A phase II study of daily encorafenib in combination with biweekly cetuximab in patients with BRAF V600E mutated metastatic colorectal cancer: the NEW BEACON study.

BACKGROUND: Patients with BRAF V600E mutated metastatic colorectal cancer (mCRC) have a poor prognosis. The introduction of BRAF targeted therapy with encorafenib and weekly administered cetuximab have shown improved survival with a median progression free survival (PFS) of 4.3 months. However, a regimen with cetuximab given every second week may have comparable efficacy and is more convenient for patients. While BRAF targeted therapy is a new standard therapy in pre-treated patients with BRAF V600E mutated mCRC, resistance invariably occurs and is an emerging challenge. The aim of this study is to investigate the efficacy and tolerability of cetuximab given every second week in combination with daily encorafenib and to explore the correlation between markers of resistance and outcome. METHODS: The study is an open label, single arm, phase II study, investigating the efficacy and tolerability of cetuximab given every second week in combination with encorafenib in patients with BRAF V600E mutated mCRC. Furthermore, we will be investigating mechanisms of response and resistance against BRAF targeted therapy though comprehensive genomic profiling on tumor tissue and blood for circulating tumor DNA analysis. A total of 53 patients (19 + 34 in two steps) will be included according to Simon's optimal two stage design. The primary end point of the study is 2 months PFS rate. DISCUSSION: By combining BRAF inhibitor with cetuximab given every second week we can halve the number of visits in the hospital compared to the currently approved regimen with weekly cetuximab. This seems particularly relevant in a group of patients with a median overall survival of 9.3 months. Resistance after initial response to targeted therapy can be either adaptive (e.g., epigenetic, or transcriptomic alterations) or acquired (selective genetic alterations - e.g., activating de novo mutations) resistance. It is of great importance to untangle these complex mechanisms of resistance in patients with BRAF V600E mutated mCRC to improve treatment strategies in the future potentially even further. TRIAL REGISTRATION: EU Clinical Trial Register, Eudract no. 2020-003283-10 . Registered on 11 November 2020.

Similar genetic profile in early and late stage urothelial tract cancer.

INTRODUCTION: Urothelial tract cancer (UTC) ranks as the tenth most prevalent cancer and holds the seventh position in terms of mortality worldwide. Despite its prevalence and mortality ranking, there are still gaps in the knowledge of the mutational landscape in patients with advanced disease who have limited therapeutic options after multiple lines of prior treatment. This study compares the genomic and transcriptomic landscape, and targeted treatment options between metastatic UTC (mUTC) patients treated with multiple lines of therapy compared to newly diagnosed, untreated Muscle Invasive Bladder Cancer (MIBC). METHODS: We compared genomic and clinical data from two cohorts: mUTC patients who received multiple lines of therapy and were referred to the Copenhagen Prospective Personalized Oncology (CoPPO) project at Rigshospitalet, University of Copenhagen. Data for MIBC UTC patients were acquired from the Cancer Genome Atlas Bladder Cancer (TCGA BLCA) cohort. Biopsies in CoPPO were performed at the time of enrollment. 523 highly important cancer-related genes (TrueSight Oncology-500 targeted sequencing panel) were used from both cohorts for comparative analysis. Analyses included RNA count data to compare predicted molecular subtypes in each cohort separately. RESULTS: Patients from the CoPPO cohort had a lower median age at first-line treatment than the TCGA BLCA cohort, with no significant gender disparity. The predominant histology was urothelial cell carcinoma in both cohorts. Genomic analysis revealed no significant difference between the top mutated genes in the two cohorts, specifically looking into DNA damage repair genes. Molecular subtyping indicated a higher frequency of neuroendocrine differentiation in the CoPPO cohort. 13% of patients in the CoPPO cohort received targeted therapy based on genomic findings, and 16% received non-targeted treatment, totaling 29% receiving CoPPO treatment (9 patients). The remaining 71% received best supportive care. Kaplan-Meier analysis showed a non-significant survival benefit for the intervention group in the CoPPO cohort. CONCLUSION: When focusing on 523 highly relevant cancer genes, the mutational profile of mUTC patients who have undergone numerous treatment lines resembles that of newly diagnosed MIBC. These alterations can be targeted, indicating the potential advantage of early genomic testing for personalized treatment within clinical trials.

Cytokine release syndrome caused by antineoplastic treatment with CAR-T and T-cell engaging therapies.

T-cell-based immunotherapy has recently evolved as a treatment option for a number of haematological malignancies and is also being developed in solid tumours. A common side effect of chimeric antigen T-cell therapy (CAR-T) and treatment with T-cell engagers is cytokine release syndrome (CRS), which is a potentially life-threatening condition characterized by release of inflammatory mediators. The treatment of CRS is similar to that of other hyper-inflammatory conditions and involves supportive treatment as well as immunosuppressive therapy. The risk of CRS can be mitigated by step-up dosing and immunosuppressive pre-treatment, as argued in this review.

Thiopurine 6TG treatment increases tumor immunogenicity and response to immune checkpoint blockade.

Immune-checkpoint inhibitors (ICI) are highly effective in reinvigorating T cells to attack cancer. Nevertheless, a large subset of patients fails to benefit from ICI, partly due to lack of the cancer neoepitopes necessary to trigger an immune response. In this study, we used the thiopurine 6-thioguanine (6TG) to induce random mutations and thus increase the level of neoepitopes presented by tumor cells. Thiopurines are prodrugs which are converted into thioguanine nucleotides that are incorporated into DNA (DNA-TG), where they can induce mutation through single nucleotide mismatching. In a pre-clinical mouse model of a mutation-low melanoma cell line, we demonstrated that 6TG induced clinical-grade DNA-TG integration resulting in an improved tumor control that was strongly T cell dependent. 6TG exposure increased the tumor mutational burden, without affecting tumor cell proliferation and cell death. Moreover, 6TG treatment re-shaped the tumor microenvironment by increasing T and NK immune cells, making the tumors more responsive to immune-checkpoint blockade. We further validated that 6TG exposure improved tumor control in additional mouse models of melanoma. These findings have paved the way for a phase I/II clinical trial that explores whether treatment with thiopurines can increase the proportion of otherwise treatment-resistant cancer patients who may benefit from ICI therapy (NCT05276284).

Differences in gene expression despite identical histomorphology in sinonasal intestinal-type adenocarcinoma and metastases from colorectal adenocarcinoma.

Sinonasal intestinal-type adenocarcinoma (sITAC) is histomorphologically indistinguishable from colorectal adenocarcinoma (CRC) leading to diagnostic challenges. Metastases from CRCs to the sinonasal tract have been reported. The aim of the study was to identify a biomarker making it possible to distinguish between sITAC and metastases of colorectal origin. Formalin-fixated paraffin-embedded (FFPE) tissue from 20 consecutive patients with sITAC treated at Rigshospitalet, Denmark from 2005 to 2017, 20 patients with CRC, and second patients with both sinonasal and colorectal carcinomas were included, and RNA-sequencing was performed on all samples. Moreover, a series of 26 samples from metastasizing CRC were included (in-house data). 3139 differentially expressed genes were identified, of these several were deemed as possible biomarkers, including CSDE1, for which immunohistochemical staining was performed. sITAC and CRC differ in genomic expression. CSDE1, previously found upregulated in CRC, was significantly differentially expressed. Using immunohistochemical staining, no sITACs displayed strong and diffuse staining for CSDE1, which represents a potential marker to use in distinguishing sITAC from a metastasis of colorectal origin. This knowledge could improve the diagnostic process and hopefully the outcome in patients with this rare tumor.

[Trends in oncological phase I trials].

This review summarises the current knowledge of anticancer therapy. More than 1,100 cancer drugs are currently under development in the United States. The increasing biological insight and platforms for high throughput screening of drugs have changed the developmental landscape of anticancer therapies from classical cytotoxic agents to targeted agents and immunotherapy. There is an increasing number of targeted agents, which are only efficacious in tumours harbouring specific genomic alterations in early clinical development. Furthermore, the landscape of immunotherapy broadens, and personalised immunotherapy is in development. The integration of genomic testing into early clinical oncology trials is increasing.

Copenhagen Prospective Personalized Oncology (CoPPO)-Clinical Utility of Using Molecular Profiling to Select Patients to Phase I Trials.

PURPOSE: We evaluated the clinical benefit of tumor molecular profiling to select treatment in the phase I setting. EXPERIMENTAL DESIGN: Patients with advanced solid cancers and exhausted treatment options referred to a phase I unit were included in a prospective, single-center, single-arm open-label study (NCT02290522). Tumor biopsies were obtained for comprehensive genomic analysis including whole-exome sequencing and RNA sequencing. When possible, patients were treated with regimen matched to the genomic profile. Primary endpoint was progression-free survival (PFS). RESULTS: From May 2013 to January 2017, a total of 591 patients were enrolled, with 500 patients undergoing biopsy. Genomic profiles were obtained in 460 patients and a potential actionable target was identified in 352 (70%) of 500 biopsied patients. A total of 101 patients (20%) received matched treatment based on either gene mutations or RNA expression levels of targets available in early clinical trials or off-label treatment. Objective response according to RECIST1.1 was observed in 15 of 101 patients (0% complete response, 15% partial response), with a median PFS of 12 weeks (95% confidence interval, 9.9-14.4). CONCLUSIONS: Our study supports the feasibility of genomic profiling to select patients in the phase I setting and suggests that genomic matching can be beneficial for a minor subset of patients with no other treatment options. Randomized studies may validate this assumption.See related commentary by Ratain, p. 1136.

Circulating tumor DNA as a marker of treatment response in BRAF V600E mutated non-melanoma solid tumors.

PURPOSE: We evaluated longitudinal tracking of BRAF V600E in circulating cell-free DNA (cfDNA) as a marker of treatment response to BRAF inhibitor (BRAFi) combination therapies in non-melanoma solid tumors included in the Copenhagen Prospective Personalized Oncology (CoPPO) program. EXPERIMENTAL DESIGN: Patients with BRAF V600E-mutated tumors were treated with combination therapies including BRAFi. Quantification of mutant cfDNA from plasma was determined and correlated to clinical outcomes. Exome sequencing was performed to identify possible resistance mutations. RESULTS: Twenty-three patients had BRAF-mutated tumors out of 455 patients included in CoPPO and 17 started BRAFi combination (EGFRi/MEKi) therapy. Tumor responses were achieved in 8 out of 16 evaluable patients and the median overall- and progression-free survival (OS and PFS) was 15 and 4.8 months, respectively. Longitudinal measurements of BRAF V600E-mutant cfDNA indicated disease progression prior to radiological evaluation and a reduction in the mutant fraction of more than 50% after 4 and 12 weeks of therapy was associated with a significantly longer PFS (p=0.003 and p=0.029) and OS (p=0.029 and p=0.017). Furthermore, the baseline mutant fraction and total level of cfDNA positively correlated with tumor burden (p=0.026 and p=0.024). Finally, analysis of cfDNA at progression revealed novel mutations potentially affecting the MAPK pathway. CONCLUSION: BRAFi combination therapies showed a response rate of 50% in BRAF V600E-mutated non-melanoma tumors. The fraction of BRAF-mutant cfDNA represent a sensitive indicator for clinical outcomes with plasma collected at week 4 and 12 as crucial time points for monitoring response and disease progression.

Biomarkers in tissue from patients with upper gastrointestinal cancers treated with erlotinib and bevacizumab.

Malignancies in the upper gastrointestinal (UGI) tract are amongst the most aggressive cancers and only few treatment options exist. We have recently analysed data from a phase II trial where patients with UGI cancers were treated with erlotinib and bevacizumab. The combination therapy could not be recommended in an unselected population of patients with chemo-refractory UGI cancer. However, a subpopulation of patients did benefit from the therapy. In this prospectively planned biomarker study we investigated vascular endothelial growth factor A (VEGF-A), VEGF receptor 2 (VEGFR-2) and epidermal growth factor receptor (EGFR) by immunohistochemistry and KRAS mutation status detected by PCR as potential predictors of effect of therapy. High VEGF-A expression was correlated to longer overall survival (HR: 0.8, 95%CI: 0.7-0.9) and high VEGFR-2 expression to shorter progression free survival (HR: 1.4, 95%CI: 1.0-1.9). EGFR expression and KRAS mutation status were not correlated to response or survival. We conclude that VEGF-A and VEGFR-2 could potentially be predictive markers in patients with UGI cancers treated with erlotinib and bevacizumab.

Markers of angiogenesis and epidermal growth factor receptor signalling in patients with pancreatic and gastroesophageal junction cancer.

The epidermal growth factor receptor (EGFR) and angiogenesis are well established targets in anti-cancer therapy. Several targeted anti-cancer therapies are in clinical trials in pancreatic and gastroesophageal (GEJ) cancer. However, many patients do not respond to these targeted therapies and there is therefore an increasing need for biomarkers for selection of patients to these therapies. We investigated the expression of EGFR, vascular endothelial growth factor A (VEGF-A), and VEGF receptor 2 (VEGFR-2) in tumour tissue by immunohistochemistry, and soluble EGFR (sEGFR), soluble VEGFR-2 (sVEGFR-2), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), plasminogen activator inhibitor 1 (PAI-1), and different forms of the urokinase plasminogen activator receptor (uPAR): uPAR (I), uPAR (I-III), and uPAR (I-III)+(II-III) in plasma by quantitative immunoassays in 14 patients with pancreatic and GEJ cancer. We found expression in tumour tissue and the plasma levels to be similar to those found in patients with other tumour types. No correlation was found between the blood levels of soluble receptors and the corresponding tumour tissue levels. We conclude that these markers are present in pancreatic and GEJ cancer patients, and could be investigated further as predictive biomarkers in such patients treated with EGFR or angiogenesis targeted therapies.