Citations

Background & Aims: To evaluate safety and efficacy of FGFR1–3 kinase inhibitor derazantinib, in advanced intrahepatic cholangiocarcinoma (iCCA) harboring FGFR2 fusions or rearrangements ( FGFR2 F ), mutations ( FGFR2 M ), or amplifications ( FGFR2 A ), previously treated with chemotherapy. Approach & Results: Open-label, non-controlled Phase 2 trial. Patients with advanced iCCA, ≥1 prior chemotherapy, and FGFR2 F (Substudy 1) or FGFR2 M /FGFR A (Substudy 2), received once-daily oral derazantinib 300 mg until disease progression, unacceptable toxicity, consent withdrawal or investigator decision to stop. Efficacy was assessed by central radiology review using RECIST v1.1. Primary endpoints were objective response rate (ORR; Substudy 1) and 3-month progression-free survival (PFS3; Substudy 2). Other endpoints were PFS, ORR (Substudy 2), disease control rate (DCR), duration of response (DOR), and overall survival (OS). In Substudy 1, ORR and DCR were 22.3% (23/103 partial responses) and 75.7%, respectively; median (95% CI) PFS was 8.1 (5.5,8.3) months, DOR was 6.5 (4.6,9.2) months, and OS was 17.2 (12.5,22.4) months. In Substudy 2, PFS3 was 63% (27/43), ORR was 9.3% (3 partial, 1 complete response), DCR was 69.8%, and OS was 11.9 (8.4,15.9) months. There were no Grade 4 or 5 drug-related events. FGFR inhibitor class-specific toxicities included drug-related hyperphosphataemia (38%, Grade 3: 3%) and dry eye (36%). Nail disorders (10%, any grade or causality), stomatitis (5%), retinal events (5%), and palmar-plantar erythrodysesthesia (1%) were infrequent. Conclusions: In previously chemotherapy treated, FGFR-inhibitor-naïve patients with iCCA harboring FGFR2 fusions, mutations, or amplifications, derazantinib showed clinically meaningful efficacy with durable objective responses, and a manageable safety profile.

Abstract Purpose: The addition of MEK inhibition (MEKi) to programmed cell death ligand 1 (PD-L1) blockade improves progression-free survival (PFS) in patients with advanced biliary tract cancer. Although MEK inhibitors may increase tumor cell immunogenicity, they can impair T-cell priming/effector function, limiting combination efficacy. We hypothesized that the addition of a CD27 agonist could restore T-cell function and enhance antitumor immunity in this combination. Patients and Methods: We conducted a randomized, phase II trial evaluating atezolizumab (840 mg, intravenously, days 1 and 15) in combination with the CD27 costimulatory monoclonal antibody [CDX-1127/varlilumab (3 mg/kg, intravenously, days 1 and 15)], with/without the addition of an MEK inhibitor [cobimetinib (60 mg, orally, daily, days 1–21, off days 22–28)] in unresectable biliary tract cancer following at least one metastatic therapy. Overall response rate (ORR) and PFS were coprimary endpoints. Treatment-related changes in CD8+ tumor-infiltrating lymphocytes (TIL) were the primary correlative outcomes. Results: The trial was closed early following interim preplanned ORR analysis. At closure, 57 patients had been enrolled [n = 29 in the cobimetinib + atezolizumab + varlilumab (CAV) arm; n = 28 in the atezolizumab + varlilumab (AV) arm]. A majority (67%) had intrahepatic cholangiocarcinoma, and 32% were immunotherapy experienced. Both regimens were well tolerated without new safety signals. Objective responses were rare [0% (CAV); 3.8% (AV)]. The median PFS (mPFS) was 2.40 (CAV) and 1.84 (AV) months [hazard ratio (HR), 0.67; 95% confidence interval (CI), 0.38–1.18]. Among immunotherapy-experienced patients, the mPFS was 3.62 (CAV) and 1.84 (AV) months (HR, 0.54; 95% CI, 0.18–1.62). Treatment with CAV increased intratumoral CD8+ T-cell density compared with treatment with AV. Conclusions: The combinations of atezolizumab and varlilumab with/without cobimetinib were safe, but neither meaningfully improved outcomes in biliary tract cancer treated in the later lines. Correlative tissue studies validated preclinical work that MEKi increases CD8+ TILs.

Abstract Background TOPAZ-1 demonstrated durvalumab + gemcitabine and cisplatin (GemCis) superiority over GemCis in first-line treatment of advanced biliary tract cancers. Real-world data from US patients and patients excluded from TOPAZ-1 (patients with autoimmune conditions [AICs] who did not receive immunotherapy) are lacking. We report real-world data for patients with cholangiocarcinoma treated with durvalumab + GemCis. Methods This retrospective, observational study enrolled adult patients diagnosed with cholangiocarcinoma in the US from the International Cholangiocarcinoma Patient Registry (ICPR) treated with first-line durvalumab + GemCis between 2021–2023. De-identified medical records from ICPR were obtained directly from consenting patients/caregivers. Patient demographics and tumor characteristics (primary objective; assessed at initial diagnosis), comorbidities, second-line treatment modalities, median real-world overall survival (mrwOS), and median real-world time to next treatment (mrwTTNT; initiation of first-line treatment and last activity in the database or death) are reported. Results Seventy patients received first-line durvalumab + GemCis: 13 (18.6%) had AIC(s) and 57 (81.4%) did not. Patient demographics, clinical characteristics, and comorbidities are shown (Table). Median (quartile 1–3) time from diagnosis to start of first-line treatment was 1.0 (0.7–1.7) months; median follow-up from first dose of first-line treatment was 7.0 (3.7–12.1) months. The mrwOS (95% CI) was 15.5 (15.1–not evaluable [NE]) months. mrwTTNT (95% CI) was 10.8 (10.4–15.7) months overall and was 20.8 (10.4–NE) months in patients who died without receiving subsequent treatment (censored at date of last activity). Among patients with AIC(s), <5 received second-line therapy (all received chemotherapy alone). Among patients with no AICs, 15 received second-line treatment; 11 (73.3%) received targeted therapy alone and <5 received chemotherapy alone. Conclusions This dataset demonstrates patients with AIC(s) are treated with durvalumab + GemCis in clinical practice. The mrwOS for durvalumab + GemCis in this patient population is consistent with TOPAZ-1 and global real-world studies.

Abstract Background & Objectives Based on the TOPAZ-I study, durvalumab combined with gemcitabine and cisplatin (GemCis) is now supported as a standard of care treatment for cholangiocarcinoma. Patients with extrahepatic cholangiocarcinoma (eCCA) often have underlying autoimmune conditions (AICs) which could restrict immunotherapy use. Treatment patterns in patients with eCCA with AICs and non-autoimmune conditions (NAICs) are reported. Method This retrospective observational analysis of adult patients diagnosed with eCCA in the United States enrolled in the International Cholangiocarcinoma Patient Registry between 2019 and 2023, focused on those treated with durvalumab. The registry contains de-identified data from medical records obtained directly from consenting patients and caregivers. Patients were followed from index date (date of eCCA diagnosis) until the last activity in the database or death. Demographics, clinical characteristics, biomarkers, treatment patterns, and adverse events (AEs) are reported. Results Overall, 135 patients with eCCA were enrolled: 24 (17.8%) had 2:1 AICs and 111 (82.2%) had NAICs. Baseline demographics were comparable between groups: the median (quartile [Q]l-Q3) age at diagnosis was 63.0 (55.0-70.0) years, the mean number of comorbidities in the overall population was 10.1, and 50.4% of patients were female. PD-Ll positivity was noted in 12.6% of patients and HER2 positivity in 10.4%. Of 91 patients with eCCA who received first-line therapy, 34 (37.4%) received GemCis alone, 27 (29.7%) chemotherapy alone (non-GemCis +/- nab-paclitaxel), 9 (9.9%) GemCis plus nab-paclitaxel, 7 (7.7%) durvalumab plus GemCis, 7 (7.7%) durvalumab monotherapy or in combination, and 7 (7.7%) other regimens. Treatment patterns by autoimmune comorbidity status are also reported (Table). Overall, 129 patients (95.6%) had ≥1 AE; fatigue was the most common (71.1%). Conclusion More patients with eCCA received a first-line durvalumab-based regimen post-March 2022 vs the full study period. The use of durvalumab as first-line treatment in this subgroup may suggest that AICs do not restrict its use.

PURPOSE EGFR alterations occur in a subset of biliary tract cancers (BTCs) and are often linked to disease progression and poor prognosis, yet targeted approaches remain underexplored. ERRFI1 , encoding the epidermal growth factor receptor (EGFR) inhibitor MIG6, is mutated in various cancers, including BTC, representing a potential predictive biomarker. We investigated whether loss of ERRFI1 function may enhance sensitivity to EGFR-targeted tyrosine kinase inhibitors (TKIs), presenting a potential therapeutic opportunity. METHODS This is a retrospective multicenter study of patients with BTC harboring ERRFI1 alterations. Data were extracted from electronic health records following institutional approval. ERRFI1 alterations were classified based on the alteration type, variant allele frequencies were documented, and coalterations were analyzed. Treatment outcomes including response, time to progression (TTP), overall survival (OS), safety profiles, and tumor marker kinetics were noted. RESULTS Fourteen BTC patients with ERRFI1 mutations were identified in our database; the median age was 50 years, 64% were males; all cases were intrahepatic cholangiocarcinomas. Common coalterations included IDH1 (36%), TP53 (29%), and ARID1A (29%). All patients received gemcitabine-cisplatin as first-line treatment, and 79% received immune checkpoint inhibitors. Eight patients (57%) received EGFR TKIs. Best responses to EGFR therapy included three partial responses (2 responses lasting >20 months), four stable diseases, and one progressive disease. The median TTP was 7 months (95% CI, 6 to 21 months). Treatment was well-tolerated: toxicities included rash (n = 2), transaminitis (n = 1), and diarrhea (n = 1). The median OS was 20 months (95% CI: 8-36 months); 50% remained alive at last follow-up. CONCLUSION ERRFI1 mutations represent actionable biomarkers in BTC, with EGFR-targeted therapy demonstrating meaningful clinical benefit in this heavily pretreated population. These findings support integration of ERRFI1 testing into routine molecular profiling of BTC and other EGFR-driven malignancies.

Background and Aims: Cholangiocarcinoma (CCA) is a rare but aggressive malignancy with poorly understood genetic susceptibility. To date, genome-wide association studies (GWAS) investigating germline variants associated with CCA risk remain limited. We aimed to identify genetic risk loci for CCA and its clinical subtypes through comprehensive GWAS and post-GWAS analyses. Approach and Results: We conducted a GWAS of 2366 CCA cases and 11,750 controls of European ancestry. Genome-wide significant loci ( p <5×10 −8 ) were identified and further examined through fine-mapping, functional annotation, and HLA imputation. Subgroup analyses were conducted by CCA subtypes and primary sclerosing cholangitis (PSC) status. Cross-trait linkage disequilibrium score regression and Mendelian randomization were employed to investigate the shared genetic architecture and potential causal relationships with a diverse range of traits. We identified 1 new genome-wide significant variant, rs535777 (OR=1.44), near HLA-DRB1/DQA1 associated with CCA, and 2 variants associated with extrahepatic CCA: rs116224263 (OR=0.17) in LINC02506 at 4p15.1 and rs6914950 (OR=1.63) near HLA-DRB1/DQB1 . Stratified analyses revealed rs2395184 (OR=3.51) near HLA-DRA/DRB5 associated with PSC-related CCA, and rs142674434 (OR=2.98) in THSD7A at 7p21.3 associated with non-PSC-related CCA. HLA imputation uncovered new amino acid residues associated with disease risk. Cross-trait analyses identified shared genetic signals between CCA and anthropometric, lipidemic, lifestyle, and medical traits. Mendelian randomization supported putative causal associations for 12 traits with CCA or its subtypes. Conclusions: Our large-scale GWAS highlights new genetic variants and HLA-linked mechanisms underlying CCA susceptibility. Integrating multi-step post-GWAS approaches enhances understanding of CCA pathogenesis and may facilitate the development of risk biomarkers for early detection and precision prevention strategies.

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 .

Abstract Purpose: Mutant IDH1 (mIDH1) defines a therapeutically targetable subtype of intrahepatic cholangiocarcinoma (ICC), with the mIDH1 inhibitor ivosidenib approved for advanced disease. A subset of patients experiences prolonged disease stabilization; however, the molecular basis for eventual progression remains poorly defined. Experimental Design: We performed molecular profiling of matched baseline and postprogression circulating tumor DNA (ctDNA) samples from patients with mIDH1 ICC enrolled in the ClarIDHy phase III trial. Functional studies were conducted to characterize candidate resistance mechanisms. Results: Longitudinal ctDNA analysis of 18 patients treated with ivosidenib for &gt;6 months revealed emergent genomic alterations in multiple cases. Acquired mutations in mitogen-activated protein kinase (MAPK) pathway genes (KRAS, NRAS, MAP2K1, NF1) were identified in five cases, with instances of concurrent alterations and/or high variant allele fractions (VAF). Additional candidate resistance events included a secondary IDH1 mutation and a hotspot IDH2 mutation, detected at low VAF in the same patient. Functional studies showed that these IDH mutations conferred sustained 2-hydroxyglutarate production and ivosidenib resistance, whereas MAPK activation blunted gene expression induced by ivosidenib plus IFNγ, a key therapeutic output of mIDH1 inhibition. In parallel, baseline ctDNA profiling of 81 patients revealed that ARID1A mutations and elevated mIDH1 VAF were associated with reduced clinical benefit. Conclusions: MAPK pathway alterations represent a recurrent mechanism of resistance to mIDH1 inhibition in ICC, whereas emergent IDH1/IDH2 mutations appear infrequent. Functional data suggest that MAPK-mediated resistance may involve impaired IFN signaling. These results support MAPK-directed combination strategies and highlight the utility of ctDNA profiling to identify predictive and resistance biomarkers in mIDH1-driven ICC.

Abstract Background Eligibility criteria for clinical trials are crucial for maintaining safety and study integrity. However, overly restrictive criteria can result in unrepresentative trial populations, leading to gaps in understanding real‐world treatment efficacy. Addressing potentially modifiable exclusions (PMEs) could enhance trial accessibility and participation without compromising safety. Methods The authors retrospectively analyzed screen‐failed patients with biliary tract cancer or pancreatic cancer between August 2019 and November 2024 at The University of Texas MD Anderson Cancer Center. Screen‐failed patients were those who provided informed consent but did not participate for any reason. Clinical data were obtained from screening logs and electronic health records. PMEs were identified and validated by two independent medical oncologists. Results Of 585 screen‐failed patients from 18 trials, 509 were analyzed (367 with pancreatic cancer and 142 with biliary tract cancer) after excluding 76 because of incomplete data. Leading causes of screen failure were declined participation (19%), comorbidities (12%), suboptimal organ function (11%), absence of a biomarker (10%), and insufficient biospecimens (7%). Reasons for declining included preference for standard care (23%), travel (22%), and competing trials (5%). The authors identified 69 patients (13.6%) who had PMEs (primarily borderline laboratory abnormalities), including liver function (23%), kidney function (20%), platelet count (12%), hemoglobin (7%), and white blood cell count (6%) abnormalities. Other PMEs included previous or concurrent malignancies (9%) and viral hepatitis (4%). PMEs were evenly distributed across trials. Conclusions Rigid eligibility criteria exclude stable patients who might benefit from investigational treatments. Easing criteria related to incidental or asymptomatic laboratory abnormalities could broaden trial accessibility and improve enrollment in populations that are more representative of real‐world use.

e23011 Background: Eligibility criteria for clinical trials are crucial for maintaining safety and study integrity. However, they often exclude patients due to medical conditions that are not relevant, leading to gaps in understanding the real-world effectiveness of treatments. Addressing potentially modifiable exclusions (PMEs) could enhance accessibility and participation in trials without compromising safety, particularly given the low rates of enrollment. Methods: We retrospectively analyzed ‘screen-failed’ patients (those who were excluded after providing consent because they did not meet the eligibility criteria or other protocol requirements) with biliary tract (BTC) or pancreatic cancer (PDAC) between August 2019 and November 2024. Screening logs and electronic health records provided clinical data. PMEs were identified and validated by two independent medical oncologists. Results: Of 585 screen-failed patients from 18 trials, 76 were excluded due to incomplete data. Among the 509 patients analyzed (367-PDAC, 142-BTC), the leading causes of screen failure were declined participation (99, 19%), comorbidities (59, 12%), suboptimal organ function (56, 11%), absence of biomarker (49, 10%), and insufficient biospecimens (36, 7%). Among patients declining participation, reasons included preference for standard care (23%), travel (22%), competing trials (5%), adverse event concerns (4%), financial issues (3%), and unknown reasons (43%). Of the 509 patients deemed ineligible for study entry at screening, we identified 69 patients (13.6%) with PMEs, primarily related to borderline laboratory abnormalities: liver function (16, 23%), kidney function (14, 20%), platelet count (8, 12%), hemoglobin (5, 7%), and white blood cell count (4, 6%). Other PMEs included previous or concurrent malignancies (6, 9%) and viral hepatitis (3, 4%). PMEs were evenly distributed across trials. Notably, all screen-failed patients proceeded to receive standard therapy. Conclusions: This analysis underscores the potential for rigid eligibility criteria to exclude stable patients who might benefit from investigational treatments. Easing specific criteria, particularly those related to laboratory abnormalities, could broaden trial accessibility. Furthermore, examining the reasons for declined participation and addressing PMEs could help develop strategies to enhance trial enrollment.