4122 Background: BTCs are rare and aggressive malignancies. The first-line standard of care regimen for advanced BTC (aBTC) is gemcitabine (GEM), cisplatin, and an immune checkpoint inhibitor. Although FOLFOX is a preferred second-line treatment, it is limited by neuropathy. Nal-IRI contains IRI free base in liposome nanoparticles, which shelter IRI from conversion to its active metabolite (SN-38) and increase intratumoral SN-38 compared with IRI alone. The NAPOLI-1 trial of FU/LV/nal-IRI vs. FU/LV in second-line advanced pancreatic adenocarcinoma showed an overall survival (OS) benefit. The NIFTY trial (South Korea) demonstrated median OS (mOS) benefit of FU/LV/nal-IRI over FU/LV in a second-line aBTC population (8.6 vs. 5.3 months [mo], HR 0.68, 95% CI 0.48-0.95); however, the NALIRICC trial (Germany) did not (6.9 vs. 8.2 mo, HR 1.08, 95% CI 0.68-1.72). We sought to characterize second-line FU/LV/nal-IRI efficacy in US patients (pts) with second-line aBTC. Methods: This was a single-arm, open-label, multicenter phase II study of pts with aBTC previously treated with GEM/platinum chemotherapy. Pts received nal-IRI 70 mg/m 2 IV over 90 minutes, LV 400 mg/m 2 IV over 30 minutes every 14 days, and FU 2400 mg/m 2 IV over 46 hours every 14 days. The primary objective was to determine progression-free survival rate at 4 mo (PFS 4mo ) using RECIST v. 1.1 criteria. Median PFS reported for pts receiving second-line 5-FU doublet chemotherapy was 3 mo with a PFS of 30%. FU/LV/nal-IRI was of interest if it could increase the PFS 4mo to 50% or higher. Using a one-sided α of 0.05 and 80% power, 17 of 39 evaluable pts had to be progression-free at 4 mo to detect a difference in PFS 4mo between 30% and 50%. Results: Forty-eight pts were enrolled: median age 64.5 years; 69% women; 27% gallbladder primary; 54% intra- and 19% extrahepatic. Ten pts came off study due to toxicity without disease progression before 4 mo on study and were replaced to evaluate the PFS 4mo endpoint. Of 38 evaluable pts, 18 pts (PFS 4mo 47%) were alive and progression-free at 4 mo, meeting the primary endpoint. With a median follow-up of 7.1 mo, median time to disease progression or study discontinuation due to toxicity for all pts was 2.3 mo (95% CI 1.8-4.6, PFS 4mo 38%), and for pts evaluable for the primary endpoint, median PFS was 3.5 mo (95% CI 1.8-5.5). Five pts (10%) had PFS beyond 12 mo. mOS for all pts was 7.9 mo (95% CI 5.7-11.7). Of 41 evaluable pts, the response rate was 2% (1 PR), and the disease control rate was 54%. Adverse events (AEs) were consistent with known toxicities from the FU/LV/nal-IRI regimen. Conclusions: FU/LV/nal-IRI is an effective second-line regimen for aBTC in US pts. There was significant early toxicity as 21% of pts came off study due to AEs before 4 mo. Correlative studies, including longitudinal analyses of circulating tumor DNA using banked blood specimens, are planned (NCT04005339). Clinical trial information: NCT04005339 .

162 Background: In preclinical studies, the tryptophan-metabolizing enzyme, Indoleamine 2, 3-dioxygenase 1 (IDO1), promotes resistance to radiation in colorectal cancer, and IDO1 inhibition with epacadostat improves tumor radiosensitivity. In a phase 1 trial, patients (pts) with locally advanced rectal cancer (LARC, n=17) were treated with epacadostat in combination with short course radiotherapy (SCRT) and CAPOX which was well-tolerated, and the recommended phase 2 dose (RP2D) of epacadostat was 400mg BID. Here we report efficacy and safety from the NCI-supported phase 2 (NCT03516708) multicenter, open-label trial (treatment cohort). Methods: Pts were treated with standard of care (SOC) SCRT, then SOC neoadjuvant chemotherapy (NAC) followed by SOC surgical resection or non-operative management (NOM). Epacadostat (400 mg BID) started with SCRT and continued until starting NAC (a minimum of 21 days). Eight pts were enrolled prior to discontinuation of epacadostat by Incyte in February/March 2025. The primary endpoint is Neoadjuvant Rectal (NAR) score. In patients who underwent NOM, we calculated MRI-based tumor regression grade (MR-TRG). Secondary endpoints are pathologic complete response (pCR) rate, complete clinical response (cCR) rate, and progression free survival (PFS). Results: Table 1 summarizes baseline characteristics and endpoints (primary and secondary). NOM was pursued in 7/8 (87.5%) pts, surgical resection was performed on 1/8 (12.5%). At median follow-up of 12 months, local tumor regrowth occurred in 1 pt initially treated with NOM (after tumor regrowth, he underwent salvage surgery and is currently on surveillance). Treatment with epacadostat was interrupted in 2/8 (25%) patients due to grade 3 maculopapular skin rash. Most frequent treatment-emergent adverse events (TEAEs) regardless of causality (all grades (G)/G3-4) were bloating (75%/0%), increased ALT (62.5%/0%), increased AST (50%/0%), nausea (50%/0%), and constipation (50%/0%). Grade 3 diarrhea and grade 3 non-cardiac chest pain occurred in 1 patient each (both unrelated to epacadostat). Conclusions: Epacadostat demonstrates promising efficacy and manageable safety in patients with LARC. The biomarker cohort and correlative studies are ongoing. Clinical trial information: NCT03516708 . Baseline characteristics and endpoints. Patient Age Sex Ethnicity Stage Surgery/NOM NAR MR-TRG cCR/pCR Recurrence 1 52 M Caucasian T3N1 NOM NA 2 Y/NA No 2 45 M Caucasian T3N1 NOM NA 3 Y/NA Local tumor regrowth 3 48 M Caucasian T3N2 NOM NA 3 Y/NA No 4 61 M Caucasian T4N2 NOM NA 3 Y/NA No 5 57 M Caucasian T3N0 NOM NA 1 Y/NA No 6 60 F Caucasian T3N1 Surgery 15 3 N/ypT3N0 No 7 67 M Caucasian T4N0 NOM NA 3 Y/NA No 8 51 M Caucasian T4N2 NOM NA P NA No

163 Background: Being physically inactive is an independent predictor of poor outcomes in patients with stage III colon cancer. Whether physical activity can mitigate the oncologic risk of postoperative MRD is unknown. Methods: We concluded a post hoc analysis of a phase III trial evaluating celecoxib vs. placebo and 3 vs. 6 months of adjuvant chemotherapy in patients with resected stage III colon cancer. Self-reported physical activity was assessed in standardized measures of metabolic equivalent hours per week (MET-h/wk) at 2 timepoints: 1) midway through and 2) 6 months after completing adjuvant chemotherapy, modeled as a time-weighted average. MRD was determined via a clinically validated, tumor-informed circulating tumor DNA (ctDNA) assay (Signatera, Natera, Inc.). Disease-free survival (DFS) and overall survival (OS) were estimated using flexible parametric survival models. Results: Among 763 patients (median follow-up 6.0 years), 24% were highly active (≥18 MET-h/wk) and 32% were inactive (<3 MET-h/wk); 18% were ctDNA positive. Adjusting for covariates, DFS improved in patients who were ctDNA negative and moderately active (Ref: inactive; 3-17.9 MET-h/wk; HR=0.62, 95% CI [0.40-0.97]) or highly active (HR = 0.53 [0.30-0.94]). No benefit was seen among patients who were ctDNA positive (Ref: inactive; moderately active: HR = 1.20 [0.75-1.92]; highly active: HR=0.83 [0.45-1.54]). The interaction was not significant (Pint=0.269). Physical activity did not impact OS regardless of ctDNA status. The interaction of physical activity and adjuvant celecoxib use is shown in Table. Conclusions: Among patients who were ctDNA negative, physical activity was associated with improved DFS, and may demonstrate increased survival benefit alongside adjuvant celecoxib. The additive effects of both interventions were inconclusive among those who were ctDNA positive. Support: U10CA180821, U10CA180882, U24CA196171; https://acknowledgments.alliancefound.org; Natera, Pfizer; NCT01150045. Disease-free survival by physical activity level and celecoxib use, stratified by ctDNA status. 3-yr event # at risk Adjusted HR (95% CI) P-value Pint ctDNA Negative 0.258 Inactive + placebo 23 182 Ref Active + placebo 17 132 0.74 (0.43-1.28) 0.283 Inactive + celecoxib 23 167 0.92 (0.57-1.48) 0.720 Active + celecoxib 10 146 0.40 (0.22-0.79) 0.007 ctDNA Positive 0.221 Inactive + placebo 26 33 Ref Active + placebo 15 20 0.96 (0.50-1.84) 0.903 Inactive + celecoxib 34 54 0.62 (0.37-1.05) 0.076 Active + celecoxib 14 29 0.34 (0.18-0.64) 0.001 ctDNA, circulating tumor DNA; HR, hazard ratio; CI, confidence interval. Active = ≥9 MET-h/week, inactive = <9 MET-h/week. Celecoxib use defined by assignment in CALGB/SWOG 80702. Models adjusted by T and N stage, age, sex, race, assigned cycles of fluorouracil, leucovorin, and oxaliplatin, KRAS and BRAF status, BMI, and Western diet.

4183 Background: High grade neuroendocrine neoplasms (HG-NENs) are treated with platinum doublets mirroring guidelines for small cell lung cancer (SCLC) but recurrences are common and salvage options are limited in efficacy. Cabozantinib (CABO), an inhibitor of VEGFR, MET, and TAM kinases (TYRO3, AXL, and MER) was approved by the FDA for treatment of well differentiated (WD) NENs of both pancreatic and extrapancreatic origins based on the CABINET study (Chan, NEJM 2025). However, its efficacy in the whole spectrum of HG-NEN patients including poorly differentiated disease (PDD) has not been prospectively explored. Methods: This was a single institution, Phase II study of CABO in patients with HG-NENs who had progressed on at least one prior treatment. Key inclusion/exclusion criteria were NENs of any origin except SCLC, high grade by Ki-67 of > 20% or histology consensus, ECOG of < = 1, appropriate hematological parameters and no history of bleeding or active cardiac disease. CABO was given orally starting at 60 mg po daily in 3-week cycles. The primary endpoint of this study was overall response rate (ORR). Secondary endpoints included progression free survival (PFS) and overall survival (OS). A Simon optimal 2-stage design tested the null hypothesis that the true ORR is < = 1% at the type I error rate of 5%, resulting in projected enrollment of up to 32 total patients. Toxicities were graded according to CTCAE v5.0 and response was evaluated according to RECIST v1. Results: All patients have been accrued, with 4/32 patients still on treatment. Median age at diagnosis was 62 years and male to female ratio was 1.46. Origin of tumor was GI in 68.8% of the cases, the rest being thoracic (6.3%), prostate (6.3%) cervical (6.3%) head/neck (3.1%) and unknown (9.4%). Median Ki-67 was 55%, 11 patients had Ki-67 > 70%. Histology was WD-HG in 40% of patients and PDD in 60%. Two patients had mixed PDD/other components (MiNEN). Median PFS in evaluable patients was 4.01 months [95% CI 1.61 to 9.30] and mOS was 9.89 mo [95% CI 6.73 to 18.96]. Three patients so far (9.3%) have had partial response as best response (PDD-colon, WD-pancreas and PDD-cervical) while 19/32 (59.4%) patients have had stable disease as best response so far (disease control rate 68.8%). Five (15.6%) patients have received more than 10 treatment cycles. The three longest treated patients had WD-pancreas (23 and 17 cycles) and PDD-unknown (12 cycles). One patient had eventual resection of a metastatic site and is currently without evidence of disease. Three patients withdrew from the trial because of toxicities (shortness of breath, GI bleeding, thromboembolism). Twenty-six patients have expired. Conclusions: CABO monotherapy showed efficacy in some HG-NEN patients with not just WD but also the very aggressive PDD histology. No new side effects to the ones previously described for this agent were noted. Supported by Exelixis and a Siteman investment program grant. Clinical trial information: NCT04412629 .

3630 Background: Lycopene, a non-provitamin A carotenoid, has been reported to inhibit colon cancer development; however, its prognostic role after colon cancer diagnosis remains unknown. Given emerging evidence suggesting greater intake of lycopene-containing – particularly, tomato-based – foods may improve colon cancer prognosis, we assessed the association of postdiagnosis lycopene consumption with survival among 1666 patients (pts) with stage III colon cancer. Methods: Through an NCI-sponsored multicenter phase III adjuvant chemotherapy trial (CALGB/SWOG 80702; NCT01150045), we examined the consumption of total lycopene (dietary plus supplementation) and dietary lycopene as well as lycopene-containing foods (tomato-based foods plus other lycopene-containing foods) and tomato-based foods via validated food frequency questionnaires (FFQs) collected at 6 weeks after randomization (FFQ1) and again 14-16 months post-randomization (FFQ2). Lycopene-related exposures were calculated as time-varying measurements via cumulative averaging. Primary outcome was disease-free survival (DFS), defined as time from FFQ1 completion to colon cancer recurrence or death from any cause. Secondary outcomes were recurrence-free survival (RFS) and overall survival (OS). We estimated associations of lycopene-related exposures with survival via multivariable Cox proportional hazards regression. Results: In our cohort, pts with greater total lycopene intake tended to be slightly younger and of male sex and White race, have more left-sided tumors, and report higher caloric intake and physical activity engagement. Over median follow-up of 6.0 (IQR: 5.0-6.1) years, we observed 466 DFS, 395 RFS, and 300 OS events. Pts in the highest relative to lowest quintiles of total lycopene intake experienced significantly improved DFS (HR: 0.60 [95% CI: 0.44-0.83]; P trend =0.006), RFS (HR: 0.58 [95% CI: 0.41-0.82]; P trend =0.007), and OS (HR: 0.60 [95%CI: 0.40-0.89]; P trend =0.02). Similar findings were observed for dietary lycopene intake. Pts consuming >1 serving/day compared to 1 serving/week of all lycopene-containing foods did not experience significantly improved survival. However, when considering only tomato-based foods, we observed a trend toward improved survival (HR for DFS: 0.61 [95% CI: 0.38-0.96]; P trend =0.12). Conclusions: Greater lycopene consumption with or without supplementation was associated with lower risk of colon cancer recurrence and death which may be largely driven by tomato-based foods. Our findings may inform clinical nutrition recommendations for pts with colon cancer, with higher intake of tomato-based foods (>1 serving per day) potentially improving colon cancer survival. Future studies, especially interventional trials, are needed to validate our findings. Support: U10CA180821, U10CA180882, U24CA196171; Pfizer; https://acknowledgments.alliancefound.org.

625 Background: In the TOPAZ-1 study (NCT03875235), durvalumab + gemcitabine and cisplatin (D+GC) significantly improved overall survival (OS) versus placebo + GC (P+GC) in participants (pts) with advanced biliary tract cancer. Updated results have shown a clinically meaningful long-term OS benefit for D+GC versus P+GC at 3 years. This exploratory analysis tested circulating tumor DNA (ctDNA) in plasma samples for blood-based detection of clinically actionable alterations (CAAs) and investigated the potential of this method to guide treatment decisions. Methods: Baseline genomic alterations were retrospectively assessed in evaluable tumor (FMI biomarker evaluable population [BEP], n=441) and plasma samples (GH BEP, n=643) using FoundationOne (Foundation Medicine Inc., Cambridge, MA) and Guardant INFINITY (Guardant Health, Redwood City, CA) assays, respectively. Mutation prevalence and association with outcomes were compared in the FMI BEP and GH BEP. Positive and negative percent agreement of CAAs detected in tumor versus ctDNA were assessed in 419 pts with both tumor and plasma samples (FMI-GH BEP). Results: The FMI BEP and GH BEP represented 64% and 94% of the TOPAZ-1 final analysis set (685 pts), respectively. The relative prevalence and overall mutational landscape detected in plasma ctDNA was consistent with that observed by tumor profiling, with the notable exception that genes harboring complex alterations (e.g. gene amplification, rearrangements, or homozygous deletions) were less frequently detected in ctDNA (e.g. ERBB2 , FGFR2 , and CKDN2A/2B/MTAP ). The most common alterations (>15% prevalence in both BEPs) observed were in TP53 (49%/52%), KRAS (24%/17%), and ARID1A (21%/16%) (in the FMI/GH BEPs, respectively). The relative prevalence of alterations within geographic and anatomic subgroups was similar in tumor versus plasma for most CAAs. The overall percent agreement in CAAs was ≥93%, and negative percent agreement was ≥97%. However, positive percent agreement was notably low for ERBB2 amplification (52%) and FGFR2 fusions (47%). OS hazard ratios for D+GC versus P+GC in the GH BEP were <1 for both CAAs and wild-type, except for ERBB2 amplification, as previously reported in the FMI BEP. Conclusions: The overall concordance and relative prevalence of simple mutations (e.g. single nucleotide variants) were similar using the FoundationOne tumor assay and Guardant INFINITY ctDNA assay, suggesting that plasma ctDNA testing has potential utility in clinical practice. However, negative status by ctDNA for the complex alterations found in FGFR2 and ERBB2 would require further testing of tumors, based on their low detectability in plasma. Clinical trial information: NCT03875235 .

PURPOSE ERBB2 overexpression/amplification in RAS/BRAF wild-type (WT) metastatic colorectal cancer (mCRC; human epidermal growth factor receptor 2 [HER2]-positive mCRC) appears to be associated with limited benefit from anti-EGFR antibodies and promising responses to dual-HER2 inhibition; however, comparative efficacy has not been investigated. We conducted a randomized phase II trial to evaluate efficacy and safety of dual-HER2 inhibition against standard-of-care anti-EGFR antibody–based therapy as second/third-line treatment in HER2-positive mCRC. METHODS Patients with RAS/BRAF -WT mCRC after central confirmation of HER2 positivity (immunohistochemistry 3+ or 2+ and in situ hybridization amplified [HER2/CEP17 ratio >2.0]) were assigned (1:1) to either trastuzumab plus pertuzumab (TP; trastuzumab 6 mg/kg and pertuzumab 420 mg once every 3 weeks) or cetuximab plus irinotecan (CETIRI; cetuximab 500 mg/m 2 and irinotecan 180 mg/m 2 once every 2 weeks) until progression or unacceptable toxicity. Crossover to TP was allowed after progression on CETIRI. The primary end point was progression-free survival (PFS). Secondary end points included objective response rate (ORR), overall survival, safety, and HER2 gene copy number (GCN ≥20/<20) as a predictive factor. RESULTS Between October 2017 and March 2022, 54 participants were assigned to TP (n = 26) and CETIRI (n = 28). Median PFS did not vary significantly by treatment: 4.7 (95% CI, 1.9 to 7.6) and 3.7 (95% CI, 1.6 to 6.7) months in the TP and CETIRI groups, respectively. Efficacy of TP versus CETIRI differed significantly by HER2 GCN (median PFS, GCN ≥20 [9.9 v 2.9 months] and GCN <20 [3.0 v 4.2 months], respectively; P interaction = .003). On TP, ORR was 34.6% (57.1% with GCN ≥20 v 9.1% with GCN <20) with median GCN of 29.7 versus 13.2 for responders and nonresponders, respectively ( P = .004). Grade ≥3 adverse events occurred in 23.1% and 46.1% of participants with TP and CETIRI, respectively. CONCLUSION TP appears to be a safe and effective cytotoxic chemotherapy-free option for patients with RAS/BRAF -WT, HER2-positive mCRC. Higher levels of HER2 amplification were associated with greater degree of clinical benefit from TP vis-à-vis CETIRI.

Table S3. Sensitivity analysis of the association between plasma 25-hydroxyvitamin level and disease-free survival, overall survival, and time to recurrence, excluding patients who recurred or died within three months of blood collection

TPS3648 Background: Indoleamine 2,3-dioxygenase 1 (IDO1) metabolizes tryptophan along the kynurenine pathway and is recognized as a potent suppressor of tumor reactive immunity. Epacadostat is an orally active, potent and selective inhibitor of IDO1. In preclinical studies, IDO1 was found to promote resistance to radiation in rectal cancer, irrespective of microsatellite instability (MSI) status. IDO1 inhibition with epacadostat improved tumor radiosensitivity by relieving immune suppression and augmenting radiation-induced apoptosis while protecting the normal intestine from radiation damage. In a phase 1 trial, 17 patients were enrolled from 4/2019 to 8/2023. Epacadostat in combination with short-course radiation therapy (SCRT) and CAPOX was well-tolerated and the recommended phase 2 dose (RP2D) of epacadostat was determined to be 400 mg BID. An NCI supported Phase 2 trial is ongoing to further evaluate the promising disease responses reported in the dose escalation phase. Methods: This phase 2 multicenter, open-label trial includes treatment and biomarker cohorts. In the treatment cohort, epacadostat at 400 mg BID will be administered concurrently with SCRT followed by epacadostat monotherapy until 1 day prior to neoadjuvant chemotherapy, followed by standard-of-care (SOC) neoadjuvant chemotherapy and, ultimately, surgical resection or non-operative management (NOM). Biomarker cohort enrollment will commence at completion of treatment cohort accrual. Enrolled patients will be treated with SOC SCRT followed by SOC neoadjuvant chemotherapy and surgical resection or NOM. Eligible patients must be a treatment-naïve, newly diagnosed, pathologically confirmed, locally advanced rectal cancer (defined by 8 th edition AJCC stage 2 or 3, or stage 1 not eligible for sphincter-sparing surgery) with plans to proceed with neoadjuvant SCRT and chemotherapy. The primary endpoint is the neoadjuvant rectal (NAR) score. Secondary endpoints are pathologic complete response (pCR) rate, complete clinical response (cCR) rate and progression-free survival (PFS). Exploratory endpoints are pharmacodynamics, PDX and organoid generation, identification of molecular predictors of response and resistance, correlation of radiographic and pathologic response and effect of treatment on patient quality of life. We aim to enroll 27 patients in the treatment cohort and 10 in the biomarker cohort. Clinical Trial Registration: NCT03516708 .

LBA14 Background: CALGB/SWOG 80702 previously showed that the addition of celecoxib to standard adjuvant chemotherapy with FOLFOX did not significantly improve disease-free survival (DFS) in patients with stage III colon cancer. Here, we evaluated the prognostic and predictive value of ctDNA in identifying a subpopulation of patients who may benefit from celecoxib. Methods: In the subset of patients with adequate biospecimens who participated in CALGB/SWOG 80702, a randomized phase III trial of 3 versus 6 months of adjuvant 5-FU, leucovorin, oxaliplatin (FOLFOX) +/- celecoxib, ctDNA assessment was performed using a clinically validated, tumor-informed 16-plex mPCR-NGS assay (Signatera(TM), Natera, Inc.) after surgery and before the start of adjuvant therapy (baseline). The Kaplan-Meier method was used to describe the distribution of survival time based on ctDNA positivity and log-rank testing was performed. Cox proportional hazards models were used to examine unadjusted associations between ctDNA positivity and disease-free (DFS) and overall survival (OS). Two-sided P values equal to or less than 0.05 were considered statistically significant, except for interaction P values (tested with a likelihood ratio). Results: In total, 1,011 of the 2,526 patients who participated in 80702 had ctDNA testing results from baseline; 189 were ctDNA positive (18.7%). ctDNA positivity associated with male sex, higher T stage, and N2 (versus N1) stage. ctDNA positivity was significantly associated with worse DFS (hazard ratio [HR] 6.52 [95% confident interval (CI) 5.09-8.34; p<0.0001] and OS (HR 6.28 [95% CI 4.63-8.51; p<0.0001]). Three-year DFS was 86.6% in ctDNA-negative cases and 36.8% in ctDNA-positive cases. Among patients who were ctDNA negative, celecoxib use was not significantly associated with worse DFS as compared to placebo (HR 0.75 [95% CI 0.54-1.05; p=0.095]) with a three-year DFS of 87.7% versus 85.5%, respectively. Among ctDNA-positive patients, celecoxib significantly improved DFS compared to placebo (HR 0.59 [95% CI 0.42-0.85; p=0.004]) with a three-year DFS of 44.1% versus 26.6% (P interaction = 0.25). Similar results were seen for overall survival with a hazard ratio of 0.86 (95% CI 0.56-1.33; p=0.49) for ctDNA negative cases and 0.63 (95% CI 0.41-0.96; p=0.028) for ctDNA-positive cases for celecoxib versus placebo (P interaction = 0.28). Conclusion: In a randomized phase III adjuvant therapy trial for stage III colon cancer, ctDNA was highly prognostic of DFS and OS. ctDNA positivity also appeared predictive of the benefit of adjuvant celecoxib for DFS and OS. These results suggest a potential role for ctDNA in determining which patients should consider celecoxib in addition to standard FOLFOX adjuvant therapy. Clinical trial information: NCT01150045 .

Supplementary Figure 1. Data supporting correlative analyses.

Figure S2. Dose-response relationship and test of linearity for the hazard ratio (HR) of disease-free survival (A), overall survival (B), and time to recurrence (C) by continuous predicted vitamin D scores, with reference of plasma 25-hydroxyvitamin D set at 12 ng/ml

Table S4. Hazard ratio of disease-free survival, overall survival, time to recurrence by quartiles of predicted vitamin D score

TPS4233 Background: Zunsemetinib (also known as ATI-450) is an investigational small molecule inhibitor targeting MAPK-Activated Protein Kinase (MAPKAPK2, or MK2). Preclinical work conducted by the Lim Lab at Washington University in St. Louis demonstrated that FOLFIRINOX activates heat shock protein 27 (Hsp27), a molecule with pleiotropic pro-survival properties, and beclin1, a key mediator of autophagy, in pancreatic ductal adenocarcinoma (PDAC) models. In an autochthonous PDAC (KPC) mouse model, zunsemetinib synergized with FOLFIRINOX, resulting in near-complete ablation of all PDAC foci and significantly improved mouse survival. Additionally, mice treated with zunsemetinib experienced significantly less intestinal damage and weight loss—common concerns associated with FOLFIRINOX. These preclinical data support the rationale for combining zunsemetinib with FOLFIRINOX in PDAC patients. Methods: We are conducting a phase I, single-arm, open-label study of zunsemetinib in combination with mFOLFIRINOX in patients with untreated metastatic PDAC. The study consists of two phases: a dose escalation phase and an expansion phase. During the dose escalation phase, zunsemetinib dosing will proceed according to the BOIN design with a cohort size of 3. A total of 6–21 patients will be enrolled at Washington University. Patients will receive zunsemetinib starting at Dose Level 1 (40 mg twice daily), with dose escalation continuing until the recommended phase 2 dose (RP2D) is determined. Patients will remain in the study until disease progression or treatment intolerance. In the expansion phase, up to 30 additional patients will be enrolled to further assess the toxicity profile of zunsemetinib in combination with mFOLFIRINOX. These patients will begin at the RP2D and continue on study treatment until disease progression or treatment intolerance. Eligible patients must be treatment-naïve, newly diagnosed, and have histologically or cytologically confirmed PDAC for which mFOLFIRINOX is deemed a suitable treatment option. The primary objective is to determine the dose-limiting toxicities (DLTs) and RP2D of zunsemetinib in combination with mFOLFIRINOX. Secondary objectives include assessing toxicity profiles, progression-free survival (PFS) at six months and overall PFS, disease control rate, overall response rate, overall survival, CA 19-9 response at the RP2D, and pharmacokinetics of zunsemetinib in PDAC treated with mFOLFIRINOX. Exploratory objectives include evaluating pharmacodynamic markers via immunohistochemistry (e.g., phospho-Hsp27 to assess pharmacodynamics of zunsemetinib, LC3B to assess autophagy, and TUNEL staining to evaluate DNA damage) and analyzing pathway suppression through RNA sequencing. Pre- and post-treatment serum samples will also be collected for the analysis of inflammatory cytokines. Clinical Trial Registration: NCT06648434. Clinical trial information: NCT06648434 .

Figure S1. Diagram for study cohort derivation

Table S2. Representativeness of study participants

TPS650 Background: The introduction of targeted treatment (tx) and immune checkpoint inhibitors (ICIs) has transformed the 1L advanced/metastatic (A/M) HCC tx landscape. 1 Combinations of ICIs with anti-angiogenic agents or other ICIs have demonstrated synergism in patients (pts) with A/M HCC, and shown improved efficacy versus single agents or tyrosine kinase inhibitors. 1,2 Combinations with anti-T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) and anti-programmed cell death protein-1 (PD-1) ICIs have shown promising anti-tumor activity in pts with solid tumors 3,4 including advanced HCC in US pts. 5 AMBER (NCT02817633) part 2F will evaluate the efficacy and safety of anti-TIM-3 cobolimab plus anti-PD-1 dostarlimab in tx-naïve pts with A/M and/or unresectable HCC. Methods: AMBER is a two-part, global, open-label, Phase Ib study assessing cobolimab as monotherapy or in combination with other drugs in pts with advanced solid tumors. For part 2F, ~45 pts are planned for enrollment. Key eligibility includes pts aged ≥18 years, with Eastern Cooperative Oncology Group (ECOG) performance score 0–1, histologically confirmed A/M HCC with measurable disease, Child-Pugh Class A liver function, no prior systemic tx, documented hepatitis B and C test at screening, and a pre-tx biopsy sample. Eligible pts will receive cobolimab (300 mg IV) plus dostarlimab (500 mg IV) every 3 weeks (Q3W) for up to 2 years or until progression, toxicity, discontinuation, or death. The primary endpoint is investigator-assessed objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1); secondary endpoints include investigator-assessed disease control rate (DCR), duration of response (DOR) and progression-free survival (PFS) per RECIST v1.1, and overall survival, alpha-fetoprotein response, and safety. Exploratory endpoints include immune-related (ir)-ORR, irDCR, irDOR and irPFS per irRECIST, and biomarker and pharmacokinetic assessments. Disease assessments will consist of CT/MRI evaluations of the chest, abdomen, and pelvis, Q9W from first dose then Q12W after 1 year of tx. Pts will undergo safety follow-up at 30 and 90 (±7) days after last study tx. Efficacy analysis will be based on the safety population (pts who receive ≥1 cobolimab dose) and will include summary statistics and point estimates with 2-sided 95% confidence intervals. Time-to-event analyses will be performed via Kaplan–Meier methods. After ~25 pts have been followed-up for ≥3 scans, an interim analysis may be performed. References: 1. Gordan JD, et al. J Clin Oncol . 2024:42:1830–50; 2. Finn RS, et al. N Engl J Med . 2020;382:1894–1905; 3. Curigliano G, et al. Clin Cancer Res. 2021;27:3620–29; 4. Davar D, et al. J ImmunoTher Cancer . 2023:11(Suppl 1):596; 5. Acoba JD, et al. J Clin Oncol . 2023:41:580. Funding: GSK (213348). Clinical trial information: NCT02817633 .

Table S5. Hazard ratio of cancer-specific mortality by plasma 25-hydroxyvitamin D levels in plasma biomarker companion study and by predicted vitamin D scores in diet and lifestyle companion study

Figure S3. Multivariable hazard ratio and 95% confidence intervals for disease-free survival (A), overall survival (B), and time to recurrence (C), comparing plasma 25-hydroxyvitamin D ≥12 versus <12 ng/ml, across strata of potential effect modifiers

Supplementary Table 1. Antibodies used in flow cytometry.