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.

Next-generation sequencing (NGS) of cell-free circulating tumor DNA and tumor tissue in patients with advanced urothelial cancer: a pilot assessment of concordance.

BACKGROUND: Advances in cancer genome sequencing have led to the development of various next-generation sequencing (NGS) platforms. There is paucity of data regarding concordance of different NGS tests carried out in the same patient. METHODS: Here, we report a pilot analysis of 22 patients with metastatic urinary tract cancer and available NGS data from paired tumor tissue [FoundationOne (F1)] and cell-free circulating tumor DNA (ctDNA) [Guardant360 (G360)]. RESULTS: The median time between the diagnosis of stage IV disease and the first genomic test was 23.5 days (0-767), after a median number of 0 (0-3) prior systemic lines of treatment of advanced disease. Most frequent genomic alterations (GA) were found in the genes TP53 (50.0%), TERT promoter (36.3%); ARID1 (29.5%); FGFR2/3 (20.5%), PIK3CA (20.5%) and ERBB2 (18.2%). While we identified GA in both tests, the overall concordance between the two platforms was only 16.4% (0%-50%), and 17.1% (0%-50%) for those patients (n = 6) with both tests conducted around the same time (median difference = 36 days). On the contrary, in the subgroup of patients (n = 5) with repeated NGS in ctDNA after a median of 1 systemic therapy between the two tests, average concordance was 55.5% (12.1%-100.0%). Tumor tissue mutational burden was significantly associated with number of GA in G360 report (P < 0.001), number of known GA (P = 0.009) and number of variants of unknown significance (VUS) in F1 report (P < 0.001), and with total number of GA (non-VUS and VUS) in F1 report (P < 0.001). CONCLUSIONS: This study suggests a significant discordance between clinically available NGS panels in advanced urothelial cancer, even when collected around the same time. There is a need for better understanding of these two possibly complementary NGS platforms for better integration into clinical practice.

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.

Phase I study of peposertib and avelumab with or without palliative radiotherapy in patients with advanced solid tumors.

INTRODUCTION: We report results from a phase I, three-part, dose-escalation study of peposertib, a DNA-dependent protein kinase inhibitor, in combination with avelumab, an immune checkpoint inhibitor, with or without radiotherapy in patients with advanced solid tumors. MATERIALS AND METHODS: Peposertib 100-400 mg twice daily (b.i.d.) or 100-250 mg once daily (q.d.) was administered in combination with avelumab 800 mg every 2 weeks in Part A or avelumab plus radiotherapy (3 Gy/fraction × 10 days) in Part B. Part FE assessed the effect of food on the pharmacokinetics of peposertib plus avelumab. The primary endpoint in Parts A and B was dose-limiting toxicity (DLT). Secondary endpoints were safety, best overall response per RECIST version 1.1, and pharmacokinetics. The recommended phase II dose (RP2D) and maximum tolerated dose (MTD) were determined in Parts A and B. RESULTS: In Part A, peposertib doses administered were 100 mg (n = 4), 200 mg (n = 11), 250 mg (n = 4), 300 mg (n = 6), and 400 mg (n = 4) b.i.d. Of DLT-evaluable patients, one each had DLT at the 250-mg and 300-mg dose levels and three had DLT at the 400-mg b.i.d. dose level. In Part B, peposertib doses administered were 100 mg (n = 3), 150 mg (n = 3), 200 mg (n = 4), and 250 mg (n = 9) q.d.; no DLT was reported in evaluable patients. Peposertib 200 mg b.i.d. plus avelumab and peposertib 250 mg q.d. plus avelumab and radiotherapy were declared as the RP2D/MTD. No objective responses were observed in Part A or B; one patient had a partial response in Part FE. Peposertib exposure was generally dose proportional. CONCLUSIONS: Peposertib doses up to 200 mg b.i.d. in combination with avelumab and up to 250 mg q.d. in combination with avelumab and radiotherapy were tolerable in patients with advanced solid tumors; however, antitumor activity was limited. GOV IDENTIFIER: NCT03724890.

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).

Temporally regulated and tissue-specific gene manipulations in the adult and embryonic heart using a tamoxifen-inducible Cre protein.

The advent of conditional and tissue-specific recombination systems in gene-targeted or transgenic mice has permitted an assessment of single gene function in a temporally regulated and cell-specific manner. Here we generated transgenic mice expressing a tamoxifen-inducible Cre recombinase protein fused to two mutant estrogen-receptor ligand-binding domains (MerCreMer) under the control of the alpha-myosin heavy chain promoter. These transgenic mice were crossed with the ROSA26 lacZ-flox-targeted mice to examine Cre recombinase activity and the fidelity of the system. The data demonstrate essentially no Cre-mediated recombination in the embryonic, neonatal, or adult heart in the absence of inducing agent but >80% recombination after only four tamoxifen injections. Expression of the MerCreMer fusion protein within the adult heart did not affect cardiac performance, cellular architecture, or expression of hypertrophic marker genes, demonstrating that the transgene-encoded protein is relatively innocuous. In summary, MerCreMer transgenic mice represent a tool for temporally regulated inactivation of any loxP-targeted gene within the developing and adult heart or for specifically directing recombination and expression of a loxP-inactivated cardiac transgene in the heart.

Significance of a prenatally diagnosed del(10)(q23).

Structural chromosome mosaicism is rare. We report a case of prenatal mosaicism for a deletion of chromosome 10(q23). To our knowledge, there are only three reports of prenatally diagnosed cases of del(10)(q23). Two of these cases were due to an inherited fragile site. In the present case amniocentesis revealed 46,XY,del(10)(q23)[9]/46,XY[45]. Follow-up chromosome analysis of peripheral blood and placental tissue from a phenotypically normal liveborn male revealed the del(10)(q23) in only 3/100 blood cells grown in low-folate medium. It appears that prenatally diagnosed deleted (10q) mosaicism represents culture artifact and is not clinically significant.