Abou‐Alfa, Ghassan K.

Abstract Background Gastrointestinal (GI) cancer remains a major global health challenge. This study provides updated 2022 estimates of GI cancer incidence and mortality worldwide, along with projections of incident cases and deaths through 2050 to inform cancer control strategies. Methods In this population‐based study, data from the GLOBOCAN 2022 database were used to examine incidence and deaths associated with GI cancer. By using global demographic projections, this study estimated the projected number of incident cases and deaths until the year 2050. Results By 2050, the global burden of GI cancer is projected to reach 9.06 million incident cases (+85%) and 6.42 million deaths (+93%) from 2022. Increases in incidence are projected for both females (+87%) and males (+83%), as are increases in mortality for both females (+97%) and males (+91%). Whereas the Western Pacific region will have the highest absolute burden, with 3.88 million new cases and 2.79 million deaths, the greatest relative increase is expected in Africa, with incidence and deaths rising by 157% and 160%, respectively. As measured by the Human Development Index (HDI), the steepest increases are projected in low (+151% incidence; +152% deaths) and medium (+112% incidence; +114% deaths) HDI countries. Overall, all GI cancer types are projected to increase, led by pancreatic cancer in incidence (+95%) and colorectal cancer in deaths (+103%). Conclusions GI cancer incidence and deaths are expected to nearly double by 2050, with increases across sexes, cancer types, and regions, especially in lower HDI countries.

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 >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.

Immune checkpoint inhibitors (ICIs) have improved cancer prognosis significantly, but their use has been avoided in liver transplant recipients (LTr) due to poorly characterized rejection risk. Data surrounding rejection risk are extremely suboptimal, with highly variable immunosuppression approaches and follow-up, and do not account for the learning curve in managing immunosuppression in the setting of ICI. A standardized institutional clinical practice protocol was developed in 2021 for immunosuppression management to facilitate ICI therapy with prospective close follow-up for immunosuppression levels and allograft function. Of 20 LTr, 12 (60%) were male, 18 (90%) were Caucasian, with a mean age of 54.0 (SD 11.2) years. However, 13/20 had 2 or more failed cancer therapies before ICI. Hepatocellular carcinoma ​(HCC) (N=7), lung (N=3), and melanoma (N=3) were the most frequent. Time from first ICI treatment to death was <30 days (N=5), 30–59 days (N=4), 60–89 days (N=1), and >90 days (N=6). Most deaths were cancer-related, reflecting the late stage of disease. ICI toxicity occurred in 3 LTr; pneumonitis (N=1, 5%), myocarditis (N=1, 5%), and acute cellular rejection (N=1, 5%). Four patients remain alive 178–341 days with stable allograft function and slow reduction in immunosuppression. Three out of 4 patients have a partial cancer response, and 1 with slowed progression of disease. ICI treatment in the immunosuppressed LTr is feasible with careful immunosuppression management and follow-up. Demonstrating a low rejection risk should allow for earlier utilization of these agents to improve cancer prognosis. Optimizing rejection risk with cancer response requires ongoing study.

Background and Aims: In the global phase III HIMALAYA study in unresectable HCC, STRIDE significantly improved overall survival (OS) versus sorafenib; durvalumab was noninferior to sorafenib. Immune checkpoint inhibitor studies have shown an association between the occurrence of immune-mediated adverse events (imAEs) and improved OS. We assessed potential associations between the occurrence of imAEs and OS, and temporal patterns of imAEs, in HIMALAYA. Approach and Results: OS in participants who did and did not experience imAEs and the frequency and timing of imAEs were assessed for STRIDE and durvalumab in the safety analysis set of HIMALAYA. imAEs occurred in 139/388 (35.8%) and 64/388 (16.5%) participants with STRIDE and durvalumab, respectively; most were low grade. OS HRs (95% CI) in participants who experienced imAEs versus those who did not were 0.73 (0.56–0.95) for STRIDE and 1.14 (0.82–1.57) for durvalumab. The 36-month OS rate (95% CI) for STRIDE was 36.2% (28.1–46.7) and 27.7% (22.4–34.2) in participants who did and did not experience imAEs, respectively. The most common imAE category with STRIDE was endocrine events (16.5%). Most imAEs occurred ≤3 months after treatment initiation. Conclusions: Participants who experienced imAEs with STRIDE had a numerical improvement in OS versus those who did not, which was not observed for durvalumab. Long-term OS with STRIDE was observed regardless of imAEs. Most imAEs were low grade, manageable, and occurred in the first 3 months after treatment initiation. Results continue to support the benefits of STRIDE in a diverse population that reflects unresectable HCC globally.

INTRODUCTION: Immune checkpoint inhibitors (ICIs) have become the first-line treatment of unresectable hepatocellular carcinoma (HCC). The prognostic value of immune-related adverse events (irAEs) in these patients remains controversial. We aimed to investigate the association between irAEs and clinical outcomes in patients with HCC treated with ICIs. METHODS: We searched the PubMed, Scopus, Web of Science, and Central Register of Controlled Trials databases for articles published from inception to June 2024, using keywords including ICI, HCC, and irAEs. Statistical analysis was performed with a random effects model. RESULTS: Of 3,028 studies, 24 (4,127 patients) met the criteria for inclusion. Atezolizumab plus bevacizumab was the most common treatment regimen (n = 10 studies). IrAEs were associated with an increased objective response rate (pooled relative ratio: 1.73; 95% confidence interval [CI]: 1.36–2.21, I 2 = 41%), a higher disease control rate (pooled relative ratio: 1.45; 95% CI: 1.21–1.74, I 2 = 74%), and longer progression-free survival (pooled hazard ratio [HR]: 0.66; 95% CI: 0.52–0.84, I 2 = 71%). There was a trend toward longer overall survival for patients with irAEs compared with those without (pooled HR: 0.84; 95% CI: 0.63–1.12, I 2 = 73%). Subgroup analysis indicated a survival benefit for patients with grade 1–2 irAEs (pooled HR: 0.50; 95% CI: 0.36–0.67, I 2 = 0%) and for those with endocrine irAEs (pooled HR: 0.63; 95% CI: 0.48–0.83, I 2 = 12%). DISCUSSION: The development of irAEs is associated with favorable clinical outcomes in HCC, including improved progression-free survival and higher objective response rate. Overall survival benefit was noted in patients with mild irAEs but not those with severe irAEs.

Abstract Background: Ivosidenib (IVO) is a first-in-class oral inhibitor of the IDH1 mutant (mIDH) enzyme. In the ClarIDHy phase 3 study of previously treated patients with mIDH cholangiocarcinoma (CCA), IVO treatment led to improved progression-free survival (PFS) and overall survival (OS) vs placebo (median PFS: 2.7 vs. 1.4 months and OS 10.3 vs. 5.1 months, when adjusted for the 70% crossover rate; HR, 0.49 [95% CI, 0.34-0.70]; 1-sided P&lt;0.001. Here, we studied the dynamics of mutations emerging after 6 months of IVO treatment using ctDNA analyses. Methods: Prior to enrollment, all subjects in ClarIDHy had IDH1 R132 mutations confirmed by a central NGS panel utilizing tumor biopsy tissue. Since post-progression tissue samples were unavailable, discovery of emerging mutations was limited to plasma ctDNA assessments. To explore molecular changes associated with acquired resistance, an analysis was performed on 18 subjects treated with IVO for ≥6 months (4 partial response; 12 stable disease, 2 NA) using matched baseline and end of treatment (EOT) samples (PGDx elioTM plasma complete, 521 gene panel). A subset of the oncogenic alterations identified were selected for confirmation by ddPCR analysis in ctDNA samples collected longitudinally. Longitudinal plasma 2HG levels were also evaluated. Results: This analysis identified several EOT mutations not present at baseline. The most common mutations were in the MAPK pathway, including activating KRAS, NRAS, and MAP2K1 mutations and loss-of-function NF1 mutations (6/18 patients, 33%). In 2/6 patients, multiple MAPK pathway mutations were detected. There was a range of variant allele frequencies (VAFs) of RAS alterations, including some that had comparable levels to the truncal mIDH, suggesting that MAPK activation may have made a major contribution to the burden of resistant disease. ddPCR analyses from longitudinal plasma samples from selected cases confirmed these findings. In addition, 2 patients had mutations affecting transcription/epigenetics (WT1 and KMT2C). Finally, only 1 patient had acquired mutations in IDH genes (IDH2-R172K and IDH1-G131V). The WT1, KMT2C, and IDH variants had a low VAF. Accordingly, EOT plasma 2HG levels were reduced vs pre-treatment levels in the patient with secondary mIDH, indicating a limited role in the overall emergence of resistance. Conclusion: Analyses of paired baseline/EOT samples suggest that multiple acquired mutations could contribute to IVO resistance, with oncogenic MAPK pathway alterations being the most common. Consistent with previous clinical studies conducted in AML, IDH1 second site mutations and isotype switching to IDH2, rarely emerge during IVO treatment. The lack of detectable mutations in the majority of patients could reflect the sensitivity of the NGS assay or a role for non-genetic mechanisms of resistance. Citation Format: Hatice Duygu Saatcioglu, Haley Ellis, Jinkai Wan, Sam Lubner, Milind Javle, Ghassan K. Abou-Alfa, James M. Cleary, Robin Kate Kelley, Mitesh J. Borad, Teresa Macarulla, Do Youn Oh, Camelia Gliser, Susan Pandya, Sung Chloe, Nabeel Bardeesy, Adriana Tron. Circulating tumor DNA analysis demonstrates newly emerging alterations in previously treated IDH1 mutated cholangiocarcinoma patients enrolled in the ClarIDHy study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4648.

Background and Aims: Immunotherapy has emerged as an effective treatment for advanced HCC. We aimed to investigate the real-world effectiveness of immunotherapy compared to lenvatinib in HCC. Approach and Results: From the TriNetX database, we used a target trial emulation framework and identified patients with HCC who received first-line treatment with immunotherapy (atezolizumab/bevacizumab or tremelimumab/durvalumab) or lenvatinib between or between August 2018 and December 2023. OS was compared using Kaplan-Meier analysis and Cox proportional hazards regression. After propensity score matching, 1203 patients were included in each group. Immunotherapy was associated with improved OS versus lenvatinib (median survival: 545 vs. 425 d; HR: 0.86, 95% CI: 0.76–0.97). Regarding treatment type, atezolizumab plus bevacizumab showed improved survival compared to lenvatinib (n=1070 in each group; HR: 0.87, 95% CI: 0.77–0.99), while the point estimate favored durvalumab plus tremelimumab versus lenvatinib (HR: 0.81, 95% CI: 0.59–1.12), though this difference was not statistically significant, likely due to small sample size. Regarding etiology, immunotherapy had improved OS compared to lenvatinib in viral hepatitis (n=510 in each group; HR: 0.74, 95% CI: 0.61–0.89) and alcohol-associated liver disease (n=190 in each group; HR: 0.65, 95% CI: 0.49–0.87), but not in metabolic dysfunction–associated steatotic liver diseases (n=156 in each group; HR: 0.96, 95% CI: 0.70–1.31). Conclusions: In this real-world analysis, immunotherapy was associated with improved OS compared to lenvatinib in advanced HCC, with consistent benefit across most subgroups. These findings support the use of immunotherapy as a first-line treatment for advanced HCC.

566 Background: Immune checkpoint inhibitors (ICIs) have become the preferred treatment for unresectable hepatocellular carcinoma (HCC). Conflicting data exist regarding the prognostic value of immune-related adverse events (irAEs) in these patients. We aimed to explore potential the association between irAEs and prognosis in HCC patients treated with ICIs. Methods: We searched PubMed, Scopus, Web of Science, and CENTRAL databases for articles published from inception to June 2024 using keywords including ICI, HCC, and irAEs. Two reviewers independently screened studies for eligibility and relevant data. A random effects model was used for statistical analysis, and subgroup analysis was performed by the grade of irAEs. Results: Of 3,028 studies, 25 (n=4,116 patients) met criteria for inclusion. Atezolizumab plus bevacizumab was the most common treatment regimen (n=10 studies). About half (49.5%) of patients experienced irAEs. irAEs were associated with increased objective response rate (ORR) (pooled OR: 1.72; 95% CI: 1.36 – 2.19, I 2 =39%), higher complete response rate (pooled OR: 1.45; 95% CI: 1.21-1.74, I 2 =74%), and longer progression-free survival (PFS) (pooled HR: 0.66; 95% CI: 0.52-0.84, I 2 =71%). Although irAEs were associated with longer overall survival, this difference was not statistically significant (pooled HR: 0.83; 95% CI: 0.62 – 1.11, I 2 =73%). Subgroup analysis showed a survival benefit for patients with grade 1-2 irAEs (pooled HR: 0.50; 95% CI: 0.36-0.67, I 2 =0%) but not for those with grade 3-4 irAEs (pooled HR: 0.95; 95% CI: 0.24-3.72, I 2 =84%). Conclusions: The development of irAEs is associated with a favorable prognosis in HCC, including improved PFS and higher ORR. A survival benefit was noted in patients with mild irAEs, but not in those with severe irAEs. Future studies are needed to determine if a differential survival benefit relates to the continuation vs. discontinuation of ICI therapy.

TPS4196 Background: Advanced BTC patients have poor prognosis. Up to 40% of BTCs have KRAS mutations and are associated with worse overall survival (OS). With a median OS of 7.7 months in KRAS wild-type compared to 1.7 months in KRAS mutated disease, these alterations are independent poor prognostic factors in BTC. Gemcitabine and cisplatin (GC) with or without immunotherapy are often used as 1st-line therapies. However, there is a lack of data on best 2nd-line regimens. mFOLFOX6 (5-fluorouracil [5-FU], leucovorin [LV], oxaliplatin) or liposomal irinotecan+5-FU+LV are options when no biomarkers are found (e.g., MSI-H, BRAFV600E, FGFR-fusions, IDH1-mutation, HER2-overexpression). Prior studies do not demonstrate benefit with MEK inhibitors (MEKi), but none of the studies had biomarker selection. Pre-clinical studies in BTC cell lines suggest synergy between MEKi and 5-FU. Thymidylate synthase (TS )levels induced by 5-FU are downregulated by addition of binimetinib. Early clinical studies show safety and tolerance of this combination. In this study, we will evaluate if the combination of mFOLFOX6+binimetinib improves OS for patients with BTC and MAPK mutations compared to mFOLFOX6 alone in 2nd-line therapy. Methods: EAY191-A6 is a treatment study arm of the NCI ComboMATCH master registration trial EAY191. The A6 trial has a randomized phase II design, enrolling a maximum of 66 patients. Patients with any MAPK pathway mutations except those with available therapies will be eligible. Patient must first enroll to the EAY191 master trial. Local molecular results may be used for enrollment. Submission of tissue at baseline is mandatory. Eligible patients will be randomized 1:1 to mFOLFOX6 vs mFOLFOX6 + binimetinib (45 mg oral twice a day every 14 days). Stratification factors include location and stage of disease. Primary efficacy analysis will compare OS in the intent-to-treat population. If the observed hazard ratio (HR) of experimental arm vs standard of care is < 0.545 (corresponding to an observed increase in OS by 5 months or longer), experimental treatment will be considered superior. An interim futility analysis at 50% of expected events will be conducted. If the observed HR is ≥ 1, experimental treatment will not be considered superior, and accrual maybe suspended. Secondary endpoints include progression-free survival, objective response rate, duration of response, disease control rate and toxicity of treatments. Exploratory objectives include prognostic modeling, correlations of genomic alterations with response or resistance and use of machine learning for outcome prediction. This study is active and open to accrual. Clinical trial information: NCT05564403 .