Demeure, Michael J.

LBA10509 Background: The MCED test (Galleri) detects a shared cancer signal from cell-free DNA in blood and predicts a cancer signal origin (CSO) to guide diagnostic (dx) workup. PF2 (NCT05155605) is a large, prospective, multicenter, interventional study of the MCED test’s performance and safety in a diverse US intended-use population. Methods: PF2 enrolled participants aged ≥50y without clinical suspicion of cancer or cancer diagnosis/treatment within 3y of enrollment. Primary objectives were MCED performance and safety in terms of dx testing triggered by a positive (cancer signal detected) MCED test result. Participants with a positive MCED test underwent targeted dx workup guided by the predicted CSO(s). Participant-reported anxiety was assessed with the State Trait Anxiety Inventory. Results: PF2 enrolled 35,878 participants; 32,007 with a 12m cancer assessment were analyzable for performance. Of 287 (0.9%) with a positive MCED test, 173 were diagnosed with cancer within 12m, for a cancer detection rate of 0.5% (95% CI 0.5-0.6%) and positive predictive value of 60.3% (54.5-65.8%). Specificity was 99.6% (99.6-99.7%). 12m episode sensitivity was 69.8% (62.8-76.0%) in a prespecified subgroup of 12 cancers responsible for ⅔ of US cancer deaths, 66.2% (55.1-75.8%) in a subgroup of 6 aggressive cancers with low 5y survival, and 39.3% (34.9-44.0%) across all cancers. Overall CSO prediction accuracy was 91.3% (86.2-94.7%) across all cancers. The MCED test detected 151 new primary and 22 recurrent cancers; additional cancers detected by screening were those with USPSTF A/B (n=31) and C (n=60) recommended screening. Of 151 MCED-detected new primaries, 80 (53.0%) were clinical stage I-II; 107 (70.9%) were stage I-III. Of 80 MCED-detected stage I-II cancers, 71.2% had no USPSTF A/B screening recommendation. Of 35,335 participants analyzable for safety, 213 (0.6%) had invasive procedure(s) to evaluate a positive MCED test result, of which 90% were nonsurgical and 1.8x more likely for participants with vs without cancer diagnosis. Most (87.6%) had a CSO-guided dx evaluation. There were 5 study-related adverse events during the time of dx workup; none were serious. Anxiety temporarily increased for participants with a positive MCED test and cancer diagnosed, and returned to baseline by 12m. Of participants with a positive MCED test, median time from test result to dx resolution was 48d (95% CI 43-56). Few participants (7/63 [11.1%]) had cancer found by dx PET/CT after a targeted dx workup that did not reveal cancer. Conclusion: The MCED test demonstrated robust performance with a favorable safety profile. When MCED testing was added to USPSTF A/B screening, 6.5x more cancers were detected by screening, most at early stages. The diverse, representative PF2 participant population supports the generalizability of these findings to the US intended-use population. Clinical trial information: NCT05155605 .

632 Background: Paltusotine is an oral, nonpeptide, selective somatostatin receptor 2 agonist. In a phase 2 study, treatment with once-daily paltusotine reduced the frequency and severity of carcinoid syndrome (CS) symptoms and was well tolerated. The effect of paltusotine on biomarkers of serotonin and 5-hydroxyindoleacetic acid (5-HIAA) was further explored. Methods: This exploratory study, without formal power calculations, included an 8-week randomized treatment phase (completed) and a 102-week open-label extension phase (currently ongoing). The purpose was to evaluate safety, pharmacokinetics, and exploratory efficacy endpoints, including changes in biomarkers of paltusotine treatment. Enrolled patients were adults with a stable, documented grade 1 or 2 neuroendocrine tumor (NET) and CS. These patients were actively symptomatic and either untreated with somatostatin receptor ligand (SRL) therapy (average of ≥4 bowel movements [BMs] per day or >2 flushing episodes per day in ≥2 days over a 2-week period) or washed out of SRL therapy (symptoms previously controlled on SRL), with demonstrated symptom worsening after washout. Patients were randomized to once-daily paltusotine 40 mg or 80 mg; one optional uptitration (from 40 mg to 80 mg or 80 mg to 120 mg) was permitted. Blood samples for assessment of biomarkers (serum serotonin and plasma 5-HIAA) were collected longitudinally from screening to end of treatment. Upper limit of normal was prespecified as 541 ng/mL for serotonin and 22 ng/mL for 5-HIAA. This analysis focuses on changes in biomarker from baseline to the end of 8-week randomized treatment phase and after approximately one year (48 weeks). Results: Thirty-six patients (n=9 untreated; n=27 SRL washout) were randomized. Mean age was 60.8 years (range 35-83), and 52.8% were female. Nineteen patients had grade 1 NETs, and 17 had grade 2 NETs. As reported previously, treatment with once-daily, oral paltusotine was well tolerated and reduced the frequency and severity of CS symptoms, justifying further clinical development of the 80 mg dose. Mean serum serotonin decreased from 1553.0 ng/mL at baseline to 643.9 ng/mL at Week 8, and mean plasma 5-HIAA decreased from 245.1 ng/mL to 159.7 ng/mL. There was a trend of untreated patients achieving a greater reduction in comparison to washout patients. At 48-week follow-up, mean serum serotonin was stabilized at 791.50 ng/mL (n=20), and mean plasma 5-HIAA was stabilized at 190.45 ng/mL (n=20). Conclusions: Paltusotine significantly reduced serotonin and 5-HIAA levels, with effects maintained at 48 weeks. Biomarker reductions paralleled reductions in BM and flushing frequency. These findings support further investigation in the ongoing phase 3 study (CAREFNDR, NCT07087054). Clinical trial information: NCT05361668 .

Abstract Background: Multi-cancer early detection (MCED) tests are being established as a novel approach to screen for multiple cancer types with one test. A blood-based MCED test using cell-free DNA targeted methylation patterns to detect a shared cancer signal and predict a cancer signal origin (CSO) has demonstrated feasibility. An initial return of results study (PATHFINDER; NCT04241796) reported performance of a refined version of the MCED test, including a 43.1% positive predictive value (PPV), 98.5% negative predictive value (NPV), 99.5% specificity, and 88.0% CSO accuracy. To build on this work, the PATHFINDER 2 study (NCT05155605) will evaluate safety and performance of the MCED test in larger, more diverse populations. Methods: PATHFINDER 2 is a prospective, multicenter, interventional study. Participants ≥50 years of age will be enrolled, with specific targets to improve diversity (age, sex, race/ethnicity) and few exclusions due to comorbid conditions. Exclusion criteria include current clinical suspicion of cancer or recent cancer/treatment (within 3 years). Participants will undergo blood draw for MCED testing, followed by return of results (cancer signal detection and CSO) to the investigator and diagnostic evaluations if a cancer signal is detected. A confirmatory PET-CT scan will be performed when CSO-directed workups do not result in a cancer diagnosis. Participants will be followed for approximately 3 years. Primary endpoints include 1) MCED test safety in terms of diagnostic testing triggered by a positive result (number/type of procedures and adverse events) and 2) test performance (PPV, NPV, specificity, sensitivity, CSO accuracy, cancer detection rate and number needed to screen). Secondary endpoints include participant reported outcomes (eg, anxiety), utilization of guideline-recommended cancer screening, and cancer detection rate of confirmatory PET-CT, amongst others. The study plans to enroll approximately 35,000 participants across North America. Sites were selected based on geographic location, catchment area demographics, and practice setting (academic vs non-academic). Enrollment targets for age, sex and race/ethnicity (White [non-Hispanic] 72%; Hispanic or Latino 11%; African American or Black 11%; Asian, Native Hawaiian or Other Pacific Islander 6%; American Indian/Alaska Native 1%) were derived from US Census data. Strategies to promote diverse recruitment include translation of participant-facing documents across multiple languages, participant and healthcare provider educational material, and site-led community outreach campaigns. MCED testing is an emerging, potentially paradigm-changing strategy in cancer screening, and PATHFINDER 2 is designed to characterize the safety, performance, and clinical implementation of the MCED test as a screening tool in a broad and representative population. Citation Format: Karthik V. Giridhar, Michael J. Demeure, Raymond H. Kim, Justin A. Chen, Shirish Gadgeel, Dax Kurbegov, Margarita Lopatin, Roland Matthews, Marc Matrana, Charles McDonnell, Donald Richards, Benjamin Rybicki, Gretchen Stipec, Nima Nabavizadeh. PATHFINDER 2: A prospective study to evaluate safety and performance of a multi-cancer early detection test in a population setting [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4784.

10572 Background: Adrenocortical carcinoma (ACC) is a rare and lethal cancer with an average incidence of 1 in 1.4 million. Response to current standard therapy including mitotane is approximately 22%. Herein we use gene expression profiling to identify novel targets for therapeutic intervention. Methods: The transcriptomes of 29 ACC tumors and 4 normal adrenal glands were profiled on Affymetrix Human Genome and Agilent 22K element expression arrays in order to identify genes that could represent potential therapeutic targets. Agents known to inhibit the selected targets were tested in comparison with mitotane in two ACC cell lines (H295R and SW-13) in vitro and are currently being tested in a Scid mouse xenograft system. Results: Expression of numerous kinesin family members is dysregulated within the ACC tumor population. Of interest in the ACC cells EG5 (KIF11, KSP), a kinesin important for mitotic spindle formation, is up-regulated 5.81+ 4.42 (μ+SD) and 6.48 + 0.99 fold on the Agilent and Affymetrix platforms respectively. In addition, SPARC, an albumin binding matrix associated protein is up-regulated in ACC tumors by 3.69 + 2.37 (μ+SD) and 1.56 + 0.44 on the two platforms. The anti-microtubular drugs paclitaxel and albumin bound paclitaxel (abraxane) exhibited in vitro inhibition of H295R and SW-13 cells at IC50 concentrations of 0.33 μM and 0.0078 μM for paclitaxel and 0.35 μM and 0.0087 μM for Abraxane compared to mitotane concentrations of 15.9 μM and 46.4 μM. Treatment effects of monastrol, paclitaxel, and Abraxane are currently being tested in xenograft murine models. Testing of the EG5 inhibitor S-trityl-L- cysteine is ongoing in the in vitro system. Conclusions: KIF11 inhibitors have been proposed in the treatment of cancer. These compounds may offer better anti-mitotic activity than other tubulin interacting agents with less neurotoxic side effects. Based on biological insight garnered through expression profiling of ACC tumors, the current ongoing research is investigating the use of abraxane and EG5 inhibitors in the in vitro and in vivo treatment of ACC. No significant financial relationships to disclose.

Abstract Purpose: Pancreatic adenocarcinoma is among the most lethal forms of all malignancies. While significant research has implicated multiple genes in disease pathogenesis, identification of therapeutic leads has been difficult. The majority of currently available therapies provide only marginal benefit. To address this issue, our goal was to assess global somatic events across multiple pancreatic tumors by using next-generation sequencing technologies (NGS). Experimental Design: We performed whole genome sequencing (WGS) on paired tumor and normal samples from 3 pancreatic adenocarcinoma patients. Additionally, we performed whole transcriptome sequencing (WTS) on 2 of these patients’ tumors for which tumor RNA was available. Results: We generated on average 132 billion mappable bases across all patients using WGS, and identified 140 somatic coding events including point mutations, insertion/deletions, and chromosomal copy number variants. Data from WGS and WTS were integrated and analyzed to identify the most heavily affected pancreatic cancer pathways across all patients. The KRAS signaling pathway was identified as the most significant map. Unbiased global pathway analysis was also performed to identify processes that may be impacted. Consistent with the previous analysis, the most significant pathway from this analysis is also KRAS signaling. This integrated analysis specifically identifies heavily affected pathways in pancreatic cancer and pinpoints genes and processes that may be considered as targets for more effective therapies. Conclusions: While sequencing of additional patients is necessary to strengthen selection of key pathways, we demonstrate the utility of using NGS to understand the processes driving pancreatic adenocarcinoma so that standardized treatments for patients may be improved. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5104. doi:1538-7445.AM2012-5104

Abstract Adrenocortical carcinoma (ACC) is an aggressive cancer with a 5-year survival rate of 20-30%. Mitotane is the only approved drug for the treatment of patients with ACC. It often carries significant toxicities which result in the discontinuation of treatment. There are no approved second line therapies. The increased incidence of ACC in the cancer predisposition syndrome, Li-Fraumeni, suggests the involvement of the p53 pathway in ACC pathogenesis. Our analysis of the gene expression profiles of 19 ACC samples identified dysregulation of the G2/M transition and the activity of the p53 modulator, MDM2 as important in ACC pathogenesis. Polo-like kinase-1 (PLK1) is involved in the G2/M transition and acts to promote MDM2 activity through its phosphorylation. We observed that PLK1 inhibition by siRNA results in up to a 70% reduction in viability in the ACC cell lines SW-13 and H295R. Therefore, we studied PLK1 inhibition as a potential therapeutic strategy. We used the small molecule inhibitor, BI-2536, to inhibit PLK1 function in SW-13 and H295R. Drug-dose response curves demonstrated that both cell lines are sensitive to pharmacological inhibition of PLK1 (IC50 doses of 0.0094815 μM and 0.062805 μM for SW-13 and H295R, respectively.) Murine xenograft studies demonstrated that BI-2536 resulted in a statistically significant reduction in tumor growth in SW-13 but not H295R. Examination of p53 protein levels in the presence of the drug showed a dose-dependent reduction in p53 levels in SW-13, which carries a homozygous p53 mutation. The same was not true in H295R, which is p53 wild-type. To test the hypothesis that BI-2536 was decreasing mutant p53 levels by promoting its proteasomal degradation, both cell lines were treated with previously determined inhibitory concentrations of BI-2536, either alone or in combination with the proteasome inhibitor, MG132. Western blot analysis showed recovery of p53 protein when cells were concomitantly treated with MG132, supporting a role for BI-2536 as a regulator of proteasomal degradation. Both ACC cell lines are relatively insensitive to MDM2 inhibition by nutlin-3 (NCI60 GI50 values range from ∼4 uM to ∼2 uM versus ACC cell lines @13-15uM), possibly because PLK1 stimulates MDM2 and renders nutlin-3 ineffective. We therefore assessed the ability of BI-2536 to sensitize ACC cell lines to the effects of the MDM2 inhibitor. BI-2636 did show synergy with nutlin-3, shifting the IC50 in SW-13 from 19.78 μM to 6.45 μM and from 12.75 μM to 2.84 μM in H295R. These results demonstrate that inhibition of PLK1 alone or in combination with an MDM2 inhibitor warrants further investigation as a treatment for patients with ACC. Cells with mutant p53 are more sensitive to the growth inhibitory effects of BI-2536. In the context of wild-type p53, the combined inhibition of both PLK1 and MDM2 results in loss of viability. Further clinical development of PLK1 as a target should take p53 mutation status into account. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 978. doi:1538-7445.AM2012-978

Abstract Quiescin-sulfhydryl oxidase (QSOX1) oxidizes sulfhydryl groups to form disulfide bonds in proteins. We previously mapped a peptide in plasma from pancreatic ductal adenocarcinoma patients back to an overexpressed QSOX1 parent protein in tumor cells. It is not known why, or in what capacity, pancreatic tumors overexpress QSOX1. To begin to address this question, we first showed through immunohistochemistry that QSOX1 is overexpressed in patients diagnosed with pancreatic cancer, while it is not expressed in adjacent normal tissue or infiltrating lymphocytes. To determine the potential advantages QSOX1 might provide to tumor cells we knocked down QSOX1 using shRNA that suppressed both short and long isoforms of the protein. Loss of QSOX1 expression suppressed cell growth over time, while changes in cell cycle and apoptotic markers were minimal. However, QSOX1 shRNA dramatically inhibited the abilities of BxPC3 and Panc-1 pancreatic tumor cells to invade through Matrigel in a modified Boyden chamber assay. Mechanistically, gelatin zymography indicated that QSOX1 may play an important role in intracellular processing and extracellular activation of MMP-2 and MMP-9. Taken together, our results suggest that pancreatic tumors that express QSOX1 demonstrate an invasive phenotype through MMP activation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr B60.

Abstract Quiescin sulfhydryl oxidase 1 (QSOX1) oxidizes sulfhydryl groups to form disulfide bonds in proteins. We previously mapped a peptide in plasma from pancreatic ductal adenocarcinoma (PDA) patients back to an overexpressed QSOX1 parent protein. In addition to overexpression in pancreatic cancer cell lines, 29 of 37 patients diagnosed with PDA expressed QSOX1 protein in tumor cells, but QSOX1 was not detected in normal adjacent tissues or in a transformed, but nontumorigenic cell line. To begin to evaluate the advantage QSOX1 might provide to tumors, we suppressed QSOX1 protein expression using short hairpin (sh) RNA in two pancreatic cancer cell lines. Growth, cell cycle, apoptosis, invasion, and matrix metalloproteinase (MMP) activity were evaluated. QSOX1 shRNA suppressed both short and long isoforms of the protein, showing a significant effect on cell growth, cell cycle, and apoptosis. However, QSOX1 shRNA dramatically inhibited the abilities of BxPC-3 and Panc-1 pancreatic tumor cells to invade through Matrigel in a modified Boyden chamber assay. Mechanistically, gelatin zymography indicated that QSOX1 plays an important role in activation of MMP-2 and MMP-9. Taken together, our results suggest that the mechanism of QSOX1-mediated tumor cell invasion is by activation of MMP-2 and MMP-9. Mol Cancer Res; 9(12); 1621–31. ©2011 AACR.