Armstrong, Andrew J.

57 Background: Cardiovascular disease (CVD) is the leading non-cancer cause of death among men with prostate cancer (PC), particularly during androgen-deprivation therapy. While CVD risk-prediction models are well established in the general population, barriers to integration within oncology workflows remain poorly defined. Guided by the PRISM and RE-AIM frameworks, this study evaluated multilevel determinants influencing adoption, feasibility, and sustainability of CVD risk-assessment tools in PC care. Methods: A national, cross-sectional survey of 45 physicians (medical oncology 49%, urology 38%, radiation oncology 13%) from 18 U.S. states was conducted. Respondents represented early- (27%), mid- (36%), and late-career (38%) clinicians across academic (87%) and community (13%) settings. Quantitative items mapped to PRISM/RE-AIM domains assessed adaptability, cost/resource feasibility, effectiveness, equity, and sustainability; open-ended responses explored contextual barriers and facilitators. Descriptive statistics summarized quantitative data. Results: Physicians reported moderate-to-high readiness to adopt a CVD risk-assessment tool, emphasizing workflow alignment and EHR integration over algorithmic complexity. Table 1 summarizes domain-specific findings. Ninety-three percent of respondents favored lab-independent models that minimize workflow disruption. Conclusions: Pre-implementation analysis highlighted that structural barriers, rather than algorithmic or statistical limitations, remain the primary obstacles to adopting CVD risk-assessment tools in prostate-cancer care. Physicians emphasized the need for EHR-integrated, non-laboratory-based, and time-efficient tools that align with routine oncology workflows and minimize cross-specialty friction. Addressing these practical and organizational determinants may be pivotal to achieving equitable, scalable, and sustainable cardio-oncology implementation across diverse practice settings. PRISM and RE-AIM constructs evaluation results. Construct Likely/Very Likely (%) Interpretation Perceived Effectiveness 87% Broad confidence in clinical utility Equity in Patient Reach 75% Strong perceived equity in reach Equity in Effectiveness 73% Expected to perform consistently across populations Adaptability to Workflow 71% High compatibility with existing clinic workflows Cost/Resource Feasibility 65% Feasible for resource-constrained settings Likelihood of Adoption 60% Moderate readiness for implementation Equity in Adoption 58% Equitable uptake possible despite resource differences Reach to Target Population 57% Moderate likelihood of reaching most patients Sustainability Over Time 51% Moderate long-term feasibility Consistency of Implementation 42% Need for standardized protocols

TPS276 Background: Metastatic castration-resistant prostate cancer (mCRPC) can evolve into a neuroendocrine-like subtype with aggressive behavior and poor outcomes (1). Nuclear Receptor-Binding SET Domain Protein 2 (NSD2) is overexpressed in prostate cancer and is a driver of both androgen-receptor (AR)-dependent signaling and of neuroendocrine differentiation, where cancer cells lose AR dependence and response to AR pathway inhibitors (ARPIs) (2,3,4). In studies of patient-derived neuroendocrine prostate cancer (NEPC) models, genetic depletion of NSD2 led to restoration of AR expression, reversal of adeno-to-neuroendocrine differentiation, and re-sensitization to ARPI (4). We hypothesize that NSD2 inhibition can reverse resistance to ARPIs in patients with progressive mCRPC, including with neuroendocrine differentiation. KTX-2001 is an oral, potent and selective small molecule inhibitor of NSD2. It is the sponsor’s second NSD2 inhibitor to enter the clinic. The sponsor’s first in class NSD2 inhibitor, KTX-1001, was shown to be tolerable and have preliminary efficacy in patients with relapsed/refractory multiple myeloma (5). Methods: STRIKE-001 (NCT07103018) is a multicenter, open-label phase 1 dose escalation trial of KTX-2001 monotherapy (Part A) and KTX-2001 + darolutamide (Part B). Key inclusion criteria are males age ≥18 years with mCRPC, progression after receiving ARPI, Eastern Cooperative Oncology Group performance score of 0-1, willingness to undergo biopsy if safe and feasible, and life expectancy of ≥6 months. Participants take KTX-2001 by mouth once daily alone (Part A) or with darolutamide 600 mg twice daily (Part B). Dose escalation of KTX-2001 in Parts A and B will follow a 3+3 design and occur in parallel at multiple planned dose levels. Primary objectives are to assess the safety and tolerability, determine MTD, and determine RP2D(s) for further study of KTX-2001 alone and in combination with darolutamide. Secondary objectives include characterization of efficacy and PK parameters for both KTX-2001 monotherapy and in combination with darolutamide. Exploratory objectives include study of pharmacodynamic effects, circulating tumor cells, and cell-free DNA. 1. Conteduca V, Eur J Cancer 2019. 2. Parolia A, Nat Genet 2024. 3. Aytes A, Nat Commun 2018 4. Li J, bioRxiv 2023.07.18.549585 5. Bories P, Blood Vol 144, Suppl 1,2024. Clinical trial information: NCT07103018 .