Molecular pathways and cellular subsets associated with adverse clinical outcomes in overlapping immune-related myocarditis and myositis.

Immune checkpoint therapies (ICTs) can induce life-threatening immune-related adverse events, including myocarditis and myositis, which are rare but often concurrent. The molecular pathways and immune subsets underlying these toxicities remain poorly understood. To address this need, we obtained heart and skeletal muscle biopsies for single-cell RNA sequencing in living patients with cancers treated with ICTs admitted to the hospital with myocarditis and/or myositis (overlapping myocarditis plus myositis, n=10; myocarditis-only, n=1) compared to ICT-exposed patients ruled out for toxicity utilized as controls (n=9) within 96 hours of clinical presentation. Analyses of 58,523 cells revealed CD8+ T cells with a cytotoxic phenotype expressing activation/exhaustion markers in both myocarditis and myositis. Furthermore, the analyses identified a population of myeloid cells expressing tissue-resident signatures and FcγRIIIa (CD16a), which is known to bind IgG and regulate complement activation. Immunohistochemistry of affected cardiac and skeletal muscle tissues revealed protein expression of pan-IgG and complement product C4d that were associated with the presence of high-titer serum autoantibodies against muscle antigens in a subset of patients. We further identified a population of inflammatory IL-1B+TNF+ myeloid cells specifically enriched in myocarditis and associated with greater toxicity severity and poorer clinical outcomes. These results are the first to recognize these myeloid subsets in human immune-related myocarditis and myositis tissues and nominate new targets for investigation into rational treatments to overcome these high-mortality toxicities.

A Modular Trial of Androgen Signaling Inhibitor Combinations Testing a Risk-Adapted Strategy in Patients with Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: To determine the efficacy and safety of risk-adapted combinations of androgen signaling inhibitors and inform disease classifiers for metastatic castration-resistant prostate cancers (mCRPC). EXPERIMENTAL DESIGN: In a modular, randomized phase II trial, 192 men were treated with 8 weeks of abiraterone acetate, prednisone and apalutamide (AAPA; Module 1), then allocated to Modules 2 or 3 based on Satisfactory (≥50% PSA decline from baseline and <5 CTC/7.5 mL) versus Unsatisfactory status. Men in the former were randomized to continue AAPA alone (Module 2A) or with ipilimumab (Module 2B). Men in the latter had carboplatin+cabazitaxel added to AAPA (Module 3). Optional baseline biopsies were subject to correlative studies. RESULTS: Median overall survival (from allocation) was 46.4 (95% CI 39.2, 68.2), 41.4 (95% CI 33.3, 49.9) and 18.7 (95% CI 14.3, 26.3) months in Modules 2A (n=64), 2B (n=64) and 3 (n=59) respectively. Toxicities were within expectations. Of 192 eligible patients, 154 (80.2%) underwent pre-treatment metastatic biopsies. The aggressive variant prostate cancer molecular profile (defects in ≥2 of p53, RB1, and PTEN) was associated with Unsatisfactory status. Exploratory analyses suggested SPP1+ and IGFBP2+ macrophages, druggable myeloid cell markers, and germline pathogenic mutations were enriched in the Unsatisfactory group. CONCLUSIONS: Adding ipilimumab to AAPA did not improve outcomes in men with androgen responsive mCRPC. Despite the addition of carboplatin+cabazitaxel, men in the Unsatisfactory group had shortened survivals. Adaptive designs can enrich for biologically and clinically relevant disease subgroups, to contribute to the development of marker-informed, risk-adapted therapy strategies in men with prostate cancer.

Integrative Molecular Analyses of the MD Anderson Prostate Cancer Patient-derived Xenograft (MDA PCa PDX) Series.

PURPOSE: Develop and deploy a robust discovery platform that encompasses heterogeneity, clinical annotation, and molecular characterization and overcomes the limited availability of prostate cancer models. This initiative builds on the rich MD Anderson (MDA) prostate cancer (PCa) patient-derived xenograft (PDX) resource to complement existing publicly available databases by addressing gaps in clinically annotated models reflecting the heterogeneity of potentially lethal and lethal prostate cancer. EXPERIMENTAL DESIGN: We performed whole-genome, targeted, and RNA sequencing in representative samples of the same tumor from 44 PDXs derived from 38 patients linked to donor tumor metadata and corresponding organoids. The cohort includes models derived from different morphologic groups, disease states, and involved organ sites (including circulating tumor cells), as well as paired samples representing heterogeneity or stages before and after therapy. RESULTS: The cohort recapitulates clinically reported alterations in prostate cancer genes, providing a data resource for clinical and molecular interrogation of suitable experimental models. Paired samples displayed conserved molecular alteration profiles, suggesting the relevance of other regulatory mechanisms (e.g., epigenomic) influenced by the microenvironment and/or treatment. Transcriptomically, models were grouped on the basis of morphologic classification. DNA damage response-associated mechanisms emerged as differentially regulated between adenocarcinoma and neuroendocrine prostate cancer in a cross-interrogation of PDX/patient datasets. CONCLUSIONS: We addressed the gap in clinically relevant prostate cancer models through comprehensive molecular characterization of MDA PCa PDXs, providing a discovery platform that integrates with patient data and benchmarked to therapeutically relevant consensus clinical groupings. This unique resource supports robust hypothesis generation and testing from basic, translational, and clinical perspectives.

Development of a Strategic Initiative at MD Anderson Cancer Center to Improve Outcomes in Immune-Related Adverse Events.

Immune checkpoint inhibitors (ICIs) have transformed the treatment paradigm for many cancer types. The clinical use of ICIs is increasing rapidly, including in combinations associated with increased risk of toxicities, termed "immune-related adverse events" (irAEs). Therefore, MD Anderson Cancer Center (MDACC) in Houston, Texas has proactively responded by developing a priority endeavor known as the Immuno-Oncology Toxicity (IOTOX) initiative. This strategic initiative aims to facilitate the seamless integration of key domains: (1) standardized clinical practice and innovative decision toolsets; (2) patient and provider education; and (3) a comprehensive clinical and translational research platform. The ultimate goal of this initiative is to develop and disseminate clinical best practices and biologic insights into irAEs to improve outcomes of patients with irAEs at MDACC and in the wider oncology community.

Evaluation of the Aggressive-Variant Prostate Cancer Molecular Signature in Clinical Laboratory Improvement Amendments (CLIA) Environments.

Aggressive-variant prostate cancers (AVPCs) are a subset of metastatic castrate-resistant prostate cancers (mCRPCs) characterized by defects in ≥ two of three of TP53, RB1, and PTEN (AVPCm), a profile linked to lineage plasticity, androgen indifference, and platinum sensitivity. Men with mCRPC undergoing biopsies for progression were assessed for AVPCm using immunohistochemistry (IHC), next-generation sequencing (NGS) of solid tumor DNA (stDNA), and NGS of circulating tumor DNA (ctDNA) assays in CLIA-certified labs. Biopsy characteristics, turnaround times, inter-reader concordance, and inter-assay concordance were assessed. AVPCm was detected in 13 (27%) patients via IHC, two (6%) based on stDNA, and seven (39%) based on ctDNA. The concordance of the IHC reads between pathologists was variable. IHC had a higher detection rate of AVPCm+ tumors with the shortest turnaround times. stDNA had challenges with copy number loss detection, limiting its detection rate. ctDNA detected the greatest proportion of AVPCm+ tumors but had a low tumor content in two thirds of patients. These data show the operational characteristics of AVPCm detection using various assays, and inform trial design using AVPCm as a criterion for patient selection or stratification.

Cardiometabolic healthcare for men with prostate cancer: an MD Anderson Cancer Center experience.

BACKGROUND: Men diagnosed with prostate cancer are at risk for competing morbidity and mortality due to cardiometabolic disease given their advanced age at diagnosis, high prevalence of pre-existing risk factors, and receipt of systemic therapy that targets the androgen receptor (AR). Expert panels have stressed the importance of cardiometabolic risk assessment in the clinic and proposed evaluating key risks using consensus paradigms. Yet, there is a gap in real-world evidence for implementation of comprehensive cardiometabolic care for men with prostate cancer. METHODS: This is a retrospective, descriptive study of patients with prostate cancer who were referred and evaluated in the Healthy Heart Program at MD Anderson Cancer Center, which was established to mitigate cardiometabolic risks in men with prostate cancer. Patients were seen by a cardiologist and exercise physiologist to evaluate and manage cardiometabolic risk factors, including blood pressure, cholesterol, blood glucose, tobacco use, and coronary artery disease, concurrent with management of their cancer by a medical oncologist. RESULTS: From December 2018 through October 2021, the Healthy Heart Program enrolled 55 men with prostate cancer, out of which 35 had biochemical, locoregional recurrence or distant metastases, while all received at least a single dose of a luteinizing hormone-releasing hormone (LHRH) analog. Ninety-three percent of men were overweight or obese, and 51% had an intermediate or high risk of atherosclerotic cardiovascular disease at 10 years based on the pooled cohort equation. Most men had an overlap of two or more cardiometabolic diseases (84%), and 25% had an overlap of at least 4 cardiometabolic diseases. Although uncontrolled hypertension and hyperlipidemia were common among the cohort (45% and 26%, respectively), only 29% of men followed up with the clinic. CONCLUSIONS: Men with prostate cancer have a high burden of concurrent cardiometabolic risk factors. At a tertiary cancer center, the Healthy Heart Program was implemented to address this need, yet the utility of the program was limited by poor follow-up possibly due to outside cardiometabolic care and inconvenient appointment logistics, a lack of cardiometabolic labs at the time of visits, and telemedicine visits.

Combination Treatment with Sipuleucel-T and Abiraterone Acetate or Enzalutamide for Metastatic Castration-Resistant Prostate Cancer: STAMP and STRIDE Trials.

PURPOSE: We present long-term outcomes from 2 randomized studies [STAMP (with abiraterone, NCT01487863) and STRIDE (with enzalutamide, NCT01981122)] that were performed to study the impact of sequential or concurrent administration of androgen receptor-targeting agents (ARTAs) on sipuleucel-T immune response and overall survival (OS) in metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: Sipuleucel-T was administered per current prescribing information. Results from STRIDE are presented together with updated STAMP results. Survival status of patients was updated using demographic information to query the National Death Index (NDI). Kaplan-Meier methodology was used to analyze survival. RESULTS: Updated data reduced patient censoring in each study compared with the original analyses; the 95% confidence intervals (CIs) for OS are now estimable. Updated median OS (95% CI) is 33.3 (24.1-40.7) months for STAMP and 32.5 (26.0-45.1) months for STRIDE. There was no notable impact on median OS [HR, 0.727 (0.458-1.155); P = 0.177, reference = STRIDE]. OS with sequential administration was similar to concurrent administration [NDI update: HR, 0.963 (0.639-1.453); P = 0.845, reference = concurrent arm]. Sipuleucel-T potency, measured as antigen-presenting cell (APC) activation, was higher in subsequent infusions compared with the first infusion. Humoral responses (IgG + IgM antibody titers) to PA2024 and prostatic acid phosphatase were significantly elevated versus baseline. No new safety signals were observed. CONCLUSIONS: Median OS was consistent regardless of whether the agents were administered sequentially or concurrently, including after NDI update. Results suggest that sipuleucel-T induces an immunologic prime-boost effect after initial sipuleucel-T exposure, even when combined with ARTAs.

Immune checkpoint therapy-current perspectives and future directions.

Immune checkpoint therapy (ICT) has dramatically altered clinical outcomes for cancer patients and conferred durable clinical benefits, including cure in a subset of patients. Varying response rates across tumor types and the need for predictive biomarkers to optimize patient selection to maximize efficacy and minimize toxicities prompted efforts to unravel immune and non-immune factors regulating the responses to ICT. This review highlights the biology of anti-tumor immunity underlying response and resistance to ICT, discusses efforts to address the current challenges with ICT, and outlines strategies to guide the development of subsequent clinical trials and combinatorial efforts with ICT.

Immune and pathologic responses in patients with localized prostate cancer who received daratumumab (anti-CD38) or edicotinib (CSF-1R inhibitor).

BACKGROUND: The prostate tumor microenvironment (TME) is immunosuppressive, with few effector T cells and enrichment of inhibitory immune populations, leading to limited responses to treatments such as immune checkpoint therapies (ICTs). The immune composition of the prostate TME differs across soft tissue and bone, the most common site of treatment-refractory metastasis. Understanding immunosuppressive mechanisms specific to prostate TMEs will enable rational immunotherapy strategies to generate effective antitumor immune responses. Daratumumab (anti-CD38 antibody) and edicotinib (colony-stimulating factor-1 receptor (CSF-1R) inhibitor) may alter the balance within the prostate TME to promote antitumor immune responses. HYPOTHESIS: Daratumumab or edicotinib will be safe and will alter the immune TME, leading to antitumor responses in localized prostate cancer. PATIENTS AND METHODS: In this presurgical study, patients with localized prostate cancer received 4 weekly doses of daratumumab or 4 weeks of daily edicotinib prior to radical prostatectomy (RP). Treated and untreated control (Gleason score ≥8 in prostate biopsy) prostatectomy specimens and patient-matched pre- and post-treatment peripheral blood mononuclear cells (PBMCs) and bone marrow samples were evaluated. The primary endpoint was incidence of adverse events (AEs). The secondary endpoint was pathologic complete remission (pCR) rate. RESULTS: Twenty-five patients were treated (daratumumab, n=15; edicotinib, n=10). All patients underwent RP without delays. Grade 3 treatment-related AEs with daratumumab occurred in 3 patients (12%), and no ≥grade 3 treatment-related AEs occurred with edicotinib. No changes in serum prostate-specific antigen (PSA) levels or pCRs were observed. Daratumumab led to a decreased frequency of CD38+ T cells, natural killer cells, and myeloid cells in prostate tumors, bone marrow, and PBMCs. There were no consistent changes in CSF-1R+ immune cells in prostate, bone marrow, or PBMCs with edicotinib. Neither treatment induced T cell infiltration into the prostate TME. CONCLUSIONS: Daratumumab and edicotinib treatment was safe and well-tolerated in patients with localized prostate cancer but did not induce pCRs. Decreases in CD38+ immune cells were observed in prostate tumors, bone marrow, and PBMCs with daratumumab, but changes in CSF-1R+ immune cells were not consistently observed with edicotinib. Neither myeloid-targeted agent alone was sufficient to generate antitumor responses in prostate cancer; thus, combinations with agents to induce T cell infiltration (eg, ICTs) will be needed to overcome the immunosuppressive prostate TME.

Anti-PD-L1 plus enzalutamide does not improve overall survival in prostate cancer.

The addition of atezolizumab (anti-PD-L1) to enzalutamide (androgen receptor antagonist) did not prolong survival in metastatic prostate cancer.1 Efficacy with immunotherapies in prostate cancer will require additional studies to elucidate and target mechanisms of resistance within the prostate tumor microenvironment.

A composite T cell biomarker in pre-treatment blood samples correlates with detection of immune-related adverse events.

Finding biomarkers for predicting anti-tumor responses and immune-related adverse events (irAEs) with immune checkpoint therapy remains a challenge. Lozano et al. have developed a composite biomarker score that includes the frequency of effector-memory CD4 T cells and TCR clonality of CD4 T cells in peripheral blood as a potentially predictive biomarker of irAEs.

Safety and preliminary immunogenicity of JNJ-64041809, a live-attenuated, double-deleted Listeria monocytogenes-based immunotherapy, in metastatic castration-resistant prostate cancer.

BACKGROUND: The safety and immunogenicity of JNJ-64041809 (JNJ-809), a live-attenuated, double-deleted Listeria monocytogenes (LADD Lm)-based immunotherapy targeting 4 relevant prostate cancer antigens, was evaluated in a phase 1 study in patients with metastatic castration-resistant prostate cancer (mCRPC). METHODS: Men with progressive mCRPC who had received ≥2 prior approved therapies were enrolled. Primary study objectives were to determine the recommended phase 2 dose (RP2D) and to evaluate the safety and immunogenicity of JNJ-809. RESULTS: A total of 26 patients received JNJ-809 (1 × 108 CFU (n = 6); 1 × 109 CFU (n = 20)). No dose-limiting toxicities were reported, and 1 × 109 CFU was selected as the RP2D. The most common adverse events (AEs) reported were chills (92%), pyrexia (81%), and fatigue (62%). The most frequent grade ≥3 AEs were lymphopenia (27%) and hypertension (23%). Serious AEs were reported in 27% of patients including 1 patient with grade 3 intestinal obstruction. JNJ-809 transiently induced peripheral cytokines, including interferon-γ, interleukin-10, and tumor necrosis factor-α. Of the 7 patients evaluable for T cell responses at the 1 × 109 CFU dose, evidence of post-treatment antigenic responses were observed in 6 to the Listeria antigen listeriolysin O and in 5 to ≥1 of the 4 encoded tumor antigens. Best overall response was stable disease in 13/25 response-evaluable patients. The study was terminated early as data collected were considered sufficient to evaluate safety and immunogenicity. CONCLUSIONS: JNJ-809 has manageable safety consistent with other LADD Lm-based therapies. Limited antigen-specific immune responses were observed, which did not translate into objective clinical responses.

Combined CTLA-4 and PD-L1 blockade in patients with chemotherapy-naïve metastatic castration-resistant prostate cancer is associated with increased myeloid and neutrophil immune subsets in the bone microenvironment.

BACKGROUND: Immune checkpoint therapy (ICT) has low response rates in patients with metastatic castration-resistant prostate cancer (mCRPC), in part due to few T cells in the tumor microenvironment (TME). Anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) promotes intratumoral T cell infiltration but induces upregulation of PD-1 and programmed death ligand-1 (PD-L1) within the prostate TME. Combined anti-CTLA-4 plus anti-PD-1 can partly overcome this adaptive resistance and was recently shown to augment responses in patients with mCRPC with measurable disease. Although bone is the most common site of metastasis in prostate cancer, patients with bone-predominant disease are frequently excluded from trials because they lack measurable disease, which limits assessment of disease progression and tissue sampling. We therefore designed this study to investigate combined ICT in mCRPC to bone. HYPOTHESIS: Combined anti-CTLA-4 (tremelimumab) plus anti-PD-L1 (durvalumab) is safe and well tolerated in patients with chemotherapy-naïve mCRPC to bone. PATIENTS AND METHODS: In this single-arm pilot study, men with chemotherapy-naïve mCRPC to bone received tremelimumab (75 mg intravenous) plus durvalumab (1500 mg intravenous) every 4 weeks (up to four doses), followed by durvalumab (1500 mg intravenous) maintenance every 4 weeks (up to nine doses). The primary endpoint was incidence of adverse events. Secondary endpoints included serum prostate-specific antigen (PSA), progression-free survival (PFS), radiographic PFS (rPFS), and maximal PSA decline. RESULTS: Twenty-six patients were treated between August 8, 2017 and March 28, 2019. Grade ≥3 treatment-related adverse events (TRAEs) occurred in 11 patients (42%), with no grade 4 or 5 events. TRAEs leading to discontinuation occurred in three patients (12%). PSA decline ≥50% occurred in three patients (12%). Six patients (24%) achieved stable disease for >6 months. At a median follow-up of 43.6 months, median rPFS was 3.7 months (95% CI: 1.9 to 5.7), and median overall survival was 28.1 months (95% CI: 14.5 to 37.3). Post-treatment evaluation of the bone microenvironment revealed transcriptional upregulation in myeloid and neutrophil immune subset signatures and increased expression of inhibitory immune checkpoints. CONCLUSIONS: Tremelimumab plus durvalumab was safe and well tolerated in patients with chemotherapy-naïve mCRPC to bone, with potential activity in a small number of patients as measured by rPFS. Combination of CTLA-4 and PD-L1 blockade with therapies targeting the myeloid compartment or other inhibitory immune receptors may be necessary to overcome mechanisms of resistance within prostate bone microenvironment. TRIAL REGISTRATION NUMBER: NCT03204812.

Abiraterone acetate plus prednisone in non-metastatic biochemically recurrent castration-naïve prostate cancer.

BACKGROUND: Intermittent androgen deprivation therapy (ADT) in biochemically recurrent castration-naïve prostate cancer is non-inferior to continuous therapy. We hypothesised that finite-duration abiraterone acetate plus prednisone (Abi +P) added to ADT will further reduce the duration of treatment exposure by prolonging time to prostate-specific antigen (PSA) recurrence without impacting eugonad state recovery. METHODS: This phase II, randomised, open-label trial enrolled patients with rising PSA ≥ 0.2 ng/ml after radical prostatectomy and/or a PSA ≥ 1 following radiotherapy. Patients were randomised 1:1 to receive Abi (1 g PO daily) + P (5 mg PO daily) + ADT or ADT alone for 8 months. The primary end-point was PSA-free survival difference at 1 year following completion of therapy. RESULTS: Between February 2013 and July 2016, 200 patients were enrolled. Of 100 patients randomised to each arm, 99 in the Abi +P arm and 98 in the ADT arm were evaluable. Median follow-up was 64.4 months. Median PSA-free survival was 27.0 months for the Abi +P-treated group versus 19.9 months for the ADT-treated group (hazard ratio [HR] 0.64, 95% confidence interval [CI] 0.47-0.87). The PSA-free survival at 1 year post-treatment completion was 98% for the Abi +P group and 88% for the ADT group. Median time to eugonad state was 13.1 months for the abiraterone-treated group and 12.8 months for the ADT-treated group. Median eugonad PSA-free survival was 12.5 months for the abiraterone-treated group versus 9.0 for the ADT-treated group (HR 0.72, 95% CI 0.53-0.98). There were no significant between-group differences in androgen deprivation-related adverse events. CONCLUSIONS: In men with biochemically recurrent prostate cancer following definitive treatment of the primary, finite duration treatment with ADT and Abi +P results in a significantly longer PSA relapse-free interval than treatment with ADT alone.

Evaluation of Technology-Enabled Monitoring of Patient-Reported Outcomes to Detect and Treat Toxic Effects Linked to Immune Checkpoint Inhibitors.

Importance: Immune checkpoint inhibitors can produce distinct toxic effects that require prompt recognition and timely management. Objective: To develop a technology-enabled, dynamically adaptive protocol that can provide the accurate information needed to inform specific remedies for immune toxic effects in patients treated with immune checkpoint inhibitors. Design, Setting, and Participants: An open-label cohort study was conducted at a single tertiary referral center from September 6, 2019, to September 3, 2020. The median follow-up duration was 63 (interquartile range, 35.5-122) days. Fifty patients with genitourinary cancers treated with immune checkpoint inhibitors were enrolled. Interventions: A fit-for-purpose electronic platform was developed to enable active patient and care team participation. A smartphone application downloaded onto patients' personal mobile devices prompted them to report their symptoms at least 3 times per week. The set of symptoms and associated queries were paired with alert thresholds for symptoms requiring clinical action. Main Outcomes and Measures: The primary end point of this interim analysis was feasibility, as measured by patient and care team adherence, and lack of increase in care team staffing. Operating characteristics were estimated for each symptom alert and used to dynamically adapt the alert thresholds to ensure sensitivity while reducing unnecessary alerts. Results: Of the 50 patients enrolled, 47 had at least 1 follow-up visit and were included in the analysis. Median age was 65 years (range, 37-86), 39 patients (83%) were men, and 39 patients (83%) had metastatic cancer, with the most common being urothelial cell carcinoma and renal cell carcinoma (22 [47%] patients each). After initial onboarding, no further care team training or additional care team staffing was required. Patients had a median study adherence rate of 74% (interquartile range, 60%-86%) and 73% of automated alerts were reviewed within 3 days by the clinic team. Symptoms with the highest positive predictive value for adverse events requiring acute intervention included dizziness (21%), nausea/vomiting (26%), and shortness of breath (14%). The symptoms most likely to result in unnecessary alerts were arthralgia and myalgia, fatigue, and cough. Conclusions and Relevance: The findings of this cohort study suggest an acceptable and fiscally sound method can be developed to create a dynamic learning system to detect and manage immune-related toxic effects.

Durable responses in patients with genitourinary cancers following immune checkpoint therapy rechallenge after moderate-to-severe immune-related adverse events.

BACKGROUND: Immune checkpoint therapy (ICT) prolongs survival in subsets of patients with cancer but can also trigger immune-related adverse events (irAEs) requiring treatment discontinuation. Recent studies have investigated safety of ICT rechallenge after irAEs, and evidence suggests that rechallenge may be associated with improved antitumor responses. However, data are limited on response duration after ICT rechallenge, particularly after severe irAEs. OBJECTIVE: To evaluate safety and efficacy of ICT rechallenge after moderate-to-severe irAEs in patients with renal cell carcinoma (RCC), urothelial carcinoma (UC), and prostate cancer. METHODS: In this retrospective cohort study, medical records from September 25, 2013, to June 1, 2020, for patients with genitourinary (GU) cancers at MD Anderson Cancer Center who were rechallenged with the same or different ICT following irAEs were reviewed. Demographics, ICT exposure, irAEs (grade and treatment), ICT discontinuation or rechallenge, rates of subsequent irAEs (new or recurrent) and antitumor activity (objective response rates and response duration) were reviewed. RESULTS: Sixty-one patients with RCC, UC, and prostate cancer were rechallenged with ICT after experiencing 105 total irAEs. Objective response rates after rechallenge, that is, upgrade in response, were 14% in RCC (4/28), 21% in UC (3/14), and 0% in prostate cancer. All seven patients who achieved upgrade in response had initial grade 2 or 3 irAEs. Responses were durable among these seven patients, with median radiographic progression-free survival not reached (range: 3.7-66.4 months) as of the March 8, 2021, data cut-off (median follow-up 40.9 months (95% CI 35.3 to 46.5)). All achieved complete response except one patient who was lost to follow-up. The rate of subsequent grade 3 or 4 irAEs after rechallenge was 30%, with no fatal irAEs. The rate of recrudescence of the same irAE was 26% (16/61). 54% of patients received corticosteroids (33/61), and 21% received targeted immunosuppression (13/61) for the initial irAEs. CONCLUSIONS AND RELEVANCE: ICT rechallenge after moderate-to-severe irAEs was associated with deep and durable responses in a subset of patients with RCC and UC, with acceptable safety and no fatal events. Strategies to enable ICT resumption after moderate-to-severe irAEs, such targeted immunosuppression, warrant further study.

Phase 1b study of pegylated arginine deiminase (ADI-PEG 20) plus Pembrolizumab in advanced solid cancers.

Background: Pegylated arginine deiminase (ADI-PEG 20) is a metabolism-based strategy that depletes arginine, resulting in tumoral stress and cytotoxicity. Preclinically, ADI-PEG 20 modulates T-cell activity and enhances the therapeutic efficacy of programmed death-1 (PD-1) inhibition. Methods: A phase 1b study, including a dose-escalation cohort and an expansion cohort, was undertaken to explore the effects of ADI-PEG 20 in combination with pembrolizumab, an anti-PD-1 antibody, for safety, pharmacodynamics, and response. CD3 levels and programmed death-ligand 1 (PD-L1) expression were assessed in paired biopsies collected prior to and after ADI-PEG 20 treatment but before pembrolizumab. Results: Twenty-five patients, nine in the dose-escalation cohort and sixteen in the expansion cohort, were recruited. Treatment was feasible with adverse events consistent with those known for each agent, except for Grade 3/4 neutropenia which was higher than expected, occurring in 10/25 (40%) patients. Mean arginine levels were suppressed for 1-3 weeks, but increased gradually. CD3+ T cells increased in 10/12 (83.3%) subjects following ADI-PEG 20 treatment, including in three partial responders (p = .02). PD-L1 expression was low and increased in 3/10 (30%) of subjects. Partial responses occurred in 6/25 (24%) heavily pretreated patients, in both argininosuccinate synthetase 1 proficient and deficient subjects. Conclusions: The immunometabolic combination was safe with the caveat that the incidence of neutropenia might be increased compared with either agent alone. ADI-PEG 20 treatment increased T cell infiltration in the low PD-L1 tumor microenvironment. The recommended phase 2 doses are 36 mg/m2 weekly for ADI-PEG 20 and 200 mg every 3 weeks for pembrolizumab.

Immune checkpoint inhibitor myocarditis: elucidating the spectrum of disease through endomyocardial biopsy.

AIMS: Although immune checkpoint inhibitor (ICI) myocarditis carries a high reported mortality, increasing reports of smoldering myocarditis suggest a clinical spectrum of disease. Endomyocardial biopsy (EMB) remains the gold standard for diagnosis of ICI myocarditis, but different pathologic diagnostic criteria exist. The objective of this study was to classify the spectrum of ICI myocarditis and myocardial inflammation by pathology findings on EMB and correlate this with clinical outcomes. METHODS AND RESULTS: All patients who had EMB at MD Anderson Cancer Center between January 2018 and August 2019 for suspected ICI myocarditis were retrospectively reviewed. A grading system (Grades 0-2) based on the degree of inflammatory infiltrate was developed by pathologists. Cardiovascular outcomes and treatment were compared between grades of pathology. We identified 28 patients who had EMB for suspected ICI myocarditis, of which 18 were positive for myocarditis/inflammation. There were four deaths (two in Grade 2 and two in Grade 1), but only one was attributable to myocarditis. Grade 2 patients had no myocarditis-associated deaths despite having the highest troponin T values (median 2063 pg/mL). Four patients with Grade 1 myocardial inflammation continued ICI without any immunomodulation, and all were alive without adverse cardiovascular events at follow-up. CONCLUSION: We defined an EMB grading system for ICI myocarditis encompassing a spectrum of histologic findings of inflammatory infiltrates. A subset of low-grade myocardial inflammation patients were able to continue ICI without immunosuppressive therapy. Further studies are needed to identify low-risk patients who can be safely treated with ICI.

Immune checkpoint inhibitor related hypophysitis: diagnostic criteria and recovery patterns.

Data on the diagnosis, natural course and management of immune checkpoint inhibitor (ICI)-related hypophysitis (irH) are limited. We propose this study to validate the diagnostic criteria, describe characteristics and hormonal recovery and investigate factors associated with the occurrence and recovery of irH. A retrospective study including patients with suspected irH at the University of Texas MD Anderson Cancer Center from 5/2003 to 8/2017 was conducted. IrH was defined as: (1) ACTH or TSH deficiency plus MRI changes or (2) ACTH and TSH deficiencies plus headache/fatigue in the absence of MRI findings. We found that of 83 patients followed for a median of 1.75 years (range 0.6-3), the proposed criteria used at initial evaluation accurately identified 61/62 (98%) irH cases. In the irH group (n = 62), the most common presentation was headache (60%), fatigue (66%), central hypothyroidism (94%), central adrenal insufficiency (69%) and MRI changes (77%). Compared with non-ipilimumab (ipi) regimens, ipi has a stronger association with irH occurrence (P = 0.004) and a shorter time to irH development (P < 0.01). Thyroid, gonadal and adrenal axis recovery occurred in 24, 58 and 0% patients, respectively. High-dose steroids (HDS) or ICI discontinuation was not associated with hormonal recovery. In the non-irH group (n = 19), one patient had isolated central hypothyroidism and six had isolated central adrenal insufficiency. All remained on hormone therapy at the last follow-up. We propose a strict definition of irH that identifies the vast majority of patients. HDS and ICI discontinuation is not always beneficial. Long-term follow-up to assess recovery is needed.

The Next Decade of Immune Checkpoint Therapy.

Immune checkpoint therapy (ICT) can provide durable clinical responses and improve overall survival. However, only subsets of patients with specific tumor types respond to ICT. Thus, significant challenges remain, including understanding pathways of resistance, optimizing patient selection, improving management of immune-related adverse events, and identifying rational therapeutic combinations. These challenges will need a focused approach encompassing both clinical and basic research, with the integration of reverse translational studies. This integrated approach will lead to identification of potential targets for subsequent clinical trials, which will guide decisions as we develop novel combination strategies to maximize efficacy and minimize toxicities for patients. SIGNIFICANCE: ICTs induce durable antitumor responses for subsets of patients with cancer. Recent evidence suggests that rational combinatorial strategies can improve response by overcoming primary and adaptive resistance mechanisms, although these may carry an increased risk of immune-mediated toxicities. This review surveys the current understanding of mechanisms of response and resistance to ICTs and active areas of investigation, and proposes a path forward to improving efficacy and minimizing toxicities through better patient selection and rational combinations.