0.02). Acquired copy number loss of CD274, PDCD1LG2, and JAK2 were associated with major decrease in PD-L1 (q < 0.05). Among patients with multiple PD-L1 assessments before ICI, cases where all samples had a PD-L1 ≥1%, compared to cases with at least one sample with PD-L1 <1% and another with PD-L1 ≥1%, achieved improved objective response rate and progression-free survival (PFS). Among patients with at least one PD-L1 <1% and one ≥1% before ICI, cases where the most proximal sample was PD-L1 ≥1% had longer median PFS compared to cases where the most proximal PD-L1 was <1%. Among patients with multiple TMB assessments before ICI, patients with a TMB ≥10 mut/Mb based on the most recent assessment, as compared to those with a TMB <10 mut/Mb, achieved improved PFS and overall survival to ICI; instead, no differences were observed when patients were categorized using the oldest TMB assessment. Despite intrapatient concordance in PD-L1 and TMB, variation in these biomarkers can influence ICI outcomes, warranting consideration for reassessment before ICI initiation when feasible.

Comparison of tumor immune microenvironments (TIMEs) between primary and metastatic sites (Mets) in triple-negative breast cancer (TNBC).

1097 Background: The TIME is critical in determining response to immune checkpoint inhibitors (ICIs), but TIME differences across primary and mets in TNBC are not well understood. Since ICIs are standard of care for patients with TNBC, we studied the TIMEs of primary TNBC and mets to investigate how immune composition may affect ICI efficacy. Secondary analysis stratified cohorts by race and disease sites to compare TIMEs in Black or African American (B/AA) with White patients, since TNBC has a high prevalence of B/AA women who are underrepresented in studies and have a worse prognosis. Methods: We retrospectively analyzed de-identified next-generation sequencing data from TNBC patients (n=1,044) in the Tempus Database. Tumors from primary breast (PB, n=553), liver (n=153), lymph node (LN, n=174), lung (n=111), and bone (n=53) sites were sequenced with the Tempus xT DNA (648-gene panel) and xR RNA assays. Histologies included invasive ductal carcinoma (82%), lobular carcinoma (2.2%), mixed ductal and lobular carcinoma (1.7%), and other (14%). Demographics, TMB, MSI, PD-L1, and proportions of B, T (CD4+, CD8+), NK cells, and macrophages were compared across sites. LN were used as a positive control. Chi-squared/Fisher’s exact or Kruskal-Wallis tests were used to assess statistical significance (two-sided, evaluated at the 0.05 alpha level). Results: The cohort (median age=57 years, IQR 46-66) comprised a diverse population (65% White, 23% B/AA, 2.8% Asian, and 9.3% other). Liver exhibited a lower percentage of B cells and higher percentage of macrophages compared to PB (p&lt;0.0001 for both), lung (p&lt;0.0001 for both), and bone (B cells p&lt;0.0001, macrophages p&lt;0.05). Liver also exhibited lower percentages of CD8+ T cells compared to PB (p&lt;0.05) and CD4+ and NK cells compared to lung (CD4+ cells p&lt;0.01, NK cells p&lt;0.0001). Bone had lower percentages of CD8+ cells compared to PB (p&lt;0.0001), lung (p&lt;0.001), and liver (p&lt;0.01). Compared to lung, bone had a lower percentage of CD4+ cells (p&lt;0.0001) and higher percentage of macrophages (p&lt;0.01). PD-L1 positivity, TMB, and MSI exhibited no differences across sites. Secondary analysis compared the TIME between B/AA and White cohorts in PB (B/AA n=85 vs White n=204: %B cells, 15 vs 11, p=0.017; %CD8 cells, 4.9 vs 7.3, p=0.025), liver (B/AA n=15 vs White n=48: %B cells, 8 vs 4, p=0.2; %CD4, 23 vs 14, p=0.2; %CD8, 7.2 vs 4.6, p=0.07), and lung (B/AA n=9 vs White n=33: %B cells, 22 vs 11, p=0.021; %CD8, 7.9 vs 5.2, p=0.5). Conclusions: Compared to PB and lung, liver and bone had immune cell infiltrates indicating a less immunogenic TIME in the overall TNBC population. Although limited by sample size, this is one of the first studies to assess the TIME across race and sites of disease. These findings are hypothesis generating and provide further rationale to better understand how the TIME across disease sites and race may alter the efficacy of ICIs in TNBC.

Concordance of PD-L1 combined positive score (CPS) analysis between primary gastric cancer and matched peritoneal metastasis.

e16068 Background: Peritoneum represents one of the most common metastatic sites of gastroesophageal adenocarcinoma (GEA) and is associated with poor prognosis. Programmed death-ligand 1 (PD-L1) expression is a recognized predictive biomarker of response to immune checkpoint inhibitors (ICIs) in the first-line setting. However, data from pivotal trials showed poorer clinical efficacy of ICIs in the sub-set of patients with peritoneal involvement, regardless of PD-L1 score magnitude. Here, we investigated the temporal and spatial heterogeneity of PD-L1 expression between primary tumor and matched peritoneal metastasis. Methods: PD-L1 expression according to CPS was determined by immunohistochemistry using VENTANA PD-L1 (SP263) assays on formalin-fixed paraffin-embedded (FFPE) tumor tissues derived from 22 patients treated at our institution for advanced GEA from September 2015 to August 2023. Concordance rate of PD-L1 expression between primary tumor and matched peritoneal metastasis using PD-L1 CPS cut-off of 1 and 5 was reported (spatial heterogeneity); additionally, concordance between PD-L1 value before and after the administration of systemic treatments was analyzed (temporal heterogeneity). Results: 12(54.5%)/5(22.7%) primary tumor samples and 12(54.5%)/1(4.5%) peritoneal metastases showed PD-L1 CPS ≥ 1/ ≥ 5, respectively. Concordance of PD-L1 CPS between primary and peritoneal specimens was 54.5% and 72.7% according to CPS cuts-off of 1 and 5, respectively, highlighting marked spatial heterogeneity. High concordance rate (94%) was reported between negative PD-L1 CPS primary tumor samples and matched peritoneal metastases, against the cut-off of CPS ≥ 5; in contrast, none of the positive primary tumor samples retained PD-L1 expression in the peritoneum. Evident temporal heterogeneity of PD-L1 expression was also observed, with 56% concordance against CPS ≥ 5 in the pre- versus post-treatment comparison. Conclusions: PD-L1 expression in GEA is characterized by spatial and temporal heterogeneity which is more prominent for lower CPS cut-offs values. This evidence could hamper its role as predictive biomarker for ICIs. The high intra-patient discordance rate of PD-L1 CPS expression between positive primary tumor samples and matched peritoneal metastases suggests that peritoneal specimens should not be recommended as the preferred source for PD-L1 assessment.

Impact of time-of-day infusion of camrelizumab combined with chemotherapy on efficacy in advanced malignant tumors.

e14634 Background: The combination of immune checkpoint inhibitors (ICIs) with chemotherapy has emerged as a standard first-line treatment strategy for advanced cancers. Camrelizumab and Tislelizumab, representative ICIs, have approval by the Chinese NMPA for first-line treatment of advanced cancers such as lung cancer and esophageal cancer. Previous studies have indicated that the timing of drug administration can influence the efficacy of ICIs. However, studies on the ICIs plus chemotherapy are lacking. Therefore, we conducted a retrospective study to explore the effect of the timing of infusion on patients with advanced cancer undergoing treatment with ICIs combined chemotherapy. Methods: We retrospectively enrolled a total of 253 patients diagnosed with advanced cancers between 2017 and 2023 in Guangdong Second Provincial General Hospital. Among these patients, 109 received camrelizumab (Cam cohort) plus chemotherapy and 65 received tislelizumab (Tis cohort) plus chemotherapy. Patients were grouped into morning (AM) and afternoon (PM) categories based on the timing of their ICIs administration (&lt; 1 times versus ≥ 1 times after 16:00). The Response Evaluation Criteria in Solid Tumors Criteria V.1.1 was used to evaluate the response to treatment. The primary endpoint was progression-free survival (PFS). Results: The results consistently showed that the PM group had a longer PFS than the AM group in the overall patients (p &lt; 0.01). In the Cam cohort, the PM group (n = 48) exhibited a longer PFS compared to the AM group (n = 61) (16.8 months vs. -, p = 0.02). However, no significant difference in PFS was observed among patients in the Tis cohort (AM vs. PM, n = 34 vs. n = 31, 16.1 months vs. -, p = 0.51). Subgroup analyses indicated that the PM group had a more favorable PFS treatment effect in most subgroups. The incidence of any Treatment Emerged Adverse Event (TEAE) (Cam cohort, AM vs. PM, 98.52% vs. 92.68%; Tis cohort, AM vs. PM, 97.05% vs. 100.00%) and grade 3 TEAEs (Cam cohort, AM vs. PM, 5.80% vs.7.30%; Tis cohort, AM vs.PM - vs. 12.90%) was similar in the Cam cohort and Tis cohort. The most common adverse events are anemia (Cam cohort vs. Tis cohort, 70.58% vs. 79.41%), thrombocytopenia (Cam cohort vs. Tis cohort, 54.41% vs. 58.82%) and lymphopenia (Cam cohort vs. Tis cohort, 44.11% vs. 44.11%). Conclusions: The findings of this study highlight a significant variation in daily rhythms among advanced cancer patients undergoing treatment with ICIs plus chemotherapy. Interestingly, a trend was observed in patients treated with camrelizumab, where those receiving treatment in the afternoon demonstrated a longer PFS. However, this trend was not observed in patients treated with tislelizumab. These results suggest that time-of-day infusion could potentially serve as a personalized strategy for patients treated with combination ICIs therapy.

A phase 2 trial of IO102-IO103 and nivolumab-relatlimab fixed-dose combination in previously untreated, unresectable melanoma.

TPS9605 Background: One emerging strategy to augment immune checkpoint inhibitor efficacy is to eliminate immunosuppressive cell populations in the tumor microenvironment (TME) through vaccination. IO102-IO103 is an investigational cancer vaccine that targets both tumor and immune-suppressive cells in the TME. IO102-IO103 treatment promotes inflammation and potentiates anti-tumor activity via activation and expansion of T cells against IDO1 and/or PD-L1 positive cells. IO102-IO103 plus nivolumab demonstrated an impressive objective response rate (ORR) of 80% in the phase 1/2 MM1636 trial of 30 patients with previously untreated, unresectable melanoma, and a randomized phase 3 trial of pembrolizumab with or without IO102-IO103 (NCT05155254) is ongoing. No prior studies have evaluated IO102-IO103 in combination with dual PD-1 and LAG-3 blockade with nivolumab-relatlimab (nivo-rela), and to our knowledge there are no existing clinical data for other investigational agents in combination with nivo-rela. Methods: NCT05912244 is a single-arm, investigator-initiated trial testing IO102-IO103 in combination with nivo-rela in patients with previously untreated, unresectable melanoma. Twelve of forty-three planned patients have been enrolled. All patients will be treated with nivo-rela every four weeks for up to two years. IO102-IO103 will be administered subcutaneously every two weeks for the initial eight weeks, and then every four weeks for up to two years. An interim efficacy analysis for futility will be performed after response data are available for 21 patients. Eligible patients must have histologically confirmed, unresectable stage III or stage IV non-uveal melanoma, measurable disease by RECIST v1.1, an ECOG performance status of 0 or 1, and definitive treatment of any brain metastases. Prior systemic treatment in the neoadjuvant or adjuvant setting is allowed if completed at least six months prior to trial enrollment. Available pre-treatment melanoma tissue is required, and all patients will undergo an on-treatment study biopsy between the second and third dose of nivo-rela. Peripheral blood mononuclear cells will be collected prior to the first three doses of nivo-rela. The primary endpoint is ORR by RECIST v1.1, weighted by PD-L1 expression. Secondary endpoints include safety assessed by Common Terminology Criteria for Adverse Events v 5.0, progression-free survival (PFS) by RECIST v1.1, duration of disease response, and disease control rate. Exploratory correlative endpoints include assessment of changes in PD-L1 and IDO-expressing cells in the TME on paired tumor biopsies, identification of peripheral PD-L1 and IDO-reactive cells in the peripheral blood by ELISpot, and assessment of peripheral pre-treatment and on-treatment T cell clonality by TCR sequencing. Clinical trial information: NCT05912244 .

Analyzing the gut microbiome in adolescent and young adult patients with melanoma receiving immune checkpoint blockade.

9563 Background: Melanoma is the third most common cancer in adolescent and young adults (AYA), a unique cohort defined as patients between 15-39 years of age per the National Cancer Institute. Immune checkpoint inhibitors (ICI) have changed the landscape for advanced melanoma treatment, and the gut microbiota has been shown to remodel the tumor microenvironment to improve ICI efficacy. There is a paucity of research in this cohort, however studies show that AYA patients, in general, have historically not seen the same survival gains as other age groups. Furthermore, literature shows that survival was much worse for AYA's with stage IV melanoma than observed among older adults. Methods: The AYA cohort in this retrospective review is from the 2021 Science publication entitled "Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response". This cohort was matched on a 2:1 basis with older non-AYA patients 50-70 years of age. We controlled for sex, BMI, race, treatment naivety, stage of disease, as well as smoking, drug, and alcohol status. Results: Our AYA cohort of 23 patients is comprised of 15 females, 22 Caucasians, 20 with primary cutaneous melanoma, 12 with stage III at the start of treatment and 11 with stage IV, 17 were BRAF positive, 8 received combined immunotherapy, 20 were treatment naïve, and 11 were responders. We found no difference in alpha or beta diversity in AYA and older non-AYA patients, however alpha diversity increased with age. This is consistent with literature regarding aging gut microbiomes. Furthermore, we noted the most common microbes found between these groups varied considerably. Using differential analyses, we found, for example, a higher abundance of Ruminococcaceae, at the family level, in older non-AYA patients and a higher abundance of Bacteroides stercoris in AYA patients. Literature shows the relative abundance of Ruminococcaceae increased with age and was significantly higher in older patients. Furthermore, Bacteroides stercoris correlates positively with fiber, grain, and vegetable intake. Additionally, Blautia massiliensia, Blautia obeum, and Dorea longicatena were found to be significantly more prevalent (p=0.010, p=0.34, and p=0.035, respectively)) in older non-AYA patients. These species are all known to be obesity biomarkers. Conclusions: We found that the gut microbiota of AYA and older non-AYA melanoma patients differ. Older non-AYA patients have bacterial species associated with negative biomarkers which may be due to an aging gut microbiome. Establishing microbial features in the AYA population can help with microbiome modulation as a therapeutic strategy. Enriching modalities include fecal microbiota transplantation, probiotics, and improving diet as well as fiber intake. Further research should explore if the gut microbiome influences worse outcomes in AYA's with late stage melanoma.

Comprehensive analysis of TMB, TNB, and HLA via NGS sequencing in a large cohort of Chinese pan-cancer patients.

2656 Background: Evidence suggests that patients with high tumor mutational burden (TMB) and tumor neoantigen burden (TNB) are more likely to benefit from Immune checkpoint inhibitors (ICIs). Furthermore, loss of heterozygosity (LOH) in human leukocyte antigen (HLA) alleles, particularly HLA class I, impairs neoantigen presentation and contributes to resistance against ICIs. This study provides real-world insights into the distribution of TMB, TNB, and HLA variations within a large cohort of Chinese patients with various cancers. Methods: From 2021 to 2023, we performed a retrospective analysis on 1603 cancer patients, examining genetic mutations and HLA traits using the Med1 CDx DNA-based NGS panel targeting 601 cancer-related genes and HLA class I. TMB was calculated as the average number of coding mutations per megabase of the genome. HLA class I alleles (HLA-A, B and C) were identified and predicted using the OptiType and pVACtools software suites. TNB was defined as the number of high-affinity (IC50 ≤ 50 nM) neoantigens per megabase of the genome. Statistical analyses were performed to explore the relationship between TMB, TNB, and LOH status in critical regions of HLA. Results: This study enrolled participants across 25 cancer types. With 32.56% having non-small cell lung cancer (NSCLC), 11.79% colorectal carcinoma (CRC), and 18.34% unidentified solid tumors. The remaining 37.31% comprised cases of cholangiocarcinoma, hepatocellular carcinoma, pancreatic cancer, etc. High-affinity neoantigen-generating genes such as TP53, EGFR, KRAS, LRP1B, DMD, and FAT1 were identified. Our findings indicate substantial variation in tumor neoantigen burden (TNB) across various cancer types and even among different samples within the same type. Neuroendocrine tumors exhibited the highest TNB at 4 neoantigens/Mb, followed by esophageal cancer (3.3), melanoma and urothelial carcinoma (2.67 each), indicating higher TNB levels in these cancers compared to others. A significant positive correlation was observed between TMB and TNB (p&lt; 0.0001). Analysis revealed no significant TNB differences attributable to age (cutoff at 60 years) or gender. However, individuals aged over 70 years demonstrated a higher TNB of 4 compared to those under 70 with 3.33, highlighting potential age-related differences in TNB. Conclusions: Our analysis highlights significant variation in TNB across cancer types, with the highest TNB found in neuroendocrine tumors and the lowest in gastrointestinal stromal tumors, indicating TNB's value as a biomarker for optimizing ICI therapy. Furthermore, we found that people over 70 years old have higher TNB levels than younger individuals, suggesting a potential for improved ICI efficacy without chemotherapy. The evident strong correlation between Tumor Mutational Burden (TMB) and TNB underlines their crucial role in the success of cancer immunotherapy.

Multiplex analysis of the immune environment before and after neoadjuvant durvalumab as a prognostic factor in resectable non-small cell lung cancer (NSCLC) in the IFCT-1601 IONESCO phase 2 trial.

8022 Background: Immune checkpoint inhibitors (ICI) are currently included in the peri-operative standard of care for NSCLC with the objective of a curative strategy. In early stages of NSCLC, biomarkers predicting ICI efficacy should be more stringent than PD-L1 tumoral expression in order to improve the benefit-toxicity ratio. We deeply analyzed the tumor microenvironment of patients included in the IONESCO multicenter phase 2 trial (stage IB &gt; 4cm–IIIA, non N2 resectable NSCLC). Diagnostic biopsies and surgical resection specimen after 3 cycles of Durvalumab were available. We previously showed that the % of residual viable tumor cells (RVT) was associated with disease free survival (DFS) and overall survival (OS). PD-L1 tumor positive score was not correlated to RVT nor survival. Methods: 46 patients were included in the IONESCO trial. Among them, diagnostic biopsy (n = 32), surgical resection specimen post durvalumab (n = 39) and paired tumor samples (n = 31) were analyzed. Immune environment was assessed using 7 quantitative 7-plex immunofluorescence panels generating 349 different cellular phenotypes in 3 different compartments (whole tumor, intra cytokeratin and stroma), focusing on T and B lymphocytes, macrophages, immune checkpoint, NK cells, apoptosis, innate and adaptive immunity, dendritic cells. Densities of cells were quantified using Fluorescent Multiplex immunohistochemistry performed on Leica Bond RX, using OpalTM technology. A fisher's exact test or chi2 test was used for demographics variables and RVT. HRs and 95% CIs were estimated using a Cox model. NCT number: NCT03030131. Results: With median follow-up of 4.5 years, 16/31 patients had a disease recurrence. Histology, sex, stage and survival were significantly associated with intra-tumor densities of CD3, CD8, PD1, TIM3, and CD163 cells in the diagnostic biopsy, and with the delta of CD3, FoxP3, CD4, CD163PD1, TIM3, PDL1 on immune cells and TIM3PDL1 cells, between biopsy and surgical specimen. DFS was significantly associated with high density of CD8+TIM3+ in biopsies (HR = 0.25 [0.09-0.71], p = 0.0092) and with the high density of CD20+ cells in surgical specimen (HR = 0.36 [0.13-0.97], p = 0.04). The RVT was significantly associated with CK+Caspase3- cells and CK+PDL1+ cells in the surgical specimen. No biomarker was associated with OS. Conclusions: Multiparameter analysis of the immune NSCLC environment of patients treated with neoadjuvant anti-PDL1 allows identification of markers associated with clinical, pathological parameters and DFS. Our findings highlight the substantial impact of high CD8+TIM3+ cell density pre-durvalumab and of high CD20+ cell density post-durvalumab on DFS. These findings deserve to be assessed in patients treated with neoadjuvant combined immunotherapy chemotherapy. Clinical trial information: NCT03030131 .

Preliminary results from a FIH, open-label phase 1 study with BMC128, a rationally designed live bacterial consortium, in combination with nivolumab.

8631 Background: Immune-Checkpoint inhibitors (ICI) have transformed the treatment of solid tumors, specifically in cutaneous melanoma, clear cell renal cell carcinoma (ccRCC) and non-small cell lung cancer (NSCLC). Despite these advances, resistance to ICI eventually occurs in many patients. Recent reports have found that patients showing poor response to ICI are characterized by a reduced gut microbiome diversity, suggesting that the gut microbiome might affect immune activation by ICI. BMC128 is a live bacterial consortium of 4 bacterial strains designed to induce anti-tumor immune function when given in conjunction with ICI. These strains were identified by analyzing microbiome data obtained from NSCLC and ccRCC patients presenting varied responses to ICI, using a proprietary computational discovery platform enabling high-resolution functional microbiome analysis. In pre-clinical studies, treatment with BMC128 potentiated the efficacy of ICI in breast cancer and melanoma mouse models, reducing tumor volume, increasing the number of responders, and demonstrating an increase in infiltrating immunocytes: CD4, CD8 and NK cells. The aim of this study was to assess the safety and tolerability of BMC128 in combination with nivolumab. Methods: 12 patients with ccRCC, cutaneous melanoma and NSCLC-adenocarcinoma (EGFR/ALK wild-type) (6, 1 and 5 patients, respectively), who previously progressed on PD1/PDL-1 inhibitors were recruited to this FIH open label phase 1 study. Patients were treated with a daily oral dose of BMC128 4*108 live cells/ strain in combination with nivolumab 480mg q4weeks. The study treatment consisted of 4 stages: depletion with antibiotics, induction with BMC128 monotherapy, combination treatment, and nivolumab monotherapy. Results: No SAEs related to BMC128 were reported throughout the duration of the study. Two patients exhibited minor AEs that were potentially associated with BMC128. At the current time point, 4 out ofthe first 8 patients in the study showed SD and sustained benefit beyond the first imaging timepoint, following the combination treatment. Altogether demonstrating clinical benefit for a total of 16 weeks (2 patients), 24 weeks (1 patient), and 68 weeks (1 patient). Conclusions: BMC128 has demonstrated an excellent safety profile and preliminary beneficial clinical effect. A phase 2 study to investigate the efficacy of BMC128 is planned to be initiated in late 2024. Clinical trial information: NCT05354102 .

Linking the companion diagnostic function of cancer genome profiling to therapy: Investigation of TMB-high predictors.

e13033 Background: Based on the companion diagnostic function of the Comprehensive Cancer Genome Profiling (CGP) test in Japan, pembrolizumab is the standard treatment for patients with Tumor Mutational Burden (TMB)-high (H) solid tumors. In this report, we attempted to extract predictive factors of TMB-H from CGP test results. Methods: We carried out a retrospective cohort study of 42 patients with malignant breast tumors (excluding circulating tumor DNA in the blood) who underwent CGP testing between June 1, 2019, and November 30, 2023, at our hospital and affiliated institutions. We analyzed the association between clinicopathological factors, the number of analyzed cancer-related gene mutations (SNV, InDel), and TMB-H using univariate and multivariate statistical analysis. Results: Of the 42 cases (27 positive and 15 negative for estrogen receptor (ER), respectively), seven (16.7%) were TMB-H. Samples significantly associated with TMB-H according to univariate analysis were submitted as pathology specimens (non-primary (16.7%) vs. primary (0%), p = 0.011), ER (positive (16.7%) vs. negative (0%), p = 0.044), letrozole (LET) (yes (11.9%) vs. no (4.8%), p = 0.008), and previous treatment (after 6th line (14.3%) vs. before (2.4%), p = 0.041). Multivariate analysis showed that LET had a significant effect on TMB-H in Aromatase inhibitor agents (LET + Anastrozole + Exemestane) (LET: OR, 19.9; 95% CI, 2.2–183.5; p = 0.008) and the number of cancer-related gene mutations (PIK3CA+TP53) were significantly affected (PIK3CA: OR, 3.8; 95% CI, 1.1–13.2; p = 0.032. TP53: OR, 0.08; 95% CI, 0.01–0.66; p = 0.015). Single regression analysis showed a significant association between the number of PIK3CA mutations and LET. (β, 0.31; SE, 0.11; p = 0.008). Conclusions: ER positivity, history of LET use, prior therapy after the 6th line, and submission of pathology specimens from non-primary tumors to CGP testing are predictive factors for TMB-H. In multivariate analysis, the history of LET use and the number of PIK3CA mutations were significantly associated with TMB-H. Research shows that PIK3CA mutations are most frequent in patients who have undergone preoperative endocrine therapy with LET (Breast Cancer Res Treat. 2020 Nov;184(1):123–133.), suggesting that an increased number of PIK3CA mutations due to LET contributed to TMB-H. Although immune checkpoint inhibitors (ICIs) are not indicated for ER-positive breast cancer, TMB-H may be a predictor of ICI efficacy in such cases. The limitations of our research were the small sample size, and the study population only included Japanese. For the next steps needed to continue in this research, clinical trials should take place to test whether TMB-H is a predictor of ICIs in a wider population of ER-positive breast cancer.