Protocol for the EACH trial: a multicentre phase II study evaluating the safety and antitumour activity of the combination of avelumab, an anti-PD-L1 agent, and cetuximab, as any line treatment for patients with recurrent/metastatic head and neck squamous cell cancer (HNSCC) in the UK

INTRODUCTION

Head and neck cancer is the eighth most common cancer in the UK. Current standard of care treatment for patients with recurrent/metastatic squamous cell head and neck carcinoma (HNSCC) is platinum-based chemotherapy combined with the anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody, cetuximab. However, most patients will have poor median overall survival (OS) of 6-9 months despite treatment. HNSCC tumours exhibit an immune landscape poised to respond to immunotherapeutic approaches, with most tumours expressing the immunosuppressive receptor programmed death-ligand 1 (PD-L1). We undertook the current study to determine the safety and efficacy of avelumab, a monoclonal antibody targeting the interaction between PD-L1 and its receptor on cytotoxic T-cells, in combination with cetuximab.

METHODS AND ANALYSIS

This is a multi-centre, single-arm dose de-escalation phase II safety and efficacy study of avelumab combined with cetuximab; the study was to progress to a randomised phase II trial, however, the study will now complete after the safety run-in component. Up to 16 participants with histologically/cytologically recurrent/metastatic squamous cell carcinoma (including HNSCC) who have not received cetuximab previously will be recruited. All patients will receive 10 mg/kg avelumab and cetuximab (500, 400 or 300 mg/m2 depending on the cohort open at time of registration) on days 1 and 15 of 4-week cycles for up to 1 year, (avelumab not given cycle 1 day 1). A modified continual reassessment method will be used to determine dose de-escalation. The primary objective is to establish the safety of the combination and to determine the optimum dose of cetuximab. Secondary objectives include assessing evidence of antitumour activity by evaluating response rates and disease control rates at 6 and 12 months as well as progression-free and OS.

ETHICS AND DISSEMINATION

Approval granted by City and East REC (18/LO/0021). Findings will be published in peer-reviewed journals and disseminated at conferences.

TRIAL REGISTRATION NUMBER

NCT03494322.

Whole-genome sequencing of single circulating tumor cells from neuroendocrine neoplasms

Single-cell profiling of circulating tumor cells (CTCs) as part of a minimally invasive liquid biopsy presents an opportunity to characterize and monitor tumor heterogeneity and evolution in individual patients. In this study, we aimed to compare single-cell copy number variation (CNV) data with tissue and define the degree of intra- and inter-patient genomic heterogeneity. We performed next-generation sequencing (NGS) whole-genome CNV analysis of 125 single CTCs derived from seven patients with neuroendocrine neoplasms (NEN) alongside matched white blood cells (WBC), formalin-fixed paraffin-embedded (FFPE), and fresh frozen (FF) samples. CTC CNV profiling demonstrated recurrent chromosomal alterations in previously reported NEN copy number hotspots, including the prognostically relevant loss of chromosome 18. Unsupervised hierarchical clustering revealed CTCs with distinct clonal lineages as well as significant intra- and inter-patient genomic heterogeneity, including subclonal alterations not detectable by bulk analysis and previously unreported in NEN. Notably, we also demonstrated the presence of genomically distinct CTCs according to the enrichment strategy utilized (EpCAM-dependent vs size-based). This work has significant implications for the identification of therapeutic targets, tracking of evolutionary change, and the implementation of CTC-biomarkers in cancer.

Abstract LB004: Nivolumab (NIVO) and ipilimumab (IPI) treatment in prostate cancer with an immunogenic signature: cohort 1 of the NEPTUNES multi-centre, two-stage biomarker-selected Phase II trial

Background: Responses to checkpoint inhibitor (CPI) monotherapy in patients with metastatic castration resistant prostate cancer (mCRPC) have been limited. This is likely due to a “cold” tumour immune microenvironment. We hypothesised that patients with mCRPC will be more likely to respond if they have a positive immunogenic signature (ImS+). We report the response/safety for NIVO + IPI in pts with ImS+ mCRPC from cohort 1 of the NEPTUNES study.

Methods: Pts with mCRPC who progressed following ≥1 line of therapy and ImS+ were eligible. ImS+ was defined by ≥1 of the following: 1) mismatch repair deficient (MMRD) by immunohistochemistry (IHC); 2) DNA damage repair deficient (DDRD) excluding MMRD, detected by the UW-OncoPlex targeted exome sequencing assay and; 3) high tumour infiltrating lymphocytes (TILs) on multiplexed immunohistochemistry (CD4, CD8 or FoxP3+ >20% nucleated cells). Treatment was NIVO 1 mg/kg + IPI 3 mg/kg Q3W for 4 doses, then NIVO 480 mg every 4 weeks. Primary endpoint was composite response rate (CRR) defined by ≥1 of the following: 1) radiological response by RECIST 1.1; 2) PSA response ≥50%; 3) conversion of circulating tumour cells (CTC) at week 9. Treatment would be deemed ineffective if the CRR was <20%. Results: 50/211 pts were ImS+, and 35 patients were treated with NIVO/IPI with a median follow up of 7.2 months (range 2.1-20.5). The overall CRR was 9/35 (26%, 95%CI 12-43%). The ImS+ determinants in responding/all treated patients included MMRD (n=4/5), BRCA1/2 (n=3/4), exclusively high TILs (n=2/9) and CDK12 (n=1/7). In responders, median duration of response was 4.9 months (range 1.8-19.7). Grade 3-4 treatment-related adverse events occurred in 17/35 (49%).

Conclusions: NIVO + IPI demonstrated significant activity in biomarker selected, pre-treated pts with mCRPC. The safety profile is consistent with this dosing schedule. Accrual to expansion cohort 2 started in September 2020.

Determinants of immunogenic signature in responding patientsPatientInflammatory Infiltrate (%)MMRD (Y/N)DDRD (Y/N)TMB Mut/MBNEP-03340NN1NEP-03610NY Biallelic BRCA24NEP-0964NY Biallelic BRCA28NEP-1093Y MSH2/MSH6N14NEP-12625Y MSH2/MSH6N21NEP-13110Y PMS2/MLH1N13NEP-15920Y MSH2/MSH6Y BRCA127NEP-16525NY Biallelic CDK125NEP-06930NN1

Citation Format: Mark D. Linch, Yien Ning Sophia Wong, Robert Jones, Peter Sankey, Debra H. Josephs, Simon J. Crabb, John Staffurth, Anjali Zarkar, Laura White, Marian Duggan, Giulia Pellizzari, Graham Wheeler, Sandy Beare, Hayley Cartwright, Josep Linares, Ayse Akarca, Sergio A. Quezada, Leah Ensell, John Hartley, Gerhardt Attard, Joanna Burr, Anuradha Jayaram, Bihani Kularatne, Mahaz Kayani, Moon Chung, Colin C. Pritchard, Alex Freeman, Aiman Haider, Teresa Marafioti. Nivolumab (NIVO) and ipilimumab (IPI) treatment in prostate cancer with an immunogenic signature: cohort 1 of the NEPTUNES multi-centre, two-stage biomarker-selected Phase II 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 LB004.

Prognostic Threshold for Circulating Tumor Cells in Patients With Pancreatic and Midgut Neuroendocrine Tumors

BACKGROUND

Circulating tumor cells (CTCs) are detectable in patients with neuroendocrine tumors (NETs) and are accurate prognostic markers although the optimum threshold has not been defined.

OBJECTIVE

This work aims to define optimal prognostic CTC thresholds in PanNET and midgut NETs.

PATIENTS AND METHODS

CellSearch was used to enumerate CTCs in 199 patients with metastatic pancreatic (PanNET) (90) or midgut NETs (109). Patients were followed for progression-free survival (PFS) and overall survival (OS) for a minimum of 3 years or until death.

RESULTS

The area under the receiver operating characteristic curve (AUROC) for progression at 12 months in PanNETs and midgut NETs identified the optimal CTC threshold as 1 or greater and 2 or greater, respectively. In multivariate logistic regression analysis, these thresholds were predictive for 12-month progression with an odds ratio (OR) of 6.69 (P < .01) for PanNETs and 5.88 (P < .003) for midgut NETs. The same thresholds were found to be optimal for predicting death at 36 months, with an OR of 2.87 (P < .03) and 5.09 (P < .005) for PanNETs and midgut NETs, respectively. In multivariate Cox hazard regression analysis for PFS in PanNETs, 1 or greater CTC had a hazard ratio (HR) of 2.6 (P < .01), whereas 2 or greater CTCs had an HR of 2.25 (P < .01) in midgut NETs. In multivariate analysis OS in PanNETs, 1 or greater CTCs had an HR of 3.16 (P < .01) and in midgut NETs, 2 or greater CTCs had an HR of 1.73 (P < .06).

CONCLUSIONS

The optimal CTC threshold to predict PFS and OS in metastatic PanNETs and midgut NETs is 1 and 2, respectively. These thresholds can be used to stratify patients in clinical practice and clinical trials.

Nivolumab and ipilimumab treatment in prostate cancer with an immunogenic signature (NEPTUNES)

TPS5090

Background: Responses to checkpoint inhibitor (CPI) monotherapy in patients with metastatic castration resistant prostate cancer (mCRPC) have been limited. This is in part attributed to low tumour mutational burden (TMB) and low tumour infiltrating lymphocytes (TILs). Previously ~20% patients with prostate cancer have demonstrated high TILs or TMB1. We hypothesize that patients with higher TMB due to mismatch repair deficiency (dMMR) or defective DNA damage response (dDDR) and patients with high TILs are more likely to respond to combination CPI with anti PD-1 and anti CTLA-4 therapy. Methods: NEPTUNES is a single arm phase II trial designed to assess the efficacy of nivolumab and ipilimumab in biomarker selected patients with mCRPC that have progressed following ≥1 line of therapy. The immunogenic signature (ImS) biomarker is defined by ≥1 of the following: 1) dMMR by immunohistochemistry (IHC); 2) dDDR detected by the UW-OncoPlex sequencing assay and; 3) high TILs on multiplexed IHC. The UW-OncoPlex assay detects mutations in >260 genes and provides an estimation of TMB. Assuming an ImS+ rate of 20%, we aim to pre-screen 175 patients in order to enrol 35 patients into the main study. The primary endpoint is composite response rate (CRR), achieved if ≥1 of the following criteria are satisfied: 1) radiological response by RECIST 1.1; 2) PSA response ≥50%; 3) conversion of circulating tumour cells (CTC) count from ≥5 cells at baseline to <5 cells at week 9. The treatment will be deemed ineffective if the CRR is <20%. Nivolumab (1 mg/kg) and ipilimumab (3 mg/kg) is dosed every three weeks for up to 4 times, followed by a 480mg flat dose of nivolumab every 4 weeks for up to one year. Baseline biopsies are mandated and paired biopsy at week 12 is encouraged. The secondary endpoints include safety, overall survival, and radiological and PSA progression free survival. Exploratory biological markers including TMB, mutational profiles, change in TILs and liquid biomarkers will be correlated with the primary clinical endpoint. Since opening in February 2018, 126 patients have been pre-screened with 25 ImS+. To date, 9/25 ImS+ patients have been enrolled into the main study. The trial is ongoing, with patient accrual expected to complete by late 2019. References: 1Linch, M., Goh, G., Hiley, C., Shanmugabavan, Y., McGranahan, N., Rowan, A., . . . Swanton, C. (2017). Intratumoural evolutionary landscape of high-risk prostate cancer: the PROGENY study of genomic and immune parameters. Ann Oncol, 28(10), 2472-2480. doi:10.1093/annonc/mdx355. Clinical trial information: NCT03061539.

EACH: A randomised phase II study evaluating the safety and anti-tumour activity of the combination of avelumab and cetuximab relative to avelumab monotherapy in recurrent/metastatic head and neck squamous cell cancer

TPS6091

Background: Patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) have low response rates to licensed second line therapies, including PD-1 inhibitors nivolumab and pembrolizumab, and represent an area of unmet clinical need. The chimeric IgG1 epithelial growth factor receptor (EGFR) monoclonal antibody cetuximab potentiates the activity of radiotherapy in locally advanced HNSCC and chemotherapy in R/M HNSCC and is also licensed with modest activity as a single agent. Cetuximab initiates Natural Killer (NK) cell antibody-dependent cell-mediated cytotoxicity (ADCC), resulting in an anti-tumour immune response and the potential to augment the activity of PD-1/PD-L1 inhibition. EACH aims to examine the safety and efficacy of the potentially synergistic interaction between cetuximab and avelumab, a fully human IgG1 anti-PD-L1 monoclonal antibody in R/M HNSCC. Methods: EACH is a randomised phase II trial preceded by a safety run-in phase. Eligible patients have histologically or cytologically confirmed measurable recurrent or metastatic squamous cell carcinoma of any site in the safety run-in phase, and HNSCC in phase II, that is considered incurable by local therapies. The safety run-in has a single arm de-escalating design, aiming to establish the safety of cetuximab with avelumab and determine the optimal dose of cetuximab within this combination. The safety run-in has a dosing schedule of avelumab (10 mg/kg) + cetuximab (500 mg/m2) intravenously every 2 weeks, with de-escalation of cetuximab to 400 mg/m2 and 300 mg/m2 if necessary. The safety run-in phase commenced recruitment in July 2018 and is ongoing. The phase II component will randomize 114 HNSCC patients between either avelumab + cetuximab at the dose determined by the safety run-in phase or avelumab (10 mg/kg) alone. Treatment will be in 4-week cycles for up to one year. The primary endpoint in the safety run-in phase is the occurrence of dose limiting toxicities, and in phase II is Disease Control Rate at 24 weeks, using iRECIST. Blood and fresh tissue will be collected for exploratory translational studies, which will focus on the identification of potential novel predictive biomarkers for response. Clinical trial information: NCT03494322.

Circulating tumour cells and their association with bone metastases in patients with neuroendocrine tumours

Background

Bone metastases are associated with a worse outcome in patients with neuroendocrine tumours (NETs). Tumour overexpression of C-X-C chemokine receptor 4 (CXCR4) appears predictive of skeletal involvement. We investigated the role of circulating tumour cells (CTCs) and CXCR4 expression on CTCs as potential predictors of skeleton invasion.

Methods

Blood from patients with metastatic bronchial, midgut or pancreatic NET (pNET) was analysed by CellSearch. CXCR4 immunohistochemistry was performed on matched formalin-fixed paraffin-embedded (FFPE) samples.

Results

Two hundred and fifty-four patients were recruited with 121 midgut and 119 pNETs, of which 51 and 36% had detectable CTCs, respectively. Bone metastases were reported in 30% of midgut and 23% of pNET patients and were significantly associated with CTC presence (p = 0.003 and p < 0.0001). In a subgroup of 40 patients, 85% patients with CTCs had CTCs positive for CXCR4 expression. The proportion of CXCR4-positive CTCs in patients with bone metastases was 56% compared to 35% in those without (p = 0.18) it. Staining for CXCR4 on matched FFPE tissue showed a trend towards a correlation with CXCR4 expression on CTCs (p = 0.08).

Conclusions

CTC presence is associated with bone metastases in NETs. CXCR4 may be involved in CTC osteotropism and present a therapeutic target to reduce skeletal morbidity.

Expression of somatostatin receptors 2 and 5 in circulating tumour cells from patients with neuroendocrine tumours

BACKGROUND

Neuroendocrine tumours (NET) overexpress somatostatin receptors (SSTR) that can be targeted for therapy. Somatostatin receptor expression is routinely measured by molecular imaging but the resolution is insufficient to define heterogeneity. We hypothesised that SSTR expression could be measured on circulating tumour cells (CTCs) and used to investigate heterogeneity of expression and track changes during therapy.

METHODS

MCF-7 cells were transfected with SSTR2 or 5 and spiked into donor blood for analysis by CellSearch. Optimum anti-SSTR antibody concentration and exposure time were determined, and flow cytometry was used to evaluate assay sensitivity. For clinical evaluation, blood was analysed by CellSearch, and SSTR2/5 immunohistochemistry was performed on matched tissue samples.

RESULTS

Flow cytometry confirmed CellSearch was sensitive and that detection of SSTR was unaffected by the presence of somatostatin analogue up to a concentration of 100 ng ml-l. Thirty-one NET patients were recruited: grade; G1 (29%), G2 (45%), G3 (13%), primary site; midgut (58%), pancreatic (39%). Overall, 87% had SSTR-positive tumours according to somatostatin receptor scintigraphy or 68-Ga-DOTATE PET/CT. Circulating tumour cells were detected in 21 out of 31 patients (68%), of which 33% had evidence of heterogeneous expression of either SSTR2 (n=5) or SSTR5 (n=2).

CONCLUSIONS

Somatostatin receptors 2 and 5 are detectable on CTCs from NET patients and may be a useful biomarker for evaluating SSTR-targeted therapies and this is being prospectively evaluated in the Phase IV CALMNET trial (NCT02075606).

Enumeration and Molecular Characterisation of Circulating Tumour Cells in Endometrial Cancer

BACKGROUND

This is a feasibility study to determine whether circulating tumour cells (CTCs) are detectable and suitable for molecular profiling in advanced endometrial cancer (aEC).

METHOD

Between October 2012 and February 2014, 30 patients with aEC had baseline and up to 3 follow-up samples. CTCs and stathmin expression were evaluated using the CellSearch platform. Epithelial cell adhesion molecule (EpCAM) and stathmin immunohistochemistry were performed on FFPE tumour tissue.

RESULTS

Eighteen from 30 (60%) patients had detectable CTCs during study [1 CTC (n = 7), 2 (n = 4), 3 (n = 1), 4 (n = 2), 7 (n = 1), 8 (n = 1), 22 (n = 1), 172 (n = 1) in 7.5 ml blood]. Ten from 18 patients had between 50 and 100% of detectable CTCs that were stathmin positive. More CTC-positive than CTC-negative patients had non-endometrioid versus endometrioid histology, tumour size ≥5 versus <5 cm, higher-stage disease and worse survival [hazard ratio 3.3, p > 0.05, 95% confidence interval 0.7-16.2]. Twenty-one tumour blocks were tested for EpCAM and stathmin immunohistochemistry (IHC). Stathmin tumour immunostaining scores (TIS) on IHC were higher in CTC-positive patients.

CONCLUSION

CTC enumeration and molecular profiling with stathmin on the CellSearch platform is feasible in aEC. Stathmin TIS on IHC, a known prognostic marker in EC, was associated with CTC positivity.

Abstract 5437: A novel method to quantify gamma H2AX foci in circulating tumor cells in patients receiving chemotherapy for colorectal cancer

Phosphorylated H2AX (γH2AX) is a marker of DNA double-strand break damage and has been proposed as a pharmacodynamic biomarker following treatment with chemotherapy. γH2AX levels in circulating tumor cells (CTCs) may provide a sensitive direct marker for assessing drug effects in tumor tissue without the need for biopsy. In the present study, we established a novel assay to quantify changes in γH2AX in CTCs from patients with metastatic colorectal cancers undergoing treatment with Fulfox or Folfiri. γH2AX foci were initially assessed in human colon adenocarcinoma cancer cell lines (HT-29) treated with different concentrations of Oxaliplatin and SN-38 at different time points. Image capture was conducted using Confocal Microscope Leica SPE2 and γH2AX foci were analyzed with CellProfiler software. The highest number of γH2AX foci/nucleus was induced at 5uM for Oxaliplatin and 0.01uM for SN-38 and the peak of γH2AX foci/nucleus was observed between two-six hours post dose. To reproduce the analytical process for CTCs, we evaluated the γH2AX signal using both the CellSearch System (Janssen Diagnostics) and the DEPArray™ System (Silicon Biosystems). HT-29 cells were used, either as untreated controls or following 2 hours treatment with Oxaliplatin 5uM or SN-38 0.01uM and spiked in to healthy donor blood. Cells were defined as positive for γH2AX on the CellSearch according to a previously validated assay. For Oxaliplatin and SN-38 treated cells, 15.28% and 18.37% respectively were classified as positive for γH2AX, compared with 5.10% for untreated controls. However, using CellSearch, the fluorescent signal could not be quantified and we therefore repeated the experiment using the DEPArray platform. HT-29 cells were treated with SN-38 as above, and compared with an untreated control group using two different exposure times for fluorescein isothiocyanate-conjugated antibody (FITC): FITCI (100 ms and gain 1X) and FITCII (800 ms and gain 4X). The treated group showed a significantly increased intensity of FITC staining compared with the untreated control group: mean 363 vs mean 220 (p&lt;0.0001) for FITCI, and mean 5521 vs mean 4365 (p&lt;0.0040) for FITCII. The DEPArray system therefore has an advantage in being able to quantify differences in signal intensity caused by induction of γH2AX in CTCs and then select individual cells for further downstream analysis. This analysis is now being applied to patient samples collected pre and post-chemotherapy to evaluate the utility of the assay in a clinical setting.

Citation Format: Matilde Saggese, Leah Ensell, Clare Vesely, Victoria Spanswick, Elena Peruzzi, Diana Cunati, Giulio Signorini, John Hartley, Hendrik Tobias Arkenau, Tim Meyer. A novel method to quantify gamma H2AX foci in circulating tumor cells in patients receiving chemotherapy for colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5437. doi:10.1158/1538-7445.AM2015-5437