Azad, Nilofer S.

TPS587 Background: Biliary tract cancer (BTC) is characterized by generally poor prognoses with limited treatment options. Systemic chemotherapy usually begins with gemcitabine, platinum agents, and a checkpoint inhibitor followed by 5-FU and oxaliplatin, irinotecan or a taxane. Presently, there is no consensus second-line therapy for patients with BTC. The DLL/Notch signaling pathway has been described to be a major driver of cholangiocarcinogenesis and VEGF-A overexpression has been reported in BTC tumors, correlating with stage, metastasis, and prognosis of the disease. CTX-009 is a recombinant bispecific antibody that binds both delta-like ligand-4 (DLL4) and vascular endothelial growth factor A (VEGF-A). The antibody simultaneously inhibits the DLL4-Notch 1 and VEGF A-VEGF receptor signaling pathways. Methods: COMPANION-002 (CTX-009 -002) is an open-label, randomized, controlled study in patients in second line advanced or metastatic BTC. To be eligible, patients must have radiologically documented progression after a prior gemcitabine and platinum containing chemotherapy regimen as first line therapy for locally advanced unresectable or metastatic disease. 150 patients will be randomized in a 2:1 ratio to receive either CTX-009 plus paclitaxel or paclitaxel alone. The stratification factors to be used at randomization include stage (locally advanced vs. metastatic), anatomic subsite of primary tumor (intrahepatic cholangiocarcinoma vs. other, i.e. extrahepatic cholangiocarcinoma, gallbladder, or ampullary), and Eastern Cooperative Oncology Group (ECOG) Performance status (0 vs. 1). Patients will be treated in 28-day cycles, with CTX-009 administered at 10 mg/kg IV on Day 1 and 15, and paclitaxel administered at 80 mg/m2 on days 1, 8, and 15. The patients randomized to paclitaxel arm can crossover after disease progression if selection criteria continue to be met. The primary objective of the study is to assess the efficacy of CTX-009 in combination with paclitaxel vs. paclitaxel alone, as measured by Overall Response Rate (ORR) assessed by an Independent Central Radiology (ICR) review. Key secondary objectives include overall survival, progression-free survival, and duration of response. Clinical trial information: 251040.

4084 Background: Treatment of advanced CCA has changed dramatically over the past five years with the advent of molecularly targeted therapy, now approved in the 2nd line and beyond. However, real world utilization of molecular profiling and targeted therapy is still unknown and these data are critical to empower treatment decision-making. Methods: In 2019, the Cholangiocarcinoma Foundation (CCF) and Ciitizen (a wholly owned subsidiary of Invitae Corporation) collaboratively launched a registry platform that directly consents patients and collects comprehensive medical records. De-identified data including clinical characteristics, molecular testing, interventions, and outcomes are extracted and standardized for research use. The data is longitudinal with regularly planned updates; registry participants can be re-engaged to obtain additional data and communicate tailored insights. Results: We quantified the rate of molecular testing, the presence of targetable biomarkers, and the utilization and outcomes on matched targeted therapies for 372 individuals with CCA. 328 (88.2%) individuals had molecular testing, with the identified targetable mutations and matched therapies reported. Of 328 individuals who had molecular testing, 111 (33.8%) individuals had one or more targetable mutations (116 mutations total). Only 46% (51) of individuals with targetable mutations received targeted therapy. Of the 54% (60) individuals with targetable mutations that did not receive any matched therapy, the majority (61.7%, 37) were in early disease or first line of treatment and therefore not yet eligible for targeted therapy. These individuals will be informed that based on their molecular profile, a targeted therapy may be an option, and suggest they discuss with their treating physician. Conclusions: A novel prospectively-maintained database registry for CCA has been formed in collaboration between a patient advocacy organization (CCF) and industry (Invitae). Prevalence of actionable biomarkers was higher than historically expected and may reflect patient utilization bias of the registry platform. Molecular profiling and access to targeted therapeutics remains suboptimal at this time in CCA. Future directions for the registry include identifying and targeting disparities in care and supporting biopharmaceutical development and regulatory decisions. [Table: see text]

Abstract Background: Isocitrate dehydrogenase 1/2 (IDH1/2) is mutated in a subset of cholangiocarcinoma (CCA), gliomas, and other solid tumors. LY3410738 is a potent, selective, covalent, dual inhibitor of IDH1/2 mutations (IDH1/2m). LY3410738 binds covalently at a novel binding site, enabling continued potency in preclinical models in the setting of second site IDH resistance mutations. We present initial results from the first-in-human phase 1 study of oral LY3410738 in patients (pts) with IDH1/2m CCA, and IDH1m glioma or other solid tumors. Methods: Dose escalation (3+3 design) evaluated LY3410738 monotherapy in advanced IDHm CCA and other solid tumors (NCT04521686). Key objectives included determining the RP2D, safety, PK, PD (inhibition of plasma D-2-HG), and preliminary antitumor activity. Results: As of 28 July 2022, 80 pts including 42 with CCA (33 IDH1m, 9 IDH2m), 27 with glioma (IDH1m), and 11 other tumor types (IDH1m) received LY3410738 dosed at 25-600 mg QD or 300 mg BID. Pts were median 52 years of age (range, 23-80) with a median of 2 prior therapies (range, 1-7). 19% of CCA pts had received prior IDH1 inhibitor. Median time on treatment was 3.7 months (range, 0.1-19). No DLTs or treatment related deaths were observed; the MTD was not reached. Treatment emergent adverse events (TEAEs) ≥15% included nausea (35%), vomiting (21%), and decreased appetite (19%) and were mostly grade 1-2. Most frequent grade ≥3 TEAEs >2% were anemia (4%), cholangitis (3%), headache (3%), decreased lymphocyte count (3%), and hyponatremia (3%). LY3410738 exposure was dose proportional. In pts with IDH1m cancers, LY3410738 achieved sustained D-2-HG inhibition at all dose levels, including in pts who received prior IDH1 inhibitor. In pts with IDH2m cancers, a higher dose (≥150 mg daily dose) was required for D-2-HG inhibition. Among the 42 pts with R/R CCA, the best response included 1 PR and 22 SD. Of the 22 glioma pts with contrast enhancing tumors, best response included 3 PR and 9 SD. Conclusions: LY3410738 demonstrated a favorable safety profile with potent and sustained D-2-HG inhibition in pts with IDH1/2m advanced solid tumors. Consistent with the expectations for IDH inhibitor monotherapy in this setting, CCA and glioma pts exhibited prolonged stable disease. RP2D evaluation is ongoing. Updated data on LY3410738 monotherapy will be presented at the meeting. Citation Format: Jordi Rodon, Lipika Goyal, Teresa Macarulla Mercade, Masafumi Ikeda, Shunsuke Kondo, Do-Youn Oh, Li-Yuan Bai, Makoto Ueno, Antoine Italiano, Kyriakos Papadopoulos, David Spigel, Sani H. Kizilbash, Rasha Cosman, Joon Oh Park, Li-Tzong Chen, Tomoya Yokota, Anita A. Turk, Chih-Yi Liao, Rachna Shroff, Anthony El-Khoueiry, Taroh Satoh, Antoine Hollebecque, Mitesh J. Borad, Nilofer Azad, Kurt A. Jaeckle, Herbert H. Loong, Jorge Adeva, Wei Peng Yong, Junjie Zhao, Hui Liu, Anna M. Szpurka, Ivelina Gueorguieva, Kamnesh R. Pradhan, Xiaojian Xu, James J. Harding. A first-in-human phase 1 study of LY3410738, a covalent inhibitor of mutant IDH, in advanced IDH-mutant cholangiocarcinoma and other solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr CT098.

Background and Aims: Biliary tract cancers are rare, heterogeneous cancers with poor prognoses. Bintrafusp alfa, a first-in-class bifunctional fusion protein composed of the extracellular domain of TGF-βRII (a TGF-β “trap”) fused to a human IgG1 monoclonal antibody blocking programmed death ligand 1, was evaluated in patients with locally advanced/metastatic chemorefractory biliary tract cancers. Approach and Results: This multicenter, single-arm, open-label, phase 2 study (NCT03833661) enrolled adults with locally advanced or metastatic biliary tract cancer that was intolerant to or had failed first-line systemic platinum-based chemotherapy. Patients received 1200 mg bintrafusp alfa intravenously Q2W. The primary endpoint was confirmed objective response according to Response Evaluation Criteria in Solid Tumors 1.1 assessed by IRC. Secondary endpoints included duration of response, durable response rate, safety, progression-free survival, and overall survival. Between March 2019 and January 2020, 159 patients were enrolled. Median follow-up was 16.1 (range, 0.0–19.3) months; 17 patients (10.7%; 95% CI: 6.4%–16.6%) achieved an objective response. Median duration of response was 10.0 (range, 1.9–15.7) months; 10 patients (6.3%; 95% CI: 3.1%–11.3%) had a durable response (≥6 mo). Median progression-free survival was 1.8 months (95% CI: 1.7–1.8 mo); median overall survival was 7.6 months (95% CI: 5.8–9.7 mo). Overall survival rates were 57.9% (6 mo) and 38.8% (12 mo). Grade ≥3 adverse events occurred in 26.4% of patients, including one treatment-related death (hepatic failure). Frequent grade ≥3 adverse events included anemia (3.8%), pruritus (1.9%), and increased alanine aminotransferase (1.9%). Conclusions: Although this study did not meet its prespecified primary endpoint, bintrafusp alfa demonstrated clinical activity as second-line treatment in this hard-to-treat cancer, with durable responses and a manageable safety profile.

Abstract Background Previous studies report increasing cholangiocarcinoma (CCA) incidence up to 2015. This contemporary retrospective analysis of CCA incidence and mortality in the US from 2001-2017 assessed whether CCA incidence continued to increase beyond 2015. Patients and Methods Patients (≥18 years) with CCA were identified in the National Cancer Institute Surveillance, Epidemiology, and End Results 18 cancer registry (International Classification of Disease for Oncology [ICD-O]-3 codes: intrahepatic [iCCA], C221; extrahepatic [eCCA], C240, C241, C249). Cancer of unknown primary (CUP) cases were identified (ICD-O-3: C809; 8140/2, 8140/3, 8141/3, 8143/3, 8147/3) because of potential misclassification as iCCA. Results Forty-thousand-and-thirty CCA cases (iCCA, n=13,174; eCCA, n=26,821; iCCA and eCCA, n=35) and 32,980 CUP cases were analyzed. From 2001-2017, CCA, iCCA, and eCCA incidence (per 100 000 person-years) increased 43.8% (3.08 to 4.43), 148.8% (0.80 to 1.99), and 7.5% (2.28 to 2.45), respectively. In contrast, CUP incidence decreased 54.4% (4.65 to 2.12). CCA incidence increased with age, with greatest increase among younger patients (18-44 years, 81.0%). Median overall survival from diagnosis was 8, 6, 9, and 2 months for CCA, iCCA, eCCA, and CUP. From 2001-2016, annual mortality rate declined for iCCA (57.1% to 41.2%) and generally remained stable for eCCA (40.9% to 37.0%) and for CUP (64.3% to 68.6%). Conclusions CCA incidence continued to increase from 2001-2017, with greater increase in iCCA versus eCCA, whereas CUP incidence decreased. The divergent CUP versus iCCA incidence trends, with overall greater absolute change in iCCA incidence, provide evidence for a true increase in iCCA incidence that may not be wholly attributable to CUP reclassification.

PURPOSE Biliary tract cancers (BTCs) are aggressive cancers that carry a poor prognosis. An enhanced understanding of the immune landscape of anatomically and molecularly defined subsets of BTC may improve patient selection for immunotherapy and inform immune-based combination treatment strategies. METHODS We analyzed deidentified clinical, genomic, and transcriptomic data from the Tempus database to determine the mutational frequency and mutational clustering across the three major BTC subtypes (intrahepatic cholangiocarcinoma [IHC], extrahepatic cholangiocarcinoma, and gallbladder cancer). We subsequently determined the relationship between specific molecular alterations and anatomical subsets and features of the BTC immune microenvironment. RESULTS We analyzed 454 samples of BTC, of which the most commonly detected alterations were TP53 (42.5%), CDKN2A (23.4%), ARID1A (19.6%), BAP1 (15.5%), KRAS (15%), CDKN2B (14.2%), PBRM1 (11.7%), IDH1 (11.7%), TERT (8.4%), KMT2C (10.4%) and LRP1B (8.4%), and FGFR2 fusions (8.7%). Potentially actionable molecular alterations were identified in 30.5% of BTCs including 39.1% of IHC. Integrative cluster analysis revealed four distinct molecular clusters, with cluster 4 predominately associated with FGFR2 rearrangements and BAP1 mutations in IHC. Immune-related biomarkers indicative of an inflamed tumor-immune microenvironment were elevated in gallbladder cancers and in cluster 1, which was enriched for TP53, KRAS, and ATM mutations. Multiple common driver genes, including TP53, FGFR2, IDH1, TERT, BRAF, and BAP1, were individually associated with unique BTC immune microenvironments. CONCLUSION BTC subtypes exhibit diverse DNA alterations, RNA inflammatory signatures, and immune biomarkers. The association between specific BTC anatomical subsets, molecular alterations, and immunophenotypes highlights new opportunities for therapeutic development.

PURPOSEAn ASCO provisional clinical opinion offers timely clinical direction to ASCO's membership following publication or presentation of potentially practice-changing data from major studies. This provisional clinical opinion addresses the appropriate use of tumor genomic testing in patients with metastatic or advanced solid tumors.CLINICAL CONTEXTAn increasing number of therapies are approved to treat cancers harboring specific genomic biomarkers. However, there is a lack of clarity as to when tumor genomic sequencing should be ordered, what type of assays should be performed, and how to interpret the results for treatment selection.PROVISIONAL CLINICAL OPINIONPatients with metastatic or advanced cancer should undergo genomic sequencing in a certified laboratory if the presence of one or more specific genomic alterations has regulatory approval as biomarkers to guide the use of or exclusion from certain treatments for their disease. Multigene panel–based assays should be used if more than one biomarker-linked therapy is approved for the patient's disease. Site-agnostic approvals for any cancer with a high tumor mutation burden, mismatch repair deficiency, or neurotrophic tyrosine receptor kinase ( NTRK) fusions provide a rationale for genomic testing for all solid tumors. Multigene testing may also assist in treatment selection by identifying additional targets when there are few or no genotype-based therapy approvals for the patient's disease. For treatment planning, the clinician should consider the functional impact of the targeted alteration and expected efficacy of genomic biomarker–linked options relative to other approved or investigational treatments. Additional information is available at www.asco.org/assays-and-predictive-markers-guidelines .

4023 Background: Biliary tract cancers (BTC) are increasingly subtyped by molecular alterations, but little is known about the relationship between gain-of-function mutations and the RNA transcript expression of immune-related pathways. Methods: A sample of retrospective, clinicogenomic and transcriptomic data from de-identified records of patients with BTC in the Tempus database was selected. We then investigated the relationship between the mutational landscape and immune-related RNA signatures of different anatomic and genomic BTC subtypes. Results: The cohort included 455 samples of intrahepatic bile duct (IH) (n=267), gallbladder (GB) (n=153), and extrahepatic bile duct (EH) (n=35) cancer subtypes. Across all subtypes, we detected alterations in TP53 (43.8%), ARID1A (19.8%), KMT2C (18.2%), BAP1 (14.6%), KRAS (12.7%), TERT (12.0%), IDH1 (11.4%), KMT2D (11.0%), LRP1B (11.0%), and PBRM1 (10.7%), along with FGFR2 fusions (2.6%). Potentially actionable biomarkers ( FGFR2 and NTRK1-3 fusions, IDH1 and BRAFV600E mutations, tumor mutational burden [TMB]>10, HER2 expression, and/or microsatellite instability) were identified in 21.1% of all BTC and 28.6% of IH samples. Mutually exclusive alterations observed between subtypes were TP53 & BAP1, KRAS & BAP1, TP53 & IDH1, KRAS & IDH1, and SMAD4 & BAP1 ( P < 0.001 for all). GB was more inflamed based on RNA signatures and classical immune biomarkers, including PD-L1 and TMB. RNA signature analyses revealed a higher expression of immune-related pathways in GB than IH ( P = 0.001) with no differences in comparison with EH. PD-L1 expression and continuous TMB were elevated in GB versus the other anatomical subtypes. Significant associations were noted between particular genetic mutations and immune profiling features (table). Conclusions: BTC subtypes are diverse in DNA alterations, RNA inflammatory signatures, and immune markers. Notably, potentially actionable biomarkers were identified in a sizable portion of the cohort and varied significantly between subtypes. These results provide guidance for targeted therapy development and support the use of multimodal immune profiling for BTC. For example, GB-specific clinical trials may be considered due to the relative increase in immune-related biomarkers observed in GB and the historically limited success of BTC trials.[Table: see text]

TPS350 Background: Mutations in isocitrate dehydrogenase 1 (mIDH1) are found in approximately 20-30% of patients with intrahepatic cholangiocarcinoma (CCA), and less commonly in glioma, chondrosarcoma, and other gastrointestinal malignancies. Despite documented clinical activity of mIDH1 inhibition in solid tumors, there are no approved targeted therapies for this patient population. LY3410738 is a potent, selective, and covalent inhibitor of mIDH1 R132. LY3410738 is differentiated from prior mIDH1 inhibitors by 1) its unique covalent binding mode, 2) its increased potency, and 3) its unique binding site outside of the dimer interface, which enables activity in the setting of known common second-site IDH1 mutations. Methods: This is an open-label, multicenter, global phase 1 study with oral LY3410738 currently enrolling patients with advanced CCA and other solid tumor types (NCT04521686). A dose escalation cohort will be followed with 4 exploratory expansion cohorts. The primary objective for dose escalation is determination of the maximum tolerated dose (MTD)/recommended phase 2 dose (RP2D). The primary objective for dose expansion is to assess the preliminary anti-tumor activity by ORR of LY3410738 when administered alone or in combination with cisplatin plus gemcitabine. Secondary objectives include evaluating safety and tolerability, pharmacokinetics, pharmacodynamics, progression free survival, and overall survival. Key inclusion criteria include any solid tumor with the presence of mIDH1 R132, ECOG performance status ≤1, and adequate organ function. Any prior treatment including an IDH1 inhibitor is allowed in the dose escalation cohort. Exclusion criteria include presence of active central nervous system metastases, leptomeningeal disease, and active or uncontrolled infection. CCA patients must not have had locoregional therapy within 4 weeks prior to the initial study dose, history of hepatic encephalopathy or refractory ascites, ongoing cholangitis, or mixed hepatocellular-CCA histology. Dose escalation will follow a 3+3 design and will allow patient back-fill to dose levels previously cleared for safety. Each cycle will be 28 days (4 weeks). Once the RP2D is determined, LY3410738 will be evaluated as monotherapy in expansion cohorts 1-3, and in combination with cisplatin plus gemcitabine in expansion cohort 4. Cohort 1 will enroll CCA patients with measurable disease who have received prior chemotherapy. Cohort 2 will enroll patients with advanced solid tumors except CCA who have measurable disease and received standard therapies. Cohort 3 will enroll patients with advanced solid tumors who have non-measurable disease and received standard therapies. Cohort 4 will enroll CCA patients with measurable disease who are treatment naïve for advanced disease. Clinical trial information: NCT04521686.

Abstract Purpose: Patients with metastatic colorectal cancer refractory to chemotherapy have limited treatment options. Ensituximab (NEO-102) is a novel chimeric mAb targeting a variant of MUC5AC with specificity to colorectal cancer. Patients and Methods: Single-arm, phase II trial assessed the efficacy and safety of ensituximab in patients with advanced, refractory cancer who expressed MUC5AC antigen in tumor tissue. Ensituximab was administered intravenously every 2 weeks with 3 mg/kg as recommended phase II dose (RP2D). A minimum sample size of 43 patients was required on the basis of the assumption that ensituximab would improve median overall survival (OS) by 7 months using a one-sided significance level of 10% and 80% power. Written informed consent was obtained from all patients. Results: Sixty-three patients with advanced, refractory colorectal cancer were enrolled and 53 subjects were treated in phase II arm. Median age was 58 years and 46% of the patients were female. Among 57 evaluable patients, median OS was 6.8 months. No responses were observed, and stable disease was achieved in 21% of the patients. The most common treatment-related adverse events (AE) at RP2D included fatigue (38%), anemia (30%), nausea (15%), vomiting (11%), increased bilirubin (9%), constipation (8%), decreased appetite (6%), and diarrhea (6%). Serious AEs at least possibly related to ensituximab occurred in 4 patients and included anemia, nausea, increased bilirubin, and hypoxia. No patients discontinued treatment due to drug-related AEs. Conclusions: Ensituximab was well tolerated and demonstrated modest antitumor activity in patients with heavily pretreated refractory colorectal cancer.