Immune Checkpoint Inhibitor Therapy Research Articles

Evaluation of blood MSI burden dynamics to trace immune checkpoint inhibitor therapy efficacy through the course of treatment.

Analysis of serial liquid biopsy (LB) samples has been found to be a promising approach for the monitoring of tumor dynamics in the course of therapy for patients with colorectal cancer (CRC). Currently, somatic mutations are used for tracing the dynamics of the tumor via LB. However, the analysis of the dynamic changes in the molecular signatures such as microsatellite instability (MSI) is not currently used. We hypothesized that changes in blood MSI burden (bMSI) could be registered using serial LB sampling in the course of immune checkpoint inhibitors (ICI), and that its changes could potentially correlate with treatment outcomes. We report the preliminary findings of the observational trial launched to study (NCT06414304) the dynamics of bMSI in 9 MSI-positive CRC patients receiving ICI. NGS-based MSI testing was performed on both pre-treatment FFPE and serial LB samples. For patients who had detectable bMSI burden in any of the LB samples (n = 8, 89%), median bMSI was 1.4% (range, 0.01-40%). Among patients with detectable MSI in available FFPE samples, median MSI burden was 29.3% (range, 10-40%). bMSI detected in baseline LB and FFPE samples were positively correlated (Pearson's R 0.47). Maximal variant allele frequencies of driver mutations observed in LB were also positively correlated with bMSI burden (Pearson's R 0.7). Patients who had clinical benefit had undetectable bMSI burden at follow-up. Our results provide the rationale for further validation of bMSI as a predictive biomarker of ICI in MSI-positive patients.

Dual PD-L1/SOX10 Immunohistochemistry Combined With Digital Imaging Enhances Stratification Accuracy of Patients With Metastatic Melanoma.

Immune checkpoint inhibitor therapy has demonstrated an overall survival benefit in patients with advanced melanoma. Though the significance of programmed death-ligand 1 (PD-L1) expression on melanoma cells as a predictive biomarker of response remains inconclusive, some reports indicate that a PD-L1 expression of <1% of tumor cells may be associated with better outcomes with dual immunotherapy. Adequate patient selection for combination therapy is critical given the higher frequency of adverse effects compared with monotherapy. Immunohistochemical (IHC) PD-L1 interpretation in tumor cells is challenging when inflammatory cells are present and cutoffs are low. We studied 36 metastatic melanoma biopsies from Immune checkpoint inhibitor-naive patients, previously stained and scored for PD-L1 IHC using the tumor proportion score (TPS). Cases were classified into 3 groups: <1%, 1% to 5%, and >5%. After de-coverslipping, SRY-related HMG-box-10 (SOX10) IHC was performed on PD-L1 IHC slides with a red chromogen, and subsequently scanned and scored by ≥2 dermatopathologists. This assessment determined that 25% of cases (9/36) had a TPS ≥ 1%, in contrast to the single IHC assay (63.8%). The majority of the 1-5% group (11/13, 84.6%) underwent a change of category to <1% TPS. In the >5% group, 60% of cases (6/10) were downgraded to <1% and 1% to 5% (4 and 2 cases, respectively). Our study suggests that PD-L1 IHC evaluation could benefit from dual PD-L1/SOX10 IHC. Dual IHC is expected to decrease the interference caused by PD-L1 expression on inflammatory cells, and digital imaging proves useful for the preservation and analysis of stains. Refining PD-L1 evaluation in metastatic melanoma may improve clinical decisions between single and combination immunotherapy, with potentially profound consequences in response and quality of life.

Prognostic risk score and index including the platelet-to-lymphocyte ratio and lactate dehydrogenase in patients with metastatic or unresectable urothelial carcinoma treated with immune checkpoint inhibitors.

Avelumab and pembrolizumab are administered after platinum-based chemotherapy for the treatment of metastatic urothelial carcinoma. We explored the prognostic factors and risk scores for predicting the outcomes of metastatic or unresectable urothelial carcinoma at the start of treatment with immune checkpoint inhibitors. This retrospective study included patients with metastatic or unresectable urothelial carcinoma treated with avelumab or pembrolizumab after platinum-based chemotherapy between January 2017 and December 2022. Prognostic factors, including patient and tumor characteristics and blood data at the initiation of immune checkpoint inhibitor therapy, were examined. This study included 36 and 207 patients treated with avelumab and pembrolizumab, respectively, for metastatic or unresectable urothelial carcinoma. Eastern Cooperative Oncology Group performance status, presence of visceral metastases, platelet-to-lymphocyte ratio and lactate dehydrogenase levels were independent prognostic factors for predicting overall survival. The median overall survival of patients in the risk-score model was 58.5months (score zero), 27.9months (one), 13.1months (two) and 3.9months (three or higher). The C-index for overall survival was 0.718 for the newly developed risk score compared with 0.679 for the Bellmunt score and 0.703 for the Bellmunt-C-reactive protein score. Additionally, the C-index for overall survival using the immune prognostic index derived from lactate dehydrogenase and the platelet-to-lymphocyte ratio was 0.646 compared with 0.615 for the Lung Immune Prognostic Index. A risk score that includes the platelet-to-lymphocyte ratio and lactate dehydrogenase may serve as a useful model for predicting prognosis following the initiation of immune checkpoint inhibitors in patients with metastatic or unresectable urothelial carcinoma.

7967 Ruxolitinib Prevents Immune-Checkpoint Inhibitor-Related Diabetes Mellitus Via Inhibition Of Pathogenic IL-21 And IFNγ-Producing CD4+ T Cells

Abstract Disclosure: N.L. Huang: None. J. Ortega: None. S.J. Wang: None. L.N. Scott: None. K. Kimbrell: None. E. McCarthy: None. J. Olay: None. J.N. Nguyen: None. K. Kim: None. J. Lee: None. M.G. Lechner: None. The use of immune checkpoint inhibitor (ICI) therapy has revolutionized the treatment landscape for many advanced cancers by leveraging immune activation through the blockade of checkpoint proteins, including programmed death protein-1 (PD-1). Unfortunately, autoimmune attack of healthy tissue can occur in up to 60% of patients. ICI-induced Type 1 diabetes mellitus (ICI-T1DM) is a rare but life-threatening adverse event during ICI therapy that leads to rapid destruction of pancreatic islets, hyperglycemia, and lifetime dependence on insulin. While cytotoxic CD8+ T cells are recognized as important players in ICI-T1DM, the role for CD4+ helper T cells in disease pathogenesis is less well understood. Using a mouse model of ICI-autoimmunity, in which male and female NOD mice treated with anti-PD-1 (10mg/kg/day, i.p., twice weekly) develop multi-organ autoimmune infiltrates including insulitis and DM, we identified interleukin-21 (IL-21) and interferon gamma (IFNγ) CD4+ T cells as key contributors to ICI-T1DM. Antibody depletion of CD4+ T cells in NOD mice significantly delayed the onset of ICI-T1DM. Immunophenotyping of pancreatic islet infiltrates in ICI-treated mice revealed increased IL-21+ IFNγ+ CD4+ T follicular helper (Tfh; ICOS+ PD1+ CXCR5+) and T peripheral helper (Tph; ICOS+PD1+ CXCR5- CXCR6+) cells. In vitro, IL-21 increased effector CD8+ T cell function and IFNγ promoted production of T cell-attracting chemokines CXCL9, CXCL10, and CXCL16 by macrophages. Given the potential role for IL-21 and IFNγ to amplify ICI-DM progression, we sought to target these signaling pathways as potential interventions. Genetic inhibition of IL-21 or IFNγ signaling in NOD mice reduced insulitis and DM in anti-PD-1 treated mice. Considering that IL-21 and IFNγ act through JAK/STAT signaling in immune cells, we proposed to block this pathway to prevent ICI-DM using ruxolitinib, a clinically available JAK1/2 inhibitor. Indeed, ruxolitinib blocked STAT3 and STAT1 phosphorylation in mouse splenocytes in response to IL-21 or IFNγ, respectively, and completely protected ICI-treated NOD mice from DM. Finally, in a syngeneic tumor model, use of ruxolitinib after initiation of anti-PD-1 therapy did not abrogate ICI anti-tumor effects. Taken together, these data suggest that IL-21 and IFNγ producing CD4+ T cells are important drivers of ICI-T1DM, and that the use of JAK inhibitors may be a promising clinical intervention to reduce ICI-T1DM toxicities in patients. Presentation: 6/2/2024

12204 Role Of [18F]FDG-PET/CT In Detection Of Immunotherapy-induced Hypophysitis - A Case-control Study

Abstract Disclosure: A. Fischer: None. J.M. Martinez Gomez: None. J. Mangana: None. R. Dummer: None. Z. Erlic: None. S. Nölting: None. F. Beuschlein: None. A. Maurer: None. M. Messerli: None. M.W. Huellner: None. S. Skawran: None. Adverse events related to immune-checkpoint inhibitor (ICI) therapy frequently affect endocrine organs. Depending on the type of ICI therapy, 0.5% to 10% of patients develop hypophysitis. Diagnosis relies on unspecific clinical symptoms and low serum cortisol level. On MRI, the diagnosis of ICI-induced hypophysitis is supported by enlargement of the pituitary gland and its stalk. However, pituitary MRI is negative in up to 2/3 of patients with hypophysitis on anti-PD-1 monotherapy. A delayed diagnosis increases the risk for life-threatening adrenal crisis. Consequently, there is a need for diagnostic tools that facilitate the early detection of ICI-induced hypophysitis. In this retrospective, single-center case-control-study, we investigated the diagnostic efficacy of [[1]8F]FDG positron emission tomography/computed tomography (FDG-PET/CT) in detecting ICI-induced hypophysitis. Fourteen patients with metastatic melanoma and ICI-induced hypophysitis were compared to a control group of 14 metastatic melanoma patients undergoing ICI treatment without evidence of hypophysitis, matched for age and sex. FDG-PET/CT scans were acquired as part of routine clinical care between 79 days before to 8 days after hypophysitis diagnosis (mean 26+/-29 days before diagnosis) in the case group. In the control group, FDG-PET/CT scans were obtained at a mean of 78+/-31 days after initiating ICI therapy. To mitigate inter-individual differences in standardized uptake value (SUV), the ratio of maximum SUV of the pituitary gland to the mean SUV of the blood pool (SUV-ratio pituitary/bloodpool) was calculated. Hypophysitis was diagnosed at a median of 83 (range: 65 - 98) days after the first ICI treatment; 9/14 (64.3%) patients received ipilimumab/nivolumab. Isolated cortisol deficiency was observed in 6/14 patients (42.9%), while 7/14 (50.0%) patients also displayed secondary hypothyroidism. Visual assessment of the distribution of the SUV-ratio pituitary/bloodpool demonstrated a positive correlation with decreasing proximity to the time of diagnosis. To evaluate diagnostic performance, only patients within 50 days before and 8 days after diagnosis (12/14) were included. The SUV-ratio pituitary/bloodpool was significantly higher in the case group compared to the control group (mean 3.57+/-3.24 vs. 1.69+/-0.41 respectively; p = 0.034). By optimizing the Youden index through area under the receiver operating characteristics curve (AUC) analysis, a sensitivity of 72.7% and a specificity of 90.9% were achieved at a threshold of 2.41 for the SUV-ratio pituitary/bloodpool (AUC = 0.769). In conclusion, our findings indicate that in patients undergoing ICI treatment for metastatic melanoma, an pituitary SUV-ratio pituitary/bloodpool in FDG-PET/CT of approximately 2.5 might indicate impending ICI-induced hypophysitis and should trigger close clinical monitoring. Presentation: 6/3/2024

8812 Incidence And Clinical Experience Of Immune Checkpoint Inhibitors-Induced Endocrine Side Effects Among Filipino Cancer Patients: A Single-Center Retrospective Study

Abstract Disclosure: N.B. Luna: None. E. Mendoza: None. S.A. Kho: None. Incidence And Clinical Experience Of Immune Checkpoint Inhibitors-Induced Endocrine Side Effects Among Filipino Cancer Patients: A Single-Center, Retrospective Study Immune checkpoint inhibitors (ICIs) serve as immunomodulatory antibodies, which enhance the immune system and substantially improve the prognosis for patients with advanced malignancies [1]. Referral to endocrinology have been increasing because ICIs were associated with endocrine-related adverse effects including hypothyroidism, hyperthyroidism, diabetes, hypophysitis and adrenalitis. Hence, the study aimed to retrospectively determine the local prevalence and profile of Filipino patients who developed endocrinopathies during ICI therapy at the University of Santo Tomas Hospital (USTH), Manila, Philippines from 2013-2019. A single-center retrospective study of ICI-treated cancer patients with serial biochemical and/or radiologic monitoring of endocrine adverse effects was done upon approval by the Research Ethics Committee. A total of 27 subjects were included with a median age of 60 years and male predominance. Pembrolizumab consisted 93% of the ICIs given. The incidence of thyroid dysfunction was 36% (18% overt hypothyroidism, 9% subclinical hypothyroidism, and 9% subclinical hyperthyroidism). The median time at risk for development of overt hypothyroidism is 4 weeks with median TSH level of 9.05 uIU/mL from baseline level of 3.77 uIU/mL. All patients who had baseline hypothyroidism worsened with increase from baseline levothyroxine dose by 50 to 230% in order to achieve euthyroidism (p 0.037). Serial monitoring was done every 2 weeks until euthyroidism. ICIs were temporarily put on hold in 75%. Diabetes (p 0.05), renal carcinoma (p 0.001) and dose of 200mg (p 0.42) were associated to developing overt hypothyroidism. Checking of glycemic levels was not routine among non-diabetic patients. Fifteen percent of diabetic patients had worsening of control (median HbA1c 8.5% [8-9] and 23% were newly diagnosed pre-diabetes (median fasting glucose 114mg/dL [104-120]). With the available imaging results, there were no abnormal adrenal metabolic uptake on PET scan and no evidence of hypophysitis in pituitary MRI. In conclusion, overt hypothyroidism is a common occurrence during ICI therapy (18%). Worsening occurred among all patients with hypothyroidism at baseline. New-onset pre-diabetes and worsening of glycemic control were seen in 15 and 23%, respectively. Serial clinical and biochemical monitoring is important and referral to endocrinology should be made if deemed necessary. [1] L Agrawal, A Bacal, S Jain, V Singh, N Emanuele, Ma Emanuele &amp; F Meah (2020) Immune checkpoint inhibitors and endocrine side effects, a narrative review, Postgraduate Medicine, 132:2, 206-214, DOI: 10.1080/00325481. 2019. 1709344 Presentation: 6/1/2024

12265 Isolated Adrenocorticotropic Hormone Deficiency In The Setting Of Anti-PD1 Immunotherapy

Abstract Disclosure: J. Poncelet: None. Q. Wang: None. A.J. Montero: Advisory Board Member; Self; AstraZeneca, Gilead. Other; Self; Medical Advisor for Paragon Infusion Services. L. Tranchito: None. Isolated Adrenocorticotropic Hormone Deficiency in the Setting of Anti-PD1 Immunotherapy Introduction: Immune checkpoint inhibitors have been associated with endocrine immune-related adverse events, such as secondary adrenal insufficiency with isolated ACTH deficiency in rare instances. Case Presentations: We present two different cases of isolated ACTH deficiency (IAD) while on anti-PD1 therapy with pembrolizumab. Patient A is a 66-year-old woman with history of tobacco use, hypertension, and COPD diagnosed with stage IV lung adenocarcinoma. After completing 15 cycles of pembrolizumab, she reported symptoms of fatigue, weakness, lightheadedness, and was subsequently admitted to the hospital for symptomatic hyponatremia. Lab workup revealed a morning cortisol level of 0.6 ug/dL (n2.5-20 ug/dL) and ACTH &amp;lt;1.5 pg/mL (n7.2-63.3 pg/mL), both of which had previously been normal. Her TSH was mildly elevated with a normal free T4. Her FSH, LH, prolactin, and IGF levels were normal as was MRI of the pituitary. She therefore was diagnosed with IAD and started physiologic steroid replacement therapy with hydrocortisone with subsequent symptomatic improvement and normalization of her serum sodium. Patient B is a 60-year-old woman with a history of osteoporosis, aortic stenosis, and stage II triple negative breast cancer treated with neoadjuvant chemotherapy and pembrolizumab. Two months after starting immunotherapy, she presented to her oncology office with symptoms of fatigue, poor appetite, body aches, and dizziness. Her labs revealed mild hyponatremia, cortisol of 0.9 ug/dL (n2.5-20 ug/dL) and ACTH &amp;lt;1.5 pg/mL (n7.2-63.3 pg/mL). TSH, LH, FSH, and prolactin levels were normal. She started physiologic steroid replacement therapy with hydrocortisone for IAD, which led to improvement in her symptoms. Both patients continue pembrolizumab. Conclusions: Immune-related adverse events affecting endocrine pathways have been reported with immune checkpoint inhibitors. There is no method to predict which patients may be affected, and no guidelines exist on when or how often to monitor hormone levels in these patients. Importantly, patients can continue immune checkpoint inhibitors despite IAD if controlled by hormone replacement, though ACTH recovery should not be expected[1]. Recognition of symptoms can prompt earlier evaluation for secondary adrenal insufficiency and provide greater benefit to patients. 1.Schneider BJ, Naidoo J, Santomasso BD, et al. Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update [published correction appears in J Clin Oncol. 2022 Jan 20;40(3):315]. J Clin Oncol. 2021;39(36):4073-4126. doi:10.1200/JCO.21.01440 Presentation: 6/1/2024

Thromboembolism during immune checkpoint inhibitor therapy: frequency and risk factors

BackgroundThromboembolism (TE) is a well-known complication during chemotherapy in cancer patients. However, the risk of TE associated with immune checkpoint inhibitors (ICIs) is unknown. This study was performed to investigate the incidence of TE and associated risk factors in patients treated with ICIs.MethodsWe conducted a retrospective chart survey of patients receiving at least one ICI at Shinshu University Hospital between September 2014 and October 2021. Age, sex, cancer type, body mass index, medical history, laboratory data at commencement of treatment, and medication data were obtained from electronic medical records. TE events (venous thromboembolism [VTE], arterial thromboembolism [ATE]) were identified after ICI initiation.ResultsThe study population consisted of 548 patients with a median age of 70.0 (19–89) years, 71.4% men, and a median follow-up of 15.1 months (range; 0.16–72.0 months). Nivolumab was the most commonly used ICI (45.8%), followed by pembrolizumab (23.9%), pembrolizumab plus anticancer drugs (7.8%), and nivolumab plus ipilimumab (5.1%). Thirty-eight cases of TE (6.9%) occurred (22 VTE, 16 ATE). Risk factors significantly associated with TE in multivariate logistic analysis were dyslipidemia (OR 2.44; 95% CI 1.17–5.09; p = 0.017), Khorana score ≥ 2 (HR 2.40; 95% CI 1.14–5.04; p = 0.021). Overall survival was not significantly different from patients without TE (p = 0.963).ConclusionThese results suggested that the frequency of TE is higher than expected and should be considered and monitored in patients treated with ICIs.

8581 Unusual Case of Multifactorial Hyperthyroidism

Abstract Disclosure: D.D. Bagar: None. E. Meyers: None. M. Correia: None. Background: Nivolumab is an immune checkpoint inhibitor that is used to treat specific types of cancer, including melanoma, by increasing the ability of the immune system to detect cancer through activating cytotoxic T-cells. The side effects of immune checkpoint inhibitors are mainly through the overactivation of the immune system that can affect many organs with autoimmune diseases, including endocrine glands, which could be severe and irreversible, like hypothyroidism or immune thyroiditis. The uniqueness of this case is the presence of multifactorial causes of hyperthyroidism; in addition, it is one of the few cases of immune checkpoint inhibitor induced positive TSI thyroiditis.Clinical Case: An 82-year-old male with a known history of atrial fibrillation on amiodarone presented to his dermatologist with a left forearm lesion. A shave biopsy showed melanoma, and he underwent wide local excision with negative sentinel lymph node biopsy. However, he had significant melanoma in situ present within 5 mm of the margin and was deemed not a candidate for further excision. Tumor board recommended close surveillance. He then received two cycles of pembrolizumab for one year, followed by nivolumab. During his treatment course, he had CT scans with iodinated contrast every 8-12 weeks for the clinical trial. At his clinic visit, routine thyroid function tests were significant for hyperthyroidism with a TSH &amp;lt;0.01 and free T4 of 6.07 (0.8-1.8). He was asymptomatic except for unintentional weight loss. He denied using any biotin supplements. His labs also showed positive thyroid stimulating immunoglobulin (TSI) of 1.10 (&amp;lt;=0.54 IU/L). A thyroid US with doppler showed two nodules less than 1.1 cm and no increased vascularity. Amiodarone was discontinued, and prednisone and methimazole were started. His free T4 has since normalized and both prednisone and methimazole are being tapered down. Conclusion: This case is a multifactorial cause of hyperthyroidism. He had been using amiodarone for atrial fibrillation, had multiple imaging studies with iodinated contrast, and was on immune checkpoint inhibitor therapy with a positive TSI. The uniqueness of this case is not only that combined factors can affect thyroid function but also that he developed a positive TSI, which indicates either Graves’ disease or immune-induced thyroiditis by nivolumab, which has been reported only in a few cases. Presentation: 6/3/2024

8581 Unusual Case Of Multifactorial Hyperthyroidism

Abstract Disclosure: D.D. Bagar: None. E. Meyers: None. M. Correia: None. Background: Nivolumab is an immune checkpoint inhibitor that is used to treat specific types of cancer, including melanoma, by increasing the ability of the immune system to detect cancer through activating cytotoxic T-cells. The side effects of immune checkpoint inhibitors are mainly through the overactivation of the immune system that can affect many organs with autoimmune diseases, including endocrine glands, which could be severe and irreversible, like hypothyroidism or immune thyroiditis. The uniqueness of this case is the presence of multifactorial causes of hyperthyroidism; in addition, it is one of the few cases of immune checkpoint inhibitor induced positive TSI thyroiditis.Clinical Case: An 82-year-old male with a known history of atrial fibrillation on amiodarone presented to his dermatologist with a left forearm lesion. A shave biopsy showed melanoma, and he underwent wide local excision with negative sentinel lymph node biopsy. However, he had significant melanoma in situ present within 5 mm of the margin and was deemed not a candidate for further excision. Tumor board recommended close surveillance. He then received two cycles of pembrolizumab for one year, followed by nivolumab. During his treatment course, he had CT scans with iodinated contrast every 8-12 weeks for the clinical trial. At his clinic visit, routine thyroid function tests were significant for hyperthyroidism with a TSH &amp;lt;0.01 and free T4 of 6.07 (0.8-1.8). He was asymptomatic except for unintentional weight loss. He denied using any biotin supplements. His labs also showed positive thyroid stimulating immunoglobulin (TSI) of 1.10 (&amp;lt;=0.54 IU/L). A thyroid US with doppler showed two nodules less than 1.1 cm and no increased vascularity. Amiodarone was discontinued, and prednisone and methimazole were started. His free T4 has since normalized and both prednisone and methimazole are being tapered down. Conclusion: This case is a multifactorial cause of hyperthyroidism. He had been using amiodarone for atrial fibrillation, had multiple imaging studies with iodinated contrast, and was on immune checkpoint inhibitor therapy with a positive TSI. The uniqueness of this case is not only that combined factors can affect thyroid function but also that he developed a positive TSI, which indicates either Graves’ disease or immune-induced thyroiditis by nivolumab, which has been reported only in a few cases. Presentation: 6/3/2024

12337 Nivolumab Induced Secondary Adrenal Insufficiency And Hypothyroidism In A Patient With Graves’ Disease: A Case Report

Abstract Disclosure: F. Sajid: None. J. Kaur: None. A. Zatsepina: None. M. Khan: None. C.A. Resta: None. Introduction: We present a case of a patient with Graves’ disease who developed concurrent secondary adrenal insufficiency (SAI) and primary hypothyroidism while undergoing treatment with nivolumab for non-small cell lung cancer (NSCLC). This case sheds light on the immune-related adverse events (irAEs) associated with immune checkpoint inhibitor (ICI) therapy. Case Presentation: A 63-year-old woman with a history of Graves’ disease and NSCLC undergoing neoadjuvant chemoimmunotherapy was admitted with hyponatremia. She was diagnosed with Graves’ disease a year before and was treated with methimazole (MMI). When she was diagnosed with Graves’ disease, her TSI was 1.64 IU/L (&amp;lt;0.55). Before starting nivolumab, TSH had normalized at 0.5 MCIU/mL on MMI therapy. She started nivolumab 3 months before admission. One month after starting nivolumab, her TSH was &amp;lt;0.01. By the time she was admitted, she had severe hypothyroidism and SAI with sodium 116 mmol/L (135-149), TSH 40.34 mIU/mL (0.39-4.08), free T4 &amp;lt;0.25 ng/dL (0.8-1.8), TSI 21.2 IU/L (0.00-0.55) Total Cortisol 0.4 ug/dL (6.7-27.6), AM Cortisol 0.6 ug/dL, ACTH &amp;lt;1.5 pg/mL (7.2-63.3), LH 75.5 IU/L (7.7-58.5), and FSH 179 IU/L (25.8-134.8). MMI was discontinued due to hypothyroidism. She was started on replacement therapy with levothyroxine and hydrocortisone. Subsequent sodium levels normalized. Discussion: Nivolumab has emerged as a promising immunotherapy for NSCLC. Our patient developed irAEs following nivolumab treatment. Notably, this case represents only the third documented case to our knowledge of both primary hypothyroidism and secondary adrenal insufficiency occurring post-nivolumab treatment. Workup for our patient revealed two irAE’s. She developed primary hypothyroidism and isolated ACTH deficiency with other pituitary function remaining normal. The pattern of thyroid profile over time was consistent with thyroiditis due to ICI therapy. TSI increased, ruling out remission from Graves’ disease. Even after discontinuing methimazole, she remained hypothyroid. Hence, in this case, ICI effectively acted as definitive therapy for her Graves’ disease. Conclusion: This case sheds light on the intricate interplay between nivolumab therapy, pre-existing autoimmune conditions such as Graves’ Disease, and the emergence of irAEs. This case underscores the importance of vigilant monitoring of serum sodium levels, and thyroid and pituitary function tests in patients undergoing immunotherapy. Presentation: 6/1/2024

Increased myositis and possible myocarditis in melanoma patients treated with immune checkpoint inhibitors in the COVID-19 era.

Immune checkpoint inhibitor (ICI)-mediated myocarditis results in significant morbidity and mortality. At our institution, we noted an increased incidence of ICI-mediated myocarditis cases, leading to further investigation in our database of advanced melanoma patients treated with ICI therapy. A single-center, retrospective cohort analysis of patients with advanced melanoma identified cases of ICI-mediated myocarditis and myositis. 366 patients with advanced melanoma received a dose of ICI from September 2014 to October 2019. Of these patients, there were 0 cases of ICI-mediated myocarditis (0%, 95% CI 0%-1.0%) and 2 cases of ICI-mediated myositis (0.55%, 95% CI 0.07%-1.96%). From November 2019 to December 2021, an additional 246 patients with advanced melanoma were identified. Of these patients, 10 (4.1%, 95% CI 1.97%-7.35%) developed ICI-mediated myocarditis and 10 developed ICI-mediated myositis. Our study suggests an increase in prevalence of ICI-mediated muscle damage including myositis and myocarditis in the COVID-19 era. Differentiation of these patients and further risk stratification may allow for development of guidelines for nuanced management of this serious complication.

8439 Targeting Interferon Gamma-Mediated CXCL16-CXCR6 Chemokine-Receptor Interactions As A Strategy To Prevent Immune Checkpoint Inhibitor Autoimmune Diabetes

Abstract Disclosure: S. Wang: None. N. Huang: None. J.G. Ortega: None. J. Lee: None. K. Kimbrell: None. J. Nguyen: None. J. Olay: None. E. McCarthy: None. E. Peluso: None. H. Chen: None. M.G. Lechner: None. Autoimmune diabetes mellitus is a rare but life-threatening side effect of immune checkpoint inhibitor (ICI) cancer therapy. Checkpoint inhibitors increase immune activation by blocking regulatory molecules on T cells, including programmed death protein (PD1). As a result of this heightened immune activation, patients can develop autoimmunity in healthy tissues, known as immune related adverse events (IRAEs). ICI-associated diabetes mellitus (ICI-T1DM) is an IRAE that results in autoimmune destruction of insulin-producing pancreatic beta-cells. Patients with ICI-T1DM require life-long insulin therapy and more than half present initially with diabetic ketoacidosis. Unfortunately, the mechanism of this IRAE is not fully understood. Anti-PD1 antibody treatment (10mg/kg/dose, twice weekly, i.p.) of male and female non-obese diabetic (NOD) mice leads to autoimmune infiltrates in multiple tissues, including accelerated insulitis and DM. Single cell RNA sequencing of islet infiltrating immune cells from ICI-treated mice previously showed a role for CD8+ T cells and cytokine interferon gamma (IFNγ) in the development of ICI-T1DM. Using CellChat to perform receptor-ligand interaction analysis of these data, we identified both CD8+ and CD4+ T cells as the primary source of IFNγ in immune infiltrates and islet myeloid cells as the primary target. Furthermore, CellChat analysis showed increased receptor-ligand interactions between T cell receptor CXCR6 and its chemokine CXCL16, as well as CXCR3 and chemokines CXCL9 and CXCL10. In vitro IFNγ stimulation of myeloid cells induced strong expression of CXCL16, 9, and 10, suggesting a potential mechanism by which effector T cells are recruited to islets during ICI therapy. Immunophenotyping of islet-infiltrating immune cells indeed showed increased IFNγ+CXCR6+ effector CD8+ cells in anti-PD1 treated mice compared to isotype-treated controls. Moreover, these IFNγ+CXCR6+CD8+ T cells stained positively for the NRP-V7 mimotope tetramer, a known antigen for CD8+ T cells in spontaneous autoimmune diabetes in NOD mice, suggesting this as an antigen-specific population contributing to the immunopathogenesis of ICI-T1DM. Finally, genetic deletion of CXCR6 in NOD mice delayed the onset of autoimmune diabetes during anti-PD1 treatment in female (p=0.0162) but not male mice (p=0.3656). In summary, these data further elucidate the cellular mechanisms by which IFNγ and chemokine signaling pathways drive the development of ICI-T1DM and identify the CXCR6-CXCL16 axis as a potential therapeutic target to prevent this IRAE in checkpoint inhibitor-treated cancer patients. Presentation: 6/2/2024

6529 The Risk of Hypophysitis Following Treatment With Relatlimab+Nivolumab Appears Higher Than Expected

Abstract Disclosure: N. Chamorro-Pareja: None. A.T. Faje: None. K.K. Miller: Stock Owner; Self; Bristol-Myers Squibb. Hypophysitis is a recognized complication of immune checkpoint inhibitor therapy; the risk of developing hypophysitis in patients receiving nivolumab (an anti-programmed death-ligand 1 [anti-PD-1]) is estimated to be &amp;lt; 1%. Relatlimab is a human monoclonal antibody targeting lymphocyte activation gene 3 (LAG-3) recently approved in combination with nivolumab for the treatment of unresectable or metastatic melanoma. The risk of hypophysitis as a complication of relatlimab therapy is not well-defined. Objective: To examine the prevalence, identify risk factors, and characterize the clinical presentation of hypophysitis in patients receiving relatlimab+nivolumab. Methods: 159 patients received relatlimab+nivolumab at the Mass General Brigham health care system between 6/2015 and 11/2023. Twenty-seven patients were excluded because they were either diagnosed with adrenal insufficiency (AI) before receiving relatlimab+nivolumab or AI was secondary to other factors, primarily exogenous glucocorticoid administration, leaving a total of 122 patients. The medical records of these patients, including provider encounters, laboratory results, medication records, and radiologic images were reviewed. Data are presented as mean ± SD. Results: Central AI was diagnosed in 10 patients (7.5% of the cohort) after relatlimab+nivolumab administration. The mean age was 64.5±13.8 vs. 67.1±14.4 in patients with AI vs. patients without AI (p= 0.58). Sixty percent of patients in the AI group were male compared to 53% of patients without AI (p= 0.68). The development of AI was not related to the cumulative dose of relatlimab+nivolumab (mean number of cycles 6.4±3.2 vs. 4.9±5.0, p=0.35). The most common presenting symptoms of AI were fatigue, anorexia, nausea, and vomiting. No patients were diagnosed with additional anterior pituitary hormone deficiencies, though not all patients were evaluated for these diagnoses; none had diabetes insipidus. Nine patients had MRIs performed after the diagnosis of central AI; 7 of these patients had pre-treatment MRIs for comparison. Diffuse pituitary enlargement was seen on MRI after initiation of relatlimab+nivolumab in 3 patients up to 8 weeks prior to the diagnosis of hypopituitarism. All patients had persistent hypopituitarism at the most recent evaluation. Conclusions: This study is the first cohort analysis of hypophysitis in patients treated with relatlimab+nivolumab. A significant portion of patients were diagnosed with central AI, presumptively due to hypophysitis given the lack of an identifiable alternative etiology. Although the clinical phenotype of these patients paralleled published studies analyzing anti-PD-1 monotherapy, combination treatment with relatlimab+nivolumab appeared to confer a significantly higher risk of developing hypophysitis. Presentation: 6/3/2024

Neudesin regulates dendritic cell function and antitumor CD8+ T cell immunity

Dendritic cells (DCs) are essential for antitumor T-cell responses to immune checkpoint inhibitor therapies. We have previously reported that the secreted protein neudesin suppresses DC function. In contrast, neudesin has been found to be abundantly expressed in human cancers. In this study, we evaluated the role of neudesin in cancer immunity. Cancer-related database analysis revealed that patients with melanoma with low neudesin expression exhibited increased infiltration of DCs and CD8+ T cells and improved outcomes of checkpoint inhibitor therapy. In mouse tumor models, neudesin deficiency delayed tumor growth and increased the proportions of Type 1 conventional DCs (cDC1s) and tumor antigen-specific CD8+ T cells in tumors and tumor-infiltrating lymph nodes. Neudesin-deficient antitumor cDC1 vaccine enhanced the systemic immunity more effectively than the wild-type cDC1 vaccine. Overall, our findings highlight the importance of neudesin in cancer immunity, providing a novel target for immunotherapy.

Predictive value of ZFHX4 mutation for the efficacy of immune checkpoint inhibitors in non-small cell lung cancer and melanoma.

Studies have shown that the Zinc finger homeobox 4 (ZFHX4) might be a factor in the prognosis of malignancies. However, little is known about the association between the ZFHX4 mutation and the effectiveness of immune checkpoint inhibitors (ICIs) in non-small cell lung cancer (NSCLC) and melanoma. Three public ICIs-treated NSCLC cohorts were divided into discovery cohort (n=75) and validation cohort (n=62), which were used to evaluate the relationship between ZFHX4 mutation and ICIs effectiveness in NSCLC. Seven ICIs-treated melanoma cohorts (n = 418) were used to analyze the relationship between ZFHX4 mutation and immunotherapy efficacy in melanoma. NSCLC and skin cutaneous melanoma (SKCM) cohorts from The Cancer Genome Atlas (TCGA) were used to investigate underlying mechanism. Patients with ZFHX4 mutant-type (ZFHX4-Mut) showed a superior objective response rate (ORR) (P < 0.01) and longer progression-free survival (PFS) (P < 0.05) than patients with ZFHX4 wild-type (ZFHX4-WT) in NSCLC cohorts. In the melanoma cohorts, patients carrying ZFHX4-Mut had a higher ORR (P = 0.042) and longer overall survival (OS) (P = 0.011). Besides, patients with NSCLC and melanoma harboring ZFHX4-Mut had a higher tumor mutation burden (TMB) (P<0.001) and tumor neoantigen burden (TNB) (P<0.001) than those harboring ZFHX4-WT. ZFHX4 mutation was associated with higher levels of plasma B cells, activated CD4+ memory T cells, and CD8+ T cells. Seven DNA damage repair pathways were significantly enriched in the ZFHX4-Mut group. ZFHX4 mutation could serve as a predicter for the efficacy of ICIs therapy in NSCLC and melanoma.

Longitudinal assessment of health-related quality of life in Japanese patients with advanced urothelial carcinoma receiving immune check point inhibitors

Real-world data on health-related quality of life (HRQoL) in advanced urothelial carcinoma (aUC) receiving immune checkpoint inhibitors (ICIs) are limited. This study included 42 patients with aUC who received second-line or later pembrolizumab (n = 19), maintenance avelumab followed by first-line chemotherapy (n = 13), or adjuvant nivolumab after radical surgery (n = 10). Time-course changes in the domains and scales related to HRQoL were evaluated using the EORTC QLQ-C30, FACT-G, and SF-8 questionnaires during ICI therapy. Anchor-based approaches for minimally important differences were determined as ‘improved’, ‘stable’, and ‘deteriorated’. We found significant improvements after the start of pembrolizumab treatment on many scales. Almost none of the scales changed significantly in the avelumab and nivolumab groups. Approximately 80% of the pembrolizumab group had deteriorated social/family well-being in FACT-G. Approximately 60% of the patients in the avelumab group had deteriorated general health and vitality in SF-8. In the nivolumab group, none of the scales deteriorated in > 50% of the patients. Deterioration of physical function in the SF-8 was associated with occurrence of treatment-related adverse events ≥ grade 2 during ICI therapy (P = 0.013). Our findings demonstrated that majority of patients with aUC who received ICI therapy had a stable HRQoL, which was consistent with evidence from clinical trials.

Oncogenic KRAS drives immunosuppression of colorectal cancer by impairing DDX60-mediated dsRNA accumulation and viral mimicry.

The interferon (IFN) response is vital for the effectiveness of immune checkpoint inhibition (ICI) therapy. Our previous research showed that KRAS (Kirsten rat sarcoma viral) mutation impairs the IFN response in colorectal cancer (CRC), with an unclear mechanism. Here, we demonstrate that KRAS accelerates double-stranded RNA (dsRNA) degradation, impairing dsRNA sensing and IFN response by down-regulating DExD/H-box helicase 6 (DDX60). DDX60 was identified as a KRAS target here and could bind to dsRNAs to protect against RNA-induced silencing complex (RISC)-mediated degradation. Overexpressing DDX60 induced dsRNA accumulation, reactivated IFN signaling, and increased CRC sensitivity to ICI therapy. Mechanistically, KRAS engaged the AKT (also known as protein kinase B)-GSK3β (glycogen synthase kinase-3 beta) pathway to suppress STAT3 phosphorylation, thereby inhibiting STAT3-driven DDX60 transcription. Our findings reveal a role for KRAS in dsRNA homeostasis, suggesting potential strategies to convert "cold" tumors to "hot" and to overcome ICI resistance in CRC with KRAS mutations.

Clinicogenomic predictors of outcomes in patients with hepatocellular carcinoma treated with immunotherapy.

Immune checkpoint inhibitor (ICI) combinations extend overall survival (OS) while anti-PD-1/L1 monotherapy is non-inferior to sorafenib in treatment-naïve, patients with advanced hepatocellular carcinoma (HCC). Clinicogenomic features are posited to influence patient outcomes. The primary objective of this retrospective study was to define the clinical, pathologic, and genomic factors associated with outcomes to ICI therapy in patients with HCC. Patients with histologically confirmed advanced HCC treated with ICI at Memorial Sloan Kettering Cancer Center from 2012 to 2022 were included. Association between clinical, pathological, and genomic characteristics were assessed with univariable and multivariable Cox regression model for progression-free survival (PFS) and OS. Two-hundred and forty-two patients were treated with ICI-based therapy. Patients were predominantly male (82%) with virally mediated HCC (53%) and Child Pugh A score (70%). Median follow-up was 28 months (0.5-78.4). Median PFS for those treated in 1st line, 2nd line and ≥ 3rd line was 4.9 (range: 2.9-6.2), 3.1 (2.3-4.0), and 2.5 (2.1-4.0) months, respectively. Median OS for those treated in 1st line, 2nd line, and ≥ 3rd line was 16 (11-22), 7.5 (6.4-11), and 6.4 (4.6-26) months, respectively. Poor liver function and performance status associated with worse PFS and OS, while viral hepatitis C was associated with favorable outcome. Genetic alterations were not associated with outcomes. Clinicopathologic factors were the major determinates of outcomes for patients with advanced HCC treated with ICI. Molecular profiling did not aid in stratification of ICI outcomes. Future studies should explore alternative biomarkers such as the level of immune activation or the pretreatment composition of the immune tumor microenvironment.

Regulatory Role of IL6 in Immune-Related Adverse Events during Checkpoint Inhibitor Treatment in Melanoma

The landscape of clinical management for metastatic melanoma (MM) and other solid tumors has been modernized by the advent of immune checkpoint inhibitors (ICI), including programmed cell death-1 (PD-1), programmed cell death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitors. While these agents demonstrate efficacy in suppressing tumor growth, they also lead to immune-related adverse events (irAEs), resulting in the exacerbation of autoimmune diseases such as rheumatoid arthritis (RA), ulcerative colitis (UC), and Crohn’s disease (CD). The immune checkpoint inhibitors offer promising advancements in the treatment of melanoma and other cancers, but they also present significant challenges related to irAEs and autoimmune diseases. Ongoing research is crucial to better understand these challenges and develop strategies for mitigating adverse effects while maximizing therapeutic benefits. In this manuscript, we addressed this challenge using network-based approaches by constructing and analyzing the molecular and signaling networks associated with tumor-immune crosstalk. Our analysis revealed that IL6 is the key regulator responsible for irAEs during ICI therapies. Furthermore, we conducted an integrative network and molecular-level analysis, including virtual screening, of drug libraries, such as the Collection of Open Natural Products (COCONUT) and the Zinc15 FDA-approved library, to identify potential IL6 inhibitors. Subsequently, the compound amprenavir was identified as the best molecule that may disrupt essential interactions between IL6 and IL6R, which are responsible for initiating the signaling cascades underlying irAEs in ICI therapies.