Citations

9009 Background: International Medical Graduates (IMGs) are a vital component of the US oncology workforce, representing nearly half of practicing medical oncologists. However, systemic barriers may influence their career trajectories differently. Understanding these challenges is essential for addressing workforce disparities and optimizing cancer care delivery across diverse geographic regions. Methods: We conducted a cross-sectional study of 13,497 medical oncologists using the 2024 Dec CMS Provider Dataset linked with the 2023 Rural-Urban Continuum Codes (RUCC). Medical oncologists were identified by their self-reported primary specialties, including Hematology/Oncology, Medical Oncology, and Hematopoietic Cell Transplant. Physicians were categorized by graduation origin (based on their self-reported medical school), career stage (early: 0–10 years, mid: 11–30 years, late: >30 years post-medical school graduation). The primary outcomes included practice at Main Campus of NCI Designated Cancer Centers (as an indicator of academic practice) and the geographical location of their practice (Metro, Non-Metro, Mixed). We employed chi-squared tests for statistical comparisons and performed stratified analyses by career stage to evaluate transition patterns over time. Results: 6920 IMGs constituted 48.7% of the oncology workforce, with similar gender distributions between IMG and non-IMG oncologists (37.9% vs 36.5% female, p=0.068). Notably, early career oncologists were less likely to be IMGs (IMG vs non-IMGs: 8.2% vs 12.5%, p<0.001). Compared to Non-IMGs, IMG oncologists are less likely to practice at main campuses of NCI Center (19.9% vs. 27.7%, p<0.001), especially as their career advances (all p<0.01). (Table). IMGs had higher representation in non-metropolitan areas than non-IMGs (11.4% vs 9.1%, p<0.001), particularly in late-career stages (14.7% vs 12.3%, p=0.033), indicating their unique role in serving underserved regions. (Table). Conclusions: Our findings reveal that, IMGs are less likely to practice at main campuses of NCI-Cancer Center than their non-IMG colleagues. Meanwhile, IMG oncologists are disproportionately serving rural communities. Supporting IMG pathways in oncology is critical to ensure a balanced cancer care delivery across the United States. Practice setting distribution and academic affiliation among international medical graduates (IMGs) and US graduates (USGs) by career stage. IMG (N=6,577) Non-IMG (N=6,920) IMG (N=6,577) Non-IMG (N=6,920) NCI Center Other NCI Center Other Metro Non-Metro/Mixed Metro Non-Metro/Mixed Total 19.9% 80.1% 27.7% 72.3% 88.6% 11.4% 90.9% 9.1% Career Stage Early (0-10y) 29.1% 70.9% 36.1% 63.9% 91.1% 8.9% 95.4% 4.6% Mid (11-30y) 21.3% 78.7% 28.8% 71.2% 90.1% 9.9% 91.6% 8.4% Senior (30+y) 15.0% 85.0% 22.0% 78.0% 85.3% 14.7% 87.7% 12.3%

e16479 Background: Recent genomic data has demonstrated SBA to be a molecularly unique entity when compared to colon or gastric cancers. The ongoing SWOG 1922 randomized clinical trial is comparing FOLFIRI to ramucirumab/paclitaxel as the second-line treatment for metastatic SBA. We sought to further define the activity of taxane-based therapy in the largest collection of SBA patients treated with this therapy. Methods: A retrospective review of SBA patients treated with taxane-based chemotherapy from 1994 to 2024 at MD Anderson Cancer Center was performed. All patients had pathologic confirmation, received > 1 cycle of therapy, and had documented tumor response evaluation. Response was assessed by the treating physician based on the imaging studies and categorized as response, stable disease or progression. Patient demographics, clinical parameters, molecular data, and taxane treatment was reviewed. Kaplan-Meier survival analysis was performed to calculate time to progression (TTP) and overall survival (OS). Results: 70 SBA patients treated with taxane-based therapy were identified. The median age at diagnosis was 57 years (range 33-80 years), majority being male (59%) with primary tumor located at duodenum (44%), Jejunum (34%), Ileum (16%). The most common presenting metastatic site was peritoneum (39%), followed by liver (31%). The genomic status revealed mutations in the following genes: 62% TP53, 47% KRAS, 24% SMAD4, and 15% APC. Taxane treatment was single agent (nab-paclitaxel, paclitaxel, or docetaxel) in 29%, gemcitabine and taxane combination in 61% and other taxane-based combinations in 10%. Therapy was given in the metastatic setting as 2nd-line in 40%, 3rd-line in 33% and 4th-line or greater in 20%. Response status was response in 24%, stable disease in 26%, and progression in 50%. Median TTP was 3.1 months (95%CI: 2.0-4.2 months), and median OS was 8.7 months (95%CI: 7.4-10.1 months). Median TTP was similar between single agent (2.6 months) and gemcitabine-based combination (2.5 months) (p =0.75). Efficacy did not differ by line of therapy nor primary tumor site. Efficacy differed by TP53 mutation status: TP53 mutated vs wildtype (response 21% vs 43%, p = 0.02; median TTP 2.4m vs 4.9m, p = 0.013; median OS 7.3m vs 10.6m, p = 0.004). Conclusions: This retrospective study of 70 SBA patients confirms the activity of taxane-based therapy demonstrating a response rate of 24% and median TTP of 3.1 months. Though limited by sample size, TP53 mutations may represent a negative predictive marker for taxane-based therapy in SBA patients. These findings support the ongoing SWOG 1922 trial investigating taxane-based therapy as a second line for metastatic SBA.

2085 Background: Primary Central Nervous System Lymphoma (PCNSL) is a rare and aggressive non-Hodgkin lymphoma with no approved treatments for relapsed/refractory (R/R) patients, representing a critical unmet need. MyD88 mutations in ~70% of PCNSL patients drive Interleukin-1 receptor associated kinase 4 (IRAK4) activation, promoting NF-κB signaling, inflammation, and tumor progression. Emavusertib, a potent oral IRAK4 inhibitor, crosses the blood-brain barrier and shows preclinical synergy with Bruton tyrosine kinase inhibitors (BTKi), re-sensitizing BTKi-resistant cell lines. This study evaluates the molecular and pharmacokinetic (PK) data associated with responses to emavusertib + ibrutinib combination therapy in R/R PCNSL patients. Methods: The safety, clinical activity, and potential biomarkers of emavusertib in R/R PCNSL are being investigated in the ongoing open-label, Phase 1/2 TakeAim Lymphoma trial (NCT03328078). Pre-dose and 1.5-hour post-dose plasma samples were collected on Cycle 3 Day 1, Cycle 5 Day 1 and Cycle 7 Day 1. Cerebrospinal fluid (CSF) samples were obtained via a lumbar puncture within 1.5 hrs of collection of the post-dose plasma PK sample on Cycle 3 Day 1. Mutation analysis was based on patients’ molecular pathology reports provided by trial sites. Sequencing of archival tissues, CSF and plasma are in progress. Results: As of 06 December 2024, CSF concentration data were available for 7 PCNSL patients. The mean emavusertib concentration in CSF was 81.3 ng/ml (54.7-104.0) in patients receiving 100 mg emavusertib BID (n = 4). In patients receiving 200 mg emavusertib BID (n = 3), the mean emavusertib concentration in CSF was higher at 175.7 ng/ml (114.8-209.4), which is 2.2X the mean value in patients who received 100 mg emavusertib BID (p-value = 0.02). All 7 patients received 560 mg ibrutinib QD, and the ibrutinib concentrations in the CSF were consistent with findings from previously published clinical studies. MyD88 mutation status was available for 7 patients of which all had prior exposure to BTKi regimens. Among these, 6 patients had MyD88 mutation of which 4 patients had responded (3 complete responses and 1 partial response) to emavusertib + ibrutinib combination with duration of response (DOR) up to 18.9 months with data collection ongoing. Conclusions: Preliminary CNS pharmacokinetic data demonstrates that emavusertib concentration in CSF increases with increasing emavusertib dose. Patients with MyD88 mutations showed expected promising preliminary efficacy to emavusertib + ibrutinib combination and may overcome BTKi resistance. Enrollment in this trial is ongoing. Clinical trial information: NCT03328078 .

7037 Background: TRANSCEND CLL 004 (NCT03331198) is a phase 1/2, open-label, nonrandomized, multicohort study in adult patients (pt) with R/R chronic lymphocytic leukemia/small lymphocytic lymphoma with liso-cel mono and liso-cel + ibrutinib combo cohorts. Given the study design, we performed PS matching/weighting to adjust for differences in key covariates between cohorts to compare efficacy and safety. Methods: Here, PS is the probability of receiving combo given the covariates and estimated by logistic regression. Covariates were hemoglobin, LDH, number of prior therapies, platelets, prior BTKi + venetoclax exposure, R/R on prior BTKi, and bulky disease for efficacy; and ALC, bulky disease, CRP, ferritin, and number of prior therapies for safety. PS balancing methods were optimal 1:1 matching, average treatment effect for treated pts (ATT) full matching, and ATT inverse probability of treatment weighting (IPTW). Efficacy endpoints were response (CR rate, ORR) and time to event endpoints (DOR, PFS, OS). Safety endpoints were proportions of pts with any-grade (gr)/gr ≥ 3 cytokine release syndrome (CRS) and investigator-identified neurological events (NE). Results: Fifty-one and 88 efficacy-evaluable pts were treated at dose level 2 (100 × 10 6 CAR + T cells) in the combo and mono cohorts, respectively. Before matching/weighting on PS, odds of achieving CR and overall response were statistically significantly higher for combo (Table). DOR did not differ between cohorts. For PFS and OS, HRs were lower with combo vs mono (not statistically significant [NS]). Odds of gr ≥ 3 CRS/NE were lower with combo vs mono (NS). After matching/weighting, odds of CR (except IPTW ATT) and overall response remained statistically significantly higher in combo. HRs for PFS and OS and ORs for gr ≥ 3 CRS/NE were numerically lower with combo vs mono (NS, except IPTW ATT for PFS). HRs for DOR were less but close to HR of 1. Conclusions: The liso-cel + ibrutinib combo demonstrated a trend for better efficacy and safety vs liso-cel mono, with statistically significant differences for CR rate and ORR. Clinical trial information: NCT03331198 . Efficacy and safety outcomes: combo vs mono. No adjustment ATT optimal 1:1 IPTW - ATT CR rate, OR (95% CI) 2.07* (1.01–4.28) 2.40* (1.05–5.66) 2.00(0.89–4.61) ORR, OR (95% CI) 3.96* (1.68–10.51) 3.43* (1.33–9.71) 4.18* (1.63–11.78) DOR, HR (95% CI) 0.98(0.51–1.87) 0.88(0.43–1.78) 0.96(0.50–1.85) PFS, HR (95% CI) 0.62(0.37–1.02) 0.61(0.35–1.05) 0.59* (0.35–0.98) OS, HR (95% CI) 0.70(0.38–1.28) 0.73(0.37–1.43) 0.66(0.36–1.22) CRS, OR (95% CI) 0.63(0.26–1.56) 0.67(0.24–1.84) 0.69(0.24–1.88) Gr ≥ 3 CRS, OR (95% CI) 0.23(0.01–1.35) 0.49(0.02–5.28) 0.26(0.01–1.94) NE, OR (95% CI) 0.84(0.41–1.68) 0.92(0.40–2.08) 1.10(0.48–2.52) Gr ≥ 3 NE, OR (95% CI) 0.56(0.19–1.45) 0.58(0.16–1.89) 0.68(0.19–2.30) *Statistically significant difference at 5% level.

TPS625 Background: Approximately 50% of newly diagnosed invasive breast cancers are stage 1, with the majority being ER/PR-positive, HER2-negative. Genomic assays such as the Oncotype DX have identified patients (pts) with reduced risk of distant metastasis and without benefit from chemotherapy added to endocrine therapy (ET), freeing them from excess toxicity. Genomic assays are also recognized as prognostic for in-breast recurrence (IBR) after breast-conserving surgery (BCS) and could similarly allow de-escalation of adjuvant radiotherapy (RT). Reducing overtreatment is of interest to pts, providers, and payers. Methods: We hypothesize that BCS alone is non-inferior to BCS plus RT for IBR and breast preservation in women intending ET for stage 1 invasive breast cancer (ER and/or PR-positive, HER2-negative with an Oncotype DX Recurrence Score [RS] of ≤18). Stratification is by age (<60; ≥60), tumor size (≤1 cm; >1-2cm), and RS (≤11, >11-18/MammaPrint Low). Pts are randomized post-BCS to Arm 1 with breast RT using standard methods (moderate or ultra hypo- or conventional-fractionated whole breast RT with/without boost, or APBI) with ≥5 yrs of ET (tamoxifen or AI) or Arm 2 with ≥5 yrs of ET (tamoxifen or AI) alone. The specific regimen of ET in both arms is at the treating physician’s discretion. Eligible pts are stage 1: pT1 (≤2 cm), pN0, age ≥50 to <70 yrs, s/p BCS with negative margins (no ink on tumor), s/p axillary nodal staging (SNB or ALND), ER and/or PR-positive (ASCO/CAP), HER2-negative (ASCO/CAP), and Oncotype DX RS ≤18 (diagnostic core biopsy or resected specimen). A “low risk” MammaPrint is permissible if completed as part of usual care prior to screening. Primary endpoint is IBR (invasive breast cancer or DCIS). Secondary endpoints are breast conservation rate, invasive in-breast recurrence, relapse-free interval, distant disease-free survival, overall survival, patient-reported breast pain, patient-reported worry about recurrence, and adherence to ET. We assume a clinically acceptable difference in IBR of 4% at 10 yrs to judge omission of RT as non-inferior (10-yr event-free survival for RT group is 95.6% v 91.6% for the omission-of-RT group). BR007 is powered to detect non-inferiority with 80% power and a one-sided α=0.025, assuming that there would be a ramp-up in accrual in the first two years (leveling off in Yrs 3-5); 1,670 pts (835 per arm) are required for randomization. Conservative loss to follow-up is 1%/yr. Some T1a pts screened may have Oncotype DX scores >18, making them ineligible for the study. In the accrual process, 1,714 pts will be required to register to ensure that our final randomized cohort is 1,670 pts. As of 1-6-2025: 1,168/1,670 pts have been randomly assigned, and 1,294 screened. Support: U10 CA180868, -180822, UG1 CA189867. Clinical trial information: NCT04852887 .

TPS2094 Background: Liquid biopsy in glioblastoma (GBM) is hindered by a lack of requisite circulating tumor (ct) and cell-free (cf) DNA levels in blood due to the blood-brain barrier (BBB). This limits the identification of blood-based tumor biomarkers along with the development and use of biomarker-driven systemic therapies. Low intensity focused ultrasound combined with intravenously administered microbubble oscillators (MB-FUS), leads to non-invasive BBB opening. This trial aims to evaluate the utility of LIFU for bolstering blood ctDNA and cfDNA for enhance liquid biopsy in patients with GBM. Methods: LIBERATE is an ongoing, prospective, multi-center, self-controlled, pivotal trial evaluating safety and technical efficacy of transcranial MR-guided MB-FUS for increasing blood ctDNA and cfDNA levels in adults, aged 18-80 years with GBM. Patients with suspected GBM planned for tumor biopsy or resection at 17 centers in US and Canada are being enrolled. Patients with multifocal tumors or tumors arising from deep midline, thalamus, cerebellum, or brainstem are excluded. Patients are administered IV microbubbles for enhanced sonication, after which MR-guided BBB opening using a 220 kHz device, with 1024-element phased array transducer, is performed with real-time acoustic feedback control for effective cavitation. Pre- and post-procedure, phlebotomy and MRI brain are done. Patients are offered optional 2 nd procedure during adjuvant chemotherapy phase if willing. Primary efficacy endpoint is correlation between biomarker patterns in tumor tissue collected during surgery/biopsy and blood collected following MB-FUS procedure. Confirmatory secondary efficacy endpoint is ratio between greatest yield of cfDNA in blood post-MB-FUS compared to cfDNA level in blood pre-MB-FUS. The primary study hypothesis is that agreement rate on biomarker pattern between resected/biopsied tumor tissue and blood is > 70%. The secondary hypothesis is that MB-FUS BBBO leads to a ≥2-fold rise in blood cfDNA. Assuming the true agreement rate expected is 89%, a sample of N = 50 patients will provide 90% power to meet the primary endpoint (Exact test, Binomial Proportion, one-sided Alpha = 0.025). Exploratory endpoints include (1) sensitivity of detection of known specific somatic mutations in ctDNA from blood samples collected before and after MB-FUS, (2) estimation of ctDNA levels in samples collected at 30-minutes, 1-hour, 2-hour, and 3-hour post-MB-FUS to determine time of greatest yield, (3) correlation of MRI parameters related to grading of BBB opening and ctDNA-based biomarkers from post-MB-FUS blood samples, (4) biomarker correlation between plasma cfDNA sampled during adjuvant chemotherapy phase and tumor tissue harvested at surgery. Patient enrollment commenced in 2022 and is ongoing (NCT05383872). Clinical trial information: NCT05383872 .

7023 Background: Axi-cel is an autologous chimeric antigen receptor (CAR) T-cell therapy approved for adults with R/R LBCL after ≥ 1 prior line of therapy (LoT). Adverse events, such as cytokine release syndrome (CRS) and neurologic events (NEs), may deter centers from using axi-cel in an outpatient (OPT) setting, though individual centers have observed comparable safety and effectiveness in OPT and inpatient (IPT) care (Furqan et al. Blood Adv . 2024). Here, we present safety and effectiveness outcomes of axi-cel by intention to treat in OPT and IPT settings in a multicenter real-world dataset. Methods: Pts receiving axi-cel for R/R LBCL in the US from 01/2021-07/2023 with data in the Center for International Blood and Marrow Transplant Research (CIBMTR) registry were eligible for analysis. Pts with prior allogeneic transplant or unknown intended care setting were excluded. Of potential pts, 119 OPT pts were identified from 29 centers where an increasing trend was seen (9.6% of pts in 2021 were OPT, 13.5% in 2022, 22.8% in 2023). Pts were matched to 119 IPT pts by propensity score matching on age, sex, comorbidities, lactate dehydrogenase (LDH), bulky disease, prior LoT, chemosensitivity, and infusion year (see table). Results: OPT pts had median age of 63 y (25% ≥ 70), 66% were male, and 67% had ≥ 1 comorbidity. Half (50%) had elevated LDH and 73% had 1 prior LoT. Bulky disease was reported in 3%, and 60% had chemo-resistant disease. Outcomes were analyzed at median follow-up of 12 mo. Safety and effectiveness outcomes were similar between OPT and IPT pts (see table). In multivariate analyses, no differences were found between intended care setting and CRS (odds ratio [OR] 1.09 [95% CI 0.51-2.35]), CRS Gr ≥ 3 (OR 0.57 [0.12-2.60]), NEs (OR 1.14 [0.65-2.00]), or NEs Gr ≥ 3 (OR 0.98 [0.48-2.00]). Among OPT pts, 24% and 50% did not require hospital admission within 30 d and 3 d, respectively. In pts aged ≥ 70 y, only any Gr NEs were higher in the OPT group. Conclusions: After matching on key factors that may be used to select pts for OPT infusion, outcomes were comparable between intended care settings. These findings corroborate prior results and support the consideration of axi-cel in appropriate OPT care settings. Outcomes between matched pts with R/R LBCL receiving axi-cel intended for OPT or IPT. OPT (n=119) a IPT (n=119) a CRS any Gr / Gr ≥ 3 83 (75−89) / 3 (<1−7) 83 (74−89) / 4 (1−10) NE any Gr / Gr ≥ 3 47 (38−57) / 19 (12−27) 46 (37−56) / 21 (14−30) Overall / complete response rates 78 (69−85) / 68 (59−76) 76 (67−83) / 62 (52-70) Duration of response @ 12 mo 64 (52−74) 69 (58−78) Progression-free survival @ 12 mo 53 (43−62) 53 (43−61) Overall survival @ 12 mo 71 (61−78) 72 (62−79) Non-relapse mortality @ 12 mo 6 (2−11) 4 (1−8) Hospital admission within 30 days of infusion / median duration (range), d 76 (67−83) / 9 (2−53) Not Applicable a Percent (95% CI) unless otherwise specified.

e15628 Background: Total neoadjuvant therapy (TNT) with cytotoxic chemotherapy and chemoradiation followed by surgical resection is a standard treatment for locally advanced rectal cancer (LARC). In a limited number of LARC patients with deficient mismatch repair (dMMR), treatment with an immune checkpoint inhibitor (ICI) resulted in all patients achieving complete clinical response (cCR) (median follow-up of 29 months) such that radiotherapy and surgery were avoided. These and other data have resulted in the routine use of neoadjuvant ICI for dMMR LARC. Here we report a multicenter series of patients with dMMR LARC treated with neoadjuvant ICI. Methods: Adult patients (N = 21) with dMMR LARC who received neoadjuvant ICI at Mayo Clinic, MD Anderson Cancer Center, Duke University or University of Pittsburgh were identified from the electronic medical record (EMR) and relevant data were abstracted. All patients were staged with pelvic MRI; clinical response was evaluated by repeat pelvic MRI and sigmoidoscopy. Data were summarized using descriptive statistics. This study was approved by the Mayo Clinic IRB. Results: Patients with clinical stage I (n = 2), II (n = 3) or III (n = 15) dMMR LARC were treated with neoadjuvant PD-1 monotherapy (n = 20) or combination (n = 1, ipilimumab+ nivolumab). Median age was 46 years (IQR 39, 65), 15 (71%) were male, 10 (48%) had distal tumors, and 14 had Lynch Syndrome. Median duration of ICI treatment was 7 mos (IQR 6, 12); one patient remains on dostarlimab at data cut-off. Clinical complete response (cCR) was achieved in 11 (52%) patients, partial response (PR) in 7 (33%), stable disease (SD) in 1 (5%), and progressive disease (PD) in 2 (10%) patients. Median time from first dose of ICI to best clinical response was 6 mos (IQR 5, 8) months. All partial or non-responders received salvage TNT with (n = 6) or without (n = 3) surgery. At a median follow up of 19 mos (range 6 to 56), tumor regrowth occurred in 1 patient who was subsequently treated with TNT. Any grade immune-related adverse event occurred in 6 (29%) patients; one grade 3 hepatitis occurred in the patient on Ipi+Nivo (Table1). Conclusions: Neoadjuvant ICI treatment of dMMR LARC resulted in half of treated patients achieving cCR. Careful monitoring is necessary to identify non responders who will require salvage TNT. Patient characteristics and clinical response to ICI. ID Sex Age Stage ICI Response to ICI ID Sex Age Stage ICI Response to ICI 1 M 62 T3N+ Pembro cPR 12 M 37 T3N+ Pembro cCR 2 M 60 T2N0 Pembro cCR 13 M 41 T3N0 Pembro cCR 3 M 80 T2N0 Pembro cPD 14 M 46 T4N+ Pembro cPR 4 M 36 T3N+ Ipi+Nivo cCR 15 M 68 T3N+ Pembro cPR 5 M 57 T3N+ Dostarli cCR 16 M 77 T3N0 Pembro cPR 6 M 39 T3N+ Dostarli cPR 17 M 40 T4Nx Pembro cCR 7 F 44 T2N+ Dostarli cPD 18 F 35 T3N+ Dostarli cCR 8 M 74 T3N+ Pembro cCR 19 M 60 T2N+ Pembro cPR 9 M 43 T3N+ Nivo cCR 20 F 65 T3N+ Pembro cCR 10 F 81 T3N0 Dorstali cPR 21 F 39 T4N+ Dorstali cSD 11 F 32 T2N+ Pembro cCR

e15581 Background: Sentinel lymph node (SLN) assessment is critical in colorectal cancer (CRC) for accurate staging and determining optimal treatment strategies. The one-step nucleic acid amplification (OSNA) assay, which measures cytokeratin 19 (CK19) mRNA expression, has shown potential as a molecular diagnostic tool for the intraoperative detection of SLN metastases. This study aims to evaluate the diagnostic accuracy of OSNA for SLN metastasis in CRC. Methods: A systematic search was conducted in PubMed, Cochrane Library, and Web of Science for studies published up to December 2024. Studies reporting diagnostic accuracy metrics for OSNA in detecting SLN metastases in CRC were included. R software (version 4.0.3) with the mada package was used to compute pooled sensitivity, specificity, false-positive rates, diagnostic odds ratios (DOR), and likelihood ratios (LR), all expressed within 95% confidence intervals (CI). Results: Six studies involving 3,016 patients, of whom 363 had SLNs, were included. The pooled sensitivity of OSNA was 91% (95% CI: 84.8–94.8%), while the specificity was 95.6% (95% CI: 91.7–97.8%). The diagnostic odds ratio (DOR) was 220.59 (95% CI: 74.02–657.43). The false-positive rate was 4.4% (95% CI: 2.2–8.3%). The positive likelihood ratio (LR+) was 20.8 (95% CI: 10.5–41.2), and the negative likelihood ratio (LR−) was 0.09 (95% CI: 0.05–0.16). These findings demonstrate that in diagnostic accuracy, OSNA outperforms traditional histopathological methods, such as hematoxylin and eosin (H&E) staining. Conclusions: OSNA demonstrates superior diagnostic accuracy for detecting SLN metastases in colorectal cancer, supporting its integration into clinical workflows. Its high diagnostic accuracy and rapid intraoperative turnaround time make it an invaluable resource for improving surgical decision-making. However, variability in CK19 expression across tissues and the lack of standardized assay thresholds remain challenges that require further investigation. However, its adoption has the potential to enhance staging accuracy and improve surgical and oncological outcomes, warranting broader implementation in CRC management.

TPS3171 Background: Genetic alterations in fibroblast growth factor receptors 2 and 3 ( FGFR2/3 ) occur in nearly all cancer types. FGFR2 fusions and rearrangements occur in up to 10-15% of intrahepatic cholangiocarcinomas (iCCA) and alterations in FGFR3 occur in 15-30% of urothelial cancers. The clinical benefit from currently approved FGFR inhibitors (FGFRi) is often curtailed by development of acquired resistance, which may arise through on-target mutations in the FGFR2/3 kinase domain. Additionally, off-tumor effects on FGFR1 by pan-FGFRi can lead to hyperphosphatemia and consequently to dose reductions or dose holds. Thus, there is an unmet clinical need for a selective FGFR2/3 inhibitor that has clinical efficacy against activating alterations and resistance mutations without causing FGFR1-mediated hyperphosphatemia. CGT4859 is an orally bioavailable, ATP-competitive, reversible inhibitor of FGFR2/3, with potency against clinically relevant FGFR2/3 kinase domain mutations. In addition, CGT4859 demonstrates >140 fold selectivity over FGFR1, and shows robust efficacy in target altered in vivo tumor models without increases in serum phosphorus. Nonclinical pharmacokinetics (PK) and safety data support evaluating CGT4859 in a first-in-human, open-label, dose-escalation and signal-seeking Phase I/II study (NCT06777316). Safety, tolerability, PK, pharmacodynamics, and antitumor activity of CGT4859 will be assessed in adults with histologically confirmed unresectable or metastatic iCCA or other solid tumors with FGFR2/3 alterations. Methods: CGT4859 will be administered orally continuously in 28-day cycles to patients (N=~50) at a starting dose of 1 mg QD, and dose escalation will not exceed 40 mg QD as determined using a Bayesian optimal interval design with backfill (BF-BOIN). This approach will be used to guide dose escalation and establish the maximum tolerated dose (MTD) and recommended Phase 2 Dose (RP2D). BF-BOIN enables backfilling of participants to doses that are cleared for safety during the dose escalation, generating additional data on safety and tolerability below the MTD. Objective response rate (ORR) and disease control rate will be determined based on investigator assessment using RECIST v1.1. Phase II will enroll up to 4 cohorts, each enrolling ~15 patients. Proposed cohorts will include participants who have iCCA and are either FGFRi-naïve or FGFRi-exposed. Two additional cohorts with other advanced solid tumors harboring FGFR2/3 alterations may be included based on signals detected in dose escalation. The primary efficacy endpoint for Phase II is ORR per RECIST v1.1. The preclinical data support the study of CGT4859 in this patient population with solid tumors harboring FGFR2 and/or FGFR3 genetic alterations. The phase I dose escalation study is currently enrolling at sites in the United States. Clinical trial information: NCT06777316 .