Citations

Background: TITIN truncational variants (TTNtv) is the predominant genetic factor for dilated cardiomyopathy (DCM). Therapeutic development for TTNtv DCM has been confounded by allelic heterogeneity (AH), i.e. while truncations in the C-terminal A-domain (TTNtv-As) are pathogenic, truncations in the N-terminal Z-disc domain (TTNtv-Zs) are largely benign. Molecular mechanisms underlying AH remain elusive, partially because of the lack of an in vivo animal model. Objective: We enquire whether zebrafish is a faithful vertebrate model for deciphering AH in TTNtv DCM and for therapeutic development. Methods and Results: Through comparing phenotypes among a series of ttntv -As and ttntv -Zs in adult zebrafish, we detected DCM-like phenotypes only in ttntv -As but not ttntv -Zs. Similar to human TTNtv DCM and corresponding rodent models, zebrafish ttntv -As manifest decreased ejection fraction, enlarged heart size, myofibril dys-organization, compromised exercise capacity, and dysregulated autophagy. Moreover, we noted exaggerated cardiac senescence at the later stage of the pathogenesis of ttntv DCM. Because AH in autophagy dysregulation was also detected in homozygous ttntv-A zebrafish embryos, we screened autophagy genes and identified ulk1 inhibition that is able to repair the dysregulated autophagy. A similar repairing effect of ulk1 inhibition on dysregulated autophagy was noted in an adult heterozygous ttntv-A model, which is sufficient to attenuate the cardiac senescence and improve cardiac function. Conclusion: Our data suggested adult zebrafish as the first vertebrate model that is able to recapitulate AH in TTNtv DCM patients. Conserved phenotypes including autophagy dysregulation are recapitulated in this lower vertebrate model, while cardiac senescence has been suggested as a novel pathological event. Genetic studies in this animal strongly suggest that repairing autophagy dysregulation is a therapeutic avenue for TTNtv DCM, and identified ulk1 as a candidate therapeutic target gene.

Abstract Background and Aims The use of multiple markers may improve the accuracy in glomerular filtration rate (GFR) estimation especially when the interpretation of creatinine and cystatin C is limited. We sought to externally validate a recently developed multi-marker nuclear magnetic resonance (NMR)-based estimated GFR equation (eGFR-NMR) using the biracial Genetic Epidemiology Network of Arteriopathy cohort. Method We included 224 sex, race/ethnicity, and mGFR-category-matched participants. GFR was measured using urinary clearance of iothalamate (mGFR). We calculated eGFR-NMR using serum creatinine, valine, myo-inositol, and cystatin C, age, and sex. We compared the reliability of eGFR-NMR with current eGFR equations (2021 Chronic Kidney Disease Epidemiology Collaboration equations for creatinine [eGFR-Cr] and creatinine with cystatin C [eGFR-Cr-CysC]) using median bias, precision, and accuracy metrics. In particular, we evaluated its performance in age, sex, and race subgroups. Results In the overall cohort, mean age was 63 (±8) years, 54% were females, 49% were Black individuals, and mean mGFR was 78.7 (±24.3) ml/min/1.73 m2. eGFR-NMR overestimated mGFR by 2 mL/min/1.73 m2 (95% CI, 4 to 0.7) while eGFR-Cr-CysC underestimated mGFR by −5 mL/min/1.73 m2 (95% CI, −2 to −7). All equations had acceptable accuracy metrics. When stratified by age, sex, and race, eGFR-NMR performed the best among Black males age <65 years compared to current equations (Figure 1). In this subgroup, eGFR-NMR was unbiased (bias, 2mL/min/1.73 m2 [95% CI, -3 to 10]) compared to substantial biases of eGFR-Cr (bias, 17 mL/min/1.73 m2 [95% CI, 9 to 24]) and eGFR-Cr-CysC (bias, 15 mL/min/1.73 m2 [95% CI, 6 to 20]). In other subgroups, measures of accuracy for eGFR-NMR, eGFR-Cr, eGFR-Cr-CysC were generally similar. Conclusion eGFR-NMR can be used to estimate mGFR and was more accurate than CKD-EPI equations among Black males age <65 years.

Abstract Enhanced DNA repair is an important mechanism of inherent and acquired resistance to DNA targeted therapies, including poly ADP ribose polymerase inhibition. Spleen associated tyrosine kinase (Syk) is a non-receptor tyrosine kinase known to regulate immune cell function, cell adhesion, and vascular development. Here, we report that Syk can be expressed in high grade serous ovarian cancer and triple negative breast cancers and promotes DNA double strand break resection, homologous recombination (HR) and therapeutic resistance. We found that Syk is activated by ATM following DNA damage and is recruited to DNA double strand breaks by NBS1. Once at the break site, Syk phosphorylates CtIP, a key mediator of resection and HR, at Thr-847 to promote repair activity, specifically in Syk expressing cancer cells. Syk inhibition or genetic deletion abolished CtIP Thr-847 phosphorylation and overcame the resistant phenotype. Collectively, our findings suggest that Syk drives therapeutic resistance by promoting DNA resection and HR through a novel ATM-Syk-CtIP pathway, and that Syk is a new tumor-specific target to sensitize Syk-expressing tumors to PARPi and other DNA targeted therapy.

Abstract Introduction Cigarette smoking is highly prevalent among Asian American immigrant subgroups. Previously, Asian-language telephone Quitline services were only available in California. In 2012, the Centers for Disease Control and Prevention (CDC) funded the national Asian Smokers’ Quitline (ASQ) to expand Asian-language Quitline services nationally. However, there are relatively few calls to the ASQ from outside California. Aims and Methods This pilot study assessed the feasibility of two proactive outreach interventions to connect Vietnamese-speaking participants who smoke to the ASQ. Both interventions, (1) proactive telephone outreach with a counselor trained in motivational interviewing (PRO-MI) and (2) proactive telephone outreach with interactive voice response (PRO-IVR), were adapted to be culturally and linguistically appropriate for Vietnamese-speaking participants. Participants were randomly assigned 2:1 to PRO-IVR versus PRO-MI. Assessments were conducted at baseline and 3 months post-enrollment. Feasibility indicators were the recruitment rate and initiation of ASQ treatment. Results Using the HealthPartners electronic health record, a large health system in Minnesota, we identified approximately 343 potentially eligible Vietnamese participants who were mailed invitation letters and baseline surveys with telephone follow-up. We enrolled 86 eligible participants (25% recruitment rate). In the PRO-IVR group 7/58 participants were directly transferred to the ASQ (12% initiation rate) and in the PRO-MI group 8/28 participants were warm transferred to the ASQ (29% initiation rate). Conclusions This pilot study demonstrates the feasibility of our recruitment methods and of implementing proactive outreach interventions to promote the initiation of smoking cessation treatment with the ASQ. Implications This pilot study contributes novel data on the uptake of Asian Smokers’ Quitline (ASQ) services among Vietnamese-speaking people who smoke (PWS) with two proactive outreach interventions: (1) proactive telephone outreach with a counselor trained in motivational interviewing (PRO-MI) and (2) proactive telephone outreach with interactive voice response (PRO-IVR). We found that it is feasible to implement these proactive outreach interventions to promote the initiation of ASQ cessation treatment among Vietnamese-language speaking PWS. Future large trials are needed to rigorously compare PRO-MI and PRO-IVR and conduct budget impact analyses to understand the most efficient strategies for incorporation into health system settings.

Injection of A-MSC-derived EVs harvested from patients who are lean can resolve myocardial injury in mice with experimental renovascular hypertension more effectively than A-MSC-derived EVs from patients with obesity. These observations underscore and might have important ramifications for the self-healing capacity of patients with obesity and for the use of autologous EVs as a regenerative tool.

e22514 Background: Several colorectal cancer (CRC) screening tests, shown to reduce CRC incidence and mortality, are recommended for average-risk adults aged 45-75 years. CRC screening is underutilized in the US with access to facility-based options, such as colonoscopy, representing a barrier to screening. Stool-based tests are guideline-endorsed and offer patients a convenient and more accessible CRC screening option that can be completed at home. Provider recommendation is consistently identified as the primary factor driving patient adherence. Understanding how aspects of patient-provider communication influence CRC screening can inform interventions to improve adherence. We developed a survey, informed by behavioral theory, to identify communication factors associated with completion of mt-sDNA screening. Methods: Adults aged 45-75 years, with a US postal address, who received a valid order for mt-sDNA and whose kit was shipped between 5/21-9/21 were eligible for sampling. The survey was administered by RTI International between 3/22-6/22. Participants could complete electronic or paper surveys. We fit a multivariable logistic regression to identify patient-provider communication factors associated with mt-sDNA test completion. Results: 2,973 respondents completed the survey (response rate = 21.7%). The majority (77.3%) completed the mt-sDNA test and said they would be ‘very likely’ (76.8%) to complete Cologuard in the future. The proportion of respondents who had conversations with their healthcare provider about Cologuard, and the specific content of those conversations, was significantly different between completers and non-completers and between respondents who said they were ‘very likely’ to complete Cologuard in the future compared to respondents who were not. Results from a binary logistic regression suggested that discussions with a healthcare provider related to step-by-step instructions for completing Cologuard (OR = 1.62) and needing to have a colonoscopy follow-up (OR = 1.93), as well as feeling included ‘a great deal’ in the decision-process with respondents’ healthcare provider (compared to ‘somewhat’ or ‘not at all’) increase the odds of kit completion. Additionally, healthcare provider discussions relating to test cost (OR = 1.47) and performance (OR = 1.72), as well as feeling included ‘a great deal’ in the decision-process was positively associated with respondents indicating they were ‘very likely’ to use Cologuard in the future. Provider discussions about the cost of a follow-up colonoscopy was negatively associated with a ‘very likely’ future user (OR = 0.52). Conclusions: Healthcare providers play a key role in patient adherence to CRC screening and must be appropriately prepared and resourced to educate and to engage patients in shared decision-making about CRC screening.

e21118 Background: Leptomeningeal metastasis (LM) is a debilitating condition associated with advanced non-small cell lung cancer (NSCLC). When driver mutations in the epidermal growth factor receptor (EGFR) are identified, targeted therapies (TT) represent an appealing therapeutic strategy. However, the efficacy of TT for LM is unknown as LM patients are routinely omitted from clinical trials. Methods: We conducted a systematic review and meta-analysis of individual patient data to evaluate the efficacy of EGFR TT in EGFR-mutant NSCLC LM in accordance with PRISMA guidelines. EGFR-TTs evaluated were erlotinib, gefitinib, icotinib, afatinib, dacomitinib, osimertinib, zorifertinib, and furmonertinib. The co-primary endpoints were progression-free survival (PFS) and overall survival (OS). To assess differences between groups, shared frailty Cox regression models were used to estimate the hazard ratio (HR), 95% confidence interval (CI) and p-value. Results: 7780 abstracts were screened, identifying 126 publications with 232 patients, corresponding to 272 lines of EGFR-TT for NSCLC LM which met inclusion criteria. The overall median PFS (mPFS) in patients receiving any EGFR-TT was 9.15 months and the median overall survival was 14.5 months. In univariable analyses, osimertinib was associated prolonged PFS compared to other EGFR-TT, (mPFS of 11 versus 8 months, HR = 0.64; 95% CI: 0.44-0.93; P = 0.02). Osimertinib was numerically associated with prolonged OS compared to other EGFR-TT (mOS 16.8 months versus 13.6 months, HR = 0.72; 95% CI 0.44-1.17, P = 0.188). In multivariable analyses, ECOG performance status > 2 was independently associated with shortened PFS (mPFS 10 versus 8 months, HR = 1.54, 95% CI: 1.26-3.04; P < 0.05) and OS (mOS 16.5 versus 10 months, HR = 3.33, 95% CI: 1.80-6.18; P < 0.05). Conclusions: In the largest cohort of NSCLC LM treated with EGFR TT compiled to date, osimertinib is associated with marginally improved outcomes compared to other EGFR TTs. ECOG performance status is an independent predictor of prognosis in these patients. These results highlight the need for prospective studies for this difficult to treat patient population.

9093 Background: Pembrolizumab interrupts PD-1/-L1 interaction and is efficacious in many cancers. However, resistance invariably emerges in the majority of patients. Potential mechanisms include activation of compensatory pathways. The inhibition of sonic hedgehog signaling (sHH) was previously shown to induce intra-tumoral (IT) infiltration by CD4+, CD8+ and HLA-DR class II cells. Our preclinical data showed sHH inhibitor enhanced IT penetration by monoclonal antibodies and induced PD-L1 expression. We conducted a phase I study using a novel sequential pulse dosing of sonedegib followed by pembrolizumab in aST with an expansion cohort to determine the maximum tolerated dose (MTD), tolerability and preliminary efficacy. Methods: The dose escalation utilized a 3+3 design to determine the MTD and proceeded to expansion cohort upon determination of the MTD. Patients enrolled to each dose level were observed for dose limiting toxicities (DLTs) during the 1st cycle. The expansion cohort consisted of NSCLC and head/neck squamous cell carcinoma (HNSCC) previously treated by anti-PD1/-L1. The recommended phase 2 dose (RP2D) was determined following the review of the toxicity profile of the combination from all cycles. The study treatment consisted of sonidegib oral daily from day 1 to 8 and pembrolizumab I.V. 200 mg on day 8 on an every 3-week cycle. The sonidegib dose levels explored were 400, 600 and 800 mg. Archival tumor and blood specimens were collected for correlative studies. Adverse events (AEs) were categorized and graded per CTCAE v5.0, and tumor response by RECIST v1.1. Results: The study enrolled a total of 33 patients and 29 received treatment (13 in escalation and 16 in expansion), including patients with NSCLC, HNSCC, skin cancer, gastric cancer and melanoma. The enrollment to the NSCLC cohort is complete and HNSCC continues. No DLT was encountered during dose escalation and the MTD was not reached. The highest planned dose level was selected to proceed to expansion (sonidegib 800mg days 1-8 in combination with pembrolizumab I.V. 200 mg on day 8 on an every 3-week cycle). The expansion cohort proceeded to enroll 15 patients evaluable for AEs (10 NSCLC and 5 HSNCC). Grade 3 and above treatment-related AEs across all patients were hyperglycemia, fatigue, dyspepsia, abdominal pain. The mature efficacy data will be reported at the meeting. Conclusions: The study successfully determined the RP2D of sonidegib when dosed sequentially with pembrolizumab in advanced solid tumors. The AE profile of the combination is similar to that for respective agents given individually. The efficacy data among anti-PD1/-PDL1-treated NSCLC will be reported at the meeting. Clinical trial information: NCT04007744 .

3595 Background: PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine containing 12 immunogenic epitopes derived from 7 tumor-specific antigens frequently expressed in patients with mCRC. Following early evidence of clinical activity of PolyPEPI1018 in first-line MSS mCRC, here we report the results of a phase Ib study of PolyPEPI1018 vaccine plus trifluridine/tipiracil (TAS-102) in late-stage mCRC patients. Methods: Patients with MSS mCRC who have progressed on ≤2 lines of prior chemotherapy regimen for mCRC received PolyPEPI1018 subcutaneously on days 1 and 15 and TAS-102 orally twice daily on days 1-5 and 8-15 of a 28-day cycle. Treatment continued for up to 7 cycles, until disease progression or unacceptable toxicity. Immunomonitoring was performed at both blood and tumor levels prior to and on study treatment. The primary endpoint of the study was safety and tolerability. Data on objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and correlation studies will be presented. Results: 15 patients started treatment. Median age was 55 years (range 31–71), 73% had liver metastases (mets), 73% had KRAS mutant tumors. The most common side effect related to PolyPEPI1018 was Grade (Gr) 1-2 local skin reactions in 93% of patients. Gr 3 events (n = 15) at least possibly related to treatment were fatigue, decreased white blood cell, lymphocyte and neutrophil counts, nausea, diarrhea, myalgia, and maculo-papular rash. There were no Gr 4 or 5 events. The ORR was 0%. The DCR was 53.3% in the overall population and 36% and 100% for the patients with liver mets and without liver mets, respectively. The mPFS was 4 months (95%CI 2.2-6.1) in the overall population and 2.3 months (95%CI 2.1-NE) and 7.6 months (95%CI 4.4-NE) for the patients with liver mets and without liver mets, respectively (HR = 5.73 (95%CI 1.21, 27.06); p = 0.015). At the data cut-off date (Feb 10, 2023), the mOS was 8.7 months (95%CI 6.9-NE; not mature) in the overall population and it was not reached in patients without liver mets. Patients with increased PFS (≥ 24 weeks) had more robust vaccine-specific humoral and T cell responses induced by higher number of vaccine peptides than patients with PFS < 24 weeks. Conclusions: To our knowledge, this is the first study investigating combination of a cancer vaccine with TAS-102 chemotherapy in advanced MSS mCRC. Our results show that PolyPEPI1018 plus TAS-102 was well-tolerated with few grade 3 AEs beyond what is expected with TAS-102 monotherapy. Despite no objective tumor responses could be detected, correlative data suggest contribution of PolyPEPI1018-induced immunological responses to the improved clinical benefit and the combination warrants further testing. Clinical trial information: NCT05130060 .