Optimization of ultracentrifugation-based method to enhance the purity and proteomic profiling depth of plasma-derived extracellular vesicles and particles.

Circulating extracellular vesicles and particles (EVPs) are being investigated as potential biomarkers for early cancer detection, prognosis, and disease monitoring. However, the suboptimal purity of EVPs isolated from peripheral blood plasma has posed a challenge of in-depth analysis of the EVP proteome. Here, we compared the effectiveness of different methods for isolating EVPs from healthy donor plasma, including ultracentrifugation (UC)-based protocols, phosphatidylserine-Tim4 interaction-based affinity capture (referred to as "PS"), and several commercial kits. Modified UC methods with an additional UC washing or size exclusion chromatography step substantially improved EVP purity and enabled the detection of additional proteins via proteomic mass spectrometry, including many plasma membrane and cytoplasmic proteins involved in vesicular regulation pathways. This improved performance was reproduced in cancer patient plasma specimens, resulting in the identification of a greater number of differentially expressed EVP proteins, thus expanding the range of potential biomarker candidates. However, PS and other commercial kits did not outperform UC-based methods in improving plasma EVP purity. PS yielded abundant contaminating proteins and a biased enrichment for specific EVP subsets, thus unsuitable for proteomic profiling of plasma EVPs. Therefore, we have optimized UC-based protocols for circulating EVP isolation, which enable further in-depth proteomic analysis for biomarker discovery.

Perioperative versus total neoadjuvant chemotherapy in gastric cancer.

Background: Perioperative chemotherapy is standard of care management for locally advanced gastric cancer (GC), but a substantial proportion of patients do not complete adjuvant therapy due to postoperative complications and prolonged recovery. Administration of all chemotherapy prior to surgery in the form of total neoadjuvant therapy (TNT) may optimize complete delivery of systemic therapy. Methods: We performed a retrospective review of GC patients who had surgery at Memorial Sloan Kettering Cancer Center (MSKCC) from May 2014 to June 2020. Results: One hundred and forty-nine patients were identified; 121 patients received perioperative chemotherapy and 28 patients received TNT. TNT was chosen if patients had interim radiographic and/or clinical response to treatment. Baseline characteristics were well-balanced between the two group except for chemotherapy regimen; more TNT patients received FLOT compared to the perioperative group (79% vs. 31%). There was no difference in the proportion of patients who completed all planned cycles, but TNT patients received a higher proportion of cycles containing all chemotherapy drugs (93% vs. 74%, P<0.001). Twenty-nine patients (24%) in the perioperative group did not receive intended adjuvant therapy. There was no significant difference in hospital length of stay or surgical morbidity. The overall distribution of pathologic stage was similar between the two groups. Fourteen percent of TNT patients and 5.8% of perioperative patients achieved a pathologic complete response (P=0.6). There was no significant difference in recurrence free survival (RFS) or overall survival (OS) between the TNT and perioperative groups [24-month OS rate 77% vs. 85%, HR 1.69 (95% CI: 0.80-3.56)]. Conclusions: Our study was limited by a small TNT sample size and biases inherent to a retrospective analysis. TNT appears to be feasible in a select population, without any increase in surgical morbidity.

Clinico-genomic Characterization of ATM and HRD in Pancreas Cancer: Application for Practice.

PURPOSE: Characterizing germline and somatic ATM variants (gATMm, sATMm) zygosity and their contribution to homologous recombination deficiency (HRD) is important for therapeutic strategy in pancreatic ductal adenocarcinoma (PDAC). EXPERIMENTAL DESIGN: Clinico-genomic data for patients with PDAC and other cancers with ATM variants were abstracted. Genomic instability scores (GIS) were derived from ATM-mutant cancers and overall survival (OS) was evaluated. RESULTS: Forty-six patients had PDAC and pathogenic ATM variants including 24 (52%) stage III/IV: gATMm (N = 24), and sATMm (N = 22). Twenty-seven (59%) had biallelic, 15 (33%) monoallelic, and 4 indeterminate (8%) variants. Median OS for advanced-stage cohort at diagnosis (N = 24) was 19.7 months [95% confidence interval (CI): 12.3-not reached (NR)], 27.1 months (95% CI: 22.7-NR) for gATMm (n = 11), and 12.3 months for sATMm (n = 13; 95% CI: 11.9-NR; P = 0.025). GIS was computed for 33 patients with PDAC and compared with other ATM-mutant cancers enriched for HRD. The median was lower (median, 11; range, 2-29) relative to breast (18, 3-55) or ovarian (25, 3-56) ATM-mutant cancers (P < 0.001 and P = 0.003, respectively). Interestingly, biallelic pathogenic ATM variants were mutually exclusive with TP53. Other canonical driver gene (KRAS, CDKN2A, SMAD4) variants were less frequent in ATM-mutant PDAC. CONCLUSIONS: ATM variants in PDAC represent a distinct biologic group and appear to have favorable OS. Nonetheless, pathogenic ATM variants do not confer an HRD signature in PDAC and ATM should be considered as a non-core HR gene in this disease.

Circulating tumor and invasive cell expression profiling predicts effective therapy in pancreatic cancer.

BACKGROUND: Pancreatic adenocarcinoma (PDAC) remains a refractory disease; however, modern cytotoxic chemotherapeutics can induce tumor regression and extend life. A blood-based, pharmacogenomic, chemosensitivity assay using gene expression profiling of circulating tumor and invasive cells (CTICs) to predict treatment response was previously developed. The combination regimen of 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) and gemcitabine/nab-paclitaxel (G/nab-P) are established frontline approaches for treating advanced PDAC; however, there are no validated biomarkers for treatment selection. A similar unmet need exists for choosing second-line therapy. METHODS: The chemosensitivity assay was evaluated in metastatic PDAC patients presenting for frontline treatment. A prospective study enrolled patients (n = 70) before receiving either FOLFIRINOX or G/nab-P at a 1:1 ratio. Six milliliters of peripheral blood was collected at baseline and at time of disease progression. CTICs were isolated, gene-expression profiling was performed, and the assay was used to predict effective and ineffective chemotherapeutic agents. Treating physicians were blinded to the assay prediction results. RESULTS: Patients receiving an effective regimen as predicted by the chemosensitivity assay experienced significantly longer median progression-free survival (mPFS; 7.8 months vs. 4.2 months; hazard ratio [HR], 0.35; p = .0002) and median overall survival (mOS; 21.0 months vs. 9.7 months; HR, 0.40; p = .005), compared with an ineffective regimen. Assay prediction for effective second-line therapy was explored. The entire study cohort experienced favorable outcomes compared with historical controls, 7.1-month mPFS and 12.3-month mOS. CONCLUSIONS: Chemosensitivity assay profiling is a promising tool for guiding therapy in advanced PDAC. Further prospective validation is under way (clinicaltrials.gov NCT03033927).

PD-L1 expression and overall survival in Asian and western patients with gastric cancer.

Aim: Data are limited on PD-L1 expression and its association with overall survival (OS) in gastric cancer (GC) patients receiving routine care in different regions. Materials & methods: In a retrospective study, PD-L1 expression was assayed using the 22C3 pharmDx on GC tumor samples collected between 2003 and 2017 at South Korean and US cancer centers. PD-L1 positivity was defined as combined positive score (CPS) ≥1. The relationship between PD-L1 and OS was analyzed. Results: Of 574 GC tumor samples, 67.4% were CPS ≥1 (68.7% in Korean and 65.7% in US patients). PD-L1 expression was not associated with OS (adjusted hazard ratio: 0.94; 95% CI: 0.75-1.17). Conclusion: PD-L1 prevalence and its association with OS was similar between South Korean and US GC patients.

Phase I/Ib study of crenolanib with ramucirumab and paclitaxel as second-line therapy for advanced esophagogastric adenocarcinoma.

PURPOSE: Paclitaxel plus ramucirumab is a standard second-line regimen for patients with advanced gastric adenocarcinoma, but clinical benefit remains modest. One potential resistance mechanism to VEGFR2 inhibition is activation of the PDGF/PDGFR pathway, which can be blocked by the selective inhibitor crenolanib. Therefore, we performed a phase I/Ib study of crenolanib in combination with paclitaxel/ramucirumab. METHODS: Patients with metastatic esophagogastric adenocarcinoma refractory to first-line therapy received escalating doses of crenolanib [60 mg twice daily (BID) to 100 mg three times daily (TID)] in combination with paclitaxel 80 mg/m2 intravenously on days 1, 8 and 15 and ramucirumab 8 mg/kg intravenously on days 1 and 15 of a 28-day cycle. The primary objective was to determine the maximally tolerated dose (MTD) of crenolanib. Additional patients were enrolled in the dose expansion cohort to assess 6-month progression-free survival (PFS) at the MTD. RESULTS: We enrolled 19 patients in the dose escalation phase and 8 patients in the dose expansion phase at the MTD of crenolanib 100 mg BID. Common grade 3/4 treatment-emergent adverse events included leukopenia (19%), anemia (11%) and neutropenia (11%). In the 14 patients treated at the MTD, 6-month PFS was 43% [95% confidence interval (CI) 23-78%] and the objective response rate (ORR) was 42% (95% CI 15-72%). The trial was terminated early due to withdrawal of crenolanib by the sponsor. CONCLUSIONS: The addition of crenolanib to paclitaxel/ramucirumab is safe and well-tolerated at a dose level up to 100 mg BID. CLINICAL TRIAL REGISTRATION: NCT03193918. June 19, 2017.

Prognostic significance of T-cell-inflamed gene expression profile and PD-L1 expression in patients with esophageal cancer.

PURPOSE: The ability of the T-cell-inflamed gene expression profile (GEP) to predict clinical outcome in esophageal cancer (EC) is unknown. This retrospective observational study assessed the prognostic value of GEP and programmed death ligand 1 (PD-L1) expression in patients with EC treated in routine clinical practice. METHODS: Tumor samples of 294 patients from three centers in Denmark, South Korea, and the United States, collected between 2005 and 2017, were included. T-cell-inflamed GEP score was defined as non-low or low using a cutoff of -1.54. A combined positive score (CPS) ≥10 was defined as PD-L1 expression positivity. Associations between overall survival (OS) and GEP status and PD-L1 expression were explored by Cox proportional hazards models adjusting for age, sex, histology, stage, and performance status. RESULTS: Median age was 65 years; 63% of patients had adenocarcinoma (AC) and 37% had squamous cell carcinoma (SCC). Thirty-six percent of tumors were GEP non-low, with higher prevalence in AC (46%) than SCC (18%). Twenty-one percent were PD-L1-positive: 32% in South Korean samples versus 16% in non-Asian samples and 26% in SCC versus 18% in AC. GEP scores and PD-L1 CPS were weakly correlated (Spearman's R = 0.363). OS was not significantly associated with GEP status (non-low vs low; adjusted hazard ratio, 0.91 [95% CI, 0.69-1.19]) or PD-L1 expression status. CONCLUSION: Neither GEP nor PD-L1 expression was a prognostic marker in Asian and non-Asian patients with EC.

Pancreas cancer and BRCA: A critical subset of patients with improving therapeutic outcomes.

BACKGROUND: Patients with germline/somatic BRCA1/BRCA2 mutations (g/sBRCA1/2) comprise a distinct biologic subgroup of pancreas ductal adenocarcinoma (PDAC). METHODS: Institutional databases were queried to identify patients who had PDAC with g/sBRCA1/2. Demographics, clinicopathologic details, genomic data (annotation sBRCA1/2 according to a precision oncology knowledge base for somatic mutations), zygosity, and outcomes were abstracted. Overall survival (OS) was estimated using the Kaplan-Meier method. RESULTS: In total, 136 patients with g/sBRCA1/2 were identified between January 2011 and June 2020. Germline BRCA1/2 (gBRCA1/2) mutation was identified in 116 patients (85%). Oncogenic somatic BRCA1/2 (sBRCA1/2) mutation was present in 20 patients (15%). Seventy-seven patients had biallelic BRCA1/2 mutations (83%), and 16 (17%) had heterozygous mutations. Sixty-five patients with stage IV disease received frontline platinum therapy, and 52 (80%) had a partial response. The median OS for entire cohort was 27.6 months (95% CI, 24.9-34.5 months), and the median OS for patients who had stage IV disease was 23 months (95% CI, 19-26 months). Seventy-one patients received a poly(adenosine diphosphate ribose) polymerase (PARP) inhibitor (PARPi), and 52 received PARPi monotherapy. For maintenance PARPi, 10 patients (36%) had a partial response, 12 (43%) had stable disease, and 6 (21%) had progression of disease as their best response. Six patients (21%) received maintenance PARPi for >2 years. For those with stage IV disease who received frontline platinum, the median OS was 26 months (95% CI, 20-52 months) for biallelic patients (n = 39) and 8.66 months (95% CI, 6.2 months to not reached) for heterozygous patients (n = 4). The median OS for those who received PARPi therapy was 26.5 months (95% CI, 24-53 months) for biallelic patients (n = 25) and 8.66 months (95% CI, 7.23 months to not reached) for heterozygous patients (n = 2). CONCLUSIONS: g/sBRCA1/2 mutations did not appear to have different actionable utility. Platinum and PARPi therapies offer therapeutic benefit, and very durable outcomes are observed in a subset of patients who have g/sBRCA1/2 mutations with biallelic status.

Prevalence of Germline Alterations on Targeted Tumor-Normal Sequencing of Esophagogastric Cancer.

Importance: Among patients with esophagogastric cancers, only individuals who present with known features of heritable cancer syndromes are referred for genetic testing. Broader testing might identify additional patients with germline alterations. Objectives: To examine the prevalence of likely pathogenic or pathogenic (LP/P) germline alterations among patients with esophagogastric cancer and to assess associations between germline variant prevalence and demographic and clinicopathologic features. Design, Setting, and Participants: This cross-sectional study was performed at a tertiary referral cancer center from January 1, 2014, to December 31, 2019, in 515 patients with esophagogastric cancer who consented to tumor and blood sequencing. Main Outcomes and Measures: Presence or absence of LP/P variants in up to 88 genes associated with cancer predisposition syndromes as identified by targeted sequencing (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets). Results: Among 515 patients (median age, 59 years; range, 18-87 years; 368 [71.5%] male; 398 [77.3%] White), 243 (47.2%) had gastric cancer, 111 (21.6%) had gastroesophageal junction (GEJ) cancer, and 161 (31.3%) had esophageal cancer. A total of 48 patients with gastric cancer (19.8%), 16 (14.4%) with GEJ cancer, and 17 (10.6%) with esophageal cancer had LP/P germline variants. The number of LP/P variants in high- and moderate-penetrance genes was significantly higher in patients with gastric cancer (29 [11.9%]; 95% CI, 8.1%-16.7%) vs patients with esophageal cancer (8 [5.0%]; 95% CI, 2.2%-9.6%; P = .03), and the difference was greater for high-penetrance germline alterations in patients with gastric cancer (25 [10.3%]; 95% CI, 6.8%-14.8%) vs in patients with esophageal cancer (3 [1.9%]; 95% CI, 0.38%-5.3%; P = .001). The most frequent high- and moderate-penetrance LP/P alterations were in BRCA1/2 (14 [2.7%]), ATM (11 [2.1%]), CDH1 (6 [1.2%]), and MSH2 (4 [0.8%]). Those with early-onset disease (≤50 years of age at diagnosis) were more likely to harbor an LP/P germline variant (29 [21.0%]; 95% CI, 14.5%-28.8%) vs those with late-onset disease (patients >50 years of age at diagnosis) (52 [13.8%]; 95% CI, 10.5%-17.7%; P = .046). ATM LP/P variants occurred in 6 patients (4.3%; 95% CI, 1.6%-9.1%) with early-onset esophagogastric cancer vs 5 (1.3%; 95% CI, 0.4%-3.1%; P = .08) of those with late-onset esophagogastric cancer. Conclusions and Relevance: These results suggest that pathogenic germline variants are enriched in gastric and early-onset esophagogastric cancer and that germline testing should be considered in these populations. The role of ATM alterations in esophagogastric cancer risk warrants further investigation.

Conformation-Specific Inhibitory Anti-MMP-7 Monoclonal Antibody Sensitizes Pancreatic Ductal Adenocarcinoma Cells to Chemotherapeutic Cell Kill.

Matrix metalloproteases (MMPs) undergo post-translational modifications including pro-domain shedding. The activated forms of these enzymes are effective drug targets, but generating potent biological inhibitors against them remains challenging. We report the generation of anti-MMP-7 inhibitory monoclonal antibody (GSM-192), using an alternating immunization strategy with an active site mimicry antigen and the activated enzyme. Our protocol yielded highly selective anti-MMP-7 monoclonal antibody, which specifically inhibits MMP-7's enzyme activity with high affinity (IC50 = 132 ± 10 nM). The atomic model of the MMP-7-GSM-192 Fab complex exhibited antibody binding to unique epitopes at the rim of the enzyme active site, sterically preventing entry of substrates into the catalytic cleft. In human PDAC biopsies, tissue staining with GSM-192 showed characteristic spatial distribution of activated MMP-7. Treatment with GSM-192 in vitro induced apoptosis via stabilization of cell surface Fas ligand and retarded cell migration. Co-treatment with GSM-192 and chemotherapeutics, gemcitabine and oxaliplatin elicited a synergistic effect. Our data illustrate the advantage of precisely targeting catalytic MMP-7 mediated disease specific activity.

Early-Onset Pancreas Cancer: Clinical Descriptors, Genomics, and Outcomes.

BACKGROUND: Recent evidence suggests a rising incidence of cancer in younger individuals. Herein, we report the epidemiologic, pathologic, and molecular characteristics of a patient cohort with early-onset pancreas cancer (EOPC). METHODS: Institutional databases were queried for demographics, treatment history, genomic results, and outcomes. Overall survival from date of diagnosis was estimated using Kaplan-Meier method. RESULTS: Between 2008 and 2018, 450 patients with EOPC were identified at Memorial Sloan Kettering. Median overall survival was 16.3 (95% confidence interval [CI] = 14.6 to 17.7) months in the entire cohort and 11.3 (95% CI = 10.2 to 12.2) months for patients with stage IV disease at diagnosis. Of the patients, 132 (29.3% of the cohort) underwent somatic testing; 21 of 132 (15.9%) had RAS wild-type cancers with identification of several actionable alterations, including ETV6-NTRK3, TPR-NTRK1, SCLA5-NRG1, and ATP1B1-NRG1 fusions, IDH1 R132C mutation, and mismatch repair deficiency. A total of 138 patients (30.7% of the cohort) underwent germline testing; 44 of 138 (31.9%) had a pathogenic germline variant (PGV), and 27.5% harbored alterations in cancer susceptibility genes. Of patients seen between 2015 and 2018, 30 of 193 (15.5%) had a PGV. Among 138 who underwent germline testing, those with a PGV had a reduced all-cause mortality compared with patients without a PGV controlling for stage and year of diagnosis (hazard ratio = 0.42, 95% CI = 0.26 to 0.69). CONCLUSIONS: PGVs are present in a substantial minority of patients with EOPC. Actionable somatic alterations were identified frequently in EOPC, enriched in the RAS wild-type subgroup. These observations underpin the recent guidelines for universal germline testing and somatic profiling in pancreatic ductal adenocarcinoma.

Characterization and Clinical Outcomes of DNA Mismatch Repair-deficient Small Bowel Adenocarcinoma.

PURPOSE: The prevalence and clinical characteristics of small bowel adenocarcinomas (SBA) in the setting of Lynch syndrome have not been well studied. We characterized SBA according to DNA mismatch repair and/or microsatellite instability (MMR/MSI) and germline mutation status and compared clinical outcomes. EXPERIMENTAL DESIGN: A single-institution review identified 100 SBAs. Tumors were evaluated for MSI via MSIsensor and/or corresponding MMR protein expression via IHC staining. Germline DNA was analyzed for mutations in known cancer predisposition genes, including MMR (MLH1, MSH2, MSH6, PMS2, and EPCAM). Clinical variables were correlated with MMR/MSI status. RESULTS: Twenty-six percent (26/100; 95% confidence interval, 18.4-35.4) of SBAs exhibited MMR deficiency (MMR-D). Lynch syndrome prevalence was 10% overall and 38.5% among MMR-D SBAs. Median age at SBA diagnosis was similar in non-Lynch syndrome MMR-D versus MMR-proficient (MMR-P) SBAs (65 vs. 61; P = 0.75), but significantly younger in Lynch syndrome (47.5 vs. 61; P = 0.03). The prevalence of synchronous/metachronous cancers was 9% (6/67) in MMR-P versus 34.6% (9/26) in MMR-D SBA, with 66.7% (6/9) of these in Lynch syndrome (P = 0.0002). In the MMR-P group, 52.2% (35/67) of patients presented with metastatic disease, compared with 23.1% (6/26) in the MMR-D group (P = 0.008). In MMR-P stage I/II patients, 88.2% (15/17) recurred, compared with 18.2% (2/11) in the MMR-D group (P = 0.0002). CONCLUSIONS: When compared with MMR-P SBA, MMR-D SBA was associated with earlier stage disease and lower recurrence rates, similar to observations in colorectal cancer. With a 38.5% prevalence in MMR-D SBA, germline Lynch syndrome testing in MMR-D SBA is warranted.

Induction and characterization of pancreatic cancer in a transgenic pig model.

BACKGROUND: Preclinical testing of new locoregional therapies for pancreatic cancer has been challenging, due to the lack of a suitable large animal model. PURPOSE: To develop and characterize a porcine model of pancreatic cancer. Unlike small animals, pigs have similar physiology, drug dosing, and immune response to humans. Locoregional therapy in pigs can be performed using the same size catheters and devices as in humans. METHODS: The Oncopig is a transgenic pig with Cre-inducible TP53R167H and KRASG12D mutations. In 12 Oncopigs, CT-guided core biopsy of the pancreas was performed. The core biopsy was incubated with an adenoviral vector carrying the Cre recombinase gene. The transformed core biopsy was injected back into the pancreas (head, tail, or both). The resulting tumors (n = 19) were characterized on multi-phase contrast-enhanced CT, and on pathology, including immunohistochemistry. Angiographic characterization of the tumors was performed in 3 pigs. RESULTS: Pancreatic tumors developed at 19 out of 22 sites (86%) that were inoculated. Average tumor size was 3.0 cm at 1 week (range: 0.5-5.1 cm). H&E and immunohistochemical stains revealed undifferentiated carcinomas, similar to those of the pancreatobiliary system in humans. Neoplastic cells were accompanied by a major inflammatory component. 1 of 12 pigs only had inflammatory nodules without evidence of neoplasia. On multiphase CT, tumors were hypovascular compared to the normal pancreas. There was no pancreatic duct dilation. In 3 pigs, angiography was performed, and in all 3 cases, the artery supplying the pancreatic tumor could be catheterized using a 2.4 F microcatheter. Selective angiography showed the pancreatic tumor, without extra-pancreatic perfusion. CONCLUSION: Pancreatic cancer can be induced in a transgenic pig. Intra-arterial procedures using catheters designed for human interventions were technically feasible in this large animal model.

Alterations in driver genes are predictive of survival in patients with resected pancreatic ductal adenocarcinoma.

BACKGROUND: KRAS, TP53, CDKN2A, and SMAD4 are established driver genes in pancreatic ductal adenocarcinoma (PDAC). This study was aimed at determining whether the mutational status of driver genes and those involved in DNA repair pathways are associated with clinical outcomes for individuals who undergo resection. METHODS: Eligible individuals were those who underwent resection of PDAC and consented to targeted sequencing of their primary tumor via Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT). Genomic alterations were determined on the basis of MSK-IMPACT results from formalin-fixed, paraffin-embedded samples. Associations between genomic alterations and clinical outcomes were assessed. RESULTS: Targeted sequencing was performed on 283 primary tumors resected between 2004 and 2017. The median follow-up was 23 months among survivors. Alterations in KRAS and TP53 were associated with worse overall survival (OS) in comparison to wild type (median for KRAS, 38.8 months [95% CI, 33.0-45.5 months] vs 91.0 months [95% CI, 34.8 months to not available (NA)]; P = .043; median for TP53, 37.4 months [95% CI, 32.1-42.8 months] vs 65.0 months [95% CI, 33.0 months to NA]; P = .035). KRAS G12D mutations were associated with worse OS (median, 31.6 months [95% CI, 25.3-45.5 months] vs 39.2 months [95% CI, 37.4-75.2 months]; P = .012). TP53 truncating mutations (median, 39.6 months [95% CI, 32.4-75.2 months] vs 33.9 months [95% CI, 24.0-39.0 months]; P = .020) and those associated with loss of heterozygosity (median, 26.6 months [95% CI, 21.6-44.2 months] vs 39.2 months [95% CI, 34.5-49.1 months]; P = .048) had decreased OS. TP53 alterations were independently associated with OS in a multivariate analysis (hazard ratio, 1.54; 95% CI, 1.01-2.33; P = .042). Individuals with germline alterations in homologous recombination deficiency (HRD) genes had improved OS in comparison with those without them (median, not reached vs 37.0 months; 95% CI, 33.0-49.8 months; P = .035). CONCLUSIONS: In patients with resected PDAC, genomic alterations in KRAS and TP53 are associated with worse outcomes, whereas alterations in HRD genes are associated with a favorable prognosis. Further studies are needed to better define these alterations as biomarkers in resected PDAC.

Genomic Methods Identify Homologous Recombination Deficiency in Pancreas Adenocarcinoma and Optimize Treatment Selection.

PURPOSE: Genomic methods can identify homologous recombination deficiency (HRD). Rigorous evaluation of their outcome association to DNA damage response-targeted therapies like platinum in pancreatic ductal adenocarcinoma (PDAC) is essential in maximizing therapeutic outcome. EXPERIMENTAL DESIGN: We evaluated progression-free survival (PFS) and overall survival (OS) of patients with advanced-stage PDAC, who had both germline- and somatic-targeted gene sequencing. Homologous recombination gene mutations (HRm) were evaluated: BRCA1, BRCA2, PALB2, ATM, BAP1, BARD1, BLM, BRIP1, CHEK2, FAM175A, FANCA, FANCC, NBN, RAD50, RAD51, RAD51C, and RTEL1 HRm status was grouped as: (i) germline versus somatic; (ii) core (BRCAs and PALB2) versus non-core (other HRm); and (iii) monoallelic versus biallelic. Genomic instability was compared using large-scale state transition, signature 3, and tumor mutation burden. RESULTS: Among 262 patients, 50 (19%) had HRD (15% germline and 4% somatic). Both groups were analyzed together due to lack of difference in their genomic instability and outcome. Median [95% confidence interval (CI)] follow-up was 21.9 (1.4-57.0) months. Median OS and PFS were 15.5 (14.6-19) and 7 (6.1-8.1) months, respectively. Patients with HRD had improved PFS compared with no HRD when treated with first-line (1L) platinum [HR, 0.44 (95% CI: 0.29-0.67); P < 0.01], but not with 1L-non-platinum. Multivariate analysis showed HRD patients had improved OS regardless of their first-line treatment, but most had platinum exposure during their course. Biallelic HRm (11%) and core HRm (12%) had higher genomic instability, which translated to improved PFS on first-line platinum (1L-platinum) versus 1L-non-platinum. CONCLUSIONS: Pathogenic HRm identifies HRD in patients with PDAC with the best outcome when treated with 1L-platinum. Biallelic HRm and core HRm further enriched benefit from 1L-platinum from HRD.

First-line pembrolizumab and trastuzumab in HER2-positive oesophageal, gastric, or gastro-oesophageal junction cancer: an open-label, single-arm, phase 2 trial.

BACKGROUND: Addition of trastuzumab to first-line chemotherapy improves overall survival in patients with HER2-positive metastatic gastric cancer. We assessed the safety and activity of pembrolizumab in combination with trastuzumab and chemotherapy in first-line HER2-positive metastatic oesophagogastric (gastric, oesophageal, or gastroesophageal junction) cancer. METHODS: This study was an investigator-initiated, open-label, non-randomised, single-arm, single centre, phase 2 trial in patients aged 18 years or older with HER2-positive metastatic oesophagogastric cancer. Eligible patients had measurable or evaluable non-measurable disease, Eastern Cooperative Oncology Group performance status of 0, 1, or 2, and left ventricular ejection fraction of at least 53%. Patients were eligible to receive an initial induction cycle of 200 mg flat dose of intravenous pembrolizumab and 8 mg/kg loading dose of intravenous trastuzumab. For subsequent cycles, patients received 130 mg/m2 of intravenous oxaliplatin or 80 mg/m2 of cisplatin on day 1, 850 mg/m2 of oral capecitabine twice a day for 2 weeks followed by 1 week off (or intravenous 5-fluorouracil, 800 mg/m2 per day on days 1-5), and a 200 mg flat dose of intravenous pembrolizumab, and 6 mg/kg of trastuzumab, administered on day 1 of each 3-week cycle. The primary endpoint was 6-month progression-free survival, defined as the proportion of patients alive and free of progression at 6 months, assessed in patients who received at least one dose of trastuzumab and pembrolizumab. The regimen would be considered worthy of further investigation if 26 or more of 37 patients were progression-free at 6 months. This trial is registered with ClinicalTrials.gov, NCT02954536, and is ongoing, but closed to enrolment. FINDINGS: Between Nov 11, 2016, and Jan 23, 2019, 37 patients were enrolled. At the time of data cutoff on Aug 6, 2019, median follow-up among survivors was 13·0 months (IQR 11·7-23·5). The primary endpoint was achieved; 26 (70%; 95% CI 54-83) of 37 patients were progression-free at 6 months. The most common treatment-related adverse event of any grade was neuropathy, which was reported in 36 (97%) of 37 patients. The most common grade 3 or 4 adverse events were lymphocytopenia (seven [19%] patients with grade 3 and two [5%] with grade 4), grade 3 decreased electrolytes (six [16%] patients), and grade 3 anaemia (four [11%] patients). Serious adverse events occurred in two patients patients (both grade 3 nephritis leading to treatment discontinuation). Four patients discontinued pembrolizumab because of immune-related adverse events. There were no treatment-related deaths. INTERPRETATION: Pembrolizumab can be safely combined with trastuzumab and chemotherapy and has promising activity in HER2-positive metastatic oesophagogastric cancer. A randomised phase 3 clinical trial assessing the efficacy and safety of pembrolizumab versus placebo in combination with trastuzumab and chemotherapy in first-line HER2-positive metastatic oesophagogastric cancer is underway. FUNDING: Merck & Co.

Randomized, Multicenter, Phase II Trial of Gemcitabine and Cisplatin With or Without Veliparib in Patients With Pancreas Adenocarcinoma and a Germline BRCA/PALB2 Mutation.

PURPOSE: Five percent to 9% of pancreatic ductal adenocarcinomas (PDACs) develop in patients with a germline BRCA1/2 or PALB2 (gBRCA/PALB2+) mutation. Phase IB data from a trial that used cisplatin, gemcitabine, and veliparib treatment demonstrated a high response rate (RR), disease control rate (DCR), and overall survival (OS) in this population. We designed an open-label, randomized, multicenter, two-arm phase II trial to investigate cisplatin and gemcitabine with or without veliparib in gBRCA/PALB2+ PDAC. PATIENTS AND METHODS: Eligible patients had untreated gBRCA/PALB2+ PDAC with measurable stage III to IV disease and Eastern Cooperative Oncology Group performance status of 0 to 1. Treatment for patients in arm A consisted of cisplatin 25 mg/m2 and gemcitabine 600 mg/m2 intravenously on days 3 and 10; treatment for patients in arm B was the same as that for patients in arm A, and arm A also received veliparib 80 mg orally twice per day on days 1 to 12 cycled every 3 weeks. The primary end point was RRs of arm A and arm B evaluated separately using a Simon two-stage design. Secondary end points were progression-free survival, DCR, OS, safety, and correlative analyses. RESULTS: Fifty patients were evaluated by modified intention-to-treat analysis. The RR for arm A was 74.1% and 65.2% for arm B (P = .55); both arms exceeded the prespecified activity threshold. DCR was 100% for arm A and 78.3% for arm B (P = .02). Median progression-free survival was 10.1 months for arm A (95% CI, 6.7 to 11.5 months) and 9.7 months for arm B (95% CI, 4.2 to 13.6 months; P = .73). Median OS for arm A was 15.5 months (95% CI, 12.2 to 24.3 months) and 16.4 months for arm B (95% CI, 11.7 to 23.4 months; P = .6). Two-year OS rate for the entire cohort was 30.6% (95% CI, 17.8% to 44.4%), and 3-year OS rate was 17.8% (95% CI, 8.1% to 30.7%). Grade 3 to 4 hematologic toxicities for arm A versus arm B were 13 (48%) versus seven (30%) for neutropenia, 15 (55%) versus two (9%) for thrombocytopenia, and 14 (52%) versus eight (35%) for anemia. CONCLUSION: Cisplatin and gemcitabine is an effective regimen in advanced gBRCA/PALB2+ PDAC. Concurrent veliparib did not improve RR. These data establish cisplatin and gemcitabine as a standard approach in gBRCA/PALB2+ PDAC.

Regorafenib in Combination with First-Line Chemotherapy for Metastatic Esophagogastric Cancer.

BACKGROUND: Angiogenesis is critical to gastroesophageal adenocarcinoma growth and metastasis. Regorafenib is a multikinase inhibitor targeting angiogenic and stromal receptor tyrosine kinases. We evaluated whether regorafenib augments the antitumor effect of first-line chemotherapy in metastatic esophagogastric cancer. MATERIALS AND METHODS: Patients with previously untreated metastatic gastroesophageal adenocarcinoma received 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) every 14 days and regorafenib 160 mg daily on days 4 to 10 of each 14-day cycle. The primary endpoint was 6-month progression-free survival (PFS). To identify predictive biomarkers of outcome, we examined correlations between genomic characteristics of sequenced pretreatment tumors and PFS. RESULTS: Between August 2013 and November 2014, 36 patients with metastatic esophagogastric cancer were accrued to this single-center phase II study (NCT01913639). The most common grade 3-4 treatment-related adverse events were neutropenia (36%), leucopenia (11%) and hypertension (8%). The 6-month PFS was 53% (95% confidence interval [CI], 38%-71%), the objective response rate was 54% (95% CI, 37%-70%), and the disease control rate was 77% (95% CI, 67%-94%). Next-generation sequencing did not identify any genomic alterations significantly correlated with response, and there was no association between homologous recombination deficiency and PFS with platinum-based chemotherapy. CONCLUSION: Regorafenib (one week on-one week off schedule) is well tolerated in combination with first-line FOLFOX but does not improve 6-month PFS relative to historical control. IMPLICATIONS FOR PRACTICE: Prognosis for metastatic esophagogastric cancer remains poor despite modern systemic therapy regimens. This phase II trial indicates that the combination of regorafenib and FOLFOX is well tolerated but does not add to the efficacy of first-line chemotherapy in metastatic esophagogastric cancer. Notably, recently reported data suggest potential synergy between regorafenib and the PD-1 inhibitor nivolumab. As this study demonstrates that regorafenib plus FOLFOX is safe, and combined chemotherapy and immunotherapy show favorable toxicity profiles, future studies combining immunotherapy with regorafenib and chemotherapy may be feasible.

Clinical and Molecular Predictors of Response to Immune Checkpoint Inhibitors in Patients with Advanced Esophagogastric Cancer.

PURPOSE: Immune checkpoint inhibitors (ICI) are effective in only a minority of patients with esophagogastric cancer (EGC). Here, we aimed to identify predictors of durable clinical benefit to ICI in EGC. EXPERIMENTAL DESIGN: Patients with advanced EGC treated with ICIs at Memorial Sloan Kettering Cancer Center (New York, NY) were identified. Clinicopathologic variables were assessed. In patients profiled by MSK-IMPACT-targeted sequencing, outcomes were correlated with tumor genomic features. RESULTS: One-hundred sixty-one patients were treated with ICIs (110 with anti-PD-1/PD-L1 antibodies and 51 with anti-CTLA-4 and PD-1/PD-L1 antibodies). The median progression-free survival (PFS) and overall survival (OS) were 1.7 and 4.9 months, respectively. Greater number of disease sites (≥3), liver metastases, treatment with ≥3 prior therapies and ECOG performance status ≥2 were associated with poorer PFS and OS. Patients treated with combination ICI and those with PD-L1-positive tumors had improved outcomes. There was no difference in outcomes between patients treated with antibiotics during or in the 2 months preceding ICI treatment versus those who were not. Occurrence of irAEs was associated with improved OS. In genomically profiled tumors (n = 89), survival was associated with increasing tumor mutation burden (TMB). However, in multivariable analyses and when microsatellite unstable (MSI) patients were excluded, a significant association was no longer observed. CONCLUSIONS: In patients with advanced EGC, heavily pretreated patients, those with high-volume disease and/or poor PS were less likely to benefit from ICI. irAEs were associated with improved OS. TMB correlated with improved survival, but this association was not observed when MSI-high patients were excluded.