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Patients with cholangiocarcinoma have poor clinical outcomes due to late diagnoses, poor prognoses, and limited treatment strategies. To identify drug combinations for this disease, we have conducted a genome-wide CRISPR screen anchored on the bromodomain and extraterminal domain (BET) PROTAC degrader ARV825, from which we identified anticancer synergy when combined with genetic ablation of members of the mTOR pathway. This combination effect was validated using multiple pharmacological BET and mTOR inhibitors, accompanied by increased levels of apoptosis and cell cycle arrest. In a xenograft model, combined BET degradation and mTOR inhibition induced tumor regression. Mechanistically, the 2 inhibitor classes converged on H3K27ac-marked epigenetic suppression of the serine glycine one carbon (SGOC) metabolism pathway, including the key enzymes PHGDH and PSAT1. Knockdown of PSAT1 was sufficient to replicate synergy with single-agent inhibition of either BET or mTOR. Our results tie together epigenetic regulation, metabolism, and apoptosis induction as key therapeutic targets for further exploration in this underserved disease.

Background: Treatment of chronic lymphocytic leukemia (CLL) has been transformed with targeted therapies including inhibitors of Bruton's tyrosine kinase (BTKi). Currently three covalent BTK inhibitors (cBTKi) are approved for CLL, but most patients eventually relapse, commonly through acquisition of the C481S BTK mutation (Woyach et al. 2014). Pirtobrutinib and nemtabrutinib are non-covalent BTK inhibitors (ncBTKi) developed to target and inhibit C481S mutant BTK. However novel secondary site mutations in BTK, namely T474I and L528W, have been found to confer resistance to both cBTKi and ncBTKi (Wang et al. 2022). Regardless of these mutations, BCR signaling remains intact, suggesting that inhibition of BTK maintains its therapeutic importance. LP-168 is a novel ultra-selective 4 th generation BTKi with an active warhead capable of covalent interaction with WT BTK or non-covalent binding when a BTK C481 mutation is present. Methods: To determine the target selectivity of LP-168 we screened the compound against 468 kinases in the scanMAX Kinase Assay. For validation of covalent binding, dialysis against WT BTK was performed. Primary CLL B cells were isolated by negative selection and treated with LP-168 for all experiments. BCR signaling alterations were assessed via immunoblot to observe changes in target protein phosphorylation. Changes in CLL migration towards CXCL12 or CXCL13 were interrogated by transwell migration. Cytotoxicity towards primary CLL cells was measured via Annexin V/PI flow cytometry with and without HS-5 stromal cell support. Experiments using TMD8 cells were performed following CRISPR modification to insert WT, C481S, or T474I BTK. In vivo survival studies were performed using both the Eμ-TCL1 and Eμ-MTCP1 mouse engraftment models. Results: LP-168 demonstrated selectivity towards BTK with roughly 700-fold selectivity for BTK vs its next off-target. In an enzymatic assay, LP-168 displayed nanomolar potency towards both WT BTK (IC 50=0.11 nM) and C481S BTK (IC 50=1.0 nM). Following 2-hour drugging, LP-168 inhibited BCR signaling in primary CLL B cells at increasing concentrations, demonstrated by reduced phosphorylation of BTK (92%, p<0.0001, n=8) and its immediate downstream target PLCγ2 (41%, p=0.0013, n=8). Migration capacity of primary CLL cells towards CXCL12 and CXCL14 was also found to decrease after 2-hours of treatment with LP-168 (52%, p<0.001, n=10 and 51%, p<0.001, n=10, respectively). After 48 hours of exposure, LP-168 was able to induce cytotoxicity of primary CLL cells alone and in co-culture with HS-5 stromal cells in a dose-dependent manner, with similar or improved efficacy to other BTKi. LP-168 decreased CLL cell production of CCL3 and CCL4 chemokines (CCL3: 93%, p<0.001, n=8; CCL4: 93%, p<0.001, n=8). LP-168 also demonstrated modest cytotoxicity towards TMD8 cells harboring either C481S BTK (24%, p=0.0008 , n=3) or T474I BTK (13%, p=0.0690, n=3), as well as decreased production of CCL3 (C481S: 95%, p<0.0001, n=3; T474I: 99%, p<0.0001, n=3) and CCL4 (C481S: 97%, p<0.0001, n=3; T474I: 98%, p<0.0001, n=3) (Figure 1A). Further, we observed inhibition of downstream BCR signaling in primary CLL B cells harboring C481S via immunoblotting and cytokine production. Finally, to evaluate the in vivo efficacy of LP-168 we tested this compound in both the Eµ-TCL1 and Eµ-MTCP1 models. We treated mice daily via oral gavage and found that 50 mg/kg of LP-168 significantly improved survival in the Eµ-TCL1 model when compared to vehicle (median 51 vs 44 days; p=0.0018) or ibrutinib at 50 mg/kg (median 51 vs 45 days; p=0.0098) and the Eµ-MTCP1 model when compared with vehicle (median 122 vs 62 days; p<0.0001) or ibrutinib at 50 mg/kg (median 122 vs 96 days; p=0.0162) (Figure 1B). Conclusions: Collectively, our data demonstrate that LP-168 is a potent and selective inhibitor of BTK with activity against CLL, even in the presence of mutations that mediate resistance to cBTKi and ncBTKi. These data support the continued preclinical and clinical investigation of LP-168, which is currently being studied in the phase 1 setting of CLL (NCT04775745) and NHL (NCT04993690).

The scarcity of liver grafts has prompted developments in living donor liver transplantations (LDLT), with previous literature illustrating similar outcomes in recipients compared to deceased donor transplants. However, significant concerns regarding living donor morbidity and mortality have yet to be examined comprehensively. This study aims to provide estimates of the incidence of various outcomes in living liver donors. In this meta-analysis, Medline and Embase were searched from inception to July 2022 for articles assessing the incidence of outcomes in LDLT donors. Complications in the included studies were classified into respective organ systems. Analysis of incidence was conducted using a generalized linear mixed model with Clopper-Pearson intervals. Eighty-seven articles involving 60,829 living liver donors were included. The overall pooled incidence of complications in LDLT donors was 24.7% (CI: 21.6%–28.1%). The incidence of minor complications was 17.3% (CI: 14.7%–20.3%), while the incidence of major complications was lower at 5.5% (CI: 4.5%–6.7%). The overall incidence of donor mortality was 0.06% (CI: 0.0%–0.1%) in 49,027 individuals. Psychological complications (7.6%, CI: 4.9%–11.5%) were the most common among LDLT donors, followed by wound-related (5.2%, CI: 4.4%–6.2%) and respiratory complications (4.9%, CI: 3.8%–6.3%). Conversely, cardiovascular complications had the lowest incidence among the subgroups at 0.8% (CI: 0.4%–1.3%). This study presents the incidence of post-LDLT outcomes in living liver donors, illustrating significant psychological, wound-related, and respiratory complications. While significant advancements in recent decades have contributed towards decreased morbidity in living donors, our findings call for targeted measures and continued efforts to ensure the safety and quality of life of liver donors post-LDLT.

Abstract Introduction: First pass effect (FPE), achievement of complete recanalization (mTICI 2c/3) with a single pass, is a significant predictor of favorable outcomes for endovascular treatment (EVT) in large vessel occlusion stroke (LVO). However, data concerning the impact on functional outcomes and predictors of FPE in medium vessel occlusions (MeVO) are scarce. Patients and Methods: We conducted an international retrospective study on MeVO cases. Multivariable logistic modeling was used to establish independent predictors of FPE. Clinical and safety outcomes were compared between the two study groups (FPE vs non-FPE) using logistic regression models. Good outcome was defined as modified Rankin Scale 0–2 at 3 months. Results: Eight hundred thirty-six patients with a final mTICI ⩾ 2b were included in this analysis. FPE was observed in 302 patients (36.1%). In multivariable analysis, hypertension (aOR 1.55, 95% CI 1.10–2.20) and lower baseline NIHSS score (aOR 0.95, 95% CI 0.93–0.97) were independently associated with an FPE. Good outcomes were more common in the FPE versus non-FPE group (72.8% vs 52.8%), and FPE was independently associated with favorable outcome (aOR 2.20, 95% CI 1.59–3.05). 90-day mortality and intracranial hemorrhage (ICH) were significantly lower in the FPE group, 0.43 (95% CI, 0.25–0.72) and 0.55 (95% CI, 0.39–0.77), respectively. Conclusion: Over 2/3 of patients with MeVOs and FPE in our cohort had a favorable outcome at 90 days. FPE is independently associated with favorable outcomes, it may reduce the risk of any intracranial hemorrhage, and 3-month mortality.

370 Background: Mounting evidence suggests tailored preparation targeting geriatric vulnerabilities can improve functional outcomes after major surgery in older adults. Although many surgeons express interest in surgical optimization of older patients, few practices have the time or expertise to deliver geriatric prehabilitation before surgery. This study investigated the effectiveness of OPTI-Surg, a frailty prehabilitation toolkit, for improving surgical outcomes. In this abstract, we report adherence to the OPTI-Surg toolkit in the intervention arm. Methods: Thoracic (T), gastrointestinal (GI), and urologic (GU) oncological surgery practices affiliated with NCI’s Community Oncology Research Program (NCORP) were randomized 1:1:1, stratified by practice type, to usual care (control), OPTI-Surg toolkit, or OPTI-Surg with an implementation coach. The toolkit was implemented at the practice level and consisted of the 12-item Edmonton Frail Scale (EFS) and guided recommendations for interventions including referrals directed at identified vulnerabilities. Eligible patients were ≥70 years old and undergoing curative intent surgery for T, Gl, or GU cancers. Results: From July 2019 to October 2021, 155 patients were enrolled in the OPTI-Surg intervention arm. The EFS was administered to 153 (98.7%) of the enrolled patients, 143 of whom went on to have surgery. Overall, 134 (93.7%) surgical patients had at least one deficit identified on the EFS assessment and 55 (41.0%) of these patients received a recommended referral intended to optimize surgical outcomes. Among the 55 patients who received referrals, 44 (80.0%) followed through on the referral. Individual deficit rates were highest for medication use, general health status, and functional performance, and referrals were most frequently made for deficits in continence and functional independence (Table). Conclusions: In the OPTI-Surg geriatric surgical optimization trial, implementation of the frailty screening with the EFS assessment was successful. Rates of recommended referrals for patients with identified deficits, however, were low. When referred, most patients followed through for targeted prehabilitation. Clinical trial information: NCT03857620 .[Table: see text]

314 Background: In a recent trial, we observed no statistically significant increase in engagement after a web-based decision aid (DA) was delivered to breast cancer patients prior to a surgical consult. However, a minority of the intervention group (44%) reviewed the DA. The objective is to assess the effect of the DA on engagement for the cohort of patients who reviewed it. Methods: A stepped wedge trial was conducted with 10 NCI Community Oncology Research Program clinics that care for a high proportion of socioeconomically disadvantaged patients (6/2019-12/2021). Clinics were randomized to time of transition from usual care (UC) to delivery of a DA. Patients with stage 0-3 breast cancer eligible for surgery provided consent prior to a surgical consult. Engagement was measured from audio-recorded surgical consults (Active Patient Behaviors, Street protocol). For this analysis, we identified a cohort of treatment compliant (TC) patients who reviewed the DA. Intervention effects comparing TC and UC groups were tested with linear mixed-effects models, accounting for time, enrollment post-COVID, and patient age, race, education, and socioeconomic disadvantage (assessed with Area Deprivation Index and dichotomized). Exploratory models were generated using Active Patient Behavior subcomponents (asking questions, assertive responses, expressions of concern) as the outcome. Results: The cohort includes 407 patients (UC 264; TC 143). TC patients were more likely to be white (TC 73%, UC 64%, p=0.03), have a college degree (TC 65%, UC 55%, p=0.05), and not be disadvantaged (TC 89%, UC 72%, p=0.001). TC was associated with increased engagement (8.2 [0.08, 16.2], p=0.048, Table). A college degree was associated with higher, while black race and socioeconomic disadvantage lower, engagement. On exploratory analyses, TC had a stronger association with higher levels of assertive responses (2.9 [-0.3, 6.1], p=0.07) compared with asking questions (5.2 [-1.4, 11.9], p=0.12) or expressions of concern (0.08 [-0.60, 0.76], p=0.82). Conclusions: We observed increased engagement in breast cancer patients who reviewed a DA prior to a surgical consult. However, we also observed differences based on race, education, and socioeconomic disadvantage. Further research will identify adjunct interventions to combine with the DA to improve cancer care delivery for diverse populations. Support: UG1 CA189823; AHRQ R01HS025194; https://acknowledgments.alliancefound.org. Clinical trial information: NCT03766009 .[Table: see text]