Personalized Antibodies for Gastroesophageal Adenocarcinoma (PANGEA): A Phase II Study Evaluating an Individualized Treatment Strategy for Metastatic Disease

The one-year and median overall survival (mOS) rates of advanced gastroesophageal adenocarcinomas (GEA) are ∼50% and <12 months, respectively. Baseline spatial and temporal molecular heterogeneity of targetable alterations may be a cause of failure of targeted/immunooncologic therapies. This heterogeneity, coupled with infrequent incidence of some biomarkers, has resulted in stalled therapeutic progress. We hypothesized that a personalized treatment strategy, applied at first diagnosis then serially over up to three treatment lines using monoclonal antibodies combined with optimally sequenced chemotherapy, could contend with these hurdles. This was tested using a novel clinical expansion-platform type II design with a survival primary endpoint. Of 68 patients by intention-to-treat, the one-year survival rate was 66% and mOS was 15.7 months, meeting the primary efficacy endpoint (one-sided P = 0.0024). First-line response rate (74%), disease control rate (99%), and median progression-free survival (8.2 months) were superior to historical controls. The PANGEA strategy led to improved outcomes warranting a larger randomized study. SIGNIFICANCE: This study highlights excellent outcomes achieved by individually optimizing chemotherapy, biomarker profiling, and matching of targeted therapies at baseline and over time for GEA. Testing a predefined treatment strategy resulted in improved outcomes versus historical controls. Therapeutic resistance observed in correlative analyses suggests that dual targeted inhibition may be beneficial.This article is highlighted in the In This Issue feature, p. 211.

Obtaining Knowledge in Pathology Reports Through a Natural Language Processing Approach With Classification, Named-Entity Recognition, and Relation-Extraction Heuristics

PURPOSE

Robust institutional tumor banks depend on continuous sample curation or else subsequent biopsy or resection specimens are overlooked after initial enrollment. Curation automation is hindered by semistructured free-text clinical pathology notes, which complicate data abstraction. Our motivation is to develop a natural language processing method that dynamically identifies existing pathology specimen elements necessary for locating specimens for future use in a manner that can be re-implemented by other institutions.

PATIENTS AND METHODS

Pathology reports from patients with gastroesophageal cancer enrolled in The University of Chicago GI oncology tumor bank were used to train and validate a novel composite natural language processing-based pipeline with a supervised machine learning classification step to separate notes into internal (primary review) and external (consultation) reports; a named-entity recognition step to obtain label (accession number), location, date, and sublabels (block identifiers); and a results proofreading step.

RESULTS

We analyzed 188 pathology reports, including 82 internal reports and 106 external consult reports, and successfully extracted named entities grouped as sample information (label, date, location). Our approach identified up to 24 additional unique samples in external consult notes that could have been overlooked. Our classification model obtained 100% accuracy on the basis of 10-fold cross-validation. Precision, recall, and F1 for class-specific named-entity recognition models show strong performance.

CONCLUSION

Through a combination of natural language processing and machine learning, we devised a re-implementable and automated approach that can accurately extract specimen attributes from semistructured pathology notes to dynamically populate a tumor registry.

Personalized antibodies for gastroesophageal adenocarcinoma (PANGEA): Secondary and final primary efficacy analyses

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Background: Targeted therapies (tx) have had limited benefit in advanced (aGEA) due to baseline spatial (primary vs metastatic tumor PT/MT) & temporal molecular heterogeneity (BMH/TMH). We previously reported PANGEA methods & results: 35% BMH rate & 10 OS results achieving 1yr OS of 66% & mOS of 16.4 months (m) using the personalized tx strategy (Catenacci et al. GI ASCO 2020 Abstr356). Here we will report the TMH rates at progressive disease points (PD1 & PD2), ORR/PFS/DCR in each of 3 tx lines, time to strategy failure (TTF), & updated OS/safety. Methods: PANGEA enrolled newly diagnosed aGEA pts who then received up to 3 cytotoxic (cx) tx lines (L). Baseline tissue biomarker profiling (BP) was mandated on PT/MT & PD1/PD2, & ctDNA analysis throughout. After initiating 1L cx & upon learning MT BP results, antibody (AN) was added by a predefined prioritized tx algorithm incorporating tissue & blood BP (Table). At PD1, pts went to 2L cx + initial AN. Upon results of PD1 BP, pts changed AN only if BP evolved per tx algorithm. The same was done at PD2. The 10 endpoint was 1yr OS; enrolling 68 pts provided 80% power to detect a 63% 1yr OS compared to historical 50% 1yr OS (HR 0.67), using a 1-sided test (0.10 alpha). Results: 80 pts were enrolled, & 68 tx’d per protocol. At data cut-off 2/1/20, 15 pts were still on trial with only 2 of these pts on tx <12m (8 pts in 1L, 5 in 2L, 2 in 3L). All 68 pts had at least 1 dose of 1L tx, 87% 2L tx, & 36% 3L tx. AN assigned by the tx algorithm at 1L, OS, TTF, & ORR1/PFS1/DCR1 of 1L tx are shown in Table; 2L & 3L ORR/DCR outcomes will be shown. The 3yr & 4yr OS rates were 12% & 8%. TMH leading to molecular subgroup change by tx algorithm was 51% after 1L & 36% after 2L; details & results by subgroup will be provided. Any grade >3 non-heme tox thru all 3 tx lines was seen in 25% of pts. Conclusions: PANGEA showed superior 10 & 20 endpoint efficacy, even when excluding HER2- pts, compared to historical outcomes. Clinical trial information: NCT02213289 . [Table: see text]

Evaluation of the Association of Perioperative UGT1A1 Genotype-Dosed gFOLFIRINOX With Margin-Negative Resection Rates and Pathologic Response Grades Among Patients With Locally Advanced Gastroesophageal Adenocarcinoma: A Phase 2 Clinical Trial

IMPORTANCE

Patients with locally advanced gastroesophageal adenocarcinoma (ie, stage ≥T3 and/or node positive) have high rates of recurrence despite surgery and adjunctive perioperative therapies, which also have high toxicity profiles. Evaluation of pharmacogenomically dosed perioperative gFOLFIRINOX (fluorouracil, leucovorin, oxaliplatin, and UGT1A1 genotype-directed irinotecan) to optimize efficacy while limiting toxic effects may have value.

OBJECTIVE

To evaluate the coprimary end points of margin-negative (R0) resection rates and pathologic response grades (PRGs) of gFOLFIRINOX therapy among patients with locally advanced gastroesophageal adenocarcinoma.

DESIGN, SETTING, AND PARTICIPANTS

This single-group phase 2 trial, conducted at 2 academic medical centers from February 2014 to March 2019, enrolled 36 evaluable patients with locally advanced adenocarcinoma of the esophagus, gastroesophageal junction, and gastric body. Data analysis was conducted in May 2019.

INTERVENTIONS

Patients received biweekly gFOLFIRINOX (fluorouracil, 2400 mg/m2 over 46 hours; oxaliplatin, 85 mg/m2; irinotecan, 180 mg/m2 for UGT1A1 genotype 6/6, 135 mg/m2 for UGT1A1 genotype 6/7, or 90 mg/m2 for UGT1A1 genotype 7/7; and prophylactic peg-filgastrim, 6 mg) for 4 cycles before and after surgery. Patients with tumors positive for ERBB2 also received trastuzumab (6-mg/kg loading dose, then 4 mg/kg).

MAIN OUTCOMES AND MEASURES

Margin-negative resection rate and PRG.

RESULTS

A total of 36 evaluable patients (27 [78%] men; median [range] age, 66 [27-85] years; 10 [28%] with gastric body cancer; 24 [67%] with intestinal-type tumors; 6 [17%] with ERBB2-positive tumors; 19 [53%] with UGT1A1 genotype 6/6; 16 [44%] with genotype 6/7; and 1 [3%] with genotype 7/7) were enrolled. Of these, 35 (97%) underwent surgery; 1 patient (3%) died after completing neoadjuvant chemotherapy while awaiting surgery. Overall, R0 resection was achieved in 33 of 36 patients (92%); 2 patients (6%) with linitis plastica achieved R1 resection. Pathologic response grades 1, 2, and 3 occurred in 13 patients (36%), 9 patients (25%), and 14 patients (39%), respectively, and PRG 1 was observed in 11 of 24 intestinal-type tumors (46%). Median disease-free survival was 30.1 months (95% CI, 15.0 months to not reached), and median overall survival was not reached (95% CI, 8.3 months to not reached). There were no differences in outcomes by UGT1A1 genotype group. A total of 38 patients, including 2 (5%) with antral tumors, were evaluable for toxic effects. Grade 3 or higher adverse events occurring in 5% or more of patients during the perioperative cycles included diarrhea (7 patients [18%]; 3 of 19 patients [16%] with genotype 6/6; 2 of 16 patients [13%] with genotype 6/7; 2 of 3 patients [67%] with genotype 7/7), anemia (2 patients [5%]), vomiting (2 patients [5%]), and nausea (2 patients [5%]).

CONCLUSIONS AND RELEVANCE

In this study, perioperative pharmacogenomically dosed gFOLFIRINOX was feasible, providing downstaging with PRG 1 in more than one-third of patients and an R0 resection rate in 92% of patients.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02366819.

Personalized ANtibodies for GastroEsophageal Adenocarcinoma (PANGEA): Primary efficacy analysis of the phase II platform trial (NCT02213289)

356

Background: 1-yr OS is ~40% for HER2- & ~55% for HER2+ advanced (aGEA). Targeted therapies (tx) have had limited benefit due to molecular heterogeneity. Methods: This phase 2a study of a personalized tx strategy (PTS) enrolled newly diagnosed aGEA pts who then received up to 3 cytotoxic (cx) lines: first line (1L) 5FU + oxaliplatin, 2L 5FU + irinotecan & 3L 5FU + docetaxel. Baseline biomarker profiling (BP) was mandated on primary & metastatic tumors (PT/MT) & progressive disease points (PD1, PD2). Assigned antibody (AN) was added to cx by a predefined prioritized tx algorithm (PTA) (Table) based on the MT BP. At PD1, pts went to 2L cx + initial AN. Upon results of PD1 BP, pts changed AN only if BP evolved per PTA. The same was done at PD2. If AN was unavailable (MET/FGFR2), these pts were tx’d with cx alone (not ITT). The 10 endpt was 1-yr OS of the PTS. Assuming historical 50% 1-yr OS for all aGEA pts, 68 pts tx’d per protocol PTS provided 80% power to detect an HR=0.67, corresponding to a 1-yr OS rate of 63% (under exponential survival), using a 1-sided test at the 0.10 alpha level. 20 endpts: safety, feasibility, PT/MT BP discordance at baseline & over tx line, & OS/PFS/ORR by tx line & BP group. Results: Between 6/2015-5/2019, 80 consecutive pts enrolled at 3 sites: ECOG PS 0-2 40/33/7; Male 80%; median age 60, range 28-81, peritoneal disease 36%. AN assigned by PTA at 1L & 1-yr OS are shown (Table). PT/MT discordance was 37%. Of 68 pts treated by PTS ITT, the 1-yr OS was 69.4% (p<0.001). The mOS was 16.4m [95%CI 13.8-20.8]. Any grade >3 tox thru all 3 tx lines was seen in 32% of pts. 20 analyses will be presented. Conclusions: PANGEA was feasible & met its 10 efficacy objective with observed 1-yr OS of 69.4%, meriting a randomized study. Clinical trial information: NCT02213289 . U.S. National Institutes of Health.[Table: see text]

Circulating Tumor DNA Sequencing Analysis of Gastroesophageal Adenocarcinoma

PURPOSE

Gastroesophageal adenocarcinoma (GEA) has a poor prognosis and few therapeutic options. Utilizing a 73-gene plasma-based next-generation sequencing (NGS) cell-free circulating tumor DNA (ctDNA-NGS) test, we sought to evaluate the role of ctDNA-NGS in guiding clinical decision-making in GEA.

EXPERIMENTAL DESIGN

We evaluated a large cohort (n = 2,140 tests; 1,630 patients) of ctDNA-NGS results (including 369 clinically annotated patients). Patients were assessed for genomic alteration (GA) distribution and correlation with clinicopathologic characteristics and outcomes.

RESULTS

Treatment history, tumor site, and disease burden dictated tumor-DNA shedding and consequent ctDNA-NGS maximum somatic variant allele frequency. Patients with locally advanced disease having detectable ctDNA postoperatively experienced inferior median disease-free survival (P = 0.03). The genomic landscape was similar but not identical to tissue-NGS, reflecting temporospatial molecular heterogeneity, with some targetable GAs identified at higher frequency via ctDNA-NGS compared with previous primary tumor-NGS cohorts. Patients with known microsatellite instability-high (MSI-High) tumors were robustly detected with ctDNA-NGS. Predictive biomarker assessment was optimized by incorporating tissue-NGS and ctDNA-NGS assessment in a complementary manner. HER2 inhibition demonstrated a profound survival benefit in HER2-amplified patients by ctDNA-NGS and/or tissue-NGS (median overall survival, 26.3 vs. 7.4 months; P = 0.002), as did EGFR inhibition in EGFR-amplified patients (median overall survival, 21.1 vs. 14.4 months; P = 0.01).

CONCLUSIONS

ctDNA-NGS characterized GEA molecular heterogeneity and rendered important prognostic and predictive information, complementary to tissue-NGS.See related commentary by Frankell and Smyth, p. 6893.

Perioperative (P) UGT1A1 genotype guided irinotecan (iri) dosing ‘gFOLFIRINOX’ for gastroesophageal adenocarcinoma (GEA)

4050

Background: Complete resection (R0) and pathologic response grade (PRG) correlate with long-term GEA outcome. FOLFIRINOX demonstrated efficacy in advanced GEA; gFOLFIRINOX improved tolerability. We evaluated R0, PRG and tolerability in this pilot P study. Methods: Gastric body (GB) + esophagogastric (EGJ) GEA patients (pts) with ≥T3Nx or TxN+ were enrolled & treated with 4 pre + 4 postoperative biweekly cycles of gFOLFIRINOX (5-FU 2400mg/m2 over 46 hrs; oxaliplatin 85mg/m2; iri: 180mg/m2 for UGT1A1 genotype 6/6, 135mg/m2 for 6/7, 90mg/m2 for 7/7) (+ trastuzumab (T) 6mg/kg then 4mg/kg for HER2+) with prophylactic peg-filgastrim. 1°endpoint R0 resection required 36 pts to assess for a 90% R0 rate (intention to treat (ITT)) with 90% power + 0.05 alpha; ≥30/36 R0 considered positive. Co-1°endpoint was PRG (Becker); 36 pts provided 85% power with 0.05 alpha for a complete (pCR G1a) rate of 16%. 2°endpoints were safety/toxicity, PET response, & R0/PRG by tumor site, histologic subtype, HER2 status, & UGT1A1 genotype. We report efficacy and toxicity data from the neoadjuvant (Neo) portion of the study; postop data & survival outcomes will be presented at the meeting. Results: 4 sites enrolled 36 ITT pts between 2/2014-8/2018; 75% male, median age 66 (range 27-85). All pts completed all 4 cycles of Neo therapy: 10% had any dose reduction of iri (16%/0%/25% by genotype 6/6, 6/7, 7/7); any G3+ toxicity occurred in 35% of pts (32% 6/6, 29% 6/7, 75% 7/7). G3+ toxicity in ≥5% of pts: diarrhea (17.5%; 6/6 21%, 6/7 11%, 7/7 25%), anemia (5%), vomiting (5%). Efficacy is shown in the Table. Of pts going to surgery, both R1 resections were GB linitus. PRG1(a+b) was achieved in 36% of ITT pts, 46% of intestinal type histology. Conclusions: Neo gFOLFIRINOX was tolerable with surrogate efficacy comparable to FLOT. Clinical trial information: NCT02366819. [Table: see text]

Suspected and confirmed germline variants from tumor-only somatic sequencing of 864 gastrointestinal malignancies

e13131

Background: Targeted tumor-only somatic sequencing informs therapies and is becoming a routine part of cancer care. It also identifies patients with possible germline variants who require confirmatory genetic testing. The aim was to identify patients with suspected and confirmed germline variants whose GI tumors underwent somatic sequencing. Methods: 864 patients with GI tumors who had Foundation One (FO) somatic sequencing from 4/2003-3/2018 were evaluated. Inclusion criteria for suspected germline variants were: a) allele frequency ≥ 35% in hereditary cancer genes and b) pathogenic variants by FO and/or ClinVar. Variants in commonly mutated somatic genes ( TP53, KRAS, CDKN2A) were excluded in patients over age 40. Recommendation of genetic evaluation and germline test results were recorded. Patient, family, and tumor characteristics were compared using univariate analysis. Results: 199 of 864 patients had suspected germline pathogenic variants. 50 patients were recommended genetic evaluation, and 26 patients underwent genetic testing. A germline pathogenic variant was confirmed in 15 patients. Among all patients suspected to have germline variants, 8% were confirmed by genetic testing. Patients under age 40 and those with family cancer history were more often referred for testing (Table). Patients with variants in BRCA1, MLH1, MSH2, PMS2, POLE and TP53 were more often referred for testing. Conclusions: A quarter of patients carried a somatic pathogenic variant with allele frequency ≥35% in a hereditary cancer gene. 25% of these patients were recommended for genetic evaluation. Younger patients and those with family history were more often referred. 8% of patients with suspected germline variants were confirmed by genetic testing. These results provide “real world” experience in using somatic only tumor testing to identify patients with germline pathogenic variants who then might benefit from future cancer screening and genetic testing in family members. Comparison of characteristics by recommendation to undergo genetic testing based on somatic tumor sequencing results. [Table: see text]

Initial Report of Second-Line FOLFIRI in Combination with Ramucirumab in Advanced Gastroesophageal Adenocarcinomas: A Multi-Institutional Retrospective Analysis

BACKGROUND

The randomized phase III RAINBOW trial established paclitaxel (pac) plus ramucirumab (ram) as a global standard for second-line (2L) therapy in advanced gastric and gastroesophageal junction adenocarcinoma, together gastroesophageal adenocarcinoma (GEA). Patients (pts) receiving first-line (1L) FOLFOX often develop neuropathy that renders continued neurotoxic agents in the 2L setting unappealing and other regimens more desirable. As such, FOLFIRI-ram has become an option for patients with 2L GEA. FOLFIRI-ramucirumab (ram) has demonstrated safety and activity in 2L colorectal cancer, but efficacy/safety data in GEA are lacking.

SUBJECTS, MATERIALS, AND METHODS

Patients with GEA treated with 2L FOLFIRI-ram between August 2014 and April 2018 were identified. Clinicopathologic data including oxaliplatin neurotoxicity rates/grades (G), 2L treatment response, progression-free survival (PFS), overall survival (OS), safety, and molecular features were abstracted from three U.S. academic institutions. Kaplan-Meier survival analysis was used to generate PFS/OS; the likelihood ratio test was used to determine statistical significance.

RESULTS

We identified 29 pts who received 2L FOLFIRI-ram. All pts received 1L platinum + fluoropyrimidine, and 23 of 29 (79%) had post-1L neuropathy; 12 (41%) had G1, and 11 (38%) had G2. Patients were evenly split between esophagus/gastroesophageal junction (12; 41%) and gastric cancer (17; 59%). Among evaluable pts (26/29), the overall response rate was 23% (all partial response) with a disease control rate of 79%. Median PFS was 6.0 months and median OS was 13.4 months among all evaluable pts. Six- and 12-month OS were 90% (n = 18/20) and 41% (n = 7/17). There were no new safety signals.

CONCLUSION

We provide the first data suggesting FOLFIRI-ram is a safe, non-neurotoxic regimen comparing favorably with the combination of pac + ram used in the seminal RAINBOW trial.

IMPLICATIONS FOR PRACTICE

Results of this study provide initial support for the safety and efficacy of second-line (2L) FOLFIRI-ramucirumab (ram) after progression on first-line platinum/fluoropyrimidine in patients with gastroesophageal adenocarcinoma (GEA). The overall response, progression-free survival, overall survival, and toxicity profile compare favorably with paclitaxel (pac) + ram and highlight the importance of the ongoing phase II RAMIRIS trial examining FOLFIRI-ram versus pac + ram in 2L GEA (NCT03081143). FOLFIRI-ram may warrant consideration for inclusion as an alternate regimen in consensus guidelines for GEA.

Targeted Therapies for Targeted Populations: Anti-EGFR Treatment for EGFR-Amplified Gastroesophageal Adenocarcinoma

Previous anti-EGFR trials in unselected patients with gastroesophageal adenocarcinoma (GEA) were resoundingly negative. We identified EGFR amplification in 5% (19/363) of patients at the University of Chicago, including 6% (8/140) who were prospectively screened with intention-to-treat using anti-EGFR therapy. Seven patients received ≥1 dose of treatment: three first-line FOLFOX plus ABT-806, one second-line FOLFIRI plus cetuximab, and three third/fourth-line cetuximab alone. Treatment achieved objective response in 58% (4/7) and disease control in 100% (7/7) with a median progression-free survival of 10 months. Pretreatment and posttreatment tumor next-generation sequencing (NGS), serial plasma circulating tumor DNA (ctDNA) NGS, and tumor IHC/FISH for EGFR revealed preexisting and/or acquired genomic events, including EGFR-negative clones, PTEN deletion, KRAS amplification/mutation, NRAS, MYC, and HER2 amplification, and GNAS mutations serving as mechanisms of resistance. Two evaluable patients demonstrated interval increase of CD3+ infiltrate, including one who demonstrated increased NKp46+, and PD-L1 IHC expression from baseline, suggesting an immune therapeutic mechanism of action. EGFR amplification predicted benefit from anti-EGFR therapy, albeit until various resistance mechanisms emerged.Significance: This paper highlights the role of EGFR inhibitors in EGFR-amplified GEA-despite negative results in prior unselected phase III trials. Using serial ctDNA and tissue NGS, we identified mechanisms of primary and acquired resistance in all patients, as well as potential contribution of antibody-dependent cell-mediated cytotoxicity to their clinical benefit. Cancer Discov; 8(6); 696-713. ©2018 AACR.See related commentary by Strickler, p. 679This article is highlighted in the In This Issue feature, p. 663.

Circulating tumor DNA (ctDNA) landscape and prognostic implications in advanced gastroesophageal adenocarcinoma (GEC)

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Background: Esophagogastric junction (EGJ) and gastric (GC) cancer, together GEA, have a poor prognosis, high molecular heterogeneity, and few targeted therapeutic options. Guardant360 is a clinical gene panel test for next generation sequencing (NGS) of plasma circulating tumor (ct) DNA. Methods: We evaluated a large cohort of ctDNA-derived genomic results (Guardant Health, Inc.), including a subset of pts from the University of Chicago (UC) with clinical data. GEA pts in these 2 cohorts were assessed for genomic alteration (GA) distribution: mutations (mt), indels, amplifications (amp) and fusions. UC survival analyses were performed using log-rank test and select gene-by-gene alteration frequency by pt with chi-square comparisons. Results: The overall ctDNA cohort comprised 1128 pts with median age 64 yrs (range 19-98) and 73% males. At least 1 detectable GA (median 4, range 0-102) was observed in 870 pts (77%). The UC subset of pts (n=171), median age 63 yrs (range 19-87), included 2/10/27/61% stage I/II/III/IV, 77/13/5/5% Caucasian/African American/Asian/Hispanic, 74% male and 63% EGJ. At least 1 detectable GA (median 4, range 1-102) was observed in 157 pts; median GAs per test by stage I vs II/III vs IV was 1.5/3.5/4.5. GA distributions were similar to the larger cohort (Table 1). Stage IV pts tested within 6 weeks of diagnosis/recurrence (n=34) had a median survival of 8.7 months. In these pts, BRAF/ FGFR2 amps and ARAF mts were each prognostic for worse survival ( p<0.05), and MET and KRAS amps trended towards significance. Mt allele frequency (MAF) ctDNA burden inversely correlated with survival ( p=0.01) . In 138 pts with ≥2 serial tests, non-synonymous GAs in MET, PIK3CA, and FGFR1 were more commonly late events (all p<0.05 ). Conclusions: GAs in plasma ctDNA were detected in 77% of GEA pts including numerous actionable targets. ctDNA analysis merits further evaluation as a prognostic biomarker assessing specific genes, overall ctDNA burden, and molecular heterogeneity at baseline and serially. [Table: see text]

Personalized antibodies for gastroesophageal adenocarcinoma (PANGEA): A phase II precision medicine trial (NCT02213289)

TPS198

Background: Targeted therapies (tx) in GEA have had limited efficacy despite recognition of numerous ‘targetable’ molecular events. This may be due to the molecular heterogeneity (MH) that exists between patients (pts), within the primary tumor (PT), between PT and synchronous metastatic lesions (MLs), and in lesions over time. Current biomarker profiling (BP) is performed on one site, usually the PT, yet this fails to capture the MH of GEA, with likely major clinical implications. Classic trial designs are challenged by MH, low frequency oncogenic drivers, and scarcity of tissue. There is need for novel trial designs and BP technologies that address these concerns, provide tx algorithms for pts with multiple aberrations, and have access to several txs. Methods: This phase IIa, open-label, non-randomized ‘platform trial’ enrolls pts with newly diagnosed metastatic GEA or recurrent disease after curative-intent surgery. Baseline tumor BP is performed on PT/ML along with circulating free (cf)DNA. Pts receive first line (1L) mFOLFOX6 + biologic tx based on BP of the ML using a prioritized tx algorithm (HER2+: trastuzumab; MET+: none; FGFR2+: none; EGFR+: ABT806; MSI-H: nivolumab; ‘RAS-like’: ramucirumab). MET/FGFR2 arms (~10% of all pts) are tx’d with cytotoxics only and followed for natural outcome until/if tx becomes available on study. At first progression (PD1), pts undergo biopsy of growing ML and change to 2L FOLFIRI + biologic agent as assigned in 1L tx. Upon results of PD1 biopsy, pts change to a new biologic tx if the molecular category evolves. At PD2, pts change to 3L FOLTAX + biologic as determined after PD1, and switch biologic tx from PD2 biopsy result. All PD1/PD2 tumor/cfDNA samples undergo BP to assess evolution and resistance mechanisms. Co-primary endpoints: safety, feasibility, and overall survival (OS) of this personalized treatment strategy (excluding MET/FGFR2) compared to historical controls (HR 0.66). Secondary endpoints include rate of baseline MH between PT and ML leading to new treatment assignment; utility of cfDNA; overall progression-free survival (PFS)/response rate (RR); OS/PFS/RR in each targetable group. Since 8/2015, 38 of 68 planned pts have been accrued. Clinical trial information: NCT02213289.

Genomic Heterogeneity as a Barrier to Precision Medicine in Gastroesophageal Adenocarcinoma

Gastroesophageal adenocarcinoma (GEA) is a lethal disease where targeted therapies, even when guided by genomic biomarkers, have had limited efficacy. A potential reason for the failure of such therapies is that genomic profiling results could commonly differ between the primary and metastatic tumors. To evaluate genomic heterogeneity, we sequenced paired primary GEA and synchronous metastatic lesions across multiple cohorts, finding extensive differences in genomic alterations, including discrepancies in potentially clinically relevant alterations. Multiregion sequencing showed significant discrepancy within the primary tumor (PT) and between the PT and disseminated disease, with oncogene amplification profiles commonly discordant. In addition, a pilot analysis of cell-free DNA (cfDNA) sequencing demonstrated the feasibility of detecting genomic amplifications not detected in PT sampling. Lastly, we profiled paired primary tumors, metastatic tumors, and cfDNA from patients enrolled in the personalized antibodies for GEA (PANGEA) trial of targeted therapies in GEA and found that genomic biomarkers were recurrently discrepant between the PT and untreated metastases. Divergent primary and metastatic tissue profiling led to treatment reassignment in 32% (9/28) of patients. In discordant primary and metastatic lesions, we found 87.5% concordance for targetable alterations in metastatic tissue and cfDNA, suggesting the potential for cfDNA profiling to enhance selection of therapy.Significance: We demonstrate frequent baseline heterogeneity in targetable genomic alterations in GEA, indicating that current tissue sampling practices for biomarker testing do not effectively guide precision medicine in this disease and that routine profiling of metastatic lesions and/or cfDNA should be systematically evaluated. Cancer Discov; 8(1); 37-48. ©2017 AACR.See related commentary by Sundar and Tan, p. 14See related article by Janjigian et al., p. 49This article is highlighted in the In This Issue feature, p. 1.

Molecular profiling of advanced pancreatic cancer (PC) patients from a phase I/II study using circulating tumor DNA

4124

Background: PC has a poor prognosis with a 5-year survival of 9%. Targeted therapies have yet to demonstrate improved outcomes in this disease. Circulating tumour DNA (ctDNA) may be used as a non-invasive method for the detection and quantification of genomic abnormalities. We performed a retrospective-prospective study to assess molecular alterations in the ctDNA of advanced PC patients. Methods: Plasma samples were banked from patients enrolled in the previously reported Phase Ib/II trial of gemcitabine with placebo or vismodegib (NCT01064622; Catenacci et al JCO 2015). Eligible patients had unresectable PC and no prior therapy for metastatic disease. Patient samples ( < 3ml) collected pre-treatment and at regular intervals and stored for ~6-8 years were analyzed using InVision (enhanced tagged-amplicon sequencing) for “hotspot” regions of 34 genes, including KRAS (exons 2 and 3), and select full gene coverage. Results: Of 113 patients enrolled in the trial, a cohort of 72 patients were included in this study. Baseline plasma ctDNA profiling detected any genomic event in 88% of patients (SNV/indels found at range of 0.07%-23% allele fraction (AF) with 20% detected at < 0.5% AF). Patients had between 1-5 mutations (median, 2): KRAS mutations were detected in 80% of patients tested, of which 86% had concurrent KRAS/TP53 mutation(s) and 16% with concurrent KRAS/TP53/CDK2NA. Of note, 2 cases presented with IDH1 point mutations (R132C, R132H). An ERBB2 amplification and a FGFR2 amplification were detected in 2 individuals. An update on the analyses will include serial ctDNA testing during treatment and correlation with outcomes. Conclusions: ctDNA analysis of this cohort of banked PC plasma samples described the landscape of genomic aberrations at baseline and over time, including rare but potentially important actionable events including ERBB2 and FGFR2 amplifications and IDH1 mutation. We demonstrate a sensitive method for re-analysing trial outcomes, despite limiting plasma volume and time lapse since samples were collected.

Development of supported iron oxide catalyst for destruction of PCDD/F

Studies on the development of supported iron oxide catalysts for PCDD/F decomposition using 2-monochlorophenol as a surrogate test compound are presented. Iron oxide catalysts supported on titania were prepared by two methods: impregnation and the sol-gel method. The latter preparation method resulted in better dispersion of iron oxide on the surface and the formation of gamma-Fe2O3. This is in contrast to the impregnated samples where alpha-Fe2O3 crystallites were formed. Formation of gamma-Fe2O3 resulted in improved reducibility of the active phase that favorably affected the catalytic oxidation properties of the catalyst, i.e., the light-off curves for the sol-gel samples were shifted toward lower temperature. Addition of calcium oxide to iron oxide catalyst further improved the performance of the system through stabilization and increase in the concentration of gamma-Fe2O3 in the sol-gel prepared samples. Addition of calcium oxide has a dual effect on the performance of the catalyst. First, it creates oxygen vacancies in the reduction-resistant Fe2O3 octahedral structures, thereby improving the reducibility of the active phase. Second, iron oxide can transform during decomposition of chlorinated hydrocarbons into iron chloride. Calcium oxide improved the chlorine transfer from the surface iron oxide species, thereby providing a relatively fresh surface for further catalytic oxidation. Comparison of TPR profiles with the position of light-off curves in 2-monochlorophenol decomposition led to the conclusion that Fe3O4 species are the active phase under conditions that facilitate redox cycling between Fe3+ and Fe2+ ions.