66 Background: The FirstSight CRC screening blood test was previously shown to have sensitivities of 92.1% and 54.5% for CRC and AA at a specificity of 90.6% for 1,038 subjects from 18 clinical sites. In this report, we describe the independent external validation of the predefined FirstSight CRC screening blood test with new subjects from 16 sites dispersed across the US, 4 of which are new and did not participate in the previous study. Methods: The validation study included subjects from two sources: Average-risk, asymptomatic screening subjects from screening clinics supplemented with diseased-only subjects from surgical oncology centers. Blood was drawn before bowel prep for colonoscopy or treatment. External validation as well as Monte Carlo cross-validation (MCCV) methods were used to evaluate the performance of the pre-defined FirstSight assay, algorithm, and clinical thresholds in this independent external validation set. Results include sensitivity and specificity to detect CRC and AA and 95% confidence intervals. Results: The study cohort (55.2% female; mean age 56.9 yrs.) consisted of 449 subjects (White 61.7%; Black 14.5%; Hispanic 18%; AAPI and Middle Easterners 5.8%). The majority of them, 376 (84%), were asymptomatic, average-risk screening subjects (including 1 CRC, 53 AA, and all 322 negative subjects). An additional 73 (16%) diseased subjects (39 CRC and 34 AA) were enriched due to low disease prevalence. The FirstSight algorithm derives a test score from 0 to 100 as a quantitative measure of AA and CRC risk with a cutpoint to assign a binary low- or high-risk designation. The previously described cutpoint of 47.2 yielded a test specificity of 90.0%, and 90.0% and 52.9% sensitivity for the detection of CRC and AA, respectively. Here we report a higher cutpoint 50 with identical sensitivities but improved specificity to 90.7%. Point estimates of sensitivity and specificity, including CRC staging, and Clopper-Pearson exact 95% confidence intervals based on the external validation results are presented below. Conclusions: An external validation included 449 subjects from a multi-site, majority average-risk CRC screening study successfully validated the FirstSight Blood Test’s high performance as previously established with 1,038 subjects. The results bring forth confidence in the Test’s reproducibility in a large-scale clinical trial. Clinical trial information: NCT05127096 . [Table: see text]

75 Background: The National Polyp Study and 2021 USPSTF CRC-update highlight that the detection and removal of precancerous advanced adenomas (AA) prevents colorectal cancer (CRC), decreases mortality, and leads to higher cost savings than early cancer detection. Performance of a multimodal blood-based test for the detection of CRC and AA that integrates sensitive and accurate detection of circulating gastrointestinal epithelial cells and somatic oncologic variants as well as SEER data of the impact of sex and age is described. Methods: The prospective study included average-risk, asymptomatic screening subjects from 18 geographically dispersed US colonoscopy centers with blood drawn before colonoscopy. Monte Carlo cross-validation (MCCV) methods were used to evaluate the robustness of test performance through 2000 iterations of independent training and validation using bootstrap resampling with stratification to balance patient histopathology, age, and gender. Results include point estimates, confidence intervals, and distributions of sensitivity and specificity to detect AA and CRC. Results: The study cohort (53.2% female; mean age 56.7 yrs.) consisted of 1,038 subjects (White 65.1%; Black 8.5%; Hispanic 24.8%; Asian 1.7%); of which 954 (92%) were asymptomatic, average-risk screening subjects without age enrichment (including 11 CRC and 93 AA) and 84 (8%) were enriched case-control (65 CRC and 19 AA) subjects. The algorithm derives a test score from 0 (low risk) to 100 (high risk) as a quantitative measure of AA and CRC risk. A pre-defined cut point of 47.2 yields a test specificity > 90%, and 92.1% and 54.5% sensitivity for the detection of CRC and AA, respectively. Estimated sensitivities and selected Clopper-Pearson (Exact) 95% confidence intervals based on validation results from MCCV are presented. A split analysis shows for the 954 intended-use, asymptomatic, average-risk screening subjects, the sensitivity for CRC and AA are 100% and 55.9%. Conclusions: A multi-site, prospective, average-risk CRC screening study using a multimodal assay had high sensitivity and specificity for AA and CRC. The quantitative correlation of test scores with disease pathology indicates that the modes of the assay interrogate the primary underlying pathophysiology of disease. The results demonstrate the potential of this novel test to meet the clinically unmet need for a noninvasive strategy for CRC screening and prevention that detects CRC and AA. Clinical trial information: NCT05127096 . [Table: see text]

e15527 Background: Multimodal diagnostic classifiers survey signals from multiple biological compartments and provide iterative, independent and interactive information. Detection of both CRC and AA is critical for noninvasive colorectal screening to improve overall survival and prevent the 2.5-5% annual transition of AA to CRC. FirstSight integrates clinically validated somatic variants from cfDNA and circulating epithelial cells (CECs) adjusting for age and sex. CECs provide information from both intrinsic factors of the adenoma and extrinsic factors such as adenoma microenvironment which facilitates early systemic entry. We sought to assess differential information from CEC signals for the detection of colorectal cancer and/or advanced adenoma (AA). Methods: Blood samples and colonoscopy pathology results were obtained from 438 asymptomatic screening subjects enriched for CRC/AA obtained from 15 US medical centers. The cohort included 18 CRCs and 64 AAs. Somatic variants from cfDNA were identified using NGS and qPCR. CECs were captured by the CellMax biomimetic platform (CMx) using high-avidity EpCAM antibody embedded in the CMx biochip and confirmed with immunostaining (DAPI: nucleus, CK20: epithelial cell and CD45: WBC). CMx platform’s AI/ML analyses of CEC images quantify stain intensities and cellular features. CEC derived signal GM1was evaluated for its predictive capability beyond somatic variants from cfDNA. Results: Genetic or epigenetic variants were not detected in 52% (33/64) of AA cases, limiting the sensitivity of these markers for early disease. However, distinct CEC signals have been identified that aid in the detection of subjects with CRC or AA, or conversely subjects with negative colonoscopies or non-advanced adenomas (nAA). Among them, a novel feature (referred to as GM1) derived from CEC signals was able to differentiate with statistical significance AA from negative/non-neoplastic findings or nAAs in study subjects with negative results in corresponding somatic variants from cfDNA (p < 0.0001). While targeted somatic variants from cfDNA performed well on CRC (17/18), they provided no predictive information for detection of AA for the 353 subjects which were negative for variants, GM1 provided 100.0% (33/33) sensitivity at 35.1% (112/319) specificity, showing its ability to rule out AA with high negative predictive value. Conclusions: Somatic variant detection modes of the First Sight multi-modal assay have high sensitivity for CRC and modest sensitivity for AA. We demonstrate that CEC signal GM1 of FirstSight provides significant independent information for the detection of CRC and AA beyond somatic variants from cfDNA. Additional CEC signals may further improve the sensitivity and specificity for detection of early-stage colorectal neoplasia. The GM1 CEC signal marker will need to be validated further in future studies.

Background and Aims: There is a lack of convenient, sensitive, noninvasive strategies for screening and surveillance for colorectal neoplasia. An assay combining the results of circulating epithelial cells (CECs) and somatic mutations of cell-free DNA adjusting for age/sex using a unique algorithm is evaluated in patients requiring colonoscopy. Methods: A prospective single-site 458-subject study (asymptomatic: 43% screening/43% surveillance, enriched with 65 symptomatic subjects undergoing colonoscopy) was conducted. The test analyzed CECs and somatic mutations. The probability of advanced neoplasia (advanced adenoma [AA] and CRCs) was determined by logistic regression methods adjusted for expected CRC incidence rate, prior history of AA, and patient age and sex on a training subset. A linear predictor was developed to generate a score scaled from 0 to 100. The test performance was evaluated on an independent set of subjects using prespecified algorithms and cut point. Results: Based on a predefined clinical threshold and predictive model derived from the training set (n = 232), analysis of an independent asymptomatic validation set (n = 194) yielded 89% (lower exact one-sided 95% confidence interval [CI]: 80%) specificity and 100% (95% CI: 37%)/78% (95% CI: 61%) sensitivity for detection of CRC/AA. In a secondary analysis, excluding surveillance subjects, the 97-subject screening cohort yielded 91% (95% CI: 79%) specificity and CRC/AA sensitivity at 100% (95% CI: 37%)/83% (95% CI: 56%, 87% for advanced neoplasia 95% CI: 64%). Significant associations (P < .0001) were detected between FirstSight scores and adenoma size, number, and ordinally increasing pathology classification. Conclusion: A multimodal blood test that included CECs and somatic mutations with adjustment for age and sex demonstrated high sensitivity for the diagnosis of advanced colorectal neoplasia. The resulting score captures prognostic information for CRC progression of index adenoma size and number and has the potential to enable stratification of patients for screening or postpolypectomy surveillance colonoscopy.

1555 Background: Colonoscopic polypectomy is the primary reason for declining colorectal cancer incidence and mortality. Epidemiological evidence has ordered the timing and risk of pre-cancerous adenomas, localized and invasive cancer along a 7-10 year continuum. The increased size and number of index polyps are correlated with an increased probability of progression to cancer and informs surveillance colonoscopies. Methods: A single-center, IRB-approved, prospective, blinded study was conducted at the VA Palo Alto Health Care System. Results for 354 patients with no prior diagnosis of CRC who were scheduled for colonoscopy are presented. Indications for colonoscopy were 86% asymptomatic and 14% with symptoms or positive-FIT. Patients had blood drawn immediately prior to colonoscopy. The test analyzes three biomarkers: circulating gastrointestinal epithelial cells (CEC), validated somatic mutations, and methylation (SEPTIN9) of cell-free DNA and uses incident risk to calculate a CMx Score, scaled from 0 to 100. Multivariate regression methods were used to assess the degree of association between the pre-defined CMx Scores and polyp sizes and number, adjusting for both DNA mutation and DNA methylation status. Results: There is a significant association between CMx Scores and polyp size (F value = 5.80, p-value = 0.017). DNA mutation (F value = 1.29, p-value = 0.263) and methylation status (F value = 0.34, p-value = 0.560) were non-significant. Similarly, there is a significant association between CMx Scores and number of polyps (F value = 23.71, p-value < 0.0001). Again, DNA mutation (F value = 1.57, p-value = 0.210) and methylation status (F value = 1.34, p-value = 0.248) were non-significant. These results suggest that CMx Scores, which incorporate CEC, are providing predictive information of polyp sizes and number above and beyond DNA mutation and methylation status alone. Conclusions: A novel noninvasive multimodal blood-based assay that analyzes cell-free DNA for somatic mutations and methylation, CEC and integrates SEER incidence risk is significantly associated with polyp size and number. The opportunity to track progression and potentially inform colonoscopy interval is notable. [Table: see text]

We evaluated the analytical and clinical performance of a novel circulating tumor cell (CTC)-based blood test for determination of programmed death ligand 1 (PD-L1) protein expression status in real time in treatment-naïve non-small cell lung cancer (NSCLC) patients. CTCs were detected in 86% of patients with NSCLC (I–IV) at the time of diagnosis, with a 67% PD-L1 positivity rate (≥ 1 PDL + CTC). Among 33 NSCLC patients with PD-L1 results available via both tissue immunohistochemistry (IHC) and CTC assays, 78.9% were positive according to both methods. The CTC test identified an additional ten cases that were positive for PD-L1 expression but that tested negative via IHC analysis. Detection of higher PD-L1 expression on CTCs compared to that in the corresponding tissue was concordant with data obtained using other platforms in previously treated patients. The concordance in PD-L1 expression between tissue and CTCs was approximately 57%, which is higher than that reported by others. In summary, evaluation of PD-L1 protein expression status on CTCs isolated from NSCLC patients is feasible. PD-L1 expression status on CTCs can be determined serially during the disease course, thus overcoming the myriad challenges associated with tissue analysis.

Objective To evaluate the analytical performance of a 98-gene NGS panel designed to detect highly- penetrant, rare pathogenic germline variants, strongly linked to predisposition of cancers in Taiwan and USA. Methods This 98-gene panel was developed following an extensive review of genes with a strong clinical and genetic linkage evidence for cancer predisposition. Probes covering the exon sequences from these 98 genes were validated using 19 samples obtained from the Platinum Genomes Project and the Genome In A Bottle Consortium. Analytical sensitivity and specificity for the detection of clinically important variants within multiple cancers types were demonstrated in 30 reference samples derived from patients with familial cancers. Additionally, two clinical cohorts of 1885 and 374 subjects from Taiwan and USA, respectively, were screened for detection of rare pathogenic germline variants in our CAP accredited laboratory in Taiwan, and CLIA certified laboratory in the USA. Results The analytical sensitivity and specificity of the assay panel were 99.95% and 100%, respectively. Similarly, the reportable variants for all 30 DNA samples containing clinically important SNVs in BRCA1/2, RET, APC, MEN1 and PTEN were called with no false positives. The concordance for the use of either blood (reference lab) or saliva (internal lab) as a sample source was found to be 99.9%. The mean age of the Taiwan cohort was 43, with 58% males and 42% females, while the US cohort had a mean age of 58 with 40% males and 60% females. Germline pathogenic variants were detected in 47/1885 (2.5%) and 25/374 (6.7%) individuals respectively. Outside of BRCA1 and BRCA2 positive cases in Taiwan (8.5% and 17%) and US (4% and 0%), the remaining germline positive cohort had pathogenic variants detected in MUTYH, MLH1, RET, ATM, APC, CHEK2, ERCC2, PALB2, PTCH1, WRN, BARD1, BRIP1, PMS2, PTEN, RAD51D, SDHD, RUNX1, BLM, HOXB13, and MSH6. Stratification of pathogenic variants among high risk and average risk individuals suggests these variants are distributed in both risk groups. Using a multigene approach, we identified 35/47 (87%) and 24/25 (96%) additional cases with rare pathogenic mutations respectively which would not have been identified if we were only looking for BRCA1/2 mutations. Conclusion We have demonstrated in 2 clinical cohorts the analytical and clinical validity of a 98-gene panel for the detection of pathogenic germline variants predisposing to cancer. High sensitivity and specificity of this panel was demonstrated irrespective of the use of blood or saliva as samples. Citation Format: Zulfiqar Gulzar, Julian Lucas, Alex Atkins, stephen Su, Oscar Segurado, Rui Mei. Comparison of rare pathogenic germline variants associated with cancer predisposition syndrome in Taiwan and USA populations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2241.

Introduction: Cryoballoon ablation collateral injury such as atrial-esophageal fistula (AEF) has been reported. Dosing regimens such as the Freeze-thaw-refreeze technique are often used; however, the effect on esophageal rewarming profile is not well understood. The goal of this study is to obtain objective evidence supporting the monitoring of esophageal temperature and the avoidance of the freeze-thaw-freeze technique to reduce injury. Methods: Thirty patients undergoing cryoballoon ablation had their esophageal temperatures measured throughout the procedure using the Circa S-CathTM. Patients underwent ablation with the 28mm Arctic Front Advance® cryoballoon with dosing times of < 180 seconds. No consecutive ablations were performed. Temperature profiles using the readings from the 12 serial sensors were analyzed. Nadir temperature points were used for analysis of esophageal temperature recovery characteristic. Temperature difference intra-pole and esophageal rewarming time was recorded and compared. Results: Successful recording of esophageal temperature was seen in all patients. The average rewarming time on the lowest detected temperature to 35 C recorded. Potential false negative esophageal temperature comparing nadir pole to the neighboring temperature pole was significant (difference in over 10 degrees Celsius) in all recordings. Typical free-thaw-refreeze timing of cryoballoon (1 minute post ablation), would therefore initiate freezing when esophageal temperature are still unrecovered in all of the patients with reduced esophageal temperature. Conclusions: Esophageal temperature rewarming characteristic during cryoballoon is not well understood. Further studies are needed to more accurately assess true esophageal temperature, cooling, as well as rewarming characteristics. Consecutive cryoballoon ablation with free-thaw-refreeze technique, prior to complete esophageal rewarming, will likely result in significant esophageal injury.

Introduction: CardioInsightTM (CIT) high density body surface electrode mapping of atria has been used to identify rotor activities in the atria to guide atrial fibrillation ablation. However, intraprocedural reliability and reproducibility of CIT rotor has not been well-validated. Methods: Eight patients with persistent and long-standing persistent atrial fibrillation were studied prior to ablation with CIT mapping to identify rotors projected onto cardiac CT scan per protocol. Pre-identified CIT rotor activities were used as the baseline for comparison to post ablation CIT rotor map. Ablation of the identified rotors were performed and confirmed by voltage map using the EnSite Velocity System pre and post procedure. Repeated CIT mappings were obtained after each large area modification containing the identified high yield rotor activities area. CIT identified rotors post ablation were compared to pre-ablation. Results: 12 significant rotors were identified by CIT in eight patients. Successful ablation of all of the rotor area with large area ablation was performed with confirmation of no significant residual voltage (<0.1 mV). Intraprocedural post-ablation CIT re-map identified 7/12 rotors in areas of no significant voltage. Conclusions: CIT projection of rotor activity was seen in significant number of confirmed electrically silent areas. The CIT’s ability to correctly project rotor activity on the atrial surfaces was poor. More validation of CIT true projection is needed to guide the ablation of atrial fibrillation.

Compounds 2-5, incorporating various elements of the 3,4'-bis(piperidine) core associated with the sponge-derived alkaloid haliclonacyclamine A (HA, 1), have been prepared through, inter alia, aldol-type reactions of N-substituted piperidin-4-ones and certain derivatives. Screening of these compounds in various assays, including an ecological one, reveals that compound 5 exhibits allelochemical properties similar to those associated with HA itself.

CYT997 was discovered as a potent tubulin polymerization inhibitor possessing potent cytotoxic activity against a range of cancer cells. Details of SAR studies, pharmacokinetic investigations and synthesis of compounds leading to the discovery of CYT997 are reported.

A series of phenylaminopyrimidines has been identified as inhibitors of Janus kinases (JAKs). Development of this initial series led to the potent JAK2/JAK1 inhibitor CYT387 (N-(cyanomethyl)-4-[2-[[4-(4-morpholinyl)phenyl]amino]-4-pyrimidinyl]-benzamide). Details of synthesis and SAR studies of these compounds are reported.

CYT997 is a wholly synthetic compound that possesses highly potent cytotoxic activity in vitro through inhibition of microtubule polymerization. CYT997 blocks the cell cycle at the G(2)-M boundary, and Western blot analysis indicates an increase in phosphorylated Bcl-2, along with increased expression of cyclin B1. Caspase-3 activation is also observed in cells treated with CYT997 along with the generation of poly(ADP-ribose) polymerase. The compound possesses favorable pharmacokinetic properties, is orally bioavailable, and is efficacious per os in a range of in vivo cancer models, including some refractory to paclitaxel treatment. CYT997 exhibits vascular disrupting activity as measured in vitro by effects on the permeability of human umbilical vein endothelial cell monolayers, and in vivo by effects on tumor blood flow. CYT997 possesses a useful combination of pharmacologic and pharmacokinetic properties and has considerable potential as a novel anticancer agent.

A series of enantiomerically pure C8c–C15 monoseco analogues, 23–30, of the alkaloids cryptopleurine (1) and julandine (2) have been prepared using cinnamyl chloride 37 and (S)- or (R)-2-methylpiperidine as key building blocks. Two related compounds, 31 and 32, have also been synthesized. Each of these analogues has been subjected to various biological evaluations and most of them show dramatically reduced cytotoxicity compared with parent system 1. Nevertheless, they are potent anti-angiogenic agents. The formation and single-crystal X-ray analysis of the spirocyclic dienone 54, a by-product arising from attempts to prepare analogue 32, is also described.

A series of 2-(alpha-methylbenzylamino) pyrazines have shown to be potent inhibitors of the FMS tyrosine receptor kinase. Details of SAR studies, modeling and synthesis of compounds within this series are reported.