Distinct genomic landscapes of gastroesophageal adenocarcinoma depending on PD-L1 expression identify mutations in RAS-MAPK pathway and TP53 as potential predictors of immunotherapy efficacy.

BACKGROUND: The impact of molecular alterations on programmed death-ligand 1 (PD-L1) combined positive score (CPS) is not well studied in gastroesophageal adenocarcinomas (GEAs). We aimed to characterize genomic features of tumors with different CPSs in GEAs. PATIENTS AND METHODS: Genomic alterations of 2518 GEAs were compared in three groups (PD-L1 CPS ≥ 10, high; CPS = 1-9, intermediate; CPS < 1, low) using next-generation sequencing. We assessed the impact of gene mutations on the efficacy of immune checkpoint inhibitors (ICIs) and tumor immune environment based on the Memorial Sloan Kettering Cancer Center and The Cancer Genome Atlas databases. RESULTS: High, intermediate, and low CPSs were seen in 18%, 54% and 28% of GEAs, respectively. PD-L1 positivity was less prevalent in women and in tissues derived from metastatic sites. PD-L1 CPS was positively associated with mismatch repair deficiency/microsatellite instability-high, but independent of tumor mutation burden distribution. Tumors with mutations in KRAS, TP53, and RAS-mitogen-activated protein kinase (MAPK) pathway were associated with higher PD-L1 CPSs in the mismatch repair proficiency and microsatellite stability (pMMR&MSS) subgroup. Patients with RAS-MAPK pathway alterations had longer overall survival (OS) from ICIs compared to wildtype (WT) patients [27 versus 13 months, hazard ratio (HR) = 0.36, 95% confidence interval (CI): 0.19-0.7, P = 0.016] and a similar trend was observed in the MSS subgroup (P = 0.11). In contrast, patients with TP53 mutations had worse OS from ICIs compared to TP53-WT patients in the MSS subgroup (5 versus 21 months, HR = 2.39, 95% CI: 1.24-4.61, P = 0.016). CONCLUSIONS: This is the largest study to investigate the distinct genomic landscapes of GEAs with different PD-L1 CPSs. Our data may provide novel insights for patient selection using mutations in TP53 and RAS-MAPK pathway and for the development of rational combination immunotherapies in GEAs.

Gefitinib in definitive management of esophageal or gastroesophageal junction cancer: a retrospective analysis of two clinical trials.

The role of epidermal growth factor receptor inhibition in resectable esophageal/gastroesophageal junction (E/GEJ) cancer is uncertain. Results from two Cleveland Clinic trials of concurrent chemoradiotherapy (CCRT) and surgery are updated and retrospectively compared, the second study differing only by the addition of gefitinib (G) to the treatment regimen. Eligibility required a diagnosis of E/GEJ squamous cell or adenocarcinoma, with an endoscopic ultrasound stage of at least T3, N1, or M1a (American Joint Committee on Cancer 6th). Patients in both trials received 5-fluorouracil (1000 mg/m(2) /day) and cisplatin (20 mg/m(2) /day) as continuous infusions over days 1-4 along with 30 Gy radiation at 1.5 Gy bid. Surgery followed in 4-6 weeks; identical CCRT was given 6-10 weeks later. The second trial added G, 250 mg/day, on day 1 for 4 weeks, and again with postoperative CCRT for 2 years. Preliminary results and comparisons have been previously published. Clinical characteristics were similar between the 80 patients on the G trial (2003-2006) and the 93 patients on the no-G trial (1999-2003). Minimum follow-up for all patients was 5 years. Multivariable analyses comparing the G versus no-G patients and adjusting for statistically significant covariates demonstrated improved overall survival (hazard ratio [HR] 0.64, 95% confidence interval [CI] = 0.45-0.91, P = 0.012), recurrence-free survival (HR 0.61, 95% CI = 0.43-0.86, P = 0.006), and distant recurrence (HR 0.68, 95% CI = 0.45-1.00, P = 0.05), but not locoregional recurrence. Although this retrospective comparison can only be considered exploratory, it suggests that G may improve clinical outcomes when combined with CCRT and surgery in the definitive treatment of E/GEJ cancer.

A phase II trial of gemcitabine, irinotecan and panitumumab in advanced cholangiocarcinoma.

BACKGROUND: Current data suggest that chemotherapy combinations may be superior to single agents in biliary tract cancer. The epidermal growth factor receptor (EGFR) pathway appears to be associated with tumor stage, prognosis and response to therapy. This trial was designed to evaluate the tolerability and efficacy of the combination of panitumumab, a monoclonal anti-EGFR antibody, with gemcitabine and irinotecan. PATIENTS AND METHODS: Patients with advanced (unresectable or metastatic) cholangiocarcinoma, ECOG PS 0-2, and adequate organ function were treated with panitumumab (9 mg/kg) on day 1, and gemcitabine (1000 mg/m(2)) and irinotecan (100 mg/m(2)) on days 1 and 8 of a 21-day cycle. The primary objective was to evaluate the 5-month progression-free survival (PFS). Secondary objectives included overall response rate (ORR) and overall survival (OS). Mutational analyses of EGFR, KRAS and BRAF were carried out when feasible. RESULTS: Thirty-five patients received a median of 7 (0-30) cycles. The most common grade 3/4 toxic effects were neutropenia (10 patients, 29%), thrombocytopenia (10 patients, 29%), skin rash (13 patients, 37%) and dehydration (9 patients, 26%). Two patients had CR, 9 had partial response (PR), and 15 had SD for a disease-control rate of 74% (by RECIST) in 28 assessable patients. Two patients went on to have surgical resection. The 5-month PFS was 69%. The median PFS was 9.7 months and the median OS was 12.9 months. In 17 testable samples, no EGFR or BRAF mutations were identified; there were 7 KRAS mutations, with no difference in OS by KRAS status. CONCLUSIONS: This study showed encouraging efficacy of this regimen with good tolerability. Further study in this area is warranted. Clinical Trials Number: The trial was registered with the National Cancer Institute (www.clinicaltrials.gov identifier NCT00948935).