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.

Oncologist uptake of comprehensive genomic profile guided targeted therapy

We describe the extent to which comprehensive genomic profiling (CGP) results were used by oncologists to guide targeted therapy selection in a cohort of solid tumor patients tested as part of standard care at Roswell Park Comprehensive Cancer Center June 2016-June 2017, with adequate follow up through September 2018 (n = 620). Overall, 28.4% of CGP tests advised physicians about targeted therapy use supported by companion diagnostic or practice guideline evidence. Post-test targeted therapy uptake was highest for patients in active treatment at the time of order (86% versus 76% of treatment naïve patients), but also took longer to initiate (median 50 days versus 7 days for treatment naïve patients), with few patients (2.6%) receiving targeted agents prior to testing. 100% of patients with resistance variants did not receive targeted agents. Treatment naïve patients received immunotherapy as the most common alternative. When targeted therapy given off-label or in a trial was the best CGP option, (7%) of patients received it. Our data illustrate the appropriate and heterogeneous use of CGP by oncologists as a longitudinal treatment decision tool based on patient history and treatment needs, and that some patients may benefit from testing prior to initiation of other standard treatments.

Abstract 1983: Cancer exosomes immunosuppressive activity in the absence of contaminating soluble factors is multifactorial

Cancer derived exosomes, along with soluble factors such as growth factors, cytokines and chemokines have been identified as integral immunosuppressive pathways employed by cancer cells. Using melanoma cell lines as a model for generating human melanoma exosomes (HMEX), we studied the soluble factors associated with exosome purification methods. A Luminex 13-plex T cell activation kit was used to detect the presence of soluble factors in exosome isolates. We have demonstrated that combining Ultrafiltration and Size Exclusion Chromatography (REIUS method) can yield up to 58-fold more exosomes than ultracentrifugation (UC) with greatly reduced concentrations of contaminating soluble factors (IL-8: 4.6 pg/ml by REIUS versus 489 pg/ml by UC | IL-10: 1,052 pg/ml by REIUS versus 34,500 pg/ml by UC). A novel exosome-based Compact Surface Plasmon Resonance Biosensor demonstrated that REIUS-isolated exosomes abundantly express PD-L1 on their surface compared to UC-purified exosomes. These HMEX significantly inhibited a cloned NY-ESO tumor antigen-specific patient derived T cell function when co-cultured with a NY-ESO positive melanoma cell line for 4 h (IFN-γ positive T cell population: 78.5 ± 0.03 % versus 49.05 ± 0.07 %). Blocking with anti-PDL1 or anti-IL-10 failed to restore T cell function (IFN-γ production), while both anti-PD-L1 and anti-IL-10 antibodies partially reverse this suppression, thereby identifying IL-10 and PD-L1 as a novel collaborating inhibitory pathway. Taken together, we report that different exosome isolation methods impact the nature of the exosomes and contaminating soluble factors and should be chosen with caution. In addition, our data suggests a novel role for tumor-derived exosomes in the IL-10 and PD1-PDL1 axis crosstalk that impacts functional activity of T cells.

Citation Format: Shin La Shu, Junko Matsuzaki, Cheryl Allen, Yunchen Yang, Edward Hurley, Kunle Odunsi, Yun Wu, Marc S. Ernstoff. Cancer exosomes immunosuppressive activity in the absence of contaminating soluble factors is multifactorial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1983.

Efficacy and safety of the combination of nivolumab (NIVO) plus ipilimumab (IPI) in patients with symptomatic melanoma brain metastases (CheckMate 204)

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Background: We previously reported efficacy and safety of NIVO+IPI in patients (pts) with untreated, asymptomatic, melanoma brain metastases (MBM) from the CheckMate 204 study. Here, we provide the first report of NIVO+IPI in pts with symptomatic MBM, and report updated data in pts with asymptomatic MBM. Methods: In this phase II trial, pts with ≥1 measurable, nonirradiated MBM 0.5–3.0 cm were enrolled into two cohorts: (1) those with no neurologic symptoms or steroid Rx (asymptomatic; cohort A); and (2) those with neurologic symptoms, whether or not they were receiving steroid Rx (symptomatic; cohort B). In both cohorts, pts received NIVO 1 mg/kg + IPI 3 mg/kg Q3W × 4, then NIVO 3 mg/kg Q2W until progression or toxicity. The primary endpoint was intracranial clinical benefit rate (CBR; proportion of pts with complete response [CR] + partial response [PR] + stable disease [SD] ≥6 mo). As of the clinical cutoff date on May 1, 2018, all treated pts (101 in cohort A and 18 in cohort B) had been followed for ~6 mo or longer. Results: In this updated analysis of cohort A (median follow-up of 20.6 mo), the CBR was 58.4% (Table). In cohort B, pts received a median of 1 NIVO+IPI dose and 2 of 18 pts (11%) received all 4 doses. At a median follow-up of 5.2 months in cohort B, intracranial objective response rate was 16.7% and the CBR was 22.2%. Grade 3/4 adverse events occurred in 54.5% of pts in cohort A and in 55.6% of pts in cohort B (6.9% and 16.7% in the nervous system, respectively), with one death related to treatment in cohort A (immune-related myocarditis). Conclusions: In pts with asymptomatic MBM, our updated results show a high rate of durable intracranial responses, further supporting NIVO+IPI as a first-line treatment in this population. Intracranial antitumor activity was observed with NIVO+IPI in pts with symptomatic MBM, but further study is needed to understand the biologic mechanisms of resistance to immunotherapy and to improve treatments in this challenging population. Clinical trial information: NCT02320058. [Table: see text]

Intravenous administration of ALKS 4230 as monotherapy and in combination with pembrolizumab in a phase I study of patients with advanced solid tumors

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Background: ALKS 4230 is a fusion protein of circularly permuted IL-2 and IL-2 Receptor (IL-2R) α designed to selectively bind the intermediate-affinity (ia) IL-2R, comprised of IL-2Rβ and γc, for activation of CD8+ T cells and NK cells, which drive antitumor immune responses. In contrast, unmodified IL-2 activates high-affinity (ha) IL-2R, driving the expansion of immunosuppressive CD4+ regulatory T cells (Tregs) at concentrations below those that activate iaIL-2R expressing cells. Binding of IL-2 to haIL-2R on endothelial cells may contribute to capillary leak syndrome seen with high-dose IL-2. Thus, selective activation of the iaIL-2R by ALKS 4230 has the potential to enhance tumor killing and improve tolerability. ALKS 4230 has previously been shown to improve antitumor activity relative to IL-2 in murine models. In this clinical study, ALKS 4230 will be assessed as monotherapy and in combination with anti-PD-1 therapy. Methods: ALKS 4230 is being studied in adults with advanced solid tumors in a phase I first-in-human trial designed primarily to assess the safety of ALKS 4230 alone and with pembrolizumab. The study will also determine a monotherapy recommended phase 2 dose (RP2D) and characterize pharmacokinetics, pharmacodynamics (PD), immunogenicity, and evidence of anti-tumor activity. It will be conducted in 3 parts: monotherapy dose escalation (Part A), monotherapy dose expansion at the RP2D (Part B), and combination therapy with pembrolizumab (Part C). ALKS 4230 is administered as a 30 minute IV infusion once daily for five days in each 14 or 21 day cycle. Part A is inpatient. Eligibility requires ECOG PS 0-1 and adequate bone marrow, liver and kidney function. Part B will enroll 21 patients each in renal cell carcinoma and melanoma cohorts. Part C will enroll up to 79 patients total into 3 cohorts based on tumor type and prior anti-PD-1 therapy; a 4th cohort will enroll patients from Part A or B who received at least 4 cycles of ALKS 4230 or experienced disease progression on monotherapy. The primary PD endpoint is change from baseline in CD8+ T, NK, and Treg cell counts. Inflammatory cytokine levels will also be measured. Parts A and C are currently enrolling. Clinical trial information: NCT02799095.

A phase I study of neoadjuvant combination immunotherapy in locally/regionally advanced melanoma

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Background: A trial of neoadjuvant pembrolizumab (P) in combination with high dose interferon-α (HDI) in high-risk patients (pts) with locoregionally advanced melanoma (mel) has completed enrollment. Methods: Primary endpoint: safety of combination P-HDI. Pts were treated with P x 2 doses followed by definitive surgery, then x1 year. HDI was given concurrently, and both agents were per standard regimen. Tumor and blood samples were obtained at baseline and at surgery (wk 6-8), blood at 6 wks, 3,6,12 months (mos). Results: 30 pts were treated (22 male, 8 female, age 26-83). 16 had cutaneous primary, 3 mucosal, 11 unknown. At enrollment, 16 had recurrent disease, 6 received prior adjuvant therapy with ipilimumab (4) or HDI (2). 16 had AJCC 7 stage IIIB, 9 IIIC, 5 IV. 332 P cycles have been delivered (median 13), 496 doses of HDI induction (median 17), 1329 doses of HDI maintenance (median 44). HDI was dose reduced in 20 pts, discontinued in 27, P discontinued in 8. Radiologic preoperative RR was 77% (95% CI, 59-88) (6 CR, 17 PR). 20% (6) had SD and 1 had PD. All pts underwent definitive surgery. The pathologic complete response (pCR) of 26 pts was 32% (95% CI, 18-51). 6 pts recurred and 3 died. No pt with pCR has recurred. Median f/u time is 17.4 mos, median PFS/OS not reached. Most common grade (Gr) 3 toxicities: hypophosphatemia (10; 33%), fatigue (10; 33%), ↑CPK (6; 20%), ↑lipase (4; 13%). 3 Gr 4 events (↑CPK, hyperglycemia, lymphocyte count decreased). 1 suspected grade 5 event occurred 6 months after completion of therapy. PD-L1 expression at baseline did not correlate with clinical outcomes. In 8 pts with pre and post treatment tumor samples, IHC expression of PD-1, PD-L1, CD11b, CD8, Foxp3 and CD25 increased post-treatment (p < 0.05). Conclusions: Neoadjuvant P-HDI has promising clinical activity, although treatment is limited by HDI toxicity. Treatment increases the immune cell infiltrate, and outcomes do not correlate with baseline expression of PD-L1. Longer follow up and further mechanistic studies are underway. Clinical trial information: NCT02339324.

Phase I study of pembrolizumab in people with HIV and cancer

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Background: People with HIV have been excluded from immuno-oncology (IO) studies. Anti- PD-1/PD-L1 therapies are approved for a growing number of cancers. We evaluated pembrolizumab (pembro) in people with HIV and cancer. Methods: CITN-12 is a multicenter phase 1 trial. Key eligibility: advanced cancer; ECOG ≤1; CD4 ≥100 cells/μL; ≥4 weeks antiretroviral therapy (ART), HIV viral load (VL) < 200 copies/mL. Exclusion: uncontrolled HBV/HCV, autoimmune disease. Participants (pts) accrued into CD4 based cohorts (C): C1 100-199; C2 200-350; C3 > 350 CD4 cells/μL. Pembro 200 mg IV administered Q3W for up to 35 doses. Adverse events (AE) evaluated by CTCAE. Immune related AE ≥ grade (Gr) 2 were events of clinical interest (irECI). Clinical benefit (tumor shrinkage or stable disease [SD] ≥24 weeks) was estimated. Data were locked for safety analysis and publication once C2 and C3 completed accrual and all pts completed ≥2 cycles. Accrual continued for 6 C1 pts and a new phase 1b Kaposi sarcoma (KS) cohort (C4). Results: 30 pts, characteristics: C1 (6), C2 and 3 (12 each), median (med) age 57 years (range 39-77), 28 men, 2 women, 60% White, 30% Black, 10% Hispanic. Med CD4 285 cells/μL (132 - 966). Cancers: KS (6), non-Hodgkin lymphoma (NHL) (5), non-AIDS defining (19) – most common: anal (6) and squamous cell skin (3). Prior radiation (19), med prior systemic therapies 2 (0-8). Safety observed over 183 cycles, med 5 (1-32). Treatment emergent AE ≥ possibly attributed to pembro mostly Gr 1-2, with 20% of pts having Gr 3. irECI: hypothyroidism (6), elevated AST/ALT (1), pneumonitis (3), rash (2), musculoskeletal (1).1 KS pt developed KSHV-associated multicentric Castleman disease (KSHV-MCD) and died of the AE. HIV was controlled and increasing CD4 counts were observed. Best response: complete (lung, 1), partial (NHL, 2), SD ≥24 weeks (KS, 2), SD < 24 weeks (13), progressive disease (10), not evaluable (2). Conclusions: Pembro has acceptable safety in cancer pts with HIV on ART and > 100 CD4 cells/µL, similar to patients without HIV. Anti-PD-1 may unmask KSHV-MCD and such KSHV-viremic patients should be excluded. Clinical benefit was noted in several tumor types. Anti-PD1 is appropriate for FDA-approved indications in this population. Patients with HIV meeting appropriate eligibility criteria should be included in IO studies. Clinical trial information: NCT02595866.

Validation of Melanoma Immune Profile (MIP), a Prognostic Immune Gene Prediction Score for Stage II-III Melanoma

PURPOSE

Biomarkers are needed to stratify patients with stage II-III melanoma for clinical trials of adjuvant therapy because, while immunotherapy is protective, it also confers the risk of severe toxicity. We previously defined and validated a 53-immune gene melanoma immune profile (MIP) predictive both of distant metastatic recurrence and of disease-specific survival (DSS). Here, we test MIP on a third independent population.

EXPERIMENTAL DESIGN

A retrospective cohort of 78 patients with stage II-III primary melanoma was analyzed using the NanoString assay to measure expression of 53 target genes, and MIP score was calculated. Statistical analysis correlating MIP with DSS, overall survival, distant metastatic recurrence, and distant metastasis-free interval was performed using ROC curves, Kaplan-Meier curves, and standard univariable and multivariable Cox proportional hazards models.

RESULTS

MIP significantly distinguished patients with distant metastatic recurrence from those without distant metastatic recurrence using ROC curve analysis (AUC = 0.695; P = 0.008). We defined high- and low-risk groups based on the cutoff defined by this ROC curve and find that MIP correlates with both DSS and overall survival by ROC curve analysis (AUC = 0.719; P = 0.004 and AUC = 0.698; P = 0.004, respectively). Univariable Cox regression reveals that a high-risk MIP score correlates with DSS (P = 0.015; HR = 3.2).

CONCLUSIONS

MIP identifies patients with low risk of death from melanoma and may constitute a clinical tool to stratify patients with stage II-III melanoma for enrollment in clinical trials.

Cardiac Toxicity Associated with Immune Checkpoint Inhibitors: Case Series and Review of the Literature

The development of immune checkpoint inhibitors (ICIs) has revolutionized the treatment of patients with advanced stage cancers. However, immune-related adverse events are frequently observed. Cardiac toxicity from ICI therapy can range from asymptomatic troponin-I elevations to conduction abnormalities of the heart and even fulminant myocarditis. Although rare, myocarditis is a potentially fatal adverse effect of ICI therapy. We present a series of five cases of ICI-related cardio-toxicity diagnosed and managed at Roswell Park Comprehensive Cancer Center along with a review of published case reports in the literature. Our series highlights the importance of high clinical suspicion, early diagnosis of myocarditis, and prompt initiation of immunosuppressive therapy.

Correction to: Safety and efficacy of nivolumab in combination with sunitinib or pazopanib in advanced or metastatic renal cell carcinoma: the CheckMate 016 study

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Management of Immunotherapy-Related Toxicities, Version 1.2019, NCCN Clinical Practice Guidelines in Oncology

The aim of the NCCN Guidelines for Management of Immunotherapy-Related Toxicities is to provide guidance on the management of immune-related adverse events resulting from cancer immunotherapy. The NCCN Management of Immunotherapy-Related Toxicities Panel is an interdisciplinary group of representatives from NCCN Member Institutions and ASCO, consisting of medical and hematologic oncologists with expertise in a wide array of disease sites, and experts from the fields of dermatology, gastroenterology, neuro-oncology, nephrology, emergency medicine, cardiology, oncology nursing, and patient advocacy. Several panel representatives are members of the Society for Immunotherapy of Cancer (SITC). The initial version of the NCCN Guidelines was designed in general alignment with recommendations published by ASCO and SITC. The content featured in this issue is an excerpt of the recommendations for managing toxicity related to immune checkpoint blockade and a review of existing evidence. For the full version of the NCCN Guidelines, including recommendations for managing toxicities related to chimeric antigen receptor T-cell therapy, visitNCCN.org.

Safety and efficacy of cryopreserved autologous tumor infiltrating lymphocyte therapy (LN-144, lifileucel) in advanced metastatic melanoma patients previously treated with at least one prior systemic therapy

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Background: While immunotherapies including checkpoint inhibitors and targeted therapies (BRAF/MEK inhibitors) are options for patients with metastatic melanoma, many patients still develop progressive disease. These patients have few treatment options available including high dose IL-2 and chemotherapy with reported second line response rates of 4-10%. Adoptive cell therapy utilizing tumor-infiltrating lymphocytes (TIL) is recognized as an effective treatment in metastatic melanoma, able to elicit durable and complete responses in even heavily pretreated patients. We provide preliminary data for lifileucel TIL (LN-144) in heavily pre-treated metastatic melanoma patients who progressed on multiple checkpoint and BRAF/MEK inhibitors. Methods: C-144-01 is an ongoing global Phase 2, open-label, multicenter study of efficacy and safety of lifileucel in patients with unresectable metastatic melanoma. We report on Cohort 2 (N = 47) patients who received cryopreserved lifileucel. Tumors resected at local institutions were processed at central GMP facilities in a 22-day manufacturing process. The final product was cryopreserved and shipped to sites. Patients received a one week cyclophosphamide/fludarabine preconditioning lymphodepletion regimen, a single lifileucel infusion, followed by up to 6 doses of iv IL-2 (600,000 IU/kg). Results: Patients with Stage IIIC/IV melanoma had 3.3 mean prior therapies (range: 1-9) and high baseline tumor burden, reflected by a mean sum of diameters of target lesions of 112 mm. Preliminary efficacy results: ORR = 38% (1 CR, 13 PR, 4 uPR), DCR = 77%, and median DOR 6.4 mo (range: 1.3 to 13.7) with median follow-up 6.0 mo. Longer follow-up led to improved responses in some patients including the CR. Frequency of AEs decreased over time, a potentially important benefit of one-time TIL treatment. Conclusions: Preliminary data support lifileucel TIL as an efficacious and well-tolerated therapeutic option for patients with metastatic melanoma who have failed multiple lines of prior therapies including checkpoint inhibitors and BRAF/MEK inhibitors. Clinical trial information: NCT02360579.

Treatment recommendations to cancer patients in the context of FDA guidance for next generation sequencing

Background

Regulatory approval of next generation sequencing (NGS) by the FDA is advancing the use of genomic-based precision medicine for the therapeutic management of cancer as standard care. Recent FDA guidance for the classification of genomic variants based on clinical evidence to aid clinicians in understanding the actionability of identified variants provided by comprehensive NGS panels has also been set forth. In this retrospective analysis, we interpreted and applied the FDA variant classification guidance to comprehensive NGS testing performed for advanced cancer patients and assessed oncologist agreement with NGS test treatment recommendations.

Methods

NGS comprehensive genomic profiling was performed in a CLIA certified lab (657 completed tests for 646 patients treated at Roswell Park Comprehensive Cancer Center) between June 2016 and June 2017. Physician treatment recommendations made within 120 days post-test were gathered from tested patients’ medical records and classified as targeted therapy, precision medicine clinical trial, immunotherapy, hormonal therapy, chemotherapy/radiation, surgery, transplant, or non-therapeutic (hospice, surveillance, or palliative care). Agreement between NGS test report targeted therapy recommendations based on the FDA variant classification and physician targeted therapy treatment recommendations were evaluated.

Results

Excluding variants contraindicating targeted therapy (i.e., KRAS or NRAS mutations), at least one variant with FDA level 1 companion diagnostic supporting evidence as the most actionable was identified in 14% of tests, with physicians most frequently recommending targeted therapy (48%) for patients with these results. This stands in contrast to physicians recommending targeted therapy based on test results with FDA level 2 (practice guideline) or FDA level 3 (clinical trial or off label) evidence as the most actionable result (11 and 4%, respectively).

Conclusions

We found an appropriate “dose-response” relationship between the strength of clinical evidence supporting biomarker-directed targeted therapy based on application of FDA guidance for NGS test variant classification, and subsequent treatment recommendations made by treating physicians. In view of recent changes at FDA, it is paramount to define regulatory grounds and medical policy coverage for NGS testing based on this guidance.

A Review of Exosomes and their Role in The Tumor Microenvironment and Host-Tumor "Macroenvironment"

Tumor-derived exosomes (TEX) are important intercellular messengers that contribute to tumorigenesis and metastasis through a variety of mechanisms such as immunosuppression and metabolic reprogramming that generate a pre-metastatic niche favorable to tumor progression. Our lab has contributed further to the understanding of the miRNA payloads in TEX by demonstrating that human melanoma-derived exosome (HMEX) associated miRNAs contribute to the metabolic reprogramming of normal stroma. This mini-review highlights the role of TEX in the tumor microenvironment (TME) and the hypothesis that exosomes may also generate a host-tumor "macroenvironment" beyond the TME through their miRNA and protein payloads, so to speak "fertilizing the soil for cancer seeding."

Mechanism of resistance to immune checkpoint inhibitors

Immune checkpoint inhibitors (ICI) have revolutionized the management of cancer over the last decade. Instead of targeting the cancer cell directly these agents work by augmenting the immune response towards tumor. Although they are associated with improved responses compared to traditional treatments in several malignancies, a majority of the patients don't respond to ICIs even when used in the frontline setting. In patients who do respond, a significant number eventually develop resistance. We will review ICI mechanisms of action and resistance. We will also discuss new therapeutic options and combinations with other agents that are currently being evaluated to overcome resistance to ICI.

Where We Stand With Immunotherapy in Colorectal Cancer: Deficient Mismatch Repair, Proficient Mismatch Repair, and Toxicity Management

With the recent U.S. Food and Drug Administration approvals of pembrolizumab and nivolumab for refractory deficient mismatch repair metastatic colorectal cancer, immune checkpoint inhibitors have now entered into clinical care for gastrointestinal cancers. Extensive ongoing efforts are exploring additional combinations of therapy in both deficient and proficient mismatch repair colorectal cancer. This review will outline the current status of such efforts and discuss the critical aspects of recognition and management of immune-related toxicities from checkpoint inhibitors.

NCI 8628: A randomized phase 2 study of ziv-aflibercept and high-dose interleukin 2 or high-dose interleukin 2 alone for inoperable stage III or IV melanoma

BACKGROUND

Interleukin 2 (IL-2) is a growth factor for T and natural killer cells, promotes proinflammatory cytokines, and can lead to durable responses in patients with melanoma. Vascular endothelial growth factor (VEGF) promotes angiogenesis and modulates host innate and adaptive immunity. High VEGF levels were found to be associated with nonresponse to IL-2. Ziv-aflibercept may deplete VEGF and thereby enhance antitumor T-cell responses, thus supporting a combination immunotherapeutic strategy with IL-2.

METHODS

NCI 8628 was a phase 2 trial of ziv-aflibercept and IL-2 (arm A) versus IL-2 alone (arm B) randomized at 2:1, respectively. Eligible patients had inoperable American Joint Committee on Cancer stage III or stage IV melanoma. The primary endpoint was progression-free survival (PFS).

RESULTS

A total of 89 patients were enrolled and 84 patients were treated. The median follow-up was 41.4 months. Among treated patients (55 patients in arm A and 29 patients in arm B), PFS was significantly improved in favor of arm A, with a median of 6.9 months (95% confidence interval [95% CI], 4.1-8.7 months) versus 2.3 months (95% CI, 1.6-3.5 months) (P<.001). No significant difference was noted with regard to overall survival, with a median of 26.9 months (95% CI, 14.4-63.6 months) for arm A and 24.2 months (95% CI, 11.3-36.4 months) for arm B. The response rate (according to Response Evaluation Criteria In Solid Tumors [RECIST]) was 22% in arm A (4 complete responses [CRs] and 8 partial responses [PRs]) and 17% in arm B (1 CR and 4 PRs). Stable disease or PR or CR was noted in 65% of patients in arm A and 48% of patients in arm B. The combination was found to be superior to monotherapy in patients with high and low levels of serum VEGF and VEGF receptor 2. Adverse events were consistent with the expected profiles of monotherapy with IL-2 and ziv-aflibercept.

CONCLUSIONS

Ziv-aflibercept and IL-2 were found to significantly improve PFS compared with IL-2 alone, thereby meeting the primary endpoint of the current study. These findings support further study of immunotherapeutic combination strategies involving VEGF inhibitors.

Safety and efficacy of nivolumab in combination with sunitinib or pazopanib in advanced or metastatic renal cell carcinoma: the CheckMate 016 study

BACKGROUND

Combination treatment with immune checkpoint inhibitors and antiangiogenic drugs has shown encouraging preliminary antitumor activity across various tumor types including advanced or metastatic renal cell carcinoma (aRCC). The open-label, parallel-cohort, dose-escalation, phase I CheckMate 016 study evaluated the efficacy and safety of nivolumab in combination with antiangiogenic tyrosine kinase inhibitors or ipilimumab. Long-term outcomes from this study for the combination of nivolumab plus sunitinib or pazopanib in aRCC are presented.

METHODS

Patients with aRCC received nivolumab plus either sunitinib (50 mg/day, 4 weeks on/2 weeks off; N + S) or pazopanib (800 mg/day; N + P) until progression/unacceptable toxicity. The nivolumab starting dose was 2 mg/kg every 3 weeks, with planned escalation to 5 mg/kg every 3 weeks. Primary endpoints were safety and tolerability; antitumor activity was a secondary endpoint.

RESULTS

Arm N + S enrolled 33 patients, 19 of whom were treatment-naïve; this arm advanced to the expansion phase. Median follow-up was 50.0 months. Patients experienced high frequencies of adverse events (AEs) including treatment-related AEs (100%), grade 3/4 treatment-related AEs (82%), and treatment-related AEs leading to discontinuation (39%). Investigator-assessed objective response rate (ORR) was 55% (18/33) and median progression-free survival (PFS) was 12.7 months. Median overall survival (OS) was not reached. Arm N + P enrolled 20 patients, all had ≥1 prior systemic therapy; this arm was closed due to dose-limiting toxicities and did not proceed to expansion. Median follow-up was 27.1 months. Patients treated with N + P experienced high frequencies of AEs including treatment-related AEs (100%), grade 3/4 treatment-related AEs (70%), and treatment-related AEs leading to discontinuation (25%). Investigator-assessed ORR was 45% (9/20) and median PFS was 7.2 months. Median OS was 27.9 months.

CONCLUSIONS

The addition of standard doses of sunitinib or pazopanib to nivolumab resulted in a high incidence of high-grade toxicities limiting future development of either combination regimen. While there was no adverse impact on response and the OS outcome was notable, the findings suggest that the success of combination regimens based on immune checkpoint inhibitors and antiangiogenic drugs may be dependent on careful selection of the antiangiogenic component and dose.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT01472081 . Registered 16 November 2011.

Metabolic reprogramming of stromal fibroblasts by melanoma exosome microRNA favours a pre-metastatic microenvironment

Local acidification of stroma is proposed to favour pre-metastatic niche formation but the mechanism of initiation is unclear. We investigated whether Human Melanoma-derived exosomes (HMEX) could reprogram human adult dermal fibroblasts (HADF) and cause extracellular acidification. HMEX were isolated from supernatants of six melanoma cell lines (3 BRAF V600E mutant cell lines and 3 BRAF wild-type cell lines) using ultracentrifugation or Size Exclusion Chromatography (SEC). Rapid uptake of exosomes by HADF was demonstrated following 18 hours co-incubation. Exposure of HDAF to HMEX leads to an increase in aerobic glycolysis and decrease in oxidative phosphorylation (OXPHOS) in HADF, consequently increasing extracellular acidification. Using a novel immuno-biochip, exosomal miR-155 and miR-210 were detected in HMEX. These miRNAs were present in HMEX from all six melanoma cell lines and were instrumental in promoting glycolysis and inhibiting OXPHOS in tumour cells. Inhibition of miR-155 and miR-210 activity by transfection of miRNA inhibitors into HMEX reversed the exosome-induced metabolic reprogramming of HADF. The data indicate that melanoma-derived exosomes modulate stromal cell metabolism and may contribute to the creation of a pre-metastatic niche that promotes the development of metastasis.

Combined Nivolumab and Ipilimumab in Melanoma Metastatic to the Brain

BACKGROUND

Brain metastases are a common cause of disabling neurologic complications and death in patients with metastatic melanoma. Previous studies of nivolumab combined with ipilimumab in metastatic melanoma have excluded patients with untreated brain metastases. We evaluated the efficacy and safety of nivolumab plus ipilimumab in patients with melanoma who had untreated brain metastases.

METHODS

In this open-label, multicenter, phase 2 study, patients with metastatic melanoma and at least one measurable, nonirradiated brain metastasis (tumor diameter, 0.5 to 3 cm) and no neurologic symptoms received nivolumab (1 mg per kilogram of body weight) plus ipilimumab (3 mg per kilogram) every 3 weeks for up to four doses, followed by nivolumab (3 mg per kilogram) every 2 weeks until progression or unacceptable toxic effects. The primary end point was the rate of intracranial clinical benefit, defined as the percentage of patients who had stable disease for at least 6 months, complete response, or partial response.

RESULTS

Among 94 patients with a median follow-up of 14.0 months, the rate of intracranial clinical benefit was 57% (95% confidence interval [CI], 47 to 68); the rate of complete response was 26%, the rate of partial response was 30%, and the rate of stable disease for at least 6 months was 2%. The rate of extracranial clinical benefit was 56% (95% CI, 46 to 67). Treatment-related grade 3 or 4 adverse events were reported in 55% of patients, including events involving the central nervous system in 7%. One patient died from immune-related myocarditis. The safety profile of the regimen was similar to that reported in patients with melanoma who do not have brain metastases.

CONCLUSIONS

Nivolumab combined with ipilimumab had clinically meaningful intracranial efficacy, concordant with extracranial activity, in patients with melanoma who had untreated brain metastases. (Funded by Bristol-Myers Squibb and the National Cancer Institute; CheckMate 204 ClinicalTrials.gov number, NCT02320058 .).

A multi-center phase II study of high dose interleukin-2 sequenced with vemurafenib in patients with BRAF-V600 mutation positive metastatic melanoma

BACKGROUND

Preclinical studies suggest that BRAF inhibitors enhance anti-tumor immunity and antigen presentation. Combination BRAF inhibition with immunotherapy is an appealing therapeutic approach. We sequenced vemurafenib with HD IL-2 in patients with BRAF-mutated metastatic melanoma to improve long term outcomes.

METHODS

Eligible patients were HD IL-2 eligible with metastatic BRAF V600 mutated melanoma. Cohort 1 was treatment naïve and received vemurafenib 960 mg BID for 6 weeks before HD IL-2. Cohort 2 received vemurafenib for 7-18 weeks before enrollment. Both cohorts received HD IL-2 at 600,000 IU/kg every 8 h days 1-5 and days 15-19. The primary objective was to assess complete responses (CR) at 10 weeks ±3 (assessment 1) and 26 weeks ±3 (assessment 2) from the start of HD IL-2.

RESULTS

Fifty-three patients were enrolled, (cohort 1, n = 38; cohort 2, n = 15). Of these, 39 underwent assessment 1 and 15 assessment 2. The CR rate at assessment 1 was 10% (95% CI 3-24) for both cohorts combined, and 27% (95% CI 8-55) at assessment 2. Three-year survival was 30 and 27% for cohort 1 and cohort 2, respectively. No unexpected toxicities occurred. A shift in the melanoma treatment landscape during this trial adversely affected accrual, leading to early trial closure.

CONCLUSIONS

Vemurafenib in sequence with HD IL-2 did not change the known toxicity profile for either agent. Lower than expected response rates to vemurafenib were observed. Overall response rates and durability of responses appear similar to that observed with HD IL-2 alone.

TRIAL REGISTRATION

NCTN, NCT01683188. Registered 11 September 2012, http://www.clinicaltrials.gov/NCT01683188.

Phase I Trial of ALT-803, A Novel Recombinant IL15 Complex, in Patients with Advanced Solid Tumors

Purpose: IL15 induces the activation and proliferation of natural killer (NK) and memory CD8⁺ T cells and has preclinical antitumor activity. Given the superior activity and favorable kinetics of ALT-803 (IL15N72D:IL15RαSu/IgG1 Fc complex) over recombinant human IL15 (rhIL15) in animal models, we performed this first-in-human phase I trial of ALT-803 in patients with advanced solid tumors.Patients and Methods: Patients with incurable advanced melanoma, renal cell, non-small cell lung, and head and neck cancer were treated with ALT-803 0.3 to 6 μg/kg weekly intravenously or 6 to 20 μg/kg weekly subcutaneously for 4 consecutive weeks, every 6 weeks. Immune correlates included pharmacokinetics, immunogenicity, and lymphocyte expansion and function. Clinical endpoints were toxicity and antitumor activity.Results: Twenty-four patients were enrolled; 11 received intravenous and 13 received subcutaneous ALT-803. Of these patients, nine had melanoma, six renal, three head and neck, and six lung cancer. Although total lymphocyte and CD8⁺ T-cell expansion were modest, NK cell numbers rose significantly. Neither anti-ALT-803 antibodies nor clinical activity were observed. Overall, ALT-803 was well tolerated, with adverse effects including fatigue and nausea most commonly with intravenous administration, whereas painful injection site wheal was reported most commonly with subcutaneous ALT-803.Conclusions: Subcutaneous ALT-803 produced the expected NK cell expansion and was well tolerated with minimal cytokine toxicities and a strong local inflammatory reaction at injection sites in patients with advanced cancer. These data, together with compelling evidence of synergy in preclinical and clinical studies, provide the rationale for combining ALT-803 with other anticancer agents. Clin Cancer Res; 24(22); 5552-61. ©2018 AACR.

VISTA expression on tumor-infiltrating inflammatory cells in primary cutaneous melanoma correlates with poor disease-specific survival

Adaptive immune responses contribute to the pathogenesis of melanoma by facilitating immune evasion. V-domain Ig suppressor of T-cell activation (VISTA) is a potent negative regulator of T-cell function and is expressed at high levels on monocytes, granulocytes, and macrophages, and at lower densities on T-cell populations within the tumor microenvironment. In this study, 85 primary melanoma specimens were selected from pathology tissue archives and immunohistochemically stained for CD3, PD-1, PD-L1, and VISTA. Pearson's correlation coefficients identified associations in expression between VISTA and myeloid infiltrate (r = 0.28, p = 0.009) and the density of PD-1+ inflammatory cells (r = 0.31, p = 0.005). The presence of VISTA was associated with a significantly worse disease-specific survival in univariate analysis (hazard ratio = 3.57, p = 0.005) and multivariate analysis (hazard ratio = 3.02, p = 0.02). Our findings show that VISTA expression is an independent negative prognostic factor in primary cutaneous melanoma and suggests its potential as an adjuvant immunotherapeutic intervention in the future.

Abstract 5087: Human melanoma exosomes induce metabolic reprogramming in human adult dermal fibroblasts

The “seed and soil” hypothesis of cancer metastasis has led us to examine the role of tumor-derived exosomes on reprogramming stromal cells composing the tumor microenvironment. We used human adult dermal fibroblasts (HADF) in vitro as a model of the premetastatic niche. Specifically, we determined the role of human melanoma-derived exosomes (HMEX) on governing metabolic reprogramming of healthy HADF. HMEX from six melanoma cell lines (3 BRAF V600E mutant cell lines (526-mel, 888-mel and Hs 294T) and 3 BRAF wild-type cell lines (1300-mel, 2183-Her4 and HMCB)) were purified by size-exclusion chromatography. Using the fluorescent tag CellVue (Maroon) we demonstrated via ImageStream that HMEXs are rapidly taken up by HADF. Following 18 hours of exposure to HMEX, HADF increased aerobic glycolysis and reduced oxidative phosphorylation (OXPHOS) in vitro, as measured by Agilent Seahorse XFe96. We have also developed an immuno-biochip that captures exosomes via anti-CD63 antibodies and simultaneously detects exosomal microRNAs by cationic lipoplex nanoparticles (tCLN) containing molecular beacons. With this immuno-biochip, we demonstrated the presence of microRNAs miR-155 and miR-210 in HMEX, both of which work in concert to promote glycolysis and inhibit OXPHOS. The result has been consistent across all HMEXs from the six different melanoma cell lines. Our findings reveal a correlation between metabolic function and the presence of metabolically active microRNAs in HMEX that control aerobic glycolysis and OXPHOS of normal fibroblasts. Melanoma exosomes are potentially key players in promoting tumor progression by modulating normal stromal cell metabolism and creating an environment that is conducive to metastasis.

Oxygen Consumption Rate (OCR) pmol/minHADF onlyHADF + HMEX 17.5 μgHADF + HMEX 25 μgHADF + HMEX 50μgHADF + HMEX100μgBasal OCR52.6753.5850.9638.2031.56

Citation Format: Shin La Shu, Cheryl L. Allen, Yunchen Yang, Orla Maguire, Hans Minderman, Arindam Sen, Michael J. Ciesielski, Katherine A. Collins, Peter J. Bush, Martin Morgan, Yun Wu, Richard B. Bankert, Marc S. Ernstoff. Human melanoma exosomes induce metabolic reprogramming in human adult dermal fibroblasts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5087.