Toxicity Of Immunotherapy Research Articles

Toxicity surveillance in FDA pivotal registration trials for immune checkpoint inhibitors: Are we missing the mark?

215 Background: Immune checkpoint inhibitors (ICIs) have changed the treatment landscape for a multitude of malignancies, leading to prolonged survival and durable responses. Despite this, a significant number of patients will develop immune-related adverse events (irAEs) with significant associated morbidity and mortality. A retrospective study has previously demonstrated that 28% of patients can develop IrAEs from 6 months up to 2 years after starting therapy (1). Surveillance for toxicity is essential for understanding the long-term risk associated with ICIs. We aimed to analyze the reporting timeframes used in clinical trials of immuno-oncology agents leading to FDA approval. Methods: In this retrospective study, we interrogated the HemeOnc knowledgebase to curate a list of all clinical trial publications leading to FDA approval from 2011 to 2024. We manually selected from this list any trial including an immune checkpoint inhibitor either as monotherapy or in combination with another systemic therapy. The adverse event follow-up time was then extrapolated by manually reviewing the trial publication, supplemental materials or the trial protocol depending on where this information was listed. All trials were categorized based on trial initiation dates. Results: We identified 175 clinical trials leading to FDA approvals, with trial initiation dates ranging from 2004 to 2019. 165 trials were included in the analysis with 10 being excluded due to lack of language regarding follow-up. 62% of the trials included were Phase III trials with the remaining 38% Phase I/II trials. The median follow-up days for all trials across this timeframe was 90, with a range of 28 to 135. The median follow-up time for AE monitoring increased by nearly 30%, rising from 70 days in 2004 to 90 days in 2013. Subsequently, we observed a consistent median follow-up time of 90 days (28 to 130 days) from that point onward, with no further increase. Conclusions: To our knowledge this is the first systematic review of IrAE monitoring in clinical trials leading to FDA approval. In our study we revealed that, despite advancements in the understanding of IrAEs and their potential for late presentation, registration trials leading to regulatory approval remain inadequately designed to capture chronic and delayed immunotherapy toxicities. As these therapies advance into earlier stages of disease with longer life expectancy, it will be critical for regulatory bodies, study sponsors, and trial investigators to either redesign clinical trials or for there to be an alternative method that comprehensively captures the incidence and pattern of late-presenting toxicities. 1. Durbin, ASCO 2023.

Impact of a pilot advanced provider-based comprehensive management program to support patients with immunotoxicity-related adverse events in a cancer care setting.

31 Background: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of many types of cancers. Despite the clinical benefits of the targeted therapy, its use is associated with a spectrum of autoimmune side effects known as immune-related adverse events (irAEs). Toxicities are distinct from those associated with standard chemotherapy, and, if unrecognized and not managed aggressively, can become life-threatening. Early recognition and management of these toxicities, as well as approaches toward cautious retreatment following resolution is essential in clinical practice. Methods: As part of larger effort to provide efficient and proactive care to patients, advanced provider-based comprehensive management program was established in an academic hospital ambulatory setting to identify and manage the full spectrum of unique toxicities of patients receiving standard-of-care ICIs. The goal of the program was to manage patients with severe toxicity including seamless transitions of care between outpatient and inpatient settings to obviate the need for future acute care utilizations. The program provided real-time guidance to providers with clinical questions on use of ICIs, actively navigated patients with suspected immunotherapy toxicity and assessed ongoing education needs for both outpatient and inpatient services. A retrospective analysis of 2-year post implementation of the program was performed with inpatient to outpatient referrals as primary outcome and median length of stay and 30-day readmission rate as secondary outcomes. Results: A total of 388 inpatient admissions (222 Year-1 and 166 Year-2) were included. Preliminary analysis revealed a 25% decrease in immunotoxicity related inpatient admissions (admission rate decreased from 2.8 to 1.9) while patients treated with immunotherapy increased by 7%. The number of ambulatory encounters with the navigator increased by 40% (362 vs 509). The median length of stay for those on the dedicated program decreased by 27.3% (5.5 vs. 4 days) and the 30-day readmission rate decreased by 15.8% (24.3 vs. 20.5) from Year 1 to Year 2. Conclusions: Preliminary analysis suggests the program improved patient care, provided timelier follow-up and management, and reduced the delay to return to anti-cancer treatment. The ambulatory program provided proactive intervention, diagnosis, and management of immunotherapy related toxicities, preventing hospitalization and readmission to the hospital. Although initial findings suggest improved preliminary outcomes, further analysis is required to make any causal inference on the true and sustainable impact of the intervention.

EP.04E.03 Enzymomics of Bodily Fluids Captures CD38-Orchestrated Immunometabolic Disorder for Early Detection of Immunotherapy Toxicity

EP.04E.03 Enzymomics of Bodily Fluids Captures CD38-Orchestrated Immunometabolic Disorder for Early Detection of Immunotherapy Toxicity

Endocrine toxicity of cancer immunotherapy

Endocrine toxicity of cancer immunotherapy

Parallel explorations in LA-NSCLC: Chemoradiation dose-response optimisation considering immunotherapy and cardiac toxicity sparing

Background and purposeChemoradiotherapy (CRT) for locally-advanced non-small cell lung cancer (LA-NSCLC) has undergone advances, including increased overall survival (OS) when combined with immune checkpoint blockade (ICB), and using cardiac-sparing techniques to reduce the radiotoxicity. This research investigated 1) how radiotherapy schedules can be optimised with CRT-ICB schemes, and 2) how cardiac-sparing might change the OS for concurrent CRT (cCRT). Methods and materialsSurvival data and dosimetric indices were sourced from published studies, with 2-year OS standardised and the hazard ratio of mean heart dose (MHD) against radiotoxicity tabulated in purpose. A published CRT dose–response model was selected, then modified with ICB and cardiac-sparing hypotheses. Models were maximum likelihood fitted, then visualised the prediction outcomes after bootstrapping. ResultsThe modelled 2-year OS rate of cCRT-ICB reached 71 % (95 % confidence intervals, CI 62 %, 84 %) and 66 % (95 % CI: 53 %, 81 %) for stage IIIA and IIIB/C, respectively, given 60 Gy in 2 Gy-per-fraction. 60 Gy in 30 fractions remained the best schedule for cCRT-ICB, whereas modest dose de-escalation to 55 Gy only reduced the OS in 2 %. Sequential CRT (sCRT)-ICB provided 6 % OS increases versus the best OS rate achieved by sCRT alone. Photon MHD-sparing achieved a 5–10 % increase in modelled 2-year OS, with protons providing a further roughly 5–10 % increase. ConclusionNeither dose-escalation nor de-escalation relative to 60 Gy in 30 fractions influenced the survival with cCRT-ICB, while 5 Gy dose de-escalation might benefit patients with heavily irradiated organs at risk. Cardiac-sparing improved OS, and protons provided advantages for tumours anatomically overlapped or lay below the heart.

From Genotype to Phenotype: Raman Spectroscopy and Machine Learning for Label-Free Single-Cell Analysis.

Raman spectroscopy has made significant progress in biosensing and clinical research. Here, we describe how surface-enhanced Raman spectroscopy (SERS) assisted with machine learning (ML) can expand its capabilities to enable interpretable insights into the transcriptome, proteome, and metabolome at the single-cell level. We first review how advances in nanophotonics-including plasmonics, metamaterials, and metasurfaces-enhance Raman scattering for rapid, strong label-free spectroscopy. We then discuss ML approaches for precise and interpretable spectral analysis, including neural networks, perturbation and gradient algorithms, and transfer learning. We provide illustrative examples of single-cell Raman phenotyping using nanophotonics and ML, including bacterial antibiotic susceptibility predictions, stem cell expression profiles, cancer diagnostics, and immunotherapy efficacy and toxicity predictions. Lastly, we discuss exciting prospects for the future of single-cell Raman spectroscopy, including Raman instrumentation, self-driving laboratories, Raman data banks, and machine learning for uncovering biological insights.

Computational Approach for the Development of pH-Selective PD-1/PD-L1 Signaling Pathway Inhibition in Fight with Cancer.

Immunotherapy, particularly targeting the PD-1/PD-L1 pathway, holds promise in cancer treatment by regulating the immune response and preventing cancer cells from evading immune destruction. Nonetheless, this approach poses a risk of unwanted immune system activation against healthy cells. To minimize this risk, our study proposes a strategy based on selective targeting of the PD-L1 pathway within the acidic microenvironment of tumors. We employed in silico methods, such as virtual screening, molecular mechanics, and molecular dynamics simulations, analyzing approximately 10,000 natural compounds from the MolPort database to find potential hits with the desired properties. The simulations were conducted under two pH conditions (pH = 7.4 and 5.5) to mimic the environments of healthy and cancerous cells. The compound MolPort-001-742-690 emerged as a promising pH-selective inhibitor, showing a significant affinity for PD-L1 in acidic conditions and lower toxicity compared to known inhibitors like BMS-202 and LP23. A detailed 1000 ns molecular dynamics simulation confirmed the stability of the inhibitor-PD-L1 complex under acidic conditions. This research highlights the potential of using in silico techniques to discover novel pH-selective inhibitors, which, after experimental validation, may enhance the precision and reduce the toxicity of immunotherapies, offering a transformative approach to cancer treatment.

Immune related adverse events in patients with breast cancer and autoimmune disease treated with immunotherapy.

1103 Background: Pembrolizumab is approved for early and advanced triple negative breast cancer (TNBC), and atezolizumab was approved for advanced TNBC. Toxicity of immunotherapy (IO) and immune related adverse events (irAEs) in patients with breast cancer with an underlying autoimmune disease are not well understood as autoimmune disease is often an exclusion criterion in immunotherapy trials. Understanding real-world IO toxicity and irAEs in patients with breast cancer and autoimmune disease may inform clinical decision making. Methods: We studied IO toxicity and irAEs in patients with early and metastatic breast cancer, and underlying autoimmune disease vs. those without autoimmune disease (at IO start) who received IO at an academic institution. A retrospective review was conducted to identify IO toxicity and irAEs (CTCAE v 5.0). Cohorts were compared with Pearson’s chi-squared test (categorical variables) and Wilcoxon rank-sum test (continuous variables), with p<0.05 for statistical significance. Results: Cohorts had 23 patients with breast cancer and ≥1 autoimmune disease (AD) prior to receipt of IO (thyroid: 48%, rheumatologic: 26%, gastrointestinal: 13%, dermatologic: 9%), and 106 patients with breast cancer but without autoimmune disease (non-AD). Median age at IO start was 63 (interquartile range [IQR] 54-69) in AD vs. 50 in non-AD (IQR 39-59). Stage I-III/IV distribution was 39%/61% for AD and 67%/33% in non-AD. IO was mainly pembrolizumab (AD: 87%; non-AD: 85%) vs. atezolizumab. Table depicts characteristics of IO toxicity. A significantly higher overall rate of irAEs was seen in AD (96%) vs. non-AD (59%) [p<0.001]. Significantly greater immune related transaminitis was observed in AD (52%) vs. non-AD (24%) [p=0.006]. Immune related hypothyroidism (AD: 30% vs. non-AD: 15%, p=0.08), nephritis (AD: 9% vs. non-AD 2%, p=0.08), and hyperthyroidism (AD: 9% vs. non-AD: 3%, p=0.19) had numerically higher rates in AD, but these findings did not achieve statistical significance. Flare of the baseline AD with IO was observed in 6/23 (26%) patients, and 50% of flares occurred within 1 month of starting IO (range 1-5 months). Management of irAEs was similar in AD vs. non-AD, and rates of full resolution of irAEs were similar (AD: 55%; non-AD: 61%, p=0.65). Late onset irAEs (> 3 months after IO discontinuation) were rare (AD: 12%; non-AD: 4%, p=0.21). Conclusions: A higher overall rate of irAEs was observed in patients with underlying autoimmune disease, including greater immune related transaminitis and flare of the underlying autoimmune disease, suggesting the need for close monitoring of irAEs in this population. [Table: see text]

Predicting immunotherapy toxicity through single-cell sequencing of peripheral immune cells: A pilot study.

e14538 Background: Immune checkpoint inhibitors are widely used in oncology. However, immune-related adverse events (iRAEs) are idiosyncratic and can be severe. The overall incidence is 27%, with severe iRAEs occurring in 6% of patients. We hypothesised that distinct immune cell phenotypes (gene expression) correlate with immune-related toxicity from checkpoint inhibitor immunotherapy. Single-cell RNA sequencing (scRNA-seq) is a powerful tool that can assay the gene expression of thousands of individual cells. RPS26 expression mediates CD4/CD8 T cell activation through a known trans-expressive quantitative trait locus at rs1131017 and is linked with autoimmunity. FOS and JUN encode for c-Fos and c-Jun, which dimerise to create the activator protein-1 complex, a well-established transcriptional factor of the immune system. c-Fos is an immunoregulator known to suppress pro-inflammatory cytokines, suggesting that c-FOS deficiency plays a crucial role in developing autoimmunity. We aimed to analyse the transcriptomic differences of peripheral immune cells between patients who experienced severe checkpoint inhibitor therapy iRAE and those who did not. Methods: We identified a pilot cohort of eight patients who developed grade three or above toxicity due to immune checkpoint inhibitors and eight controls who were matched for age, cancer and treatment type. Peripheral blood mononuclear cells were collected prospectively at baseline and two subsequent treatment cycles. Cells were captured on the 10x Chromium platform, and libraries were sequenced to 30,000 reads per cell. Samples were demultiplexed, and the data was analysed with the Seurat package on R statistical software (version 4.3.0). Results: Five patients had baseline samples only, two patients had two samples from two cycles, and one patient had samples from three cycles. After quality control filtering, we identified 36,288 cells from 16 individuals and 24 samples. Immune cells were annotated with the Azimuth package into 29 subtypes. We identified differences in cell proportions of immune cell subsets in the toxicity vs control group, including B naive cells (5.57% vs 3.71% p=0.01) and reduced cytotoxic CD4 T lymphocyte cells (0.66% vs 2.26%, p=0.005). Differential gene expression analysis identified a significantly high expression of ribosomal genes, particularly RPS26, in multiple cell types at baseline (p<0.01) and reduced expression of FOS and JUN-related genes in CD14 and CD16 monocytes, CD4 and CD8 T cells in the toxicity cohort (p<0.01). Conclusions: Overexpression of ribosomal genes and reduced expression of FOS/ JUN genes amongst PBMCs at baseline are potentially predictive biomarkers of severe checkpoint inhibitor immunotherapy toxicity. Validation of these findings in a larger cohort is in progress.

Screening for ocular toxicities of immunotherapy in a real-world population.

e24125 Background: Nivolumab, Pembrolizumab, and Ipilimumab have revolutionized the treatment of melanoma. However, patients receiving these treatments risk immunotherapy-related adverse events (IRAEs). IRAEs can occur in any organ system, are treated with steroids or immunosuppressive medications, and may require treatment delay or discontinuation. Ocular IRAEs, which are caused by off-target reactions with ocular immune mechanisms, are often identified after significant damage to the eye. Ocular IRAEs are rare in the literature with an approximate prevalence of 3.3%. After observing intraocular inflammation (uveitis) with uveal depigmentation (pigment release) in some patients receiving immunotherapy, we hypothesized that the rate of such events in a real-world population may be higher than previously reported. We predict ophthalmic screening and early intervention may prevent severe and potentially permanent ocular IRAEs. Methods: Patients starting immunotherapy for melanoma were referred to an ocular screening clinic at the Cancer Centre of Southeastern Ontario (Queen’s University, Kingston, Canada) for baseline ocular assessments. Repeat assessments occurred every three months (single agent) or at every cycle (dual immunotherapy). Intake visits included examination by an attending ophthalmologist, including examination for uveitis and anterior chamber free pigment under high-powered field. Intraocular inflammation (IOI) was defined as the presence of endothelial deposits and/or anterior chamber cell and/or pigment that was not present at baseline. Ocular findings were monitored alongside other IRAEs during treatment. Results: 28 patients (17 male, 11 female) receiving adjuvant (46.4%) or palliative (53.6%) immunotherapy for melanoma were evaluated. 9 of these patients received dual immunotherapy (Ipilimumab/Nivolumab) and 19 received single agent immunotherapy. IOI was identified in 11 patients (39.2%), while only 4 presented with symptoms. None of the patients had overt signs of anterior segment inflammation such as erythema, conjunctival injection, and chemosis. IOI developed in 54.5% of dual immunotherapy-treated patients. Patients with ocular IRAEs were treated with topical/systemic steroids or other immunosuppressive medications. None required discontinuation of immunotherapy. The development of IOI was more common in metastatic patients whose cancer was responding to immunotherapy, and many of these patients sustained IRAEs in other organ systems. Conclusions: Our findings suggest IOI related to ocular IRAEs are quite common and develop in a third of patients receiving immunotherapy for melanoma. Ocular screening for IOI identified early, often asymptomatic toxicities that could progress to permanent visual disability. Further evaluation of dedicated ocular screening is indicated in patients receiving immunotherapy.

Intralesional nivolumab in oral potentially malignant disorders: A phase 1 pilot study on safety, tolerability, and preliminary efficacy.

6016 Background: Oral Potentially Malignant Disorders (OPMD) encompass a diverse group of oral mucosal diseases, including the prevalent oral leukoplakia (OL), serving as precursors to invasive oral squamous cell carcinoma. OPMD exhibits an annual malignant transformation rate up to 36%. Despite the breadth of research on OPMD the standard-of-care remains surgery or observation. We aim to evaluate the safety and tolerability of intralesional injections of Nivolumab in patients with OPMD. Secondary objectives include assessing objective response rate and pathologic complete response rate. We describe the results of an immune prevention trial designed to avoid systemic toxicities of immunotherapy in patient with pre-malignancy by administrating aPD1 intralesionaly. Methods: Phase 1, single-arm, open-label, dose-escalation pilot study that involves intralesional injections of Nivolumab (index lesion) in patients with high-risk OPMD lesions every 3 weeks (total of 4 doses, 12 weeks). Non-index, non-injected, oral lesion(s) were also documented and monitored. The study includes two dose cohorts (10 mg and 20 mg) to assess maximally tolerated dose with a 3 + 6 dose-escalation design. Adverse events were reported according to NCI CTCAE Version 5.0. Serial biopsies at baseline and up to 8 weeks after treatment were taken to assess efficacy using a composite score (i.e., size and degree of dysplasia) in index lesion. Major response was defined as >80% decrease in score; partial response as 40%-80% decrease. Freshly frozen tumors were subjected to RNA sequencing and gene pathway analysis to identify biomarkers of response or progression. Results: At the time of data analysis, 13 patients have completed treatment (61.5% males), both dose levels were well tolerated. The adverse event grades ranged from grade 1 (i.e. diarrhea, elevated LFT and skin rash) constituting the majority at 80.5% of reported adverse events, grade 2 (i.e. skin rash, cellulitis) at 13.9%, and grade 3 (i.e. hypertension) at 5.6%. Ten patients had multifocal disease. Major response was observed in 22.5% and partial response in 50% of the patients. One patient progressed to invasive SCC in a non-index lesion. RNA sequencing based immune phenotyping revealed increased infiltration of CD8 cytotoxic T cells in index lesions after treatment. Pathway analysis revealed significant alterations in immune pathways including Th1 and Th2 pathways, Natural killer and immunoregulatory pathways. Spatial transcriptome analysis and pharmacokinetics data are pending. Conclusions: Intralesional nivolumab is well tolerated in OPMD with suggested potential biological and clinical activity. A randomized phase II trial to assess cancer free survival is recommended to determine the efficacy in preventing cancer progression. We recommend dose of 20mg for phase II as it was well tolerated. Clinical trial information: NCT05327270 .

Immunotherapy toxicity prediction in patients with melanoma using machine learning algorithms.

e21567 Background: Immune checkpoint inhibitor (ICI) related toxicity is common in melanoma patients, but identifying who will experience toxicity can be challenging. Precision medicine tools that accurately predict ICI toxicity could improve patient outcomes. This study aimed to use Machine Learning (ML) to predict ICI toxicity in patients with melanoma. Methods: 384 datasets were available for patients started on immunotherapy between 2014-2023 in a single, large regional cancer center in Kent, U.K. Raw data was preprocessed using a standard scaling function and one hot encoding, followed by SMOTE to balance the imbalanced classes. Six ML algorithms were developed using 80% of the training data, tested on 20% of validation data and used the Grid Search Cross-Validation technique for hyperparameter optimization. Shapley Additive Explanations (SHAP) explainable artificial intelligence was used to interpret the toxicity prediction model to improve the interpretation and transparency of the decision boundary. Results: Of the 384 patients, 112 patients (29%) had completely resected disease and then had adjuvant treatment while 272 (71%) were unresectable or had metastatic disease and had palliative treatment intent. In the metastatic setting, the commonest immunotherapy regimen was Pembrolizumab (155, 57%), followed by Ipilimumab/Nivolumab (85, 31%). The commonest regimen in the adjuvant setting was Pembrolizumab (86, 77%). 95 patients (25%) experienced ICI-related toxicity. The number of patients with Grades 1-4 toxicity was 2 ,4, 18 and 4 respectively, the remaining had unspecified toxicity grades. The commonest class of toxicity (CTCAE v5) was gastrointestinal (36, 38%), followed by endocrine (20, 21%) and skin (19, 20%). Linear Regression and Gaussian Naïve Bayes predicted toxicity with the most accuracy, 92% (Table 1). The model showed that increasing age, female gender and not receiving Nivolumab predicted toxicity. Regardless of the regimen or treatment intent, our ML model could also predict immunotherapy response with 90% accuracy. Conclusions: These ML algorithms used clinically available data to predict ICI toxicity accurately. Key predictors of toxicity included increasing age, female gender and not receiving Nivolumab in the setting of both adjuvant and palliative intent. Future work will aim to externally validate these models in other centers. We will also explore if models could be trained for use in patients treated with nivolumab in combination with new anti-LAG-3(relatlimab). [Table: see text]

Preoperative-postoperative immunotherapy as treatment of borderline resectable and oligoprogressive stage III B-D and IV melanoma

IntroductionPerioperative therapy has gained significant importance in patients with advanced melanoma. Currently, there is little data on the routine use of preoperative immunotherapy in metastatic melanoma outside clinical trials. This study aimed to evaluate the effectiveness of preoperative treatment in patients with borderline resectable stage III or IV melanoma as well as in oligoprogressing stage IV cases; the secondary aim is to describe the safety of surgery after immunotherapy. Materials and methodsSince 1/Jan/2016 seventeen patients were treated with curative intent neoadjuvant immunotherapy, surgery, and adjuvant immunotherapy, while nineteen patients were operated due to oligoprogression while treted with immunotherapy. Survival was analyzed using the Kaplan-Meier method and association between variables was tested using the chi-squared test. ResultsR0 resection was achieved in 76.5 % of cases after neoadjuvant immunotherapy. 24 % of patients achieved objective RECIST response and 35 % complete or major pathological response. At the median follow-up time of 51.4 months, 64.7 % of patients were free of PD after perioperative treatment, while 3-year RFS and OS rates were 68 % and 80.9 %, respectively. R0 resection was achieved in 73.7 % of oligo-progressing nodules. The median time to PD on immunotherapy after the first oligoprogression was 10.3 months. Immunotherapy did not result in any unexpected surgical complications. No patient died during preoperative treatment due to immunotherapy toxicity or disease progression. ConclusionsWe confirmed treatment safety and long-term disease control after perioperative immunotherapy. Patients with borderline resectable melanoma should be referred to reference centers using neoadjuvant immunotherapy.

Abstract PS14-01: Immune related adverse events in patients ≥65 years vs. <65 years with breast cancer treated with immunotherapy

Abstract Background: Pembrolizumab is approved for early/advanced triple negative breast cancer (TNBC), and atezolizumab was previously approved for advanced TNBC. Toxicity of immunotherapy (IO) and immune related adverse events (irAEs) in patients ≥65 years with TNBC is not described in detail in results from registration trials (KEYNOTE 522, KEYNOTE 355, and IMPassion130), where patients ≥65 years were a minority. Understanding real-world IO toxicity and irAEs in patients with breast cancer ≥65 years may inform clinical decision making. Methods: We studied IO toxicity and irAEs in patients with breast cancer ≥65 years vs. < 65 years (at IO start) who received IO at an academic institution. A retrospective review was conducted to identify IO toxicity and irAEs (classified by CTCAE v 5.0). Cohorts were compared with Pearson's chi-squared test (categorical variables) and Wilcoxon rank-sum test (continuous variables). Results: Cohorts had 25 patients ≥65 years (median age 73 years, interquartile range (IQR) 69-74 years) and 104 patients < 65 years (median age 48 years, IQR 39-56 years). Stage I-III/IV breast cancer distribution was 36%/64% for ≥65 years and 68%/32% for < 65 years. Baseline ECOG performance status was mainly 0-1 in both cohorts. IO was mainly pembrolizumab (≥65 years: 96%; < 65 years: 83% for first IO regimen) vs. atezolizumab. Table 1 depicts characteristics of IO toxicity. IO duration was longer in patients < 65 years. While rates of IO interruption for toxicity and discontinuation for toxicity were numerically higher in patients ≥65 years, these findings did not reach statisticial significance, possibly due to the sample size. Similar overall rates of irAEs were seen (≥65 years: 72%; < 65 years: 65%, p=0.47) but there were differences in the types of irAEs. Patients < 65 years had more transaminitis (≥65 years: 12%; < 65 years: 33%, p=0.04), and grade 2-3 hypothyroidism (among patients developing hypothyroidism, ≥65 years: grade 1- 75%, grade 2- 25%, grade 3- 0%; < 65 years: grade 1- 11%, grade 2- 79%, grade 3- 11%, p=0.017). Conversely, patients ≥65 years had higher rates of irAE nephritis (≥65 years: 12%; < 65 years: 1%, p=0.004); notably, none of the patients had baseline chronic kidney disease. Rates of full resolution of irAEs were similar between cohorts (≥65 years: 67%; < 65 years: 57%, p=0.47), but patients ≥65 years had more steroid use for management of first irAE while patients < 65 years required more thyroid hormone supplementation (first irAE management distribution, ≥65 years: steroids- 71%, thyroid hormone- 7%, supportive care- 21%; < 65 years: steroids- 31%, thyroid hormone- 25%, supportive care- 44%, p=0.025). Late onset irAEs and deaths from irAEs were rare in both cohorts, with 1 irAE related death in the cohort ≥65 years. Conclusions: In this real-world cohort, similar overall rates of irAEs were observed in patients ≥65 years and < 65 years. However, patients ≥65 years had higher rates of irAE nephritis and steroid use for irAEs, while patients < 65 years had more transaminitis and higher grade hypothyroidism, requiring more thyroid hormone supplementation. Given these age specific differences, validation in a larger cohort is merited. Table 1. Characteristics of IO toxicity. Citation Format: Neelima Vidula, Jennifer Hutchinson, Abigail McLaren, Lianne Ryan, Andrzej Niemierko, Aditya Bardia. Immune related adverse events in patients ≥65 years vs. <65 years with breast cancer treated with immunotherapy [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS14-01.

Abstract PO1-01-09: Neoadjuvant endocrine therapy and avelumab with or without palbociclib in stage II/III endocrine receptor-positive breast cancer: the ImmunoADAPT trial

Abstract Background: Pre-clinical and clinical data suggest that CDK4/6 inhibitors can promote an immunogenic tumor microenvironment (TME) and when combined with programmed cell death ligand 1 (PD-L1) inhibitors synergistic anti-cancer effects are observed. To understand the differential effects of CDK4/6 inhibition in the context of immunotherapy we designed a study evaluating neoadjuvant endocrine therapy (ET) with a PD-L1 inhibitor (avelumab) with or without a CDK4/6 inhibitor (palbociclib, palbo) in patients (pts) with stage II/III endocrine receptor (ER)-positive breast cancer. Methods: In this randomized phase 2 pilot study, pts with stage II/III ER+, HER2-negative breast cancer were randomized 2:1 to ET (aromatase inhibitor, AI, for post-menopausal pts; tamoxifen+/-ovarian function suppression for pre-menopausal pts) with avelumab, with or without palbo (palbo vs. control arms). Avelumab was added after a 1-month lead-in of ET +/- palbo, and all drugs were continued for additional 3-month-long cycles prior to surgery. We obtained tumor tissue and breast MRIs on C1D1, C2D1, and at the end of treatment. Imaging assessment was done according to RECIST 1.1 criteria at each time point. The primary endpoint was clinical complete response (cCR) by MRI in the palbo arm (H0: cCR=10% vs. 40% at a two-sided alpha level of 0.1). Secondary endpoints included pathologic CR (pCR), overall response rates (ORR), percent sum diameter changes, and adverse effects (AE). We report descriptive statistics on patient characteristics, clinical response rates, and changes in the sum of the longest diameters of the target lesions (SLD). Translational correlatives including imaging mass cytometry, spatial transcriptomic assessments, and other pathologic biomarkers will be reported at the meeting. Results: From 2018-2023, 33 pts were enrolled, and 30 were eligible for the primary analysis, including 20 pts on the palbo arm (1 pt with bilateral breast cancer, response to each breast cancer evaluated separately) and 10 to the control arm (1 pt with missing data). Clinical and pathologic characteristics were well balanced between arms, however, there was a higher proportion of patients with node-positive disease on the palbo arm (80% vs 60%). The study did not meet its primary endpoint as only 1 pt achieved a cCR and pCR in the palbo arm (cCR/pCR rate 4.8%) vs. no pts in the control arm. ORR was numerically higher in the palbo arm, 42.9% vs. 11.1% (p=0.204). After 1-month of ET+palbo, the mean SLD decreased by 11.6% compared to 9.4% in the ET-only control group (p=0.704). After avelumab was added to both arms, the mean SLD decreased by a further 15.2% in the palbo arm in contrast to a 6.9% increase in the control arm (p=0.018). Subgroup analysis in the palbo arm did not identify clinical or pathologic variables significantly associated with responses. No new safety or toxicity signals were observed. Notably, however expected, grade 3 or higher immune-related adverse events were observed including autoimmune diabetes (n=1), hepatitis (n=1), and colitis (n=1). Conclusions: As shown in previous studies, the addition of palbo to ET did not improve responses in the neoadjuvant setting; however, increased responses to palbo+ET were seen after PD-L1 inhibition, whereas not to ET, suggesting synergy between ET/palbo and avelumab. Translational correlative analysis will aim to decipher TME changes that augment PD-L1 inhibitor responses. Future studies in high-risk pts, where the toxicity of immunotherapy is acceptable, are warranted. Citation Format: Phaedon Zavras, Ruizhe Chen, Hanfei Qi, Mary Kate Jones, Ann Folmer, Hayden Chae, Allen Khodab, Ashley Cimino-Mathews, Lisa Jacobs, Lisa Mullen, Christie Hiton, Ahmed Elkhanany, Katia Khoury, Massimo Cristofanilli, Elizabeth Jaffee, Vered Stearns, Cesar Santa-Maria. Neoadjuvant endocrine therapy and avelumab with or without palbociclib in stage II/III endocrine receptor-positive breast cancer: the ImmunoADAPT trial [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-01-09.

Studying paired patient tissue and blood enables insights into immunotherapy toxicity.

Studying paired patient tissue and blood enables insights into immunotherapy toxicity.

Highly variable timing renders immunotherapy efficacy and toxicity impractical biomarkers of one another in clinical practice.

A useful clinical biomarker requires not only association but also a consistent temporal relationship. For instance, chemotherapy-induced neutropenia and epidermal growth-factor inhibitor-related acneiform rash both occur within weeks of treatment initiation, thereby providing information prior to efficacy assessment. Although immune checkpoint inhibitor (ICI)-associated immune-related adverse events (irAE) have been associated with therapeutic benefit, irAE may have delayed and highly variable onset. To determine whether ICI efficacy and irAE could serve as clinically useful biomarkers for predicting each other, we determined the temporal relationship between initial efficacy assessment and irAE onset in a diverse population treated with ICI. Using two-sided Fisher exact and Cochran-Armitage tests, we determined the relative timing of initial efficacy assessment and irAE occurrence in a cohort of 155 ICI-treated patients (median age 68 years, 40% women). Initial efficacy assessment was performed a median of 50 days [interquartile range (IQR) 39-59 days] after ICI initiation; median time to any irAE was 77 days (IQR 28-145 days) after ICI initiation. Median time to first irAE was 42 days (IQR 20-88 days). Overall, 58% of any irAE and 47% of first irAE occurred after initial efficacy assessment. For clinically significant (grade ≥2) irAE, 60% of any and 53% of first occurred after initial efficacy assessment. The likelihood of any future irAE did not differ according to response (45% for complete or partial response vs. 47% for other cases; P=1). In landmark analyses controlling for clinical and toxicity follow-up, patients demonstrating greater tumor shrinkage at initial efficacy assessment were more likely to develop future grade ≥2 (P=0.05) and multi-organ (P=0.02) irAE. In contrast to that seen with chemotherapy and molecularly targeted therapies, the temporal relationship between ICI efficacy and toxicity is complex and bidirectional. In practice, neither parameter can be routinely relied on as a clinical biomarker to predict the other.

59 Immunotherapy Toxicities in Real-World Use of Nivolumab & Ipilimumab in Pleural Malignant Mesothelioma: Experience from Sussex Cancer Centre

59 Immunotherapy Toxicities in Real-World Use of Nivolumab & Ipilimumab in Pleural Malignant Mesothelioma: Experience from Sussex Cancer Centre

Abstract 6676: Microbiome modification impacts PSCA directed chimeric antigen receptor (CAR) T cell therapy for prostate cancer

Abstract Background: There is growing evidence that responsiveness to immunotherapy is influenced by the composition of a patient’s gut microbiota. Recent analysis identified strong correlations between abundance of gut microbial species and positive response to immune based therapies in cancer patients. Further, enrichment of commensal microbes can promote immunostimulatory effects, immune based anti-tumor responses, and increased cytotoxic T cell abundance within the TME. Conversely, the presence of gut microbes known to cause inflammatory states in gut tissues may be correlated to negative immunotherapy outcomes or toxicities. To this end, we aimed to evaluate the impact of microbiome manipulation on gut microbe diversity, systemic immunity, local TME, and PSCA-targeted chimeric antigen receptor (CAR) T cell therapy in our established syngeneic prostate cancer mouse model. Methods: In an immune competent mouse model of PSCA+ prostate cancer developed in our lab, we sequentially modified the gut microbiome using antibiotic clearance followed by distinct human derived fecal matter transfers (CPI-FMT, HD-FMT, or No-FMT). Simultaneously, we treated microbiome modified tumor bearing mice with PSCA-targeting CAR T cells and measured differences in anti-tumor efficacy and survival. To provide mechanistic insight, we performed longitudinal whole genome sequencing (WGS) of fecal matter microbes and RNA sequencing on spleen and tissues following FMT administration. Results: In our model, a unique checkpoint inhibitor (CPI) treated patient derived human FMT (CPI-FMT) improved PSCA-CAR anti-tumor responses relative to healthy donor (HD-FMT) or No-FMT treatment controls. CPI-FMT administration also significantly improved overall survival in CAR T cell and non-targeting T cell control treated mice. Temporal analysis of microbes present in the gut following CPI-FMT and HD-FMT treatment show CPI-FMT treated mice exhibit favorable maintenance of gut microbe species richness and significant increase in microbiota diversity. We identify CPI-FMT provides an enrichment of specific microbes associated with preservation of gut homeostasis and improved immune response. RNA sequencing analysis on tumor tissues show differential transcription of immune related pathways following FMT which may influence immune and CAR T cell function. Conclusions: We show that our mouse prostate cancer model is sensitive microbiome modulation and can significantly impact PSCA-CAR T cell directed anti-tumor responses. Temporal WGS analysis of gut fecal matter reveal enrichment suggest specific species abundances which may promote gut homeostasis over dysbiosis or inflammatory states and may account for improved CAR T cell response. We aim to further develop this model to interrogate candidate targeted microbiome modifiers which may impact mechanisms which promote CAR T cell and immune function. Citation Format: John Paul Murad, Lea Christian, Yukiko Yamaguchi, Lupita Lopez, Ching Ouyang, Hirokazu Sato, Bryce Jarman, Sean Stromberg, Stephen J. Forman, Stephen Van Dien, Stephanie Culler, Saul J. Priceman. Microbiome modification impacts PSCA directed chimeric antigen receptor (CAR) T cell therapy for prostate cancer [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 6676.

Abstract 1167: Prospective analysis of pretreatment circulating CD4 memory T cell features associated with severe immunotherapy toxicity

Abstract Introduction: Immune checkpoint inhibitors (ICIs) have revolutionized melanoma treatment, significantly improving outcomes. Nevertheless, too many melanoma patients undergoing ICI treatment experience severe and often debilitating immune-related adverse events (irAEs). In a retrospective melanoma cohort treated with ICIs, we previously found that elevated baseline levels of circulating CD4 effector memory T (TEM) cells were associated with the development of severe irAEs, irrespective of the affected organ system (Lozano et al., Nature Medicine, 2022). Here, we present data from an extended prospective validation cohort from 47 patients across two academic medical centers. Methods: Of 47 patients, 26 received combination anti-PD1/anti-CTLA4 ICIs, 3 combination anti-PD1/anti-LAG3 ICIs, 17 anti-PD1 ICI, and 1 anti-CTLA4 ICI. Peripheral blood mononuclear cells (PBMCs) were prepared from pretreatment (Cycle 1 Day 1) blood samples obtained from all patients. We performed mass cytometry (CyTOF) on PBMCs using a 38-marker panel to deeply profile immune subsets. We further leveraged bulk RNA-seq from 24 patients to (i) deconvolve CD4 memory T cell abundance using CIBERSORTx and (ii) determine T cell receptor (TCR) diversity using Shannon entropy following MiXCR clonotype assembly. irAEs were graded on a 5-point scale using the Common Terminology Criteria for Adverse Events v5. Results: After treatment initiation, 14 patients experienced severe irAEs (grade 3+) at a median of 12.1 weeks (range 4-54), including 4 with life-threatening (grade 4) irAEs. CyTOF revealed elevated circulating CD4 TEM cells in patients that developed severe irAEs (P<0.0001; AUC=0.87), including those treated with combination ICIs (P=0.0001; AUC=0.89). We further observed a continuous relationship between increasing CD4 TEM levels and irAE grade (P=3e-6, Jonckheere-Terpstra test). We then combined CD4 memory T cell abundance and TCR diversity derived from bulk RNA-seq on 24 of these patients using logistic regression (trained on data from Lozano et al.) to yield a composite model score. The pretreatment composite model score was strongly associated with severe irAE development (P=0.0009, AUC=0.88), and in a median split, identified patients with shorter time to severe irAE development (3 months vs. not reached; P=0.006; HR=10.5). Notably, composite model features and the overall score had no significant association with immunotherapy benefit. Conclusion: In this prospective study, both circulating CD4 TEM levels determined by CyTOF and a composite model score measured by RNA-seq were strongly associated with severe irAE development, independent of response status. These findings hold promise for future pretreatment risk stratification of ICI therapy. Citation Format: Abul Usmani, Noah Earland, Wubing Zhang, Peter K. Harris, Antonietta Bacchiocchi, Chloe M. Sachs, Aishwarya Nene, David Y. Chen, Mario Sznol, Ruth Halaban, Aaron M. Newman, Aadel A. Chaudhuri. Prospective analysis of pretreatment circulating CD4 memory T cell features associated with severe immunotherapy toxicity [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 1167.