Search

Supplemental Table 1. Adverse events observed and adjudicated as possibly, probably or definitely related to therapy (n = 19).

Supplementary Data from A Randomized, Double-Blind, Placebo-Controlled, Phase II Study Comparing the Tolerability and Efficacy of Ipilimumab Administered with or without Prophylactic Budesonide in Patients with Unresectable Stage III or IV Melanoma

Purpose: Diarrhea (with or without colitis) is an immune-related adverse event (irAE) associated with ipilimumab. A randomized, double-blind, placebo-controlled, multicenter, multinational phase II trial was conducted to determine whether prophylactic budesonide (Entocort EC), a nonabsorbed oral steroid, reduced the rate of grade ≥2 diarrhea in ipilimumab-treated patients with advanced melanoma.Experimental Design: Previously treated and treatment-naïve patients (N = 115) with unresectable stage III or IV melanoma received open-label ipilimumab (10 mg/kg every 3 weeks for four doses) with daily blinded budesonide (group A) or placebo (group B) through week 16. The first scheduled tumor evaluation was at week 12; eligible patients received maintenance treatment starting at week 24. Diarrhea was assessed using Common Terminology Criteria for Adverse Events (CTCAE) 3.0. Patients kept a diary describing their bowel habits.Results: Budesonide did not affect the rate of grade ≥2 diarrhea, which occurred in 32.7% and 35.0% of patients in groups A and B, respectively. There were no bowel perforations or treatment-related deaths. Best overall response rates were 12.1% in group A and 15.8% in group B, with a median overall survival of 17.7 and 19.3 months, respectively. Within each group, the disease control rate was higher in patients with grade 3 to 4 irAEs than in patients with grade 0 to 2 irAEs, although many patients with grade 1 to 2 irAEs experienced clinical benefit. Novel patterns of response to ipilimumab were observed.Conclusions: Ipilimumab shows activity in advanced melanoma, with encouraging survival and manageable adverse events. Budesonide should not be used prophylactically for grade ≥2 diarrhea associated with ipilimumab therapy. (Clin Cancer Res 2009;15(17):5591–8)

Purpose: Dabrafenib is a selective, potent ATP-competitive inhibitor of the BRAFV600-mutant kinase that has demonstrated efficacy in clinical trials. We report the rationale for dose selection in the first-in-human study of dabrafenib, including pharmacokinetics, tissue pharmacodynamics, 2[18F]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) pharmacodynamics, and dose–response relationship.Experimental Design: Dabrafenib was administered orally once, twice (BID), or three times daily (TID). Selected dose cohorts were expanded to collect adequate data on safety, pharmacokinetics, or pharmacodynamics. A recommended phase II dose (RP2D) was chosen based on safety, pharmacokinetic, pharmacodynamic, and response data.Results: One hundred and eighty-four patients were enrolled and treated with doses ranging from 12 mg once daily to 300 mg BID in 10 cohorts. Pharmacokinetic assessment of dabrafenib demonstrated a less-than-dose-proportional increase in exposure after repeat dosing above 150 mg BID. Similar to parent drug concentrations, exposure for all metabolites demonstrated less-than-dose-proportional increases. Predicted target inhibition of pERK (>80%) was achieved at 150 mg BID, with a similar magnitude of inhibition at higher doses in BRAFV600 mutation melanoma biopsy samples. Although there was large variability between patients, FDG uptake decreased with higher daily doses in patients with BRAFV600 mutation–positive melanoma. A favorable activity and tolerability profile was demonstrated at 150 mg BID. There was no improvement with TID dosing compared with BID dosing, based on FDG-PET and tumor response analyses in patients with melanoma.Conclusion: The RP2D of dabrafenib was determined to be 150 mg BID after considering multiple factors, including pharmacokinetics, tissue pharmacodynamics, FDG-PET pharmacodynamics, and the dose–response relationship. A maximum tolerated dose for dabrafenib was not determined. Clin Cancer Res; 20(17); 4449–58. ©2014 AACR.

Table S1. Treatment-related adverse events of {greater than or equal to} grade 2 reported in at least 5% of patients by dose (3); Table S2. Summary of plasma dabrafenib pharmacokinetic parameters after single-dose administration of dabrafenib gelatin capsules under fasted conditions (dose escalation: Part 1); Table S3. Summary of plasma dabrafenib pharmacokinetic parameters after repeated dose administration of dabrafenib gelatin capsules under fasting conditions on day 8 or day 15 (dose escalation: Part 1).

Purpose: Although durable responses can be achieved with tyrosine kinase inhibitors such as imatinib in melanomas harboring KIT mutations, the efficacy of alternative inhibitors after progression to imatinib and the activity of these agents on brain metastases are unknown.Experimental Design: We conducted a phase II study of nilotinib 400 mg twice a day in two cohorts of patients with melanomas harboring KIT mutations or amplification: (A) those refractory or intolerant to a prior KIT inhibitor; and (B) those with brain metastases. The primary endpoint was 4-month disease control rate. Secondary endpoints included response rate, time-to-progression (TTP), and overall survival (OS). A Simon two-stage and a single-stage design was planned to assess for the primary endpoint in cohorts A and B, respectively.Results: Twenty patients were enrolled and 19 treated (11 in cohort A; 8 in cohort B). Three patients on cohort A [27%; 95% confidence interval (CI), 8%–56%] and 1 on cohort B (12.5%; 90% CI, 0.6%–47%) achieved the primary endpoint. Two partial responses were observed in cohort A (18.2%; 90% CI, 3%–47%); none were observed in cohort B. The median TTP and OS was 3.3 (90% CI, 2.1–3.9 months) and 9.1 months (90% CI, 4.3–14.2 months), respectively, in all treated patients.Conclusions: Nilotinib may achieve disease control in patients with melanoma harboring KIT alterations and whose disease progressed after imatinib therapy. The efficacy of this agent in KIT-altered melanoma with brain metastasis is limited. Clin Cancer Res; 21(10); 2289–96. ©2015 AACR.

Purpose: Standard-dose pembrolizumab plus alternative-dose ipilimumab (1 mg/kg Q3W for 4 doses) were tolerable and had robust antitumor activity in advanced melanoma in cohort B of the phase 1 KEYNOTE-029 study. Cohort C evaluated standard-dose pembrolizumab with two other alternative ipilimumab regimens. Patients and Methods: Patients with treatment-naive unresectable stage III/IV melanoma were randomly assigned 1:1 to pembrolizumab 200 mg Q3W for ≤24 months plus ipilimumab 50 mg Q6W for 4 doses (PEM200+IPI50), or the same pembrolizumab regimen plus ipilimumab 100 mg Q12W for 4 doses (PEM200+IPI100). Primary end points were incidence of grade 3–5 treatment-related adverse events (TRAE) and objective response rate (ORR) per RECIST v1.1 by independent central review. Per protocol-defined thresholds, grade 3–5 TRAE incidence ≤26% indicated meaningful toxicity reduction and ORR ≥48% indicated no decrease in efficacy versus data reported for other PD-1 inhibitor/ipilimumab combinations. Results: Median follow-up on February 18, 2019, was 16.3 months in PEM200+IPI50 (N = 51) and 16.4 months in PEM200+IPI100 (N = 51). Grade 3–5 TRAEs occurred in 12 (24%) patients in PEM200+IPI50 and 20 (39%) in PEM200+IPI100. One patient in PEM200+IPI50 died from treatment-related autoimmune myocarditis. Immune-mediated AEs or infusion reactions occurred in 21 (42%) patients in PEM200+IPI50 and 28 (55%) in PEM200+IPI100. ORR was 55% in PEM200+IPI50; 61% in PEM200+IPI100. Conclusions: Pembrolizumab 200 mg Q3W plus ipilimumab 50 mg Q6W or 100 mg Q12W demonstrated antitumor activity above the predefined threshold; pembrolizumab plus ipilimumab 50 mg Q6W had lower incidence of grade 3–5 TRAEs than the predefined threshold, suggesting a reduction in toxicity. See related commentary by Jameson-Lee and Luke, p. 5153

Background CAPRA (NCT02565992) evaluated Coxsackievirus A21 (V937) + pembrolizumab for metastatic/unresectable stage IIIB–IV melanoma. Methods Patients received intratumoral V937 on days 1, 3, 5, and 8 (then every 3 weeks [Q3W]) and intravenous pembrolizumab 2 mg/kg Q3W from day 8. Primary endpoint was safety. Results Median time from first dose to data cutoff was 32.0 months. No dose-limiting toxicities occurred; 14% (5/36) of patients experienced grade 3‒5 treatment-related adverse events. Objective response rate was 47% (complete response, 22%). Among 17 responders, 14 (82%) had responses ≥ 6 months. Among 8 patients previously treated with immunotherapy, 3 responded (1 complete, 2 partial). Responses were associated with increased serum CXCL10 and CCL22, suggesting viral replication contributes to antitumor immunity. For responders versus nonresponders, there was no difference in baseline tumor PD-L1 expression, ICAM1 expression, or CD3+ infiltrates. Surprisingly, the baseline cell density of CD3+CD8− T cells in the tumor microenvironment was significantly lower in responders compared with nonresponders (P = 0.0179). Conclusions These findings suggest responses to this combination may be seen even in patients without a typical “immune-active” microenvironment. Trial registration number NCT02565992.

BRAF mutations are relatively common in many cancers, particularly melanoma, colorectal cancer, and thyroid cancer and to a lesser extent in lung cancer. These mutations can be targeted by BRAF and MEK inhibitors, which exhibit good clinical activity. There are conflicting reports of the various relative rates of BRAF Class I mutations (V600 locus), defined as those that exhibit extremely strong kinase activity by stimulating monomeric activation of BRAF, Class II, define as non-V600 mutations that activate BRAF to signal as a RAS-independent dimer, and Class III mutations, defined as “kinase-dead” with low kinase activity as compared to wild type BRAF. Prospective studies have largely focused on patients with tumors harboring Class I BRAF mutations (limited to the V600 locus) where response rates up to 70% with BRAF plus MEK inhibition have been demonstrated. We report on the relative prevalence of various types of BRAF mutations across human cancers in a cohort of 114,662 patients that received comprehensive genomic profiling using next-generation sequencing. Of these patients, 4517 (3.9%) a pathogenic or presumed pathogenic BRAF mutation (3.9%). Of these, 1271 were seen in melanoma, representing 39.7% of all melanomas sequenced, representing the highest rate in all tumors. Class I (V600) mutations were seen overall in 2841 patients (62.1% of BRAF mutations, 2.4% of total cancers). Class II mutations were seen in 746 tumors (16.5% of BRAF mutant, 0.7% of total), and Class III mutations were seen in 801 tumors (17.7% of BRAF, 0.7% of total). Knowledge of the relative prevalence of these types of mutations can aid in the development of agents that might better address non-V600 mutations in cancer. Impact statement These data represent the largest aggregation of BRAF mutations within a single clinical database to our knowledge. The relative proportions of both BRAF V600 mutations and non-V600 mutations are informative in all cancers and by malignancy, and can serve as a definitive gold-standard for BRAF mutation cancer incidence by malignancy. The rate of BRAF mutation in human cancer in a real-world large database is lower than previously reported likely representing testing more broadly across tumor types. The relative percentages of Class II and Class III BRAF mutations are higher than previously reported, representing almost 35% of BRAF mutations in cancer. These findings provide support for the development of effective treatments for non-V600 BRAF mutations in cancer.

Background Brain metastases are a significant cause of mortality and morbidity for patients with melanoma. We hypothesize that the development of brain metastases may be explained by molecular heterogeneity between primary cutaneous melanoma (PCM) or extracranial (ECM) and brain (MBM) melanoma metastases. Materials and methods We compared next-generation sequencing, tumor mutational burden (TMB), and immunohistochemical staining for PD-L1 expression, among 132 MBM, 745 PCM, and 1190 ECM. Results The most common genetic alterations among MBM included: BRAF (52.4%), NRAS (26.6%), CDKN2A (23.3%), NF1 (18.9%), TP53 (18%), ARID2 (13.8%), SETD2 (11.9%), and PBRM1 (7.5%). Four genes were found with higher frequency among MBM compared to PCM or ECM: BRAF (52.4% v 40.4% v 40.9%), SETD2 (11.9% v 1.9% v 3.9%), PBRM1 (7.5% v 1.6% v 2.6%), and DICER1 (4.4% v 0.6% v 0.4%). MBM showed higher TMB (p = .04) and higher PD-L1 expression (p = .002), compared to PCM. PD-L1 expression was slightly higher among MBM compared to ECM (p = .042), but there was no difference between TMB (p = .21). Conclusions Our findings suggest a unique molecular profile for MBM, including higher rates of BRAF mutations, higher TMB and higher PD-L1 expression, and also implicate chromatin remodeling in the pathogenesis of MBM.

Purpose To determine the recommended phase 2 dose of RRx-001, a radiosensitizer with vascular normalizing properties, when used with whole-brain radiation therapy (WBRT) for brain metastases and to assess whether quantitative changes in perfusion magnetic resonance imaging (MRI) after RRx-001 correlate with response. Methods and Materials Five centers participated in this phase 1/2 trial of RRx-001 given once pre-WBRT and then twice weekly during WBRT. Four dose levels were planned (5 mg/m2, 8.4 mg/m2, 16.5 mg/m2, 27.5 mg/m2). Dose escalation was managed by the time-to-event continual reassessment method algorithm. Linear mixed models were used to correlate change in 24-hour T1, Ktrans (capillary permeability), and fractional plasma volume with change in tumor volume. Results Between 2015 and 2017, 31 patients were enrolled. Two patients dropped out before any therapy. Median age was 60 years (range, 30-76), and 12 were male. The most common tumor types were melanoma (59%) and non-small cell lung cancer (18%). No dose limiting toxicities were observed. The most common severe adverse event was grade 3 asthenia (6.9%, 2 of 29). The median intracranial response rate was 46% (95% confidence interval, 24-68) and median overall survival was 5.2 months (95% confidence interval, 4.5-9.4). No neurologic deaths occurred. Among 10 patients undergoing dynamic contrast-enhanced MRI, a reduction in Vp 24 hours after RRx-001 was associated with reduced tumor volume at 1 and 4 months (P ≤ .01). Conclusions The addition of RRx-001 to WBRT is well tolerated with favorable intracranial response rates. Because activity was observed across all dose levels, the recommended phase 2 dose is 10 mg twice weekly. A reduction in fractional plasma volume on dynamic contrast-enhanced MRI 24 hours after RRx-001 suggests antiangiogenic activity associated with longer-term tumor response.

Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is characterized by respiratory distress, multiorgan dysfunction, and, in some cases, death. The pathological mechanisms underlying COVID-19 respiratory distress and the interplay with aggravating risk factors have not been fully defined. Lung autopsy samples from 18 patients with fatal COVID-19, with symptom onset-to-death times ranging from 3 to 47 days, and antemortem plasma samples from 6 of these cases were evaluated using deep sequencing of SARS-CoV-2 RNA, multiplex plasma protein measurements, and pulmonary gene expression and imaging analyses. Prominent histopathological features in this case series included progressive diffuse alveolar damage with excessive thrombosis and late-onset pulmonary tissue and vascular remodeling. Acute damage at the alveolar-capillary barrier was characterized by the loss of surfactant protein expression with injury to alveolar epithelial cells, endothelial cells, respiratory epithelial basal cells, and defective tissue repair processes. Other key findings included impaired clot fibrinolysis with increased concentrations of plasma and lung plasminogen activator inhibitor-1 and modulation of cellular senescence markers, including p21 and sirtuin-1, in both lung epithelial and endothelial cells. Together, these findings further define the molecular pathological features underlying the pulmonary response to SARS-CoV-2 infection and provide important insights into signaling pathways that may be amenable to therapeutic intervention.

Background Spherical nucleic acids (SNAs) are nanostructures consisting of radially oriented, densely packed oligonucleotides arranged in a spherical 3D architecture. SNAs have different properties than linear oligonucleotides, including increased cellular uptake, which may enhance efficacy. Cavrotolimod (AST-008) is an SNA toll-like receptor 9 (TLR9) agonist designed to robustly activate innate and adaptive immune responses. Cavrotolimod is in development for the treatment of advanced solid tumors in combination with PD-1 blockade. Prior studies demonstrated that cavrotolimod, alone and in combination with PD-1 blockade, increased circulating levels of Th1-type cytokines and activated peripheral T cells and NK cells. Methods AST-008-102 is an ongoing Phase 1b/2 study (NCT03684785). The Phase 1b dose escalation stage examined intratumoral (IT) cavrotolimod at doses of 2, 4, 8, 16, and 32 mg in combination with pembrolizumab in patients with advanced solid tumors. Cavrotolimod was dosed once weekly for 8 weeks and once every 3 weeks thereafter. The Phase 2 dose expansion stage is examining cavrotolimod 32 mg IT in combination with IV pembrolizumab for the treatment of advanced Merkel cell carcinoma (MCC) and in combination with IV cemiplimab for the treatment of advanced cutaneous squamous cell carcinoma (CSCC). Both cohorts are enrolling patients with documented progression of disease on PD-(L)1 blockade. This analysis provides interim results of the Phase 1b stage. Results In the Phase 1b stage, 20 patients were enrolled across all planned dose levels. No dose-limiting toxicities, grade (G)4 toxicities, or treatment-related serious adverse events (AEs) were observed. The most common AEs were injection site reactions (ISRs) and flu-like symptoms. All treatment-related AEs were Conclusions IT administration of cavrotolimod appears to be safe and well tolerated in combination with pembrolizumab. Durable responses have occurred in patients previously experiencing progressive disease on PD-1 blockade. Trial Registration NCT03684785 Ethics Approval The study was approved by Institutional Review Boards of Dana-Farber Cancer Institute (IRB #18-584), John Wayne Cancer Institute (WIRB #20183064), University of Miami (IRB #20180957), University of Iowa (IRB #201810763), University of Cincinnati (WIRB #20183064), University of Washington (WIRB #20183064), MSKCC (IRB #20-174), UC San Francisco (WIRB #20183064), U Colorado (WIRB #20183064), Northwestern (IRB #STU00211083), U Arizona (WIRB #20183064), UC Irvine (WIRB #20183064), U Pitt (WIRB #20183064), and Washington University (WIRB #20183064).

Background Immune checkpoint therapies targeting CTLA-4, alone, or in combination with anti-PD-1 have shown durable responses in cancer patients. However, responses are limited to a small subset of patients in the most common immunogenic cancers. Here we describe, a novel anti-CTLA-4 antibody, AGEN1181, with enhanced FcyR-dependent functionality that harnesses a novel mechanism of action to promote superior T cell activation and anti-cancer immunity. Concordant with preclinical findings, we report preliminary safety, pharmacodynamic and efficacy data from a phase 1 study of AGEN1181 (NCT03860272), alone or in combination with balstilimab (anti-PD-1 antibody) in a range of immunogenic and non-immunogenic tumors. Methods The functional activity of AGEN1181 or AGEN1181-like mouse surrogate were assessed in primary cell-based assays or in PD-1 refractory syngeneic tumor-bearing mouse models (B16F10 or KPC pancreatic tumor). Efficacy was evaluated as monotherapy, or in combination with anti-PD-1, focal radiation or chemotherapy. In an ongoing phase I study, AGEN1181 is administered intravenously once every 3- or 6-weeks as monotherapy (0.1–4 mg/kg), or every 6-weeks (1–4 mg/kg) in combination with balstilimab (3 mg/kg) dosed every 2 weeks. Dose-limiting toxicities were evaluated in the first 28 days of treatment. Neoantigen burden was assessed from pre-treatment tumor biopsy, as available, by next-generation sequencing. Fcγ receptor genotyping was assessed by real-time PCR. Immunophenotyping of peripheral blood mononuclear cells collected pre- and post-treatment were analyzed by flow cytometry. Results Preclinically, AGEN1181 demonstrated superior T cell activation than a standard IgG1 anti-CTLA-4 analogue in donors expressing either the low or high affinity FcγRIIIA. In poorly immunogenic tumor-bearing mouse models, AGEN1181-like surrogate demonstrated robust tumor control in combination with anti-PD-1 and focal radiation or chemotherapy. As of August 25th, 2020, we observed a clinical benefit rate of 63–53% at 6 and 12 weeks respectively among evaluable treated patients. We observed two durable responses in patients with endometrial cancer that were BRCA-, microsatellite stable and PD-L1 negative. These patients progressed on prior PD-1 therapy or chemoradiation respectively. Notably, responders expressed either the low or high affinity FcγRIIIA. AGEN1181 showed potent dose-dependent increases in peripheral CD4+Ki67+, CD4+ICOS+ and CD4+HLA-DR+ T-cells. Treatment was well tolerated through the highest dose tested. Grade 3 or greater immune-related adverse events occurred in 28.5% patients and were consistent with CTLA-4 therapies. Conclusions AGEN1181 is designed to expand the benefit of anti-CTLA-4 therapy to a broader patient population. AGEN1181, alone or in combination with balstilimab, demonstrates clinical activity in heavily pretreated patients. Trial Registration NCT03860272

Background Basal cell carcinoma (BCC) is considered an immunogenic tumor based on the high tumor mutational burden (TMB), increased incidence in immunocompromised patients, and responsiveness to imiquimod, a toll-like receptor agonist therapy. However, anti-PD-1 immunotherapy response rates in patients with advanced BCC appear less than that seen with other advanced cutaneous malignancies. Molecular profiles of BCC tumors were analyzed to determine immune phenotypes and resistance mechanisms in comparison to other anti-PD-1 therapy responsive cutaneous malignancies. Methods Next generation sequencing on DNA (NGS; NextSeq and Novaseq), PD-L1 immunohistochemistry (SP-142 and 28–8 antibody clones, cutoff >5% tumor staining) and mRNA gene expression level (Whole Transcriptome Sequencing, NovaSeq) data from BCC (N=69), melanoma (N=914), and cutaneous squamous cell carcinoma (SCC) tumors (N=165) at Caris Life Sciences (Phoenix, AZ) were analyzed. Tumor mutational burden (TMB) was calculated by counting all non-synonymous missense mutations that had not been previously described as germline alterations. Microenvironment cell population counter1 was used to estimate cell population abundance in the TME. Gene set enrichment analysis (GSEA) was performed on transcriptomes.2 Statistical significance was set at P value or false discovery rate (FDR) Results Of the 69 BCC tumors with NGS data, the most frequent mutations were in PTCH1 (82%), P53 (73%) and ARID1A (42%); additional relevant mutations included SMO (18%), JAK1 (9%), PI3KCA (6%), APC (4%), and CTNNB1 (3%). TMB was significantly greater in BCC compared to melanoma (median 30.5 vs 12 mut/Mb, P Conclusions While BCC tumors demonstrated a high TMB, a markedly lower level of adaptive anti-tumor immunity in comparison to other cutaneous malignancies was observed. T-cell exclusion mechanisms mediated through CAFs and desmoplasia, with upregulation of TGF-beta and angiogenic signaling, may play a role. Further investigation into abrogation of these mechanisms is warranted to develop improved anti-PD-1 based therapies for BCC. References Becht E, Giraldo NA, Lacroix L, Buttard B, Elarouci N, Petitprez F, Selves J, Laurent-Puig P, Sautes-Fridman C, Fridman WH, de Reynies A. Estimating the population abundance of tissue-infiltrating immune and stromal cell populations using gene expression. Genome Biol 2016; 17(1):218. Subramanian A, Tamayo P, Mootha VK, Mukherjee S, Ebert BL, Gillette MA, Paulovich A, Pomeroy SL, Golub TR, Lander ES, Mesirov JP. Gene set enrichment analysis: a knowledge-based approach for interpreting genome-wide expression profiles. Proc Natl Acad Sci U S A 2005;102(43):15545–50.

Serum lactate dehydrogenase (LDH) is a standard prognostic biomarker for stage IV melanoma patients. Often, LDH levels do not provide real-time information about the metastatic melanoma patients&rsquo, disease status and treatment response. Therefore, there is a need to find reliable blood biomarkers for improved monitoring of metastatic melanoma patients who are undergoing checkpoint inhibitor immunotherapy (CII). The objective in this prospective pilot study was to discover circulating cell-free microRNA (cfmiR) signatures in the plasma that could assess melanoma patients&rsquo, responses during CII. The cfmiRs were evaluated by the next-generation sequencing (NGS) HTG EdgeSeq microRNA (miR) Whole Transcriptome Assay (WTA, 2083 miRs) in 158 plasma samples obtained before and during the course of CII from 47 AJCC stage III/IV melanoma patients&rsquo, and 73 normal donors&rsquo, plasma samples. Initially, cfmiR profiles for pre- and post-treatment plasma samples of stage IV non-responder melanoma patients were compared to normal donors&rsquo, plasma samples. Using machine learning, we identified a 9 cfmiR signature that was associated with stage IV melanoma patients being non-responsive to CII. These cfmiRs were compared in pre- and post-treatment plasma samples from stage IV melanoma patients that showed good responses. Circulating miR-4649-3p, miR-615-3p, and miR-1234-3p demonstrated potential prognostic utility in assessing CII responses. Compared to LDH levels during CII, circulating miR-615-3p levels were consistently more efficient in detecting melanoma patients undergoing CII who developed progressive disease. By combining stage III/IV patients, 92 and 17 differentially expressed cfmiRs were identified in pre-treatment plasma samples from responder and non-responder patients, respectively. In conclusion, this pilot study demonstrated cfmiRs that identified treatment responses and could allow for real-time monitoring of patients receiving CII.

IMPORTANCE: The optimal sequencing of immune checkpoint inhibitors and targeted therapy for BRAF V600E/K-mutant melanoma is not well established. OBJECTIVE: To assess the association of BRAF wild-type (WT) or BRAF V600E/K-mutant status and BRAF inhibitor (BRAFi) with or without MEK inhibitor (MEKi) therapy with response to pembrolizumab. DESIGN, SETTING, AND PARTICIPANTS: This study is a post hoc subgroup analysis of pooled data from 3 multinational, multisite studies: KEYNOTE-001 (data cutoff September 1, 2017), KEYNOTE-002 (data cutoff May 30, 2018), and KEYNOTE-006 (data cutoff December 4, 2017). Patients included in this analysis were adults with advanced melanoma and known BRAF V600E/K tumor status who had received pembrolizumab. INTERVENTIONS: Patients received pembrolizumab in dosages of 2 mg/kg every 3 weeks, 10 mg/kg every 2 weeks, or 10 mg/kg every 3 weeks. MAIN OUTCOMES AND MEASURES: End points were objective response rate (ORR) and progression-free survival (PFS) assessed by Response Evaluation Criteria in Solid Tumors, version 1.1, and overall survival (OS). Objective response rates, 4-year PFS, and OS rates were compared in the following patient subgroups: BRAF WT vs BRAF V600E/K-mutant melanoma and BRAF V600E/K-mutant melanoma with vs without previous treatment with BRAFi with or without MEKi therapy. RESULTS: The overall study population (N = 1558) included 944 men (60.6%) and 614 women (39.4%). The mean (SD) age was 60.0 years (14.0). The ORR was 38.3% (596/1558), 4-year PFS rate was 22.0%, and 4-year OS rate was 36.9%. For patients with BRAF WT (n = 1124) and BRAF V600E/K-mutant melanoma (n = 434), ORR was 39.8% (n = 447) and 34.3% (n = 149), 4-year PFS rate was 22.9% and 19.8%, and 4-year OS rate was 37.5% and 35.1%, respectively. Patients with BRAF V600E/K-mutant melanoma who had (n = 271) vs had not (n = 163) previously received BRAFi with or without MEKi therapy had baseline characteristics with worse prognosis; ORR was 28.4% (n = 77) and 44.2% (n = 72), 4-year PFS rate was 15.2% and 27.8%, and 4-year OS rate was 26.9% and 49.3%, respectively. CONCLUSIONS AND RELEVANCE: Results of this subgroup analysis support the use of pembrolizumab for treatment of advanced melanoma regardless of BRAF V600E/K mutation status or receipt of prior BRAFi with or without MEKi therapy.

Primary cutaneous melanoma frequently metastasizes to distant organs including the brain. Identification of cell-free microRNAs (cfmiRs) found in the blood can be used as potential body fluid biomarkers for detecting and monitoring patients with melanoma brain metastasis (MBM). In this pilot study, we initially aimed to identify cfmiRs in the blood of MBM patients. Normal donors plasma (healthy, n = 48) and pre-operative MBM patients&rsquo, plasma samples (n = 36) were compared for differences in &gt, 2000 microRNAs (miRs) using a next generation sequencing (NGS) probe-based assay. A 74 cfmiR signature was identified in an initial cohort of MBM plasma samples and then verified in a second cohort of MBM plasma samples (n = 24). Of these, only 58 cfmiRs were also detected in MBM tissues (n = 24). CfmiR signatures were also found in patients who have lung and breast cancer brain metastasis (n = 13) and glioblastomas (n = 36) compared to MBM plasma samples. The 74 cfmiR signature and the latter cfmiR signatures were then compared. We found a 6 cfmiR signature that was commonly upregulated in MBM plasma samples in all of the comparisons, and a 29 cfmiR signature that distinguishes MBM patients from normal donors&rsquo, samples. In addition, we assessed for cfmiRs in plasma (n = 20) and urine (n = 14) samples collected from metastatic melanoma patients receiving checkpoint inhibitor immunotherapy (CII). Pre- and post-treatment samples showed consistent changes in cfmiRs. Analysis of pre- and post-treatment plasma samples showed 8 differentially expressed (DE) cfmiRs that overlapped with the 35 cfmiR signature found in MBM patients. In paired pre-treatment plasma and urine samples receiving CII 8 cfmiRs overlapped. This study identified specific cfmiRs in MBM plasma samples that may potentially allow for assessment of melanoma patients developing MBM. The cfmiR signatures identified in both blood and urine may have potential utility to assess CII responses after further validation.

Background: CPI monotherapy provides substantial clinical benefit to patients (pts) in multiple cancers, yet response rates are limited (˜15-30%) and fails to benefit the majority. In these pts there is limited or no ongoing T cell-based immune response. Imprime PGG (Imprime), a novel beta glucan derived from Saccharomyces, may expand the clinical benefit of CPI therapy by stimulating an anti-cancer immune response. Acting as a pathogen-associated molecularpattern (PAMP), Imprime enlists innate immune functions including cytotoxic effector mechanisms, reversal of immunosuppression and cross-talk with the adaptive immune system.Imprime-mediated innate immune activation requires formation of an immune complex with naturally-occurring anti-beta glucan antibodies (ABA); sufficient ABA levels is required for complex formation. Imprime is now being studied in combination with pembrolizumab (KEYTRUDA®,Pembro), a humanized mAb against PD-1 which has been previously studied in TNBC pts. Methods: In this study of patients who previously failed chemotherapy for metastatic TNBC, Imprime is being used in combination with Pembro in a Simon 2 stage design. Asample size of 12 evaluable pts in Stage 1 was planned.Evaluable pts received at least one dose of study treatment (tx), had measurable disease at baseline per RECIST v1.1, had at least one post-baseline scan or discontinued tx as a result of progressive disease, death, or a tx-related adverse event before the first post-baseline scan.Pts received Imprime (4 mg/kg IV days 1, 8, 15 of each 3-week cycle) + Pembro 200 mg on D1 of each cycle. Criteria to advance to Stage 2 were ≤4 grade 3/4 AEs during the first tx cycle (other than infusion reactions) and ≥1 objective response. Study primary endpoints are ORR and safety; secondary endpoints are TTR, CRR, DoR, PFS, and OS. Exploratory endpoints include ORR and PFS per irRECIST. Biopsies and blood samples are being collected to assess tx impact on immune activating events at the tumor site and in the periphery. Results: A review of efficacy and safety data was conducted at the end of Stage 1. Thirteen pts (12 evaluable) were enrolled into Stage 1. Safety review noted 2 grade 3 adverse events that met protocol definition of Stage 1 events (1 pt: cellulitis and 1 pt: pleural infusion; both unrelated to treatment). Two events lead to 2 pts discontinuing treatment (infusion reaction and pancreatitis) and only 1 autoimmune event was observed (pancreatitis). Observed efficacy responses in the evaluable pts included 1 complete response (CR; ongoing) and 2 partial responses (PR; ongoing). Secondary efficacy endpoints have not been assessed. Early translational results support proposed MOA and analysis of Stage 1 translational data is ongoing. Conclusion: The use of Imprime with Pembro was well tolerated and met both safety and efficacy requirements to move forward with Stage 2 of the study. No significant safety concerns were identified in Stage 1. Further investigation is thus warranted and enrollment into Stage 2 is ongoing. Updated data will be presented. Citation Format: O'Day S, Borges V, Chmielowski B, Rao R, Abu-Khalaf M, Stopeck A, Lowe J, Mattson P, Breuer K, Gargano M, Bose N, Uhlik M, Graff J, Chisamore M, Cox J, Osterwalder B. Imprime PGG, a novel innate immune modulator, combined with pembrolizumab in a phase 2 multicenter, open label study in chemotherapy-resistant metastatic triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-09-08.

BackgroundAGEN1181 is a novel anti-CTLA-4 antibody with enhanced FcyR-dependent functionality, engineered to bind high and low binding alleles of FcyRIIIA, promoting superior T cell priming, memory responses, and depletion of intratumoral T regulatory cells. Further, AGEN1181 avoids complement recruitment, predictive of better tolerability. Here we report initial safety and efficacy findings from a phase I/Ib study of AGEN1181 as monotherapy and in combination with balstilimab (BAL; anti-PD-1).MethodsEligible patients (pts) had advanced solid tumors refractory to standard therapies. AGEN1181 was dosed Q3W (0.1–3 mg/kg) or Q6W (1–2 mg/kg) as monotherapy, or Q6W (0.1–2 mg/kg) in combination with BAL Q2W (3 mg/kg).ResultsAs of July 16th 2021, 102 pts received AGEN1181 (43 monotherapy, 59 combination). Median age, 63 years (29–83); 50.5% with ≥3 prior lines of therapy. MTD not yet reached with AGEN1181 dosing up to 3 mg/kg Q3W as monotherapy and 2 mg/kg in combination with BAL. The most common treatment-related adverse events (TRAEs) of any grade were fatigue (34.3%), diarrhea (32.4%), and nausea (19.6%) with grade ≥3 events in 21.6% (diarrhea/colitis, 11.8%, fatigue, 2.9%). Notably, no immune-related hypophysitis or pneumonitis has been observed. Discontinuation from AGEN1181 due to TRAEs occurred in 15% of pts. Grade 5 TRAEs occurred in two pts (colitis [chronic], intestinal perforation). The disease control rate in evaluable pts (completed ≥1 on-treatment scan) defined as best overall response of CR, PR, or SD ≥6 weeks was 48.1% for AGEN1181 monotherapy ≥1 mg/kg (1 CR, 3 PR, 9 SD) and 70% for combination (3 PR, 6 unconfirmed PR [uPR], 19 SD). Monotherapy responders include individual pts with MSS endometrial cancer (CR), PD-1-relapsed/refractory cervical cancer (PR), PD-1-relapsed/refractory melanoma (PR), and pancreatic cancer (PR). Enrollment is continuing in several disease expansion cohorts with combination therapy. For MSS CRC, 2 PR, 2 uPR, and 7 SD have been seen in 17 evaluable ≥1 mg/kg patients to date. In the ovarian cohort (n=6), 2 PRs and 3 SD are noted. Additional combination responders include one PR and uPR in MSS endometrial cancer, two uPRs in visceral angiosarcoma (uPRs) and one uPR in PD-1-relapsed/refractory NSCLC (uPR); the majority of the responses are recent and ongoing.ConclusionsAGEN1181 alone and in combination with BAL demonstrates favorable tolerability and compelling clinical activity, notably in poorly immunogenic tumor types and PD-1-refractory pts. These results underscore the significant potential of AGEN1181 to expand benefit of anti-CTLA-4 therapy to a broader patient population.Trial RegistrationNCT03860272Ethics ApprovalThe study obtained ethics approval at each participating center (UT Health Sciences Center at San Antonio, University of Colorado Cancer Center, St John’s Cancer Institute, and HonorHealth under WIRB Study number 1256391; USC Norris Comprehensive Cancer Center, Beth Israel Deaconess Medical Center, and MD Anderson Cancer Center, approval numbers HS19-00277, 19–132, and 140346, respectively). All patients provided written informed consent in accordance with federal, local, and institutional guidelines.

BACKGROUNDBlood molecular profiling of circulating tumor cells (CTCs) can enable monitoring of patients with metastatic melanoma during checkpoint inhibitor immunotherapy (CII) and in combination with targeted therapies. We developed a microfluidics-based CTC platform to explore CTC profiling utility in CII-treated patients with melanoma using a melanoma messenger RNA (mRNA)/DNA biomarker panel.METHODSBlood samples (n = 213) were collected prospectively from 75 American Joint Committee on Cancer-staged III/IV melanoma patients during CII treatment and those enriched for CTCs. CTC profiling was performed using 5 known melanoma mRNA biomarkers and BRAF V600E DNA mutation. CTC biomarker status associations with clinical outcomes were assessed.RESULTSCTCs were detected in 88% of blood samples from patients with melanoma. CTC-derived biomarkers and clinical variables analyzed using classification and regression tree analysis revealed that a combination of lactate dehydrogenase, CTC-mRNA biomarkers, and tumor BRAF–mutation status was indicative of clinical outcomes for patients with stage IV melanoma (n = 52). The panel stratified low-risk and high-risk patients, whereby the latter had poor disease-free (P = 0.03) and overall survival (P = 0.02). Incorporation of a DNA biomarker with mRNA profiling increased overall CTC-detection capability by 57% compared to mRNA profiling only. RNA sequencing of isolated CTCs identified significant catenin beta 1 (CTNNB1) overexpression (P CONCLUSIONSCTC-derived mRNA/DNA biomarkers have utility for monitoring CII, targeted, and combinatorial therapies in metastatic melanoma patients.

Background: Coxsackievirus A21 (V937) is an RNA oncolytic virus targeting ICAM-1 receptors. Pharmacodynamic effects of oncolytic viruses in the tumor microenvironment (TME), including increased CD8+ T cells and PD-L1 expression, support their use in combination with checkpoint inhibitors. We present updated clinical and correlative data from the multicenter phase 1b CAPRA study (NCT02565992) of V937 + pembro in pts with advanced melanoma. Methods: Eligible pts had metastatic/unresectable stage IIIB-IV melanoma and ≥1 cutaneous/subcutaneous tumor or lymph node amenable to V937 intratumoral injection. Pts received V937 on days 1, 3, 5, and 8; then Q3W for up to 19 injections (maximum dose, 3 × 108 50% TCID50). Pts received IV pembro 2 mg/kg Q3W on day 8, continuing for up to 2 y. Primary endpoints were incidence of AEs, serious AEs (SAEs), and dose-limiting toxicities (DLTs). Secondary endpoints were ORR, duration of response (DOR), PFS, and OS. Biomarkers were an exploratory endpoint. Results: 36 pts were enrolled (mean age, 68.5 y; 75% male; 22% had prior immunotherapy). As of 4 Nov 2019, median (range) time from first dose to data cutoff was 32.0 (10.7−45.3) mo. No DLTs occurred. Grade 3-5 treatment-related AEs occurred in 5 (14%) pts. 3 (8%) pts had treatment-related SAEs (autoimmune encephalitis and septic shock in 1 pt, keratoacanthoma, autoimmune hepatitis); 1 died from septic shock. Efficacy results included ORR of 47% (CR, 22%; PR, 25%; Table 1). In comparing responders vs nonresponders, baseline tumor samples showed no difference in PD-L1 expression and lower CD3+CD8- infiltrate in responders. Conclusions: V937 + pembro had manageable safety and promising efficacy in pts with advanced melanoma. Response was not associated with an inflamed TME at baseline, indicating that V937 may induce an immune responsive TME. The combination is being studied in the neoadjuvant setting in pts with stage III melanoma (KEYMAKER-U02). Table 1.Efficacy OutcomesV937 + Pembro (N = 36)ORR,a % (95% CI)b47 (30-65)- CR22 (10-39)- PR25 (12-42)DOR,c median (range), moNR (1.4+ to 22.0+)PFS,c,d median (95% CI), mo11.9 (3.4-NR)12-mo PFS,c % (95% CI)45 (28-60)OS,c median (95% CI), mo30.9 (20.3-40.5)12-mo OS,c % (95% CI)85 (68-94)+ indicates no PD by the time of last disease assessment. NR, not reached.aBest overall response with confirmation based on investigator assessment per immune-related response criteria; imaging was performed Q6W.bBased on the exact method for binomial data.cKaplan-Meier estimate.dBased on investigator assessment per immune-related response criteria. Citation Format: Ann W. Silk, Steven J. O'Day, Howard L. Kaufman, Jennifer Bryan, Jacqueline T. Norrell, Casey Imbergamo, Daniella Portal, Edwin Zambrano-Acosta, Marisa Palmeri, Seymour Fein, Cai Wu, Leslie Guerreiro, Daniel Medina, Praveen K. Bommareddy, Andrew Zloza, Bernard A. Fox, Carmen Ballesteros-Merino, Darren Shafren, Mark Grose, Joshua A. Vieth, Janice M. Mehnert. Intratumoral oncolytic virus V937 in combination with pembrolizumab (pembro) in patients (pts) with advanced melanoma: Updated results from the phase 1b CAPRA study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT139.

Nivolumab and ipilimumab +/- UV1 vaccine as 1st line treatment in patients with malignant melanoma (INITIUM-trial)Malignant melanomas (MM) are tumors originating from the melanocytes in the skin or mucosal surfaces. Even if the prognosis has improved considerably with the introduction of checkpoint inhibitors (CPIs) and BRAF/MEK inhibitors, half of the patients with metastatic MM dies within 5 years. Patients indicated for CPI as first line treatment will either receive a PD-1 antibody as monotherapy or a combination of CTLA-4 and PD-1 targeting antibodies. Patients are selected for monotherapy or combination therapy based on tumor staging, clinical- and biochemical status. The combination treatment has shown improved overall survival as compared to monotherapy, but also increased toxicity. The UV1 vaccine comprises 3 long peptides covering the active site of the tumor-associated antigen telomerase. Through UV1 vaccinations, patients induce telomerase-specific T cells with the potential of providing the necessary inflammatory tumor microenvironment for optimal immune-mediated tumor control. The UV1 vaccine is shown to induce immune responses in HLA-unselected patients across 3 completed phase I trials, covering MM, NSCLC, and prostate cancer. Accumulating evidence suggests that CPI efficacy is reliant on spontaneous anti-tumor immune responses. UV1 vaccination thus serves to increase CPI efficacy by providing the necessary anti-tumor immune responses, while the CPIs may reciprocally provide increased expansion and effector capacity of vaccine-induced T cells by blocking CTLA-4 and PD-l, respectively. The combination proposed in this trial may therefore lead to synergistic immunological activity translating to improved clinical outcome for MM patients.The INITIUM study (EudraCT no: 2019-002026-75) is an ongoing Ultimovacs sponsored, randomized, open-label, multi-center study comparing the efficacy and safety of nivolumab and ipilimumab with or without UV1 vaccination in 1st line metastatic MM patients.A total of 154 patients are randomized 1:1 to either arm A: 4 cycles of nivolumab (1 mg/kg q3w) + 4 cycles of ipilimumab (3 mg/kg q3w) + 8 injections with 300 μg UV1 and 75 μg GM-CSF as adjuvant (UV1 vaccination) during the first 13 weeks, or arm B: 4 cycles of nivolumab (1 mg/kg q3w) + 4 cycles of ipilimumab (3 mg/kg q3w). Patients randomized to treatment arm A will receive three UV1 vaccinations in week 1 and one in week 2, followed by 4 UV1 vaccinations throughout the following 11weeks, totaling to 8 UV1 vaccinations.Patients will continue with nivolumab maintenance treatment (480 mg q4w) according to the label. The primary endpoint is progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumours (RECIST 1.1) as determined by blinded independent central review (BICR).Samples of blood, feces, and tumor tissue are collected in a subset of patients for translational research purposes.Legal entity Ultimovacs ASA, Oslo, NorwayFundingUltimovacs ASA, Oslo, Norway Citation Format: Steven O'Day, Oliver Bechter, Paul Lorigan, Marta Nyakas. Nivolumab and ipilimumab +/- UV1 vaccine as 1st line treatment in patients with malignant melanoma (INITIUM-trial) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT231.

AGEN1181 is a novel, Fc-engineered monoclonal antibody that targets cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), with enhanced FcyR-dependent functionality designed to improve T cell priming and activation, deplete intratumoral regulatory T cells (Treg), and improve memory T cell response. AGEN1181 is currently undergoing Phase I clinical evaluation, both as a single agent and in combination with the anti-PD-1 antibody balstilimab, in patients with advanced solid tumors (NCT03860272). Encouraging signals of clinical benefit have emerged as part of this ongoing study, including complete and durable responses in patients that would traditionally be considered unresponsive to conventional CTLA-4/PD-1 therapy. Here we report on pharmacodynamic analyses associated with AGEN1181 exposure in patients on study in this trial. As monotherapy, AGEN1181 was administered on a once every 3 or once every 6 week cycle (doses escalated from 0.1 - 4 mg/kg). Alternatively, AGEN1181 was dosed once every six weeks in combination with balstilimab (3 mg/kg once every 2 weeks). Tumor mutational burden (TMB) and gene expression were assessed from pre-treatment and on-treatment biopsies by whole exome sequencing (WES) and RNASeq, respectively. Multiplex immunohistochemistry was used to assess Treg depletion and CD8 T-cell activation in response to AGEN1181. TCR repertoire was analyzed in PBMCs collected on-treatment with AGEN1181. FcγRIIIA genotyping was performed by real-time PCR. Immunophenotyping of peripheral blood mononuclear cells collected pre- and post-treatment were analyzed by flow cytometry. Consistent with its proposed mechanism of action, dose-dependent pharmacodynamic effects have been observed in patients while on-treatment with AGEN1181. Peripheral CD4+Ki67+, CD4+ICOS+ and CD4+HLA-DR+ T cells increased over baseline in response to monotherapy. This effect was further enhanced in subjects treated with AGEN1181 when given in combination with balstilimab. Responders expressed either the low affinity FcγRIIIA allele or were heterozygous - suggesting that AGEN1181 has the potential to expand clinical activity to patients with low affinity Fc binding, in contrast to conventional CTLA-4 inhibitors. Additionally, we show that AGEN1181 induced selective Treg depletion within the tumor microenvironment with concomitant increases in CD8 T cell infiltration. TCRSeq analysis demonstrated increased clonality and decreased downsampled diversity, providing further evidence that the Fc-enhanced activity of AGEN1181 can promote improved T cell priming and Treg depletion. In summary, the pharmacodynamic analyses presented here are consistent with the Fc-enhanced design of AGEN1181 and its potential to broaden the therapeutic reach of CTLA-4-based immunotherapy. Citation Format: Irina Shapiro, Min Lim, Simarjot Pabla, Steven J. O'Day, Anthony El-Khoueiry, Chethan Ramamurthy, Andrea J. Bullock, Michael S. Gordon, Jennifer Buell, Dhan Chand, Anna Wijatyk. Characterization of the pharmacodynamic activity of AGEN1181, an Fc-enhanced CTLA-4 antibody, alone and in combination with the PD-1 antibody balstilimab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1677.

2620 Background: UV1, a telomerase peptide-based vaccine, consists of 3 long peptides (15-30 aa) representing a 54 aa sequence in the catalytic unit of the reverse transcriptase subunit of telomerase (hTERT). UV1 contains both CD4 and CD8 epitopes, and immunogenicity is shown in 78% of HLA unselected patients (pts.) in prior studies. UV1 induced expansion of hTERT specific CD4+ T cells that might be relevant in tumors expressing telomerase, theoretically enabling enhanced checkpoint efficacy in pts. with insufficient spontaneously primed T cells. Reciprocally, checkpoint inhibitor may support the UV1-induced T cells and provide increased effector activity, as these cells may be restricted by intrinsic and tumor-induced suppressor mechanisms. Methods: UV1 was combined with standard of care pembrolizumab in pts. with advanced melanoma. The primary objective of this phase I, multicenter study (NCT03538314), was to evaluate safety and tolerability of UV1 in combination with standard pembrolizumab. Secondary objective was evaluation of response rate (RR) according to iRECIST. Pts. received, in a serial manner, adjuvant GM-CSF and UV1 (300μg) intradermally followed by pembrolizumab. The first 3 UV1/GM-CSF doses were given during week 1, and from week 2 in combination with pembrolizumab (Q3W). Two different doses of GM-CSF were investigated: 37.5μg (20 pts. cohort 1) and 75μg (10 pts. cohort 2). Totally 8 UV1/GM-CSF vaccinations per pt. were planned (14 weeks). Results: In total 30 pts. were enrolled; cohort 1 (N = 20); cohort 2 (N = 10). The abstract reports cohort 1 results. The majority of adverse events (AEs) reported was grade 1 or 2 (48%, 41%). Main AEs were fatigue (8%), injection site reaction (5%), diarrhea (4%) and pyrexia (3%). 18% and 30% of AEs were possibly/definitely related to UV1 or pembrolizumab, respectively. Three patients experienced SAE, one (inflammatory arthritis) was considered possibly related to UV1. No severe allergic reactions were observed. Pembrolizumab was continued after completion of UV1 treatment in 14 pts. for a mean of 8.2 months (range 3-21). Four pts. discontinued pembrolizumab due to PD, one for irAE and one for unknown reason. The RR was 60%, with 5 CRs, and the 1-year survival rate 85 %. Conclusions: Results from cohort 1 (N = 20) show that the treatment of UV1 together with pembrolizumab was safe and well tolerated in patients with advanced melanoma. Updated data with minimum 18 months follow-up will be presented at the conference. Cohort 2 results will be presented at a later stage. Clinical trial information: NCT03538314. [Table: see text]

BACKGROUND: In KEYNOTE-002, pembrolizumab significantly prolonged progression-free survival and was associated with a better safety profile compared with chemotherapy in patients with advanced melanoma that progressed after ipilimumab. We present health-related quality of life (HRQoL) outcomes from KEYNOTE-002.METHODS: Patients were randomly assigned 1:1:1 to pembrolizumab 2 or 10 mg/kg every 3 weeks (Q3W) or investigator-choice chemotherapy. HRQoL was assessed using the European Organisation for Research and Treatment of Cancer Quality-of-Life Questionnaire-Core 30 instrument. A constrained longitudinal data analysis model was implemented to assess between-arm differences in HRQoL scores. The study is registered with ClinicalTrials.gov, number NCT01704287.RESULTS: Of the 540 patients enrolled, 520 were included in the HRQoL analysis. Baseline global health status (GHS) was similar across treatment arms. Compliance rates at week 12 were 76.6% (n = 108), 82.3% (n = 121), and 86.4% (n = 133) for the control, pembrolizumab 2 mg/kg Q3W, and pembrolizumab 10 mg/kg Q3W arms, respectively. From baseline to week 12, GHS/HRQoL scores were maintained to a higher degree in the pembrolizumab arms compared with the chemotherapy arm (decrease of -2.6 for each pembrolizumab arm versus -9.1 for chemotherapy; P = 0.01 for each pembrolizumab arm versus chemotherapy). Fewer patients treated with pembrolizumab experienced deterioration in GHS at week 12 (31.8% for pembrolizumab 2 mg/kg, 26.6% for 10 mg/kg, and 38.3% for chemotherapy), with similar trends observed for the individual functioning and symptoms scales.CONCLUSIONS: HRQoL was better maintained with pembrolizumab than with chemotherapy in KEYNOTE-002, supporting the use of pembrolizumab in patients with ipilimumab-refractory melanoma.

Background: Immune checkpoint inhibitor (ICI) monotherapy shows limited benefit in metastatic triple negative breast cancer (mTNBC) patients (pts), particularly in the second line + setting (ORR ~5-6%, mOS 9 months). In the recent Keynote-119 phase 3 study in 2 or 3L chemorefractory mTNBC pts, pembro monotherapy showed 9.9 month mOS, 9.6% ORR vs 10.8 month mOS, 10.6% ORR for physician's choice chemotherapy. Imprime PGG (Imprime) is a novel, systemically-delivered Beta Glucan agonist of the Dectin Receptor that activates the innate immune system to reprogram the immunosuppressive tumor microenvironment, activate antigen presenting cells and stimulate antigen-specific T cell activation. In preclinical models, Imprime significantly enhances the anti-cancer efficacy of ICI therapy. Accordingly, we sought to explore whether Imprime might enhance the clinical benefit of the ICI, pembro, in 2L+ mTNBC pts. Methods: IMPRIME 1 is an open-label, Simon 2 stage study (12 pts Stage 1, 32 pts Stage 2) with primary completion Dec. 2019. Pts received Imprime (4 mg/kg IV days 1, 8, 15 of each 3-week cycle) + pembro 200 mg on D1 of each cycle. CT scans were taken at baseline and q6wks thereafter until progression. Primary endpoints were ORR (RECIST v1.1) and safety. Secondary endpoints included PFS, OS. Biopsies and blood samples were collected to assess immune activation. Mechanistically, Imprime-mediated activation of innate immune cells requires anti-beta glucan antibodies (ABA). Enrollment was limited to patients having sufficient ABA IgG (≥20mcg/ml). Results Response and Disease Control Rates (Imprime 1 [95% CI]) Overall Response: 15.9% (7.9- 29.4) Stable Disease: 38.6% (25.7-53.4) Progressive Disease: 40.9% (27.7-55.6) Disease Control (CR+PR+SD): 54.5% (40.1-68.3) Disease Control (CR+PR+SD ≥24w): 25.0% (14.6- 39.4) Survival Median Overall Survival (months): 16.4 (11.1- 23.9) 12 Month Survival: 57.6% (42.4-72.8) 18 Month Survival: 36.7% (21.3-52.1) Clinical benefit was pronounced in mTNBC pts previously treated with endocrine therapy (originally ER/PR+ pts). Peripheral blood shows innate immune activation (e.g. increased CD86 on circulating monocytes) and CD8 T cell activation (PD1+/Ki67+/HLA-DR+) as early as 3 wks on therapy. These changes were associated with enhanced PFS and OS. Paired tumor biopsies showed robust infiltration of tumor tissue by activated myeloid cells (Imprime+/PD-L1+/CD80+) and activated CD4, CD8 T cells (Ki67+/granzyme B+). The combination was well-tolerated. Related Gr 3/4 AEs evident in 3/44 pts. The most common Infusion-related reactions were Gr1/2. Conclusion: IMPRIME 1 provides clinical and molecular/ cellular proof of concept data for the combination of Imprime and pembro. These promising data support additional clinical studies in mTNBC pts for this novel Immuno-onocology combination. Citation Format: Steven J. O'Day, Virginia F. Borges, Bartosz Chmielowski, Ruta D. Rao, Maysa Abu-Khalaf, Alison Stopeck, Joyce A. O'Shaughnessy, Michael Chisamore, Vassiliki Karantza, Joanna Cox, Paulette Mattson, Michele A. Gargano, Bruno Osterwalder, Mark Uhlik, Nandita Bose, Jeremy Graff. IMPRIME 1 (NCT02981303): A novel phase 2 study in second-line +, metastatic triple negative breast cancer patients shows promising clinical benefit for the combination of the immune checkpoint inhibitor, pembrolizumab (pembro), with the novel innate immune activator, Imprime PGG [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT073.

Background: AST-008 is a novel spherical nucleic acid configuration of a toll-like receptor 9 (TLR9) agonist oligonucleotide, designed to trigger anti-tumor immune responses. Here we focus on immune activation upon AST-008 injection in the phase 1b/2 study in patients with advanced solid tumors (NCT03684785). Materials and Methods: AST-008 was injected intratumorally (IT) into one or more tumors QW for 8 doses, then Q3W thereafter, at doses from 2 to 32 mg. Starting at week 3, pembrolizumab was administered per label until toxicity or progression. Peripheral blood immune cell profiling and cytokine/chemokine analyses were performed before and 24 hours after both the first AST-008 dose (week 1) and the first combination dose (week 3). Serial tumor biopsies of lesions were collected from both AST-008-injected lesions and non-injected (“witness”) lesions at baseline, after IT AST-008 monotherapy, and after combination therapy. Results: Seventeen patients have been enrolled in the dose escalation cohort: median age 66 [range: 30-86], 82% male, median ECOG 1 [0-1]. Dose dependent lymphocyte activation was observed after IT AST-008. AST-008 dosing alone (16 mg cohort, n = 3) increased activated fractions of CD4+ (33%) and CD8+ T cells (64%), monocytes (97%) and NK cells (94%), compared to baseline (15%, 22%, 4%, and 37%, respectively). At AST-008 doses of 8 and 16 mg, the cell activation response within a dose level was generally similar in the presence or absence of pembrolizumab. In addition, the cytokines/chemokines IL-12p40, IL-1RA, IP-10, and MCP-1 were induced in a dose-proportional manner after IT AST-008 mono- or combination therapy. IT AST-008 resulted in average fold increase of 5, 12, and 16 for doses of 2, 4, and 8 mg dose cohorts, respectively, in IP-10 concentration from baseline (n = 11). Generally, combination therapy with pembrolizumab and AST-008 at doses of 2 and 4 mg produced a cytokine/chemokine response that was smaller than AST-008 alone (n = 5), but 8 mg dose responses were similar after monotherapy or combination therapy (n = 3). Preliminary analysis of serial biopsies by Nanostring revealed increased T cells and cytotoxic cells in the injected lesion after AST-008 dosing (n = 4) and in the non-injected witness lesion after combination therapy (n = 6). Combination therapy produced increases in B cells, T cells, cytotoxic cells and macrophages the AST-008 injected lesions (n = 6). Further PD data are being collected. The emerging safety profile consists mostly of grade (G) 1 and 2 injection site reactions and flu-like symptoms, reflecting local and systemic immune activation. One G3 lymphocytopenia has been observed, with no clinical consequences. No AST-008-related serious AEs or DLTs have been reported. Conclusions: IT AST-008 is well tolerated at the doses administered and is associated with dose-proportional systemic immune activation. Gene expression analysis suggests increased lymphocytes in the injected tumor after IT AST-008 and in both injected and witness tumors after combination therapy. Citation Format: Mohammed M. Milhem, Cesar A. Perez, Glenn J. Hanna, Trisha M. Wise-Draper, Shailender Bhatia, Alice S. Bexon, Weston L. Daniel, Steven J. O'Day. Phase 1b/2 study of an intratumoral TLR9 agonist spherical nucleic acid (AST-008) and pembrolizumab: Evidence of immune activation [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-140.

TPS3164 Background: AST-008 is a potent spherical nucleic acid configuration of a toll-like receptor (TLR) 9 agonist oligonucleotide being developed for the treatment of MCC and CSCC in patients (pts) progressing on immune checkpoint inhibitor (CPI) monotherapy. Previously presented data suggests AST-008 elicits a Th1-type cytokine response and immune cell activation. This parallel-arm phase II design will permit assessment of efficacy in two advanced skin cancers with high unmet medical need. Methods: The study has an open label, multicenter phase Ib/II dose escalation/expansion design. The phase 1b dose escalation used a 3+3 design with increasing doses of intratumoral (IT) AST-008 plus standard flat dose pembrolizumab. The phase II dose expansion is using the recommended regimen (RP2D) of IT AST-008 plus flat dose pembrolizumab or cemiplimab to treat two cohorts of pts with advanced/metastatic MCC or CSCC, respectively. The key objective of the phase II expansion is to provide an estimate of preliminary efficacy of IT AST-008 with pembrolizumab or cemiplimab in pts whose disease progressed on a single-agent CPI therapy. Endpoints also include safety, pharmacokinetic and pharmacodynamic assessments. Pts must have at least two evaluable lesions by RECIST v1.1. One or more lesions may be injected with AST-008, but one lesion (the “witness” lesion) must remain un-injected throughout the study to differentially assess effects of AST-008 on the injected and witness lesions. The RP2D of AST-008 was derived from the dose escalation phase together with pembrolizumab. That RP2D is being used not only in the MCC cohort where AST-008 is combined with pembrolizumab, but also in the CSCC cohort where AST-008 is combined with cemiplimab. To ensure safety of the AST-008/cemiplimab combination, the first 6 pts in the CSCC cohort will be monitored for dose limiting toxicities through the first 5 weeks of dosing, and then the data review committee will assess safety before approving additional patient enrollment to that cohort. Each expansion cohort will enroll up to 29 pts with a Simon two-stage optimal design. In the first stage, 10 pts will be accrued. If there are 0 responses in these 10 pts, enrollment in that arm will be stopped. Otherwise, 19 additional pts will be accrued for a total of 29. The null hypothesis will be rejected if 4 or more responses are observed in 29 pts. This design yields a type I error rate of 0.05 and power of 80% when the true response rate is 20%. The planned phase II enrollment is 58 pts across about 15 US-based sites. Clinical trial information: NCT03684785 .

TPS3157 Background: AGEN1181 is a novel Fc-optimized anti-CTLA4 antibody, currently being evaluated in an ongoing multi-center, open-label, phase 1 study in all advanced solid tumors as mono-therapy and combination with anti-PD-1 antibody, AGEN2034 (NCT03860272). AGEN1181 is Fc-engineered to harness a novel mechanism for enhanced FcγR-dependent functionality relative to first-generation CTLA-4 antibodies. In pre-clinical models, AGEN1181 enhances T cell priming, depletion of intratumoral regulatory T cells (Treg) and improved memory formation compared to first-generation anti-CTLA-4 antibodies. Most notably, AGEN1181 demonstrates improved binding to FcyRIIIA and superior T cell responsiveness in populations that only express the low affinity FcγRIIIA receptor relative to first-generation IgG1 CTLA-4 antibodies. The combination of AGEN1181 and AGEN2034 further enhances T cell activation and effector function. Methods: This phase 1 study is an open-label, multi-center dose-escalation designed to evaluate the safety, tolerability, dose limiting toxicity (DLT) PK, and pharmacodynamic profiles of patients with refractory advanced solid tumors who did not receive an anti-CTLA4 previously. The study is being conducted in 3 arms; with patients assigned using a standard 3+3 dose escalation design in the mono-therapy arms with AGEN1181 and an accelerated design in the combination with AGEN2034 arm. AGEN1181 is administered as IV infusion as mono-therapy on Day 1 of every 3 weeks (0.1,0.3,1,2,4 mg/kg), every 6-weeks (1,2,4 mg/kg) in parallel cohorts and every 6-weeks (0.1,0.3,1,2,4 mg/kg) in combination with AGEN2034 (3mg/kg Q2Weeks) until disease progression or unacceptable toxicity (maximum 2 years). All 3 Arms are open and enrolling patients. The study is expected to enroll approximately 80 evaluable patients with solid tumors. Dose reductions are not allowed in the event of AGEN1181-related toxicities. Currently 3 cohorts have been completed, first cohort in the combination arm and the fourth cohort in the monotherapy arm are enrolling. Preclinical and clinical assessment of AGEN1181 supports continued development as a potential therapy for refractory or relapsed advanced solid tumors. Clinical trial information: NCT03860272 .

TPS3161 Background: VV1 is an oncolytic vesicular stomatitis virus engineered to express human IFNβ to enhance cellular anti-tumor immune responses and tumor selectivity, and the human sodium iodide symporter (NIS) for virus tracking by SPECT imaging. Cancer cells are often hyporesponsive to IFNβ, enabling the efficient spread of VV1 and resulting in increased oncolysis. Differently from other oncolytic viruses, VV1 is suitable for both intra-tumoral (IT) and/or intra-venous (IV) administration. Despite considerable anti-tumor activity with checkpoint inhibitors (CPI) among some malignancies, long term survival and overall cures remain elusive. Prior Ph 1 studies have shown significant anti-tumor activity among several malignancies when VV1 was administered either as monotherapy or in combination with a CPI, despite progression on prior CPI monotherapy. Furthermore, pre- and post-treatment biopsy evaluations after VV1 treatment have demonstrated T cell infiltration and inflammation in both IT injected and non-injected lesions. Among IV treated patients (pts), IFNβ was detectable in the serum correlating with viral replication, making it an effective biomarker. C is a high-affinity potent human IgG4 anti-PD-1 monoclonal antibody. Though approved for use in cutaneous squamous cell carcinoma, C has shown anti-tumor activity, similar to other CPI, in several other indications. Therefore, VV1 and C could be an attractive combination for the immunotherapy for several solid tumors. This study represents the first clinical evaluation of VV1 in combination with C in pts with advanced solid tumors. Methods: The Ph 2 Simon 2 stage five-arm study of IV administration VV1 in combination with IV C will enroll pts with advanced NSCLC, HCC, melanoma & endometrial cancer. Enrolled pts with NSCLC & melanoma will be recent CPI-progressors, whereas enrolled HCC & endometrial cancer will be CPI-naïve. The study’s objectives include assessment of preliminary anti-tumor activity, safety, & immuno-regulatory activity of the combination. Pts will receive IV VV1 once on D1 and IV C once every 3 weeks until confirmed disease progression or intolerable toxicity. Pts enrolled in one melanoma cohort will also receive IT VV1 administered to palpable lesions. Response will be assessed every 9 weeks per RECIST v1.1. The null hypothesis of each cohort’s ORR will be tested versus a one-sided alternative yielding a Type I error rate of 5% and power of 80%. Cohorts will be expanded based on signal of activity. Clinical trial information: NCT .

The pandemic caused by the novel coronavirus SARS-CoV-2 has placed an unprecedented burden on healthcare systems around the world. In patients who experience severe disease, acute respiratory distress is often accompanied by a pathological immune reaction, sometimes referred to as ‘cytokine storm’. One hallmark feature of the profound inflammatory state seen in patients with COVID-19 who succumb to pneumonia and hypoxia is marked elevation of serum cytokines, especially interferon gamma, tumor necrosis factor alpha, interleukin 17 (IL-17), interleukin 8 (IL-8) and interleukin 6 (IL-6). Initial experience from the outbreaks in Italy, China and the USA has anecdotally demonstrated improved outcomes for critically ill patients with COVID-19 with the administration of cytokine-modulatory therapies, especially anti-IL-6 agents. Although ongoing trials are investigating anti-IL-6 therapies, access to these therapies is a concern, especially as the numbers of cases worldwide continue to climb. An immunology-informed approach may help identify alternative agents to modulate the pathological inflammation seen in patients with COVID-19. Drawing on extensive experience administering these and other immune-modulating therapies, the Society for Immunotherapy of Cancer offers this perspective on potential alternatives to anti-IL-6 that may also warrant consideration for management of the systemic inflammatory response and pulmonary compromise that can be seen in patients with severe COVID-19.

INTRODUCTION: To determine the recommended Phase II dose of RRx-001, a radiosensitizer with vascular normalizing properties, when used with whole-brain radiation therapy (WBRT) for brain metastases, and to assess whether quantitative changes in perfusion MRI after RRx-001 correlate with response. METHODS AND MATERIALS: Five centers participated in this phase I/II trial of RRx-001 given once pre-WBRT then twice weekly during WBRT (30 Gy/10 fractions). Four dose levels were planned (5 mg/m2, 8.4 mg/m2, 16.5 mg/m2, 27.5 mg/m2). Dose-escalation was managed by the Time-to-Event Continual Reassessment Model (TITE-CRM). Correlative DCE-MRI was performed in a subset of patients and linear mixed models used to correlate change in 24-hour T1, Ktrans (capillary permeability) and Vp (plasma volume) with change in tumor volume. RESULTS: Between 2015–2017, 31 patients were enrolled. Two patients dropped out prior to any therapy and 7 were treated with concurrent temozolomide following a study amendment. Median age was 60 years (range, 30–76) and 17 were male. The most common tumor types were melanoma (58%) and non-small cell lung cancer (20%). No dose-limiting toxicities were observed. The most common severe adverse event was grade 3 asthenia in 6.9% (2/29). The median intracranial response rate was 46% (95%CI 24–68) and median overall survival was 5.2 months (95%CI 4.5–9.4). No neurologic deaths occurred. Among 10 evaluable patients undergoing DCE-MRI, a reduction in Vp 24 hours after RRx-001 was associated with reduced tumor volume at 1 month and 4 months (p≤0.01). CONCLUSION: The addition of RRx-001 to WBRT is safe and well-tolerated with favorable intracranial response rates. Because activity was observed across all dose levels, and in the absence of a dose response, the recommended Phase 2 dose is 10 mg administered twice weekly. A reduction in Vp by DCE-MRI 24 hours after RRx-001 suggests anti-angiogenic activity that is associated with longer-term tumor response.

Objectives This study was an open-label multicenter phase II trial to investigate the efficacy and safety of nab-paclitaxel and bevacizumab as first-line therapy in patients with histologically confirmed unresectable metastatic melanoma. Methods The treatment regimen consisted of a 28-day cycle in which patients received nab-paclitaxel, 150 mg/m through intravenous (IV) infusion weekly for 3 weeks and bevacizumab, 10 mg/kg IV every 2 weeks without a rest period. The 28-day cycle was repeated until there was unacceptable toxicity or disease progression. If 1 drug had to be stopped because of toxicity, treatment was continued with the other drug until disease progression or unacceptable toxicity. The primary endpoint was the progression-free survival rate (PFS) at 4 months. Results Fifty patients were enrolled. The PFS rate at 4 months was 75%. The median PFS was 7.6 months and the median overall survival was 16.8 months with a median duration follow-up of 41.6 months. The overall survival rate was 64% at 1 year and 30% at 2 years. Ten patients (20%) remain alive. The objective response rate was 36%. Common adverse events associated with this regimen were peripheral neuropathy, fatigue, alopecia, and gastrointestinal disorders. Conclusions In this phase II multicenter study, this doublet had significant activity in patients with metastatic melanoma, and was well tolerated. These results are promising and follow-up trials to further explore this regimen are warranted.

KEYNOTE-030 (ClinicalTrials.gov ID, NCT02083484) was a global expanded access program that allowed access to pembrolizumab, an antiprogrammed death 1 antibody, for patients with advanced melanoma before its regulatory approval. Patients with unresectable stage III/IV melanoma that progressed after standard-of-care therapy, including ipilimumab and, if BRAFV600 mutant, a BRAF inhibitor, were eligible to receive pembrolizumab 2 mg/kg every 3 weeks. Response was assessed by immune-related response criteria by investigator review. Adverse events (AEs) were graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0. In the United States, 979 patients enrolled between April and September 2014. Of the 947 evaluable patients, 621 (65.6%) remained on treatment and transitioned to receive commercial pembrolizumab following approval by the Food and Drug Administration, whereas 326 (34.4%) discontinued, most commonly for disease progression (39.6%) or death (26.4%). Objective response rate was 14.5% (95% confidence interval, 12.2%–16.8%) in the treated population (n=947) and 22.1% (95% confidence interval, 18.8%–25.5%) in patients who had ≥1 response assessment reported (n=619). Twelve patients achieved complete response. One hundred eighty-one (19.1%) patients experienced ≥1 treatment-related AE, most commonly general disorders (8.0%), skin/subcutaneous tissue disorders (7.3%), and gastrointestinal disorders (6.4%); 29 (3.1%) patients experienced ≥1 grade 3/4 treatment-related AE. Immune-mediated AEs were also reported. There were no treatment-related deaths. The safety and efficacy observed in this expanded access program were consistent with those previously reported for similar populations and support the use of pembrolizumab for patients with advanced melanoma.

Purpose: Dabrafenib is a selective, potent ATP-competitive inhibitor of the BRAFV600-mutant kinase that has demonstrated efficacy in clinical trials. We report the rationale for dose selection in the first-in-human study of dabrafenib, including pharmacokinetics, tissue pharmacodynamics, 2[18F]fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) pharmacodynamics, and dose–response relationship. Experimental Design: Dabrafenib was administered orally once, twice (BID), or three times daily (TID). Selected dose cohorts were expanded to collect adequate data on safety, pharmacokinetics, or pharmacodynamics. A recommended phase II dose (RP2D) was chosen based on safety, pharmacokinetic, pharmacodynamic, and response data. Results: One hundred and eighty-four patients were enrolled and treated with doses ranging from 12 mg once daily to 300 mg BID in 10 cohorts. Pharmacokinetic assessment of dabrafenib demonstrated a less-than-dose-proportional increase in exposure after repeat dosing above 150 mg BID. Similar to parent drug concentrations, exposure for all metabolites demonstrated less-than-dose-proportional increases. Predicted target inhibition of pERK (>80%) was achieved at 150 mg BID, with a similar magnitude of inhibition at higher doses in BRAFV600 mutation melanoma biopsy samples. Although there was large variability between patients, FDG uptake decreased with higher daily doses in patients with BRAFV600 mutation–positive melanoma. A favorable activity and tolerability profile was demonstrated at 150 mg BID. There was no improvement with TID dosing compared with BID dosing, based on FDG-PET and tumor response analyses in patients with melanoma. Conclusion: The RP2D of dabrafenib was determined to be 150 mg BID after considering multiple factors, including pharmacokinetics, tissue pharmacodynamics, FDG-PET pharmacodynamics, and the dose–response relationship. A maximum tolerated dose for dabrafenib was not determined. Clin Cancer Res; 20(17); 4449–58. ©2014 AACR.

Summary Background Recent phase 3 trials have shown an overall survival benefit in metastatic melanoma. We aimed to assess whether progression-free survival (PFS) could be regarded as a reliable surrogate for overall survival through a meta-analysis of randomised trials. Methods We systematically reviewed randomised trials comparing treatment regimens in metastatic melanoma that included dacarbazine as the control arm, and which reported both PFS and overall survival with a standard hazard ratio (HR). We correlated HRs for overall survival and PFS, weighted by sample size or by precision of the HR estimate, assuming fixed and random effects. We did sensitivity analyses according to presence of crossover, trial size, and dacarbazine dose. Findings After screening 1649 reports and meeting abstracts published before Sept 8, 2013, we identified 12 eligible randomised trials that enrolled 4416 patients with metastatic melanoma. Irrespective of weighting strategy, we noted a strong correlation between the treatment effects for PFS and overall survival, which seemed independent of treatment type. Pearson correlation coefficients were 0·71 (95% CI 0·29–0·90) with a random-effects assumption, 0·85 (0·59–0·95) with a fixed-effects assumption, and 0·89 (0·68–0·97) with sample-size weighting. For nine trials without crossover, the correlation coefficient was 0·96 (0·81–0·99), which decreased to 0·93 (0·74–0·98) when two additional trials with less than 50% crossover were included. Inclusion of mature follow-up data after at least 50% crossover (in vemurafenib and dabrafenib phase 3 trials) weakened the PFS to overall survival correlation (0·55, 0·03–0·84). Inclusion of trials with no or little crossover with the random-effects assumption yielded a conservative statement of the PFS to overall survival correlation of 0·85 (0·51–0·96). Interpretation PFS can be regarded as a robust surrogate for overall survival in dacarbazine-controlled randomised trials of metastatic melanoma; we postulate that this association will hold as treatment standards evolve and are adopted as the control arm in future trials. Funding None.

Background This ongoing trial is investigating the safety and efficacy of combining the therapeutic cancer vaccine UV1 with the anti-PD-1 mAb pembrolizumab. UV1 is a peptide-based vaccine directed against telomerase, an essential enzyme for unlimited cell-division and a hallmark of cancer. Due to its selective expression, telomerase serves as a unique cancer antigen. UV1 consists of 3 long peptides (15-30 aa) representing fragments of the reverse transcriptase subunit of telomerase (hTERT). The peptides contain both CD4 and CD8 epitopes and are shown to be immunogenic in 78% of HLA unselected patients across different cancer types. UV1 induces hTERT-specific tumor-reactive T cells, and has the potential to induce epitope spreading. UV1 can increase the efficacy of checkpoint inhibitors in patients with insufficient numbers of T cells spontaneously primed by tumor antigens. Reciprocally, the efficacy of UV1 may be enhanced by checkpoint inhibitors, since the effector activity of UV1-induced T cells will be restricted by intrinsic and tumor-induced suppressor mechanisms. UV1 and pembrolizumab thus have the potential to produce synergistic immunological activity which may provide increased clinical benefit as compared to pembrolizumab alone. Trial design The ongoing phase I, open-label, multicenter study is planned to include 20 patients with untreated unresectable or metastatic melanoma. UV1 (300 μg) with GM-CSF (37,5 μg) as adjuvant is administered intradermally for a total of 8 doses, 3 doses during week 1, and one dose during week 2, 3, 8, 11 and 14. Pembrolizumab is administered every third week starting week 2 for up to two years or until progressive disease. Patients are followed for up to 2 years after the first UV1 dose. The primary objective of the study is to evaluate the safety and tolerability of the UV1 and pembrolizumab therapy. Secondary objectives are UV1 vaccine-specific immune responses and evaluation of tumor response (RECIST). Samples of blood, feces, and tumor tissue are collected for translational research purposes. Clinical trial identification NCT03538314. Legal entity responsible for the study Ultimovacs AS. Funding Ultimovacs AS. Disclosure Y. Zakharia: Advisory / Consultancy: Amegen; Advisory / Consultancy: Roche Diagnostics; Advisory / Consultancy: Novartis; Advisory / Consultancy: JNJ; Advisory / Consultancy: Eisai; Advisory / Consultancy: Exelixis; Advisory / Consultancy: Castle Bioscience; Advisory / Consultancy: Pfizer; Advisory / Consultancy: Bayer; Advisory / Consultancy: Array. All other authors have declared no conflicts of interest.

Background Pembro, a PD-1 inhibitor, has shown effective antitumor activity, durable responses, and survival benefit in pts with advanced melanoma. Len—a potent inhibitor of VEGF receptors 1-3, FGF receptors 1-4, PDGF receptor α, RET, and KIT—plus a PD-1 inhibitor showed superior antitumor efficacy to either agent alone in a murine tumor model. Len + pembro showed antitumor activity and was well tolerated in pts with advanced melanoma in the phase Ib/II KEYNOTE-146 trial. LEAP-003 will compare the efficacy and safety of pembro ± len in advanced melanoma (NCT03820986). Trial design Eligibility criteria include ≥18 y, histologically/cytologically confirmed unresectable untreated stage III-IV melanoma, documented BRAFV600 status, ECOG performance status 0/1, toxicity resolution from most recent therapy, and provision of baseline tumor sample. Prior first-line standard of care targeted therapy allowed only if pt has BRAFV600-mutant disease. Prior targeted therapy or immunotherapy (as adjuvant/neoadjuvant) allowed if relapse did not occur during treatment or ≤ 6 mo after discontinuation. Pts will be randomized 1:1 to pembro 200 mg every 3 weeks (Q3W) IV plus len 20 mg or placebo QD PO. Randomization will be stratified by BRAF status (mutant/WT), prior adjuvant therapy (PD-1 inhibitor, yes/no), geographic region (China, yes/no). Pembro will continue for up to ∼2 y; len or placebo may continue beyond 2 y in cases of clinical benefit, until progression, unacceptable toxicity, or investigator/pt decision. Response will be assessed per RECIST v1.1 Q9W until wk 54, Q12W until wk 102, and Q24W thereafter. Pts with a CR can discontinue treatment after ≥24 wk of pembro and ≥2 pembro doses after initial CR. Eligible pts can continue treatment beyond initial RECIST-defined PD. AEs will be assessed for ≤90 d and graded per NCI CTCAE v4.0. Survival follow-up will be Q12W. Primary end points are PFS by blinded independent central review (BICR) per modified RECIST v1.1 (max target lesions: 10; 5 per organ) and OS. Secondary end points are ORR and DOR (by BICR per modified RECIST v1.1), safety, and pt-reported health outcomes. Exploratory biomarker and PK analyses of len plus pembro are planned. Clinical trial identification NCT03820986; release date: January 29, 2019. Editorial acknowledgement Doyel Mitra, PhD, CMPP, and Harleigh E. Willmott, PhD, CMPP, of the ApotheCom pembrolizumab team (Yardley, PA, USA). Legal entity responsible for the study Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Funding Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA. Disclosure A.M.M. Eggermont: Honoraria (self): Actelion, BMS, GSK, Ellipses, Incyte, IO Biotech, IsaPhamaceuticals, MSD, Novartis, Pfizer, Sanofi, Sellas, SkylineDx; Advisory / Consultancy: Actelion, BMS, GSK, Ellipses, Incyte, IO Biotech, IsaPhamaceuticals, MSD, Novartis, Pfizer, Sanofi, Sellas, SkylineDx; Speaker Bureau / Expert testimony: MSD. M.S. Carlino: Honoraria (self): MSD, BMS; Advisory / Consultancy: MSD, BMS, Novartis, Roche, Merck, Pierre Fabre. A. Hauschild: Honoraria (self): Amgen, BMS, MSD/Merck, Novartis, Pierre Fabre, Provectus, Regeneron, Roche, Sanofi-Genzyme; Honoraria (institution), Support for clinical trials: Amgen, BMS, MerckSerono, MSD/Merck, Novartis, Philogen, Pierre Fabre, Provectus, Regeneron, Roche, Sanofi-Genzyme; Advisory / Consultancy: Amgen, BMS, MerckSerono, MSD/Merck, Novartis, Philogen, Pierre Fabre, Provectus, Regeneron, Roche, OncoSec, Sanofi-Genzyme, Sun Pharma. P.A. Ascierto: Advisory / Consultancy: BMS, Roche-Genentech, MSD, Array, Novartis, Merck Serono, Pierre Fabre, Incyte, Genmab, Newlink Genetics, MedImmune, AstraZeneca, Syndax, Sun Pharma, Sanofi, Idera, Ultimovacs, Sandoz, Immunocore, 4SC; Research grant / Funding (self): BMS, Roche-Genentech, Array; Travel / Accommodation / Expenses: MSD. A. Arance: Advisory / Consultancy: BMS, MSD, Roche, Novartis, Merck; Travel / Accommodation / Expenses: BMS, MSD, Roche, Novartis, Merck. A. Daud: Advisory / Consultancy: Merck, Pfizer, BMS, Genentech, Incyte, Novartis; Shareholder / Stockholder / Stock options: SQZ; Research grant / Funding (self): BMS, Pfizer, Incyte, Checkmate, Merck. S.J. O’Day: Advisory / Consultancy: Biothera, BMS, Merck, RadImmune, ImaginAB; Speaker Bureau / Expert testimony: BMS; Travel / Accommodation / Expenses: Biothera, BMS, Merck, RadImmune, ImaginAB; Research grant / Funding (institution): Amgen, Biothera, Exicure, Genocea, Incyte, Oncothereapeutics, Ultimovacs, Viralytics. M.H. Taylor: Honoraria (self): BMS, Eisai Inc, Array Biopharma, Arqule, Blueprint Medicines, Bayer, Loxo Oncology, Novartis; Advisory / Consultancy: BMS, Eisai Inc, Array Biopharma, Arqule, Blueprint Medicines, Bayer, Loxo Oncology, Novartis; Speaker Bureau / Expert testimony: BMS, Eisai Inc. A. Smith: Full / Part-time employment: Eisai. A. Rodgers: Full / Part-time employment: Merck & Co., Inc. B. Homet Moreno: Shareholder / Stockholder / Stock options, Full / Part-time employment: Merck & Co., Inc. S.J. Diede: Shareholder / Stockholder / Stock options, Full / Part-time employment: Merck & Co., Inc. H. Kluger: Research grant / Funding (institution): Merck, BMS, Apexigen; Honoraria (self): Regeneron, Alexion, Prometheus, Corvus, Nektar, Biodesix, Roche/Genentech, Pfizer, Iovance, Immunocore, Celldex, Array BioPharma.

9514 Background: KEYNOTE-029 cohort 1B showed substantial efficacy for standard-dose pembro + 4 doses of ipi 1 mg/kg with lower rate of grade 3-5 toxicity than reported for standard-dose nivolumab + ipi in patients (pts) with advanced melanoma. In KEYNOTE-029 cohort 1C, we assessed the toxicity and antitumor activity of standard-dose pembro plus 2 alternate ipi doses (NCT02089685). Methods: Eligible pts with previously untreated stage III/IV melanoma, ECOG PS 0-1, and no active CNS metastases were randomized 1:1 to pembro 200 mg Q3W for 24 mo + 4 doses of ipi 50 mg Q6W (arm A) or pembro 200 mg Q3W for 24 mo + 4 doses of ipi 100 mg Q12W (arm B). Primary endpoints were the grade 3-5 treatment-related AE (TRAE) rate and ORR (RECIST v1.1, central review). With 50 pts per arm and compared with other anti–PD-1 + ipi regimens, a grade 3-5 TRAE rate ≤26% would suggest a meaningful reduction in toxicity and an ORR ≥48% would suggest no decrease in efficacy. Data cutoff date was Jul 17, 2018, and will be updated. Results: 102 pts were randomized: 51 to each arm. Median age was 63.5 y, 70% were male, 15% had ECOG PS 1, 34% had BRAF mutation, and 30% had elevated LDH at baseline. With 9.4 mo median follow-up, 69% of pts in arm A and 71% in arm B remained on treatment. All pts in arm A and 96.1% in arm B had ≥1 TRAE; grade 3-5 TRAE rates were 22% in arm A and 33% in arm B. 1 pt had a grade 5 TRAE (autoimmune myocarditis; arm A). ORR was 49% (95% CI 35-63) in arm A, including 7 CRs and 18 PRs, and 53% (95% CI 39-67) in arm B, including 6 CRs and 21 PRs. An additional 16 pts in each arm had SD or non-CR/non-PD, leading to a DCR of 80% and 84%, respectively. Median response duration was not reached in either arm (range 1.4+ to 9.6+ in arm A, 1.4+ to 9.8+ in arm B). Updated data based on longer follow-up will be presented. Conclusions: Standard-dose pembro + ipi 50 mg Q6W and standard-dose pembro + ipi 100 mg Q12W showed robust antitumor activity in this initial analysis. Both regimens appeared to have a lower rate of grade 3-5 TRAEs than previously observed. Longer follow-up and randomized studies are needed to confirm that these regimens reduce toxicity without compromising efficacy compared with other anti–PD-1 and ipi combinations. Clinical trial information: NCT02089685.

2550 Background: Checkpoint inhibitor (CPI) monotherapy shows limited clinical response in previously treated mTNBC patients (pts) (Table). Agents are needed that extend this benefit to more mTNBC pts. PGG is a novel, IV administered PAMP that, in pts with 20ug/ml anti-beta glucan antibody (ABA+), activates innate immune cells. Preclinically, PGG reprograms myeloid cells to repolarize the immunosuppressive tumor microenvironment & enhance antigen presentation, driving T cell activation- the mechanistic basis to explore PGG + P in mTNBC patients. Methods: 44 mTNBC pts ( 1 line of chemotherapy [Tx] for metastatic disease, ABA) received PGG (4 mpk IV weekly) + P (200 mg IV q3w) until PD or intolerable toxicity. 1° endpoints were ORR by RECIST v1.1 & safety. 2° endpoints included OS & DCR. CT scans (q6 wks) were reviewed locally. Tumor biopsies (pre & 6 wks on Tx) & blood samples were assessed for PGG-mediated immune activation. Results: Table shows IMPRIME 1 clinical response data (Keynote086, PCD4989g shown for context). Confirmed response was also evident in pts with liver or visceral metastases, high LDH. 10 IMPRIME 1 pts were originally ER/PR+, received hormonal Tx and progressed to TNBC. Of these, 5 are confirmed PR, 4 SD (3 still on Tx), 1 PD. No unexpected safety signals were observed. Conclusions: These are the first clinical data to suggest that PGG provides added clinical benefit for pts with previously treated mTNBC and support further development of PGG + P for mTNBC. Clinical trial information: NCT02981303. [Table: see text]

TPS9594 Background: Pembro, a PD-1 inhibitor, has shown effective antitumor activity, deep and durable responses, and survival benefit in treatment-naive pts and those with previously treated metastatic melanoma. Len, a potent inhibitor of VEGF receptors 1-3, FGF receptors 1-4, PDGF receptor α, RET, and KIT, combined with a PD-1 inhibitor showed antitumor activity superior to either agent alone in preclinical models of colorectal and lung cancer. Additionally, len plus pembro showed anti-tumor activity and was well-tolerated (24-wk ORR, 47.6%; TRAE: gr 3/4, 67%; gr 5, 0%) in pts with advanced melanoma previously treated with 0-2 therapies in the phase 1b/2 KEYNOTE-146 trial. The efficacy and safety of len plus pembro combination therapy will be evaluated in an open-label, phase 2 trial of pts with advanced melanoma that progressed on PD-1/PD-L1 inhibitor therapy (NCT03776136). Methods: Key inclusion criteria: age ≥18 years, histologically/cytologically confirmed unresectable stage III-IV melanoma that progressed (per iRECIST) within 12 weeks of last dose of an approved PD-1/PD-L1 inhibitor therapy (≥2 doses as monotherapy or combined with other therapies), measurable disease, ECOG PS 0/1, no active autoimmune disease, and adequate organ function. Pts must provide a baseline tumor sample. Pts will receive len 20 mg/day orally plus pembro 200 mg IV Q3W for approximately 2 years (35 doses of pembro), after which they may receive len alone until PD or unacceptable toxicity. Response will be assessed per RECIST v1.1 based on blinded independent central review (BICR) Q9W until week 54, Q12W until week 102, and Q24W thereafter. Pts with CR may discontinue treatment after ≥24 weeks of therapy; eligible pts may continue treatment beyond initial RECIST- or iRECIST-defined PD. AEs will be assessed throughout treatment and for 90 days (120 days for serious AEs) after last dose and graded per NCI CTCAE v4.0. Pts will be followed-up for survival status Q12W. The primary efficacy end point is ORR per modified RECIST v1.1 (BICR). Key secondary end points are PFS and DOR per modified RECIST v1.1 (BICR), OS, and safety; an exploratory biomarker analysis is planned. Clinical trial information: NCT03776136.

9565 Background: Nearly 50% of metastatic melanoma patients develop brain metastases, warranting further investigation into the biology of this event. Methods: We analyzed 132 MBM and 745 CM submitted to Caris Life Sciences from 2015-2018, using next generation sequencing of a 44 or 592 cancer-related gene panel, tumor mutational burden (TMB), and PD-L1 expression by IHC. Genomic alterations (GA), including somatic mutations or CNA, were reported. High TMB (TMB-H) was defined as ≥17 mut/Mb. Comparison of molecular profiles, including cancer-related genes and recurrently altered pathways, between tumor sites and by genomic subgroup (BRAF, NRAS, KIT, NF1), was performed using Fisher’s exact test. Results: Among 132 MBM, 72.7% were male, with median age 62 yo (range 25-83). The most common GAs among MBM were: BRAF (52.4%), NRAS (26.6%), CDKN2A (23.3%), NF1 (18.9%), TP53 (18%), ARID2 (13.8%), SETD2 (11.9%), and PBRM1 (7.5%). Compared to CM, MBM were more often TMB-H (53.7% v 38%, p = .025), with higher PD-L1 expression, using both a ≥1% (54.4% v 35.6%, p = .002) and ≥5% cut-off (32.9% v 15.9%, p = .0006). MBM showed higher rates of GAs among: SETD2 (11.9% v 1.9%, p = .0008), BRAF (52.4% v 35.6%, p = .017), PBRM1 (7.5% v 1.6%, p = .018), KRAS (4% v 1%, p = .026), CCND1 (2.9% v 0%, p = .03), and DICER1 (4.4% v 0.6%, p = .04), compared to CM. Alterations of the MAPK (87.9% v 77.8%, p = .015) and SWI/SNF (22.1% v 11.6%, p = .036) pathway were more frequent in MBM, than CM. When analyzed by genomic subgroup, BRAF+ MBM had more GAs involving the PI3K pathway (20% v 5.1%, p = .027), compared to BRAF WT MBM. NRAS+ MBM had higher PD-L1 expression at the ≥1% cutoff (66.7% v 38.6%, p = .05), but not ≥5%, compared to NRAS WT MBM. NF1+ MBM had more GAs involving the SWI/SNF (60% v 11.6%, p = .003) pathway, as opposed to NF1 WT MBM. No significant associations were seen between KIT status, TMB, PD-L1 or other pathways among MBM. Conclusions: In this cross-sectional study, MBM demonstrated higher PD-L1 expression and were more often TMB-H, compared to CM. MBM also featured more GAs involving BRAF and the MAPK pathway. We identified two novel genes, PBRM1 and SETD2, as well as recurrent alterations of the SWI/SNF pathway, supporting future studies of chromatin remodeling pathways in MBM.

Effective management of hepatic metastases from ocular and cutaneous melanoma remains a major therapeutic challenge. Treatment options include hepatic resection, hepatic intra-arterial (HIA) chemotherapy, chemoembolization, and hepatic perfusions. Evaluating the efficacy of these interventions is limited by the retrospective nature of most of the data, although controlled phase 3 studies are starting to emerge. Studies of hepatic resection are strongly suggestive of a survival benefit following surgery in selected patients. Effective systemic agents for metastatic cutaneous melanoma are available and supported by randomized controlled phase 3 trials. In contrast, no active systemic treatment has yet been identified for metastatic ocular melanoma. HIA and intravenous delivery of fotemustine have been compared in a randomized phase 3 trial in patients with unresectable metastases from melanoma, but no differences between the 2 approaches were observed. Hepatic arterial chemoembolization appears only to be moderately effective according to uncontrolled studies; targeting patients with less liver involvement may improve outcomes. A recent phase 3 study showed a significant improvement in hepatic progression-free survival with percutaneous hepatic perfusion compared with best alternative care in patients with metastatic melanoma; however, the overall survival analysis was confounded by crossover of control patients to active treatment. In conclusion, hepatic resection offers the possibility of long-term survival in carefully selected patients with liver-limited metastases from melanoma. In patients with unresectable cutaneous melanoma, effective systemic therapy is the best treatment option. For patients with unresectable ocular melanoma, regional treatments are likely to assume a greater role until effective systemic treatments are identified.