Mahipal, Amit

605 Background: Multiple treatment modalities are available for localized hepatocellular carcinoma (HCC), and current Barcelona Clinic Liver Cancer (BCLC) guidelines recommend ablation for patients with a limited number of small tumors, not amenable to resection or transplantation. However, in recent years, stereotactic body radiation therapy (SBRT) has been increasingly used for localized disease. Patient outcomes based on treatment modality are not well understood. Methods: We conducted a retrospective analysis using the National Cancer Database (NCDB) to identify patients with a history of stage I/II HCC with tumors ≤ 5 cm who had received local therapy with either radiofrequency ablation (RFA) or SBRT between 2006 and 2021. A propensity score matched analysis was conducted accounting for patient demographics, facility region and tumor level characteristics, as well as an inverse probability of treatment weight-adjusted (IPTW) analysis. Overall survival was estimated using the Kaplan-Meier method. Results: We identified 14,516 patients meeting inclusion criteria, including 13,036 who received RFA and 1,480 who received SBRT. Demographic factors associated with receipt of SBRT included age >50 years, female sex, and treatment in the Middle Atlantic and East North Central regions, as well as clinical factors including larger tumor size (>3 to 5 cm), severe fibrosis/cirrhosis, and stage II disease ( p <0.05 for all). Factors associated with receipt of RFA include black race, higher Charlson-Deyo Comorbidity Scores, treatment at a comprehensive cancer program or integrated network cancer program, and treatment in the East South Central, West North Central, West South Central, Mountain, and Pacific Regions ( p <0.05 for all). Median time from diagnosis to treatment initiation was longer for those who received SBRT (66.3 vs 84.6 days, p <0.001). In a propensity matched analysis, mOS was 45.1 months for those receiving RFA vs 30.8 months for those receiving SBRT ( p <0.001). An IPTW analysis showed similar survival benefit with RFA over SBRT (mOS 51.0 vs 30.5 months, p <0.001). This OS benefit was observed in subset of patients with tumors <3cm in size. Conclusions: In this propensity matched analysis controlling for relevant patient and tumor factors, RFA was associated with improved survival. Prospective studies will be important to further analyze differences in patient outcomes.

567 Background: IDH2 mutation is rare (1%) in patients (pts) with cholangiocarcinoma and there are no data on prognosis in these pts and response to first line (1L) chemotherapy or off-label IDH2 inhibitor enasidenib. Methods: This IRB approved retrospective study included consecutive pts 18 years or older with IDH2 mutated biliary cancer identified between 2010-2024 at 4 large academic centers. Pt characteristics, systemic therapy(ies), next-generation sequencing (NGS) and survival data were obtained via review of electronic medical records. Survival probabilities were estimated using the product-limit method of Kaplan-Meier using SAS (v9.4, Cary, NC). Results: In 40 pts who met criteria, 9 (22.5%) underwent curative intent resection/ ablation, 34 (85%) had recurrent or de novo locally advanced or metastatic stage and of them 33 (82.5%) received any therapy for advanced cancer. Of these 33 pts, 25 (75.7%) were female, 29 (87.9%) non-Hispanic White and 32 (97%) had intrahepatic subtype with a median (range) age of 65 (28-82) years. NGS on tissue (51.5%), plasma (21.2%) or both tissue and plasma (27.3%) identified IDH2 R172* in 28 (84.8%), I98T in 1 (3%), F278fs in 1 (3%) pts and not reported/missing in 1 (3%) pt. Most common co-altered genes included TP53 (27.5%), ARID1A (17.5%), PBRM1 (12.5%), CDKN2A (10%), BAP1 (10%). FGFR2 fusion or N/KRAS mutation was present in 2 (5%) pts each. Of 33 pts with advanced stage, 1L therapy was gemcitabine/platinum +/- devimistat or durvalumab in 84.9%. Median (95% CI) progression-free survival (PFS) on 1L chemotherapy and overall survival were 6.6 (4.1-7.8) and 16.3 (12.1-28.9) months, respectively. Eight of 33 (24.2%) pts with advanced stage received off label enasidenib as Nth line therapy with median PFS (95% CI) 3.9 (1.1-5.1) months. Conclusions: Most pts with IDH2 mutation had advanced ds with median survival similar to those with IDH1 mutated advanced cholangiocarcinoma. Off label enasidenib had modest benefit in this rare subset of pts and should be investigated further.

566 Background: FGFR inhibitors (FGFRi) have an established role in treating FGFR2-altered (alt) cholangiocarcinoma (CCA). Tinengotinib, a novel FGFRi, has shown promising activity overcoming acquired resistance to prior FGFRi. We present biomarker analyses evaluating tinengotinib’s ability to overcome prior FGFRi resistance and to elucidate mechanism of resistance to tinengotinib. Methods: Eligible patients (pts) with advanced/metastatic CCA who had received ≥ 1 prior systemic chemotherapy were treated with tinengotinib 10 mg daily across 4 Cohorts: A1: FGFR2 fusion (fus) with primary progressive disease (PD) on prior FGFRi; A2: FGFR2 fus with PD after prior response to FGFRi; B: FGFR alt without FGFR2 fus; C: FGFR wild-type. Efficacy was assessed by RECIST v1.1. All pts underwent liquid biopsy for circulating tumor DNA (ctDNA) at baseline; additional timepoints include cycle 3 day 1 (C3D1), time of PD, and end of treatment (EOT). Samples were analyzed using FoundationOne Liquid panel. Results: 27 out of 55 enrolled pts had biomarker samples collected at baseline and C3D1. Among them, pts in A1 (n=10, 107 mutations (mut)), B (n=8, 90 mut) and C (n=5, 74 mut) showed a significant decrease in short variant allele frequencies (VAF) from baseline to C3D1 by a median relative VAF reduction of 100% (p<0.0001) for each of the three cohorts. Although a median relative VAF reduction of 33.3% was seen in A2 (n=4, 15 mut), this was not significant (p=0.6093) likely due to low baseline mutation burden. A ≥50% reduction in ctDNA was associated with improved progression free survival (p<0.0014). Additionally, 100% of median relative reductions in FGFR2 kinase domain (KD) mut were seen in A1 and B (p<0.0001, 95% CI 100-100% and p=0.0156, 95% CI 83.6-100%, respectively), with 92% and 57% clearance of initial FGFR2 KD mut by C3D1. In a subgroup of 10 pts with biomarker sampling at baseline and EOT, 3 pts in A1 with acquired resistance showed emergence of novel FGFR2 mut, loss of FGFR-sensitive mut and new mut in alternate pathways (e.g., AKT, EGFR, RAS/MAPK) while retaining the original FGFR2 fus. 1 pt from B developed resistance due to new FGFR2 rearrangements and FGFR2 mut. 4 FGFR wild-type pts from C developed resistance involving mut in TP53, KRAS, and other oncogenic drivers. Conclusions: These findings provide genomic evidence that tinengotinib may overcome resistance to prior FGFRi treatment in FGFR2 fus-positive CCA, as reflected by significantly reductions in ctDNA VAFs and frequent clearance of FGFR2 KD mutations. The emergence of resistance alterations including de novo FGFR2 mutations and bypass pathways activations indicates acquired resistance that may limit long-term benefit. These results support further investigation with expanded biomarker sampling to better characterize resistance evolution and guide therapy optimization in an ongoing Phase 3 trial. Clinical trial information: NCT04919642 .

561 Background: For patients with aHCC, second-line treatment options are not well established. The primary aim of this study was to evaluate the efficacy of Futi, an FGFR 1-4 inhibitor, in combination with Pem as a second line therapy in patients with FGF19-expressing aHCC. Methods: Patients aged ≥ 18 years, with histological/cytological diagnosis or radiological diagnosis of HCC, Child-Pugh (CP) class A-B7, Barcelona Clinic Liver Cancer (BCLC) A, B or C, ECOG performance status of 0-2, and FGF19+, by in-situ hybridization or immunohistochemistry, received Futi 20 mg once daily plus i.v. Pem 200mg every 3 weeks. The primary endpoint was progression-free survival at 6 months (PFS6). Secondary endpoints include overall survival (OS). The study was designed to enroll 22 evaluable patients to detect PFS6 from 25% (historical control) to 47%, assuming a 1-sided alpha of 0.1 with 80% power. All patients provided written consent. Eligible patients with consent who started treatment are considered evaluable. Results: The study was closed to enrollment early at the request of funding agency due to poor accrual. Between 8/2021 and 3/2024, 14 patients enrolled with 1 patient withdrawing consent before beginning protocol treatment. Among 13 evaluable patients, median age was 72 (range: 60-87) years, 7 (53.8%) were male, 12 CP A (92.3%), 7 BCLC C (53.8%), with 7 (53.8%) having received prior liver directed therapy. Median PFS was 15 weeks (95% confidence interval [CI]: 9.0-Not Estimable) and PFS6 was 23.1% (95% CI: 8.6%, 62.3%). Objective response rate was 0% (95% CI: 0%, 24.71%) and stable disease occurred in 7 (53.9%) of patients. Median OS was 55.7 weeks (95% CI: 47.3-NE). Nine (69.2%) patients experienced at least 1 grade 3+ adverse event (AE), and 2 (15.4%) patients experienced at least a grade 4+ AE. One patient had a grade 5 AE unrelated to study treatment (acute kidney injury). Most commonly reported AEs (occurring in more than 31% of patients) were hyperphosphatemia (76.9%), fatigue (69.3%), diarrhea (61.6%), AST (53.9%) and ALT (46.2%), dry eye (38.5%), nail changes (38.5%), rash-maculo-papular (38.5%), and mucositis oral (38.5%). Conclusions: This prospective study evaluated the use of a targeted treatment in combination with immunotherapy following first line immune-based therapy. This combination had modest activity as a second line therapy for patients with aHCC but did not meet the primary endpoint. The safety profile was acceptable and consistent with prior reports. An optimal second-line regimen remains a critical need. Clinical trial information: NCT04828486 .

Background: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have advanced the treatment of type 2 diabetes mellitus (T2DM), yet their association with cancer risk remains subject of ongoing research. Chronic pancreatitis (CP) is a well-established risk factor for pancreatic cancer, yet the impact of GLP-1 RA therapy in this high-risk population is unknown. In this study, we aimed to evaluate the association between GLP-1 RA use and pancreatic cancer incidence among patients with CP, and among those with CP and T2DM. Methods: We performed a retrospective cohort study using data from TriNetX, a healthcare database of over 150 million patients in the United States. In the first analysis, adult patients with pre-existing CP were identified and stratified by use of a GLP-1 RA (semaglutide, dulaglutide, tirzepatide, exenatide, liraglutide, lixisenatide, and albiglutide). Propensity score matching (PSM) was conducted between GLP1-RA users and non-users, matching for age, sex, race, tobacco use, alcohol use, hypertension, hyperlipidemia, obesity, and pancreatic cysts. Five-year incidence of pancreatic cancer was compared between GLP-1 RA users and non-users in the matched cohort between 2015 and 2025. We then restricted the cohort to patients with CP and T2DM and repeated this analysis. Results: We identified 89,596 patients with CP, including 3183 GLP-1 RA users and 86,413 non-users. After PSM, GLP-1 RA use was associated with a lower 5-year incidence of pancreatic cancer (hazard ratio (HR) 0.49, 95% confidence interval (CI) 0.30–0.80, p < 0.005). Similarly, amongst patients with CP and T2DM, GLP-1 RA use was associated with a lower 5-year incidence of pancreatic cancer (HR 0.53, 95% CI 0.31–0.91, p < 0.05). Conclusions: GLP-1 RA use was associated with a significantly reduced incidence of pancreatic cancer in all patients with CP, as well as the subpopulation with both CP and T2DM. Given the elevated cancer risk in CP, these findings suggest a potential beneficial effect of GLP-1RA use in this high-risk population. Prospective studies will be important to further analyze and confirm this potential benefit.

Abstract Central nervous system (CNS) tumors often harbor alterations in genes regulating key cellular pathways, including fibroblast growth factor receptor (FGFR) genes. Here, we report the efficacy and safety of treatment with pemigatinib, an oral, potent, selective FGFR1-3 inhibitor, in patients with advanced FGFR-altered CNS tumors. FIGHT-207 was a single-arm, open-label, phase 2 study of pemigatinib in patients with advanced solid tumors harboring FGFR fusions/rearrangements or other mutations. Patients received pemigatinib 13.5 mg once daily until disease progression or unacceptable toxicity. Endpoints included tumor response and safety. Of the 13 patients with CNS tumors in FIGHT-207, 10 had glioblastoma. Fibroblast growth factor receptor alterations were FGFR3-TACC3 fusions (n = 9), FGFR1 K656E mutations (n = 2), FGFR1 N546K mutation (n = 1), and FGFR1-MITF fusion (n = 1). Three patients (23%) displayed objective responses (1 complete, 2 partial). Safety was consistent with the overall FIGHT-207 population. Pemigatinib had antitumor activity and a manageable safety profile in patients with CNS tumors.

Abstract Background Unresectable hepatocellular carcinoma (uHCC) is a leading cause of cancer death. FDA-approved first-line systemic therapies include atezolizumab/bevacizumab (atezo/bev) and durvalumab/tremelimumab (durva/treme); however, there is a lack of comparative data. Methods We reviewed outcomes of patients with uHCC who initiated atezo/bev or durva/treme between 2017 and 2024, across six institutions. Overall survival (OS) and time to treatment discontinuation (TTD) were analyzed using the Kaplan–Meier and Cox models, adjusting for baseline characteristics. Results Four hundred fifty-two uHCC pts were included. Median age: 68 years; 77% male; 81% white. Most common etiologies were viral hepatitis (38.9%) and metabolic dysfunction-associated steatohepatitis (19.5%). Disease progression was the primary reason for treatment discontinuation, atezo/bev (56%) and durva/treme (42%). Outcomes were not statistically significant (median OS [month, m]: 14.0 vs 14.6 [P = .66]; median TTD [m]: 4.9 vs 3.9 [P = .42] for atezo/bev vs durva/treme). Outcomes were significantly different between Child-Pugh classes (CP: A, B7, B8/9, C) respectively, median OS(m): 19.0, 6.1, 5.1, 2.0 (P &lt; .001); median TTD(m): 6.1, 2.3, 3.0, 1.3 (P &lt; .001). Conclusions In this real-world study of uHCC, no significant difference in clinical outcomes was observed between atezo/bev and durva/treme in the first-line setting. CP scores were a key prognostic variable with both regimens.

Importance The prognosis of advanced pancreaticobiliary tumors is poor. Next-generation sequencing (NGS) of tissue samples is utilized to identify actionable alterations, but there are occasional limitations due to inadequate tissue acquisition. Circulating tumor DNA (ctDNA) is an alternative method, but its correlation with tissue-based NGS remains unexplored. Objectives To assess the mutation concordance (mCR) rates between ctDNA and tissue testing for patients with pancreatic ductal adenocarcinoma (PDAC) and cholangiocarcinoma (CC) and to evaluate how ctDNA performs as a treatment response biomarker. Design, Setting, and Participants This retrospective cohort study was conducted among patients with PDAC and CC treated at academic institutions from January 2014 to January 2025. Patients underwent ctDNA testing using 1 platform and tissue NGS testing using 2 platforms. Main Outcomes and Measures mCR, which measures the shared gene alterations observed by both ctDNA and tissue-based NGS testing, was calculated using the Spearman correlation for PDAC and CC. The performance of ctDNA as a treatment response biomarker was assessed by comparing serial ctDNA data with restaging scans and cancer antigen 19-9 levels in patients with PDAC. Results Our cohort included 790 patients: 570 with advanced PDAC (265 [46.5%] female; median [IQR] age, 64 [33-84] years) and 220 with advanced CC (95 [43.2%] female; median [IQR] age, 66 [42-88] years). Overall, 461 patients with PDAC (80.9%) and 192 patients with CC (87.2%) underwent ctDNA testing, while 239 patients with PDAC (41.9%) and 70 patients with CC (31.8%) had tissue NGS testing. Among patients with PDAC, 85 of 130 patients (65.4%) showed shared specific gene alterations between ctDNA and tissue testing; there was a significant mCR, with a Spearman correlation of 0.47 (95% CI, 0.28-0.62; P &amp;lt; .001). For patients with CC, 32 of 48 (66.7%) had shared alterations between ctDNA and tissue testing; there was a significant mCR, with a Spearman correlation of 0.56 (95% CI, 0.35-0.70; P &amp;lt; .001). A subgroup analysis of patients with PDAC who underwent serial ctDNA testing suggested that new TP53 subclones and increased ctDNA variant allele frequency levels of TP53 and KRAS were associated with higher odds of progressive disease (eg, increased TP53 frequency: odds ratio, 7.28; 95% CI, 2.15-24.66; P = .001). Conclusions and Relevance In this cohort study of patients with pancreaticobiliary tumors, there was a significant mCR between ctDNA and tissue NGS testing. Additionally, results suggest that ctDNA might detect resistant clones and enable assessment of treatment response.

4123 Background: Atezolizumab plus bevacizumab is the most commonly utilized first-line therapy for advanced HCC. However, the optimal choice for second-line treatment remains uncertain, particularly between different tyrosine kinase inhibitors including lenvatinib and cabozantinib. This study aims to compare survival outcomes of patients with metastatic HCC who received either lenvatinib or cabozantinib as second-line therapy following frontline treatment with atezolizumab plus bevacizumab. Methods: This retrospective cohort study utilized the TriNetX database, a large-scale platform providing access to deidentified electronic medical records from over 130 million patients across 94 healthcare organizations in the United States. The study included patients diagnosed with metastatic HCC (ICD-10 codes: C22, C22.8) who were aged 18 years or older, diagnosed between January 2019 and October 2024, and had received first-line chemotherapy with atezolizumab and bevacizumab. The cohort was divided into two groups: one receiving lenvatinib and the other cabozantinib as second-line therapy. The primary outcome was overall survival (OS), compared between the two treatment groups using 1:1 propensity score matching (PSM) to balance baseline demographics and comorbidities. Kaplan-Meier survival analysis, log-rank tests, and hazard ratios (HR) were employed to assess differences in OS. Results: Between January 2019 and October 2024, a total of 552 patients met the study criteria, including 397 patients who received Lenvatinib and 155 patients who received cabozantinib as second-line therapy. Median age was similar in two groups (65.2 vs 65.9 yrs). There were no differences between the two groups with respect to gender, albumin or bilirubin levels. Lenvatinib group had lower proportions of white patients (44.1% vs 55.3%). After PSM (matched on age, race, gender, albumin and bilirubin), the final analysis included 151 patients in each treatment group. Kaplan-Meier survival curves demonstrated no statistically significant difference in OS between the two groups (median OS: 16.6 vs 10.9 months; HR: 0.809; 95%CI: 0.576-1.136; p=0.597). Conclusions: This retrospective cohort study found no significant difference in OS in pts with metastatic HCC treated with lenvatinib or cabozantinib as second-line therapy following atezolizumab plus bevacizumab. These findings suggest that both agents may offer comparable survival benefits, highlighting the need for further prospective studies to refine second-line treatment strategies for advanced HCC.