Immune Checkpoint Inhibitors Treatment In Patients Research Articles

7596 Thyroid Function Tests in Breast Cancer Patients Following Immune Checkpoint Inhibitor Treatment: What Happened in a Population with Preexisting Thyroid Dysfunction?

Abstract Disclosure: M. Villanova: None. L. Min: None. Introduction: Thyroid dysfunction occurs commonly following immune checkpoint inhibition, but the etiology remains unclear. Immune checkpoint inhibitor (ICI) is not contraindicated in patients with a preexisting thyroid dysfunction, but little is known about the impact of ICI on thyroid function tests (TFTs) in this setting. This study sought to define TFTs abnormalities following ICI treatment in patients with previous thyroid dysfunction. Methods: We performed a retrospective cohort study of thyroid dysfunction in patients with breast cancer undergoing anti-programmed cell death protein-1/ligand-1 therapy from May 2016 to Dec 2023. Results: A total of 30 patients were included with a mean follow-up of 18 ± 12 months. Two patients (7%) had a history of Graves’ disease, 4 patients (13%) had a post ablative hypothyroidism, and 3 patients (10%) had a post-surgical hypothyroidism. The etiology of the hypothyroidism was not further specified in the remain cases (70%). Twenty-three patients (77%) were treated with levothyroxine at baseline at the mean dose of 1.31 ± 0.68 mcg/kg. Baseline TFTs were available in 27 patients (90%). Twenty-four patients (80%) had at least one TFTs abnormality after initiating ICI treatment. Subclinical hypothyroidism (n = 11) was the most common abnormality, followed by overt thyrotoxicosis (n = 10), subclinical thyrotoxicosis (n =7), and overt hypothyroidism (n = 7). Thirteen out of 16 patients with normal baseline TFTs developed at least one TFTs abnormality after initiating ICI treatment. Subclinical hypothyroidism (n = 6) and overt thyrotoxicosis (n =6) were the most common alterations, followed by subclinical thyrotoxicosis (n = 5), and overt hypothyroidism (n = 3). Three patients with post-ablative hypothyroidism had normal baseline TFTs. Among these, one patient developed an overt thyrotoxicosis, one patient developed a subclinical hypothyroidism followed by overt thyrotoxicosis and one patient had no TFTs alterations. One post-operative hypothyroid patient had a normal baseline TFT and developed a subclinical hypothyroidism followed by overt thyrotoxicosis. Twenty-five patients (83%) were on levothyroxine at the last follow-up at the mean dose of 1.41 ± 0.60 mcg/kg. The dose was higher than that at baseline but did not reach statistical difference (Student T test, P = 0.059). Levothyroxine dosage was adjusted in 16 patients (53%) and 25 patients (83%) achieved normal TFTs at the last follow-up. Conclusion: ICI treatment related TFTs abnormalities were common in patients with preexisting thyroid dysfunction. There were multiple distinct phenotypes. The mechanisms underlying the TFTs abnormalities is not clear. Destructive thyroiditis, medication adherence, or interference with TFT assay by ICI are among the possible etiologies. ICI is not contraindicated in this group of patients but their TFTs should be monitored closely. Presentation: 6/1/2024

Immune-related [18F]FDG PET findings in patients undergoing checkpoint inhibitors treatment: correlation with clinical adverse events and prognostic implications

BackgroundDirect comparisons between [18F]FDG PET/CT findings and clinical occurrence of immune-related adverse events (irAEs) based on independent assessments of clinical and imaging features in patients receiving immune checkpoint inhibitors (ICIs) are missing. Our aim was to estimate sites, frequency, and timing of immune-related PET findings during ICIs treatment in patients with melanoma and NSCLC, and to assess their correlation with clinical irAEs. Prognostic implications of immune-related events were also investigated.MethodsFifty-one patients with melanoma (47%) or NSCLC (53%) undergoing multiple PET examinations during anti-PD1/PDL1 treatment were retrospectively included. Clinical irAEs were graded according to CTCAE v.5.0. Abnormal PET findings suggestive of immune activation were described by two readers blinded to the clinical data. Progression-free survival (PFS) and overall survival (OS) were analyzed with the Kaplan-Meier method in patients stratified according to the presence of irAEs, immune-related PET findings or both.ResultsTwenty-one patients showed clinical irAEs only (n = 6), immune-related PET findings only (n = 6), or both (n = 9). In patients whose imaging findings corresponded to clinical irAEs (n = 7), a positive correlation between SUVmax and the severity of the clinical event was observed (rs=0.763, p = 0.046). Clinical irAEs occurred more frequently in patients without macroscopic disease than in metastatic patients (55% vs. 23%, p = 0.039). Patients who developed clinical irAEs had a significantly longer PFS than patients who remained clinically asymptomatic, both in the overall cohort (p = 0.011) and in the subgroup of (n = 35) patients with metastatic disease (p = 0.019). The occurrence of immune-related PET findings significantly stratified PFS in the overall cohort (p = 0.040), and slightly missed statistical significance in patients with metastatic disease (p = 0.08). The best stratification of PFS was achieved when all patients who developed immune-related events, either clinically relevant or detected by PET only, were grouped together both in the overall cohort (p = 0.002) and in patients with metastatic disease (p = 0.004). In the whole sample, OS was longer in patients who developed any immune-related events (p = 0.032).ConclusionPatients with melanoma or NSCLC under ICI treatment can develop clinical irAEs, immune-related PET findings, or both. The occurrence of immune-related events has a prognostic impact. Combining clinical information with PET assessment improved outcome stratification.

1353P Efficacy and safety of docetaxel in combination with nintedanib or ramucirumab following immune checkpoint-Inhibitor treatment in patients with non-small cell lung cancer

1353P Efficacy and safety of docetaxel in combination with nintedanib or ramucirumab following immune checkpoint-Inhibitor treatment in patients with non-small cell lung cancer

Predictive value of early dynamic changes of NLR and PLR for the efficacy of immune checkpoint inhibitor in head and neck squamous cell carcinoma

We analyzed the predictive value of dynamic changes in neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) in recurrent and/or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) treated with immune checkpoint inhibitors (ICIs). A total of 104 patients with R/M HNSCC treated with ICIs during August 2018 to June 2023 were included. Dynamic changes were defined as the difference between NLR and PLR on day 1 of cycles 1 and 2. Patients with increased NLR or PLR had an independently increased risk of disease progression at the first response evaluation (odds ratio [OR] 5.26, P = .005; OR 2.29, P = .042), disease progression (hazard ratio [HR] 2.29, P = .003; HR 1.68, P = .027), and death (HR 1.86, P = .027; HR 1.68, P = .037). Furthermore, patients with a decrease in NLR showed longer progression-free survival, with HRs of 0.36 (P < .001) for those with low pre-ICI NLR and 0.52 (P = .041) for those with high pre-ICI NLR, compared to those with increased NLR. Increased NLR or PLR was associated with adverse outcomes after ICI treatment in patients with R/M HNSCC.

Blood based kinase activity profiling to predict response to immune checkpoint inhibitors in patients with advanced stage non-small cell lung cancer: The IOpener study.

e20576 Background: Treatment with immune checkpoint inhibitors (ICI) has become part of the standard of care for patients with advanced stage non-small cell lung cancer (NSCLC). Unfortunately, its success is limited to a subset of treated patients, while ICI treatment is associated with immune-related adverse events. The predictive value of kinase activity profiling of peripheral blood mononuclear cells (PBMCs) was previously shown in a discovery study (Hurkmans et al., JITC 2020). The aim of the current study was to perform a prospective and blinded validation of the predictive value of kinase activity profiles of PBMCs for response to ICI treatment in patients with NSCLC in a standardized setting. Preliminary results for this study were presented before (De Joode et al. 2022), here we present results for a significantly extended validation cohort with a follow-up of at least 1 year. Methods: PBMCs from patients with advanced stage NSCLC included in this observational multicenter study were collected prior to ICI treatment. Tyrosine kinase activity of PBMCs was profiled using a micro-array with 144 different peptide-substrates (Pamchip). Classification analysis was performed to discriminate between patients with or without progressive disease (RECIST v1.1) within 24 weeks after start of treatment. Only patients treated with first-line pembrolizumab ± chemotherapy were included. Results: A predictive model was first established based on kinase activity profiles, determined in a calibration cohort (N = 61) and subsequently applied to an independent validation cohort (N = 136). The predictive accuracy of the model in the validation cohort was 62% (CI95 = 53-70%). Interestingly, the accuracy improved when the model was combined with PD-L1 expression: for patients with a PD-L1 score &lt; 50%, the accuracy for predicting progressive disease at 24 weeks was 68% (CI95 = 57-78%). Here, significant lower progression free survival (PFS) rates were observed for patients for whom progression was predicted compared to those for whom no progression was predicted (p = 0.0003, hazard ratio = 2.6, CI95 = 1.6-4.3).The 1-year PFS for patients with predicted progression was only 13% (CI95 = 5-31%) which implies a NPV of 87%. PFS rates were also lower for patients with predicted progression in the subgroups with PD-L1 score &lt; 1% (p = 0.03, hazard ratio = 2.2, CI95 = 1.1-4.3) and PD-L1 score 1-49% (p = 0.002, hazard ratio = 5.0, CI95 = 1.8-14). The predictive kinase activity signature appears to be T-cell related, which will be further investigated to improve understanding of the underlying biology. Conclusions: In this prospective validation study the predictive value of kinase activity profiling of PBMCs for response to first-line ICI therapy of patients with advanced NSCLC was confirmed. The final aim is to apply the kinome analysis in clinical practice.

Unveiling the role of FTO polymorphisms in predicting response to immune checkpoint inhibitors: A retrospective study

BackgroundIdentifying patients who can benefit from immune checkpoint inhibitors (ICIs) is a critical challenge in immunotherapy. This study aimed to investigate the association between fat mass and obesity-associated protein (FTO) polymorphisms and ICIs treatment outcomes. MethodThis retrospective study was conducted on 371 patients with malignant tumors who received ICIs treatment and were followed-up for a minimum duration of 12 months. Seven variants in FTO gene were genotyped using the Sequenome MassARRAY platform, and their associations with ICIs treatment outcomes were analyzed. ResultsPharmacogenomic research revealed that individuals carrying the rs11075995AT/TT genotype were more likely to benefit from ICIs treatment compare to TT genotype. Cox regression analysis showed that rs1125338TT carriers exhibited a shorter progression-free survival (PFS, hazard ratio (HR) = 1.72, 95 % confidence interval (CI) = 1.12–2.46), while rs12596638GG carriers experienced extended PFS (HR = 0.71, 95 % CI = 0.50–0.99). Multiple Cox regression analysis indicated that rs12596638GG (HR = 6.81, 95 %CI = 1.20–38.56) and rs1125338CC (HR = 1.78, 95 %CI = 0.07–0.45), rs12600192CC (HR = 0.13, 95 %CI = 0.037–0.44) genotypes were independently associated with overall survival (OS) after adjusting clinical characteristics. Furthermore, patients with rs12600192CC genotype had a lower risk of severe irAEs compared to those with GG/GC genotypes (P < 0.01). ConclusionWe identified FTO gene polymorphisms associated with treatment outcomes of ICI treatment in patients with multiple solid cancers, which might serve as potential predictive biomarkers.

The association between baseline TPOAb and/or TgAb positivity and thyroid immune-related adverse events in patients with malignancies following treatment with immune checkpoint inhibitors

Objective: To investigate the association between positive anti-thyroid peroxidase antibody (TPOAb) and/or anti-thyroglobulin antibody (TgAb) and the occurrence of thyroid immune-related adverse events (irAEs) in patients with malignant tumors who treated with immune checkpoint inhibitors (ICIs). Methods: A case-control study. A total of 116 patients with malignant tumor who received ICIs treatment and underwent thyroid function evaluation at Peking Union Medical College Hospital from January 2017 to April 2023 were enrolled retrospectively, including 77 males and 39 females, with a median age of (M(Q1, Q3)) 63.0 (55.0, 70.0) years. The patients were divided into the euthyroid group (n=58) and the thyroid irAEs group (n=58) according to whether thyroid irAEs occurred after ICIs treatment. The clinical characteristics and baseline anti-thyroid antibodies associated with the occurrence of thyroid irAEs after ICIs treatment in patients with malignant tumors were evaluated. Variables with statistical significance in univariate analysis were included in multivariate logistic regression model to analyze the risk factors for thyroid irAEs in patients with malignant tumors who received ICIs treatment. Results: In irAEs group, therewore 4 (3.4%) cases of clinical thyrotoxicosis, 23(19.8%) cases of subclinical thyrotoxicosis, 23 (19.8%) cases of clinical hypothyroidism, and 8(6.9%) cases of subclinical hypothyroidism. The positive rate of anti-thyroid antibodies at baseline in the thyrioid irAEs group was higher than that in the euthyroid group［16/58（27.6%）vs 3/58（5.2%），P=0.001］. After at least one course of ICIs treatment, the incidence of thyroid irAEs in patients with positive anti-thyroid antibodies at baseline was 84.2% (16/19), whereas it was 43.3% (42/97) in patients with negative anti-thyroid antibodies(P=0.001). Univariate logistic regression analysis showed that gender (OR=2.812, 95%CI:1.257-6.293), baseline thyroid autoantibodies were positive (OR=6.984, 95%CI: 1.909-25.547), baseline TgAb positivity (OR=8.909, 95%CI: 1.923-41.280), and baseline TPOAb positivity (OR=7.304, 95%CI: 1.555-34.308) were associated with thyroid irAEs (all P<0.05). Multivariate logistic regression analysis indicated that baseline TgAb positivity (OR=7.637, 95%CI: 1.617-36.072) was a risk factor for thyroid irAEs (P=0.01). Conclusions: The incidence of thyroid irAEs is higher in patients who are positive for baseline TPOAb and/or TgAb compared to those who are negative for TPOAb and TgAb. Patients with positive TgAb at baseline are at high risk of developing thyroid irAEs.

Abstract 7527: Investigating biomarkers for immune-related adverse events following immune checkpoint inhibitor therapy in recurrent lung cancer patients

Abstract Background: The application of immune checkpoint inhibitors (ICIs) as adjuvant therapy post-lung cancer surgery is expected to confer significant benefits. However, the risk factors for severe immune-related adverse events (irAEs) remain incompletely understood, and managing irAEs may require long-term steroid use. The identification of biomarkers for irAEs in patients with surgically resected lung cancer is an urgent need. Methods: We analyzed 43 lung cancer patients who received ICI treatment for recurrence postoperatively. Macrodissection of lung cancer lesions was performed on FFPE specimens from resected lungs, from which total RNA was extracted. We conducted gene expression analysis of 770 immune-related genes using the PanCancer Immune Profiling Panel (NanoString Technologies, Inc., Seattle, WA, USA). The relationship between gene expression changes and irAEs or the efficacy of ICI treatment was examined. For validation, immunostaining of proteins strongly associated with irAEs was performed to determine their expression status in tissue specimens. Results: Among the 43 patients (30 males, 13 females, median age 68), 28 had adenocarcinoma, and 15 had squamous cell carcinoma. PD-L1 positivity was observed in 36 patients. The treatment regimens included pembrolizumab monotherapy for 18 patients and combination immunotherapy for 25 patients, with 25 patients responding to treatment and 7 developing irAEs. There was a marked difference in gene expression between adenocarcinoma and squamous cell carcinoma, with a notably higher number of tumor-infiltrating lymphocytes (TILs) in adenocarcinoma. An increase in TILs was observed in cases with irAEs across both cancer types. Additionally, an increased CD8/Treg ratio and CD8/exhausted T cell ratio were noted in adenocarcinomas with irAEs. A strong correlation between IRF5 gene expression and the occurrence of irAEs in adenocarcinoma was also confirmed by immunohistochemistry. Conclusion: We have identified tumor immune microenvironments correlated with the onset of irAEs following ICI treatment in patients with postoperative recurrence of lung cancer. This discovery could contribute to perioperative treatment strategies and improve our understanding of tumor immune mechanisms. Citation Format: Yujin Kudo, Jun Matsubayashi, Satoshi Takahashi, Masaru Hagiwara, Masatoshi Kakihana, Toshitaka Nagao, Tatsuo Ohira, Norihiko Ikeda. Investigating biomarkers for immune-related adverse events following immune checkpoint inhibitor therapy in recurrent lung cancer patients [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 7527.

Abstract 3852: Comprehensive genomic profiling of recurrent or metastatic head and neck cancer presenting with combined positive score 90 or more

Abstract Background. Biomarkers that predict response to immune checkpoint inhibitor (ICI) in recurrent metastatic squamous cell carcinoma of the head and neck (RMHNSCC) are not well known. Previously, we have found that Combined positive score (CPS) ≥90 and albumin &amp;gt;3.5 respond well to ICI treatment in patients with RMHNSCC treated with ICI irrespective of addition of chemotherapy. In the present study, we investigated whether RMHNSCC with CPS ≥90 has a characteristic genomic mutational profile. Methods. CPS measurements were performed on a single tumor specimen at the time of diagnosis of RMHNSCC, as approved by Japanese health insurance. Tumor specimens were obtained from the primary tumor as much as possible, and sections that best reflected anti-tumor immunity were decided by a pathologist. We retrospectively reviewed the results obtained from comprehensive genomic profiling (CGP) testing of RMHNSCC cases with CPS ≥90 who were treated by ICI experienced at our institution. Results. There were 117 eligible RMHNSCC cases. The number of primary lesions were oral cavity in 28 cases (23.9%), nasopharynx in 10 cases (8.5%), oropharynx in 21 cases (17.9%), hypopharynx in 33 cases (28.2%), and others in 18 cases (15.4%). Of 117 patients, 28 patients (23.9%) had a CPS ≥90. Of the 28 cases, the number of primary lesions were oral cavity in 12 cases (42.9%), nasopharynx in 4 cases (14.3%), oropharynx in 0 cases (0%), hypopharynx in 8 cases (28.6%), and others in 3 cases (10.7%). When ICI was administered, CPS ≥90 had a statistically significantly better prognosis than CPS &amp;lt;90 for OS and PFS. Of the 28 cases with CPS ≥90, CGP test was performed in 6 cases. The primary lesions in the 6 cases consisted of 3 oral cavity, 2 nasopharynx, 1 hypopharynx, and 1 maxillary sinus. All three oral primary cases had co-mutations in the TERT promoter and HRAS. Two of the nasopharyngeal primary cases had mutations in JAK3 and STAT, respectively. One of the hypopharyngeal primary cases had mutations in FGFR3. Conclusion. RMHNSCC with CPS ≥90 had unique mutations that could account the enhanced PD-L1 expression, such as TERT/HRAS co-mutation, JAK-STAT pathway mutation, and FGFR pathway mutation. The above findings may be useful for predicting the efficacy of ICI for RMHNSCC. Citation Format: Yuki Saito, Kage Hidenori, Kenya Kobayashi, Osamu Fukuoka, Koji Yamamura, Aya Shinozaki-Ushiku, Katsutoshi Oda, Kenji Kondo. Comprehensive genomic profiling of recurrent or metastatic head and neck cancer presenting with combined positive score 90 or more [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 3852.

Multi-omics Analysis Reveals Immune Features Associated with Immunotherapy Benefit in Patients with Squamous Cell Lung Cancer from Phase III Lung-MAP S1400I Trial.

Identifying molecular and immune features to guide immune checkpoint inhibitor (ICI)-based regimens remains an unmet clinical need. Tissue and longitudinal blood specimens from phase III trial S1400I in patients with metastatic squamous non-small cell carcinoma (SqNSCLC) treated with nivolumab monotherapy (nivo) or nivolumab plus ipilimumab (nivo+ipi) were subjected to multi-omics analyses including multiplex immunofluorescence (mIF), nCounter PanCancer Immune Profiling Panel, whole-exome sequencing, and Olink. Higher immune scores from immune gene expression profiling or immune cell infiltration by mIF were associated with response to ICIs and improved survival, except regulatory T cells, which were associated with worse overall survival (OS) for patients receiving nivo+ipi. Immune cell density and closer proximity of CD8+GZB+ T cells to malignant cells were associated with superior progression-free survival and OS. The cold immune landscape of NSCLC was associated with a higher level of chromosomal copy-number variation (CNV) burden. Patients with LRP1B-mutant tumors had a shorter survival than patients with LRP1B-wild-type tumors. Olink assays revealed soluble proteins such as LAMP3 increased in responders while IL6 and CXCL13 increased in nonresponders. Upregulation of serum CXCL13, MMP12, CSF-1, and IL8 were associated with worse survival before radiologic progression. The frequency, distribution, and clustering of immune cells relative to malignant ones can impact ICI efficacy in patients with SqNSCLC. High CNV burden may contribute to the cold immune microenvironment. Soluble inflammation/immune-related proteins in the blood have the potential to monitor therapeutic benefit from ICI treatment in patients with SqNSCLC.

Clinical characteristics of liver injury induced by immune checkpoint inhibitors in patients with advanced biliary tract carcinoma.

Immune-related liver injuries are closely associated with the liver's fundamental state. Patients with advanced biliary tract carcinoma (BTC) have poor liver function. We evaluated the clinical data of immune-related liver injury in patients with advanced BTC and gastric cancer (GC) during immune checkpoint inhibitor (ICI) treatment between February 2019 and July 2022 at Peking University First Hospital. Twenty-five patients with advanced BTC were identified. Fifteen patients (60%) experienced immune-related liver injury during ICI treatment. We also evaluated the clinical status of patients with GC in another group receiving immunotherapy. The results demonstrated that the incidence of immune-related liver injury was higher in patients with BTC than in GC cancer (p=0.040). Multivariate analysis suggested that the type of malignant tumor and baseline liver function status were high-risk factors for grade 2 and higher immune-related liver injuries. Two patients were diagnosed with immune-related cholangitis. Both biliary enzymes can be decreased to a certain degree by corticosteroid and ursodeoxycholic acid (UDCA) therapy but are difficult to reduce to normal levels. Liver function normalized, and symptoms improved after local treatment for cholestasis (stent implantation or PTBD). We observed a higher incidence of immune-related liver injury after ICI treatment in patients with advanced BTC. Effect of baseline liver function on the incidence of liver injury associated with immunotherapy. Interventional therapy provides rapid relief from cholestasis and is an indispensable and effective approach to the treatment of immune-related cholangitis.

CD47 polymorphism for predicting nivolumab benefit in patients with advanced non‑small‑cell lung cancer.

Immune checkpoint inhibitors (ICIs), such as nivolumab, play an essential role in non-small-cell lung cancer (NSCLC) treatment. Programmed death ligand-1 has been used as a predictive biomarker for the efficacy of ICI treatment in patients with NSCLC; however, its predictive value is considered insufficient. Therefore, there is an urgent need for better predictive biomarkers. The present study focused on the CD47 molecule, which is associated with macrophages and tumor immunity. The study aimed to investigate the association between CD47 single nucleotide polymorphism (SNP) and the therapeutic effect of nivolumab in patients with NSCLC. The CD47 SNP genotypes and clinical outcomes were retrospectively analyzed in 164 patients with NSCLC treated with nivolumab at Kyoto University Hospital (Kyoto, Japan). Patients with the G/G genotype of the CD47 SNP rs3804639 had significantly longer progression-free survival than those with the G/T or T/T genotypes [2.6 months vs. 2.1 months, hazard ratio (HR), 0.70; P=0.026]. Moreover, the G/G genotype of the CD47 SNP rs3804639 was associated with a significantly longer median overall survival than the G/T or T/T genotypes of the CD47 SNP rs3804639 (24.8 months vs. 12.0 months, HR, 0.64; P=0.021). In conclusion, CD47 polymorphism may be a novel predictive biomarker of nivolumab efficacy in patients with advanced NSCLC.

Abstract 6424: Immune characteristics and anti-PD-1-induced reinvigoration capacity of tumor-infiltrating lymphocytes in ovarian clear cell carcinoma relative to high-grade serous ovarian carcinoma

Abstract Recent clinical trials have demonstrated the potential efficacy of immune checkpoint inhibitors (ICIs) for ovarian clear cell carcinoma (OCCC). However, little is known about the immune characteristics of OCCC. In this study, we aimed to investigate the distinct immune characteristics of tumor-infiltrating lymphocytes (TILs) in OCCC to high-grade serous ovarian carcinoma (HGSOC). We isolated peripheral blood mononuclear cells (PBMCs) and TILs from patients with epithelial ovarian cancer. The expression of immune checkpoint receptors and T-cell transcription factors of TILs in OCCC (n=26) and HGSOC patients (n=44) were accessed using flow cytometry. TILs were ex vivo stimulated with anti-CD3 in the presence of anti-PD-1 and/or anti-CTLA-4, and their proliferation was assessed to predict response to ICIs. CD8 TILs and tumor-infiltrating regulatory T cells (Tregs) exhibited higher expression of immune checkpoint receptors, including PD-1, CTLA-4, and 4-1BB, compared to PBMCs. Tregs were more infiltrated in advanced/recurrent stage than early stage OCCC. However, immune characteristics of CD8 TILs and Tregs were not significantly different regardless of stage. When we compared the characteristics of TILs in OCCC (n=26) with those in HGSOC (n=44), the expression of PD-1 on CD8 TILs was significantly lower in OCCC than in HGSOC. The frequencies of PD-1highCD8 TILs and PD-1+TOX+CD8 TILs were also lower in OCCC than HGSOC. In ex vivo assay (n=19), 9 cases responded to anti-PD-1 in terms of enhanced proliferation capacity of CD8 TILs. In addition, when anti-CTLA-4 was added to anti-PD-1, an additional increase in proliferation of CD8 TILs was observed in patients who responded to anti-PD-1. Responders to anti-PD-1 had significantly lower frequencies of effector Tregs in the TILs than non-responders. Overall, CD8 TIL in OCCC was found to be less exhausted than HGSOC in terms of PD-1 and TOX expressions. Tumor-infiltrating Tregs affected on reinvigoration ability of CD8 TILs upon ICIs treatment in OCCC. This study provides the rationale and evidence for establishing the optimal strategies for ICIs treatment in patients with OCCC. Citation Format: Junsik Park, Yong Jae Lee, Jung Chul Kim, Jung-Yun Lee. Immune characteristics and anti-PD-1-induced reinvigoration capacity of tumor-infiltrating lymphocytes in ovarian clear cell carcinoma relative to high-grade serous ovarian carcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6424.

An enhanced genetic mutation-based model for predicting the efficacy of immune checkpoint inhibitors in patients with melanoma.

Programmed death ligand 1 (PD-L1) and tumor mutation burden (TMB) have been developed as biomarkers for the treatment of immune checkpoint inhibitors (ICIs). However, some patients who are TMB-high or PD-L1-high remained resistant to ICIs therapy. Therefore, a more clinically applicable and effective model for predicting the efficacy of ICIs is urgently needed. In this study, genomic data for 466 patients with melanoma treated with ICIs from seven independent cohorts were collected and used as training and validation cohorts (training cohort n = 300, validation cohort1 n = 61, validation cohort2 n = 105). Ten machine learning classifiers, including Random Forest classifier, Stochastic Gradient Descent (SGD) classifier and Linear Support Vector Classifier (SVC), were subsequently evaluated. The Linear SVC with a 186-gene mutation-based set was screened to construct the durable clinical benefit (DCB) model. Patients predicted to have DCB (pDCB) were associated with a better response to the treatment of ICIs in the validation cohort1 (AUC=0.838) and cohort2 (AUC=0.993). Compared with TMB and other reported genetic mutation-based signatures, the DCB model showed greater predictive power. Furthermore, we explored the genomic features in determining the benefits of ICIs treatment and found that patients with pDCB were associated with higher tumor immunogenicity. The DCB model constructed in this study can effectively predict the efficacy of ICIs treatment in patients with melanoma, which will be helpful for clinical decision-making.

Immune checkpoint inhibitors for RET fusion non-small cell lung cancer: hopes and challenges.

Immune ch eckpoint inhibitors (ICIs) represent a milestone in advanced nonsmall cell lung cancer (NSCLC). Nevertheless, NSCLC with known oncogenic drivers has been overlooked in most studies evaluating anti-programmed death-1/programmed death ligand 1. Rearranged during transfection proto-oncogene (RET) gene fusion was identified in 1-2% of NSCLC patients. More recently, two selective RET inhibitors, selpercatinib and pralsetinib, demonstrated higher efficacy and good tolerability. In contrast, the activity of ICIs in RET fusion NSCLC has not been well characterized. Here, we analyzed the clinical data of ICIs and discussed the suitable time to introduce ICIs in RET fusion NSCLC. Finally, we put forward future strategies to adequately maximize the efficacy of ICIs treatment in patients with RET fusion NSCLC in the upcoming era of combination immunotherapies.

Abstract 5098: Genetic and immunologic characteristics of biliary tract cancer patients with LRP1B mutation

Abstract Background: Although the initial clinical results of immune checkpoint inhibitors (ICI) have been obtained in biliary tract cancer (BTC), and previous researches explored potential biomarkers for predicting response to ICI in BTC, and gene LRP1B was found as one of predictive biomarkers. Here we evaluated the mutation information of LRP1B in Chinese patients with BTC, and analyzed the potential explanation for more benefit from ICI treatment in patients with LRP1B mutation. Methods: The formalin-fixed paraffin-embedded specimens of 1324 cancer patients who have underwent next-generation sequencing (NGS) from 2016 to 2021, were included in this study. NGS was performed to detect gene mutation, and tumor mutational burden (TMB) measured by a 733 gene panel. PD-L1 expression detected by using Dako PD-L1 IHC 22C3 pharmDx. Result: The NGS results revealed that 12.76% (169/1324) patients with BTC have LRP1B mutation. Among these 1324 patients, 931 (patients with or without LRP1B mutations were 129 and 802, respectively) patients were available for analysis of TMB level, 820 ((patients with or without LRP1B mutations were 114 and 706, respectively)) patients for analysis of PD-L1 expression, and 1163 (patients with or without LRP1B mutations were 172 and 991, respectively) patients for analysis of MSI-H. TMB level and PD-L1 expression level were compared between groups with and without LRP1B mutation, and results showed that both these two biomarkers were higher in group with LRP1B mutation than without LRP1B mutation, especially TMB level was significantly higher (p&amp;lt;0.001).Further analysis revealed that the median TMB level, proportion of strong positive PD-L1 expression, and proportion of MSI-H were all higher in group of LRP1B mutation than wild type. Conclusion:These results suggest that LRP1B can be considered as one of effective biomarkers for ICI treatment in BTC, the underly mechanism may be related to the high TMB level. Citation Format: Weiwei Chen, Hushan Zhang, Hongmin Dong, Gang Wang, Xiaokai Li, Wanghua Chen, Guodong Li, Saixi Bai, Juan Chen, Wenling Wang. Genetic and immunologic characteristics of biliary tract cancer patients with LRP1B mutation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5098.

Long-term toxicities with immune checkpoint inhibitor (ICI) in melanoma patients.

e21549 Background: The incorporation of ICI into the treatment of melanoma has greatly improved patient outcomes, but this benefit has come at the cost of exposing patients to immune-related adverse events (irAEs). A wide spectrum of irAE types has been described, and severity is known to vary from minor to life-threatening; however, the literature to date on the chronicity of irAEs is limited. Objectives: To characterize the long-term and permanent irAEs associated with ICI treatment in patients with melanoma, the treatment of irAEs and the association with survival outcomes. Methods: We performed a retrospective chart review of 161 adult patients with melanoma treated with at least one cycle of ICI regimen in the adjuvant or metastatic setting: 129 patients received PD-1 inhibitor monotherapy and 32 received dual immunotherapy. Patients were grouped by duration of irAE: permanent (no complete resolution), long-term (resolution over a period ≥6 months), transient (resolution over a period &lt; 6 months), or no irAEs. Overall survival was evaluated for those patients that were treated in the metastatic setting with PD1 inhibitor monotherapy. Results: Thirty-eight patients were treated in the adjuvant setting and 123 patients were treated in the metastatic setting. A total of 279 irAEs were reported in the whole patient population. Sixty-six (41.0%) patients developed permanent irAEs, 15 (9.3%) experienced long-term irAEs as their longest-lasting toxicity, 34 (21.1%) developed transient irAEs only, and 46 (28.6%) experienced no irAEs. Permanent irAEs occurred in 21 (65.6%) patients treated with dual immunotherapy and in 45 (34.9%) patients treated with monotherapy. The majority of permanent irAEs were endocrine-related (35.5%) or skin-related (32.7%). Grade ≥3 permanent irAEs occurred in 20 (12.4%) patients and included toxicities such as adrenal insufficiency, myocarditis, and myelitis. Fifty-three (32.9%) patients were still on treatment for long-term or permanent irAEs 6 months or more following completion of ICI therapy, including 23 patients on thyroid replacement and 22 on oral steroids. ICI treatment was temporarily interrupted for 63 (22.6%) irAEs and permanently discontinued due to irAE in 38 (13.6%) patients. Subgroup analysis of patients who received single-agent ICI in the first-line palliative setting reveals that those with longer-duration irAEs had a significantly longer median overall survival. Conclusions: Despite the significant benefits, treatment with ICIs in melanoma is associated with a wide range of toxicities that can be permanent and may have long-lasting impacts on patients. The risk of long-term toxicity should therefore be discussed when obtaining consent for treatment. As these treatments are being used more commonly in the adjuvant setting, the impact of survivorship and the long-term management of these toxicities is increasingly important.

Clinical outcomes of immune checkpoint inhibitor (ICI) therapy among Veterans Affairs patients with colorectal cancer and discordant dMMR/MSI-H status.

3534 Background: Clinical trials have demonstrated improvements in survival with immune checkpoint inhibitors (ICIs) for advanced colorectal cancer patients with MSI-H/dMMR detected using PCR-based assays (PCR) or immunohistochemistry (IHC), respectively. MSI-H can also be assessed by next-generation sequencing (NGS). Evaluation of real-world outcomes among MSI-H patients by NGS treated with ICIs are warranted, particularly when results are discordant between these tests. Methods: The VA National Precision Oncology Program Database was accessed to select veterans with colorectal cancer and an MSI-H biomarker by NGS. Baseline patient variables, disease characteristics, and duration of ICI treatment were obtained from the VA’s Corporate Data Warehouse. Concordance between NGS and IHC or PCR testing was computed, and the response rate and duration of ICI treatment in patients with discordant test results were recorded from chart review. Results: Among 1,276 colorectal cancer patients, 71 (5.6%) were found to have MSI-H by NGS. Of these, 22 (30.1%) received ICI. Among 49 patients who did not receive ICI, 36 had stage I-III disease, 5 had limited performance status, 5 were actively being treated with chemotherapy and 3 had completely resected stage IV disease. Of the 71 patients, 29 had dMMR IHC testing, 8 had MSI-H PCR testing, 1 had both IHC and PCR testing, and 34 patients had only NGS testing. No PCR tests were discordant with NGS but 8 of 29 IHC tests were discordant. Among these 8 patients with discordant IHC MMR and MSI-H by NGS, 5 received pembrolizumab. There were 3 partial responses, 1 stable disease and 1 progressive disease. Durable responses were seen with 3 of 5 patients remaining on therapy without progression at the time of this analysis at a median follow up of 8.5 months. Conclusions: In a cohort of NGS MSI-H colorectal cancer patients, there was a high rate of discordant IHC results. Clinical benefit is seen in patients treated with ICI with discordant testing results, suggesting that NGS testing identifies patients with false negative dMMR IHC testing in the real-world clinical setting.

Disease exacerbation is common in inflammatory bowel disease patients treated with immune checkpoint inhibitors for malignancy.

BACKGROUNDColitis is a known potential toxicity of immune checkpoint inhibitors (ICIs). Studies evaluating the risk of disease exacerbation following ICI treatment in patients with pre-existing inflammatory bowel disease (IBD) are limited.AIMTo assess the clinical characteristics of IBD patients treated with ICIs and determine prevalence of subsequent IBD exacerbations.METHODSWe conducted a retrospective cohort study of all patients in the Stanford Research Repository database with pre-existing IBD who were exposed to ICIs.RESULTSThe prevalence of IBD exacerbation following ICI was 36.8% amongst 19 patients meeting inclusion criteria. Patients with exacerbations had more gastrointestinal-related hospitalizations (4 of 7) than patients without exacerbations (0 of 12; P = 0.0090).CONCLUSIONThe prevalence of IBD exacerbations following ICI was higher than reported rates of ICI-induced colitis and diarrhea in the general population and was associated with hospitalization.

MUC16 Alternation is a Potential Biomarker for Prognosis in Patients with Gastric Cancer Receiving Immunotherapy

Background: Immune checkpoint inhibitors (ICIs) have recently attracted much attention for the treatment of gastric cancer. However, the response rate of patients without selective treatment is low. Therefore, screening for the predictors of ICIs efficacy prior to treatment is the key to providing the ideal treatment. Cell surface associated Mucin 16 (MUC16) is significantly related to the occurrence and progress of various malignant tumors. Therefore, the relationship between MUC16 and the efficacy of ICIs, as well as its potential mechanism, require further study. Methods: We began by collecting a gastric cancer data set from a public database, and the immunotherapy cohort that we chose was selected from published studies. We analyzed the influence of MUC16 mutation on clinical prognosis, gene mutation frequency, and the immune microenvironment. Gene Set Enrichment Analysis (GSEA) was used to evaluate significant up-regulation and down-regulation in response pathways. We used the drug data from the Genomics of Drug Sensitivity in Cancer (GDSC) database to analyze the influence of MUC16 mutation on drug sensitivity. Results: Univariate and multivariate Cox regression analysis and logistic regression analysis show that the presence of MUC16 mutation can result in a better prognosis for patients and high efficacy of immunotherapy, and as such can be used as an independent factor to predict the efficacy of ICIs. The analysis results of immunogenicity and the immune microenvironment showed that MUC16 mutation causes a higher tumor mutation load and new antigen load, higher levels of activated immune cells, and significantly up-regulated immune response-related pathways. Conclusions: MUC16 mutation can be used as an independent predictor of the curative effect of ICIs treatment in patients with gastric cancer, and it is related to greater immunotherapy efficacy, higher immunogenicity, and a significantly improved immune microenvironment.