Dietary fibre supplementation enhances radiotherapy tumour control and alleviates intestinal radiation toxicity.

BACKGROUND: Non-toxic approaches to enhance radiotherapy outcomes are beneficial, particularly in ageing populations. Based on preclinical findings showing that high-fibre diets sensitised bladder tumours to irradiation by modifying the gut microbiota, along with clinical evidence of prebiotics enhancing anti-cancer immunity, we hypothesised that dietary fibre and its gut microbiota modification can radiosensitise tumours via secretion of metabolites and/or immunomodulation. We investigated the efficacy of high-fibre diets combined with irradiation in immunoproficient C57BL/6 mice bearing bladder cancer flank allografts. RESULT: Psyllium plus inulin significantly decreased tumour size and delayed tumour growth following irradiation compared to 0.2% cellulose and raised intratumoural CD8+ cells. Post-irradiation, tumour control positively correlated with Lachnospiraceae family abundance. Psyllium plus resistant starch radiosensitised the tumours, positively correlating with Bacteroides genus abundance and increased caecal isoferulic acid levels, associated with a favourable response in terms of tumour control. Psyllium plus inulin mitigated the acute radiation injury caused by 14 Gy. Psyllium plus inulin increased caecal acetate, butyrate and propionate levels, and psyllium alone and psyllium plus resistant starch increased acetate levels. Human gut microbiota profiles at the phylum level were generally more like mouse 0.2% cellulose profiles than high fibre profiles. CONCLUSION: These supplements may be useful in combination with radiotherapy in patients with pelvic malignancy. Video Abstract.

Image-based consensus molecular subtyping in rectal cancer biopsies and response to neoadjuvant chemoradiotherapy.

The development of deep learning (DL) models to predict the consensus molecular subtypes (CMS) from histopathology images (imCMS) is a promising and cost-effective strategy to support patient stratification. Here, we investigate whether imCMS calls generated from whole slide histopathology images (WSIs) of rectal cancer (RC) pre-treatment biopsies are associated with pathological complete response (pCR) to neoadjuvant long course chemoradiotherapy (LCRT) with single agent fluoropyrimidine. DL models were trained to classify WSIs of colorectal cancers stained with hematoxylin and eosin into one of the four CMS classes using a multi-centric dataset of resection and biopsy specimens (n = 1057 WSIs) with paired transcriptional data. Classifiers were tested on a held out RC biopsy cohort (ARISTOTLE) and correlated with pCR to LCRT in an independent dataset merging two RC cohorts (ARISTOTLE, n = 114 and SALZBURG, n = 55 patients). DL models predicted CMS with high classification performance in multiple comparative analyses. In the independent cohorts (ARISTOTLE, SALZBURG), cases with WSIs classified as imCMS1 had a significantly higher likelihood of achieving pCR (OR = 2.69, 95% CI 1.01-7.17, p = 0.048). Conversely, imCMS4 was associated with lack of pCR (OR = 0.25, 95% CI 0.07-0.88, p = 0.031). Classification maps demonstrated pathologist-interpretable associations with high stromal content in imCMS4 cases, associated with poor outcome. No significant association was found in imCMS2 or imCMS3. imCMS classification of pre-treatment biopsies is a fast and inexpensive solution to identify patient groups that could benefit from neoadjuvant LCRT. The significant associations between imCMS1/imCMS4 with pCR suggest the existence of predictive morphological features that could enhance standard pathological assessment.

The impact of travel time to cancer treatment centre on post-diagnosis care and mortality among cancer patients in Scotland.

Limited data exist on the effect of travelling time on post-diagnosis cancer care and mortality. We analysed the impact of travel time to cancer treatment centre on secondary care contact time and one-year mortality using a data-linkage study in Scotland with 17369 patients. Patients with longer travelling time and island-dwellers had increased incidence rate of secondary care cancer contact time. For outpatient oncology appointments, the incidence rate was decreased for island-dwellers. Longer travelling time was not associated with increased secondary care contact time for emergency cancer admissions or time to first emergency cancer admission. Living on an island increased mortality at one-year. Adjusting for cancer-specific secondary care contact time increased the hazard of death, and adjusting for oncology outpatient time decreased the hazard of death for island-dwellers. Those with longer travelling times experience the cancer treatment pathway differently with poorer outcomes. Cancer services may need to be better configured to suit differing needs of dispersed populations.

Experiences of running a stratified medicine adaptive platform trial: Challenges and lessons learned from 10 years of the FOCUS4 trial in metastatic colorectal cancer.

BACKGROUND: Complex innovative design trials are becoming increasingly common and offer potential for improving patient outcomes in a faster time frame. FOCUS4 was the first molecularly stratified trial in metastatic colorectal cancer and it remains one of the first umbrella trial designs to be launched globally. Here, we aim to describe lessons learned from delivery of the trial over the last 10 years. METHODS: FOCUS4 was a Phase II/III molecularly stratified umbrella trial testing the safety and efficacy of targeted therapies in metastatic colorectal cancer. It used adaptive statistical methodology to decide which sub-trial should close early, and new therapies were added as protocol amendments. Patients with newly diagnosed metastatic colorectal cancer were registered, and central laboratory testing was used to stratify their tumour into molecular subtypes. Following 16 weeks of first-line therapy, patients with stable or responding disease were eligible for randomisation into either a molecularly stratified sub-trial (FOCUS4-B, C or D) or non-stratified FOCUS4-N. The primary outcome for all studies was progression-free survival comparing the intervention with active monitoring/placebo. At the close of the trial, feedback was elicited from all investigators through surveys and interviews and consolidated into a series of recommendations and lessons learned for the delivery of similar future trials. RESULTS: Between January 2014 and October 2020, 1434 patients were registered from 88 UK hospitals. Of the 20 drug combinations that were explored for inclusion in the platform trial, three molecularly targeted sub-trials were activated: FOCUS4-D (February 2014-March 2016) evaluated AZD8931 in the BRAF-PIK3CA-RAS wildtype subgroup; FOCUS4-B (February 2016-July 2018) evaluated aspirin in the PIK3CA mutant subgroup and FOCUS4-C (June 2017-October 2020) evaluated adavosertib in the RAS+TP53 double mutant subgroup. FOCUS4-N was active throughout and evaluated capecitabine monotherapy versus a treatment break. A total of 361 (25%) registered patients were randomised into a sub-trial. Feedback on the experiences of delivery of FOCUS4 could be grouped into three main areas of challenge: funding/infrastructure, biomarker testing procedures and trial design efficiencies within which 20 recommendations are summarised. CONCLUSION: Adaptive stratified medicine platform studies are feasible in common cancers but present challenges. Our stakeholder feedback has helped to inform how these trial designs can succeed and answer multiple questions efficiently, providing resource is adequate.

Oral antibiotic use and early-onset colorectal cancer: findings from a case-control study using a national clinical database.

BACKGROUND: Antibiotic-induced gut dysbiosis has been associated with colorectal cancer (CRC) in older adults. This study will investigate whether an association exists between antibiotic usage and early-onset colorectal cancer (CRC), and also evaluate this in later-onset CRC for comparison. METHODS: A case-control study was conducted using primary care data from 1999-2011. Analysis were conducted separately in early-onset CRC cases (diagnosed < 50 years) and later-onset cases (diagnosed ≥ 50 years). Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (CI) for the associations between antibiotic exposure and CRC by tumour location, adjusting for comorbidities. RESULTS: Seven thousands nine hundred and three CRC cases (445 aged <50 years) and 30,418 controls were identified. Antibiotic consumption was associated with colon cancer in both age-groups, particularly in the early-onset CRC cohort (<50 years: adjusted Odds Ratio (ORadj) 1.49 (95% CI 1.07, 2.07), p = 0·018; ≥50 years (ORadj (95% CI) 1.09 (1.01, 1.18), p = 0·029). Antibiotics were not associated with rectal cancer (<50 years: ORadj (95% CI) 1.17 (0.75, 1.84), p = 0.493; ≥50 years: ORadj (95% CI) 1.07 (0.96, 1.19), p = 0.238). CONCLUSION: Our findings suggest antibiotics may have a role in colon tumour formation across all age-groups.

Capecitabine Versus Active Monitoring in Stable or Responding Metastatic Colorectal Cancer After 16 Weeks of First-Line Therapy: Results of the Randomized FOCUS4-N Trial.

PURPOSE: Despite extensive randomized evidence supporting the use of treatment breaks in metastatic colorectal cancer (mCRC), they are not universally offered to patients despite improvements in quality of life without detriment to overall survival (OS). FOCUS4-N was set up to explore the impact of oral maintenance therapy in patients who are responding to first-line therapy. METHODS: FOCUS4 was a molecularly stratified trial program that registered patients with newly diagnosed mCRC. The FOCUS4-N trial was offered to patients in whom a targeted subtrial was unavailable or biomarker tests failed. Patients were randomly assigned using a 1:1 ratio between maintenance capecitabine and active monitoring (AM). The primary outcome was progression-free survival (PFS) with secondary outcomes including OS toxicity and tolerability. RESULTS: Between March 2014 and March 2020, 254 patients were randomly assigned (127 to capecitabine and 127 to AM) across 88 UK sites. Baseline characteristics were balanced. There was strong evidence of efficacy for PFS (hazard ratio = 0.40; 95% CI, 0.21 to 0.75; P < .0001), but no significant improvement in OS (hazard ratio, 0.93; 95% CI, 0.69 to 1.27; P = .66) was observed. Compliance with treatment was good, and toxicity from capecitabine versus AM was as expected with grade ≥ 2 fatigue (25% v 12%), diarrhea (23% v 13%), and hand-foot syndrome (26% v 3%). Quality of life showed little difference between the groups. CONCLUSION: Despite strong evidence of disease control with maintenance therapy, OS remains unaffected and FOCUS4-N provides additional evidence to support the use of treatment breaks as safe management alternatives for patients who are stable or responding to first-line treatment for mCRC. Capecitabine without bevacizumab may be used to extend PFS in the interval after 16 weeks of first-line therapy.

Durvalumab (MEDI 4736) in combination with extended neoadjuvant regimens in rectal cancer: a study protocol of a randomised phase II trial (PRIME-RT).

BACKGROUND: Advances in multi-modality treatment of locally advanced rectal cancer (LARC) have resulted in low local recurrence rates, but around 30% of patients will still die from distant metastatic disease. In parallel, there is increasing recognition that with radiotherapy and systemic treatment, some patients achieve a complete response and may avoid surgical resection, including in many cases, the need for a permanent stoma. Extended neoadjuvant regimes have emerged to address these concerns. The inclusion of immunotherapy in the neoadjuvant setting has the potential to further enhance this strategy by priming the local immune microenvironment and engaging the systemic immune response. METHODS: PRIME-RT is a multi-centre, open label, phase II, randomised trial for patients with newly diagnosed LARC. Eligible patients will be randomised to receive either: short course radiotherapy (25 Gray in 5 fractions over one week) with concomitant durvalumab (1500 mg administered intravenously every 4 weeks), followed by FOLFOX (85 mg/m2 oxaliplatin, 350 mg folinic acid and 400 mg/m2 bolus 5-fluorouracil (5-FU) given on day 1 followed by 2400 mg/m2 5-FU infusion over 46-48 h, all administered intravenously every 2 weeks), and durvalumab, or long course chemoradiotherapy (50 Gray to primary tumour in 25 fractions over 5 weeks with concomitant oral capecitabine 825 mg/m2 twice per day on days of radiotherapy) with durvalumab followed by FOLFOX and durvalumab. The primary endpoint is complete response rate in each arm. Secondary endpoints include treatment compliance, toxicity, safety, overall recurrence, proportion of patients with a permanent stoma, and survival. The study is translationally rich with collection of bio-specimens prior to, during, and following treatment in order to understand the molecular and immunological factors underpinning treatment response. The trial opened and the first patient was recruited in January 2021. The main trial will recruit up to 42 patients with LARC and commence after completion of a safety run-in that will recruit at least six patients with LARC or metastatic disease. DISCUSSION: PRIME-RT will explore if adding immunotherapy to neoadjuvant radiotherapy and chemotherapy for patients with LARC can prime the tumour microenvironment to improve complete response rates and stoma free survival. Sequential biopsies are a key component within the trial design that will provide new knowledge on how the tumour microenvironment changes at different time-points in response to multi-modality treatment. This expectation is that the trial will provide information to test this treatment within a large phase clinical trial. Trial registration Clinicaltrials.gov NCT04621370 (Registered 9th Nov 2020) EudraCT number 2019-001471-36 (Registered 6th Nov 2020).

Pathological response post neoadjuvant therapy for locally advanced rectal cancer is an independent predictor of survival.

AIM: Neoadjuvant treatment (NaT) for locally advanced rectal cancer prior to surgery has led to improved outcomes. However, the relationship between pathological response to NaT and survival is not entirely clear. The aim of this study was to assess the degree of pathological response to NaT on survival outcomes. METHODS: Clinical and pathological data were collected from a prospectively maintained pathology database between 2005 and 2017. The primary outcome was the overall survival based on pathological response categorized as complete, good partial, partial and minimal. Univariate and multivariate analyses were conducted to identify variables predictive of survival. Cox proportional hazard ratios were used for survival. RESULTS: A total of 596 patients had surgery following NaT for locally advanced rectal cancer. The median follow-up was 4.57 years (interquartile range 2.21-8.15 years). The overall survival for complete pathological response was 75.6% vs. 37.3% for minimal response (P < 0.001). The overall survival at the end of the study in the good partial vs. partial response groups was 58.9% vs. 39% (P < 0.001). On multivariate analysis, the degree of pathological response remains an independent variable for overall and disease-specific survival across all categories. DISCUSSION: In addition to other pathological variables, the degree of pathological response to NaT is an independent predictor for survival outcomes. Future verification of these findings elsewhere could support NaT response being used for adjuvant therapy decision making.

Image-based consensus molecular subtype (imCMS) classification of colorectal cancer using deep learning.

OBJECTIVE: Complex phenotypes captured on histological slides represent the biological processes at play in individual cancers, but the link to underlying molecular classification has not been clarified or systematised. In colorectal cancer (CRC), histological grading is a poor predictor of disease progression, and consensus molecular subtypes (CMSs) cannot be distinguished without gene expression profiling. We hypothesise that image analysis is a cost-effective tool to associate complex features of tissue organisation with molecular and outcome data and to resolve unclassifiable or heterogeneous cases. In this study, we present an image-based approach to predict CRC CMS from standard H&E sections using deep learning. DESIGN: Training and evaluation of a neural network were performed using a total of n=1206 tissue sections with comprehensive multi-omic data from three independent datasets (training on FOCUS trial, n=278 patients; test on rectal cancer biopsies, GRAMPIAN cohort, n=144 patients; and The Cancer Genome Atlas (TCGA), n=430 patients). Ground truth CMS calls were ascertained by matching random forest and single sample predictions from CMS classifier. RESULTS: Image-based CMS (imCMS) accurately classified slides in unseen datasets from TCGA (n=431 slides, AUC)=0.84) and rectal cancer biopsies (n=265 slides, AUC=0.85). imCMS spatially resolved intratumoural heterogeneity and provided secondary calls correlating with bioinformatic prediction from molecular data. imCMS classified samples previously unclassifiable by RNA expression profiling, reproduced the expected correlations with genomic and epigenetic alterations and showed similar prognostic associations as transcriptomic CMS. CONCLUSION: This study shows that a prediction of RNA expression classifiers can be made from H&E images, opening the door to simple, cheap and reliable biological stratification within routine workflows.

The McCAVE Trial: Vanucizumab plus mFOLFOX-6 Versus Bevacizumab plus mFOLFOX-6 in Patients with Previously Untreated Metastatic Colorectal Carcinoma (mCRC).

BACKGROUND: Bevacizumab, a VEGF-A inhibitor, in combination with chemotherapy, has proven to increase progression-free survival (PFS) and overall survival in multiple lines of therapy of metastatic colorectal cancer (mCRC). The angiogenic factor angiopoetin-2 (Ang-2) is associated with poor prognosis in many cancers, including mCRC. Preclinical models demonstrate improved activity when inhibiting both VEGF-A and Ang-2, suggesting that the dual VEGF-A and Ang-2 blocker vanucizumab (RO5520985 or RG-7221) may improve clinical outcomes. This phase II trial evaluated the efficacy of vanucizumab plus modified (m)FOLFOX-6 (folinic acid (leucovorin), fluorouracil (5-FU) and oxaliplatin) versus bevacizumab/mFOLFOX-6 for first-line mCRC. PATIENTS AND METHODS: All patients received mFOLFOX-6 and were randomized 1:1 to also receive vanucizumab 2,000 mg or bevacizumab 5 mg/kg every other week. Oxaliplatin was given for eight cycles; other agents were continued until disease progression or unacceptable toxicity for a maximum of 24 months. The primary endpoint was investigator-assessed PFS. RESULTS: One hundred eighty-nine patients were randomized (vanucizumab, n = 94; bevacizumab, n = 95). The number of PFS events was comparable (vanucizumab, n = 39; bevacizumab, n = 43). The hazard ratio was 1.00 (95% confidence interval, 0.64-1.58; p = .98) in a stratified analysis based on number of metastatic sites and region. Objective response rate was 52.1% and 57.9% in the vanucizumab and bevacizumab arm, respectively. Baseline plasma Ang-2 levels were prognostic in both arms but not predictive for treatment effects on PFS of vanucizumab. The incidence of adverse events of grade ≥3 was similar between treatment arms (83.9% vs. 82.1%); gastrointestinal perforations (10.8% vs. 8.4%) exceeded previously reported rates in this setting. Hypertension and peripheral edema were more frequent in the vanucizumab arm. CONCLUSION: Vanucizumab/mFOLFOX-6 did not improve PFS and was associated with increased rates of antiangiogenic toxicity compared with bevacizumab/mFOLFOX-6. Our results suggest that Ang-2 is not a relevant therapeutic target in first-line mCRC. IMPLICATIONS FOR PRACTICE: This randomized phase II study demonstrates that additional angiopoietin-2 (Ang-2) inhibition does not result in superior benefit over anti-VEGF-A blockade alone when each added to standard chemotherapy. Moreover, the performed pharmacokinetic and pharmacodynamic analysis revealed that vanucizumab was bioavailable and affected its intended target, thereby strongly suggesting that Ang-2 is not a relevant therapeutic target in the clinical setting of treatment-naïve metastatic colorectal cancer. As a result, the further clinical development of the dual VEGF-A and Ang-2 inhibitor vanucizumab was discontinued.

Young-onset colorectal cancer in the North East of Scotland: survival, clinico-pathological features and genetics.

BACKGROUND: Colorectal cancer (CRC) in patients aged under 55 years is on the rise, constituting approximately 10% of cases. Our aim was to determine the survival and clinico-pathological details of young-onset CRC (yCRC), as well as audit the referral rate to genetic services and thus establish the incidence of inherited cancer syndromes. METHODS: A retrospective case note review was conducted for patients aged under 55 years who were diagnosed with CRC between 2005 and 2015 in the North East of Scotland. Cases were identified by pathology records and data was obtained from patient notes. Analysis was performed using SPSS version 25 (IBM, New York, USA) to produce Kaplan-Meier survival estimates, descriptive statistics and markers predictive for genetic referral. RESULTS: Data from 345 patients (age range 22-54 years) were identified. The one year, five year and overall survival rates were found to be 89, 63 and 55%, respectively. Most patients (61%) presented with advanced disease. Of 201 patients that met criteria for genetic referral, only 93 (46%) were referred to genetic services. Microsatellite instability (MSI) was identified in 14% of those referred. CONCLUSION: Survival in yCRC was found to be better than that in later onset disease, despite higher rates of advanced disease. Patients were under-referred to genetic services, where a significant proportion were found to be MSI positive and investigated for Lynch syndrome.

Case Report: Management of an Elderly Patient With Metastatic Radioiodine-Resistant Differentiated Thyroid Cancer in a Rural Community, Remote From Specialist Oncology Services.

This case report describes an elderly patient with radioiodine-resistant differentiated thyroid cancer and additional multiple metastases living in a rural setting, remote from the specialist oncology service. This case is of interest because effective systemic therapies for treatment-resistant cancers, such as lenvatinib, are now available but can potentially cause significant toxicities that require extensive medical management. Here, we discuss how patient care was provided collaboratively by the local community teams integrated with remote specialist oncology services. A 77-year-old patient presented with symptoms of cauda equina secondary to a large metastatic sacral deposit. The deposit was biopsied, and histology revealed a diagnosis of differentiated follicular thyroid cancer that was treated with external beam radiotherapy and thyroidectomy, followed by radioiodine. However, the disease was found to be resistant to radioiodine therapy, and the patient subsequently developed back pain due to new bone metastases. After further palliative external beam radiotherapy, the patient was started on systemic treatment with lenvatinib. Treatment has continued for more than 2.5 years with a slow but steady improvement in symptoms and quality of life. Monitoring and assessment of lenvatinib therapy and management of associated toxicities was coordinated remotely from a specialist cancer center over 200 miles away, using the skills of the local medical and nursing teams. This case report demonstrates how a cooperative effort using local teams and video-conferencing links to a specialist cancer center can be applied to safely treat a patient with a medication that may result in significant potential toxicities that require attentive and dynamic management.

Can Haematology Blood Tests at Time of Diagnosis Predict Response to Neoadjuvant Treatment in Locally Advanced Rectal Cancer?

BACKGROUND: Outcomes in locally advanced rectal cancer are improved by neoadjuvant therapy followed by surgical resection. Some patients respond completely to preoperative treatment. Therefore, predicting the pathological response to preoperative therapy is of clinical importance. Accurate prediction would allow for tailored approaches to neoadjuvant therapy. METHODS: All patients undergoing resection of rectal adenocarcinoma after neoadjuvant therapy between 2006 and 2015 were included in this cohort study. Patients were identified from a prospectively collected database and data were supplemented retrospectively with full blood count at diagnosis. Specimens resected following neoadjuvant therapy were graded according to pathological response. Follow-up data was obtained from the national registry. The primary outcome was complete pathological response. RESULTS: Of 330 patients, 71 (21.5%) responded completely to preoperative therapy. Median age was 66 and 65% were male (n = 215). White cell count (WCC) was the most predictive marker, for predicting pCR; area under the curve (AUC) 0.666. This was higher than neutrophil/platelet ratio (AUC 0.652) or neutrophil/lymphocyte ratios (AUC = 0.437). Kaplan-Meier survival analysis showed those patients with WCC > 8 had poorer survival than those with WCC < 8 (p = 0.009). CONCLUSION: Routinely collected haematology samples at the point of diagnosis can assist in predicting for complete response to neoadjuvant therapy. Although novel biomarkers will have a greater predictive value, this clinically available value test could help to assist in risk stratification of patients using routinely collected laboratory tests.

Phase II Study of the Dual EGFR/HER3 Inhibitor Duligotuzumab (MEHD7945A) versus Cetuximab in Combination with FOLFIRI in Second-Line RAS Wild-Type Metastatic Colorectal Cancer.

Purpose: Duligotuzumab is a dual-action antibody directed against EGFR and HER3.Experimental Design: Metastatic colorectal cancer (mCRC) patients with KRAS ex2 wild-type received duligotuzumab or cetuximab and FOLFIRI until progression or intolerable toxicity. Mandatory tumor samples underwent mutation and biomarker analysis. Efficacy analysis was conducted in patients with RAS exon 2/3 wild-type tumors.Results: Of 134 randomly assigned patients, 98 had RAS ex2/3 wild-type. Duligotuzumab provided no progression-free survival (PFS) or overall survival (OS) benefit compared with cetuximab, although there was a trend for a lower objective response rate (ORR) in the duligotuzumab arm. No relationship was seen between PFS or ORR and ERBB3, NRG1, or AREG expression. There were fewer skin rash events for duligotuzumab but more diarrhea. Although the incidence of grade ≥3 AEs was similar, the frequency of serious AEs was higher for duligotuzumab.Conclusions: Duligotuzumab plus FOLFIRI did not appear to improve the outcomes in patients with RAS exon 2/3 wild-type mCRC compared with cetuximab + FOLFIRI. Clin Cancer Res; 24(10); 2276-84. ©2018 AACR.

Stochastic Pharmacokinetic-Pharmacodynamic Modeling for Assessing the Systemic Health Risk of Perfluorooctanoate (PFOA).

A phase 1 dose-escalation trial assessed the chemotherapeutic potential of ammonium perfluorooctanoate (APFO). Forty-nine primarily solid-tumor cancer patients who failed standard therapy received weekly APFO doses (50-1200 mg) for 6 weeks. Clinical chemistries and plasma PFOA (anionic APFO) were measured predose and weekly thereafter. Several clinical measures including total cholesterol, high-density lipoproteins (HDLs), thyroid stimulating hormone (TSH), and free thyroxine (fT4), relative to PFOA concentrations were examined by: Standard statistical analyses using generalized estimating equations (GEE) and a probabilistic analysis using probability distribution functions (pdf) at various PFOA concentrations; and a 2-compartment pharmacokinetic/pharmacodynamic (PK/PD) model to directly estimate mean changes. Based on the GEE, the average rates of change in total cholesterol and fT4 associated with increasing PFOA were approximately -1.2×10-3 mmol/l/µM and 2.8×10-3 pmol/l/µM, respectively. The PK/PD model predicted more closely the trends observed in the data as well as the pdfs of biomarkers. A decline in total cholesterol was observed, with a clear transition in shape and range of the pdfs, manifested by the maximum value of the Kullback-Leibler (KL) divergence, that occurred at plasma PFOA between 420 and 565 µM (175 000-230 000 ng/ml). High-density lipoprotein was unchanged. An increase in fT4 was observed at a higher PFOA transition point, albeit TSH was unchanged. Our findings are consistent with some animal models and may motivate re-examination of the epidemiologic studies to PFOA at levels several orders of magnitude lower than this study. These observational studies have reported contrary associations, but currently understood biology does not support the existence of such conflicting effects.

Inhibition of EGFR, HER2, and HER3 signalling in patients with colorectal cancer wild-type for BRAF, PIK3CA, KRAS, and NRAS (FOCUS4-D): a phase 2-3 randomised trial.

BACKGROUND: A substantial change in trial methodology for solid tumours has taken place, in response to increased understanding of cancer biology. FOCUS4 is a phase 2-3 trial programme testing targeted agents in patients with advanced colorectal cancer in molecularly stratified cohorts. Here, we aimed to test the hypothesis that combined inhibition of EGFR, HER2, and HER3 signalling with the tyrosine kinase inhibitor AZD8931 will control growth of all wild-type tumours. METHODS: In FOCUS4-D, we included patients from 18 hospitals in the UK with newly diagnosed advanced or metastatic colorectal cancer whose tumour was wild-type for BRAF, PIK3CA, KRAS, and NRAS. After 16 weeks of first-line therapy, patients with stable or responding tumours were randomised to oral AZD8931 (40 mg twice a day) or placebo. Randomisation was done by minimisation with a random element of 20%, minimisation by hospital site, site of primary tumour, WHO performance status, 16-week CT scan result, number of metastatic sites, and first-line chemotherapy regimen. The primary outcome was progression-free-survival. CT scans were assessed by local radiologists according to Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1. Preplanned interim analyses were assessed per protocol and were agreed using multiarm multistage (MAMS) trial design methodology triggered by occurrence of progression-free survival events in the placebo group. The final analysis was assessed by intention to treat. This trial is registered at controlled-trials.com, ISRCTN 90061546. FINDINGS: Between July 7, 2014, and March 7, 2016, 32 patients were randomised to study treatment, 16 to AZD8931 and 16 to placebo. At the first preplanned interim analysis (March, 2016), the independent data monitoring committee (IDMC) recommended closure of FOCUS4-D because of a lack of activity. At the final analysis (Aug 1, 2016), 31 patients had had a progression-free survival event (15 with AZD8931 and 16 with placebo). Median progression-free survival was 3·48 months (95% CI 1·51-5·09) in the placebo group and 2·96 months (1·94-5·62) in the AZD8931 group. No progression-free survival benefit of AZD8931 compared with placebo was noted (hazard ratio [HR] 1·10, 95% CI 0·47-3·57; p=0·95). The most common grade 3 adverse event in the AZD8931 group was skin rash (three [20%] of 15 patients with available data vs none of 16 patients in the placebo group), and in the placebo group it was diarrhoea (one [7%] vs one [6%]). No grade 4 adverse events were recorded and no treatment-related deaths were reported. INTERPRETATION: The MAMS trial design for FOCUS4 has shown efficiency and effectiveness in trial outcome delivery, informing the decision to proceed or stop clinical evaluation of a targeted treatment within a molecularly defined cohort of patients. The overarching FOCUS4 trial is now aiming to open a replacement arm in the cohort with all wild-type tumours. FUNDING: Medical Research Council (MRC) and National Institute for Health Research (NIHR) Efficacy and Mechanism Evaluation programme, Cancer Research UK, NIHR Clinical Trials Research Network, Health and Care Research Wales, and AstraZeneca.

Randomized study of etirinotecan pegol versus irinotecan as second-line treatment for metastatic colorectal cancer.

PURPOSE: Etirinotecan pegol (EP) is a long-acting topoisomerase-I inhibitor designed to provide sustained exposure to SN-38 (active metabolite of irinotecan). This phase II study compared EP versus irinotecan as second-line treatment for KRAS-mutant, irinotecan-naïve, metastatic colorectal cancer (mCRC). METHODS: Patients were randomized to EP 145 mg/m2 or irinotecan 350 mg/m2 Q21d until disease progression/unacceptable toxicity. The primary endpoint was progression-free survival (PFS) with response determined by central radiologic review (RECIST version 1.1). RESULTS: The study was terminated before completing accrual due to evolving standards of care. Eighty-three patients were randomized. Median PFS was longer with EP versus irinotecan (4.0 versus 2.8 months, respectively; HR 0.65; 95% CI 0.40-1.04; P = 0.07). Six-month PFS rates were 32.8 and 15.4%, respectively. Median OS was 9.6 and 8.4 months in EP and irinotecan arms, respectively (HR 0.91; 95% CI 0.56-1.49). ORRs were 10 and 5%, respectively (P = 0.676); median DOR was significantly longer in EP arm (7.9 versus 1.4 months; P = 0.018). The most common grade-3/4 adverse events for EP and irinotecan were diarrhea (21 vs 20%), neutropenia (10 vs 22%), abdominal pain (14 vs 5%), nausea (14 vs 2%), and vomiting (12 vs 7%), respectively. CONCLUSION: EP is active and safe for second-line treatment of KRAS-mutant, irinotecan-naïve mCRC.

Preoperative chemoradiation with capecitabine, irinotecan and cetuximab in rectal cancer: significance of pre-treatment and post-resection RAS mutations.

BACKGROUND: The influence of EGFR pathway mutations on cetuximab-containing rectal cancer preoperative chemoradiation (CRT) is uncertain. METHODS: In a prospective phase II trial (EXCITE), patients with magnetic resonance imaging (MRI)-defined non-metastatic rectal adenocarinoma threatening/involving the surgical resection plane received pelvic radiotherapy with concurrent capecitabine, irinotecan and cetuximab. Resection was recommended 8 weeks later. The primary endpoint was histopathologically clear (R0) resection margin. Pre-planned retrospective DNA pyrosequencing (PS) and next generation sequencing (NGS) of KRAS, NRAS, PIK3CA and BRAF was performed on the pre-treatment biopsy and resected specimen. RESULTS: Eighty-two patients were recruited and 76 underwent surgery, with R0 resection in 67 (82%, 90%CI: 73-88%) (four patients with clinical complete response declined surgery). Twenty-four patients (30%) had an excellent clinical or pathological response (ECPR). Using NGS 24 (46%) of 52 matched biopsies/resections were discrepant: ten patients (19%) gained 13 new resection mutations compared to biopsy (12 KRAS, one PIK3CA) and 18 (35%) lost 22 mutations (15 KRAS, 7 PIK3CA). Tumours only ever testing RAS wild-type had significantly greater ECPR than tumours with either biopsy or resection RAS mutations (14/29 [48%] vs 10/51 [20%], P=0.008), with a trend towards increased overall survival (HR 0.23, 95% CI 0.05-1.03, P=0.055). CONCLUSIONS: This regimen was feasible and the primary study endpoint was met. For the first time using pre-operative rectal CRT, emergence of clinically important new resection mutations is described, likely reflecting intratumoural heterogeneity manifesting either as treatment-driven selective clonal expansion or a geographical biopsy sampling miss.

Natural killer-like signature observed post therapy in locally advanced rectal cancer is a determinant of pathological response and improved survival.

Around 12-15% of patients with locally advanced rectal cancer undergo a pathologically complete response (tumor regression grade 4) to long-course preoperative chemoradiotherapy; the remainder exhibit a spectrum of tumor regression (tumor regression grade 1-3). Understanding therapy-related transcriptional alterations may enable better prediction of response as measured by progression-free and overall survival, in addition to aiding the development of improved strategies based on the underlying biology of the disease. To this end, we performed high-throughput gene expression profiling in 40 pairs of formalin-fixed paraffin-embedded rectal cancer biopsies and matched resections following long-course preoperative chemoradiotherapy (discovery cohort). Differential gene expression analysis was performed contrasting tumor regression grades in resections. Enumeration of the tumor microenvironment cell population was undertaken using in silico analysis of the transcriptional data, and real-time PCR validation of NCR1 undertaken. Immunohistochemistry and survival analysis was used to measure CD56+ cell populations in an independent cohort (n=150). Gene expression traits observed following long-course preoperative chemoradiotherapy in the discovery cohort suggested an increased abundance of natural killer cells in tumors that displayed a clinical response to CRT in a tumor regression grade-dependent manner. CD56+ natural killer-cell populations were measured by immunohistochemistry and found to be significantly higher in tumor regression grade 3 patients compared with tumor regression grade 1-2 in the validation cohort. Furthermore, it was observed that patients positive for CD56 cells after therapy had a better overall survival (HR=0.282, 95% CI=0.109-0.729, χ2=7.854, P=0.005). In conclusion, we have identified a novel post-therapeutic natural killer-like transcription signature in patients responding to long-course preoperative chemoradiotherapy. Furthermore, patients with a higher abundance of CD56-positive natural killer cells post long-course preoperative chemoradiotherapy had better overall survival. Therefore, harnessing a natural killer-like response after therapy may improve outcomes for locally advanced rectal cancer patients. Finally, we hypothesize that future assessment of this natural killer-like response in on-treatment biopsy material may inform clinical decision-making for treatment duration.