Initial Report: Personalized Circulating Tumor DNA and Survival in Patients with Resectable Pancreatic Cancer.

ABSTRACT: BACKGROUND: Pancreatic adenocarcinoma (PDAC) is highly lethal with up to 80% of resected patients experiencing disease recurrence within 2 years (Watanabe, Nakamura, Kimura et al in Int J Mol Sci 23(19):11521, 2022). Cross-sectional imaging and serum tumor markers are used for monitoring post-operative recurrence; however, both have significant limitations (Edland, Tjensvoll, Oltedal et al in Mol Oncol 17:1857-1870, 2023). Circulating tumor DNA (ctDNA) has emerged as a valuable prognostic tool to measure molecular residual disease (MRD) and predict recurrence in solid tumors (Watanabe, Nakamura, Kimura et al in Int J Mol Sci 23(19):11521, 2022). In this study, we evaluated the feasibility of a personalized, tumor-informed ctDNA assay to detect recurrence prior to standard surveillance tools in patients with PDAC. PATIENTS AND METHODS: After Institutional Review Board (IRB) approval (Pro00106870), we assessed serial ctDNA measurements (n = 177) from 35 patients with resectable PDAC treated by either upfront resection or neoadjuvant chemotherapy. Plasma samples (median 4 ml, interquartile range 0.6-5.9 ml) were isolated from blood collected in EDTA tubes and banked at diagnosis, during neoadjuvant therapy if applicable, on the day of surgery, and every 2-3 months postoperatively. A tumor-informed assay (Signatera™, Natera, Inc.) that tracks up to 16 individual-specific, somatic single nucleotide variants in the corresponding patient's plasma samples were used for ctDNA detection. Survival was calculated using Kaplan-Meier curves, and significance was determined with the log-rank test. RESULTS: Personalized ctDNA assays were successfully designed for all patients (with 32/35 patients having 16-plex assays). Median follow-up from initial treatment was 13 months (range 1-26 months; Table 1). ctDNA-positivity at any time point was observed in 40% (14/35) of patients. During the follow-up period, 18 patients (51%) developed radiographic evidence of recurrence after a median of 9 months of follow-up (range 1-26 months). At the time of radiographic recurrence, 50% (9/18) of patients were ctDNA-positive. During the immediate postoperative period (up to 9 weeks post-surgery), RFS and OS were significantly inferior in patients who were ctDNA-positive versus ctDNA-negative (RFS 97 versus 297 days, p < 0.001; OS 110 versus 381 days, p < 0.001; Fig. 1). Table 1 Cohort demographics (N = 35); patient demographics, tumor characteristics, and survival Gender (%) Female 17 (49%) Male 18 (51%) Median age (IQR) 70 years (65-75 years) Neoadjuvant treatment (%) 11 (31%) Median sample plasma volume (IQR) 4.0 mL (0.6-5.9 mL) Median follow-up (range) 13 months (1-26 months) Median initial CA 19-9 in U/mL (IQR) 56 (18-160) Median tumor size in cm (IQR) 2.5 (1.8-3.3) Median number of positive lymph nodes (IQR) 1 (0-3) Median recurrence-free survival 9.4 months Median overall survival N/A (not reached) Fig. 1 a Overview plot showing longitudinal ctDNA status, treatment regimen, and clinical outcomes for each patient (N = 35); median follow-up from the start of the neoadjuvant therapy/surgery was 13 months (range 1-26 months); ctDNA at any time point was 40% (14/35); out of the 35 patients, 18 (51%) developed radiographic evidence of recurrence (median RFS: 9 months), and of these 18 patients with clinical recurrence, 9 (50%) were ctDNA-positive and the remaining ctDNA-negative; notably, all ctDNA-negative patients with recurrence had suboptimal plasma volume available for ctDNA analysis; b, c Kaplan-Meier estimates representing the association of ctDNA status with (b) RFS and (c) OS, at MRD time point (9 weeks post-surgery) DISCUSSION: Our study demonstrates the feasibility of tumor-informed ctDNA-based MRD testing in resectable PDAC and shows that MRD detected by ctDNA within the immediate postoperative period portends a dismal prognosis. This information is valuable for both patients and clinicians in setting prognostic expectations.

Transorganogenesis and transdifferentiation in C. elegans are dependent on differentiated cell identity.

The differentiated cell identities and structure of fully formed organs are generally stable after their development. In contrast, we report here that development of the C. elegans proximal somatic gonad (hermaphrodite uterus and spermathecae, and male vas deferens) can be redirected into intestine-like organs by brief expression of the ELT-7 GATA transcription factor. This process converts one developing organ into another and can hence be considered "transorganogenesis." We show that, following pulsed ELT-7 expression, cells of the uterus activate and maintain intestine-specific gene expression and are transformed at the ultrastructural level to form an epithelial tube resembling the normal intestine formed during embryogenesis. Ubiquitous ELT-7 expression activates intestinal markers in many different cell types but only cells in the somatic gonad and pharynx appear to become fully reprogrammed. We found that ectopic expression of other endoderm-promoting transcription factors, but not muscle- or ectoderm- promoting transcription factors, redirects the fate of these organs, suggesting that pharyngeal and somatic gonad cells are specifically competent to adopt intestine identity. Although the intestine, pharynx, and somatic gonad are derived from distant cell lineages, they all express the PHA-4/FoxA transcription factor. While we found that post-embryonic PHA-4 is not necessary for pharynx or uterus reprogramming and PHA-4 is not sufficient in combination with ELT-7 to induce reprogramming in other cells types, knock down of PHA-4 during embryogenesis, which abolishes normal pharynx differentiation, prevents pharyngeal precursors from being reprogrammed into intestine. These results suggest that differentiated cell identity determines susceptibility to transdifferentiation and highlight the importance of cellular context in controlling competency for reprogramming.

Neoadjuvant atezolizumab plus chemotherapy in gastric and gastroesophageal junction adenocarcinoma: the phase 2 PANDA trial.

Gastric and gastroesophageal junction (G/GEJ) cancers carry a poor prognosis, and despite recent advancements, most patients die of their disease. Although immune checkpoint blockade became part of the standard-of-care for patients with metastatic G/GEJ cancers, its efficacy and impact on the tumor microenvironment (TME) in early disease remain largely unknown. We hypothesized higher efficacy of neoadjuvant immunotherapy plus chemotherapy in patients with nonmetastatic G/GEJ cancer. In the phase 2 PANDA trial, patients with previously untreated resectable G/GEJ tumors (n = 21) received neoadjuvant treatment with one cycle of atezolizumab monotherapy followed by four cycles of atezolizumab plus docetaxel, oxaliplatin and capecitabine. Treatment was well tolerated. There were grade 3 immune-related adverse events in two of 20 patients (10%) but no grade 4 or 5 immune-related adverse events, and all patients underwent resection without treatment-related delays, meeting the primary endpoint of safety and feasibility. Tissue was obtained at multiple time points, allowing analysis of the effects of single-agent anti-programmed cell death ligand 1 (PD-L1) and the subsequent combination with chemotherapy on the TME. Twenty of 21 patients underwent surgery and were evaluable for secondary pathologic response and survival endpoints, and 19 were evaluable for exploratory translational analyses. A major pathologic response (≤10% residual viable tumor) was observed in 14 of 20 (70%, 95% confidence interval 46-88%) patients, including 9 (45%, 95% confidence interval 23-68%) pathologic complete responses. At a median follow-up of 47 months, 13 of 14 responders were alive and disease-free, and five of six nonresponders had died as a result of recurrence. Notably, baseline anti-programmed cell death protein 1 (PD-1)+CD8+ T cell infiltration was significantly higher in responders versus nonresponders, and comparison of TME alterations following anti-PD-L1 monotherapy versus the subsequent combination with chemotherapy showed an increased immune activation on single-agent PD-1/L1 axis blockade. On the basis of these data, monotherapy anti-PD-L1 before its combination with chemotherapy warrants further exploration and validation in a larger cohort of patients with nonmetastatic G/GEJ cancer. ClinicalTrials.gov registration: NCT03448835 .

Perioperative Modified FOLFIRINOX for Resectable Pancreatic Cancer: A Nonrandomized Controlled Trial.

Importance: Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignant tumor, and durable disease control is rare with the current standard of care, even for patients who undergo surgical resection. Objective: To assess whether neoadjuvant modified 5-fluorouracil, leucovorin, oxaliplatin, and irinotecan (mFOLFIRINOX) leads to early control of micrometastasis and improves survival. Design, Setting, and Participants: This open-label, single-arm, phase 2 nonrandomized controlled trial for resectable PDAC was conducted at the Yale Smilow Cancer Hospital from April 3, 2014, to August 16, 2021. Pancreatic protocol computed tomography was performed at diagnosis to assess surgical candidacy. Data were analyzed from January to July 2023. Interventions: Patients received 6 cycles of neoadjuvant mFOLFIRINOX before surgery and 6 cycles of adjuvant mFOLFIRINOX. Whole blood was collected and processed to stored plasma for analysis of circulating tumor DNA (ctDNA) levels. Tumors were evaluated for treatment response and keratin 17 (K17) expression. Main Outcomes and Measures: The primary end point was 12-month progression-free survival (PFS) rate. Additional end points included overall survival (OS), ctDNA level, tumor molecular features, and K17 tumor levels. Survival curves were summarized using Kaplan-Meier estimator. Results: Of 46 patients who received mFOLFIRINOX, 31 (67%) were male, and the median (range) age was 65 (46-80) years. A total of 37 (80%) completed 6 preoperative cycles and 33 (72%) underwent surgery. A total of 27 patients (59%) underwent resection per protocol (25 with R0 disease and 2 with R1 disease); metastatic or unresectable disease was identified in 6 patients during exploration. Ten patients underwent surgery off protocol. The 12-month PFS was 67% (90% CI, 56.9-100); the median PFS and OS were 16.6 months (95% CI, 13.3-40.6) and 37.2 months (95% CI, 17.5-not reached), respectively. Baseline ctDNA levels were detected in 16 of 22 patients (73%) and in 3 of 17 (18%) after 6 cycles of mFOLFIRINOX. Those with detectable ctDNA levels 4 weeks postresection had worse PFS (hazard ratio [HR], 34.0; 95% CI, 2.6-4758.6; P = .006) and OS (HR, 11.7; 95% CI, 1.5-129.9; P = .02) compared with those with undetectable levels. Patients with high K17 expression had nonsignificantly worse PFS (HR, 2.7; 95% CI, 0.7-10.9; P = .09) and OS (HR, 3.2; 95% CI, 0.8-13.6; P = .07). Conclusions and Relevance: This nonrandomized controlled trial met its primary end point, and perioperative mFOLFIRINOX warrants further evaluation in randomized clinical trials. Postoperative ctDNA positivity was strongly associated with recurrence. K17 and ctDNA are promising biomarkers that require additional validation in future prospective studies. Trial Registration: ClinicalTrials.gov Identifier: NCT02047474.

The multipotency-to-commitment transition in Caenorhabditis elegans-implications for reprogramming from cells to organs.

In animal embryos, cells transition from a multipotential state, with the capacity to adopt multiple fates, into an irreversible, committed state of differentiation. This multipotency-to-commitment transition (MCT) is evident from experiments in which cell fate is reprogrammed by transcription factors for cell type-specific differentiation, as has been observed extensively in Caenorhabditis elegans. Although factors that direct differentiation into each of the three germ layer types cannot generally reprogram cells after the MCT in this animal, transcription factors for endoderm development are able to do so in multiple differentiated cell types. In one case, these factors can redirect the development of an entire organ in the process of "transorganogenesis". Natural transdifferentiation also occurs in a small number of differentiated cells during normal C. elegans development. We review these reprogramming and transdifferentiation events, highlighting the cellular and developmental contexts in which they occur, and discuss common themes underlying direct cell lineage reprogramming. Although certain aspects may be unique to the model system, growing evidence suggests that some mechanisms are evolutionarily conserved and may shed light on cellular plasticity and disease in humans.