Autologous human preclinical modeling of melanoma interpatient clinical responses to immunotherapeutics

BACKGROUND

Despite recent advances in immunotherapy, a substantial population of late-stage melanoma patients still fail to achieve sustained clinical benefit. Lack of translational preclinical models continues to be a major challenge in the field of immunotherapy; thus, more optimized translational models could strongly influence clinical trial development. To address this unmet need, we designed a preclinical model reflecting the heterogeneity in melanoma patients' clinical responses that can be used to evaluate novel immunotherapies and synergistic combinatorial treatment strategies. Using our all-autologous humanized melanoma mouse model, we examined the efficacy of a novel engineered interleukin 2 (IL-2)-based cytokine variant immunotherapy.

METHODS

To study immune responses and antitumor efficacy for human melanoma tumors, we developed an all-autologous humanized melanoma mouse model using clinically annotated, matched patient tumor cells and peripheral blood mononuclear cells (PBMCs). After inoculating immunodeficient NSG mice with patient tumors and an adoptive cell transfer of autologous PBMCs, mice were treated with anti-PD-1, a novel investigational engineered IL-2-based cytokine (nemvaleukin), or recombinant human IL-2 (rhIL-2). The pharmacodynamic effects and antitumor efficacy of these treatments were then evaluated. We used tumor cells and autologous PBMCs from patients with varying immunotherapy responses to both model the diversity of immunotherapy efficacy observed in the clinical setting and to recapitulate the heterogeneous nature of melanoma.

RESULTS

Our model exhibited long-term survival of engrafted human PBMCs without developing graft-versus-host disease. Administration of an anti-PD-1 or nemvaleukin elicited antitumor responses in our model that were patient-specific and were found to parallel clinical responsiveness to checkpoint inhibitors. An evaluation of nemvaleukin-treated mice demonstrated increased tumor-infiltrating CD4+ and CD8+ T cells, preferential expansion of non-regulatory T cell subsets in the spleen, and significant delays in tumor growth compared with vehicle-treated controls or mice treated with rhIL-2.

CONCLUSIONS

Our model reproduces differential effects of immunotherapy in melanoma patients, capturing the inherent heterogeneity in clinical responses. Taken together, these data demonstrate our model's translatability for novel immunotherapies in melanoma patients. The data are also supportive for the continued clinical investigation of nemvaleukin as a novel immunotherapeutic for the treatment of melanoma.

Perspectives in Melanoma: meeting report from the Melanoma Bridge (December 1st-3rd, 2022-Naples, Italy)

Outcomes for patients with melanoma have improved over the past decade with the clinical development and approval of immunotherapies targeting immune checkpoint receptors such as programmed death-1 (PD-1), programmed death ligand 1 (PD-L1) or cytotoxic T lymphocyte antigen-4 (CTLA-4). Combinations of these checkpoint therapies with other agents are now being explored to improve outcomes and enhance benefit-risk profiles of treatment. Alternative inhibitory receptors have been identified that may be targeted for anti-tumor immune therapy, such as lymphocyte-activation gene-3 (LAG-3), as have several potential target oncogenes for molecularly targeted therapy, such as tyrosine kinase inhibitors. Unfortunately, many patients still progress and acquire resistance to immunotherapy and molecularly targeted therapies. To bypass resistance, combination treatment with immunotherapies and single or multiple TKIs have been shown to improve prognosis compared to monotherapy. The number of new combinations treatment under development for melanoma provides options for the number of patients to achieve a therapeutic benefit. Many diagnostic and prognostic assays have begun to show clinical applicability providing additional tools to optimize and individualize treatments. However, the question on the optimal algorithm of first- and later-line therapies and the search for biomarkers to guide these decisions are still under investigation. This year, the Melanoma Bridge Congress (Dec 1st-3rd, 2022, Naples, Italy) addressed the latest advances in melanoma research, focusing on themes of paramount importance for melanoma prevention, diagnosis and treatment. This included sessions dedicated to systems biology on immunotherapy, immunogenicity and gene expression profiling, biomarkers, and combination treatment strategies.

Fluctuations in Gut Microbiome Composition During Immune Checkpoint Inhibitor Therapy

Background

Immune checkpoint inhibitors (ICIs) such as programmed cell death protein-1 (PD-1) inhibitors or PD-1 ligand-1 (PD-L1) inhibitors have led to remarkable improvement in outcomes of non-small cell lung cancer (NSCLC). Unfortunately, the significant benefits of ICI therapy are frequently limited by resistance to treatment and adverse effects, and the predictive value of pre-treatment tumor tissue PD-L1 expression is limited. Development of less invasive biomarkers that could identify responders and non-responders in early on-treatment could markedly improve the treatment regimen. Accumulating evidence suggests that baseline gut microbiota profile is associated with response to PD-1/PD-L1 blockade therapy. However, change in the gut microbiome composition during PD-1/PD-L1 blockade therapy and its relation to response remain unclear.

Methods

Here, we analyzed pre- and on-treatment fecal samples from five NSCLC patients receiving anti-PD-1 immunotherapy, alone or in tandem with chemotherapy, and performed 16S rRNA sequencing.

Results

The overall alpha diversity of the baseline gut microbiome was similar between three responders and two non-responders. While the gut microbiome composition remained stable overall during treatment (R2 = 0.145), responders showed significant changes in microbiome diversity between pre- and on-treatment samples during anti-PD-1 therapy compared to non-responders (P = 0.0274). Within the diverse microbiota, responders showed decreases in the abundance of genera Odoribacter, Gordonibacter, Candidatus Stoquefichus, Escherichia-Shigella, and Collinsella, and increase in abundance of Clostridium sensu stricto 1. In contrast, non-responders demonstrated on-treatment increases in genera Prevotella, Porphyromonas, Streptococcus, and Escherichia-Shigella, and decrease in abundance of Akkermansia.

Conclusions

This pilot study identified a substantial change in gut microbiome diversity between pre- and on-treatment samples in NSCLC patients responding to anti-PD-1 therapy compared to non-responders. Our findings highlight the potential utility of gut microbiota dynamics as a noninvasive biomarker to predict response to PD-1/PD-L1 blockade therapy for a wide variety of malignancies, which sets a path for future investigation in larger prospective studies.

A phase II study of alternating sunitinib and temsirolimus therapy in patients with metastatic renal cell carcinoma

BACKGROUND

Sunitinib is a multi-target tyrosine kinase inhibitor (TKI) that inhibits VEGF receptor 1, 2, 3 (VEGFRs), platelet-derived growth factor receptor (PDGFR), colony-stimulating factor receptor (CSFR), and the stem cell factor receptor c-KIT. Temsirolimus inhibits mammalian target of rapamycin (mTOR) through binding to intracellular protein FKBP-12. Both agents are approved for the treatment of metastatic renal cell carcinoma (mRCC), have different anticancer mechanisms, and non-overlapping toxicities. These attributes form the scientific rationale for sequential combination of these agents. The primary objective of the study was to investigate the efficacy of alternating sunitinib and temsirolimus therapy on progression-free survival (PFS) in mRCC.

METHODS

We undertook a phase II, multi-center, single cohort, open-label study in patients with mRCC. Patients were treated with alternating dosing of 4 weeks of sunitinib 50 mg PO daily, followed by 2 weeks rest, then 4 weeks of temsirolimus 25 mg IV weekly, followed by 2 weeks rest (12 weeks total per cycle). The primary endpoint was PFS. Secondary endpoints included clinical response rate and characterization of the toxicity profile of this combination therapy.

RESULTS

Nineteen patients were enrolled into the study. The median observed PFS (n = 13 evaluable for PFS) was 8.8 months (95% CI 6.8-25.2 months). Best responses achieved were five partial response, nine stable disease, and three disease progression according to RECIST 1.1 guidelines (two non-evaluable). The most commonly observed toxicities were fatigue, platelet count decrease, creatinine increased, diarrhea, oral mucositis, edema, anemia, rash, hypophosphatemia, dysgeusia, and palmar-plantar erythrodysesthesia syndrome.

CONCLUSION

Alternating sunitinib and temsirolimus did not improve the PFS in patients with mRCC.

Pathway Alterations in Stage II/III Primary Melanoma

PURPOSE

Genomic classification of melanoma has thus far focused on the mutational status of BRAF, NRAS, and NF1. The clinical utility of this classification remains limited, and the landscape of alterations in other oncogenic signaling pathways is underexplored.

METHODS

Using primary samples from the InterMEL study, a retrospective cohort of cases with specimens collected from an international consortium with participating institutions throughout the United States and Australia, with oversampling of cases who ultimately died of melanoma, we examined mutual exclusivity and co-occurrence of genomic alterations in 495 stage II/III primary melanomas across 11 cancer pathways. Somatic mutation and copy number alterations were analyzed from next-generation sequencing using a clinical sequencing panel.

RESULTS

Mutations in the RTK-RAS pathway were observed in 81% of cases. Other frequently occurring pathways were TP53 (31%), Cell Cycle (30%), and PI3K (18%). These frequencies are generally lower than was observed in The Cancer Genome Atlas, where the specimens analyzed were predominantly obtained from metastases. Overall, 81% of the cases had at least one targetable mutation. The RTK-RAS pathway was the only pathway that demonstrated strong and statistically significant mutual exclusivity. However, this strong mutual exclusivity signal was evident only for the three common genes in the pathway (BRAF, NRAS, and NF1). Analysis of co-occurrence of different pathways exhibited no positive significant trends. However, interestingly, a high frequency of cases with none of these pathways represented was observed, 8.4% of cases versus 4.0% expected (P < .001). A higher frequency of RTK-RAS singletons (with no other pathway alteration) was observed compared with The Cancer Genome Atlas. Clonality analyses suggest strongly that both the cell cycle and RTK-RAS pathways represent early events in melanogenesis.

CONCLUSION

Our results confirm the dominance of mutations in the RTK-RAS pathway. The presence of many mutations in several well-known, actionable pathways suggests potential avenues for targeted therapy in these early-stage cases.

Methylation of nonessential genes in cutaneous melanoma - Rule Out hypothesis

Differential methylation plays an important role in melanoma development and is associated with survival, progression and response to treatment. However, the mechanisms by which methylation promotes melanoma development are poorly understood. The traditional explanation of selective advantage provided by differential methylation postulates that hypermethylation of regulatory 5'-cytosine-phosphate-guanine-3' dinucleotides (CpGs) downregulates the expression of tumor suppressor genes and therefore promotes tumorigenesis. We believe that other (not necessarily alternative) explanations of the selective advantages of methylation are also possible. Here, we hypothesize that melanoma cells use methylation to shut down transcription of nonessential genes - those not required for cell survival and proliferation. Suppression of nonessential genes allows tumor cells to be more efficient in terms of energy and resource usage, providing them with a selective advantage over the tumor cells that transcribe and subsequently translate genes they do not need. We named the hypothesis the Rule Out (RO) hypothesis. The RO hypothesis predicts higher methylation of CpGs located in regulatory regions (CpG islands) of nonessential genes. It also predicts the higher methylation of regulatory CpGs linked to nonessential genes in melanomas compared to nevi and lower expression of nonessential genes in malignant (derived from melanoma) versus normal (derived from nonaffected skin) melanocytes. The analyses conducted using in-house and publicly available data found that all predictions derived from the RO hypothesis hold, providing observational support for the hypothesis.

Interferon Alfa-2b Adjuvant Therapy of High-Risk Resected Cutaneous Melanoma: The Eastern Cooperative Oncology Group Trial EST 1684

PURPOSE

Interferon alfa-2b (IFN alpha-2b) exhibits antitumor activity in metastatic melanoma and on this basis has been evaluated as an adjuvant therapy following surgery for deep primary (T4) or regionally metastatic (N1) melanoma.

METHODS

A randomized controlled study of IFN alpha-2b (Schering-Plough, Kenilworth, NJ) administered at maximum-tolerated doses of 20 MU/m2/d intravenously (i.v.) for 1 month and 10 MU/m2 three times per week subcutaneously (SC) for 48 weeks versus observation, was conducted by the Eastern Cooperative Oncology Group (ECOG) in 287 patients.

RESULTS

A significant prolongation of relapse-free survival (P = .0023, one-sided) and prolongation of overall survival (P = .0237, one-sided) was observed with IFN alpha-2b therapy in this trial, which is now mature with a median follow-up time of 6.9 years. The impact of treatment on relapse rate is most pronounced early during the treatment interval. The overall benefit of treatment in this trial was analyzed stratified by tumor burden and the presence or absence of microscopic nonpalpable and palpable regional lymph node metastasis. The benefit of therapy with IFN alpha-2b was greatest among node-positive strata. Toxicity of IFN alpha-2b required dose modification in the majority of patients, but treatment at > or = 80% of the scheduled dose was feasible in the majority of patients through the IV phase of treatment, and for more than 3 months of SC maintenance therapy. Discontinuation of treatment due to toxicity was infrequent after the fourth month of therapy.

CONCLUSION

IFN alpha-2b prolongs the relapse-free interval and overall survival of high-risk resected melanoma patients. The increment in median disease-free survival (from 1 to 1.7 years) and overall survival (from 2.8 to 3.8 years) that results from this therapy is associated with a 42% improvement in the fraction of patients who are continuously disease-free after treatment with IFN (from 26% to 37%) in comparison to observation. IFN alpha-2b is the first agent to show a significant benefit in relapse-free and overall survival of high-risk melanoma patients in a randomized controlled trial.

Targeting the secreted RGDKGE collagen fragment reduces PD‑L1 by a proteasome‑dependent mechanism and inhibits tumor growth

Structural alterations of collagen impact signaling that helps control tumor progression and the responses to therapeutic intervention. Integrins represent a class of receptors that include members that mediate collagen signaling. However, a strategy of directly targeting integrins to control tumor growth has demonstrated limited activity in the clinical setting. New molecular understanding of integrins have revealed that these receptors can regulate both pro‑ and anti‑tumorigenic functions in a cell type‑dependent manner. Therefore, designing strategies that block pro‑tumorigenic signaling, without impeding anti‑tumorigenic functions, may lead to development of more effective therapies. In the present study, evidence was provided for a novel signaling cascade in which β3‑integrin‑mediated binding to a secreted RGDKGE‑containing collagen fragment stimulates an autocrine‑like signaling pathway that differentially governs the activity of both YAP and (protein kinase‑A) PKA, ultimately leading to alterations in the levels of immune checkpoint molecule PD‑L1 by a proteasome dependent mechanism. Selectively targeting this collagen fragment, reduced nuclear YAP levels, and enhanced PKA and proteasome activity, while also exhibiting significant antitumor activity in vivo. The present findings not only provided new mechanistic insight into a previously unknown autocrine‑like signaling pathway that may provide tumor cells with the ability to regulate PD‑L1, but our findings may also help in the development of more effective strategies to control pro‑tumorigenic β3‑integrin signaling without disrupting its tumor suppressive functions in other cellular compartments.

InterMEL: An international biorepository and clinical database to uncover predictors of survival in early-stage melanoma

INTRODUCTION

We are conducting a multicenter study to identify classifiers predictive of disease-specific survival in patients with primary melanomas. Here we delineate the unique aspects, challenges, and best practices for optimizing a study of generally small-sized pigmented tumor samples including primary melanomas of at least 1.05mm from AJTCC TNM stage IIA-IIID patients. We also evaluated tissue-derived predictors of extracted nucleic acids' quality and success in downstream testing. This ongoing study will target 1,000 melanomas within the international InterMEL consortium.

METHODS

Following a pre-established protocol, participating centers ship formalin-fixed paraffin embedded (FFPE) tissue sections to Memorial Sloan Kettering Cancer Center for the centralized handling, dermatopathology review and histology-guided coextraction of RNA and DNA. Samples are distributed for evaluation of somatic mutations using next gen sequencing (NGS) with the MSK-IMPACTTM assay, methylation-profiling (Infinium MethylationEPIC arrays), and miRNA expression (Nanostring nCounter Human v3 miRNA Expression Assay).

RESULTS

Sufficient material was obtained for screening of miRNA expression in 683/685 (99%) eligible melanomas, methylation in 467 (68%), and somatic mutations in 560 (82%). In 446/685 (65%) cases, aliquots of RNA/DNA were sufficient for testing with all three platforms. Among samples evaluated by the time of this analysis, the mean NGS coverage was 249x, 59 (18.6%) samples had coverage below 100x, and 41/414 (10%) failed methylation QC due to low intensity probes or insufficient Meta-Mixed Interquartile (BMIQ)- and single sample (ss)- Noob normalizations. Six of 683 RNAs (1%) failed Nanostring QC due to the low proportion of probes above the minimum threshold. Age of the FFPE tissue blocks (p<0.001) and time elapsed from sectioning to co-extraction (p = 0.002) were associated with methylation screening failures. Melanin reduced the ability to amplify fragments of 200bp or greater (absent/lightly pigmented vs heavily pigmented, p<0.003). Conversely, heavily pigmented tumors rendered greater amounts of RNA (p<0.001), and of RNA above 200 nucleotides (p<0.001).

CONCLUSION

Our experience with many archival tissues demonstrates that with careful management of tissue processing and quality control it is possible to conduct multi-omic studies in a complex multi-institutional setting for investigations involving minute quantities of FFPE tumors, as in studies of early-stage melanoma. The study describes, for the first time, the optimal strategy for obtaining archival and limited tumor tissue, the characteristics of the nucleic acids co-extracted from a unique cell lysate, and success rate in downstream applications. In addition, our findings provide an estimate of the anticipated attrition that will guide other large multicenter research and consortia.

Landscape of mutations in early stage primary cutaneous melanoma: An InterMEL study

It is unclear why some melanomas aggressively metastasize while others remain indolent. Available studies employing multi-omic profiling of melanomas are based on large primary or metastatic tumors. We examine the genomic landscape of early-stage melanomas diagnosed prior to the modern era of immunological treatments. Untreated cases with Stage II/III cutaneous melanoma were identified from institutions throughout the United States, Australia and Spain. FFPE tumor sections were profiled for mutation, methylation and microRNAs. Preliminary results from mutation profiling and clinical pathologic correlates show the distribution of four driver mutation sub-types: 31% BRAF; 18% NRAS; 21% NF1; 26% Triple Wild Type. BRAF mutant tumors had younger age at diagnosis, more associated nevi, more tumor infiltrating lymphocytes, and fewer thick tumors although at generally more advanced stage. NF1 mutant tumors were frequent on the head/neck in older patients with severe solar elastosis, thicker tumors but in earlier stages. Triple Wild Type tumors were predominantly male, frequently on the leg, with more perineural invasion. Mutations in TERT, TP53, CDKN2A and ARID2 were observed often, with TP53 mutations occurring particularly frequently in the NF1 sub-type. The InterMEL study will provide the most extensive multi-omic profiling of early-stage melanoma to date. Initial results demonstrate a nuanced understanding of the mutational and clinicopathological landscape of these early-stage tumors.

Perspectives in Melanoma: meeting report from the Melanoma Bridge (December 2nd - 4th, 2021, Italy)

Advances in immune checkpoint and combination therapy have led to improvement in overall survival for patients with advanced melanoma. Improved understanding of the tumor, tumor microenvironment and tumor immune-evasion mechanisms has resulted in new approaches to targeting and harnessing the host immune response. Combination modalities with other immunotherapy agents, chemotherapy, radiotherapy, electrochemotherapy are also being explored to overcome resistance and to potentiate the immune response. In addition, novel approaches such as adoptive cell therapy, oncogenic viruses, vaccines and different strategies of drug administration including sequential, or combination treatment are being tested. Despite the progress in diagnosis of melanocytic lesions, correct classification of patients, selection of appropriate adjuvant and systemic theràapies, and prediction of response to therapy remain real challenges in melanoma. Improved understanding of the tumor microenvironment, tumor immunity and response to therapy has prompted extensive translational and clinical research in melanoma. There is a growing evidence that genomic and immune features of pre-treatment tumor biopsies may correlate with response in patients with melanoma and other cancers, but they have yet to be fully characterized and implemented clinically. Development of novel biomarker platforms may help to improve diagnostics and predictive accuracy for selection of patients for specific treatment. Overall, the future research efforts in melanoma therapeutics and translational research should focus on several aspects including: (a) developing robust biomarkers to predict efficacy of therapeutic modalities to guide clinical decision-making and optimize treatment regimens, (b) identifying mechanisms of therapeutic resistance to immune checkpoint inhibitors that are potentially actionable, (c) identifying biomarkers to predict therapy-induced adverse events, and (d) studying mechanism of actions of therapeutic agents and developing algorithms to optimize combination treatments. During the Melanoma Bridge meeting (December 2nd-4th, 2021, Naples, Italy) discussions focused on the currently approved systemic and local therapies for advanced melanoma and discussed novel biomarker strategies and advances in precision medicine as well as the impact of COVID-19 pandemic on management of melanoma patients.

Maximizing the value of phase III trials in immuno-oncology: A checklist from the Society for Immunotherapy of Cancer (SITC)

The broad activity of agents blocking the programmed cell death protein 1 and its ligand (the PD-(L)1 axis) revolutionized oncology, offering long-term benefit to patients and even curative responses for tumors that were once associated with dismal prognosis. However, only a minority of patients experience durable clinical benefit with immune checkpoint inhibitor monotherapy in most disease settings. Spurred by preclinical and correlative studies to understand mechanisms of non-response to the PD-(L)1 antagonists and by combination studies in animal tumor models, many drug development programs were designed to combine anti-PD-(L)1 with a variety of approved and investigational chemotherapies, tumor-targeted therapies, antiangiogenic therapies, and other immunotherapies. Several immunotherapy combinations improved survival outcomes in a variety of indications including melanoma, lung, kidney, and liver cancer, among others. This immunotherapy renaissance, however, has led to many combinations being advanced to late-stage development without definitive predictive biomarkers, limited phase I and phase II data, or clinical trial designs that are not optimized for demonstrating the unique attributes of immune-related antitumor activity-for example, landmark progression-free survival and overall survival. The decision to activate a study at an individual site is investigator-driven, and generalized frameworks to evaluate the potential for phase III trials in immuno-oncology to yield positive data, particularly to increase the number of curative responses or otherwise advance the field have thus far been lacking. To assist in evaluating the potential value to patients and the immunotherapy field of phase III trials, the Society for Immunotherapy of Cancer (SITC) has developed a checklist for investigators, described in this manuscript. Although the checklist focuses on anti-PD-(L)1-based combinations, it may be applied to any regimen in which immune modulation is an important component of the antitumor effect.

Abstract CT568: β-2 adrenergic receptor (AR): Another immune checkpoint (IC)" A phase II clinical trial of propranolol (P) with pembrolizumab (Pem) in patients with unresectable stage III and stage IV melanoma

Background: Adrenergic stress (AS) reduces anti-tumor response by decreasing the frequency and function of CD8+ T- cells in the tumor microenvironment (TME), resulting in an increase in those with an “exhausted” phenotype.1 Additionally, AS increases the quantity and immunosuppressive phenotype of myeloid-derived suppressor cells (MDSC) in the TME.2 The data above suggests that β-2 AR acts akin to a tumorigenic IC which can be abrogated by using P, a well-known and highly cost efficient non-selective β-blocker. Synergistic activity of anti-PD-1 with P has been reported in several murine tumor models, including the B-16 OVA mouse model.3,4 A retrospective study has shown an improvement in overall survival (OS) in patients (pts) with metastatic melanoma (MM) treated concurrently with non-selective β-blocker and immunotherapy.5 This formed the basis for our phase I study of the combination of P (at dose levels; 10 mg, 20 mg BID, and 30mg BID) and pem 200 mg every 3 weeks in pts with MM. Our published phase I results found all 3 dose levels of P to be well tolerated, and an objective response was observed in 7/9 pts.6 A decrease in perceived stress score (PSS) in pts over time was observed. Intra-tumor ratio of (CD4+T cells + CD8+T-cells)/(MDSC+ Treg) &gt;1 in the pre-treatment biopsy was predictive of treatment response. Based on the results of the phase I study, we chose P 30 mg BID as the recommended phase II dose. These results, though preliminary, strongly support our subsequent phase II clinical trial.

Methods: In this prospective, single-arm, phase II, multicenter trial, pts with unresectable stage III/IV MM and measurable disease per RECIST v1.1 will be treated with P (30 mg BID) + Pem. Pts with active CNS disease, prior therapy with PD-1/PD-L1 inhibitors, or contraindications to β-blocker are excluded. The primary objective is to evaluate the overall response rate (ORR) by immune-modified RECIST v1.1. The secondary objectives are the assessment of progression free survival and OS. A Simon two-stage design will be employed, requiring a minimum of 29 pts (17 in stage 1 and 12 in stage 2) to achieve approximately 80% power to detect a 20% increase (0.35 to 0.55) in the ORR. As an exploratory analysis, we will further report a) Baseline and on-treatment PSS and b) Chronotropic effect of P after 5-minute treadmill walk as a biomarker of response; c) Post therapy changes in the TME, with a 12 week on therapy optional biopsy d) Peripheral blood changes in T cell and MDSC subsets, and cytokines/chemokines. To date, 10 pts have been accrued on the study (NCT0384836).

Citation Format: Benjamin Switzer, Manu R. Pandey, Alexandra Valentine, Agnieszka Witkiewicz, Erik Knudsen, Kristopher Attwood, Joseph Tario, Pauline Funchain, Joseph J. Drabick, Hemn Mohammadpour, Marc S. Ernstoff, Igor Puzanov, Elizabeth A. Repasky, Shipra Gandhi. β-2 adrenergic receptor (AR): Another immune checkpoint (IC)" A phase II clinical trial of propranolol (P) with pembrolizumab (Pem) in patients with unresectable stage III and stage IV melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT568.

Nemvaleukin alfa monotherapy and in combination with pembrolizumab in patients (pts) with advanced solid tumors: ARTISTRY-1

2500

Background: Nemvaleukin alfa (nemvaleukin, ALKS 4230) is a novel, engineered cytokine that selectively binds to the intermediate-affinity interleukin-2 (IL-2) receptor (IL-2R) to preferentially activate antitumor CD8+ T cells and natural killer (NK) cells with minimal expansion of immunosuppressive regulatory T cells. It is sterically occluded from binding to the high-affinity IL-2R, leveraging antitumor effects of the IL-2 pathway but mitigating toxicity associated with preferential binding of IL-2 to the high-affinity IL-2R. Methods: ARTISTRY-1 (NCT02799095) is a 3-part, first-in-human, phase 1/2 study of IV nemvaleukin alone and in combination with pembrolizumab in pts with advanced solid tumors. Parts A (dose escalation to 10 µg/kg/day), B (monotherapy in pts with melanoma or renal cell carcinoma [RCC]), and C (combination) included nemvaleukin 3 or 6 µg/kg/day ´ 5 and pembrolizumab every 21 days. Investigator-assessed antitumor activity (confirmed responses as per RECIST v1.1) and safety are reported as of 29 October 2021. Results: In Part A (N = 46), nemvaleukin recommended phase 2 dose was 6 µg/kg/day IV; maximum tolerated dose not reached. One pt had dose-limiting toxicity (grade 4 acute kidney injury) at 10 µg/kg. Pts in Parts B and C were heavily pretreated (1–9 prior lines of therapy, including prior checkpoint inhibitor therapy). Durable antitumor activity was observed for nemvaleukin monotherapy, including in RCC (objective response rate [ORR], 18.2% [4/22]) and in melanoma (ORR, 8.7% [4/46]), with 2 partial responses (1 unconfirmed) in 30 pts with cutaneous melanoma (ORR, 6.7%) and 2 PRs (1 unconfirmed) in 6 pts with mucosal melanoma (ORR, 33.3%). Durable antitumor activity was also observed for combination therapy (ORR, 16.1% [22/137]; disease control rate [DCR], 59.9%), including in platinum-resistant ovarian cancer (PROC; ORR, 28.6% [4/14]; DCR, 71.4%), with 2 complete responses and 2 PRs (1 unconfirmed) in 14 pts. Forty-three pts remain on therapy. The most frequent grade 3/4 treatment-related adverse events in Parts B and C, respectively, were anemia (9%, 10%), neutropenia (34%, 9%), and decreased neutrophil count (12%, 9%). Safety was consistent with previous reports. In pharmacodynamic studies, nemvaleukin monotherapy induced robust expansion of CD8+ T and NK cells, with minimal effect on regulatory T cells. Conclusions: ARTISTRY-1 showed proof of principle for preferential expansion of CD8+ T cells and NK cells by nemvaleukin. Nemvaleukin was generally well tolerated and demonstrated promising efficacy. Durable responses were observed with monotherapy and combination therapy in heavily pretreated pts across a range of tumors, warranting further investigation. The US FDA granted nemvaleukin Fast Track designation for treatment of mucosal melanoma and PROC, and Orphan Drug designation for mucosal melanoma. Clinical trial information: NCT02799095.

Managing Metastatic Melanoma in 2022: A Clinical Review

Cutaneous melanoma remains the most lethal of the primary cutaneous neoplasms, and although the incidence of primary melanoma continues to rise, the mortality from metastatic disease remains unchanged, in part through advances in treatment. Major developments in immunomodulatory and targeted therapies have provided robust improvements in response and survival trends that have transformed the clinical management of patients with metastatic melanoma. Additional advances in immunologic and cancer cell biology have contributed to further optimization in (1) risk stratification, (2) prognostication, (3) treatment, (4) toxicity management, and (5) surveillance approaches for patients with an advanced melanoma diagnosis. In this review, we provide a comprehensive overview of the historical and future advances regarding the translational and clinical implications of advanced melanoma and share multidisciplinary recommendations to aid clinicians in the navigation of current treatment approaches for a variety of patient cohorts.

Efficacy and safety of vedolizumab and infliximab treatment for immune-mediated diarrhea and colitis in patients with cancer: a two-center observational study

Background

Current treatment guidelines for immune-mediated diarrhea and colitis (IMDC) recommend steroids as first-line therapy, followed by selective immunosuppressive therapy (SIT) (infliximab or vedolizumab) for refractory cases. We aimed to compare the efficacy of these two SITs and their impact on cancer outcomes.

Methods

We performed a two-center, retrospective observational cohort study of patients with IMDC who received SITs following steroids from 2016 to 2020. Patients’ demographic, clinical, and overall survival data were collected and analyzed.

Results

A total of 184 patients (62 vedolizumab, 94 infliximab, 28 combined sequentially) were included. The efficacy of achieving clinical remission of IMDC was similar (89% vs 88%, p=0.79) between the two groups. Compared with the infliximab group, the vedolizumab group had a shorter steroid exposure (35 vs 50 days, p<0.001), fewer hospitalizations (16% vs 28%, p=0.005), and a shorter hospital stay (median 10.5 vs 13.5 days, p=0.043), but a longer time to clinical response (17.5 vs 13 days, p=0.012). Longer durations of immune checkpoint inhibitors treatment (OR 1.01, p=0.004) and steroid use (OR 1.02, p=0.043), and infliximab use alone (OR 2.51, p=0.039) were associated with higher IMDC recurrence. Furthermore, ≥3 doses of SIT (p=0.011), and fewer steroid tapering attempts (p=0.012) were associated with favorable overall survival.

Conclusions

Treatment with vedolizumab as compared with infliximab for IMDC led to comparable IMDC response rates, shorter duration of steroid use, fewer hospitalizations, and lower IMDC recurrence, though with slightly longer time to IMDC response. Higher number of SIT doses was associated with better survival outcome, while more steroid exposure resulted in worse patient outcomes.

Long-term outcomes of patients with active melanoma brain metastases treated with combination nivolumab plus ipilimumab (CheckMate 204): final results of an open-label, multicentre, phase 2 study

BACKGROUND

Combination nivolumab plus ipilimumab was efficacious in patients with asymptomatic melanoma brain metastases (MBM) in CheckMate 204, but showed low efficacy in patients with symptomatic MBM. Here, we provide final 3-year follow-up data from the trial.

METHODS

This open-label, multicentre, phase 2 study (CheckMate 204) included adults (aged ≥18 years) with measurable MBM (0·5-3·0 cm in diameter). Asymptomatic patients (cohort A) had an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 and no neurological symptoms or baseline corticosteroid use; symptomatic patients (cohort B) had an ECOG performance status of 0-2 with stable neurological symptoms and could be receiving low-dose dexamethasone. Nivolumab 1 mg/kg plus ipilimumab 3 mg/kg was given intravenously every 3 weeks for four doses, followed by nivolumab 3 mg/kg every 2 weeks for up to 2 years, until disease progression or unacceptable toxicity. The primary endpoint was intracranial clinical benefit rate (complete responses, partial responses, or stable disease lasting ≥6 months) assessed in all treated patients. Intracranial progression-free survival and overall survival were key secondary endpoints. This study is registered with ClinicalTrials.gov, NCT02320058.

FINDINGS

Between Feb 19, 2015, and Nov 1, 2017, 119 (72%) of 165 screened patients were enrolled and treated: 101 patients were asymptomatic (cohort A; median follow-up 34·3 months [IQR 14·7-36·4]) and 18 were symptomatic (cohort B; median follow-up 7·5 months [1·2-35·2]). Investigator-assessed intracranial clinical benefit was observed in 58 (57·4% [95% CI 47·2-67·2]) of 101 patients in cohort A and three (16·7% [3·6-41·4]) of 18 patients in cohort B; investigator-assessed objective response was observed in 54 (53·5% [43·3-63·5]) patients in cohort A and three (16·7% [3·6-41·4]) patients in cohort B. 33 (33%) patients in cohort A and three (17%) patients in cohort B had an investigator-assessed intracranial complete response. For patients in cohort A, 36-month intracranial progression-free survival was 54·1% (95% CI 42·7-64·1) and overall survival was 71·9% (61·8-79·8). For patients in cohort B, 36-month intracranial progression-free survival was 18·9% (95% CI 4·6-40·5) and overall survival was 36·6% (14·0-59·8). The most common grade 3-4 treatment-related adverse events (TRAEs) were increased alanine aminotransferase and aspartate aminotransferase (15 [15%] of 101 patients each) in cohort A; no grade 3 TRAEs occurred in more than one patient each in cohort B, and no grade 4 events occurred. The most common serious TRAEs were colitis, diarrhoea, hypophysitis, and increased alanine aminotransferase (five [5%] of each among the 101 patients in cohort A); no serious TRAE occurred in more than one patient each in cohort B. There was one treatment-related death (myocarditis in cohort A).

INTERPRETATION

The durable 3-year response, overall survival, and progression-free survival rates for asymptomatic patients support first-line use of nivolumab plus ipilimumab. Symptomatic disease in patients with MBM remains difficult to treat, but some patients achieve a long-term response with the combination.

FUNDING

Bristol Myers Squibb.

Management of Immune-Related Adverse Events in Patients Treated With Immune Checkpoint Inhibitor Therapy: ASCO Guideline Update

PURPOSE

To increase awareness, outline strategies, and offer guidance on the recommended management of immune-related adverse events (irAEs) in patients treated with immune checkpoint inhibitor (ICPi) therapy.

METHODS

A multidisciplinary panel of medical oncology, dermatology, gastroenterology, rheumatology, pulmonology, endocrinology, neurology, hematology, emergency medicine, nursing, trialists, and advocacy experts was convened to update the guideline. Guideline development involved a systematic literature review and an informal consensus process. The systematic review focused on evidence published from 2017 through 2021.

RESULTS

A total of 175 studies met the eligibility criteria of the systematic review and were pertinent to the development of the recommendations. Because of the paucity of high-quality evidence, recommendations are based on expert consensus.

RECOMMENDATIONS

Recommendations for specific organ system-based toxicity diagnosis and management are presented. While management varies according to the organ system affected, in general, ICPi therapy should be continued with close monitoring for grade 1 toxicities, except for some neurologic, hematologic, and cardiac toxicities. ICPi therapy may be suspended for most grade 2 toxicities, with consideration of resuming when symptoms revert ≤ grade 1. Corticosteroids may be administered. Grade 3 toxicities generally warrant suspension of ICPis and the initiation of high-dose corticosteroids. Corticosteroids should be tapered over the course of at least 4-6 weeks. Some refractory cases may require other immunosuppressive therapy. In general, permanent discontinuation of ICPis is recommended with grade 4 toxicities, except for endocrinopathies that have been controlled by hormone replacement. Additional information is available at www.asco.org/supportive-care-guidelines.

Management of Immune-Related Adverse Events in Patients Treated With Chimeric Antigen Receptor T-Cell Therapy: ASCO Guideline

PURPOSE

To increase awareness, outline strategies, and offer guidance on the recommended management of immune-related adverse events (irAEs) in patients treated with chimeric antigen receptor (CAR) T-cell therapy.

METHODS

A multidisciplinary panel of medical oncology, neurology, hematology, emergency medicine, nursing, trialists, and advocacy experts was convened to develop the guideline. Guideline development involved a systematic literature review and an informal consensus process. The systematic review focused on evidence published from 2017 to 2021.

RESULTS

The systematic review identified 35 eligible publications. Because of the paucity of high-quality evidence, recommendations are based on expert consensus.

RECOMMENDATIONS

The multidisciplinary team issued recommendations to aid in the recognition, workup, evaluation, and management of the most common CAR T-cell-related toxicities, including cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome, B-cell aplasia, cytopenias, and infections. Management of short-term toxicities associated with CAR T cells begins with supportive care for most patients, but may require pharmacologic interventions for those without adequate response. Management of patients with prolonged or severe CAR T-cell-associated cytokine release syndrome includes treatment with tocilizumab with or without a corticosteroid. On the basis of the potential for rapid decline, patients with moderate to severe immune effector cell-associated neurotoxicity syndrome should be managed with corticosteroids and supportive care.Additional information is available at www.asco.org/supportive-care-guidelines.

Systemic coagulation is activated in patients with meningioma and glioblastoma

PURPOSE

Up to 30% of patients with glioblastoma (GBM) develop venous thromboembolism (VTE) over the course of the disease. Although not as high, the risk for VTE is also increased in patients with meningioma. Direct measurement of peak thrombin generation (TG) allows quantitative assessment of systemic coagulation activation in patients with GBM and meningioma. Our aim was to determine the extent of systemic coagulation activation induced by brain tumors, to measure the shift between pre- and post-operative peak TG in patients with GBM, and to assess the relationship between pre-surgical peak TG and pre-operative brain tumor volume on imaging.

METHODS

Pre- and post-surgical plasma samples were obtained from successive patients with GBM and once from patients with meningioma and healthy age- and sex-matched blood donor controls. TG was measured using the calibrated automated thrombogram (CAT) assay, and tumor volumes were measured in pre-surgical MRI scans.

RESULTS

Pre-surgical peak TG was higher in patients with GBM than in controls (288.6 ± 54.1 nM vs 187.1 ± 41.7 nM, respectively, P < 0.001), and, in the nine patients with GBM and paired data available, peak TG was significantly reduced after surgery (323 ± 38 nM vs 265 ± 52 nM, respectively, P = 0.007). Similarly, subjects with meningioma demonstrated higher peak TG compared to controls (242.2 ± 54.9 nM vs 177.7 ± 57.0 nM, respectively, P < 0.001). There was no association between peak TG and pre-operative tumor volume or overall survival.

CONCLUSION

Our results indicate that systemic coagulation activation occurs with both meningioma and GBM, but to a greater degree in the latter. Preoperative peak TG did not correlate with tumor volume, but removal of GBM caused a significant decrease in coagulation activation.

Challenges and next steps in the advancement of immunotherapy: summary of the 2018 and 2020 National Cancer Institute workshops on cell-based immunotherapy for solid tumors

Cell-based immunotherapies have had remarkable success in the clinic, specifically in the treatment of hematologic malignancies. However, these strategies have had limited efficacy in patients with solid tumors. To better understand the challenges involved, the National Cancer Institute (NCI) convened an initial workshop with immuno-oncology thought leaders in December 2018 and a follow-up workshop in December 2020. The goals of the NCI workshops on cell-based immunotherapy for solid tumors were to discuss the current state of the field of cell-based immunotherapy, obtain insights into critical knowledge gaps, and identify ways in which NCI could facilitate progress. At both meetings, subjects emphasized four main types of challenges in further developing cell-based immunotherapy for patients with solid tumors: scientific, technical, clinical, and regulatory. The scientific barriers include selecting appropriate targets, ensuring adequate trafficking of cell therapy products to tumor sites, overcoming the immunosuppressive tumor microenvironment, and identifying appropriate models for these investigations. While mouse models may provide some useful data, the majority of those that are commonly used are immunodeficient and unable to fully recapitulate the immune response in patients. There is therefore a need for enhanced support of small early-phase human clinical studies, preferably with adaptive trial designs, to provide proof of concept for novel cell therapy approaches. Furthermore, the requirements for manufacturing, shipping, and distributing cell-based therapies present technical challenges and regulatory questions, which many research institutions are not equipped to address. Overall, workshop subjects identified key areas where NCI support might help the research community in driving forward innovation and clinical utility: 1) provide focused research support on topics such as tumor target selection, immune cell fitness and persistence, cell trafficking, and the immunosuppressive tumor microenvironment; 2) support the rapid translation of preclinical findings into proof of concept clinical testing, harmonize clinical trial regimens, and facilitate early trial data sharing (including negative results); 3) expand manufacturing support for cell therapies, including vectors and reagents, and provide training programs for technical staff; and 4) develop and share standard operating procedures for cell handling and analytical assays, and work with the Food and Drug Administration to harmonize product characterization specifications.

Perspectives in Melanoma: meeting report from the Melanoma Bridge (December 3rd-5th, 2020, Italy)

Advances in immune checkpoint therapy and targeted therapy have led to improvement in overall survival for patients with advanced melanoma. Single agent checkpoint PD-1 blockade and combination with BRAF/MEK targeted therapy demonstrated benefit in overall survival (OS). Superior response rates have been demonstrated with combined PD-1/CTLA-4 blockade, with a significant OS benefit compared with single-agent PD-1 blockade. Despite the progress in diagnosis of melanocytic lesions, correct classification of patients, selection of appropriate adjuvant and systemic therapies, and prediction of response to therapy remain real challenges in melanoma. Improved understanding of the tumor microenvironment, tumor immunity and response to therapy has prompted extensive translational and clinical research in melanoma. Development of novel biomarker platforms may help to improve diagnostics and predictive accuracy for selection of patients for specific treatment. There is a growing evidence that genomic and immune features of pre-treatment tumor biopsies may correlate with response in patients with melanoma and other cancers but they have yet to be fully characterized and implemented clinically. Overall, the progress in melanoma therapeutics and translational research will help to optimize treatment regimens to overcome resistance and develop robust biomarkers to guide clinical decision-making. During the Melanoma Bridge meeting (December 3rd-5th, 2020, Italy) we reviewed the currently approved systemic and local therapies for advanced melanoma and discussed novel biomarker strategies and advances in precision medicine.

Clinical characteristics, time course, treatment and outcomes of patients with immune checkpoint inhibitor-associated myocarditis

Background

Immune checkpoint inhibitors (ICI) have emerged as a front-line therapy for a variety of solid tumors. With the widespread use of these agents, immune-associated toxicities are increasingly being recognized, including fatal myocarditis. There are limited data on the outcomes and prognostic utility of biomarkers associated with ICI-associated myocarditis. Our objective was to examine the associations between clinical biomarkers of cardiomyocyte damage and mortality in patients with cancer treated with ICIs.

Methods

We retrospectively studied 23 patients who developed symptomatic and asymptomatic troponin elevations while receiving ICI therapy at a National Cancer Institute-designated comprehensive cancer center. We obtained serial ECGs, troponin I, and creatine kinase-MD (CK-MB), in addition to other conventional clinical biomarkers, and compared covariates between survivors and non-survivors.

Results

Among patients with myocarditis, higher troponin I (p=0.037) and CK-MB (p=0.034) levels on presentation correlated with progression to severe myocarditis. Higher troponin I (p=0.016), CK (p=0.013), and CK-MB (p=0.034) levels were associated with increased mortality, while the presence of advanced atrioventricular block on presentation (p=0.088) trended toward increased mortality. Weekly troponin monitoring lead to earlier hospitalization for potential myocarditis (p=0.022) and was associated with decreased time to steroid initiation (p=0.053) and improved outcomes.

Conclusions

Routine troponin surveillance may be helpful in predicting mortality in ICI-treated patients with cancer in the early phase of ICI therapy initiation. Early detection of troponin elevation is associated with earlier intervention and improved outcomes in ICI-associated myocarditis. The recommended assessment and diagnostic studies guiding treatment decisions are presented.

NCCN Guidelines Insights: Management of Immunotherapy-Related Toxicities, Version 1.2020

The NCCN Guidelines for Management of Immunotherapy-Related Toxicities provide interdisciplinary guidance on the management of immune-related adverse events (irAEs) resulting from cancer immunotherapy. These NCCN Guidelines Insights describe symptoms that may be caused by an irAE and should trigger further investigation, and summarize the NCCN Management of Immunotherapy-Related Toxicities Panel discussions for the 2020 update to the guidelines regarding immune checkpoint inhibitor-related diarrhea/colitis and cardiovascular irAEs.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immune checkpoint inhibitor-related adverse events

Immune checkpoint inhibitors (ICIs) are the standard of care for the treatment of several cancers. While these immunotherapies have improved patient outcomes in many clinical settings, they bring accompanying risks of toxicity, specifically immune-related adverse events (irAEs). There is a need for clear, effective guidelines for the management of irAEs during ICI treatment, motivating the Society for Immunotherapy of Cancer (SITC) to convene an expert panel to develop a clinical practice guideline. The panel discussed the recognition and management of single and combination ICI irAEs and ultimately developed evidence- and consensus-based recommendations to assist medical professionals in clinical decision-making and to improve outcomes for patients.

Using the tumor microenvironment to identify predictors of immunotoxicity to checkpoint inhibitors

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Background: While Immune checkpoint inhibitors (ICI) have revolutionized the field of oncology, the benefits have come at the cost of serious side effects known as immune-related adverse events (irAEs). Approaches that can predict patients’ susceptibility to irAEs are key to their early detection and management. In the present study, we investigate the association between irAEs reported during ICI therapy across multiple cancer types and markers of tumor immune response. Our primary objective is to explore potential biomarkers for assessing patients’ risk of irAEs. Methods: 472 patients were evaluated who had tumor immune profiling performed paraffin embedded formalin fixed archival tumor biopsy samples using Omniseq Immune Report Card (IRC) and subsequently underwent ICI therapy. The IRC consisted of enumeration of tumor infiltrating lymphocytes (TILs) by immunohistochemistry (IHC) and TIL-associated genes by RNA-Seq, PD-L1 expression by IHC, and tumor mutational burden (TMB) by DNA-Seq. irAE type and grade were determined based on retrospective chart review. Fisher’s exact test was used to determined statistically significant associations between immune markers and irAE development. Results: Patients with lung (55%), ovarian (9%), and melanoma (5%) cancers constituted the majority of the cases. The median age of patients was 61, with 56% being female and 44% male. Most patients underwent treatment with (94%). irAEs developed in 36% of patients, with 2% of patients developing high-grade irAEs (Grade 3 or 4). Skin (11%), thyroid (10%), and GI (9%), were the most commonly affected organ systems. Increased TILs were associated with increased risk for any irAE (p = 0.04). A stronger association was noted in patients who underwent anti-PD-1/L1 monotherapy (p = 0.01) and/or in cases of lung cancer (p = 0.01). Interestingly, subanalyses by gender showed a statistically significant correlation between increased TILs and risk for any irAE in males (p = 0.006) but not in females (p = 0.63). High PD-L1 (defined as > 70% by IHC) was also significantly associated with increased risk for any irAE (p = 0.03). Subanalyses by gender and age again showed a similar association in females (p = 0.0002) and/or patients < 65 years (p = 0.04). high TMB and any irAE in female patients (p = 0.01) and in breast cancer cases (p = 0.03). On multivariate analysis, TILs by IHC appeared to be the strongest predictor of irAEs (p = 0.03). Conclusions: The tumor immune microenvironment (TME) has been shown to influence response to ICI, yet its association with irAEs has not been well studied. Our analysis sheds light on potential TME predictors for irAE in patients receiving ICI therapy. Further studies are needed to deepen our understanding of immune toxicity and to develop tools for identifying patients who are at risk.

ARTISTRY-1: Nemvaleukin alfa monotherapy and in combination with pembrolizumab in patients (pts) with advanced solid tumors

2513

Background: Nemvaleukin alfa (nemvaleukin, ALKS 4230) is a novel, engineered cytokine that selectively binds the intermediate-affinity interleukin-2 (IL-2) receptor complex to preferentially activate CD8+ T cells and natural killer cells with minimal expansion of regulatory T cells, designed to leverage antitumor effects of the IL-2 pathwaywhile mitigating potential toxicity that would limit use. Methods: ARTISTRY-1 (NCT02799095) is a phase 1/2 study. Parts A (dose escalation 0.1-10 µg/kg) and B (6 µg/kg [recommended phase 2 dose]) are monotherapy; pts receive intravenous nemvaleukin for 5 days every 14 or 21 days. In Part C, pts receive nemvaleukin (3 or 6 µg/kg) every 21 days in combination with pembrolizumab (200 mg on day 1). We present safety and antitumor activity (RECIST v1.1, iRECIST) data as of 12/02/2020. Results: In Part A, 39 pts received nemvaleukin. No dose-limiting toxicities were observed; maximum tolerated dose was not reached. Part B enrolled immune checkpoint inhibitor–pretreated pts into melanoma or renal cell carcinoma (RCC) cohorts. 18 pts with melanoma enrolled; 10 were evaluable, 2 (both with metastatic mucosal melanoma) achieved a partial response (PR; 1 unconfirmed). 24 pts with RCC enrolled; 1 of 16 evaluable pts achieved a PR (awaiting confirmation). 12 pts in each cohort continue on study. In Parts A and B, treatment-related adverse events in ≥40% included chills (74.4% and 52.4%, respectively) and pyrexia (74.4% and 47.6%, respectively). In Part C (83 evaluable pts), 12 objective responses (OR) were observed; an additional 5 pts had stable disease (SD) >6 months (1 pt with breast cancer, 2 with ovarian cancer, and 2 with non-small-cell lung cancer). Nemvaleukin did not demonstrate any additive toxicity to that already established with pembrolizumab alone. OR data are summarized in the table. Conclusions: Nemvaleukin was generally well tolerated and demonstrated antitumor activity as monotherapy and in combination with pembrolizumab. Pharmacodynamic studies to identify biomarkers are ongoing. Future research of monotherapy and combination therapy with nemvaleukin is warranted. Clinical trial information: NCT02799095. [Table: see text]

Selection of the recommended phase 2 dose (RP2D) for subcutaneous nemvaleukin alfa: ARTISTRY-2

2552

Background: Nemvaleukin alfa (nemvaleukin, ALKS 4230) is a novel engineered cytokine that selectively binds the intermediate-affinity interleukin-2 receptor to preferentially activate CD8+ T and natural killer (NK) cells with minimal expansion of regulatory T cells (Tregs),designed for use as a cancer immunotherapy. ARTISTRY-2 (NCT03861793) is an ongoing phase 1/2 study evaluating the safety, efficacy, and pharmacokinetic and pharmacodynamic (PD) responses of subcutaneous (SC) nemvaleukin in combination with pembrolizumab in patients (pts) with advanced solid tumors. Methods: In phase 1, cohort-specific doses of SC nemvaleukin are administered on an every-7-day (q7d) or every-21-day (q21d) schedule during a 6-week monotherapy lead-in period, followed by combination with pembrolizumab 200 mg q21d. We present safety, PD effects, and preliminary clinical activity outcomes as of 12/02/2020. Results: 57 pts received nemvaleukin doses ranging from 0.3 mg to 6 mg q7d or 1 mg to 10 mg q21d. The most frequent tumor types (> 5 pts) were colorectal, pancreatic, ovarian, and lung; median number of prior therapies was 4. Treatment-related adverse events (TRAEs) in > 30% pts overall were pyrexia (43.9%), chills (38.6%), injection site erythema (33.3%), injection site reaction (33.3%), and fatigue (31.6%). 3 mg q7d (n = 7) had no drug-related dose reductions, discontinuations, or deaths during the monotherapy or combination periods. 6 mg was declared the maximum tolerated dose (MTD) for q7d dosing as 2 of 8 pts experienced dose-limiting toxicities (DLTs). For 6 mg q21d (n = 7), no drug-related dose reductions, discontinuations, or deaths have occurred during the monotherapy period; combination period data are not mature. 10 mg was declared the MTD for q21d dosing as 1 of 9 pts experienced DLTs and 3 had TRAEs leading to dose reductions. Systemic exposure to nemvaleukin increased with increasing dose. Increases in NK cells and CD8+ T cells of approximately 16-fold and 3-fold, respectively, at 3 mg q7d, and approximately 8-fold and 3-fold, respectively, at 6 mg q21d were observed, with minimal change in Tregs. 46 pts had at least 1 on-treatment scan as of the data cutoff date, and 30 (65%) had stable disease (SD) on the first scan. Of the 30 pts with ≥2 scans, 13 (43%) had 2+ consecutive scans of SD. 16 of 57 pts remain on therapy. Antitumor activity data for more recent cohorts are still maturing. Based on the totality of the safety, PD effects, and antitumor activity data, 3 mg q7d was selected as the RP2D for SC nemvaleukin. Conclusions: SC nemvaleukin 3 mg q7d was generally well tolerated as monotherapy and in combination with pembrolizumab, and demonstrated robust PD effects on NK cells and CD8+ T cells with minimal expansion of Tregs. These PD effects are similar to or greater than those observed with intravenous nemvaleukin. Thus, 3 mg q7d was selected as RP2D; phase 2 expansion cohorts for combination with pembrolizumab are enrolling. Clinical trial information: NCT03861793.

Case Report: Immune Checkpoint Inhibitor-Induced Exuberant Tumor Inflammation With Accelerated Clinical Deterioration in Metastatic Renal Cell Carcinoma

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy. Nivolumab, an anti-PD-1 monoclonal antibody, markedly improved overall survival in advanced renal cell carcinoma (RCC). However, ICIs can rarely trigger massive inflammation, a phenomenon characterized by rapid acceleration in radiographic tumor growth, the mechanisms underlying which are largely unknown. We report three patients with metastatic RCC who experienced rapid radiographic progression and clinical deterioration following treatment with nivolumab. However, histological analysis revealed no viable cancer despite the evidence of radiological progression. Instead, extensive necrosis and lymphohistiocytic infiltration were noted, as described previously in patients with ICI-induced pseudoprogression. Based on these observations, we postulate that exuberant antitumor inflammatory responses may contribute to adverse clinical outcomes in some patients with ICI-induced radiographic progression. Prospective studies incorporating tumor biopsies may shed more light on this rare phenomenon.

Safety and Efficacy of the Combination of Nivolumab Plus Ipilimumab in Patients With Melanoma and Asymptomatic or Symptomatic Brain Metastases (CheckMate 204)

Background

In patients with melanoma and asymptomatic brain metastases (MBM), nivolumab plus ipilimumab provided an intracranial response rate of 55%. Here, we present the first report for patients who were symptomatic and/or required corticosteroids and updated data for asymptomatic patients.

Methods

Patients with measurable MBM, 0.5-3.0 cm, were enrolled into Cohort A (asymptomatic) or Cohort B (stable neurologic symptoms and/or receiving corticosteroids). Nivolumab, 1 mg/kg, and ipilimumab, 3 mg/kg, were given intravenously every 3 weeks ×4, followed by nivolumab, 3 mg/kg, every 2 weeks until progression, unacceptable toxicity, or 24 months. The primary endpoint was intracranial clinical benefit rate (CBR; complete response [CR], partial response [PR], or stable disease ≥6 months).

Results

Symptomatic patients (N = 18) received a median of one nivolumab and ipilimumab combination dose and had an intracranial CBR of 22.2%. Two of 12 patients on corticosteroids had CR; 2 responded among the 6 not on corticosteroids. Median intracranial progression-free survival (PFS) and overall survival (OS) were 1.2 and 8.7 months, respectively. In contrast, with 20.6 months of follow-up, we confirmed an intracranial CBR of 58.4% in asymptomatic patients (N = 101); median duration of response, PFS, and OS were not reached. No new safety signals were observed.

Conclusions

Nivolumab plus ipilimumab provides durable clinical benefit for asymptomatic patients with MBM and should be considered for first-line therapy. This regimen has limited activity in MBM patients with neurologic symptoms and/or requiring corticosteroids, supporting the need for alternative approaches and methods to reduce the dependency on corticosteroids.

Clinical trial registration. ClinicalTrials.gov, NCT02320058.

Co-Isolation of Cytokines and Exosomes: Implications for Immunomodulation Studies

Exosomes play a vital role in intercellular communication and their immunomodulatory potential have become an important focus in cancer research. Various methods have been developed for the isolation although each method differs in the number and purity of exosomes they yield. In melanoma, tumor-derived exosomes drive immunosuppression within the tumor microenvironment. The co-elution of exosomes and soluble factors such as cytokines during isolation, however, make it difficult to ascertain the contribution of exosome cargo, as soluble cytokines are equally capable of immune suppression. In this review we will expound upon the biological relevance that exosome-associated cytokines possess. Furthermore, we discuss the technical challenges that arise during exosome isolation and what this means for further studies into the TME and in vivo work.

Neoadjuvant Pembrolizumab and High-Dose IFNα-2b in Resectable Regionally Advanced Melanoma

PURPOSE

Neoadjuvant immunotherapy may improve the clinical outcome of regionally advanced operable melanoma and allows for rapid clinical and pathologic assessment of response. We examined neoadjuvant pembrolizumab and high-dose IFNα-2b (HDI) therapy in patients with resectable advanced melanoma.

PATIENTS AND METHODS

Patients with resectable stage III/IV melanoma were treated with concurrent pembrolizumab 200 mg i.v. every 3 weeks and HDI 20 MU/m²/day i.v., 5 days per week for 4 weeks, then 10 MU/m²/day subcutaneously 3 days per week for 2 weeks. Definitive surgery followed, as did adjuvant combination immunotherapy, completing a year of treatment. Primary endpoint was safety of the combination. Secondary endpoints included overall response rate (ORR), pathologic complete response (pCR), recurrence-free survival (RFS), and overall survival (OS). Blood samples for correlative studies were collected throughout. Tumor tissue was assessed by IHC and flow cytometry at baseline and at surgery.

RESULTS

A total of 31 patients were enrolled, and 30 were evaluable. At data cutoff (October 2, 2019), median follow-up for OS was 37.87 months (range, 33.2-43.47). Median OS and RFS were not reached. Radiographic ORR was 73.3% [95% confidence interval (CI): 55.5-85.8], with a 43% (95% CI: 27.3-60.1) pCR rate. None of the patients with a pCR have had a recurrence. HDI and pembrolizumab were discontinued in 73% and 43% of patients, respectively. Correlative analyses suggested that intratumoral PD-1/PD-L1 interaction and HLA-DR expression are associated with pCR (P = 0.002 and P = 0.008, respectively).

CONCLUSIONS

Neoadjuvant concurrent HDI and pembrolizumab demonstrated promising clinical activity despite high rates of treatment discontinuation. pCR is a prognostic indicator.See related commentary by Menzies et al., p. 4133.

ALKS 4230: a novel engineered IL-2 fusion protein with an improved cellular selectivity profile for cancer immunotherapy

BACKGROUND

Interleukin-2 (IL-2) plays a pivotal role in immune homeostasis due to its ability to stimulate numerous lymphocyte subsets including natural killer (NK) cells, effector CD4⁺ and CD8⁺ T cells, and regulatory T cells (T_regs). Low concentrations of IL-2 induce signaling through the high-affinity IL-2 receptor (IL-2R) comprised of IL-2Rα, IL-2Rβ, and common γ chain (γ_c), preferentially expressed on T_regs. Higher concentrations of IL-2 are necessary to induce signaling through the intermediate-affinity IL-2R, composed of IL-2Rβ and γ_c, expressed on memory CD8⁺ T cells and NK cells. Recombinant human IL-2 (rhIL-2) is approved for treatment of metastatic melanoma and renal cell carcinoma (RCC), but adverse events including capillary leak syndrome, potentially mediated through interaction with the high-affinity IL-2R, limit its therapeutic use. Furthermore, antitumor efficacy of IL-2 may also be limited by preferential expansion of immunosuppressive T_regs. ALKS 4230 is an engineered fusion protein comprised of a circularly-permuted IL-2 with the extracellular domain of IL-2Rα, designed to selectively activate effector lymphocytes bearing the intermediate-affinity IL-2R.

RESULTS

ALKS 4230 was equipotent to rhIL-2 in activating human cells bearing the intermediate-affinity IL-2R, and less potent than rhIL-2 on cells bearing the high-affinity IL-2R. As observed in vitro with primary human cells from healthy donors and advanced cancer patients, ALKS 4230 induced greater activation and expansion of NK cells with reduced expansion of T_regs relative to rhIL-2. Similarly, in mice, ALKS 4230 treatment stimulated greater expansion of NK cells and memory-phenotype CD8⁺ T cells at doses that did not expand or activate T_regs. ALKS 4230 treatment induced significantly lower levels of proinflammatory cytokines, including tumor necrosis factor alpha, interleukin-6, and interferon gamma relative to rhIL-2. Furthermore, ALKS 4230 exhibited superior antitumor efficacy in the mouse B16F10 lung tumor model, where ALKS 4230 could be administered via multiple routes of administration and dosing schedules while achieving equivalent antitumor efficacy.

CONCLUSIONS

ALKS 4230 exhibited enhanced pharmacokinetic and selective pharmacodynamic properties resulting in both improved antitumor efficacy and lower indices of toxicity relative to rhIL-2 in mice. These data highlight the potential of ALKS 4230 as a novel cancer immunotherapy, and as such, the molecule is being evaluated clinically.

T-cell CX3CR1 expression as a dynamic blood-based biomarker of response to immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) have revolutionized treatment for various cancers; however, durable response is limited to only a subset of patients. Discovery of blood-based biomarkers that reflect dynamic change of the tumor microenvironment, and predict response to ICI, will markedly improve current treatment regimens. Here, we investigate CX3C chemokine receptor 1 (CX3CR1), a marker of T-cell differentiation, as a predictive correlate of response to ICI therapy. Successful treatment of tumor-bearing mice with ICI increases the frequency and T-cell receptor clonality of the peripheral CX3CR1+CD8+ T-cell subset that includes an enriched repertoire of tumor-specific and tumor-infiltrating CD8+ T cells. Furthermore, an increase in the frequency of the CX3CR1+ subset in circulating CD8+ T cells early after initiation of anti-PD-1 therapy correlates with response and survival in patients with non-small cell lung cancer. Collectively, these data support T-cell CX3CR1 expression as a blood-based dynamic early on-treatment predictor of response to ICI therapy.

Resident and circulating memory T cells persist for years in melanoma patients with durable responses to immunotherapy

While T-cell responses to cancer immunotherapy have been avidly studied, long-lived memory has been poorly characterized. In a cohort of metastatic melanoma survivors with exceptional responses to immunotherapy, we probed memory CD8+ T-cell responses across tissues, and across several years. Single-cell RNA sequencing revealed three subsets of resident memory T (TRM) cells shared between tumors and distant vitiligo-affected skin. Paired T-cell receptor sequencing further identified clonotypes in tumors that co-existed as TRM in skin and as effector memory T (TEM) cells in blood. Clonotypes that dispersed throughout tumor, skin, and blood preferentially expressed a IFNG / TNF-high signature, which had a strong prognostic value for melanoma patients. Remarkably, clonotypes from tumors were found in patient skin and blood up to nine years later, with skin maintaining the most focused tumor-associated clonal repertoire. These studies reveal that cancer survivors can maintain durable memory as functional, broadly-distributed TRM and TEM compartments.

A Rapid Exosome Isolation Using Ultrafiltration and Size Exclusion Chromatography (REIUS) Method for Exosome Isolation from Melanoma Cell Lines

Cells release extracellular vesicles (EVs) that can be detected both in vivo and in cell culture medium. Among EVs, exosomes are 50-150 nm vesicles that are systematically packaged into multivesicular bodies for release into the external environment. In cancer, these intentionally packaged exosomes carry a payload of proteins such as RNAs and surface receptors that facilitate the reprogramming of proximal cells to assemble a protumor microenvironment. Exosomes have been implicated as an important intermediary extracellular communication pathway between cells, including in melanoma. Human melanoma-derived exosomes (HMEX) have been demonstrated to modulate the extracellular environment and inhibit immune cell activation. There are many methods to isolate and enrich for exosomes and the method applied can impact yield and purity of the isolates. In this chapter we describe the REIUS (rapid exosome isolation using ultrafiltration and size exclusion chromatography) method to isolate HMEX from melanoma cell cultures and then demonstrate their enrichment using molecular and microscopic approaches.

Systemic Therapy for Melanoma: ASCO Guideline

PURPOSE

To provide guidance to clinicians regarding the use of systemic therapy for melanoma.

METHODS

ASCO convened an Expert Panel and conducted a systematic review of the literature.

RESULTS

A systematic review, one meta-analysis, and 34 additional randomized trials were identified. The published studies included a wide range of systemic therapies in cutaneous and noncutaneous melanoma.

RECOMMENDATIONS

In the adjuvant setting, nivolumab or pembrolizumab should be offered to patients with resected stage IIIA/B/C/D BRAF wild-type cutaneous melanoma, while either of those two agents or the combination of dabrafenib and trametinib should be offered in BRAF-mutant disease. No recommendation could be made for or against the use of neoadjuvant therapy in cutaneous melanoma. In the unresectable/metastatic setting, ipilimumab plus nivolumab, nivolumab alone, or pembrolizumab alone should be offered to patients with BRAF wild-type cutaneous melanoma, while those three regimens or combination BRAF/MEK inhibitor therapy with dabrafenib/trametinib, encorafenib/binimetinib, or vemurafenib/cobimetinib should be offered in BRAF-mutant disease. Patients with mucosal melanoma may be offered the same therapies recommended for cutaneous melanoma. No recommendation could be made for or against specific therapy for uveal melanoma. Additional information is available at www.asco.org/melanoma-guidelines.

Phase I Clinical Trial of Combination Propranolol and Pembrolizumab in Locally Advanced and Metastatic Melanoma: Safety, Tolerability, and Preliminary Evidence of Antitumor Activity

PURPOSE

Increased β-adrenergic receptor (β-AR) signaling has been shown to promote the creation of an immunosuppressive tumor microenvironment (TME). Preclinical studies have shown that abrogation of this signaling pathway, particularly β2-AR, provides a more favorable TME that enhances the activity of anti-PD-1 checkpoint inhibitors. We hypothesize that blocking stress-related immunosuppressive pathways would improve tumor response to immune checkpoint inhibitors in patients. Here, we report the results of dose escalation of a nonselective β-blocker (propranolol) with pembrolizumab in patients with metastatic melanoma.

PATIENTS AND METHODS

A 3 + 3 dose escalation study for propranolol twice a day with pembrolizumab (200 mg every 3 weeks) was completed. The primary objective was to determine the recommended phase II dose (RP2D). Additional objectives included safety, antitumor activity, and biomarker analyses. Responders were defined as patients with complete or partial response per immune-modified RECIST at 6 months.

RESULTS

Nine patients with metastatic melanoma received increasing doses of propranolol in cohorts of 10, 20, and 30 mg twice a day. No dose-limiting toxicities were observed. Most common treatment-related adverse events (TRAEs) were rash, fatigue, and vitiligo, observed in 44% patients. One patient developed two grade ≥3 TRAEs. Objective response rate was 78%. While no significant changes in treatment-associated biomarkers were observed, an increase in IFNγ and a decrease in IL6 was noted in responders.

CONCLUSIONS

Combination of propranolol with pembrolizumab in treatment-naïve metastatic melanoma is safe and shows very promising activity. Propranolol 30 mg twice a day was selected as RP2D in addition to pembrolizumab based on safety, tolerability, and preliminary antitumor activity.

Mechanism-based treatment of cancer with immune checkpoint inhibitor therapies

Immune checkpoints are cell surface molecules that initiate regulatory pathways which have powerful control of CD8+ cytolytic T cell activity. Antagonistic and agonistic antibodies engaging these molecules have demonstrated profound impact on immune activation and have entered clinical use for the treatment of a variety of diseases. Over the past decade, antagonistic antibodies known as immune checkpoint inhibitors have become a new pillar of cancer treatment and have reshaped the therapeutic landscape in oncology. These agents differ in their mechanism of action and toxicity profiles compared to more traditional systemic cancer treatments such as chemo- and targeted therapies. This article reviews the pharmacology of this new class of agents.

An Immunosuppressive Effect of Melanoma-derived Exosomes on NY-ESO-1 Antigen-specific Human CD8+ T Cells is Dependent on IL-10 and Independent of BRAFV600E Mutation in Melanoma Cell Lines

Exosomes, including human melanoma-derived exosomes (HMEX), are known to suppress the function of immune effector cells, which for HMEX has been associated with the surface presence of the immune checkpoint ligand PD-L1. This study investigated the relationship between the BRAF mutational status of melanoma cells and the inhibition of secreted HMEX exosomes on antigen-specific human T cells. Exosomes were isolated from two melanoma cell lines, 2183-Her4 and 888-mel, which are genetically wild-type BRAF^WT and BRAF^V600E, respectively. HMEX were isolated using a modified, size-exclusion chromatography (SEC) method shown to reduce co-isolation of non-exosome-associated cytokines compared to ultracentrifugation isolation. The immunoinhibitory effect of the exosomes was tested in vitro on patient-derived NY-ESO-1-specific CD8⁺ T cells challenged with NY-ESO-1 antigen. HMEX from both cell lines inhibited the immune response of antigen-specific T cells comparably, as evidenced by the reduction of IFN-γ and TNF-α in NY-ESO-1 tetramer-positive cells. This inhibition could be partially reversed by the presence of anti-PD-L1 and anti-IL-10 antibodies. IL-10 has been demonstrated to be a critical pathway for sustaining enhanced tumorigenesis in BRAF^V600E mutant cells compared to BRAF^WT melanoma cells. Thus, we demonstrate that HMEX inhibit antigen-specific T cell responses independent of the BRAF mutational status of the parent cells. In addition, PD-L1 and IL-10 contribute to the HMEX-mediated immunosuppression of antigen-specific human T cells. The inhibitory capacity of exosomes should be taken into consideration when developing therapies that are reliant upon the potency of customized, antigen-specific effector T cells.

Human genes differ by their UV sensitivity estimated through analysis of UV-induced silent mutations in melanoma

We hypothesized that human genes differ by their sensitivity to ultraviolet (UV) exposure. We used somatic mutations detected by genome-wide screens in melanoma and reported in the Catalog Of Somatic Mutations In Cancer. As a measure of UV sensitivity, we used the number of silent mutations generated by C>T transitions in pyrimidine dimers of a given transcript divided by the number of potential sites for this type of mutations in the transcript. We found that human genes varied by UV sensitivity by two orders of magnitude. We noted that the melanoma-associated tumor suppressor gene CDKN2A was among the top five most UV-sensitive genes in the human genome. Melanoma driver genes have a higher UV-sensitivity compared with other genes in the human genome. The difference was more prominent for tumor suppressors compared with oncogene. The results of this study suggest that differential sensitivity of human transcripts to UV light may explain melanoma specificity of some driver genes. Practical significance of the study relates to the fact that differences in UV sensitivity among human genes need to be taken into consideration whereas predicting melanoma-associated genes by the number of somatic mutations detected in a given gene.

Abstract A82: Immune checkpoint protein VISTA controls antitumor immunity via regulating Toll-like receptor signaling and myeloid cells-mediated inflammation

Introduction: V-domain Ig suppressor of T-cell activation (VISTA, gene Vsir) is an inhibitory immune-checkpoint molecule that suppresses CD4+ and CD8+ T-cell activation. Vsir-/- mice developed chronic inflammatory phenotypes, and Vsir-/- CD4+ and CD8+ T cells were hyper-responsive towards self- and foreign antigens. Our recent study (Li et al., Sci Rep 2017) has identified a novel role of VISTA as a critical regulator of IL-23/IL-17 inflammatory axis induced by Toll-like receptor (TLR) stimulation. The molecular mechanisms by which VISTA inhibits TLR signaling remain to be elucidated.

Methods: Peritoneal macrophages from WT or Vsir-/- mice were isolated and stimulated with TLR agonists. Alternatively, human monocyte THP-1 cells overexpressing VISTA were stimulated by TLR2 agonist Pam3CSK4. The activation of TLR signaling pathways and the production of inflammatory cytokines were examined by Western blotting, gel shift assay, or ELISA. Tumor-bearing mice were treated with VISTA-specific monoclonal antibody (mAb) and a peptide vaccine containing TLR agonists. The production of inflammatory cytokines and chemokines was examined via RT-PCR and ELISA.

Results: VISTA downregulates Toll-like receptor (TLR)/TRAF6/TAK1-mediated signaling pathway via promoting K48-linked polyubiquitination and proteasomal degradation of TRAF6 and inhibiting K63-linked polyubiquitination and activation of TRAF6. VISTA blockade by an antibody or genetic deletion augments the activation of MAPKs/AP-1 and IKK/NF-kB signaling cascades in myeloid cells and induces the accumulation of inflammatory cytokines and chemokines within tumor tissues. Inflamed tumor tissues promote the infiltration and effector function of tumor-reactive CD8+ T cells. TLR/TRAF6-mediated inflammatory responses promote the antitumor efficacy of VISTA-blocking antibodies and contribute to a synergistic outcome when VISTA blockade is combined with a TLR agonistic vaccine.

Conclusions: Our study establishes that VISTA critically regulates the inflammatory responses of myeloid cells mediated by TLR signaling. Unlike targeting other immune checkpoint proteins, the therapeutic efficacy of VISTA inhibition benefits from the activation of myeloid cells and early induction of inflammatory cytokines may predict positive clinical responses.

Citation Format: Wenwen Xu, Yongwei Zheng, Juan Zhou, Ying Yuan, Hieu Minh Ta, Jun Dong, Halli E. Miller, Michael Olson, Kamalakannan Rajasekaran, Marc S. Ernstoff, Demin Wang, Subramaniam Malarkannan, Li Wang. Immune checkpoint protein VISTA controls antitumor immunity via regulating Toll-like receptor signaling and myeloid cells-mediated inflammation [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A82.

Autoimmune diseases and immune-checkpoint inhibitors for cancer therapy: review of the literature and personalized risk-based prevention strategy

Patients with cancer and with preexisting active autoimmune diseases (ADs) have been excluded from immunotherapy clinical trials because of concerns for high susceptibility to the development of severe adverse events resulting from exacerbation of their preexisting ADs. However, a growing body of evidence indicates that immune-checkpoint inhibitors (ICIs) may be safe and effective in this patient population. However, baseline corticosteroids and other nonselective immunosuppressants appear to negatively impact drug efficacy, whereas retrospective and case report data suggest that use of specific immunosuppressants may not have the same consequences. Therefore, we propose here a two-step strategy. First, to lower the risk of compromising ICI efficacy before their initiation, nonselective immunosuppressants could be replaced by specific selective immunosuppressant drugs following a short rotation phase. Subsequently, combining ICI with the selective immunosuppressant could prevent exacerbation of the AD. For the most common active ADs encountered in the context of cancer, we propose specific algorithms to optimize ICI therapy. These preventive strategies go beyond current practices and recommendations, and should be practiced in ICI-specialized clinics, as these require multidisciplinary teams with extensive knowledge in the field of clinical immunology and oncology. In addition, we challenge the exclusion from ICI therapy for patients with cancer and active ADs and propose the implementation of an international registry to study such novel strategies in a prospective fashion.

Impact of concomitant medication use and immune-related adverse events on response to immune checkpoint inhibitors

Aim: Patients receiving checkpoint inhibitors (CPI) are frequently on other medications for co-morbidities. We explored the impact of concomitant medication use on outcomes. Materials & methods: 210 metastatic cancer patients on CPI were identified and association between concomitant medication use and immune-related adverse events with clinical outcomes was determined. Results: Aspirin, metformin, β-blockers and statins were not shown to have any statistically significant difference on clinical benefit. 26.3% patients with clinical benefit developed rash versus 11.8% without clinical benefit (p < 0.05) on multivariate analysis. Conclusion: Use of common prescription and nonprescription medications in patients with multiple co-morbidities appears safe and does not have an adverse effect on CPI efficacy. The presence of rash predicted for a better response.

Purity and yield of melanoma exosomes are dependent on isolation method

Both exosomes and soluble factors have been implicated in the generation of an immunosuppressive tumour microenvironment. Determining the contribution of each requires stringent control of purity of the isolated analytes. The present study compares several conventional exosome isolation methods for the presence of co-enriched soluble factors while isolating exosomes from human melanoma-derived cell lines. The resultant preparations were analysed by multiplex bead array analysis for cytokine profiles, and by electron microscopy and nanotracking analysis for exosome size distribution and concentration. It is demonstrated that the amount and repertoire of soluble factors in exosome preparations is dependent upon the isolation method used. A combination of ultrafiltration and size exclusion chromatography yielded up to 58-fold more exosomes than ultracentrifugation, up to 836-fold lower concentrations of co-purified soluble factors when adjusted for exosome yield, and a greater than two-fold increase in PD-L1 expressing exosomes. Mechanistically, in context of the immunomodulatory effects of exosomes, the exosome isolation method should be carefully considered in order to limit any effects due instead to co-eluted soluble factors.

Combination of pembrolizumab and imatinib in a patient with double KIT mutant melanoma: A case report

RATIONALE

The treatment of metastatic melanoma has been revolutionized in the past decade because of the development of immunotherapies and targeted therapies. Despite these developments, there is still an unmet clinical need for more advanced combination therapies for the subset of patients who remain resistant to immunotherapy or targeted therapy alone. To our knowledge, no reports have been published on combinations of PD-1 blockades and c-KIT inhibitors in melanoma patients. Furthermore, data are limited regarding the safety and efficacy of this combination in patients harboring KIT mutations.

PATIENT CONCERNS AND DIAGNOSIS

We report a case of an 82-year-old female with metastatic melanoma who was found to have double KIT mutations at V559 and N822I.

INTERVENTIONS

She was treated with a combination of c-KIT inhibitor and PD-1 blockade after being resistant to anti-PD-1 monotherapy.

OUTCOMES

Patient developed two episodes of grade 2 liver toxicity requiring treatment breaks followed by a dose reduction. Her transaminitis eventually resolved and patient remained on combination treatment for almost two years with good control of her disease prior to progression.

LESSONS

Treatment options for patients who progress after PD-1 inhibitors are very limited; therefore, there is a high unmet clinical need for this patient population. Combining Imatinib with checkpoint inhibitors may be efficacious in patients with metastatic melanoma and KIT mutations. This novel combination can cause additional toxicities which seem to be overall manageable.

Immunological Correlates of Response to Immune Checkpoint Inhibitors in Metastatic Urothelial Carcinoma

BACKGROUND

The identification of prognostic and/or predictive biomarkers for response to immune checkpoint inhibitors (ICI) could help guide treatment decisions.

OBJECTIVE

We assessed changes in programmed cell death-1 (PD1)/PD1 ligand (PDL1) expression in key immunomodulatory cell subsets (myeloid-derived suppressor cells [MDSC]; cytotoxic T lymphocytes [CTL]) following ICI therapy and investigated whether these changes correlated with outcomes in patients with metastatic urothelial carcinoma (mUC).

PATIENTS AND METHODS

Serial peripheral blood samples were collected from ICI-treated mUC patients. Flow cytometry was used to quantify PD1/PDL1 expression on MDSC (CD33⁺HLADR^-) and CTL (CD8⁺CD4^-) from peripheral blood mononuclear cells. MDSC were grouped into monocytic (M)-MDSC (CD14⁺CD15^-), polymorphonuclear (PMN)-MDSC (CD14^-CD15⁺), and immature (I)-MDSC (CD14^-CD15^-). Mixed-model regression and Wilcoxon signed-rank or rank-sum tests were performed to assess post-ICI changes in immune biomarker expression and identify correlations between PD1/PDL1 expression and objective response to ICI.

RESULTS

Of 41 ICI-treated patients, 26 received anti-PDL1 (23 atezolizumab/3 avelumab) and 15 received anti-PD1 (pembrolizumab) therapy. Based on available data, 27.5% had prior intravesical Bacillus Calmette-Guérin therapy, 42% had prior neoadjuvant chemotherapy, and 70% had prior cystectomy or nephroureterectomy. Successive doses of anti-PDL1 correlated with decreased percentage of PDL1⁺ (%PDL1⁺) M-MDSC, while doses of anti-PD1 correlated with decreased %PD1⁺ M- and I-MDSC. Although pre-treatment %PD1⁺ CTL did not predict response, a greater %PD1⁺ CTL within 9 weeks after ICI initiation correlated with objective response.

CONCLUSIONS

Treatment with ICI correlated with distinct changes in PD1/PDL1-expressing peripheral immune cell subsets, which may predict objective response to ICI. Further studies are required to validate immune molecular expression as a prognostic and/or predictive biomarker for long-term outcomes in mUC.

Assessment of the Safety of Pembrolizumab in Patients With HIV and Advanced Cancer-A Phase 1 Study

Importance

Anti-PD-1 (anti-programmed cell death 1) and anti-PD-L1 (anti-programmed cell death ligand 1) regimens are preferred therapies for many cancers, including cancers associated with HIV. However, patients with HIV were excluded from most registered trials.

Objective

The primary objective was to evaluate the safety of pembrolizumab in people with HIV and advanced cancer; the secondary objective was to evaluate tumor responses.

Design, Setting, and Participants

Open-label, nonrandomized, phase 1 multicenter study conducted at 7 Cancer Immunotherapy Trials Network sites. Patients with HIV and advanced cancer as well as a CD4 count greater than or equal to 100 cells/μL, antiretroviral therapy (ART) for 4 or more weeks, and an HIV viral load of less than 200 copies/mL were eligible. Exclusion criteria included uncontrolled hepatitis B or C infection, active immunosuppressive therapy, or a history of autoimmune disease requiring systemic therapy.

Interventions

Pembrolizumab, 200 mg, administered intravenously every 3 weeks for up to 35 doses in 3 CD4 count-defined cohorts. Participants continued ART.

Main Outcomes and Measures

Safety and tolerability were assessed using current NCI Common Terminology Criteria for Adverse Events. Immune-related adverse events grade 2 or higher were considered immune-related events of clinical interest (irECI). Tumor responses were evaluated using standard tumor-specific criteria.

Results

Thirty participants (28 men and 2 women; median [range] age, 57 [39-77] years) were enrolled from April 2016 through March 2018; 6 had Kaposi sarcoma (KS), 5 had non-Hodgkin lymphoma (NHL), and 19 had non-AIDS-defining cancers. Safety was observed over 183 cycles of treatment with pembrolizumab. Most treatment-emergent adverse events at least possibly attributed to pembrolizumab were grade 1 or 2 (n = 22), and 20% (n = 6) were grade 3. The irECI included hypothyroidism (6 participants), pneumonitis (3 participants), rash (2 participants), an elevated aminotransferase/alanine aminotransferase level (1 participant), and a musculoskeletal event (1 participant). One participant with pretreatment KS herpesvirus (KSHV) viremia developed a polyclonal KSHV-associated B-cell lymphoproliferation and died. HIV was controlled in all participants. Increases in CD4 count were not statistically significant (median increase, 19 cells/μL; P = .18). Best tumor responses included complete response (lung, 1 patient), partial response (NHL, 2 patients), stable disease for 24 weeks or more (KS, 2 patients), stable disease for less than 24 weeks (15 patients), and progressive disease (8 patients); 2 patients were not evaluable.

Conclusions and Relevance

Pembrolizumab has acceptable safety in patients with cancer, HIV treated with ART, and a CD4+ T-cell count of greater than 100 cells/μL but may be associated with KSHV-associated B-cell lymphoproliferation. Clinical benefit was noted in lung cancer, NHL, and KS. Anti-PD-1 therapy is appropriate for US Food and Drug Administration-approved indications and clinical trials in this population.

Trial Registration

ClinicalTrials.gov identifier: NCT02595866.

Immune-Checkpoint Protein VISTA Regulates Antitumor Immunity by Controlling Myeloid Cell-Mediated Inflammation and Immunosuppression

Immune-checkpoint protein V-domain immunoglobulin suppressor of T-cell activation (VISTA) controls antitumor immunity and is a valuable target for cancer immunotherapy. This study identified a role of VISTA in regulating Toll-like receptor (TLR) signaling in myeloid cells and controlling myeloid cell-mediated inflammation and immunosuppression. VISTA modulated the polyubiquitination and protein expression of TRAF6. Consequently, VISTA dampened TLR-mediated activation of MAPK/AP-1 and IKK/NF-κB signaling cascades. At cellular levels, VISTA regulated the effector functions of myeloid-derived suppressor cells and tolerogenic dendritic cell (DC) subsets. Blocking VISTA augmented their ability to produce proinflammatory mediators and diminished their T cell-suppressive functions. These myeloid cell-dependent effects resulted in a stimulatory tumor microenvironment that promoted T-cell infiltration and activation. We conclude that VISTA is a critical myeloid cell-intrinsic immune-checkpoint protein and that the reprogramming of tolerogenic myeloid cells following VISTA blockade promotes the development of T cell-mediated antitumor immunity.