Single-Cell Sequencing Reveals Trajectory of Tumor-Infiltrating Lymphocyte States in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) has few effective treatments. Immunotherapy, an attractive alternative strategy, remains challenging with the lack of knowledge on the tumor-infiltrating lymphocyte (TIL) landscape in PDAC. To generate a reference of T-cell subpopulations, we profiled 80,000 T cells from 57 PDAC samples, 22 uninvolved/normal samples, and cultured TIL using single-cell transcriptomic and T-cell receptor analysis. These data revealed 20 cell states and heterogeneous distributions of TIL populations. The CD8+ TIL contained a putative transitional GZMK+ population based on T-cell receptor clonotype sharing, and cell-state trajectory analysis showed similarity to a GZMB+PRF1+ cytotoxic and a CXCL13+ dysfunctional population. Statistical analysis suggested that certain TIL states, such as dysfunctional and inhibitory populations, often occurred together. Finally, analysis of cultured TIL revealed that high-frequency clones from effector populations were preferentially expanded. These data provide a framework for understanding the PDAC TIL landscape for future TIL use in immunotherapy for PDAC. SIGNIFICANCE: To improve the efficacy of immunotherapy in PDAC, there is a great need to understand the PDAC TIL landscape. This study represents a reference of PDAC TIL subpopulations and their relationships and provides a foundation upon which to base future immunotherapeutic efforts. This article is highlighted in the In This Issue feature, p. 2221.

Antibiotic use influences outcomes in advanced pancreatic adenocarcinoma patients.

Recent studies defined a potentially important role of the microbiome in modulating pancreatic ductal adenocarcinoma (PDAC) and responses to therapies. We hypothesized that antibiotic usage may predict outcomes in patients with PDAC. We retrospectively analyzed clinical data of patients with resectable or metastatic PDAC seen at MD Anderson Cancer from 2003 to 2017. Demographic, chemotherapy regimen and antibiotic use, duration, type, and reason for indication were recorded. A total of 580 patients with PDAC were studied, 342 resected and 238 metastatic patients, selected retrospectively from our database. Antibiotic use, for longer than 48 hrs, was detected in 209 resected patients (61%) and 195 metastatic ones (62%). On resectable patients, we did not find differences in overall survival (OS) or progression-free survival (PFS), based on antibiotic intake. However, in the metastatic cohort, antibiotic consumption was associated with a significantly longer OS (13.3 months vs. 9.0 months, HR 0.48, 95% CI 0.34-0.7, p = 0.0001) and PFS (4.4 months vs. 2 months, HR 0.48, 95% CI 0.34-0.68, p = <0.0001). In multivariate analysis, the impact of ATB remained significant for PFS (HR 0.59, p = 0.005) and borderline statistically significant for OS (HR 0.69, p = 0.06). When we analyzed by chemotherapy regimen, we found that patients who received gemcitabine-based chemotherapy as first-line therapy (n = 118) had significantly prolonged OS (HR 0.4, p 0.0013) and PFS (HR 0.55, p 0.02) if they received antibiotics, while those receiving 5FU-based chemotherapy (n = 98) had only prolonged PFS (HR 0.54, p = 0.03). Antibiotics-associated modulation of the microbiome is associated with better outcomes in patients with metastatic PDAC.

Trial Sponsorship and Time to Reporting for Phase 3 Randomized Cancer Clinical Trials.

The pace of clinical trial data generation and publication is an area of interest within clinical oncology; however, little is known about the dynamics and covariates of time to reporting (TTR) of trial results. To assess these, ClinicalTrials.gov was queried for phase three clinical trials for patients with metastatic solid tumors, and the factors associated with TTR from enrollment completion to publication were analyzed. Based on the 319 included trials, cooperative-group-sponsored trials were reported at a slower rate than non-cooperative-group trials (median 37.5 vs. 31.0 months; p < 0.001), while industry-funded studies were reported at a faster rate than non-industry-supported trials (31.0 vs. 40.0 months; p = 0.005). Furthermore, successful trials (those meeting their primary endpoint) were reported at a faster rate than unsuccessful studies (27.5 vs. 36.0 months; p < 0.001). Multivariable analysis confirmed that industry funding was independently associated with a shorter TTR (p = 0.006), while cooperative group sponsorship was not associated with a statistically significant difference in TTR (p = 0.18). These data underscore an opportunity to improve cooperative group trial efficiency by reducing TTR.

Modified gemcitabine plus nab-paclitaxel regimen in advanced pancreatic ductal adenocarcinoma.

BACKGROUND: Gemcitabine (GEM) plus nab-paclitaxel (NabP) (GEM 1000 mg/m2 IV over 30 minutes + NabP 125 mg/m2 IV given days 1, 8, and 15 every 28 days) is one of the two standard of care combination therapies for metastatic pancreatic ductal adenocarcinoma (PDAC). Our cancer center has utilized GEM-NabP given every two-weeks due to tolerability and patient convenience. Here, we review the safety and efficacy of this modified regimen. METHODS: Metastatic PDAC patients (pts) who initiated front-line or second-line GEM-NabP during 2013-2017 were retrospectively reviewed. Primary objective was overall survival. Secondary objectives were disease control rate, progression-free survival, and the incidence of dose delays and/or adjustments. RESULTS: From a total of 235 patients, 140 pts received GEM-NabP front-line while 95 pts received GEM-NabP second-line. Median dosing was 600 mg/m2 at fixed-dose rate for GEM and 125 mg/m2 for NabP given predominantly (~90%) every two-weeks. Eastern Cooperative Group performance status of 0 and 1 pts had front-line OS of 12.7 and 9.6 months and when given second-line had OS of 8 months and 7.3 months, respectively. ECOG 0 and 1 pts had front-line progression-free survival (PFS) of 5.3 months and 2.8 months and second-line PFS was 3.5 months and 2.4 months, respectively. Treatment was well tolerated with limited dose modifications. CONCLUSION: Our analysis revealed safety with every two-week low dose GEM-NabP while maintaining efficacy. Patient schedule convenience should factor into metastatic incurable malignancies. We suggest the use of every two-week GEM-NabP particularly in patients desiring a modified schedule.

A Randomized, Placebo-Controlled, Double-Blind Study of Minocycline for Reducing the Symptom Burden Experienced by Patients With Advanced Pancreatic Cancer.

CONTEXT: Although it is well known that patients with advanced pancreatic cancer (PC) experience significant symptom burden, few strategies for effective symptom intervention are available for them. OBJECTIVES: To investigate the efficacy of minocycline, an anti-inflammatory agent, for symptom reduction in patients with advanced PC. METHODS: We conducted Phase II, randomized, and placebo-controlled trial to obtain preliminary estimates of the effects on symptom reduction with 100 mg of minocycline or placebo given twice a day. Eligible patients had diagnosed advanced PC and were scheduled for standard chemotherapy. Patient-reported symptoms were measured weekly during the eight-week trial using the MD Anderson Symptom Inventory (MDASI) module in patients with gastrointestinal cancer. The primary outcome measure was the area under the curve values of the five most severe symptoms in the two arms. RESULTS: Of the 44 patients recruited, 31 (71%) were evaluable for the primary efficacy analysis, with 18 received minocycline and 13 placebo. Fatigue, pain, disturbed sleep, lack of appetite, and drowsiness were the most severe symptoms reported by both groups. No significant differences in area under the curve values over time between the study arms were found for the composite MDASI score or single-item scores of the five most severe MDASI items. No treatment-related deaths were reported, and no Grade 3-4 toxicities were observed. CONCLUSION: Minocycline is safe for use in patients receiving treatment for PC. There is no observed symptom reduction with minocycline on the major symptom burden associated with advanced PC compared with placebo. Attrition because of rapid disease progression impacted the study significantly.

Modified FOLFIRINOX in pancreatic cancer patients Age 75 or older.

BACKGROUND: Although FOLFIRINOX (5-Fluorouracil + leucovorin + irinotecan + oxaliplatin) is now the standard of care for patients (pts) with metastatic pancreatic cancer (PC) based on the 2011 study by Conroy et al. which demonstrated improved median overall survival (mOS), pts > 75 yrs old were excluded from this study. The purpose of this study was to assess the safety and efficacy of modified FOLFIRINOX (mFOLFIRINOX) in this population. METHODS: We retrospectively analyzed unresectable PC pts, age ≥ 75, treated with mFOLFIRINOX at MD Anderson from 2011 to 2017. Primary outcome was rate of grade 3 or 4 hematologic toxicity (HT). RESULTS: 24 pts were included. Grade 3 or 4 HT occurred in 11 pts 6 pts required hospitalization for any toxicity, and 10 stopped mFOLFIRINOX due to toxicity. The most frequently used starting doses of infusional 5-FU, irinotecan and oxaliplatin were 2400, 150 and 75 mg/m2, respectively. Median PFS was 3.7 months (95% CI: 3.0-5.7) with a median OS of 11.6 months (95% CI: 6.14-15.7). For first line pts, median PFS and OS were 5.1 (95% CI: 2.0-12.8) and 12.2 months (95% CI: 4.8-30.8), respectively. CONCLUSIONS: In this single-center retrospective analysis of unresectable PC pts age 75 or older given mFOLFIRINOX, toxicities and survival outcomes were similar to those reported in the initial study. These data indicate that the use of modified dosing FOLFIRINOX in advanced PC pts older than 75 appears to maintain similar toxicity and efficacy when compared to younger pts.

Cell-free Circulating Tumor DNA Variant Allele Frequency Associates with Survival in Metastatic Cancer.

PURPOSE: Physicians are expected to assess prognosis both for patient counseling and for determining suitability for clinical trials. Increasingly, cell-free circulating tumor DNA (cfDNA) sequencing is being performed for clinical decision making. We sought to determine whether variant allele frequency (VAF) in cfDNA is associated with prognosis. EXPERIMENTAL DESIGN: We performed a retrospective analysis of 298 patients with metastatic disease who underwent clinical comprehensive cfDNA analysis and assessed association between VAF and overall survival. RESULTS: cfDNA mutations were detected in 240 patients (80.5%). Median overall survival (OS) was 11.5 months. cfDNA mutation detection and number of nonsynonymous mutations (NSM) significantly differed between tumor types, being lowest in appendiceal cancer and highest in colon cancer. Having more than one NSM detected was associated with significantly worse OS (HR = 2.3; P < 0.0001). VAF was classified by quartiles, Q1 lowest, Q4 highest VAF. Higher VAF levels were associated with a significantly worse overall survival (VAF Q3 HR 2.3, P = 0.0069; VAF Q4 HR = 3.8, P < 0.0001) on univariate analysis. On multivariate analysis, VAF Q4, male sex, albumin level <3.5 g/dL, number of nonvisceral metastatic sites >0 and number of prior therapies >4 were independent predictors of worse OS. CONCLUSIONS: Higher levels of cfDNA VAF and a higher number of NSMs were associated with worse OS in patients with metastatic disease. Further study is needed to determine optimal VAF thresholds for clinical decision making and the utility of cfDNA VAF as a prognostic marker in different tumor types.

Germline DNA Sequencing Reveals Novel Mutations Predictive of Overall Survival in a Cohort of Patients with Pancreatic Cancer.

PURPOSE: Family history of BRCA-related tumors may correlate with response to chemotherapy and overall survival (OS) in pancreatic cancer. The frequency of germline mutations has been reported in patients predominantly under the age of 60 or with strong family history. We examine the incidence of deleterious germline mutations and compare the chemotherapy responses and OS in an unselected group of patients with metastatic pancreatic cancer. EXPERIMENTAL DESIGN: Patients with metastatic pancreatic cancer, who were seen at a single cancer center between 2010 and 2016, were included. Germline DNA was sequenced using a 263-gene panel to identify novel mutations (N = 133 MD Anderson cohort, N = 127 TCGA cohort). Chemotherapy response and OS were determined by review of medical records. RESULTS: Deleterious germline mutations were identified in 26 of 133 patients (19.5%). Patients with DNA damage repair (DDR) gene mutations (ATM, BRCA1/2, CDKN2A, CHEK2, ERCC4, PALB2, n = 15) had an improved OS as compared with patients without (16.8 vs. 9.1 months, P = 0.03). Conversely, patients with other deleterious mutations had a trend toward worse OS. However, survival in the latter group was longer (P = NS) in those mutants initially treated with gemcitabine/nab-paclitaxel. A family history of multiple breast, ovarian, and pancreatic cancers was associated with DDR gene mutations and better survival. CONCLUSIONS: We have identified novel germline mutations that are prognostic for survival in patients with pancreatic cancer. We observe improved survival in patients with DDR gene mutations and worsened survival in patients with deleterious mutations in non-DDR genes.

An open-label, single-arm pilot study of EUS-guided brachytherapy with phosphorus-32 microparticles in combination with gemcitabine +/- nab-paclitaxel in unresectable locally advanced pancreatic cancer (OncoPaC-1): Technical details and study protocol.

Current treatment options for patients with unresectable locally advanced pancreatic cancer (LAPC) include chemotherapy alone or followed by chemoradiation or stereotactic body radiotherapy. However, the prognosis for these patients remains poor, with a median overall survival <12 months. Therefore, novel treatment options are needed. Currently, there is no brachytherapy device approved for pancreatic cancer treatment. Hereby, we present the protocol of a prospective, multicenter, interventional, open-label, single-arm pilot study (OncoPac-1, Clinicaltrial.gov-NCT03076216) aiming to determine the safety and efficacy of Phosphorus-32 when implanted directly into pancreatic tumors using EUS guidance, for patients with unresectable LAPC undergoing chemotherapy (gemcitabine ± nab-paclitaxel).

Signet ring cell colorectal cancer: genomic insights into a rare subpopulation of colorectal adenocarcinoma.

BACKGROUND: Signet ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer (CRC). The aim of this study was to characterise the genomic alterations and outcomes of SRCC. METHODS: Medical records of metastatic CRC (mCRC) patients whose tumours were evaluated by NGS analysis were reviewed. SC-mCRC were classified into two groups: SRCC (>50% signet ring cells) and adenocarcinoma (AC) with SC component (≤50% signet ring cells). RESULTS: Six hundred and sixty-five mCRC patients were included. Of the 93 mCRC cases with SC features, 63 had slides for review. Of those 63 cases, 35 were confirmed SRCC, and 28 were AC with SC component. Compared with AC group, KRAS and PIK3CA mutations (mts) were found in only 11% (OR: 0.13) and 3% (OR: 0.15) of SRCC cases, respectively. In contrast to the 44% rate of APC mts in AC group, only 3% of SRCC patients had APC mts (OR = 0.04). CONCLUSIONS: SRCC has distinct molecular features, including low rates of KRAS, PIK3CA and APC mts. Further study to identify activation pathways and potential therapeutic targets are needed.

Benefit of Gemcitabine/Nab-Paclitaxel Rescue of Patients With Borderline Resectable or Locally Advanced Pancreatic Adenocarcinoma After Early Failure of FOLFIRINOX.

OBJECTIVES: Neoadjuvant therapy (NT) is used for advanced pancreatic ductal adenocarcinoma (PDAC). No clear guidelines exist for switching therapies when patients do not respond to initial NT. We sought to characterize patients who underwent early switch from FOLFIRINOX to gemcitabine/nab-paclitaxel (GA) as NT for PDAC. METHODS: We identified patients at a single institution switched from FOLFIRINOX to GA within the first 4 months of NT for PDAC during 2012-2017. We compared clinicopathologic data and oncologic outcomes. RESULTS: Of 25 patients who met the criteria, 21 showed a serologic or radiographic response to GA; 11 (52%) reached resection. Responders had decreased carbohydrate antigen (CA) 19-9 levels from pretreatment to post-GA (P = 0.036). Resected responders had significantly decreased CA 19-9 comparing preswitch to post-GA (P = 0.048). The only predictor of GA response was prechemotherapy CA 19-9 of less than1000 U/mL (P = 0.021). Predictors of reaching resection were head/uncinate tumor (P = 0.010) and presenting stage lower than locally advanced (P = 0.041). CONCLUSIONS: When patients do not respond to neoadjuvant FOLFIRINOX, early switch to GA should be considered. Future efforts should be directed toward identifying markers that will allow correct choice of initial therapy rather than attempting to rescue patients who respond poorly to first-line therapy.

Physical activity and exercise during preoperative pancreatic cancer treatment.

PURPOSE: Guidelines recommend exercise to cancer survivors, but limited data exists regarding exercise among patients undergoing preoperative cancer treatment. We examined differences in weekly self-reported exercise and accelerometer-measured physical activity among participants in a home-based exercise program administered during preoperative treatment for pancreatic cancer. METHODS: Participants were encouraged to perform at least 60 min/week of moderate-intensity aerobic exercise and at least 60 min/week of full-body strengthening exercises concurrent with chemotherapy, chemoradiation therapy or both sequentially and received resistance equipment, program instruction, and biweekly follow-up calls to encourage adherence. Self-reported aerobic and strengthening exercise minutes were measured using daily logs, and physical activity was measured objectively using accelerometers. RESULTS: Fifty participants (48% female, mean age 66 ± 8 years) participated for an average of 16 ± 9 preoperative weeks. Participants reported overall means of 126 ± 83 weekly minutes of aerobic exercise and 39 ± 33 weekly minutes of strengthening exercise in daily logs. Participants performed 158.7 ± 146.7 weekly minutes of accelerometer-measured moderate-to-vigorous physical activity. There were no significant differences in exercise or physical activity between treatment phases. CONCLUSIONS: These findings suggest that it is feasible to target the entire preoperative course for exercise prescription. Although participants exceeded aerobic exercise recommendations on average, we observed low strengthening exercise adherence and wide variability in self-reported exercise and accelerometer physical activity variables. These findings suggest that additional support, including program adaptations, may be necessary to overcome barriers to exercise or improve motivation when prescribing exercise in this clinical scenario.

High Prevalence of Hereditary Cancer Syndromes and Outcomes in Adults with Early-Onset Pancreatic Cancer.

Introduction: We aimed to determine the prevalence and landscape of germline mutations among patients with young-onset pancreatic ductal adenocarcinoma (PDAC) as well as their influence in prognosis.Methods: Patients from two cohorts were studied, the high-risk cohort (HRC), which included 584 PDAC patients who received genetic counseling at The University of Texas MD Anderson Cancer Center, and a general cohort (GC) with 233 metastatic PDAC patients. We defined germline DNA sequencing on 13 known pancreatic cancer susceptibility genes. The prevalence and landscape of mutations were determined, and clinical characteristics including survival were analyzed.Results: A total of 409 patients underwent genetic testing (277 from HRC and 132 from GC). As expected, the HRC had higher prevalence of germline mutations compared with the GC: 17.3% versus 6.81%. The most common mutations in both cohorts were in BRCA1/2 and mismatch-repair (MMR) genes. Patients younger than 60 years old had significantly higher prevalence of germline mutations in both the HRC [odds ratios (OR), 1.93 ± 1.03-3.70, P = 0.039] and GC (4.78 ± 1.10-32.95, P = 0.036). Furthermore, PDAC patients with germline mutations in the GC had better overall survival than patients without mutations (HR, 0.44; 95% CI of HR, 0.25-0.76, P = 0.030).Discussion: Germline mutations are highly prevalent in patients with PDAC of early onset and can be predictive of better outcomes. Considering emerging screening strategies for relatives carrying susceptibility genes as well as impact on therapy choices, genetic counseling and testing should be encouraged in PDAC patients, particularly those of young onset. Cancer Prev Res; 11(11); 679-86. ©2018 AACR.

Randomized, phase I/II study of gemcitabine plus IGF-1R antagonist (MK-0646) versus gemcitabine plus erlotinib with and without MK-0646 for advanced pancreatic adenocarcinoma.

BACKGROUND: Binding of insulin-like growth factor-I (IGF-1) to its receptor (IGF-1R) initiates downstream signals that activate PI3K/Akt/mTOR and MEK/Erk pathways, which stimulate cancer cell proliferation and induce drug resistance. Cross talk between IGF-1R and epidermal growth factor receptor (EGFR) mediates resistance to anti-EGFR agents. We studied safety, tolerability, and outcomes of MK-0646, IGF-1 monoclonal antibody, in combination with gemcitabine (G) ± erlotinib (E) in metastatic pancreatic cancer. METHODS: Our study included a phase I dose escalation and phase II randomization and expansion cohorts. A 3 + 3 dose escalation protocol was used to determine MK-0646 maximum tolerable dose (MTD) in combination with G ± E standard doses. For phase II, patients were randomized to arm A (G + MK), arm B (G + MK + E), or arm C (G + E). Primary endpoint was progression-free survival (PFS). Secondary endpoints were overall survival (OS), disease control rate, toxicity, and correlation between OS and IGF-1 in patients treated with MK-0646. RESULTS: MK-0646 MTD was 10 mg/kg in combination with G and 5 mg/kg in combination with G + E. In randomization cohort, 15 patients were treated in each arm. Disease control rates were 50, 60, and 40% respectively. PFS was not different between the three arms. OS was significantly different between arm A (10.4 months) and C (5.7 months) (P = 0.02). However, addition of erlotinib in arm B yielded no OS benefit compared to arm A (P = 0.6). Plasma and tissue IGF-1 levels did not correlate with OS (P = 0.64, 0.87). Grade 3-4 toxicity during phase II cohorts were neutropenia (10/arm A, 14/arm B, 5/arm C), leukopenia (5/A, 5/B, 7/C), thrombocytopenia (8/A, 9/B, 2/C), hyponatremia (1/A, 3/B), and hyperglycemia (8/A, 1/B). CONCLUSIONS: MK-0646 was tolerable in combination with G and associated with improvement in OS but not PFS as compared with G + E. Tissue and serum IGF-1 did not correlate with clinical outcome. TRIAL REGISTRATION: This trial is registered in ClinicalTrial.gov under the Identifier NCT00769483 and registration date was October 9, 2008.

Medical oncology and pancreatic cancer: what the radiologist needs to know.

The majority of PCs present as advanced disease, and treatment goals are for prolongation of life and palliation of the symptoms. Oncologists rely on our radiology colleagues to provide information on the extent of disease and the effectiveness of our treatment. The stakes rise in those patients where the disease has seemingly not spread and who might be treated with a goal of cure. For this subset of patients, medical oncologists and surgeons require as precise a radiologic description as possible in order to most accurately characterize the extent of the disease, in turn informing us as to the likelihood of a successful surgery and potential cure. In this paper, we review the fine points of imaging that distinguish resectable from borderline or unresectable patients, explain the principles of neoadjuvant and adjuvant therapy for pancreatic cancer, highlight some of the novel therapies now being pioneered in pancreatic cancer, and review radiologic features important for palliative care in patients with these tumors.

Outcomes of phase I clinical trials for patients with advanced pancreatic cancer: update of the MD Anderson Cancer Center experience.

BACKGROUND: In 2011, we reported the outcomes of pancreatic cancer (PC) patients enrolled in phase I trials at our institution from 2004 through 2009. At the time, gemcitabine and erlotinib were the only Food and Drug Administration-approved drugs for PC and median overall survival (OS) from consultation in the phase I clinic was 5 months. We sought to determine the impact of novel therapeutics on PC patients in phase I trials. METHODS: We reviewed records of PC patients treated in phase I trials at our institution from January 2009 through December 2014. Survival was analyzed using the Kaplan-Meier method. RESULTS: Ninety-five patients were identified. The median age was 61 years (range, 40-84), 59% were men, and 41% had stage IV disease. The median OS from consultation in the phase I clinic was 5.8 months (95% confidence interval [CI], 4.5-6.8), and the 1-year OS rate was 9% (95% CI, 4%-17%). Three patients had partial responses and 18 had stable disease ≥ 4 months. CONCLUSION: We observed no improvement in OS between PC patients enrolled in phase I trials in 2004-2009 and 2009-2015. To substantially improve OS in this challenging disease, improved patient selection and science-driven, innovative trial designs will be key.

FBXW7 missense mutation: a novel negative prognostic factor in metastatic colorectal adenocarcinoma.

BACKGROUND: FBXW7 functions as a ubiquitin ligase tagging multiple dominant oncogenic proteins and commonly mutates in colorectal cancer. Data suggest missense mutations lead to greater loss of FBXW7 function than other gene aberrations do. However, the clinicopathologic factors and outcomes associated with FBXW7 missense mutations in metastatic colorectal cancer (mCRC) have not been described. METHODS: Data were obtained from mCRC patients whose tumors were evaluated by next-generation sequencing for hotspot mutations at The University of Texas MD Anderson Cancer Center. Alterations in FBXW7 were identified, and their associations with clinicopathologic features and overall survival (OS) were evaluated. RESULTS: Of 855 mCRC patients, 571 had data on FBXW7 status; 43 (7.5%) had FBXW7 mutations, including 37 with missense mutations. R465C mutations in exon 9 were the most common missense mutations (18.6%). PIK3CA mutations were associated with FBXW7 missense mutations (p=0.012). On univariate analysis, patients with FBXW7 missense mutations had significantly worse OS (median 28.7 mo) than those with wild-type FBXW7 (median 46.6 mo; p=0.003). On multivariate analysis including other known prognostic factors such as BRAF mutations, FBXW7 missense mutations were the strongest negative prognostic factor for OS (hazard ratio 2.0; p=0.003). CONCLUSIONS: In the largest clinical dataset of mCRC to date, FBXW7 missense mutations showed a strong negative prognostic association.

Association of SMAD4 mutation with patient demographics, tumor characteristics, and clinical outcomes in colorectal cancer.

SMAD4 is an essential mediator in the transforming growth factor-ß pathway. Sporadic mutations of SMAD4 are present in 2.1-20.0% of colorectal cancers (CRCs) but data are limited. In this study, we aimed to evaluate clinicopathologic characteristics, prognosis, and clinical outcome associated with this mutation in CRC cases. Data for patients with metastatic or unresectable CRC who underwent genotyping for SMAD4 mutation and received treatment at The University of Texas MD Anderson Cancer Center from 2000 to 2014 were reviewed. Their tumors were sequenced using a hotspot panel predicted to cover 80% of the reported SMAD4 mutations, and further targeted resequencing that included full-length SMAD4 was performed on mutated tumors using a HiSeq sequencing system. Using The Cancer Genome Atlas data on CRC, the characteristics of SMAD4 and transforming growth factor-ß pathway mutations were evaluated according to different consensus molecular subtypes of CRC. Among 734 patients with CRC, 90 (12%) had SMAD4 mutations according to hotspot testing. SMAD4 mutation was associated with colon cancer more so than with rectal cancer (odds ratio 2.85; p<0.001), female sex (odds ratio 1.71; p = 0.02), and shorter overall survival than in wild-type SMAD4 cases (median, 29 months versus 56 months; hazard ratio 2.08; p<0.001 [log-rank test]). SMAD4 mutation was not associated with age, stage at presentation, colonic location, distant metastasis, or tumor grade. A subset of patients with metastatic CRC (n = 44) wild-type for KRAS, NRAS, and BRAF who received anti-epidermal growth factor receptor therapy with mutated SMAD4 (n = 13) had shorter progression-free survival duration than did patients wild-type for SMAD4 (n = 31) (median, 111 days versus 180 days; p = 0.003 [log-rank test]). Full-length sequencing confirmed that missense mutations at R361 and P356 in the MH2 domain were the most common SMAD4 alterations. In The Cancer Genome Atlas data, SMAD4 mutation frequently occurred with KRAS, NRAS, and BRAF mutations and was more common in patients with the consensus molecular subtype 3 of CRC than in those with the other 3 subtypes. This is one of the largest retrospective studies to date characterizing SMAD4 mutations in CRC patients and demonstrates the prognostic role and lack of response of CRC to anti-epidermal growth factor receptor therapy. Further studies are required to validate these findings and the role of SMAD4 mutation in CRC.

Dual Inhibition of EGFR and c-Src by Cetuximab and Dasatinib Combined with FOLFOX Chemotherapy in Patients with Metastatic Colorectal Cancer.

Purpose: Aberrant activation of the intracellular tyrosine kinase Src has been implicated as a mechanism of acquired chemotherapy resistance in metastatic colorectal cancer (mCRC). Here, the oral tyrosine kinase Src inhibitor, dasatinib, was investigated in combination with FOLFOX and cetuximab.Experimental Design: We performed a phase IB/II study of 77 patients with previously treated mCRC. Primary objectives were to determine the maximum tolerated dose, dose-limiting toxicities (DLT), pharmacodynamics, and efficacy. Using a 3 + 3 design, patients received FOLFOX6 with cetuximab and escalating doses of dasatinib (100, 150, 200 mg daily), followed by a 12-patient expansion cohort at 150 mg. Phase II studies evaluated FOLFOX plus dasatinib 100 mg in KRAS c12/13mut patients or in combination with cetuximab if KRAS c12/13WT FAK and paxillin were utilized as surrogate blood biomarkers of Src inhibition, and paired biopsies of liver metastases were obtained in patients in the expansion cohort.Results: In phase IB, the DLTs were grade 3/4 fatigue (20%) and neutropenia (23%). In phase II, grade 3/4 fatigue (23%) and pleural effusions (11%) were present. Response rates were 20% (6 of 30) in the phase IB escalation and expansion cohort and 13% (3 of 24) and 0% (0 of 23) in the KRAS c12/13WT and mutant cohorts of phase II, respectively. Median progression-free survival was 4.6, 2.3, and 2.3 months, respectively. There was no evidence of Src inhibition based on surrogate blood biomarkers or paired tumor biopsies.Conclusions: The combination of dasatinib plus FOLFOX with or without cetuximab showed only modest clinical activity in refractory colorectal cancer. This appears to be primarily due to a failure to fully inhibit Src at the achievable doses of dasatinib. The combination of dasatinib plus FOLFOX with or without cetuximab did not show meaningful clinical activity in refractory colorectal cancer due to failure to fully inhibit Src. Clin Cancer Res; 23(15); 4146-54. ©2017 AACR.