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Abstract Background The increasing reliance on accelerated approvals and surrogate endpoints for Food and Drug Administration (FDA) approvals of gastrointestinal (GI) cancer therapies raises concerns about their clinical benefit and long-term patient outcomes. The shift toward single-arm trials in regulatory decisions further complicates treatment evaluation. Material and Methods This retrospective observational study evaluated all FDA approvals for GI cancer therapies from January 2006 through January 2025. Data were extracted from FDA archives, ClinicalTrials.gov, and PubMed. Approvals were categorized by regulatory pathway (accelerated vs regular), trial design (single-arm vs randomized), and primary endpoint (surrogate vs overall survival [OS]). Clinical benefit was assessed based on OS improvement and the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS). The primary outcome was the proportion of approvals based on surrogate versus OS endpoints. Secondary outcomes included use of single-arm designs, frequency of accelerated approvals, OS gain, and the proportion meeting ESMO-MCBS substantial benefit (score ≥ 4). Results The FDA granted 60 GI cancer drug approvals from 67 trials. Approvals rose from 15 (25%) in 2006-2014 to 45 (75%) in 2015-2025. Single-arm trials increased to 24%, and surrogate endpoints were used in 41.8% (ORR 20.9%, PFS 19.4%). Median OS improvement was 2.1 months (IQR: 1.6-2.65). Only 24.3% of trials met ESMO-MCBS substantial benefit. Of 15 accelerated approvals, 66.7% remained pending, 13.3% received full approval, and 20% were withdrawn. Conclusion Expedited approvals have improved drug access in GI oncology, but modest benefits highlight the need to balance speed with outcomes that truly matter to patients.

Abstract Background This phase 1 study aimed to determine the maximum tolerated dose (MTD) and evaluate the safety and preliminary efficacy of rucaparib (RUB), a poly(adenosine diphosphate ribose) polymerase (PARP) inhibitor, combined with liposomal irinotecan (nal‐IRI) and 5‐fluorouracil (5‐FU) in metastatic gastrointestinal (GI) cancers. RUB targets DNA repair pathways, showing efficacy in tumors with homologous recombination deficiency, such as BRCA mutations. Preclinical data suggest synergy with irinotecan, but overlapping toxicities pose challenges. Methods Eighteen patients with metastatic GI cancers, who previously progressed on at least one systemic therapy, were enrolled. A novel sequential dosing regimen, informed by nal‐IRI pharmacokinetic analysis, was used. Twelve patients were evaluable for dose‐limiting toxicity (DLT) and 12 for response per Response Evaluation Criteria in Solid Tumors v1.1 criteria. Results The MTD was established as RUB 600 mg twice daily, nal‐IRI 50 mg/m 2 , and 5‐FU 2400 mg/m 2 over 46 hours. The objective response rate (ORR) was 33% (4 of 12), and the disease control rate (DCR) was 75% (9 of 12). Common grade 3 adverse events included diarrhea (33%) and neutropenia (25%), with no grade 4/5 events. Responses were notable in patients with somatic ATM and BRCA mutations, especially those with prior platinum exposure. No DLTs occurred at the recommended phase 2 dose. Conclusions This optimized dosing schedule successfully established the MTD for RUB with nal‐IRI and 5‐FU, overcoming prior challenges with PARP inhibitor and irinotecan combinations. The promising ORR and DCR support further evaluation of this regimen in advanced GI malignancies.

PURPOSE Neoadjuvant immune checkpoint inhibitors (nICIs) have demonstrated high response rates in deficient mismatch repair/microsatellite instability–high (dMMR/MSI-H) gastroesophageal adenocarcinoma (GEA). The NEONIPIGA and INFINITY trials demonstrated high rates of pathologic complete response (pCR) in this patient population. Furthermore, the INFINITY trial explored the feasibility of managing these patients nonoperatively, demonstrating promising results. This study aimed to evaluate clinical outcomes of nICIs in resectable dMMR/MSI-H GEA, with a focus on the feasibility of nonoperative management (NOM). MATERIALS AND METHODS This retrospective cohort study included patients with resectable dMMR/MSI-H GEA and treated with nICIs ± surgery at the Mayo Clinic. Patients were identified from institutional records, and clinical data were retrospectively reviewed. Primary outcomes were clinical complete response (cCR) and pCR. Secondary outcomes included event-free survival (EFS), radiologic complete response (rCR), and immune-related adverse events (irAEs). RESULTS A total of 26 patients treated between April 1, 2017, and July 30, 2025, were identified. Nine patients (34.6%) underwent surgery, of whom six (66.7%) achieved pCR. Seventeen patients (65.4%) pursued NOM, with 10 (71.4%) of 14 evaluable patients achieving cCR and 14 (82.4%) of 17 evaluable achieving rCR. One patient who initially achieved cCR had a local recurrence on surveillance endoscopy and underwent salvage endoscopic resection. At a median follow-up of 19.3 months, 15 (88.2%) of 17 patients in the NOM cohort were alive and metastasis-free, with EFS rates of 87.3% at 12 and 24 months for all patients. irAEs occurred in nine patients (34.6%), with no grade ≥3 toxicities. CONCLUSION In this retrospective cohort study, nICIs led to high cCR and pCR rates in resectable dMMR/MSI-H GEA, supporting the use of immune checkpoint inhibitors in this setting and the feasibility of NOM in select patients.

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 < .001); median TTD(m): 6.1, 2.3, 3.0, 1.3 (P < .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.

Background/Objectives: Results from a well-designed trial provide evidence to support approval of truly effective treatments or discontinuation of ineffective treatments. However, the information available at the time of trial design may be limited which may lead to underpowered trials. This work aims to evaluate the impact of design assumption misspecifications on the statistical power of randomized trials with survival outcomes. Methods: The impact of the design assumption misspecifications on statistical power of four different statistical methods was investigated in a simulation study. The methods include the log-rank test, MaxCombo test, the test of difference in survival probability, and test of difference in restricted mean survival time (RMST). The deviations considered include the survival rate in the control arm, the expected treatment effect in terms of magnitude and pattern, accrual rate, and drop-out rate. Results: Deviations in the control arm’s survival distribution have no impact on the power of the log-rank and MaxCombo tests but it affects the trial duration since trials designed with these tests require the total number of events to be met before the final analysis can be conducted. Misspecified treatment effect has similar effect on the statistical power of all four methods. When the proportional hazards assumption is misspecified, the RMST is more robust with a larger early treatment effect, while the survival probability and the MaxCombo tests are more robust with a larger late treatment effect and crossing hazards. Conclusions: Selecting the appropriate statistical tests to design a trial depends on the goal of the trial, the mechanism of action of the experimental treatment, the survival quantity of clinical interest, and the pattern of the expected treatment effect. The final design should be based on assumptions that are as accurate as possible, and the potential impacts of deviations from these assumptions on the trial’s statistical power should be carefully considered.

Abstract Background FGFR alterations are known to be driver alterations in several tumor types. We aimed to assess the efficacy of pemigatinib, an oral FGFR1-3 inhibitor, in patients with metastatic or unresectable colorectal cancer whose tumors harbored FGF/FGFR alterations. Patients and Methods The ACCRU-GI-1701 is a single-arm phase II trial which enrolled patients with previously treated FGF/FGFR-altered metastatic colorectal cancer to receive oral pemigatinib daily in 21-day cycles. The primary endpoint is objective response. Secondary endpoints include clinical benefit, progression-free survival, overall survival, quality of life, and adverse events (AEs). This trial was registered with ClinicalTrials.gov (NCT04096417). Results Of the 14 patients included in the interim analysis, the objective response rate as well as clinical benefit rate were 0%. Given these results, the trial closed to enrollment after stage one due to futility. A total of 42.9% of patients had at least one grade 3 or higher AE, the most common being anemia and fatigue. Conclusion Pemigatinib monotherapy did not lead to objective responses in patients with chemorefractory metastatic colorectal cancer harboring FGF/FGFR alterations, although it was overall relatively well tolerated with no new safety signals. Notably, 93% (n = 13) of patients had only FGF/FGFR mutations and amplifications; one patient had an FGFR3-WHSC1 fusion at a low cfDNA percentage (0.02%).

LBA1 Background: Standard adjuvant chemotherapy of stage III colon cancer consists of a fluoropyrimidine plus oxaliplatin. In patients (pts) with stage III colon cancer and deficient mismatch repair (dMMR), the benefit of an immune checkpoint inhibitor combined with adjuvant chemotherapy is unknown. The phase III ATOMIC trial (NCT02912559) was conducted to determine whether atezolizumab (atezo), an anti-PD-L1 antibody, can improve pt outcomes when added to adjuvant 5-fluorouracil, leucovorin plus oxaliplatin (mFOLFOX6) in pts with stage III dMMR tumors. Methods: We conducted an NCI-sponsored, multicenter and randomized phase III trial in pts with surgically resected stage III dMMR colon adenocarcinoma (any T, N 1,2 M 0 ). Pts, age > 12 years (yr), were accrued at NCTN sites and the German AIO. Tumor dMMR was determined by local immunohistochemistry and centrally verified. Pts were randomized 1:1 to mFOLFOX6 plus atezo (840 mg IV q2 weeks) for 12 cycles (6 months)[mo] followed by atezo monotherapy for 13 cycles (12 mo total) versus mFOLFOX6 alone for 12 cycles. Randomization stratification factors were N-stage (N 1 /N 1c vs N 2 ), T-stage (T 1 -T 3 vs T 4 ) and site (proximal vs distal). The primary endpoint was disease-free survival (DFS); secondary endpoints were overall survival and adverse event (AE) profile (CTCAE, PRO-CTCAE). Primary efficacy analysis was done in the intent-to-treat population; DFS was compared by arm (stratified log-rank test). Hazard ratio (HR) and 95% confidence interval (CI) were calculated using a stratified Cox model; 3-yr DFS was determined by Kaplan-Meier method. Among 700 pts., 165 DFS events with two interim analyses (50% , 75% of events) yielded 90% power to detect HR 0.6 (3-yr DFS 75% vs. 84.2%) assuming exponential survival and 1-sided alpha (0.025). Results: From 9/2017 to 1/2023, 712 pts were randomized (1 pediatric) to either atezo plus mFOLFOX6 (n= 355; atezo arm) or mFOLFOX6 (n= 357). Median pt age was 64 yr. 55.1% were female. Among tumors, 83.8% were proximal, 46.1% were clinical low risk (T 1-3 N 1 ) and 53.9% high risk (T 4 and/or N 2 ). At the second interim analysis, median pt follow-up was 37.2 mo (interquartile range, 24.2 to 55.5) and 124 DFS events were observed. Three-year DFS was 86.4 % (95% CI, 81.8 to 89.9) in the atezo arm and 76.6 % (95% CI, 71.3 to 81.0) in the mFOLFOX6 arm (HR, 0.50; 95% CI, 0.35 to 0.72). Stratified log-rank p-value was <0.0001, crossing the pre-specified efficacy boundary of 0.009. Efficacy for the atezo arm was consistent across subgroups, including pts >70 yr and low- and high-risk groups. Treatment-related > grade 3 AEs occurred in 71.7 % of pts in the atezo arm vs 62.1 % in the mFOLFOX6 arm. Conclusion: The addition of atezolizumab to mFOLFOX6 significantly improved DFS and should be considered the new adjuvant standard of care for patients with dMMR stage III colon cancer. Support: U10CA180821, U10CA180882, U24CA196171; Genentech, a member of the Roche group; https://acknowledgments.alliancefound.org. Clinical trial information: NCT02912559 .

e23317 Background: mCRC poses significant challenges, particularly in patients (pts) who progress after multiple lines of therapy. Limited effective treatment options are available in the advanced chemotherapy-refractory setting. The FRESCO-2 trial demonstrated that Fruq, a selective VEGFR inhibitor, provides meaningful overall survival (OS) benefit in pts with refractory mCRC. However, there is limited real-world evidence regarding Fruq's efficacy in patients treated after approved third-line therapies. Methods: This retrospective, multi-site cohort study evaluated outcomes in 33 mCRC pts who received Fruq following treatment with Rego and/or TAS-102 with or without bevacizumab. Patients were stratified into two groups: Fruq as a second late-line therapy, after either Rego or TAS-102, (27 patients) and as a third late-line therapy, after both Rego and TAS-102, (6 patients). Overall survival (OS) was calculated from Fruq initiation to death, while time to treatment discontinuation (TTD) was defined as the duration from Fruq initiation to cessation for any reason, including death. Survival analysis was performed using the Kaplan-Meier method to estimate median survival, and the comparison between groups were done using the log-rank test. Results: Among the 33 pts, the median age was 58 years (range: 35–84), with 57.6% being male. Hepatic metastases were present in 78.8%, and 60.6% had left-sided primary tumors. RAS mutations were observed in 63.6%, and 97% were BRAF wild-type. Median OS was significantly longer in pts who received Fruq as a second late-line therapy (7.2 months) compared to those receiving it as a third late-line therapy (4.0 months) (p = 0.039). Median TTD was similar between groups (2.4 vs. 2.8 months, p = 0.916). Conclusions: This real-world analysis highlights the clinical benefit of Fruquintinib in mCRC patients following treatment with Regorafenib and/or TAS-102. The data suggest flexibility in treatment choices, with Fruquintinib showing improved OS when used earlier in the treatment sequence. These findings underscore the importance of exploring optimal sequencing strategies and evaluating Fruquintinib as a potential option before other approved agents in the refractory setting. Clinical outcomes with fruquintinib as second vs. third late-line therapy. Fruq as Second Late-Line Fruq as Third Late-Line p-value Median OS 7.2 months 4 months 0.039 Median TTD 2.4 months 2.8 months 0.916 OS: Overall Survival; TTD: Time to Treatment discontinuation.

4085 Background: Cholangiocarcinoma (CC) is a rare disease with an increasing incidence among younger adults, which is poorly understood. Genomic profiling of tumors is both prognostic and predictive of benefit for targeted therapies. We investigated if there are clinical and molecular differences between younger vs older patients with CC. Methods: We collected TEMPUS genetic data via retrospective chart review from tumors in young vs old patients seen at our institution, defined as ≤50 vs > 50 years of age at time of diagnosis. We included patients diagnosed with CC between January 2008 and July 2024 with available clinical follow up and TEMPUS genetic sequencing data. We collected mutation data on the following actionable genes: FGFR2, IDH1/2, BRCA1, BRCA2, BRAF, ATM, ERBB2/3, and KRAS. Patient characteristics and gene expression variables were compared using Chi-square, Fisher’s exact and Wilcoxon rank-sum tests. Kaplan-Meier, log rank tests and a multivariable Cox model were used for survival analysis. This study was IRB exempt. Results: We included 410 patients, 84 in the young group with median age at diagnosis of 40.8 years, and 326 in the old group with median age 68.5 years. 91.5% of patients were white. There was no difference in BMI between groups, however the older group had higher rates of hypertension (15.5% vs 57.7%), hyperlipidemia (6.0% vs 49.7%), cardiovascular disease (1.2% vs 20.6%), and type 2 diabetes (6.0% vs 21.5%), (all p < 0.01). Primary sclerosing cholangitis was more common in the young group (26.2% vs 4.3%, p < 0.01). ECOG status of 0 at first treatment was seen in 65.3% of young vs 52.5% of old patients (p = 0.02). FGFR2 alterations were more common in the young group (17.9% vs 8.0%, p < 0.01), while ATM mutations were more common in old vs young (5.5% vs 0%, p = 0.03). There was no age difference seen for the other genetic alterations. Mean tumor mutational burden was higher in the old group (4.1 vs 3.8 mut/mb, p = 0.01). MSI-high was found in 2% of cases with no difference between groups. There was no significant difference in overall survival between age groups. There was a numeric difference in overall survival in stage IV patients, though not statistically significant (17.8 months vs. 16.3 months, p = 0.08). In a multivariable Cox analysis, female sex, earlier stage at diagnosis and clinical trial enrollment were associated with favorable prognostics. Conclusions: Our data highlight relatively low rates of comorbidities associated with metabolic dysfunction in younger adults with CC, suggesting alternative factors are likely to explain the increasing incidence of early-onset disease. FGRFR2 is a more common pathogenic alteration among the young and could inform targeted therapies. Younger patients with CC may not have improved survival outcomes compared to their older counterparts. This underscores the aggressive nature of CC and the need for more effective therapies to improve outcomes.

4020 Background: In previously treated patients (pts) with advanced extra-pancreatic NET (epNET) or pancreatic NET (pNET), cabozantinib (cabo) demonstrated improved progression-free survival compared to placebo (pbo) in the CABINET trial (NCT03375320). Here we present HRQOL data from CABINET. Methods: Pts with previously treated unresectable, locally advanced or metastatic epNET or pNET were randomized (2:1) in separate cohorts to receive cabo 60 mg daily vs pbo. HRQOL was an exploratory endpoint measured using the EORTC QLQ-C30, QLQ-GI.NET21, Patient Global Impression of Change (PGIC), and PRO-CTCAE questionnaires. Optional participation was by paper surveys at baseline and every 12 weeks (wks) until disease progression or new anticancer therapy. Mean changes from baseline were compared between treatment arms at wk12 using general linear mixed models. Minimally important within-arm improvements and between-arm differences were defined as 8 points on the C30 Global Health Status (GHS)/QOL Scale. PGIC was dichotomized as improved vs unchanged/worsened and compared using Chi-squared tests. Rates of pt-reported adverse events (AEs) by PRO-CTCAE were baseline-adjusted and compared using Fisher’s exact tests. Results: 172 pts (113 cabo, 59 pbo) with epNET and 81 pts (53 cabo, 28 pbo) with pNET consented for survey participation. Pts completed 524 (82%) of 640 expected surveys across baseline, wk12, and wk24. For epNET, C30 GHS/QOL was significantly improved at wk12 in pts receiving cabo (mean change 9.5, standard error (SE) 2.2, p < 0.001) but not pbo (mean change 0.2, SE 3.1, p = 0.95) resulting in significantly different mean changes from baseline between arms (p = 0.02). For pNET, C30 QHS/QOL was significantly improved at wk12 in pts receiving cabo (mean change 8.0, SE 3.0, p = 0.008) but not pbo (mean change 6.8, SE 4.4, p = 0.12); mean changes from baseline did not statistically differ between arms (p = 0.82). No significant differences in mean changes from baseline at wk12 in C30 Physical, Role, Emotional, Cognitive and Social Function were observed between arms in the epNET or pNET cohorts. In both cohorts at wk12, pts on cabo reported improved overall status as measured by PGIC more often than those on pbo (epNET: 38% vs 19%, p = 0.04; pNET: 57% vs 18%, p = 0.006). Rates of pt-reported AEs were statistically significantly higher in cabo for diarrhea (68% vs 53%), hand-foot syndrome (57% vs 26%), mouth or throat sores (47% vs 27%), and dysgeusia (67% vs 37%) [all p < 0.05]. GI.NET21 data will be presented. Conclusions: Although cabo is associated with pt-reported AEs consistent with its known safety profile, global HRQOL was maintained. A higher proportion of patients receiving cabo reported improved overall status. Results support cabo as a treatment option for pts with previously treated advanced NET that preserves patient HRQOL. Clinical trial information: NCT03375320 .