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Abstract Background Regorafenib and anti-EGFR monoclonal antibodies are standard therapies for RAS/BRAF wild-type (WT) metastatic colorectal cancer (mCRC) in the refractory setting, but the optimal sequencing remains unknown. Herein, we report results from REVERCE II, a randomized phase II trial evaluating the efficacy and safety of sequencing these therapies. Methods Patients with RAS WT mCRC previously treated with fluoropyrimidine, oxaliplatin, and irinotecan were randomized to receive (R-E) regorafenib followed by anti-EGFR therapy ± irinotecan or (E-R) anti-EGFR therapy ± irinotecan, followed by regorafenib sequentially. The primary endpoint was overall survival (OS). Key secondary endpoints included progression-free survival (PFS) with initial (PFS1) and second treatment (PFS2), sequential treatment PFS (stPFS), objective response rate (ORR), and safety. Exploratory endpoints included serial biomarker analyses. Unfortunately, the trial was closed prematurely due to slow enrollment and lack of funding. Results Twenty-two patients were enrolled (R-E: n = 12; E-R: n = 10) with sequential treatment initiated in 33% (4/12) and 80% (8/10) of patients in R-E and E-R, respectively. Median OS for R-E and E-R was 21.9 and 13.3 months, respectively (one-sided P = .114). PFS1 was 2.5 (R-E) vs 5.6 months (E-R) (one-sided P = .998), while PFS2 was 3.7 vs 2.0 months (one-sided P = .086). stPFS was similar (9.3 vs 9.6 months; one-sided P = .358). ORR for initial treatment was 0% in R-E and 20% (2/8) in E-R. Sequential treatment ORR was 25% (n = 1/4) in R-E and 0% in E-R. No significant differences were observed adverse effects between arms. Conclusion While the study was closed prematurely prior to completion, the sequence of regorafenib before to anti-EGFR therapy suggested a possible survival benefit. Further studies may help better determine the optimal treatment sequencing strategy in refractory mCRC.

ABSTRACT Many real‐world patients with advanced biliary tract cancer (BTC) are excluded by TOPAZ‐1 criteria; this study assessed cisplatin and gemcitabine plus durvalumab (CGD) efficacy and safety in these patients. Data from 1358 patients with advanced BTC treated with first‐line CGD across 55 international centers were retrospectively analyzed. Patients were classified as TOPAZ‐1‐in (meeting all inclusion criteria) or TOPAZ‐1‐out (meeting ≥ 1 exclusion criterion). Primary endpoints were overall survival (OS) and progression‐free survival (PFS); secondary endpoints included objective response rate (ORR), disease control rate (DCR), and safety. Furthermore, OS and PFS of the TOPAZ‐1‐out cohort were compared with reconstructed survival data from the phase III trial. 912 (67.1%) patients were classified as TOPAZ‐1‐in , and 446 (32.9%) as TOPAZ‐1‐out . After a median follow‐up of 14.5 months (95% CI: 13.7–36.5), OS was 16.1 months in TOPAZ‐1‐in and 12.5 months in TOPAZ‐1‐out (HR 0.69, 95% CI: 14.6–16.5, p = 0.0001); PFS was 8.2 versus 6.5 months (HR 0.73, 95% CI: 7.1–8.1, p < 0.0001). Median OS in the TOPAZ‐1‐out cohort (12.5 months) was nearly identical to the phase III trial experimental arm (12.9 months; HR 1.15, p = 0.13); for PFS the HR was 1.12 (95% CI 0.93–1.42; p = 0.09). Among TOPAZ‐1‐out patients, active infection, elevated bilirubin, and ECOG PS > 1 were linked to poorer OS, while no detrimental impact emerged for ALT/AST abnormalities, corticosteroid use, renal or hematologic parameters, or prior surgery within 6 months, suggesting treatment effectiveness was broadly maintained across clinical subgroups. Furthermore, TOPAZ‐1‐out patients experienced no significant increase in adverse events compared with the TOPAZ‐1‐in group. Real‐world data suggest CGD may be effective in TOPAZ‐1‐out patients, with no evident increase in toxicity, supporting the potential expanded use of the regimen in clinical practice.

ABSTRACT Surgery after response to first‐line chemoimmunotherapy may offer a potential curative option for patients with locally advanced biliary tract cancer (BTC) initially considered unresectable. However, robust real‐world evidence in this setting remains limited. We retrospectively analyzed patients with locally advanced BTC treated with first‐line cisplatin, gemcitabine, and durvalumab (CGD) across 55 centers in 12 countries. Endpoints included overall survival (OS), progression‐free survival (PFS), disease‐free survival (DFS) among resected patients, objective response rate (ORR), and the prognostic impact of surgery. A multivariable logistic regression model was developed to predict surgical conversion using baseline clinical and laboratory variables. Among 1358 screened patients, 219 had locally advanced disease and were included in the analysis. Median follow‐up was 14.5 months. ORR was 34.6%, with median PFS and OS of 10.0 and 20.7 months, respectively. Twenty‐four patients (10.9%) underwent surgical resection after systemic therapy. Median OS was 22.5 months in resected patients versus 19.9 months in those who did not undergo surgery. Median DFS after resection was 15.8 months. Pathological lymph node involvement was independently associated with shorter DFS. Larger baseline tumor size correlated with higher odds of radiological response but not with OS. An exploratory elastic‐net model retained four baseline variables and showed moderate discriminative ability for surgical conversion, with an apparent AUC of 0.72 and an optimism‐corrected AUC of 0.65. First‐line CGD enabled secondary resection in approximately 11% of patients with locally advanced BTC. A simple baseline model may support patient selection for conversion surgery, although prospective validation is needed.

Purpose: Neuroendocrine neoplasms (NENs) are increasingly recognized to have a hereditary predilection, yet the prevalence and clinical relevance of pathogenic germline variants (PGVs) in unselected patients with NEN remain poorly defined. This prospective, multicenter study aimed to evaluate the prevalence and clinical utility of PGVs through universal multigene panel testing in a diverse cohort of patients with NENs. Patients and Methods: Between 2018 and 2024, we enrolled unselected patients with NENs from 3 Mayo Clinic Cancer Centers. Germline genetic testing was performed using a next-generation sequencing panel of up to 84 cancer predisposition genes. Patients were not selected based on age, disease stage, ethnicity, or family history. Variants were classified as PGVs, variants of uncertain significance (VUS), or negative. Clinical and demographic data were analyzed descriptively. Results: Among 88 patients, PGVs were identified in 15.9% (n=14), most frequently in high- or moderate-penetrance genes including MEN1 , CHEK2 , MITF , and MUTYH . PGVs were most commonly found in pancreatic NENs [n=12/55 (21.8%)], followed by small bowel NENs [n=2/20 (10%)], with no PGVs detected in lung NENs. Mismatch repair (MMR) gene alterations were identified in 5.7% of patients, including 1 MLH1 PGV and 4 MSH2/MSH6 VUS, 2 of which demonstrated MMR deficiency by protein testing. VUS were reported in 34.1% of patients. Notably, 35.7% of PGV-positive patients did not meet current NCCN or ACMG testing criteria, and 53.9% had PGVs in genes outside of cancer-specific guideline recommendations. Conclusions: Universal germline testing in unselected patients with NEN identified clinically relevant PGVs in over 15% of cases. These findings support broader genetic testing approaches to guide treatment, enhance familial risk assessment, and inform cascade testing—regardless of traditional clinical selection criteria.

3592 Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent dose-limiting toxicity from oxaliplatin that impairs quality of life in gastrointestinal (GI) cancer patients (pts). While strategies to limit exposure exist, their impact on survival remains debated. We evaluated whether reduced oxaliplatin exposure (ROE) maintains survival while mitigating toxicity. Methods: We conducted a systematic review and meta-analysis (PubMed, Embase, Scopus, Web of Science, EBM Reviews) of studies comparing ROE vs standard-duration oxaliplatin-based chemotherapy in GI cancers. ROE was defined as planned limitation of oxaliplatin exposure, including shortened duration (3-4 months), maintenance-based de-escalation, or stop-and-go strategies. Primary endpoints were disease-free survival (DFS) in curative settings, progression-free survival (PFS) in palliative settings, and overall survival (OS). Secondary endpoints included grade ≥3 CIPN and grade ≥3 adverse events (AEs). Random-effects models used Hartung-Knapp-Sidik-Jonkman correction. Heterogeneity was assessed via I² and Cochran’s Q. Results: 24 studies, comprising 15 randomized controlled trials (RCTs) and 9 retrospective cohorts, were included (N = 30,404 pts; ROE: 13,348; control: 17,056). Settings included adjuvant colorectal cancer (CRC; n = 14), metastatic CRC (mCRC; n = 5), gastric cancer (GC) (adjuvant n = 1, metastatic n = 3), and metastatic pancreatic cancer (PDAC) (n = 1). ROE strategies included shortened duration (n = 14), maintenance (n = 8), and stop-and-go (n = 2). In adjuvant CRC, ROE did not compromise DFS (HR 1.07; 95% CI, 0.98-1.16; p = 0.12; I² = 21.7%), including in high-risk subgroups (HR 1.14; 95% CI, 0.93-1.40; p = 0.14; I² = 38.9%); OS was also not different between groups (HR 1.00; 95% CI, 0.94-1.07; p = 0.89; I² = 0%), including high-risk pts (HR 1.01; 95% CI, 0.93-1.10; p = 0.68; I² = 0%). In mCRC, ROE showed no detriment to PFS (HR 1.11; 95% CI, 0.99-1.25; p = 0.07; I² = 0%) or OS (HR 1.06; 95% CI, 0.92-1.23; p = 0.33; I² = 0%). Similarly, in metastatic gastric cancer, PFS (HR 0.82; 95% CI, 0.34-1.99; p = 0.44; I² = 77.3%) and OS (HR 0.90; 95% CI, 0.67-1.21; p = 0.26; I² = 0%) were comparable. Findings remained concordant after restricting the analysis to only RCTs. Pooled analysis was not feasible for PDAC and adjuvant GC studies, but individual study findings were consistent with the above. ROE significantly reduced the risk of grade ≥3 CIPN (OR 0.32; 95% CI, 0.20-0.53; p < 0.001; I² = 80.6%) and overall grade ≥3 AEs (OR 0.65; 95% CI, 0.50-0.86; p = 0.01; I² = 59.9%). Conclusions: Across GI malignancies, ROE was not associated with inferior DFS, PFS, or OS and was associated with lower rates of severe neurotoxicity and high-grade AEs. These findings support planned limitation of oxaliplatin exposure as a strategy to improve the therapeutic index of oxaliplatin-based chemotherapy across disease settings.

PURPOSE Hepatopancreatobiliary (HPB) cancers—including hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), pancreatic ductal adenocarcinoma (PDAC), and gallbladder cancer—are aggressive malignancies with limited treatment options and poor prognosis. The emergence of personalized liquid biopsy technologies, particularly bespoke circulating tumor DNA (ctDNA), offers new opportunities for improving clinical management. Traditional methods like imaging and tumor markers may miss early recurrence or evolving disease. This study explores the real-world application of ctDNA in HPB cancers, focusing on its use for surveillance, diagnostic clarification, treatment monitoring, and recurrence detection. Methods We retrospectively analyzed the use of a personalized ctDNA assay (Signatera, Natera) in 54 patients with HPB cancers at a single academic cancer center. The cohort included PDAC (22/54), HCC (11/54), and CCA (21/54). ctDNA was assessed longitudinally for surveillance, treatment monitoring, or diagnostic clarification. Concordance with imaging and tumor markers, as well as lead time to recurrence detection, was descriptively analyzed. RESULTS ctDNA was evaluable in 37/54 patients (84.6%), with ctDNA positivity in 22/37 (59.5%). Success rates by tumor type were 16/22 (72.7%) in PDAC, 10/11 (90.9%) in HCC, and 11/21 (52.4%) in CCA. ctDNA concordance with imaging was observed in 69/85 assessments (72.6%) and with tumor markers (carbohydrate antigen 19-9 or alpha fetoprotein) in 39/95 (41%). Clinical applications included disease surveillance (21/54, 38.9%), treatment monitoring (24/54, 44.4%), and diagnostic clarification (16/54, 29.6%). In patients with recurrence, ctDNA detected disease before imaging in several cases, with a median lead time of 28 days (range, 1 month to 7 months). CONCLUSION Personalized ctDNA testing demonstrated meaningful utility across HPB cancers, enabling early recurrence detection and guiding clinical decision making as a complementary tool in multidisciplinary care.

PURPOSE Gastroesophageal carcinoma (GEC) is increasingly managed using biomarker-guided therapies. Although both tissue DNA (tDNA) and circulating tumor DNA (ctDNA) testing are used clinically, the concordance of genomic alterations between primary tumors, metastatic sites, and liquid biopsy remains incompletely understood. METHODS We retrospectively analyzed 345 patients with GEC who underwent ctDNA testing at Mayo Clinic. tDNA next-generation sequencing and immunohistochemistry (IHC) for human epidermal growth factor receptor 2 (HER2)/erb-b2 receptor tyrosine kinase 2 ( ERBB2 ) and mismatch repair (MMR) were collected. Concordance was evaluated between ctDNA and tDNA, ctDNA and IHC, and across all three modalities, using 60-day and 30-day intervals. RESULTS Among 345 patients with ctDNA testing, 186 had tDNA testing, and 310 underwent IHC. ctDNA testing showed a shorter turnaround time than tDNA (median 6 v 13 days). The most frequent alteration in ctDNA, primary tDNA, and metastatic tDNA was TP53. Concordance between ctDNA and primary tDNA was ≥78.8% for key genes; between ctDNA and metastatic tDNA, it was ≥84.8%. IHC-ctDNA concordance was higher in metastatic tumors, with 91.1% for HER2/ ERBB2 and 97.7% for mismatch repair (MMR)/microsatellite instability (MSI) compared with 81.1% and 95.8%, respectively, in primary tumors. Triplet concordance for MSI/MMR was 97.6% in primary tumors and 100% in metastatic tumors, while ERBB2 /HER2 showed 84.4% and 93.9% concordance, respectively. ctDNA temporal heterogeneity analysis revealed 14 patients with fluctuating ERBB2 status and 3 with fluctuating MSI-H status. CONCLUSION ctDNA testing demonstrates high concordance with tDNA and IHC and offers faster turnaround. Given its minimally invasive nature and strong concordance with tissue-based testing, ctDNA is a reliable tool for genomic profiling and longitudinal monitoring in GEC.

PURPOSE For patients with advanced biliary tract cancer (BTC), cancer-related time spent in health care systems, time toxicity, represents a critical but understudied burden affecting quality of life. This study aimed to quantify time toxicity in patients receiving first-line systemic therapy and evaluate whether the addition of durvalumab to gemcitabine plus cisplatin (GC) increases health care contact time. METHODS This international, multicenter, retrospective cohort study included patients with advanced BTC seen between January 2019 and April 2024 at Mayo Clinic Enterprise (US), and between January 2021 and April 2024 at Kyorin University Hospital (Japan), and Hospital Israelita Albert Einstein (Brazil). Patients received GC plus durvalumab (GCD) or GC. Time toxicity was recorded from treatment initiation until discontinuation or last follow-up during first-line systemic therapy. Multiple regression analysis identified factors associated with high time toxicity. RESULTS Among 193 patients (102 GCD, 91 GC; median age 65 years; 50% male; 49% Eastern Cooperative Oncology Group performance status [PS] 0), median time on treatment (TOT) was 156 days (95% CI, 122 to 190). The median proportion of total time toxicity was 14.4% (IQR, 10.9-20.6). Planned visits accounted for 11.9%, while unplanned visits were infrequent (1.8%). Time toxicity strongly correlated with TOT ( r = 0.824) and progression-free survival ( r = 0.827). Despite longer treatment in the GCD group than the GC group (212 v 134 days; P = .027), total time toxicity was similar (27 v 18 days; P = .19). Younger age and poor PS were independent factors of higher time toxicity. CONCLUSION Time toxicity represents a meaningful metric that allows for more comprehensive integration of the net benefit in patients with advanced BTC with a limited lifespan.

837 Background: A recent randomized trial suggested that CR may influence ICI activity in patients with lung cancer. However, the same has not been established in GI cancers, where reports have shown mixed results with variable definitions of 'early' vs 'late' IT. We evaluated multiple approaches to assess the impact of CR on first-line ICI in GI malignancies. Methods: This retrospective study included patients from three Mayo Clinic sites (N=455). Both previously reported IT cutoffs and a new cutoff derived from ROC analysis were evaluated. Patients were categorized by the median of all ITs, the median of the first four ITs, and whether ≥20% of ITs occurred before the identified cutoff. Univariate and multivariate Cox regression (adjusting for age, MSI status, type of cancer, metastasis status, number of cycles, and receipt of chemotherapy with ICI) assessed associations with OS. KM analyses were performed to illustrate survival differences. The primary endpoint was OS. Results: When patients were categorized based on whether ≥20% of infusions occurred before 14:00 (ROC-derived cutoff), a significant association with OS was observed. On univariate analysis, early infusion timing was associated with improved survival (HR 2.30, 95% CI 1.58–3.32, p <0.001). This remained significant after multivariable adjustment (HR 2.11, 95% CI 1.41–3.16, p < 0.001). Median OS was 14.2 months in the early group vs 3.8 months in the late group (log-rank p < 0.001). Using previously defined cutoffs, categorization by the median IT of all infusions or the median of the first four infusions did not demonstrate a significant association with OS in either univariate or multivariate Cox regression analyses. Conclusions: These findings highlight the potential role of infusion timing as a chronotherapy factor in GI cancers. Given the retrospective design and heterogeneous population, prospective studies are warranted to validate this signal and clarify its clinical relevance. Baseline demographics of patients by infusion timing (early vs late). Variables Early N=412 (%) LateN=43(%) Total N=455(%) p-value Age <70 249(60.4) 21(48.8) 270 (59.3) 0.1 >70 163(39.6) 22(51.2) 185 (40.7) Gender F 118(28.6) 16(37.2) 134 (29.5) 0.3 M 294(71.4) 27(62.8) 321 (70.5) Cancer Type Gastroesophageal 109 (26.5) 8 (18.6) 117 (25.7) 0.1 Hepatocellular 159 (38.6) 24 (55.8) 183 (40.2) Biliary 86 (20.9) 4 (9.3) 90 (19.8) MSI-H 58 (14.1) 7 (16.3) 65 (14.3) Metastasis No 150 (36.4) 22 (51.2) 172 (37.8) 0.1 Yes 262 (63.6) 21 (48.8) 283 (62.2) Immunotherapy Cycle Number <6 189 (45.9) 33 (76.7) 222 (48.8) <0.001 >6 223 (54.1) 10 (23.3) 233 (51.2)

776 Background: Surgery is the only potentially curative option for PC. However, only a minority of patients (pts) undergo resection with current perioperative (periop)-chemotherapy (CT). In the absence of phase III trials, selection between mFOLFIRINOX and gemcitabine/nab-paclitaxel (gem-nab) is based on limited evidence. We assessed whether NGS–based tumor profiling can guide tailoring of CT. Methods: pts with resected PC (resectable, borderline resectable, and downstaged locally advanced) that underwent Tempus xT, xF (DNA), and/or xR (RNA) testing were selected (89% tissue, 11% blood). Most samples (73%) were collected post-CT. Samples were stratified by KRAS status into KRAS -mutated ( KRAS mut) and KRAS wild-type ( KRAS wt). PD-L1 IHC was reported as tumor proportion score (TPS). Primary endpoint was median overall survival (mOS) defined from CT initiation to death with censoring of pts alive at the last follow-up or at a study cutoff of 5 years. Secondary endpoint was molecular profiling by KRAS status. Pearson chi-square and Wilcoxon rank-sum tests were used for descriptive comparisons; univariate Cox regression and log-rank tests (p<0.05) for survival. Results: We included 1,325 pts (median age 66 years [IQR 59–72]) with resected PC [stage II (15%), stage III (12%) and stage I (10%), unknown (62%)]. 95% had adenocarcinoma. Pts received neoadjuvant (50%), neoadjuvant plus adjuvant (26%), neoadjuvant with indeterminate adjuvant allocation (13%) or adjuvant CT (11%). First-line periop-CT was mFOLFIRINOX in 73% and gem-nab in 27% (median duration 4.3 months (mo) [range, 2.6–6.7]). KRAS mutations were present in 75% (G12X 91%: G12D 44%, G12V 34%, G12R 21%, G12C <1%). mOS was 26.7 mo (95%CI, 22.4-35.7) in the total cohort; KRAS mut pts showed a clinically meaningful worse mOS compared to KRAS wt [24.1 vs 35.7 mo; HR 1.61 (95%CI, 0.98 - 2.63); p=0.06]. In the KRAS G12D pts, mFOLFIRINOX showed a trend towards longer mOS compared to gem-nab [17.79 vs 14.53 mo; HR 0.75, (95% CI, 0.56 - 1); p=0.050]; no significant differences were observed in other KRAS subgroups. Compared to KRAS wt, KRAS mut pts were enriched for TP53 (76% vs 22%; p<0.001), SMAD4 (28% vs 5.8%; p<0.001), CDKN2A (33% vs 8.5%; p<0.001), MTAP deletions (7.7% vs 1.2%; p<0.001), and chromatin-regulator alterations ( ARID1A 7.8% vs 1.2%; p<0.001; KMT2C 2.5% vs 0.6%; p=0.034). KRAS wt pts were enriched for BRAF V600E (1.5% vs 0%; p<0.001). PD-L1 TPS ≥1% was more frequent in KRAS mut compared to KRAS wt (11.0% vs 8.1%; p=0.033). Conclusions: KRAS status does not predict benefit from mFOLFIRINOX vs gem-nab in resected PC. Interestingly, resected PC showed a higher prevalence of KRAS wt compared to the metastatic setting. KRAS status is associated with distinct profiles of potentially targetable co-alterations. These findings may suggest the integration of genomic profiling in clinical trials to develop biomarker-driven tailored strategies in the early stage.