Anti-PD-1 alone or in combination with anti-CTLA-4 for advanced melanoma patients with liver metastases

BACKGROUND

The combination of anti-PD-1 and anti-CTLA-4 has been associated with improvement in response and survival over anti-PD-1 monotherapy in unselected patients with advanced melanoma. Whether patients with liver metastases also benefit from the combination of anti-PD-1 and anti-CTLA-4 over anti-PD-1, is unclear. In this study, we sought to assess whether the combination of anti-PD-1 and anti-CTLA-4 leads to better response, progression-free survival and overall survival, compared with anti-PD-1 monotherapy for patients with liver metastases.

METHODS

We have conducted an international multicentre retrospective study. Patients with advanced melanoma with liver metastases treated with 1st line anti-PD1 monotherapy or with anti-CTLA-4 were included. The endpoints of this study were: objective response rate, progression-free survival and overall survival.

RESULTS

With a median follow-up from commencement of anti-PD-1 monotherapy or in combination with anti-CTLA-4 of 47 months (95% CI, 42-51), objective response rate was higher with combination therapy (47%) versus anti-PD-1 monotherapy (35%) (p = 0.0027), while progression-free survival and overall survival were not statistically different between both treatment groups. However, on multivariable analysis with multiple imputation for missing values and adjusting for predefined variables, combination of anti-PD1 and anti-CTLA-4 was associated with higher objective response (OR 2.21, 1.46 - 3.36; p < 0.001), progression-free survival (HR 0.73, 0.57 - 0.92; p = 0.009) and overall survival (HR 0.71, 0.54 - 0.94; p = 0.018) compared to anti-PD1 monotherapy.

CONCLUSIONS

Findings from this study will help guide treatment selection for patients who present with liver metastases, suggesting that combination therapy should be considered for this group of patients.

Completion of Pembrolizumab in Advanced Non-Small Cell Lung Cancer-Real World Outcomes After Two Years of Therapy (COPILOT)

BACKGROUND

Seminal trials with first-line pembrolizumab for metastatic non-small cell lung cancer (NSCLC) mandated a maximum two-years treatment. We describe real-world outcomes of a multi-site Australian cohort of patients who completed two-years of pembrolizumab.

METHODS

Retrospective data were collected from the national AUstralian Registry and biObank of thoRacic cAncers (AURORA). Primary endpoints were progression rate post pembrolizumab discontinuation; and progression free survival (PFS). Local treatment of oligoprogressive disease during pembrolizumab was allowed.

RESULTS

A total of 71 patients from six centers, median age 66.0 years, 49% male and 90% ECOG ≤ 1 were identified. Patients were Caucasian (82%) or Asian (16%); past (66%) or current (24%) smokers with mean 37 pack-years. Histology comprised 73% adenocarcinoma and 16% squamous. 18 patients (25%) had brain metastases at diagnosis. Median PD-L1 tumor proportion score (TPS) was 68%; 12 patients (17%) TPS < 1% and 43 (61%) TPS ≥ 50%. No patients had EGFR/ALK/ROS1 alterations; 29/49 tested (60%) had KRAS mutations. Median follow up was 38.7 months. Objective response rate 78.6%. Median PFS 46.1 months (95% CI 39.5-NR), not reached (46.1-NR) in PD-L1 TPS ≥ 1% versus 28.1 months (16.3-NR) in TPS < 1% (P = .013). 17 patients (24%) received additional local therapy for oligoprogression. Post pembrolizumab discontinuation, 20 patients (28%) had disease progression. Higher rates of progression occurred with TPS < 1% (OR 3.46, P = .06), without complete response (OR 5.06, P = .04), and with treated oligoprogression (OR 3.11, P = .05). 36-month landmark survival was 98.2%.

CONCLUSION

Patients completing two-years of pembrolizumab for NSCLC in an Australian cohort had high rates of KRAS mutation and PD-L1 expression; a proportion had brain metastases and treated oligoprogression. Progression post pembrolizumab was higher in PD-L1 TPS < 1% and in those without complete response.

Stroma-infiltrating T cell spatiotypes define immunotherapy outcomes in adolescent and young adult patients with melanoma

The biological underpinnings of therapeutic resistance to immune checkpoint inhibitors (ICI) in adolescent and young adult (AYA) melanoma patients are incompletely understood. Here, we characterize the immunogenomic profile and spatial architecture of the tumor microenvironment (TME) in AYA (aged ≤ 30 years) and older adult (aged 31-84 years) patients with melanoma, to determine the AYA-specific features associated with ICI treatment outcomes. We identify two ICI-resistant spatiotypes in AYA patients with melanoma showing stroma-infiltrating lymphocytes (SILs) that are distinct from the adult TME. The SILhigh subtype was enriched in regulatory T cells in the peritumoral space and showed upregulated expression of immune checkpoint molecules, while the SILlow subtype showed a lack of immune activation. We establish a young immunosuppressive melanoma score that can predict ICI responsiveness in AYA patients and propose personalized therapeutic strategies for the ICI-resistant subgroups. These findings highlight the distinct immunogenomic profile of AYA patients, and individualized TME features in ICI-resistant AYA melanoma that require patient-specific treatment strategies.

Combined immunotherapy in melanoma patients with brain metastases: A multicenter international study

BACKGROUND

Ipilimumab plus nivolumab (COMBO) is the standard treatment in asymptomatic patients with melanoma brain metastases (MBM). We report a retrospective study aiming to assess the outcome of patients with MBM treated with COMBO outside clinical trials.

METHODS

Consecutive patients treated with COMBO have been included. Demographics, steroid treatment, Central Nervous System (CNS)-related symptoms, BRAF status, radiotherapy or surgery, response rate (RR), progression-free (PFS) and overall survival (OS) have been analyzed.

RESULTS

376 patients were included: 262 received COMBO as first-line and 114 as a subsequent line of therapy, respectively. In multivariate analysis, Eastern Cooperative Oncology Group (ECOG) (≥1 vs 0) [HR 1.97 (1.46-2.66)], extracerebral metastases [HR 1.92 (1.09-3.40)], steroid use at the start of COMBO [HR 1.59 (1.08-2.38)], CNS-related symptoms [HR 1.59 (1.08-2.34)], SRS (Stereotactic radiosurgery) [HR 0.63 (0.45-0.88)] and surgery [HR 0.63 (0.43-0.91)] were associated with OS. At a median follow-up of 30 months, the median OS (mOS) in the overall population was 21.3 months (18.1-24.5), whilst OS was not yet reached in treatment-naive patients, steroid-free at baseline. In patients receiving COMBO after BRAF/MEK inhibitors(i) PFS at 1-year was 15.7%. The dose of steroids (dexamethasone < vs ≥ 4 mg/day) was not prognostic. SRS alongside COMBO vs COMBO alone in asymptomatic patients prolonged survival. (p = 0.013). Toxicities were consistent with previous studies. An independent validation cohort (n = 51) confirmed the findings.

CONCLUSIONS

Our results demonstrate remarkable long-term survival in treatment-naïve, asymptomatic, steroid-free patients, as well as in those receiving SRS plus COMBO. PFS and OS were poor in patients receiving COMBO after progressing to BRAF/MEKi.

First-line chemoimmunotherapy and immunotherapy in patients with non-small cell lung cancer and brain metastases: a registry study

Introduction

Brain metastases commonly occur in patients with non-small cell lung cancer (NSCLC). Standard first-line treatment for NSCLC, without an EGFR, ALK or ROS1 mutation, is either chemoimmunotherapy or anti-PD-1 monotherapy. Traditionally, patients with symptomatic or untreated brain metastases were excluded from the pivotal clinical trials that established first-line treatment recommendations. The intracranial effectiveness of these treatment protocols has only recently been elucidated in small-scale prospective trials.

Methods

Patients with NSCLC and brain metastases, treated with first-line chemoimmunotherapy or anti-PD-1 monotherapy were selected from the Australian Registry and biObank of thoracic cancers (AURORA) clinical database covering seven institutions. The primary outcome was a composite time-to-event (TTE) outcome, including extracranial and intracranial progression, death, or need for local intracranial therapy, which served as a surrogate for disease progression. The secondary outcome included overall survival (OS), intracranial objective response rate (iORR) and objective response rate (ORR).

Results

116 patients were included. 63% received combination chemoimmunotherapy and 37% received anti-PD-1 monotherapy. 69% of patients received upfront local therapy either with surgery, radiotherapy or both. The median TTE was 7.1 months (95% CI 5 - 9) with extracranial progression being the most common progression event. Neither type of systemic therapy or upfront local therapy were predictive of TTE in a multivariate analysis. The median OS was 17 months (95% CI 13-27). Treatment with chemoimmunotherapy was predictive of longer OS in multivariate analysis (HR 0.35; 95% CI 0.14 - 0.86; p=0.01). The iORR was 46.6%. The iORR was higher in patients treated with chemoimmunotherapy compared to immunotherapy (58% versus 31%, p=0.01). The use of chemoimmunotherapy being predictive of iORR in a multivariate analysis (OR 2.88; 95% CI 1.68 - 9.98; p=0.04).

Conclusion

The results of this study of real-world data demonstrate the promising intracranial efficacy of chemoimmunotherapy in the first-line setting, potentially surpassing that of immunotherapy alone. No demonstrable difference in survival or TTE was seen between receipt of upfront local therapy. Prospective studies are required to assist clinical decision making regarding optimal sequencing of local and systemic therapies.

Seasonal patterns of toxicity in melanoma patients treated with combination anti-PD-1 and anti-CTLA-4 immunotherapy

BACKGROUND

Immune checkpoint inhibitors are frequently associated with the development of immunotherapy-related adverse events (irAEs). The exact etiology, including the role of environmental factors, remains incompletely understood.

METHODS

We analyzed the records of 394 melanoma patients from three centers (northern and southern hemisphere). Patients had received at least one cycle of anti-PD-1/anti-CTLA-4 with a minimum follow-up of 3 months. We study the distribution and time to irAEs onset throughout the calendar year.

RESULTS

764 irAEs were recorded; the most frequent were skin rash (35%), hepatitis (32%) and colitis (30%). The irAEs incidence was the highest in autumn and winter, and the ratio for the 'number of irAEs' per 'therapies commenced' was the highest in winter and lowest in summer (2.4 and 1.7, respectively). Season-specific patterns in the time of irAEs onset were observed for pneumonitis (shorter time to onset in autumn, p = 0.025), hepatitis (shorter time to onset in spring, p = 0.016) and sarcoid-like immune reaction (shorter time to onset in autumn, p = 0.041). Season-specific patterns for early-onset irAEs were observed for hepatitis (spring, p = 0.023) and nephritis (summer, p = 0.017). Early-onset pneumonitis was more frequent in autumn-winter (p = 0.008) and early-onset nephritis in spring-summer (p = 0.004).

CONCLUSIONS

Environmental factors that are associated with particular seasons may contribute to the development of certain irAEs and suggest the potential effect of environmental triggers. The identification of these factors may enhance preventive and therapeutic strategies to reduce the morbidity of irAEs.

VEGF Inhibitors Improve Survival Outcomes in Patients with Liver Metastases across Cancer Types-A Meta-Analysis

BACKGROUND

Liver metastases are associated with poor prognosis across cancers. Novel treatment strategies to treat patients with liver metastases are needed. This meta-analysis aimed to assess the efficacy of vascular endothelial growth factor inhibitors in patients with liver metastases across cancers.

METHODS

A systematic search of PubMed, Cochrane CENTRAL, and Embase was performed between January 2000 and April 2023. Randomized controlled trials of patients with liver metastases comparing standard of care (systemic therapy or best supportive care) with or without vascular endothelial growth factor inhibitors were included in the study. Outcomes reported included progression-free survival and overall survival.

RESULTS

A total of 4445 patients with liver metastases from 25 randomized controlled trials were included in this analysis. The addition of vascular endothelial growth factor inhibitors to standard systemic therapy or best supportive care was associated with superior progression-free survival (HR = 0.49; 95% CI, 0.40-0.61) and overall survival (HR = 0.83; 95% CI, 0.74-0.93) in patients with liver metastases. In a subgroup analysis of patients with versus patients without liver metastases, the benefit with vascular endothelial growth factor inhibitors was more pronounced in the group with liver metastases (HR = 0.44) versus without (HR = 0.57) for progression-free survival, but not for overall survival.

CONCLUSION

The addition of vascular endothelial growth factor inhibitors to standard management improved survival outcomes in patients with liver metastasis across cancers.

Lag-3 expression and clinical outcomes in metastatic melanoma patients treated with combination anti-lag-3 + anti-PD-1-based immunotherapies

Lymphocyte-activation gene-3 (LAG-3), an immune checkpoint receptor, negatively regulates T-cell function and facilitates immune escape of tumors. Dual inhibition of LAG-3 and programmed cell death receptor-1 (PD-1) significantly improved progression-free survival (PFS) in metastatic melanoma patients compared to anti-PD-1 therapy alone. Investigating the utility of LAG-3 expression as a biomarker of response to anti-LAG-3 + anti-PD-1 immunotherapy is of great clinical relevance. This study sought to evaluate the association between baseline LAG-3 expression and clinical outcomes following anti-LAG-3 and anti-PD-1-based immunotherapy in metastatic melanoma. LAG-3 immunohistochemistry (clone D2G4O) was performed on pre-treatment formalin-fixed, paraffin-embedded metastatic melanoma specimens from 53 patients treated with combination anti-LAG-3 + anti-PD-1-based therapies. Eleven patients had received prior anti-PD-1-based treatment. Patients were categorized as responders (complete/partial response; n = 36) or non-responders (stable/progressive disease; n = 17) based on the Response Evaluation Criteria in Solid Tumours (RECIST). Tumor-infiltrating lymphocytes (TILs) were scored on hematoxylin and eosin-stained sections. LAG-3 expression was observed in 81% of patients, with staining in TILs and dendritic cells. Responders displayed significantly higher proportions of LAG-3+ cells compared to non-responders (P = .0210). LAG-3 expression positively correlated with TIL score (P < .01). There were no significant differences in LAG-3 expression between different sites of metastases (P > .05). Patients with ≥ 1% LAG-3+ cells in their tumors had significantly longer PFS compared to patients with < 1% LAG-3 expression (P = .0037). No significant difference was observed in overall survival between the two groups (P = .1417). Therefore, the assessment of LAG-3 expression via IHC warrants further evaluation to determine its role as a predictive marker of response and survival in metastatic melanoma.

Definitive treatment with PD-1 blockade and radiation therapy of unresected primary desmoplastic melanoma of the nose

Two patients with primary desmoplastic melanoma of the nose were treated with definitive anti-PD-1 checkpoint inhibitor (anti-PD1) and radiation therapy. Both patients were technically resectable with partial rhinectomy but both declined for cosmetic reasons. The melanoma multidisciplinary team recommended that the patients receive PD1 blockade. The initial response to PD-1 blockade was temporary in the first case and partial in the second one. With the addition of high-dose radiotherapy, complete responses were obtained in both patients, with recurrence-free and good functional and cosmetic outcomes at a six-year and 22-month follow-up. Despite surgery being the gold standard, both cases illustrated that PD-1 blockade and radiation therapy can be a safe alternative option for desmoplastic melanoma where surgery is morbidly disfiguring.

Classification of the tumor immune microenvironment and associations with outcomes in patients with metastatic melanoma treated with immunotherapies

BACKGROUND

Tumor microenvironment (TME) characteristics are potential biomarkers of response to immune checkpoint inhibitors in metastatic melanoma. This study developed a method to perform unsupervised classification of TME of metastatic melanoma.

METHODS

We used multiplex immunohistochemical and quantitative pathology-derived assessment of immune cell compositions of intratumoral and peritumoral regions of metastatic melanoma baseline biopsies to classify TME in relation to response to anti-programmed cell death protein 1 (PD-1) monotherapy or in combination with anti-cytotoxic T-cell lymphocyte-4 (ipilimumab (IPI)+PD-1).

RESULTS

Spatial profiling of CD8+T cells, macrophages, and melanoma cells, as well as phenotypic PD-1 receptor ligand (PD-L1) and CD16 proportions, were used to identify and classify patients into one of three mutually exclusive TME classes: immune-scarce, immune-intermediate, and immune-rich tumors. Patients with immune-rich tumors were characterized by a lower proportion of melanoma cells and higher proportions of immune cells, including higher PD-L1 expression. These patients had higher response rates and longer progression-free survival (PFS) than those with immune-intermediate and immune-scarce tumors. At a median follow-up of 18 months (95% CI: 6.7 to 49 months), the 1-year PFS was 76% (95% CI: 64% to 90%) for patients with an immune-rich tumor, 56% (95% CI: 44% to 72%) for those with an immune-intermediate tumor, and 33% (95% CI: 23% to 47%) for patients with an immune-scarce tumor. A higher response rate was observed in patients with an immune-scarce or immune-intermediate tumor when treated with IPI+PD-1 compared with those treated with PD-1 alone.

CONCLUSIONS

Our study provides an automatic TME classification method that may predict the clinical efficacy of immunotherapy for patients with metastatic melanoma.

Small-Cell Lung Cancer-An Update on Targeted and Immunotherapies

Small-cell lung cancer (SCLC) is an aggressive disease with distinct biological and clinical features. The clinical course of SCLC is generally characterised by initial sensitivity to DNA-damaging therapies, followed by early relapse and broad cross resistance to second line agents. Whilst there has been an enormous expansion of effective targeted and immune-based therapeutic options for non-small cell lung cancer (NSCLC) in the last decade, little improvement has been achieved in SCLC treatment and survival due, at least in part, to underappreciated inter- and intra-tumoral heterogeneity. Here we review the current treatment paradigm of SCLC including recent advances made in utilizing immunotherapy and the challenges of identifying a predictive biomarker for immunotherapy response. We examine emerging new targeted therapies, combination immunotherapy and future directions of SCLC treatment research.

Abstract 6747: Sites of metastases prior to systemic treatment influence progression patterns and survival in stage IV melanoma patients

Background: Different metastatic sites have distinct response rates to immune checkpoint inhibitors (ICI), suggesting that anatomical locations play a role in treatment response and survival. This project investigated the impact that sites of metastases present at baseline - ie. before starting treatment - have on the anatomical patterns of progression and their association with survival in patients (pts) exposed to ICI and BRAF/MEK inhibitors (BRAF/MEKi) as first line treatment.

Methods: We curated the progression history of distant metastases of 568 stage IV pts; 352 pts had first line treatment with antiPD1 +/- antiCTLA4, and 216 pts had first line BRAF/MEKi. We sought to investigate the association between sites of metastases at baseline and (a) sites of progression in pts who failed first line anti-PD1 vs first line BRAF/MEKi, (b) sites of progression in pts who failed first line anti-PD1 with innate vs acquired resistance, and (c) survival of all pts, from time of first line treatment to last follow-up.

Results: Using a sophisticated mathematical graph representation of anatomical disease progression, we unveiled sites of metastases at baseline that impacted where new sites of metastases developed on treatment failure. In pts with brain metastasis at baseline, pts who failed anti-PD1 had higher progression in the brain compared to BRAF/MEKi progressors (68.1% in anti-PD1 progressors vs 62.5% in BRAF/MEKi progressors). In contrast, the opposite trend was observed in the progression to the brain in pts with no brain metastasis at baseline, which was lower in anti-PD1 progressors compared to BRAF/MEKi progressors (20.6% in anti-PD1 progressors vs 32.6% in BRAF/MEKi progressors).Within pts who failed anti-PD1, pts with innate resistance (n=95) had a higher rate of progression in the brain (42.1%) compared to pts with acquired (n=36) resistance (25%). Among pts with innate resistance who had brain metastasis at baseline (n=36), 80.6% progressed in the brain. In contrast, among pts with innate resistance without brain metastasis at baseline (n=59), only 18.6% progressed to the brain.Sites of metastases at baseline also had an impact on the survival of pts. In BRAF/MEKi pts, brain metastasis at baseline was not associated with survival (log-rank p-value=0.6). In contrast, anti-PD1 pts with brain metastasis at baseline had worst survival (2-yr survival 56%) compared to pts without brain metastasis at baseline (2-yr survival 73%, log-rank p-value=0.005).

Utilisation of this graph representation for the development of a time-dependent predictor of brain metastases will be presented.

Further associations of metastatic sites of disease at baseline with progression and survival will be discussed.

Conclusions: Different sites of metastases at baseline have a distinct effect on the progression patterns and survival of pts who received BRAF/MEKi or anti-PD1 as first line treatment.

Citation Format: Ismael A. Vergara, Serigne N. Lo, Isabel Li, Alexander M. Menzies, Matteo S. Carlino, Richard A. Scolyer, Georgina V. Long, Ines Pires da Silva. Sites of metastases prior to systemic treatment influence progression patterns and survival in stage IV melanoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6747.

Durability of response to immune checkpoint inhibitors in metastatic Merkel cell carcinoma after treatment cessation

BACKGROUND

Metastatic Merkel cell carcinoma (mMCC) is highly responsive to immune checkpoint inhibitors (ICIs); however, durability of response after treatment cessation and response to retreatment in the setting of progression is unknown.

METHODS

Patients (pts) having mMCC from 10 centres who discontinued ICI treatment for a reason other than progression were studied.

RESULTS

Forty patients were included. Median time on treatment was 13.5 months (range 1-35). Thirty-one patients (77.5%) stopped treatment electively while 9 patients (22.5%) stopped due to treatment-related toxicity. After median of 12.3 months from discontinuation, 14 pts (35%) have progressed (PD). Disease progression rate following ICI discontinuation was 26% (8 of 31) in patients who discontinued in complete response (CR), 57% (4 of 7) in patients in partial response and 100% (2 of 2) in those with stable disease. Median progression-free survival (PFS) after treatment cessation was 21 months (95% confidence interval [CI], 18- not reached [NR]), with a third of patients progressing during their first year off treatment. PFS was longer for patients who discontinued ICI electively (median PFS 29 months; 95% CI, 21-NR) compared to those who stopped due to toxicity (median PFS 11 months; 95% CI, 10-NR). ICI was restarted in 8 of 14 pts (57%) with PD, with response rate of 75% (4 CR, 2 partial response, 1 stable disease, 1 PD).

CONCLUSION

ICI responses in mMCC do not appear durable off treatment, including in patients who achieve a CR, though response to retreatment is promising. Extended duration of treatment needs to be investigated to optimise long-term outcomes.

Five‐year survival and clinical correlates among patients with advanced non‐small cell lung cancer, melanoma and renal cell carcinoma treated with immune check‐point inhibitors in Australian tertiary oncology centres

AIMS

There is robust trial evidence for improved overall survival (OS) with immunotherapy in advanced solid organ malignancies. The real-world long-term survival data and the predictive variables are not yet known. Our aim was to evaluate factors associated with 3-year and 5-year OS for patients treated with immune checkpoint inhibitors (ICIs).

METHODS

We performed a retrospective study of patients who received ICIs as management of advanced solid organ malignancies in two tertiary Australian oncology centres from 2012-2017. Data pertaining to clinical characteristics, metastatic disease burden, immune-related adverse events (IRAEs) and tumour responses were collected and their relationship to survival examined.

RESULTS

In this analysis of 264 patients, 202 (76.5%) had melanoma, 46 (17.4%) had non-small cell lung cancer (NSCLC), 12 (4.5%) had renal cell carcinoma (RCC) and 4 (1.5%) had mesothelioma. The 5-year OS rates were 42.1% in patients with melanoma, 19.6% with NSCLC, 75% with RCC, and none of the mesothelioma patients were alive at 5 years. In multivariate analysis, an ECOG score of 0 (Hazard ratio [HR] 0.39; 95% confidence interval [CI] 0.23-0.66; p < 0.001) and the occurrence of IRAE's of any grade (HR 0.61; 95% CI 0.37-0.95; p = 0.05) were associated with better 5-year survival. The presence of bone metastases (HR 1.62; 95% CI 1.03-2.82; p = 0.05) and liver metastases (HR 1.76; 95% CI 1.07-2.89; p = 0.03) were associated with worse 5-year survival.

CONCLUSIONS

These results support the long-term benefits of immunotherapy that in some patients, extend to at least 5 years. ECOG performance status of 0 and the occurrence of irAEs are associated with better long-term survival. Survival is significantly influenced by metastatic site and cancer type. These predictive clinical correlates aid discussions and planning in the delivery of ICIs to patients.

Distinct pretreatment innate immune landscape and posttreatment T cell responses underlie immunotherapy-induced colitis

Immune-related adverse events represent a major hurdle to the success of immunotherapy. The immunological mechanisms underlying their development and relation to antitumor responses are poorly understood. By examining both systemic and tissue-specific immune changes induced by combination anti-CTLA-4 and anti-PD-1 immunotherapy, we found distinct repertoire changes in patients who developed moderate-severe colitis, irrespective of their antitumor response to therapy. The proportion of circulating monocytes were significantly increased at baseline in patients who subsequently developed colitis compared with patients who did not develop colitis, and biopsies from patients with colitis showed monocytic infiltration of both endoscopically and histopathologically normal and inflamed regions of colon. The magnitude of systemic expansion of T cells following commencement of immunotherapy was also greater in patients who developed colitis. Importantly, we show expansion of specific T cell subsets within inflamed regions of the colon, including tissue-resident memory CD8+ T cells and Th1 CD4+ T cells in patients who developed colitis. Our data also suggest that CD8+ T cell expansion was locally induced, while Th1 cell expansion was systemic. Together, our data show that exaggerated innate and T cell responses to combination immunotherapy synergize to propel colitis in susceptible patients.

Causes, consequences and clinical significance of aneuploidy across melanoma subtypes

Aneuploidy, the state of the cell in which the number of whole chromosomes or chromosome arms becomes imbalanced, has been recognized as playing a pivotal role in tumor evolution for over 100 years. In melanoma, the extent of aneuploidy, as well as the chromosomal regions that are affected differ across subtypes, indicative of distinct drivers of disease. Multiple studies have suggested a role for aneuploidy in diagnosis and prognosis of melanomas, as well as in the context of immunotherapy response. A number of key constituents of the cell cycle have been implicated in aneuploidy acquisition in melanoma, including several driver mutations. Here, we review the state of the art on aneuploidy in different melanoma subtypes, discuss the potential drivers, mechanisms underlying aneuploidy acquisition as well as its value in patient diagnosis, prognosis and response to immunotherapy treatment.

Unveiling the tumor immune microenvironment of organ-specific melanoma metastatic sites

Background

The liver is a known site of resistance to immunotherapy and the presence of liver metastases is associated with shorter progression-free and overall survival (OS) in melanoma, while lung metastases have been associated with a more favorable outcome. There are limited data available regarding the immune microenvironment at different anatomical sites of melanoma metastases. This study sought to characterize and compare the tumor immune microenvironment of liver, brain, lung, subcutaneous (subcut) as well as lymph node (LN) melanoma metastases.

Methods

We analyzed OS in 1924 systemic treatment-naïve patients with AJCC (American Joint Committee on Cancer) stage IV melanoma with a solitary site of organ metastasis. In an independent cohort we analyzed and compared immune cell densities, subpopulations and spatial distribution in tissue from liver, lung, brain, LN or subcut sites from 130 patients with stage IV melanoma.

Results

Patients with only liver, brain or bone metastases had shorter OS compared to those with lung, LN or subcutaneous and soft tissue metastases. Liver and brain metastases had significantly lower T-cell infiltration than lung (p=0.0116 and p=0.0252, respectively) and LN metastases (p=0.0116 and p=0.0252, respectively). T cells were further away from melanoma cells in liver than lung metastases (p=0.0335). Liver metastases displayed unique T-cell profiles, with a significantly lower proportion of programmed cell death protein-1+ T cells compared to all other anatomical sites (p<0.05), and a higher proportion of TIM-3+ T cells compared to LN (p=0.0004), subcut (p=0.0082) and brain (p=0.0128) metastases. Brain metastases had a lower macrophage density than subcut (p=0.0105), liver (p=0.0095) and lung (p<0.0001) metastases. Lung metastases had the highest proportion of programmed death ligand-1+ macrophages of the total macrophage population, significantly higher than brain (p<0.0001) and liver metastases (p=0.0392).

Conclusions

Liver and brain melanoma metastases have a significantly reduced immune infiltrate than lung, subcut and LN metastases, which may account for poorer prognosis and reduced immunotherapy response rates in patients with liver or brain metastases. Increased TIM-3 expression in liver metastases suggests TIM-3 inhibitor therapy as a potential therapeutic opportunity to improve patient outcomes.

Detailed spatial immunophenotyping of primary melanomas reveals immune cell subpopulations associated with patient outcome

While the tumor immune microenvironment (TIME) of metastatic melanoma has been well characterized, the primary melanoma TIME is comparatively poorly understood. Additionally, although the association of tumor-infiltrating lymphocytes with primary melanoma patient outcome has been known for decades, it is not considered in the current AJCC melanoma staging system. Detailed immune phenotyping of advanced melanoma has revealed multiple immune biomarkers, including the presence of CD8+ T-cells, for predicting response to immunotherapies. However, in primary melanomas, immune biomarkers are lacking and CD8+ T-cells have yet to be extensively characterized. As recent studies combining immune features and clinicopathologic characteristics have created more accurate predictive models, this study sought to characterize the TIME of primary melanomas and identify predictors of patient outcome. We first phenotyped CD8+ T cells in fresh stage II primary melanomas using flow cytometry (n = 6), identifying a CD39+ tumor-resident CD8+ T-cell subset enriched for PD-1 expression. We then performed Opal multiplex immunohistochemistry and quantitative pathology-based immune profiling of CD8+ T-cell subsets, along with B cells, NK cells, Langerhans cells and Class I MHC expression in stage II primary melanoma specimens from patients with long-term follow-up (n = 66), comparing patients based on their recurrence status at 5 years after primary diagnosis. A CD39+CD103+PD-1- CD8+ T-cell population (P2) comprised a significantly higher proportion of intratumoral and stromal CD8+ T-cells in patients with recurrence-free survival (RFS) ≥5 years vs those with RFS <5 years (p = 0.013). Similarly, intratumoral B cells (p = 0.044) and a significantly higher B cell density at the tumor/stromal interface were associated with RFS. Both P2 and B cells localized in significantly closer proximity to melanoma cells in patients who remained recurrence-free (P2 p = 0.0139, B cell p = 0.0049). Our results highlight how characterizing the TIME in primary melanomas may provide new insights into how the complex interplay of the immune system and tumor can modify the disease outcomes. Furthermore, in the context of current clinical trials of adjuvant anti-PD-1 therapies in high-risk stage II primary melanoma, assessment of B cells and P2 could identify patients at risk of recurrence and aid in long-term treatment decisions at the point of primary melanoma diagnosis.

Lack of association between anatomical sites of scalp melanomas and brain metastases does not support direct vascular spread

Primary scalp melanomas are associated with a higher rate of brain metastasis than primary cutaneous melanomas occurring at other head and neck and body sites, but the reason is unclear. Spread to brain parenchyma via emissary veins draining from the scalp to dural sinuses has been suggested. We sought to examine the locations of metastases from primary scalp and nonscalp head and neck melanomas to determine whether there was anatomical evidence supporting direct venous spread to the brain. Data from patients who developed distant metastases from cutaneous head and neck melanomas (CHNMs) between 2000 and 2018 were analyzed. Anatomical sites of primary scalp melanomas and their respective intracranial metastases were compared. Times to first brain and nonbrain metastases were investigated for scalp and nonscalp primary CHNMs. Of 693 patients with CHNMs, 244 developed brain metastases: 109 (44.7%) had scalp primaries and 135 (55.3%) had nonscalp primaries. There was no significant association between anatomical sites of scalp primary melanomas and brain metastases (Cramer's V = 0.21; Chi-square P = 0.63). Compared with nonscalp CHNMs, scalp melanomas had no greater propensity for the brain as the first distant metastatic site ( P = 0.52) but had a shorter time to both brain metastasis (76.3 vs. 168.5 months; P < 0.001) and nonbrain metastasis (22.6 vs. 35.8 months; P < 0.001). No evidence was found to support a direct vascular pathway for metastatic spread of scalp melanomas to the brain. The increased incidence of brain metastases from scalp melanomas is probably driven by aggressive biological mechanisms.

Efficacy and safety of anti-PD1 monotherapy or in combination with ipilimumab after BRAF/MEK inhibitors in patients with BRAF mutant metastatic melanoma

BACKGROUND

Patients with V600BRAF mutant metastatic melanoma have higher rates of progression-free survival (PFS) and overall survival (OS) with first-line anti-PD1 (PD1]+anti-CTLA-4 (IPI) versus PD1. Whether this is also true after BRAF/MEKi therapy is unknown. We aimed to determine the efficacy and safety of PD1 versus IPI +PD1 after BRAF/MEK inhibitors (BRAF/MEKi).

METHODS

Patients with V600BRAF mutant metastatic melanoma treated with BRAF/MEKi who had subsequent PD1 versus IPI+PD1 at eight centers were included. The endpoints were objective response rate (ORR), PFS, OS and safety in each group.

RESULTS

Of 200 patients with V600E (75%) or non-V600E (25%) mutant metastatic melanoma treated with BRAF/MEKi (median time of treatment 7.6 months; treatment cessation due to progressive disease in 77%), 115 (57.5%) had subsequent PD1 and 85 (42.5%) had IPI+PD1. Differences in patient characteristics between PD1 and IPI+PD1 groups included, age (med. 63 vs 54 years), time between BRAF/MEKi and PD1±IPI (16 vs 4 days), Eastern Cooperative Oncology Group Performance Status (ECOG PS) of ≥1 (62% vs 44%), AJCC M1C/M1D stage (72% vs 94%) and progressing brain metastases at the start of PD1±IPI (34% vs 57%). Median follow-up from PD1±IPI start was 37.8 months (95% CI, 33.9 to 52.9). ORR was 36%; 34% with PD1 vs 39% with IPI+PD1 (p=0.5713). Median PFS was 3.4 months; 3.4 with PD1 vs 3.6 months with IPI+PD1 (p=0.6951). Median OS was 15.4 months; 14.4 for PD1 vs 20.5 months with IPI+PD1 (p=0.2603). The rate of grade 3 or 4 toxicities was higher with IPI+PD1 (31%) vs PD1 (7%). ORR, PFS and OS were numerically higher with IPI+PD1 vs PD1 across most subgroups except for females, those with <10 days between BRAF/MEKi and PD1±IPI, and those with stage III/M1A/M1B melanoma. The combination of ECOG PS=0 and absence of liver metastases identified patients with >3 years OS (area under the curve, AUC=0.74), while ECOG PS ≥1, progressing brain metastases and presence of bone metastases predicted primary progression (AUC=0.67).

CONCLUSIONS

IPI+PD1 and PD1 after BRAF/MEKi have similar outcomes despite worse baseline prognostic features in the IPI+PD1 group, however, IPI+PD1 is more toxic. A combination of clinical factors can identify long-term survivors, but less accurately those with primary resistance to immunotherapy after targeted therapy.

Higher proportions of CD39+ tumor-resident cytotoxic T cells predict recurrence-free survival in patients with stage III melanoma treated with adjuvant immunotherapy

BACKGROUND

Adjuvant immune checkpoint inhibitor (ICI) immunotherapies have significantly reduced the recurrence rate in high-risk patients with stage III melanoma compared with surgery alone. However, 48% of anti-PD-1-treated patients will develop recurrent disease within 4 years. There is a need to identify biomarkers of recurrence after adjuvant ICI to enable identification of patients in need of alternative treatment strategies. As cytotoxic T cells are critical for the antitumor response to anti-PD-1, we sought to determine whether specific subsets were predictive of recurrence in anti-PD-1-treated high-risk patients with stage III melanoma.

METHODS

Associations with recurrence in patients with stage III melanoma were sought by analyzing resection specimens (n=103) taken prior to adjuvant nivolumab/pembrolizumab±low-dose/low-interval ipilimumab. Multiplex immunohistochemistry was used to quantify intratumoral CD8+ T-cell populations using phenotypical markers CD39, CD103, and PD-1.

RESULTS

With a median follow-up of 19.3 months, 37/103 (36%) of patients had a recurrence. Two CD8+ T-cell subpopulations were significantly associated with recurrence. First, CD39+ tumor-resident memory cells (CD39+CD103+PD-1+CD8+ (CD39+ Trm)) comprised a significantly higher proportion of CD8+ T cells in recurrence-free patients (p=0.0004). Conversely, bystander T cells (CD39-CD103-PD-1-CD8+) comprised a significantly greater proportion of T cells in patients who developed recurrence (p=0.0002). Spatial analysis identified that CD39+ Trms localized significantly closer to melanoma cells than bystander T cells. Multivariable analysis confirmed significantly improved recurrence-free survival (RFS) in patients with a high proportion of intratumoral CD39+ Trms (1-year RFS high 78.1% vs low 49.9%, HR 0.32, 95% CI 0.15 to 0.69), no complete lymph node dissection performed, and less advanced disease stage (HR 2.85, 95% CI 1.13 to 7.19, and HR 1.29, 95% CI 0.59 to 2.82). The final Cox regression model identified patients who developed recurrence with an area under the curve of 75.9% in the discovery cohort and 69.5% in a separate validation cohort (n=33) to predict recurrence status at 1 year.

CONCLUSIONS

Adjuvant immunotherapy-treated patients with a high proportion of CD39+ Trms in their baseline melanoma resection have a significantly reduced risk of melanoma recurrence. This population of T cells may not only represent a biomarker of RFS following anti-PD-1 therapy, but may also be an avenue for therapeutic manipulation and enhancing outcomes for immunotherapy-treated patients with cancer.

Multiomic profiling of checkpoint inhibitor-treated melanoma: Identifying predictors of response and resistance, and markers of biological discordance

We concurrently examine the whole genome, transcriptome, methylome, and immune cell infiltrates in baseline tumors from 77 patients with advanced cutaneous melanoma treated with anti-PD-1 with or without anti-CTLA-4. We show that high tumor mutation burden (TMB), neoantigen load, expression of IFNγ-related genes, programmed death ligand expression, low PSMB8 methylation (therefore high expression), and T cells in the tumor microenvironment are associated with response to immunotherapy. No specific mutation correlates with therapy response. A multivariable model combining the TMB and IFNγ-related gene expression robustly predicts response (89% sensitivity, 53% specificity, area under the curve [AUC], 0.84); tumors with high TMB and a high IFNγ signature show the best response to immunotherapy. This model validates in an independent cohort (80% sensitivity, 59% specificity, AUC, 0.79). Except for a JAK3 loss-of-function mutation, for patients who did not respond as predicted there is no obvious biological mechanism that clearly explained their outlier status, consistent with intratumor and intertumor heterogeneity in response to immunotherapy.

Acquired resistance to anti-MAPK targeted therapy confers an immune-evasive tumor microenvironment and cross-resistance to immunotherapy in melanoma

How targeted therapies and immunotherapies shape tumors, and thereby influence subsequent therapeutic responses, is poorly understood. In the present study, we show, in melanoma patients and mouse models, that when tumors relapse after targeted therapy with MAPK pathway inhibitors, they are cross-resistant to immunotherapies, despite the different modes of action of these therapies. We find that cross-resistance is mediated by a cancer cell-instructed, immunosuppressive tumor microenvironment that lacks functional CD103+ dendritic cells, precluding an effective T cell response. Restoring the numbers and functionality of CD103+ dendritic cells can re-sensitize cross-resistant tumors to immunotherapy. Cross-resistance does not arise from selective pressure of an immune response during evolution of resistance, but from the MAPK pathway, which not only is reactivated, but also exhibits an increased transcriptional output that drives immune evasion. Our work provides mechanistic evidence for cross-resistance between two unrelated therapies, and a scientific rationale for treating patients with immunotherapy before they acquire resistance to targeted therapy.

Re-induction ipilimumab following acquired resistance to combination ipilimumab and anti-PD-1 therapy

PURPOSE

Combination immunotherapy with nivolumab and ipilimumab has a high initial response rate in advanced melanoma; however, up to 55% of patients later progress. The efficacy and safety of ipilimumab re-induction in the setting of acquired resistance (AR) to combination immunotherapy is unknown.

METHODS

Patients with advanced melanoma who initially achieved a complete response, partial response or sustained stable disease to induction combination immunotherapy then progressed and were reinduced with ipilimumab (alone or in combination with anti-PD-1) and were analysed retrospectively. Demographics, disease characteristics, efficacy and toxicity were examined.

RESULTS

Forty-seven patients were identified from 12 centres. The response rate to reinduction therapy was 12/47 (26%), and disease control rate was 21/47 (45%). Responses appeared more frequent in patients who developed AR after ceasing induction immunotherapy (30% vs. 18%, P = 0.655). Time to AR was 11 months (95% confidence interval [CI], 8-15 months). After a median follow-up of 16 months (95% CI, 10-25 months), responders to reinduction had a median progression-free survival of 14 months (95% CI, 13, NR months), and in the whole cohort, the median overall survival from reinduction was 17 months (95% CI, 12-NR months). Twenty-seven (58%) immune-related adverse events (irAEs) were reported; 18 (38%) were grade 3/4, and in 11 of 27 (40%), the same irAE observed during induction therapy recurred.

CONCLUSIONS

Reinduction with ipilimumab ± anti-PD-1 has modest clinical activity. Clinicians should be attentive to the risk of irAEs, including recurrence of irAEs that occurred during induction therapy. Future studies are necessary to determine best management after resistance to combination immunotherapy.

Re-defining the role of surgery in the management of patients with oligometastatic stage IV melanoma in the era of effective systemic therapies

Although previously the mainstay of treatment, the role of surgery in the management of patients with oligometastatic stage IV melanoma has changed with the advent of effective systemic therapies (most notably immunotherapy). Contemporary treatment options for patients with asymptomatic solitary or oligo-metastases include upfront surgery followed by adjuvant immunotherapy or upfront immunotherapy with salvage surgery as required. For suspected solitary or oligo-metastases, surgery serves both diagnostic and therapeutic purposes. Advances in radiological technology allow metastases to be detected earlier and surgery to be less morbid. Surgical morbidities are generally more tolerable than serious immune-related adverse effects, but surgery may be less effective. Upfront immunotherapy ensures that futile surgery is not offered for rapidly progressive disease. It also provides an opportunity to assess response to treatment, which predicts outcome, and may obviate the need for surgery. However, it is important not to miss a window of opportunity for surgical intervention, whereby if disease progresses on immunotherapy it becomes unresectable. In situations where local therapy is recommended but surgery is not desired, stereotactic radiosurgery may be an effective alternative. The decision-making process regarding upfront surgery versus immunotherapy needs to take place within a specialist melanoma multidisciplinary setting and be customised to individual patient and tumour factors. Ultimately, high-level clinical trial evidence is required to resolve uncertainties in the management of patients with oligometastatic stage IV melanoma but the complexity of the varying presentations may make trial design challenging.

Ipilimumab alone or ipilimumab plus anti-PD-1 therapy in patients with metastatic melanoma resistant to anti-PD-(L)1 monotherapy: a multicentre, retrospective, cohort study

BACKGROUND

Anti-PD-1 therapy (hereafter referred to as anti-PD-1) induces long-term disease control in approximately 30% of patients with metastatic melanoma; however, two-thirds of patients are resistant and will require further treatment. We aimed to determine the efficacy and safety of ipilimumab plus anti-PD-1 (pembrolizumab or nivolumab) compared with ipilimumab monotherapy in patients who are resistant to anti-PD-(L)1 therapy (hereafter referred to as anti-PD-[L]1).

METHODS

This multicentre, retrospective, cohort study, was done at 15 melanoma centres in Australia, Europe, and the USA. We included adult patients (aged ≥18 years) with metastatic melanoma (unresectable stage III and IV), who were resistant to anti-PD-(L)1 (innate or acquired resistance) and who then received either ipilimumab monotherapy or ipilimumab plus anti-PD-1 (pembrolizumab or nivolumab), based on availability of therapies or clinical factors determined by the physician, or both. Tumour response was assessed as per standard of care (CT or PET-CT scans every 3 months). The study endpoints were objective response rate, progression-free survival, overall survival, and safety of ipilimumab compared with ipilimumab plus anti-PD-1.

FINDINGS

We included 355 patients with metastatic melanoma, resistant to anti-PD-(L)1 (nivolumab, pembrolizumab, or atezolizumab), who had been treated with ipilimumab monotherapy (n=162 [46%]) or ipilimumab plus anti-PD-1 (n=193 [54%]) between Feb 1, 2011, and Feb 6, 2020. At a median follow-up of 22·1 months (IQR 9·5-30·9), the objective response rate was higher with ipilimumab plus anti-PD-1 (60 [31%] of 193 patients) than with ipilimumab monotherapy (21 [13%] of 162 patients; p<0·0001). Overall survival was longer in the ipilimumab plus anti-PD-1 group (median overall survival 20·4 months [95% CI 12·7-34·8]) than with ipilimumab monotherapy (8·8 months [6·1-11·3]; hazard ratio [HR] 0·50, 95% CI 0·38-0·66; p<0·0001). Progression-free survival was also longer with ipilimumab plus anti-PD-1 (median 3·0 months [95% CI 2·6-3·6]) than with ipilimumab (2·6 months [2·4-2·9]; HR 0·69, 95% CI 0·55-0·87; p=0·0019). Similar proportions of patients reported grade 3-5 adverse events in both groups (59 [31%] of 193 patients in the ipilimumab plus anti-PD-1 group vs 54 [33%] of 162 patients in the ipilimumab group). The most common grade 3-5 adverse events were diarrhoea or colitis (23 [12%] of 193 patients in the ipilimumab plus anti-PD-1 group vs 33 [20%] of 162 patients in the ipilimumab group) and increased alanine aminotransferase or aspartate aminotransferase (24 [12%] vs 15 [9%]). One death occurred with ipilimumab 26 days after the last treatment: a colon perforation due to immune-related pancolitis.

INTERPRETATION

In patients who are resistant to anti-PD-(L)1, ipilimumab plus anti-PD-1 seemed to yield higher efficacy than ipilimumab with a higher objective response rate, longer progression-free, and longer overall survival, with a similar rate of grade 3-5 toxicity. Ipilimumab plus anti-PD-1 should be favoured over ipilimumab alone as a second-line immunotherapy for these patients with advanced melanoma.

FUNDING

None.

Clinical impact of COVID-19 on patients with cancer treated with immune checkpoint inhibition

Background

Patients with cancer who are infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are more likely to develop severe illness and die compared with those without cancer. The impact of immune checkpoint inhibition (ICI) on the severity of COVID-19 illness is unknown. The aim of this study was to investigate whether ICI confers an additional risk for severe COVID-19 in patients with cancer.

Methods

We analyzed data from 110 patients with laboratory-confirmed SARS-CoV-2 while on treatment with ICI without chemotherapy in 19 hospitals in North America, Europe and Australia. The primary objective was to describe the clinical course and to identify factors associated with hospital and intensive care (ICU) admission and mortality.

Findings

Thirty-five (32%) patients were admitted to hospital and 18 (16%) died. All patients who died had advanced cancer, and only four were admitted to ICU. COVID-19 was the primary cause of death in 8 (7%) patients. Factors independently associated with an increased risk for hospital admission were ECOG ≥2 (OR 39.25, 95% CI 4.17 to 369.2, p=0.0013), treatment with combination ICI (OR 5.68, 95% CI 1.58 to 20.36, p=0.0273) and presence of COVID-19 symptoms (OR 5.30, 95% CI 1.57 to 17.89, p=0.0073). Seventy-six (73%) patients interrupted ICI due to SARS-CoV-2 infection, 43 (57%) of whom had resumed at data cut-off.

Interpretation

COVID-19–related mortality in the ICI-treated population does not appear to be higher than previously published mortality rates for patients with cancer. Inpatient mortality of patients with cancer treated with ICI was high in comparison with previously reported rates for hospitalized patients with cancer and was due to COVID-19 in almost half of the cases. We identified factors associated with adverse outcomes in ICI-treated patients with COVID-19.

Comprehensive analysis of cutaneous and uveal melanoma liver metastases

BACKGROUND

The profound disparity in response to immune checkpoint blockade (ICB) by cutaneous melanoma (CM) and uveal melanoma (UM) patients is not well understood. Therefore, we characterized metastases of CM and UM from the same metastatic site (liver), in order to dissect the potential underlying mechanism in differential response on ICB.

METHODS

Tumor liver samples from CM (n=38) and UM (n=28) patients were analyzed at the genomic (whole exome sequencing), transcriptional (RNA sequencing) and protein (immunohistochemistry and GeoMx Digital Spatial Profiling) level.

RESULTS

Comparison of CM and UM metastases from the same metastatic site revealed that, although originating from the same melanocyte lineage, CM and UM differed in somatic mutation profile, copy number profile, tumor mutational burden (TMB) and consequently predicted neoantigens. A higher melanin content and higher expression of the melanoma differentiation antigen MelanA was observed in liver metastases of UM patients. No difference in B2M and human leukocyte antigen-DR (HLA-DR) expression was observed. A higher expression of programmed cell death ligand 1 (PD-L1) was found in CM compared with UM liver metastases, although the majority of CM and UM liver metastases lacked PD-L1 expression. There was no difference in the extent of immune infiltration observed between CM and UM metastases, with the exception of a higher expression of CD163 (p<0.0001) in CM liver samples. While the extent of immune infiltration was similar for CM and UM metastases, the ratio of exhausted CD8 T cells to cytotoxic T cells, to total CD8 T cells and to Th1 cells, was significantly higher in UM metastases.

CONCLUSIONS

While TMB was different between CM and UM metastases, tumor immune infiltration was similar. The greater dependency on PD-L1 as an immune checkpoint in CM and the identification of higher exhaustion ratios in UM may both serve as explanations for the difference in response to ICB. Consequently, in order to improve current treatment for metastatic UM, reversal of T cell exhaustion beyond programmed cell death 1 blockade should be considered.

Abstract S02-01: Clinical characteristics and outcomes of coronavirus 2019 disease (COVID-19) in cancer patients treated with immune checkpoint inhibitors (ICI)

Background: ICI are widely used in the treatment of various cancer types. It has been hypothesized that ICI could confer an increased risk of severe acute lung injury or other complications associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods: We analyzed data from 113 patients with laboratory-confirmed COVID-19 while on treatment with ICI without chemotherapy in 19 hospitals in North America, Europe, and Australia. Data collected included details on symptoms, comorbidities, medications, treatments and investigations for COVID-19, and outcomes (hospital admission, ICU admission, and mortality).

Results: The median age was 63 years (range 27–86); 40 (35%) patients were female. Most common malignancies were melanoma (n=64, 57%), non-small cell lung cancer (n=19, 17%), and renal cell carcinoma (n=11, 10%); 30 (27%) patients were treated for early (neoadjuvant/adjuvant) and 83 (73%) for advanced cancer. Most patients received anti-PD-1 (n=85, 75%), combination anti-PD-1 and anti-CTLA-4 (n=15, 13%), or anti-PD-L1 (n=8, 7%) ICI. Comorbidities included cardiovascular disease (n=31, 27%), diabetes (n=17, 15%), and pulmonary disease (n=14, 12%). Symptoms were present in 68 (60%) patients; 46 (68%) had fever, 40 (59%) cough, and 23 (34%) dyspnea. Overall, ICI was interrupted in 58 (51%) patients. At data cutoff, 33 (29%) patients were admitted to hospital, 6 (5%) to ICU, and 9 (8%) patients died. COVID-19 was the primary cause of death in 7 patients, 3 of whom were admitted to ICU. Cancer types in patients who died were melanoma (2), non-small cell lung cancer (2), renal cell carcinoma (2), and others (3); all (9) patients had advanced cancer. Administered treatments were oxygen therapy (8), mechanical ventilation (2), vasopression (2), antibiotics (7), antiviral drugs (4), glucocorticoids (2), and anti-IL-6 (2). Of all hospitalized patients, 20 (61%) had been discharged and 4 (12%) were still in hospital at data cutoff.

Conclusion: The mortality rate of COVID-19 in patients on ICI is higher than rates reported for the general population without comorbidities but may not be higher than rates reported for the cancer population. Despite these preliminary findings, COVID-19 patients on ICI may not have symptoms and a proportion may continue ICI. Correlative analyses are ongoing and will be presented.

Citation Format: Aljosja Rogiers, Carlo Tondini, Joe M. Grimes, Megan H. Trager, Sharon Nahm, Leyre Zubiri, Neha Papneja, Arielle Elkrief, Jessica Borgers, April Rose, Johanna Mangana, Michael Erdmann, Ines Pires da Silva, Christian Posch, Axel Hauschild, Lisa Zimmer, Paola Queirolo, Caroline Robert, Karijn Suijkerbuijk, Paolo A. Ascierto, Paul Lorigan, Richard Carvajal, Osama E Rahma, Mario Mandala, Georgina V. Long. Clinical characteristics and outcomes of coronavirus 2019 disease (COVID-19) in cancer patients treated with immune checkpoint inhibitors (ICI) [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2020 Jul 20-22. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(18_Suppl):Abstract nr S02-01.

Incidence, features and management of radionecrosis in melanoma patients treated with cerebral radiotherapy and anti-PD-1 antibodies

BACKGROUND

Brain radiotherapy is used in the management of melanoma brain metastases (MBM) and can result in radionecrosis. Anti-PD-1 is active in the brain and may increase the risk of radionecrosis when combined with radiotherapy. We studied the incidence, associated factors and management of radionecrosis in longer-term survivors with MBM treated with this combination.

METHODS

Patients with MBM treated with radiotherapy and anti-PD-1 who survived >1 year were identified to determine radionecrosis incidence (Cohort A, n = 135). Cohort A plus additional radionecrosis cases were examined for factors associated with radionecrosis and management (Cohort B, n = 148).

RESULTS

From Cohort A, 17% developed radionecrosis, with a cumulative incidence at 2 years of 18%. Using Cohort B, multivariable analysis confirmed an association between radionecrosis and elevated lactate dehydrogenase (p = 0.0496) and prior treatment with ipilimumab (p = 0.0319). Radionecrosis was diagnosed based on MRI (100%), symptoms (69%) and pathology (56%). Treatment included corticosteroids, bevacizumab and neurosurgery.

CONCLUSIONS

Radionecrosis is a significant toxicity in longer-term melanoma survivors with MBM treated with anti-PD-1 and radiotherapy. Identification of those at risk of radionecrosis who may avoid radiotherapy is required.

Distinct Immune Cell Populations Define Response to Anti-PD-1 Monotherapy and Anti-PD-1/Anti-CTLA-4 Combined Therapy

Cancer immunotherapies provide survival benefits in responding patients, but many patients fail to respond. Identifying the biology of treatment response and resistance are a priority to optimize drug selection and improve patient outcomes. We performed transcriptomic and immune profiling on 158 tumor biopsies from melanoma patients treated with anti-PD-1 monotherapy (n = 63) or combined anti-PD-1 and anti-CTLA-4 (n = 57). These data identified activated T cell signatures and T cell populations in responders to both treatments. Further mass cytometry analysis identified an EOMES⁺CD69⁺CD45RO⁺ effector memory T cell phenotype that was significantly more abundant in responders to combined immunotherapy compared with non-responders (n = 18). The gene expression profile of this population was associated with longer progression-free survival in patients treated with single agent and greater tumor shrinkage in both treatments.

Melanoma expression of matrix metalloproteinase-23 is associated with blunted tumor immunity and poor responses to immunotherapy

BACKGROUND

Matrix metalloproteinase-23 (MMP-23) can block the voltage-gated potassium channel Kv1.3, whose function is important for sustained Ca(2+) signaling during T cell activation. MMP-23 may also alter T cell activity and phenotype through cleavage of proteins affecting cytokine and chemokine signaling. We therefore tested the hypothesis that MMP-23 can negatively regulate the anti-tumor T cell response in human melanoma.

METHODS

We characterized MMP-23 expression in primary melanoma patients who received adjuvant immunotherapy. We examined the association of MMP-23 with the anti-tumor immune response - as assessed by the prevalence of tumor-infiltrating lymphocytes and Foxp3(+) regulatory T cells. Further, we examined the association between MMP-23 expression and response to immunotherapy. Considering also an in trans mechanism, we examined the association of melanoma MMP-23 and melanoma Kv1.3 expression.

RESULTS

Our data revealed an inverse association between primary melanoma MMP-23 expression and the anti-tumor T cell response, as demonstrated by decreased tumor-infiltrating lymphocytes (TIL) (P = 0.05), in particular brisk TILs (P = 0.04), and a trend towards an increased proportion of immunosuppressive Foxp3(+) regulatory T cells (P = 0.07). High melanoma MMP-23 expression is also associated with recurrence in patients treated with immune biologics (P = 0.037) but not in those treated with vaccines (P = 0.64). Further, high melanoma MMP-23 expression is associated with shorter periods of progression-free survival for patients receiving immune biologics (P = 0.025). On the other hand, there is no relationship between melanoma MMP-23 and melanoma Kv1.3 expression (P = 0.27).

CONCLUSIONS

Our data support a role for MMP-23 as a potential immunosuppressive target in melanoma, as well as a possible biomarker for informing melanoma immunotherapies.

Reversal of NK-cell exhaustion in advanced melanoma by Tim-3 blockade

The immunoregulatory protein T-cell immunoglobulin- and mucin-domain-containing molecule-3 (Tim-3) mediates T-cell exhaustion and contributes to the suppression of immune responses in both viral infections and tumors. Tim-3 blockade reverses the exhausted phenotype of CD4+ and CD8+ T cells in several chronic diseases, including melanoma. Interestingly, natural killer (NK) cells constitutively express Tim-3; however, the role of Tim-3 in modulating the function of these innate effector cells remains unclear, particularly in human diseases. In this study, we compared the function of Tim-3 in NK cells from healthy donors and patients with metastatic melanoma. NK cells from the latter were functionally impaired/exhausted, and Tim-3 blockade reversed this exhausted phenotype. Moreover, Tim-3 expression levels were correlated with the stage of the disease and poor prognostic factors. These data indicate that Tim-3 can function as an NK-cell exhaustion marker in advanced melanoma and support the development of Tim-3-targeted therapies to restore antitumor immunity.