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Identification of circulating tumor DNA (ctDNA) following curative intent therapies is a surrogate for microscopic residual disease for patients with metastatic colorectal cancer (mCRC). Preclinically, in micrometastatic microsatellite stable (MSS) colorectal cancer, increased TGFβ signaling results in exclusion of antitumor cytotoxic T cells from the tumor microenvironment. Bintrafusp alfa (BA) is a bifunctional fusion protein composed of the extracellular domain of the TGFβRII receptor (“TGFβ trap”) and anti-PD-L1 antibody. Patients with liver-limited, MSS mCRC and with detected ctDNA after complete resection of all known tumors and standard-of-care therapy were treated with 1,200 mg of BA intravenously every 14 days for six doses. The primary endpoint was ctDNA clearance. Radiographic characteristics at recurrence were compared using independent t tests to historical data from a similar cohort of patients with liver-limited mCRC who underwent observation. Only 4 of 15 planned patients received BA before the study was stopped early for loss of equipoise. There was no grade ≥3 adverse event. None of the patients cleared ctDNA. All patients developed radiographic recurrence by the first planned restaging. Although not detectable at prior to treatment, TGFβ3 was found in circulation in all patients at cycle 2 day 1. Compared with a historical cohort, patients administered BA developed more metastases (15 vs. 2, P = 0.005) and greater tumor volumes (9 cm vs. 2 cm, P = 0.05). Treatment with BA in patients with ctDNA-detected, liver-limited mCRC did not clear ctDNA and was associated with large-volume recurrence, highlighting the potential context-specific complexity of dual TGFβ and PD-L1 inhibition. Significance: Use of ctDNA to identify patients with micrometastatic disease for therapeutic intervention is feasible. Treatment with BA in patients with liver-limited mCRC and with detectable ctDNA after resection generated rapid progression. Approaches targeting TGFβ signaling must consider its pathway complexity in future immunotherapy combination strategies.

Definitive radiation therapy with concurrent chemotherapy is curative for nonmetastatic squamous cell carcinoma of the anus (SCCA). However, the true effect of chemoradiation on long-term functional outcomes is poorly understood owing to limited follow-up and patient-reported outcomes (PROs).We conducted a cross-sectional survey of 248 patients with SCCA treated with definitive intensity modulated radiation and concurrent chemotherapy from 2010 to 2018 who were alive and without recurrence. PRO measures were collected, including Functional Assessment of Cancer Therapy-General (FACT-G7), Fecal Incontinence Quality of Life (FIQoL), Low Anterior Resection Syndrome (LARS), and International Consultation on Incontinence Questionnaires (ICIQ). Models were used to determine the association between demographic, tumor, treatment, and dosimetric data with PROs.One hundred twelve (45%) patients completed PROs. Median [interquartile range (IQR)] time from radiation completion to survey was 51 [37-85] months. The median scores [IQR] for FACT-G7, FIQoL, and LARS were 21 [15-24], 14 [11-16], and 32 [25-37], respectively. For men, median subscores [IQR] for ICIQ voiding and incontinence subscores were 5 [2-6] and 1 [1-3], respectively. For women, median subscores [IQR] for ICIQ voiding, incontinence, and filling were 1 [1-3], 5 [3-8], and 4 [2-5], respectively. Higher (better) FIQoL scores were associated with higher (better) FACT-G7 scores (β = 0.83; 95% confidence interval, 0.58-1.09; P.001), and higher (worse) LARS scores were associated with lower (worse) FACT-G7 scores (β = -0.22; 95% confidence interval, -0.31 to -0.13; P.001). A separate multivariable analysis revealed higher bowel bag D1% was associated with lower (worse) FIQoL (P = .001) and higher (worse) LARS (P = .003) scores. Higher bladder V40 Gy was associated with increased (worse) ICIQ voiding subscore (P = .001).Patients treated with modern chemoradiation for SCCA experience significant long-term bowel toxic effects with considerable effect on quality of life. Minimizing bowel hotspots and bladder V40 Gy may improve bowel and urinary function. Other interventions to reduce long-term toxic effects and improve quality of life are needed.

Background Immune checkpoint blockade (ICB) has improved outcomes for patients with microsatellite instability high (MSI-H)/deficient mismatch repair (dMMR) tumors. However, not all MSI-H/dMMR patients will exhibit the same ICB efficacy. Previous studies suggest that concomitant antibiotic use while receiving ICB may result in poorer outcomes. We aimed to evaluate this association in patients with MSI-H/dMMR metastatic colorectal cancer (mCRC). Materials and Methods A single-site, retrospective review of 57 patients with MSI-H/dMMR mCRC that received ICB was completed. Data collected included patient demographics, ICB information, and antibiotic use. Antibiotic exposure was considered from 90 days prior to ICB through 6 weeks after initiation. Primary endpoint was overall response rate (ORR). Results The majority of patients received pembrolizumab (27 [47%]) or nivolumab (17 [30%]) monotherapy as their ICB agent. Of the 57 patients, 19 (33.3%) had antibiotic exposure from 90 days prior to ICB initiation through 6 weeks after initiation with most (13 [68%]) having antibiotic use in the 30 days preceding ICB initiation. Similar ORRs were seen in both groups (P-value > .99). No difference was observed in OS (P-value .29) or PFS (P-value .36) between groups. Conclusion Our data show no association of lower response rates or survival in those MSI-H/dMMR patients with mCRC who receive antibiotics around the initiation of ICB. This information needs to be confirmed in a larger prospective cohort.

KRAS and NRAS mutations occur in 45% of colorectal cancers, with combined MAPK pathway and CDK4/6 inhibition identified as a potential therapeutic strategy. In the current study, this combinatorial treatment approach was evaluated in a co-clinical trial in patient-derived xenografts (PDX), and safety was established in a clinical trial of binimetinib and palbociclib in patients with metastatic colorectal cancer with RAS mutations. Across 18 PDX models undergoing dual inhibition of MEK and CDK4/6, 60% of tumors regressed, meeting the co-clinical trial primary endpoint. Prolonged duration of response occurred predominantly in TP53 wild-type models. Clinical evaluation of binimetinib and palbociclib in a safety lead-in confirmed safety and provided preliminary evidence of activity. Prolonged treatment in PDX models resulted in feedback activation of receptor tyrosine kinases and acquired resistance, which was reversed with a SHP2 inhibitor. These results highlight the clinical potential of this combination in colorectal cancer, along with the utility of PDX-based co-clinical trial platforms for drug development. Significance: This co-clinical trial of combined MEK-CDK4/6 inhibition in RAS mutant colorectal cancer demonstrates therapeutic efficacy in patient-derived xenografts and safety in patients, identifies biomarkers of response, and uncovers targetable mechanisms of resistance.

Patients with localized squamous cell carcinoma of the anus (SCCA) who experience treatment toxicity or recurrences have few therapeutic options. Investigation into the microbiome's influence on treatment toxicity and its potential use as a predictive biomarker could improve these patients' outcomes. Our study presents the first longitudinal characterization of the SCCA tumor microbiome and its associations with treatment-related toxicities.This prospective cohort study included patients with nonmetastatic SCCA receiving standard-of-care chemoradiation therapy. Anorectal swabs of the tumor site were collected before, during, and after treatment. Patient-reported quality-of-life metrics were collected at similar time points. 16S rRNA gene sequencing was used to perform diversity and taxonomic characterization of the SCCA microbiome. Wilcoxon signed-rank tests were used to compare microbial diversity and abundance over time. Wilcoxon rank-sum tests were used to compare microbial profiles of high and low toxicity groups.Twenty-two patients with SCCA were included in this study with a median age of 58.5 years (range, 39-77 years), and 18 (82%) were women. Alpha diversity remained relatively stable throughout chemoradiation therapy except for decreases in the Observed Features (P = .03) index at week 5 relative to baseline. Tumor microbial compositions changed significantly by the end of treatment (P = .03). Differential enrichment of bacteria at specific time points occurred during treatment, including the enrichment of Clostridia at follow-up (vs week 5, q = 0.019) and Corynebacterium at week 5 (vs baseline, q = 0.015; vs follow-up, q = 0.022). Patients experiencing high toxicity at week 5 had higher relative counts of Clostridia, Actinobacteria, and Clostridiales at baseline (P = .03 for all).The tumor microbiome changes during and after chemoradiation therapy, and patient-reported toxicity levels are associated with patients' microbial profiles. Further studies into these microbial characterizations and toxicity associations will elucidate the tumor microbiome's role in predicting treatment-related outcomes for patients with SCCA.

PURPOSE Burnout is a psychological occupational syndrome defined by the Maslach Burnout Inventory (MBI) as emotional exhaustion, depersonalization, and a low sense of personal accomplishment. We sought to characterize the prevalence of burnout among early-career medical oncologists at The University of Texas MD Anderson Cancer Center (MDACC). METHODS For this institutional review board–approved study, an electronic survey was developed for Assistant Professors in the MDACC Division of Cancer Medicine. All participants were involved directly in patient care. Our survey included questions assessing self-reported burnout, nine questions validated in the abbreviated MBI, and 31 questions to assess potential contributors to burnout. Each question was scaled 1-5, with higher scores associated with higher burnout. Descriptive statistics were used to estimate the prevalence of burnout, and logistic regression analyses were performed to identify contributing factors. RESULTS Among 86 Assistant Professors, 56 (65%) responded to the survey. The mean duration on faculty was 3.1 years. The mean clinical effort was 67% (range, 19-95). Fifty-four percent of respondents self-reported symptoms of burnout including 21% indicating severe burnout. Using the MBI, sentiments of being emotionally drained (54%), fatigued facing another day on the job (45%), and becoming more callous (30%) were especially notable. Twenty-five percent of respondents exhibited severe emotional exhaustion, which was more prevalent ( P < .0001) than depersonalization (6%) or lack of personal accomplishment (17%). CONCLUSION Burnout exists with high prevalence among early-career medical oncologists, with emotional exhaustion being the most common manifestation of burnout. Interventions focusing on reducing emotional exhaustion are needed to reduce burnout among early-career medical oncologists.

Background Human papillomavirus (HPV) types 16/18 drive oncogenesis for most patients with cervical, anal, and penile cancers. MEDI0457, a therapeutic DNA vaccine containing plasmids for E6 and E7 HPV-16/18 viral oncogenes and IL-12 adjuvant, is safe and provokes an immune response against E6/E7. We tested MEDI0457 with the anti-PD-L1 antibody durvalumab for patients with HPV-associated cancers. Methods Patients with recurrent/metastatic, treatment-refractory HPV-16/18 cervical cancer, or rare HPV-associated (anal and penile) cancers were eligible. Prior immune checkpoint inhibition was not permitted. Patients received MEDI0457 7 mg intramuscularly (weeks 1, 3, 7, 12, and every 8 weeks thereafter) and durvalumab 1500 mg intravenously every 4 weeks. The primary endpoint was overall response (RECIST 1.1). In this Simon two-stage phase 2 trial (Ho: p Results Twenty-one patients (12 cervical, 7 anal, and 2 penile) were evaluable for toxicity and 19 for response Overall response rate was 21% (95% CI, 6%-46%) among evaluable patients. Disease control rate was 37% (95% CI, 16%-62%). Median duration of response among responders was 21.8 months (95% CI, 9.7%-not estimable). Median progression-free survival was 4.6 months (95% CI, 2.8%-7.2%). Median overall survival was 17.7 months (95% CI, 7.6%-not estimable). Grades 3-4 treatment-related adverse events occurred in 6 (23%) participants. Conclusions The combination of MEDI0457 and durvalumab demonstrated acceptable safety and tolerability in patients with advanced HPV-16/18 cancers. The low ORR among patients with cervical cancer led to study discontinuation despite a clinically meaningful disease control rate.

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Identification of circulating tumor DNA (ctDNA) following curative intent therapies is a surrogate for microscopic residual disease for patients with metastatic colorectal cancer (mCRC). Preclinically, in micrometastatic microsatellite stable (MSS) colorectal cancer, increased TGFβ signaling results in exclusion of antitumor cytotoxic T cells from the tumor microenvironment. Bintrafusp alfa (BA) is a bifunctional fusion protein composed of the extracellular domain of the TGFβRII receptor (“TGFβ trap”) and anti-PD-L1 antibody. Patients with liver-limited, MSS mCRC and with detected ctDNA after complete resection of all known tumors and standard-of-care therapy were treated with 1,200 mg of BA intravenously every 14 days for six doses. The primary endpoint was ctDNA clearance. Radiographic characteristics at recurrence were compared using independent t tests to historical data from a similar cohort of patients with liver-limited mCRC who underwent observation. Only 4 of 15 planned patients received BA before the study was stopped early for loss of equipoise. There was no grade ≥3 adverse event. None of the patients cleared ctDNA. All patients developed radiographic recurrence by the first planned restaging. Although not detectable at prior to treatment, TGFβ3 was found in circulation in all patients at cycle 2 day 1. Compared with a historical cohort, patients administered BA developed more metastases (15 vs. 2, P = 0.005) and greater tumor volumes (9 cm vs. 2 cm, P = 0.05). Treatment with BA in patients with ctDNA-detected, liver-limited mCRC did not clear ctDNA and was associated with large-volume recurrence, highlighting the potential context-specific complexity of dual TGFβ and PD-L1 inhibition.Significance:Use of ctDNA to identify patients with micrometastatic disease for therapeutic intervention is feasible. Treatment with BA in patients with liver-limited mCRC and with detectable ctDNA after resection generated rapid progression. Approaches targeting TGFβ signaling must consider its pathway complexity in future immunotherapy combination strategies.

68-gene panel for which mutation, amplification, deletion, and fusion profiling was available.

Trends in various mutation allele frequencies tracked serially over treatment course for two patients on study.

Demographic information for patients on study.

Trends in cfDNA fraction (black) and radiographic changes (red) for ten other patients on study.

Analysis of BRAFV600E allele fraction by cfDNA was validated using two separate methodologies.

Heatmap showing fRMA level gene data from Affymetrix subsets in training and validation datasets.

Supplementary methods and results

Validation of CMS assay at the research molecular diagnostic laboratory. Each sample classified in to CMS subtype 1-4 or mixed (M) subtype.

Supplementary Figure from Targeting RAS Mutant Colorectal Cancer with Dual Inhibition of MEK and CDK4/6

3A. Classification accuracy of CMS1 samples on training data set V1 using 4-fold cross validation as function of number of genes.3B.able-3B: Classification accuracy of CMS1 samples on validation data set (V2) as function of number of genes.3C. Classification accuracy CMS1 samples with out of sample (V2o) prediction set as function of number of genes.3D. Classification accuracy CMS1 samples with TCGA dataset (RNA-seq subset) as function of number of genes. 3E. Classification accuracy CMS1 samples with Affymetrix set (V2a) as function of number of genes.

Kaplan-Meier estimation of (A) overall survival of BRAFV600E mCRC NGS cohorts and (B) progression free survival of BRAFV600E mCRC NGS cohorts from BC Cancer and MD Anderson shows no difference in overall or progression free survival.

Comparison of overall survival based on primary tumor side using a multivariate proportional hazards model controlling for co-variates that differed based on tumor location.

Sensitivity analysis comparing mutation prevalence estimates by site of biopsy of tissue used for next generation sequencing panel in metastatic colorectal cancer.

Classification accuracy on validation data set, the entire set (V2), out-of-sample prediction (V2o), Affymetrix subset (V2a), and TCGA RNAseq subset (TCGA) for various methods as function of number of genes.

Supplemental legend

Purpose:Consensus molecular subtyping (CMS) of colorectal cancer has potential to reshape the colorectal cancer landscape. We developed and validated an assay that is applicable on formalin-fixed, paraffin-embedded (FFPE) samples of colorectal cancer and implemented the assay in a Clinical Laboratory Improvement Amendments (CLIA)-certified laboratory.Experimental Design:We performed an in silico experiment to build an optimal CMS classifier using a training set of 1,329 samples from 12 studies and validation set of 1,329 samples from 14 studies. We constructed an assay on the basis of NanoString CodeSets for the top 472 genes, and performed analyses on paired flash-frozen (FF)/FFPE samples from 175 colorectal cancers to adapt the classifier to FFPE samples using a subset of genes found to be concordant between FF and FFPE, tested the classifier's reproducibility and repeatability, and validated in a CLIA-certified laboratory. We assessed prognostic significance of CMS in 345 patients pooled across three clinical trials.Results:The best classifier was weighted support vector machine with high accuracy across platforms and gene lists (>0.95), and the 472-gene model outperforming existing classifiers. We constructed subsets of 99 and 200 genes with high FF/FFPE concordance, and adapted FFPE-based classifier that had strong classification accuracy (>80%) relative to “gold standard” CMS. The classifier was reproducible to sample type and RNA quality, and demonstrated poor prognosis for CMS1–3 and good prognosis for CMS2 in metastatic colorectal cancer (P < 0.001).Conclusions:We developed and validated a colorectal cancer CMS assay that is ready for use in clinical trials, to assess prognosis in standard-of-care settings and explore as predictor of therapy response.

Nanostring CMS Classifier Performance: Performance of Nanostring 100 gene CMS classifier applied to FFPE samples (6A and 6C) and FF samples (6B and 63D). The top two figures plot 4-class accuracy vs. classification confidence, with the dots marking individual samples either correctly (1.0) or incorrectly (0.0), with color indicat-ing correct CMS. The line contains a generalized additive model (GAM) fit to these data with 95% pointwise confidence bands, and demonstrates that samples classified with greater confidence were more likely to be cor-rectly classified. Figure 6C and 6D plot 4-class accuracy vs. RNA quality, defined as 0nt (FFPE) or RIN (FF). Note that there is little if any association of CMS accuracy with RNA quality, suggesting that the perfor-mance of classifier is robust to RNA quality in this study.

Prevalence of BRAFV600E mutated colorectal cancer by IHC testing within VCH population-based cohort.

Classification accuracy of different modelling strategies on training data set (V1) using 4-fold cross validation.

Comparison of Classifiers. Comparison of random forest (RF) and single sample predictors (SSP) in Guinney et al. (2015) paper with our wSVM classifier with 472 genes, either forcing a single CMS call for each sample (all calls) or only when classified with high confidence

KRAS and NRAS mutations occur in 45% of colorectal cancers, with combined MAPK pathway and CDK4/6 inhibition identified as a potential therapeutic strategy. In the current study, this combinatorial treatment approach was evaluated in a co-clinical trial in patient-derived xenografts (PDX), and safety was established in a clinical trial of binimetinib and palbociclib in patients with metastatic colorectal cancer with RAS mutations. Across 18 PDX models undergoing dual inhibition of MEK and CDK4/6, 60% of tumors regressed, meeting the co-clinical trial primary endpoint. Prolonged duration of response occurred predominantly in TP53 wild-type models. Clinical evaluation of binimetinib and palbociclib in a safety lead-in confirmed safety and provided preliminary evidence of activity. Prolonged treatment in PDX models resulted in feedback activation of receptor tyrosine kinases and acquired resistance, which was reversed with a SHP2 inhibitor. These results highlight the clinical potential of this combination in colorectal cancer, along with the utility of PDX-based co-clinical trial platforms for drug development.Significance:This co-clinical trial of combined MEK-CDK4/6 inhibition in RAS mutant colorectal cancer demonstrates therapeutic efficacy in patient-derived xenografts and safety in patients, identifies biomarkers of response, and uncovers targetable mechanisms of resistance.

Supplementary Table from Targeting RAS Mutant Colorectal Cancer with Dual Inhibition of MEK and CDK4/6

5A. Classification accuracy of CMS 3 samples on training data set V1 using 4-fold cross validation as function of number of genes. 5B.Classification accuracy of CMS 3 samples on validation data set (V2) as function of number of genes. 5C. Classification accuracy CMS3 samples with out of sample prediction set (V2o) as function of number of genes. 5D. Classification accuracy CMS 3 samples with TCGA dataset (RAN-seq subset) as function of number of genes. 5E. Classification accuracy CMS3 samples with Affymetrix dataset (V2a) as function of number of genes.

6A. Classification accuracy of CMS 4 samples on training data set V1 using 4-fold cross validation as function of number of genes. 6B. Classification accuracy of CMS 4 samples on validation data set (V2) as function of number of genes. 6C. Classification accuracy CMS 4 samples with out of sample prediction set (V2o) as function of number of genes. 6D. Classification accuracy CMS 3 samples with TCGA dataset (RAN-seq subset) as function of number of genes. 6E. Classification accuracy of CMS 3 samples with Affymetrix data set (V2a) as function of number of genes.

Sample-wise and Gene-wise correlation of FF/FFPE paired Samples: Scatterplot of gene-specific Spearman correlation of FF/FFPE computed separately for CRCSC samples and non-CRCSC samples , with red and blue marking the overall top 100 and top 200 genes, respectively, in terms of FF/FFPE correlation computed across all samples. Note the high level of agreement across batches that genes with high FF/FFPE correlations for one batch tended to also have high FF/FFPE correlation in the other batch, suggesting high FF/FFPE correla-tion is a characteristic of the gene/probe set.

Summary of the relative prognostic and mutational impact of tumor location in metastatic colorectal cancer. Sub-caption: Relative prevalence of mutations at each site was compared to the median prevalence across all sites and used to calculate relative font size for each gene name. Hazard ratios displayed in the figure utilize rectal location as the reference category.

Sensitivity analysis demonstrating optimal left vs right cut-point to maximize prognostic differences based on side in metastatic colorectal cancer. Sub-caption: Numbers in figure represent the hazard ratio followed by the 95% confidence interval within square brackets. The hazard ratio estimate occurs at the location used to divide left from right in each sensitivity analysis. For example, if the division between right and left occurs between the hepatic flexure and transverse colon, the hazard ratio estimate will be placed on the graph half way between the hepatic flexure and transverse colon (ie. 1.66).

Supplementary Data from Targeting RAS Mutant Colorectal Cancer with Dual Inhibition of MEK and CDK4/6

Purpose: Colorectal cancers are classified as right/left-sided based on whether they occur before/after the splenic flexure, with established differences in molecular subtypes and outcomes. However, it is unclear if this division is optimal and whether precise tumor location provides further information.Experimental Design: In 1,876 patients with colorectal cancer, we compared mutation prevalence and overall survival (OS) according to side and location. Consensus molecular subtype (CMS) was compared in a separate cohort of 608 patients.Results: Mutation prevalence differed by side and location for TP53, KRAS, BRAFV600, PIK3CA, SMAD4, CTNNB1, GNAS, and PTEN. Within left- and right-sided tumors, there remained substantial variations in mutation rates. For example, within right-sided tumors, RAS mutations decreased from 70% for cecal, to 43% for hepatic flexure location (P = 0.0001), while BRAFV600 mutations increased from 10% to 22% between the same locations (P < 0.0001). Within left-sided tumors, the sigmoid and rectal region had more TP53 mutations (P = 0.027), less PIK3CA (P = 0.0009), BRAF (P = 0.0033), or CTNNB1 mutations (P < 0.0001), and less MSI (P < 0.0001) than other left-sided locations. Despite this, a left/right division preceding the transverse colon maximized prognostic differences by side and transverse colon tumors had K-modes mutation clustering that appeared more left than right sided. CMS profiles showed a decline in CMS1 and CMS3 and rise in CMS2 prevalence moving distally.Conclusions: Current right/left classifications may not fully recapitulate regional variations in tumor biology. Specifically, the sigmoid-rectal region appears unique and the transverse colon is distinct from other right-sided locations. Clin Cancer Res; 24(5); 1062–72. ©2017 AACR.See related commentary by Dienstmann, p. 989

4A. Classification accuracy of CMS2 samples on training data set V1 using 4-fold cross validation as function of number of genes.4B. Classification accuracy of CMS2 samples on validation data set (V2) as function of number of genes.4C. Classification accuracy CMS2 samples with out of sample(V2o) prediction set as function of number of genes. 4D. Classification accuracy CMS2 samples with TCGA dataset (RNA-seq subset) as function of number of genes.4E. Classification accuracy CMS2 samples with Affymentrix dataset (V2a) as function of number of genes.

Algorithm showing strategy to de-velop the Nanostring based FFPE CMS classifier using Affymetrix gene expression data. FF: flash frozen, FFPE: Formalin fixed par-affin embedded, NFFPE: Nanos-tring FFPE, AFF: Flash frozen Affymetrix, GES: Gene expres-sion score, CRCSC: Colorectal cancer subtyping consortium

Classification Confidence of Affymetrix Validation Samples vs. Classification Accuracy of 472-gene wSVM clas-sifier: Distribution of classification confidence (�i) across 713 validation samples (top), and classification accura-cy (1=correct, 0=incorrect) as a function of classification confidence (�i), with fitted loess curve and 95% confidence interval.