A Phase II Window of Opportunity Study of Neoadjuvant PD-L1 versus PD-L1 plus CTLA-4 Blockade for Patients with Malignant Pleural Mesothelioma.

PURPOSE: We report the results of a phase II, randomized, window-of-opportunity trial of neoadjuvant durvalumab versus durvalumab plus tremelimumab followed by surgery in patients with resectable malignant pleural mesothelioma (MPM; NCT02592551). PATIENTS AND METHODS: The primary objective was alteration of the intratumoral CD8/regulatory T cell (Treg) ratio after combination immune checkpoint blockade (ICB) therapy. Secondary and exploratory objectives included other changes in the tumor microenvironment, survival, safety, tumor pathologic response (PR), and systemic immune responses. RESULTS: Nine patients received monotherapy and 11 received combination therapy. Seventeen of the 20 patients (85%) receiving ICB underwent planned thoracotomy. Both ICB regimens induced CD8 T-cell infiltration into MPM tumors but did not alter CD8/Treg ratios. At 34.1 months follow-up, patients receiving combination ICB had longer median overall survival (not reached) compared with those receiving monotherapy (14.0 months). Grade ≥3 immunotoxicity occurred in 8% of patients in the monotherapy group and 27% of patients in the combination group. Tumor PR occurred in 6 of 17 patients receiving ICB and thoracotomy (35.3%), among which major PR (>90% tumor regression) occurred in 2 (11.8%). Single-cell profiling of tumor, blood, and bone marrow revealed that combination ICB remodeled the immune contexture of MPM tumors; mobilized CD57+ effector memory T cells from the bone marrow to the circulation; and increased the formation of tertiary lymphoid structures in MPM tumors that were rich in CD57+ T cells. CONCLUSIONS: These data indicate that neoadjuvant durvalumab plus tremelimumab orchestrates de novo systemic immune responses that extend to the tumor microenvironment and correlate with favorable clinical outcomes.

Persistent ethnicity-associated disparity in anti-tumor effectiveness of immune checkpoint inhibitors despite equal access.

We reviewed response to immune checkpoint inhibitors (ICI) of 207 patients with diagnoses of lung or head and neck cancer treated with chemotherapy/ICI combination therapy and ICI monotherapy between 2015 and 2020 at one of three clinical pavilions associated with the Dan L. Duncan Comprehensive Cancer Center at Baylor College of Medicine. Two of these pavilions (Harris Health System and the Michael E. DeBakey Veterans Affairs Medical Center) serve large minority populations and provide equal access to care regardless of means. 174 patients had a diagnosis of lung cancer (non-small cell or small cell) and 33 had a diagnosis of head and neck squamous cell carcinoma (HNSCC). 38% self-identified as Black, 45% as non-Hispanic White, and 18% as Hispanic. The objective response rate (ORR) was similar for lung cancer (35.057%) and HNSCC patients (30.3%) (p=0.894). The ORR for Hispanic and Black patients was lower compared to non-Hispanic White patients (H 27.0%, B 32.5%, W 38.7%; H vs. W p=0.209; B vs. W p=0.398). When considering only patients treated with ICI monotherapy, the ORR for Hispanic patients dropped further to 20.7% while the ORR of Black and non-Hispanic White patients remained about the same (B 29.3% and W 35.9%, H vs. W p=0.133; B vs. W p=0.419). Immune related adverse events were the lowest in the Hispanic population occurring in only 30% of patients compared to 40% of patients in the Black cohort and 50% of the non-Hispanic White cohorts.

Therapeutic Targeting of Macrophage Plasticity Remodels the Tumor-Immune Microenvironment.

SIGNIFICANCE: Comprehensive single-cell proteomics analyses of lung adenocarcinoma progression reveal the role of tumor-associated macrophages in resistance to PD-1 blockade therapy. See related commentary by Lee et al., p. 2515.

Inhibition of Cyclin Dependent Kinase 4/6 Overcomes Primary Resistance to Programmed Cell Death 1 Blockade in Malignant Mesothelioma.

BACKGROUND: Despite the profound number of malignant pleural mesothelioma (MPM) patients now treated with programmed cell death 1 (PD-1) blockade, insight into the underpinnings of rational therapeutic strategies to treat resistance to checkpoint immunotherapy remains unrealized. Our objective was to develop a novel therapeutic approach to overcome primary resistance to PD-1 blockade in MPM. METHODS: We generated a transcriptome signature of resistance to PD-1 blockade in MPM patients treated with nivolumab (4 responders and 4 nonresponders). We used The Cancer Genome Atlas MPM cohort (n = 73) to determine what genomic alterations were associated with the resistance signature. We tested whether regulation of identified molecules could overcome resistance to PD-1 blockade in an immunocompetent mouse malignant mesothelioma model. RESULTS: Immunogenomic analysis by applying our anti-PD-1 resistance signature to The Cancer Genome Atlas cohort revealed that deletion of cyclin dependent kinase inhibitor 2A (CDKN2A) was highly associated with primary resistance to PD-1 blockade. Under the hypothesis that resistance to PD-1 blockade can be overcome by cyclin dependent kinase 4/6 (CDK4/6) inhibition, we tested whether CDK4/6 inhibitors could overcome resistance to PD-1 blockade in subcutaneous tumors derived from Cdkn2a-/- AB1 malignant mesothelioma cells, which were resistant to PD-1 blockade. The combination of daily oral administration of CDK4/6 inhibitors (abemaciclib or palbociclib) and intraperitoneal anti-PD-1 treatment markedly suppressed tumor growth compared with anti-PD-1 or CDK4/6 inhibitor alone. CONCLUSIONS: We identified a therapeutic target, CDK4/6, to overcome primary resistance to PD-1 blockade through comprehensive immunogenomic approaches. These data provide a rationale for undertaking clinical trials of CDK4/6 inhibitors in more than 40% of patients with MPM who demonstrate loss of CDKN2A.

What risk factors for sudden infant death syndrome are preterm and term medically complex infants exposed to at home?

OBJECTIVES: Risk factors for sudden infant death syndrome include premature birth, maternal smoking, prone or side sleeping position, sleeping with blankets, sharing a sleeping surface with an adult, and sleeping without an adult in the room. In this study, we compare parents' responses on sleep patterns in premature and term infants with medical complexity. METHODS: Parents of children enrolled in the Canadian Respiratory Syncytial Virus Evaluation Study of Palivizumab were phoned monthly regarding their child's health status until the end of each respiratory syncytial virus season. Baseline data were obtained on patient demographics, medical history, and neonatal course. Responses on adherence to safe sleep recommendations were recorded as part of the assessment. RESULTS: A total of 2,526 preterms and 670 term infants with medical complexity were enrolled. Statistically significant differences were found in maternal smoking rates between the two groups: 13.3% (preterm); 9.3% (term) infants (χ 2=8.1, df=1, P=0.004) and with respect to toys in the crib: 12.3% (term) versus 5.8% preterms (χ 2=24.5, df=1, P<0.0005). Preterm infants were also significantly more likely to be placed prone to sleep (8.8%), compared with term infants (3.3%), (χ 2=18.1, df=1, P<0.0005). CONCLUSION: All the infants in this study had frequent medical contacts. There is a greater prevalence of some risk factors for sudden infant death syndrome in preterm infants compared to term infants with medical complexity. Specific educational interventions for vulnerable infants may be necessary.

Hyperacute toxicity with combination ipilimumab and anti-PD1 immunotherapy.

BACKGROUND: Combination ipilimumab and nivolumab is approved for several malignancies. Toxicity most often occurs 6-10 weeks into treatment. Whether very early toxicity is harder to manage or influences efficacy is unknown. METHODS: Consecutive metastatic melanoma patients who developed hyperacute toxicity, defined as Grade 2+ irAE within 21 days of receiving ipilimumab + anti-PD-1 were retrospectively identified from nine centres. RESULTS: A total of 82 patients developed hyperacute toxicity (estimated incidence 9%), at a median 10 days (range 1-21). Toxicities included colitis (N = 23), rash (17), hepatitis (9), endocrine (9), pneumonitis (6) and neurotoxicity (4) and were G2 (38%), G3 (52%), G4 (6%) and G5 (2% myocarditis). Fifty-nine percent required treatment beyond oral steroids, including IV steroids (28%), infliximab and other immunosuppression (30%). A total of 29% patients developed an additional hyperacute toxicity and 26% another toxicity >21 days after treatment commencement but before further immunotherapy. The objective response rate (ORR) was 54%, and after a median 11.6 mo follow-up, median PFS was 7.4 mo. Increasing levels of immunosuppression was associated with a reduced PFS (12-month PFS 62% no immunosuppression versus 49% oral steroids versus 33% IV steroids versus 20% further immunosuppressants, p = 0.006). There was no significant difference in ORR or PFS by duration of immunosuppression. CONCLUSIONS: Hyperacute toxicities from combination immunotherapy have a wide spectrum and can be severe. Many patients require significant immunosuppression for prolonged durations and remain at risk of further severe toxicity. Melanoma outcomes in such patients appear similar to those of trial populations, although greater immunosuppression requirements may be associated with inferior outcomes.

Immune checkpoint inhibitor associated reactivation of primary membranous nephropathy responsive to rituximab.

The same mechanisms that mediate antitumor immunity from checkpoint inhibitors (CPIs) can also lead to unintended targeting of normal tissues, characterized as immune-related adverse events (irAEs). Those with pre-existing autoimmune disease are believed to be particularly vulnerable for exacerbating underlying autoimmunity or inducing severe irAEs. We report the first case of CPI-associated reactivation of primary membranous nephropathy (MN) in a patient with pleural mesothelioma responding to immunotherapy. Due to its specificity in targeting B-lymphocytes, rituximab was used to treat primary MN with the expectation that this would not interfere with the benefits gained from T cell-mediated antitumor immunity. Rituximab was effective in treating CPI-associated reactivation of MN, and the patient was successfully rechallenged with nivolumab and maintained stable kidney function and sustained clinical antitumor effect. While exacerbation of pre-existing autoimmune diseases from CPIs is common, therapy for autoimmune reactivation can be rationally directed by an understanding of the immunosuppressive mechanism with goals of cancer treatment.

Mucosal inflammation predicts response to systemic steroids in immune checkpoint inhibitor colitis.

BACKGROUND: Immune-related colitis is a common, often serious complication of immune checkpoint inhibition (ICI). Although endoscopy is not strictly recommended for any grade of diarrhea/colitis, emerging evidence suggests that endoscopic evaluation may have important therapeutic implications. In this retrospective study, we sought to comprehensively characterize the clinical and histologic features of ICI-induced colitis with a specific focus on evaluating the prognostic role of endoscopy. METHODS: Data were collected from the medical records of 130 patients with confirmed ICI-induced colitis. In a subset of patients (n=44) with endoscopic and pathologic data, endoscopic data were scored using the Mayo Endoscopic Score (MES) with scores ranging from 0 (no inflammation) to 3 (colonic ulceration). The impact of infliximab on antitumor outcomes was evaluated using progression-free survival (PFS) and overall survival (OS). RESULTS: We identified 130 patients with ICI-induced colitis across two institutions. All patients were treated with corticosteroids. Additional and/or alternative immunosuppression was employed in 59 cases, with 52 patients (42%) requiring at least one infusion of infliximab 5 mg/kg. Endoscopic assessment with biopsy was performed in 123 cases of suspected colitis (95%), with 44 cases available for MES tabulation. Presence of ulceration (MES 3) was associated with use of infliximab (p=0.008) and MES was significantly higher in patients who received infliximab compared with those who did not (p=0.003) with a median score of 2.5; conversely, those with an MES of zero rarely required secondary immunosuppression. Notably, symptoms of colitis based on Common Terminology Criteria for Adverse Events grade had no association with endoscopic findings based on MES classification. After adjustment for baseline patient and disease characteristics, there was no significant difference in steroid duration or cancer-related outcomes in patients treated with infliximab. CONCLUSIONS: In our study, we demonstrate the association of endoscopic features, specifically the MES, with immunosuppressive needs. Importantly, we also show that MES was not related to severity of patient symptoms. The data suggest that endoscopic features can guide clinical decision-making better than patient symptoms, both identifying high-risk patients who will require infliximab and those who are likely to respond to initial corticosteroids.

The Impact of Nonsteroidal Anti-Inflammatory Drugs, Beta Blockers, and Metformin on the Efficacy of Anti-PD-1 Therapy in Advanced Melanoma.

Anti-programmed cell death protein-1 (anti-PD-1) therapy has greatly improved outcomes of patients with melanoma; however, many fail to respond. Although preclinical studies suggest a potentially synergistic relationship with anti-PD-1 therapy and certain concurrent medications, their clinical role remains unclear. Here, we retrospectively evaluated the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and other drugs in 330 patients with melanoma treated with anti-PD-1 therapy from four academic centers. In the cohort, 37% of patients used NSAIDs including aspirin (acetylsalicylic acid; ASA; 47%), cyclooxygenase (COX)-2 inhibitors (2%), and non-ASA/nonselective COX inhibitor NSAIDs (59%). The objective response rates (ORRs) were similar in patients with NSAID (43.4%) and no NSAID (41.3%) use with no significant difference in overall suvival (OS). There was a trend toward improved progression-free survival (PFS) in patients who took NSAIDs (median PFS: 8.5 vs. 5.2 months; p = .054). Most patients (71.3%) took NSAIDs once daily or as needed. Multivariate analysis did not reveal an association with NSAID use with ORR, PFS, or OS. Concurrent use of metformin or beta blockers did not affect ORR, PFS, or OS. Our study found no conclusive association of concurrent NSAID or other medication use with improved outcomes in patients with melanoma treated with anti-PD-1 therapy. Larger and more systematic analysis is required to confirm these findings.

Predictors of benefits from frontline chemoimmunotherapy in stage IV non-small-cell lung cancer: a meta-analysis.

Background: Immune checkpoint inhibitors (ICIs) have dramatically expanded the therapeutic landscape of non-small-cell lung cancer (NSCLC). In a previous study, gender, smoking history, and PD-L1 status were found to influence the efficacy of single-agent ICI in NSCLC. This meta-analysis evaluated the clinical and molecular factors that could predict a benefit from adding ICIs to first-line chemotherapy in metastatic NSCLC. Patients and Methods: The pooled hazard ratio (HR) of progression-free survival (PFS) and overall survival (OS) among the selected subgroups were analyzed using the random effects model. The correlation between PD-L1 expression and outcome was analyzed by meta-regression. Results: Seven phase III randomized controlled trials comparing chemo-immunotherapy (CIT) with chemotherapy in untreated stage 4 NSCLC were included. CIT evenly improved PFS irrespective of age, gender, histology, smoking history, and performance status. Among patients with baseline hepatic metastasis treated with Atezolizumab-containing CIT, PFS improvement was only detected with the addition of Bevacizumab. Whereas patients with EGFR/ALK-driven cancer exhibited greater PFS with the addition of ICI to a Bevacizumab (BEV)-based regimen, the derived benefit was no longer statistically significant among those treated with non-BEV-based regimens. Although the superior PFS conferred by CIT was noticeable across all PD-L1 expression subgroups, this benefit correlated with PD-L1 level and was more pronounced in the "PD-L1 high" cohort. Except for patients harboring EGFR/ALK aberrations or squamous histology, CIT consistently improved OS across the other selected subgroups. Conclusions: The survival advantage associated with first-line CIT in metastatic NSCLC was observed in different patient populations, including those for which single-agent ICI has marginal therapeutic benefit. Our findings support the role of chemotherapy with or without VEGF blockade as enhancers of ICI activity in NSCLC.

Anti-PD-1-Induced Pneumonitis Is Associated with Persistent Imaging Abnormalities in Melanoma Patients.

Pneumonitis may complicate anti-programmed death-1 (PD-1) therapy, although symptoms usually resolve with steroids. The long-term effects on respiratory function, however, are not well defined. We screened melanoma patients treated with anti-PD-1, with and without ipilimumab (anti-CTLA-4), and identified 31 patients with pneumonitis. Median time to radiographic findings was 4.8 months. Twenty-three patients (74%) presented with respiratory symptoms, whereas 8 (26%) were asymptomatic, and 11 (35%) were hospitalized. With 22.1 months median follow-up, 27 patients (87%) had resolution of symptoms, whereas 4 had persistent cough, dyspnea, and/or wheezing. By contrast, the rate of radiographic resolution was lower: Only 11 (35%) had complete radiographic resolution, whereas 14 (45%) had improvement of pneumonitis with persistent scarring or opacities, and 6 (19%) had persistent or worsened ground-glass opacities and/or nodular densities. Persistence (vs. resolution) of radiographic findings was associated with older age and initial need for steroids but not with need for hospitalization, timing of onset, or treatment regimen (combination vs. monotherapy). Among patients with serial pulmonary function tests, lung function improved with time. Although symptoms of anti-PD-1-induced pneumonitis resolved quickly, scarring or inflammation frequently persisted on computerized tomography. Therefore, further study of subclinical pulmonary effects of anti-PD-1 is needed.

A case report of clonal EBV-like memory CD4+ T cell activation in fatal checkpoint inhibitor-induced encephalitis.

Checkpoint inhibitors produce durable responses in numerous metastatic cancers, but immune-related adverse events (irAEs) complicate and limit their benefit. IrAEs can affect organ systems idiosyncratically; presentations range from mild and self-limited to fulminant and fatal. The molecular mechanisms underlying irAEs are poorly understood. Here, we report a fatal case of encephalitis arising during anti-programmed cell death receptor 1 therapy in a patient with metastatic melanoma. Histologic analyses revealed robust T cell infiltration and prominent programmed death ligand 1 expression. We identified 209 reported cases in global pharmacovigilance databases (across multiple cancer types) of encephalitis associated with checkpoint inhibitor regimens, with a 19% fatality rate. We performed further analyses from the index case and two additional cases to shed light on this recurrent and fulminant irAE. Spatial and multi-omic analyses pinpointed activated memory CD4+ T cells as highly enriched in the inflamed, affected region. We identified a highly oligoclonal T cell receptor repertoire, which we localized to activated memory cytotoxic (CD45RO+GZMB+Ki67+) CD4 cells. We also identified Epstein-Barr virus-specific T cell receptors and EBV+ lymphocytes in the affected region, which we speculate contributed to neural inflammation in the index case. Collectively, the three cases studied here identify CD4+ and CD8+ T cells as culprits of checkpoint inhibitor-associated immune encephalitis.

Correlates of response and outcomes with talimogene laherperpvec.

BACKGROUND AND OBJECTIVES: Patients with in-transit or limited cutaneous metastatic melanoma may benefit from intralesional injections with talimogene laherparepvec (TVEC), a modified oncolytic herpesvirus. However, its use in patients with adverse prognostic scores in a real-life clinical setting has not been studied. METHODS: We performed a two-center retrospective analysis of 40 patients with metastatic melanoma treated with TVEC from 2015-2017. Demographics, overall response, and survival after therapy were noted. RESULTS: Overall, there was a durable response rate of 40%; median progression-free survival (PFS) was 10.5 months and median overall survival (OS) was not reached. Bulky disease was associated with decreased OS (15.7 months vs not reached, P < .05) and mPFS (2.3 months vs not reached, P < .05), when compared with smaller tumors. Poor performance status (ECOG 2-3) was associated with worse OS (10.2 months vs not reached, P < .05) and PFS (2.1 months vs not reached, P < .05) compared to patients with ECOG 0-1. There was no difference in the outcomes with age greater than 75 or with prior therapies. Adverse events were relatively tolerable. CONCLUSIONS: These findings demonstrate that TVEC is an effective and safe treatment for metastatic melanoma in a real-life clinical setting, and suggest parameters to aid in appropriate therapy selection for optimal response.

Clinical Correlates of Response to Anti-PD-1-based Therapy in Patients With Metastatic Melanoma.

Anti-PD-1 agents, alone or in combination with ipilimumab, produce durable responses in some melanoma patients. Tumor features that correlate with response are not well defined. We collected clinical data from metastatic melanoma patients treated at 2 centers who received anti-PD-1 (n=303) or anti-PD-1+ipilimumab (n=57). We correlated number of metastases, diameter of largest tumor (tumor bulk), and organ involvement with response rate (RR), progression-free survival (PFS), and overall survival (OS). Patients with diameter of largest tumor ≤2 cm had a 53% RR, whereas those with largest tumor >2 cm had a 38% RR (P=0.009). Those with liver metastases had lower RR (25% vs. 43%; P=0.002). RR to anti-PD-1 was greater in patients with ≤10 metastases compared with those with >10 (39% vs. 27%; P=0.027). In multivariable analyses, size of the largest tumor was independently associated with PFS (P=0.0005), OS (P<0.0001), and RR (P=0.02), whereas AJCC stage, lactate dehydrogenase, liver metastases, ECOG performance status, number of metastases, and prior therapies were not. In patients treated with anti-PD-1+ipilimumab, however, tumor bulk was not associated with outcomes, although number of metastases was associated with PFS (P=0.035) and RR (P=0.009) but not OS. Pathologic analysis did not reveal differences in T-cell infiltration in bulky versus small tumors. Tumor bulk, defined by diameter of largest tumor, was strongly and independently associated with clinical outcomes in anti-PD-1 but not in anti-PD-1+ipilimumab. In conjunction with molecular biomarkers, clinical predictors may help guide selection of immunotherapy agents.

Tolerance and efficacy of BRAF plus MEK inhibition in patients with melanoma who previously have received programmed cell death protein 1-based therapy.

BACKGROUND: Combined BRAF and MEK inhibition (BRAF-MEK) is a standard therapy for patients with BRAF V600-mutant melanoma, but to the authors' knowledge, the tolerance, adverse event (AE) profile, and efficacy have not been well defined in the post-programmed cell death protein 1 (PD-1) setting. METHODS: Patients with BRAF V600-mutant melanoma who received combined BRAF-MEK after prior PD-1-based therapy were assembled from 4 tertiary care centers in the United States and Australia. Dose modification was defined as a treatment break, dose reduction, or intermittent dosing. Rates of hospitalization and discontinuation due to AEs were collected, and overall survival (OS) was calculated using Kaplan-Meier methods from the time of the initiation of BRAF-MEK therapy. RESULTS: A total of 78 patients were identified as having received a BRAF-MEK regimen at a median of 34 days after the last dose of PD-1-based therapy. The majority of patients (86%) received the combination of dabrafenib and trametinib. Approximately 80% of patients had American Joint Committee on Cancer M1c or M1d disease. Sixty-five regimens (83%) had ≥1 dose modification. The median time to the first dose modification was 14 days; 86% occurred within 90 days and 71% involved pyrexia. Dose modifications were more common in patients receiving BRAF-MEK <90 days after the last dose of PD-1 and who were not receiving steroids. Of the dose modifications, 25 (31%) led to an AE-related hospitalization. Among 55 BRAF-naive patients, the median time receiving BRAF-MEK therapy was 5.8 months and the median OS was 15.6 months. CONCLUSIONS: The majority of patients receiving BRAF-MEK inhibition after PD-1 therapy require dose interruptions, and a significant minority require hospitalization for AEs. In this higher risk population, the median time receiving therapy and OS may be inferior to those presented in published phase 3 trials.

Clinical characterization of colitis arising from anti-PD-1 based therapy.

Colitis is a frequent, clinically-significant immune-related adverse event caused by anti-programmed death-1 (PD-1). The clinical features, timing, and management of colitis with anti-PD-1-based regimens are not well-characterized. Patients with advanced melanoma that received either anti-PD-1 monotherapy ("monotherapy") or combined with ipilimumab ("combination therapy") were screened from 8 academic medical centers, to identify those with clinically-relevant colitis (colitis requiring systemic steroids). Of 1261 patients who received anti-PD-1-based therapy, 109 experienced colitis. The incidence was 3.2% (30/937) and 24.4% (79/324) in the monotherapy and combination therapy cohorts, respectively. Patients with colitis from combination therapy had significantly earlier symptom onset (7.2 weeks vs 25.4 weeks, p < 0.0001), received higher steroid doses (median prednisone equivalent 1.5 mg/kg vs 1.0 mg/kg, p = 0.0015) and experienced longer steroid tapers (median 6.0 vs 4.0 weeks, p = 0.0065) compared to monotherapy. Infliximab use and steroid-dose escalation occurred more frequently in the combination therapy cohort compared to monotherapy. Nearly all patients had resolution of their symptoms although one patient died from complications. Anti-PD-1 associated colitis has a variable clinical presentation, and is more frequent and severe when associated with combination therapy. This variability in checkpoint-inhibitor associated colitis suggests that further optimization of treatment algorithms is needed.

Tumor-specific MHC-II expression drives a unique pattern of resistance to immunotherapy via LAG-3/FCRL6 engagement.

Immunotherapies targeting the PD-1 pathway produce durable responses in many cancers, but the tumor-intrinsic factors governing response and resistance are largely unknown. MHC-II expression on tumor cells can predict response to anti-PD-1 therapy. We therefore sought to determine how MHC-II expression by tumor cells promotes PD-1 dependency. Using transcriptional profiling of anti-PD-1-treated patients, we identified unique patterns of immune activation in MHC-II+ tumors. In patients and preclinical models, MHC-II+ tumors recruited CD4+ T cells and developed dependency on PD-1 as well as Lag-3 (an MHC-II inhibitory receptor), which was upregulated in MHC-II+ tumors at acquired resistance to anti-PD-1. Finally, we identify enhanced expression of FCRL6, another MHC-II receptor expressed on NK and T cells, in the microenvironment of MHC-II+ tumors. We ascribe this to what we believe to be a novel inhibitory function of FCRL6 engagement, identifying it as an immunotherapy target. These data suggest a MHC-II-mediated context-dependent mechanism of adaptive resistance to PD-1-targeting immunotherapy.

Fatal Toxic Effects Associated With Immune Checkpoint Inhibitors: A Systematic Review and Meta-analysis.

Importance: Immune checkpoint inhibitors (ICIs) are now a mainstay of cancer treatment. Although rare, fulminant and fatal toxic effects may complicate these otherwise transformative therapies; characterizing these events requires integration of global data. Objective: To determine the spectrum, timing, and clinical features of fatal ICI-associated toxic effects. Design, Setting, and Participants: We retrospectively queried a World Health Organization (WHO) pharmacovigilance database (Vigilyze) comprising more than 16 000 000 adverse drug reactions, and records from 7 academic centers. We performed a meta-analysis of published trials of anti-programmed death-1/ligand-1 (PD-1/PD-L1) and anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) to evaluate their incidence using data from large academic medical centers, global WHO pharmacovigilance data, and all published ICI clinical trials of patients with cancer treated with ICIs internationally. Exposures: Anti-CTLA-4 (ipilimumab or tremelimumab), anti-PD-1 (nivolumab, pembrolizumab), or anti-PD-L1 (atezolizumab, avelumab, durvalumab). Main Outcomes and Measures: Timing, spectrum, outcomes, and incidence of ICI-associated toxic effects. Results: Internationally, 613 fatal ICI toxic events were reported from 2009 through January 2018 in Vigilyze. The spectrum differed widely between regimens: in a total of 193 anti-CTLA-4 deaths, most were usually from colitis (135 [70%]), whereas anti-PD-1/PD-L1-related fatalities were often from pneumonitis (333 [35%]), hepatitis (115 [22%]), and neurotoxic effects (50 [15%]). Combination PD-1/CTLA-4 deaths were frequently from colitis (32 [37%]) and myocarditis (22 [25%]). Fatal toxic effects typically occurred early after therapy initiation for combination therapy, anti-PD-1, and ipilimumab monotherapy (median 14.5, 40, and 40 days, respectively). Myocarditis had the highest fatality rate (52 [39.7%] of 131 reported cases), whereas endocrine events and colitis had only 2% to 5% reported fatalities; 10% to 17% of other organ-system toxic effects reported had fatal outcomes. Retrospective review of 3545 patients treated with ICIs from 7 academic centers revealed 0.6% fatality rates; cardiac and neurologic events were especially prominent (43%). Median time from symptom onset to death was 32 days. A meta-analysis of 112 trials involving 19 217 patients showed toxicity-related fatality rates of 0.36% (anti-PD-1), 0.38% (anti-PD-L1), 1.08% (anti-CTLA-4), and 1.23% (PD-1/PD-L1 plus CTLA-4). Conclusions and Relevance: In the largest evaluation of fatal ICI-associated toxic effects published to date to our knowledge, we observed early onset of death with varied causes and frequencies depending on therapeutic regimen. Clinicians across disciplines should be aware of these uncommon lethal complications.

Age Correlates with Response to Anti-PD1, Reflecting Age-Related Differences in Intratumoral Effector and Regulatory T-Cell Populations.

Purpose: We have shown that the aged microenvironment increases melanoma metastasis, and decreases response to targeted therapy, and here we queried response to anti-PD1.Experimental Design: We analyzed the relationship between age, response to anti-PD1, and prior therapy in 538 patients. We used mouse models of melanoma, to analyze the intratumoral immune microenvironment in young versus aged mice and confirmed our findings in human melanoma biopsies.Results: Patients over the age of 60 responded more efficiently to anti-PD-1, and likelihood of response to anti-PD-1 increased with age, even when we controlled for prior MAPKi therapy. Placing genetically identical tumors in aged mice (52 weeks) significantly increased their response to anti-PD1 as compared with the same tumors in young mice (8 weeks). These data suggest that this increased response in aged patients occurs even in the absence of a more complex mutational landscape. Next, we found that young mice had a significantly higher population of regulatory T cells (Tregs), skewing the CD8+:Treg ratio. FOXP3 staining of human melanoma biopsies revealed similar increases in Tregs in young patients. Depletion of Tregs using anti-CD25 increased the response to anti-PD1 in young mice.Conclusions: While there are obvious limitations to our study, including our inability to conduct a meta-analysis due to a lack of available data, and our inability to control for mutational burden, there is a remarkable consistency in these data from over 500 patients across 8 different institutes worldwide. These results stress the importance of considering age as a factor for immunotherapy response. Clin Cancer Res; 24(21); 5347-56. ©2018 AACR See related commentary by Pawelec, p. 5193.

Immune Checkpoint Inhibitor Therapy in Patients With Autoimmune Disease.

Immune checkpoint inhibitors have demonstrated efficacy across many cancer types in numerous clinical trials. However, because patients with preexisting autoimmune disease were excluded from these seminal trials, there are serious gaps in knowledge regarding the efficacy-and in particular the safety-of these transformative agents in patients with autoimmune disease. The safety of immune checkpoint inhibitors in this population has been an important concern, since these agents unleash immune activation, a potentially dangerous situation for patients with already heightened and aberrant immune function. Several retrospective studies have begun to address this question, finding that autoimmunity is often exacerbated by immune checkpoint inhibitor therapy, but is generally manageable with standard treatment algorithms and close multidisciplinary monitoring. Further, the activity of these agents appears to be comparable to that seen in unselected patients. Here we detail the experience with immune checkpoint inhibitors in patients with autoimmune disease.