Soares, Heloisa P.

Abstract Introduction: Next generation of Theranostics studies are looking at novel combinations with radiation sensitizers to enhance PRRT’s efficacy. Here, we present safety and efficacy data from a multi-center phase 1 study of a [¹⁷⁷Lu]lutetium-dotatate -triapine combination in patients with GEP-NETs. Methods: The study consisted of two phases (dose escalation and expansion) administering the recommended phase 2 doses (RP2D) for the two agents. All patients received 200 mCi of [¹⁷⁷Lu]lutetium-dotatate on day 1 of four 8-week cycles, in combination with oral triapine administered at assigned dose levels (100 mg, 150 mg or 200mg) from days 1 to 14 of each cycle. Results: A total of 31 (A: 15 ; B: 16 ) patients received treatment. Nine patients experienced dose-limiting toxicities; Grade 3 anemia (n=1), Grade 5 cardiac arrest (n=1), and Grade 4 neutropenia (n=7). Based on the overall safety and pharmacokinetics data, a [¹⁷⁷Lu]lutetium-dotatate (200 mCi) plus triapine (150 mg) dose was selected as the RP2D for the expansion phase. Grade ≥3 treatment related adverse events were observed in 77% patients: anemia (23%), nausea and vomiting (3% ), lymphopenia ( 58%), neutropenia ( 35%) and leukopenia ( 39%). The majority of cytopenias were transient and resolved within two weeks. Among the 28 evaluable patients, the objective response rate (ORR) was 21.4% and the median progression-free survival (mPFS) has not been reached (median follow-up period: 23.7 months). Conclusions: The combination of [¹⁷⁷Lu]lutetium-dotatate (200 mCi) and oral triapine (150 mg D1-14) was well tolerated and demonstrated preliminary activity in patients with well-differentiated GEP-NETs. (NCT04234568).

Abstract Background Neuroendocrine tumors (NETs) are rare, heterogeneous neoplasms associated with prolonged survival and substantial symptom burden. However, patient-reported outcomes across NET subtypes remain poorly characterized, particularly in real-world settings. This study describes baseline health-related quality of life (HRQoL) and care experiences among patients with gastroenteropancreatic and lung NETs, examining differences by tumor site and time since diagnosis. Methods The Neuroendocrine Tumors–Patient Reported Outcomes study is a prospective, multi-institutional US cohort of adults (aged 18 years and older) with incident small intestinal, pancreatic, gastroenteropancreatic, or lung NETs diagnosed from January 2018 through September 2024, identified via a validated electronic medical record–based computable phenotype. Baseline surveys assessed HRQoL, symptoms, care experiences, and clinical characteristics using validated instruments. Descriptive statistics and standardized mean differences compared responses by NET site and time since diagnosis. Results Among 2367 participants (mean age = 57.8 years; 57.3% female), 1974 had gastroenteropancreatic NETs (659 small intestinal NET, 555 pancreatic NET) and 393 had lung NETs. Fatigue (mean = 33.0), insomnia (mean = 32.5), and diarrhea (mean = 25.7) were the most burdensome symptoms. Lung NET patients reported worse dyspnea (standardized mean difference = 0.58, P < .001) and lower physical, role, and global QoL scores than those with gastroenteropancreatic NETs, while pancreatic NET patients reported better functioning. Diarrhea worsened over time, especially in small intestinal NETs. Most rated care highly (75.3%) but cited concerns about treatment side effects (80.4%), costs (60.7%), and travel burden (58.8%). Conclusions This large US cohort reveals persistent symptom burden and HRQoL variation by tumor site and disease duration, underscoring the need for longitudinal HRQoL assessment in NET care.

Abstract Introduction: Recruitment for rare disease studies is challenging due to small eligible populations. Traditional clinical research management systems often lack tools to track recruitment contacts prior to enrollment. The NET-PRO study, focused on neuroendocrine tumors (NETs), implemented a participation monitoring system to enhance recruitment efficiency and representativeness. Methods: NET-PRO is a multicenter cohort study of 2538 adults diagnosed with gastroenteropancreatic (GEP) or lung NETs between January 2018 and September 2024. Recruitment occurred from January 2022 to February 2025 across 14 U.S. medical centers. Sites used flexible recruitment methods (email, mail, phone, in-clinic) and tracked contacts using REDCap-based tools. Participant characteristics were analyzed by enrollment mode (online or mail) and recruitment difficulty (number of contacts required prior to enrollment) using standardized mean differences, chi-square tests, and ANOVA. Results: Of 9279 contacted patients, 2675 consented (28.8%) and 2538 enrolled (27.4%). Most enrolled online (83.2%), while 16.8% enrolled by mail. Mail respondents were older, had lower education and income, and more comorbidities. Among those enrolled, recruitment difficulty was associated with older age, lower education and income, but not comorbidity. Over half of the most difficult-to-recruit participants enrolled online. Contact methods varied by attempt, with email dominating early contacts and phone/mail used more in later attempts. Conclusions: A participation monitoring tool supported flexible, multimodal recruitment and improved sample representativeness in a rare cancer study. Tracking recruitment contacts enabled adaptive strategies and may reduce bias in observational research by enabling better outreach to harder-to-reach populations.

TPS646 Background: SSTR-targeted RPT has transformed the treatment landscape for NETs, significantly improving clinical outcomes in phase 3 studies versus other targeted therapies. Nevertheless, disease progression and renal toxicity after treatment highlight the need for further improvement. Use of the α-emitter 225 Ac as the radioactive component has shown promising results in clinical studies: initial data from ACTION-1 suggest promising efficacy for RYZ101, a first-in-class, highly potent α-emitting RPT, in patients with SSTR+ GEP-NETs progressing after 2–4 cycles of 177 Lu-somatostatin analogs. RYZ401 is a cyclic 6-amino acid SSTR-targeting peptide agonist conjugated to a DOTA chelator bound to 225 Ac. Preclinical data have shown an improved therapeutic window versus DOTATATE. RYZ401 has the potential to deliver higher radiation doses to tumors, with improved renal clearance and lower kidney absorbed dose, potentially eliminating the need for amino acid infusion. Methods: RYZ401-101 is a global, multicenter, phase 1, first-in-human, dose-escalation/-expansion study designed to determine the recommended phase 2 dose (RP2D) and optimal treatment regimen, safety and tolerability, and preliminary efficacy of RYZ401 in patients with NETs and other selected solid tumors expressing SSTRs. Key eligibility criteria: histologically confirmed metastatic or unresectable well-differentiated NETs; WHO grade 1–3 (Ki-67 ≤55%); ≥1 SSTR PET-positive measurable lesion; and disease progression after ≥1 prior treatment line. In dose escalation, 6–18 patients will receive escalating doses of RYZ401 (2.0–11.1 MBq IV Q6W × 2–4 cycles); no amino acid co-infusion is planned. In dose expansion, approximately 80 patients will receive RYZ401 at the RP2D, 40 patients with well-differentiated GEP-NETs (cohort A) and 40 with other SSTR+ tumors including non-GEP-NETs (cohort B). Primary endpoints: dose-limiting toxicities in weeks 1–4 of treatment (dose escalation) and safety (dose expansion). Secondary endpoints: safety, pharmacokinetics, and efficacy outcomes (dose escalation and expansion). RYZ401 dosimetry will be evaluated in a sub-study of 10−16 patients. Enrollment is ongoing in the USA. Clinical trial information: NCT07165132 .

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 .

PURPOSE To develop recommendations for systemic therapy for well-differentiated grade 1 (G1) to grade 3 (G3) metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs). METHODS ASCO convened an Expert Panel to conduct a systematic review of relevant studies and develop recommendations for clinical practice. RESULTS Eight randomized controlled trials met the inclusion criteria for the systematic review. RECOMMENDATIONS Somatostatin analogs (SSAs) are recommended as first-line systemic therapy for most patients with G1-grade 2 (G2) metastatic well-differentiated GI-NETs. Observation is an option for patients with low-volume or slow-growing disease without symptoms. After progression on SSAs, peptide receptor radionuclide therapy (PRRT) is recommended as systematic therapy for patients with somatostatin receptor (SSTR)–positive tumors. Everolimus is an alternative second-line therapy, particularly in nonfunctioning NETs and patients with SSTR-negative tumors. SSAs are standard first-line therapy for SSTR-positive pancreatic (pan)NETs. Rarely, observation may be appropriate for asymptomatic patients until progression. Second-line systemic options for panNETs include PRRT (for SSTR-positive tumors), cytotoxic chemotherapy, everolimus, or sunitinib. For SSTR-negative tumors, first-line therapy options are chemotherapy, everolimus, or sunitinib. There are insufficient data to recommend particular sequencing of therapies. Patients with G1-G2 high-volume disease, relatively high Ki-67 index, and/or symptoms related to tumor growth may benefit from early cytotoxic chemotherapy. For G3 GEP-NETs, systemic options for G1-G2 may be considered, although cytotoxic chemotherapy is likely the most effective option for patients with tumor-related symptoms, and SSAs are relatively ineffective. Qualifying statements are provided to assist with treatment choice. Multidisciplinary team management is recommended, along with shared decision making with patients, incorporating their values and preferences, potential benefits and harms, and other characteristics and circumstances, such as comorbidities, performance status, geographic location, and access to care. Additional information is available at www.asco.org/gastrointestinal-cancer-guidelines .

Abstract Introduction The CYP2D6 enzyme metabolizes opioids commonly prescribed for cancer‐related pain, and CYP2D6 polymorphisms may contribute to variability in opioid response. We evaluated the feasibility of implementing CYP2D6 ‐guided opioid prescribing for patients with cancer and reported pilot outcome data. Methods Adult patients from two cancer centers were prospectively enrolled into a hybrid implementation‐effectiveness clinical trial and randomized to CYP2D6 ‐genotype‐guided opioid selection, with clinical recommendations, or usual care. Implementation metrics, including provider response, medication changes consistent with recommendations, and patient‐reported pain and symptom scores at baseline and up to 8 weeks, were assessed. Results Most (87/114, 76%) patients approached for the study agreed to participate. Of 85 patients randomized, 71% were prescribed oxycodone at baseline. The median (range) time to receive CYP2D6 test results was 10 (3–37) days; 24% of patients had physicians acknowledge genotype results in a clinic note. Among patients with CYP2D6 ‐genotype‐guided recommendations to change therapy ( n = 11), 18% had a change congruent with recommendations. Among patients who completed baseline and follow‐up questionnaires ( n = 48), there was no difference in change in mean composite pain score (−1.01 ± 2.1 vs. −0.41 ± 2.5; p = 0.19) or symptom severity at last follow‐up (3.96 ± 2.18 vs. 3.47 ± 1.78; p = 0.63) between the usual care arm ( n = 26) and genotype‐guided arm ( n = 22), respectively. Conclusion Our study revealed high acceptance of pharmacogenetic testing as part of a clinical trial among patients with cancer pain. However, provider response to genotype‐guided recommendations was low, impacting assessment of pain‐related outcomes. Addressing barriers to utility of pharmacogenetics results and clinical recommendations will be critical for implementation success.

TPS4191 Background: Pheochromocytomas (PHEOs) and paragangliomas (PGLs) are rare neuroendocrine tumors (NETs) that arise from chromaffin cells. Few antitumor therapies have been developed for patients (pts) with advanced PHEO/PGLs (APP). Potent poly (ADP-ribose) polymerase (PARP) is activated after DNA damage and regulates base excision repair, homologous recombination and non-homologous end joining. Inhibition of PARP enzymatic activity blocks PARP-mediated DNA repair, therefore PARP inhibitors can be directly cytotoxic to tumor cells which then permits synergy with agents that increase prevalence of single-strand breaks in tumor models. Temozolomide (TMZ) is an alkylating agent that induces single-strand DNA breaks and therefore is an optimal therapeutic pair with a PARP inhibitor. We are conducting a phase II multi-institutional study to evaluate the antitumor activity of TMZ and olaparib [OLA (a PARP inhibitor)] in patients with APP. Methods: Patients with APP with radiographic evidence of disease progression by RECIST v1.1 in the 12 months prior to registration can be enrolled in this phase II randomized study. Patients will be randomized in a 2:1 allocation with more patients to Arm 1. Arm 1 will receive TMZ 75 mg/m2 daily and OLA 200 mg twice daily on days 1-7 of a 21-day cycle. Arm 2 will receive TMZ 200 mg/m2 daily on days 1-5 of a 28-day cycle. Treatment on Arm 1 will continue for 13 cycles, followed by OLA maintenance until disease progression. Treatment on Arm 2 will continue for 13 cycles or until disease progression. The primary objective is to compare the progression-free survival between the two arms with a planned interim analysis for futility. Secondary endpoints include safety, response rate, and overall survival. Correlative endpoints include biochemical response and biomolecular markers (germline succinyl dehydrogenase mutations and tumor status of the repair enzyme methylguanine-DNA methyltransferase). We anticipate a null PFS median of approximately 5.4 months. We plan to accrue a total of 76 patients (randomized at a rate of 2:1 with more patients enrolled to the TMZ+OLA arm) in 38 months with a minimum follow-up of 2.5 months to achieve 56 PFS events. This design includes one interim analysis for futility using Rho Family spending functions (Rho = 2.5) and will yield 89% power to detect a hazard ratio (HR) of 0.5 (median PFS of 5.4 vs. 10.8 months) assuming exponential survival and using a one-sided log-rank test with type I error rate of 0.11. Clinical trial information: NCT04394858 .

High-grade neuroendocrine neoplasms are a rare disease entity and account for approximately 10% of all neuroendocrine neoplasms. Because of their rarity, there is an overall lack of prospectively collected data available to advise practitioners as to how best to manage these patients. As a result, best practices are largely based on expert opinion. Recently, a distinction was made between well-differentiated high-grade (G3) neuroendocrine tumors and poorly differentiated neuroendocrine carcinomas, and with this, pathologic details, appropriate imaging practices and treatment have become more complex. In an effort to provide practitioners with the best guidance for the management of patients with high-grade neuroendocrine neoplasms of the gastrointestinal tract, pancreas, and gynecologic system, the North American Neuroendocrine Tumor Society convened a panel of experts to develop a set of recommendations and a treatment algorithm that may be used by practitioners for the care of these patients. Here, we provide consensus recommendations from the panel on pathology, imaging practices, management of localized disease, management of metastatic disease and surveillance and draw key distinctions as to the approach that should be utilized in patients with well-differentiated G3 neuroendocrine tumors vs poorly differentiated neuroendocrine carcinomas.