Chan, Jennifer Ai-wen

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 .

ASCO Guidelines provide recommendations with comprehensive review and analyses of the relevant literature for each recommendation, following the guideline development process as outlined in the ASCO Guidelines Methodology Manual . ASCO Guidelines follow the ASCO Conflict of Interest Policy for Clinical Practice Guidelines . Clinical Practice Guidelines and other guidance (“Guidance”) provided by ASCO is not a comprehensive or definitive guide to treatment options. It is intended for voluntary use by clinicians and should be used in conjunction with independent professional judgment. Guidance may not be applicable to all patients, interventions, diseases or stages of diseases. Guidance is based on review and analysis of relevant literature and is not intended as a statement of the standard of care. ASCO does not endorse third-party drugs, devices, services, or therapies and assumes no responsibility for any harm arising from or related to the use of this information. See complete disclaimer in Appendix 1 and 2 (online only) for more. PURPOSE To develop a clinical practice guideline and recommendations for symptom management of patients with well-differentiated grade 1 to grade 3 metastatic gastroenteropancreatic neuroendocrine tumors. METHODS ASCO convened an Expert Panel to develop a clinical practice guideline by reviewing the literature for relevant guidelines, systematic reviews, randomized controlled trials (RCTs), and observational studies to develop recommendations for clinical practice. RESULTS The literature review identified eight guidelines, 19 systematic reviews, and three RCTs that informed the development of guideline recommendations. RECOMMENDATIONS Recommendations are included for carcinoid syndrome, carcinoid heart disease and carcinoid crisis, and functional pancreatic neuroendocrine tumor syndromes. Recommendations are provided for surgical management, liver-directed therapy, and systemic therapy options, as well as palliative care. Limited guidance is provided for sequencing of interventions. Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines .

666 Background: In the phase 3 CABINET trial (NCT03375320), cabozantinib (CABO) significantly prolonged median progression-free survival (PFS) compared to placebo (PB) in patients with advanced, previously treated, progressive extrapancreatic NET (epNET) [HR 0.38 (95% CI, 0.25-0.59, P<0.0001)] and pancreatic NET (pNET) [HR 0.23 (95% CI, 0.12-0.42, P<0.0001)] (Chan et al., NEJM, 2024). In this analysis, we focus on outcomes of patients with epNET arising in the GI tract. Methods: Patients with locally advanced or metastatic epNET or pNET were randomized 2:1 in separate cohorts to receive CABO 60 mg daily vs PB. The epNET cohort included patients with tumors arising in the GI tract (not including pancreas), lung, unknown primary, and other rare primary sites. In this subgroup analysis of the epNET cohort, patients with GI NET were included. Eligibility included progression by RECIST within 12 months (mo) prior to registration, ≥ 1 prior systemic therapy. Primary endpoint: PFS by blinded independent central review (BICR). Secondary endpoints: objective response rate, overall survival, safety. Results: 116 of the 203 patients in the epNET cohort had GI NET (CABO, n=70; PB, n=46). Median age was 66 yrs; females: 46%; G1/G2/G3/unknown grade: 35%/57%/6%/2%. ECOG performance status: 0/1-2: 43%/57%. White race: 86%. The most common primary tumor locations were ileum/cecum (54%), small intestine with location not specified (20%); non-cecum colon or rectum (11%), stomach (4%); duodenum (3%); jejunum and nonspecified midgut site (3% each). Prior systemic therapies included somatostatin analogs (SSA) (100%), everolimus (59%); Lu-177 dotatate (77%); temozolomide +/- capecitabine (16%). In patients with GI NET, CABO was associated with improved PFS by BICR compared to PB (stratified HR, 0.50; 95% CI: 0.28-0.88, 1-sided stratified log-rank P=0.007). Median PFS with cabozantinib was 8.5 mo (95% CI, 6.0-16.7) compared to 5.6 mo (95% CI, 3.9-11.0) with PB. CABO demonstrated potential benefit in patients with midgut GI NET and across clinical factors including grade, functional status related to hormone secretion, concurrent SSA use, and prior therapy with Lu-177 dotatate or everolimus. The most frequent grade 3/4 adverse events attributed to therapy with CABO included hypertension (19%), diarrhea (13%), fatigue (10%). Conclusions: CABO is associated with improvement in PFS compared to PB in patients with advanced GI NET. Potential benefit was observed across clinical factors including grade, functional status, concurrent SSA, and prior treatment. The safety profile for CABO in patients with GI NET is consistent with that previously reported. Support: U10CA180821, U10CA180882; U10CA180820 (ECOG-ACRIN), U10CA180868 (NRG Oncology), U10CA180888 (SWOG); Exelixis; https://acknowledgments.alliancefound.org . Clinical trial information: NCT03375320 .

Abstract Posterior Fossa Group A (PFA) ependymomas are pediatric brain tumors with extremely poor survival outcomes. As protein-coding mutations in PFA are exceedingly rare, the underlying etiology of these tumors remains elusive. Elevated CpG island methylation and depletion of H3K27me3 have been described in PFA, leading to the hypothesis that PFA may be driven by a dysregulated epigenetic state. In this study, we sought to determine how three-dimensional (3D) genome features (such as DNA loops, domains, and compartments) differ between pediatric brain tumors. We performed Hi-C sequencing on a collection of 64 patient specimens and patient-derived primary cultures that collectively span multiple subgroups of ependymoma, medulloblastoma, high-grade glioma, and non-neoplastic brain. For certain samples, we further performed RNA-seq, histone modification ChIP-seq, or whole-genome bisulfite sequencing to allow multiomic data integration. Overall, the 3D genome organization of PFA samples appeared distinct from other tumor types. We identified and defined TULIPs: a subset of type B compartments, separated by genomic distances greater than 10 Mbp, that exhibit a striking fivefold increase in reciprocal interaction strength. These TULIPs recurred at the same genomic positions across the vast majority of PFA samples with minimal representation among other tumor or non-tumor samples. TULIPs displayed enrichment for heterochromatic features such as H3K9me3 and late replication timing and were depleted of euchromatic features such as H3K27ac and protein-coding genes. By using immuno-fluorescence for H3K9me3 and oligo-FISH to label TULIP regions, we demonstrated that TULIP regions are more compact in PFA than other tumors. Finally, by applying inhibitors of H3K9 lysine methylation to PFA cultures we showed that TULIPs become more diffuse and cell viability is reduced. Altogether, this work defines TULIPs as highly recurrent epigenetic features of PFA tumors.