Lopatin, Margarita

Abstract A blood-based multi-cancer early detection (MCED) test has demonstrated feasibility as a screening tool in large-scale clinical trials. The PATHFINDER 2 (PF2) study (NCT05155605) evaluates safety and performance of the MCED test in a diverse intended-use population. To gauge generalizability of study results, we assessed participant (ppt) baseline characteristics vs general US population data from the National Health and Nutrition Examination Survey (NHANES). PF2, a prospective, multicenter, interventional study, enrolled ppts aged ≥50 y from diverse clinical settings in North America. Enrollment targets for sex and race/ethnicity were established from the 2019 American Community Survey (US Census Bureau). Recruitment strategies were implemented to maximize enrollment for groups historically underrepresented in clinical studies. Exclusion criteria included clinical suspicion of cancer or cancer diagnosis/treatment within 3 y. Data on baseline characteristics and key cancer risk factors were collected at enrollment. We compared the PF2 study population to a nationally representative sample of US adults aged ≥50 y from 2017-2020 NHANES data. NHANES data were weighted using complex, multistage probability sampling to generate a nationally representative sample. There were 35,878 ppts enrolled in PF2; 35,307 clinically eligible and evaluable ppts were included in this analysis. Mean age was 64 y for both PF2 and NHANES; 56.2% were females in PF2 vs 53.6% (95% CI 52.0-55.3%) in NHANES. Race/ethnicity distribution for PF2 vs NHANES was 7.4 vs 11.0% (8.9-13.1%) Hispanic, 74.6 vs 69.7% (65.0-74.5%) non-Hispanic (NH) White, 8.6 vs 10.3% (7.6-13.1%) NH Black, and 5.8 vs 5.1% (3.5-6.8%) NH Asian. In terms of lifestyle characteristics for PF2 vs NHANES, 58.9 vs 29.2% (25.8-32.7%) had at least a bachelor’s degree, 74.8 vs 63.8% (60.6-67.0%) were married/living with a partner, 69.3 vs 53.8% (50.9-56.7%) had never smoked, 66.5 vs 70.4% (68.0-72.8%) were overweight/obese, and 24.2 vs 28.4% (26.4-30.3%) reported never using alcohol. PF2 enrolled a diverse ppt population that is reasonably reflective of the demographics of the US population aged ≥50 y. As is typical for clinical trials, a higher percentage of PF2 vs NHANES ppts reported lifestyle characteristics associated with better health. As the study population largely reflects the MCED test intended-use population, safety and performance results from PF2 are expected to reflect real-world clinical experience. Citation Format: Shirish Gadgeel, Nima Nabavizadeh, Dax Kurbegov, Charles McDonnell, III, James W. Lillard, Jr., Marc Matrana, Alan Roth, Andrea Johnston, Sami Tahhan, Rami Owera, Matthew Margolis, Anuraag Kansal, Margarita Lopatin, Margaret McCusker, Karthik V. Giridhar. Baseline participant characteristics from PATHFINDER 2, a prospective interventional study of a multi-cancer early detection test in a population setting [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr C145.

Abstract Blood-based multicancer early detection (MCED) tests represent a new approach for cancer detection. To gain insights into the utility of various approaches of evaluating a cancer signal detected (CSD) test result, we evaluated diagnostic journeys of a subset of 6,662 participants in PATHFINDER who had a CSD on both an initial and refined version of an MCED test that also provided a prediction of cancer signal origin (CSO). We sought to determine whether CSO prediction–guided diagnostic evaluations led to diagnostic resolution; whether participants with known risk factors for cancer beyond age alone and a negative initial diagnostic evaluation had a cancer diagnosis during study follow-up; the utility of whole-body imaging in reaching diagnostic resolution; and differences in the diagnostic journeys needed to reach diagnostic resolution for both true- and false-positive results. Of the 39 participants in this analysis, 82% (32/39) achieved diagnostic resolution after the initial evaluation, including 78% (25/32) who reached resolution specifically with a CSO prediction–directed workup. Eighteen percent (7/39) required additional evaluation for persistent clinical suspicion of cancer, all of whom achieved resolution (3 with and 4 without cancer). Whole-body imaging contributed to diagnostic resolution in only 49% of CSD cases. Approximately 90% of true- and false-positive cases had imaging tests; more true positives versus false positives (81.0% vs. 38.9%) had nonsurgical and/or surgical procedures. In conclusion, CSO prediction–directed evaluations enabled diagnostic resolution for most participants, although some with negative initial evaluations but persistent suspicion of cancer required additional testing. Prevention Relevance: MCED testing has the potential to increase detection of cancer at earlier stages. As MCED testing is a new technology, there are few data on the diagnostic journeys patients undergo following testing. We observed that for most patients, CSO prediction–directed workups were efficient, leading to diagnostic resolution after initial evaluation.

10608 Background: Cancer is one of the most feared diseases. Multi-cancer early detection (MCED) tests have the potential to expand the number of cancers that are detected at earlier stages, which could result in better clinical outcomes. However, behavioral impacts based on MCED test results could affect the utility and value of these tests. Methods: Two independent data sources evaluated the impact of MCED test results on behavioral intentions and perceptions: a survey of the general population and PRO in an MCED clinical trial. A web-based, 30-minute survey of the US general population was used to ascertain attitudes toward a hypothetical MCED test. Eligible respondents were adults aged 40-80 years without a cancer diagnosis in the previous 5 years. The survey assessed the perceived value of negative results (ie, no cancer signal detected [NCSD]) and the projected impact on post-test behaviors. The prospective PATHFINDER study (NCT04241796) of adults aged ≥50 years who underwent MCED cancer screening included PRO assessments. Post-test assessments included: "I am feeling relieved about my test result" from the adapted MICRA and “How likely are you to follow your healthcare provider’s cancer screening recommendations.” The consistency of sentiment after an NCSD MCED result from the online survey and clinical study was assessed. Results: Of the 1073 online survey respondents, 53% were female, 77% White, 14% Black/African American, and 13% Hispanic. Mean age was 58 years. The most common anticipated emotional impacts were relief (84%), happiness (72%), and confidence (69%). Respondents (66-70%) reported they would expect less worry, fear, stress, and anxiety after an NCSD MCED result. The majority (73%) reported they would maintain or improve health behaviors after an NCSD result. NCSD results were projected to lead to an increase in health-related behaviors, including adherence to recommended cancer screening (98%; 68% increase, 30% maintain current level) and regular doctor visits (46%). Of the 6529 PATHFINDER study participants who received NCSD results, 64% were female, 92% White. Mean age was 63 years. 80% of participants (n = 4685/5865) with NCSD felt relief "sometimes" or "often" after their MCED test result. Over 95% of participants (n = 5637/5863) with NCSD indicated they were "likely" or "very likely" to adhere to cancer screening recommendations in the future. Conclusions: Results from a general population survey and a prospective clinical study indicate that an NCSD result may be associated with positive cancer screening intentions and other preventive healthcare behaviors. An NCSD result may also positively impact psychological and emotional health. While these findings suggest that an NCSD result may provide additional value beyond traditional clinical benefits associated with cancer screening, future research is needed to delineate the behavioral impact following MCED screening. Clinical trial information: NCT04241796 .

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.

10520 Background: PATHFINDER (NCT04241796) was a prospective, interventional return of results study that enrolled 6,662 participants (pts) from 7 US institutions to assess clinical implementation of a blood-based multi-cancer early detection (MCED) test. Test results for those with a cancer signal detected also included a cancer signal origin prediction designed to help guide diagnostic evaluations. We analyzed whether the diagnostic evaluations in PATHFINDER were appropriately directed by cancer signal origin predictions, assessed the residual risk of cancer after negative initial evaluation, and examined the role of whole-body imaging (WBI, defined as PET/CT or CT chest/abdomen/pelvis) in diagnostic evaluation. Methods: Analysis included pts with a cancer signal detected result from the two different versions of an MCED test evaluated in PATHFINDER. Prespecified criteria blinded to study results were used to define expected diagnostic evaluations by cancer signal origin prediction. These criteria were then used to judge concordance between cancer signal origin predictions and the diagnostic evaluation actually performed. Definitive cancer or no cancer diagnosis (cancer status at end of study [EOS]) was assessed at 12 months after enrollment (EOS). Results: 39 pts had cancer signal detected results by both test versions. Diagnostic evaluations were consistent with cancer signal origin in 30/39 (77%) cases. Diagnostic resolution was achieved in 32/39 (82%) pts after initial evaluation, while 7/39 (18%) required additional workup. 25 of the 32 (78%) pts who achieved diagnostic resolution after initial evaluation had a cancer signal origin-guided workup. Additional evaluation of the 7 pts not achieving initial diagnostic resolution was based on persistent clinical suspicion of cancer due to prior cancer history (n = 1) or abnormal/equivocal findings on initial evaluation (n = 6). Additional workup led to diagnostic resolution in all 7 cases (3 with cancer and 4 with no cancer confirmed at EOS). WBI was ordered in 27 cases, of whom 9 had a prior cancer history, 10 had non-localizing cancer signal origin (hematologic or indeterminate), and 1 had both. WBI was equivocal or had no impact on diagnostic resolution in 8/27 (30%) cases. Conclusions: Most cases resulted in diagnostic resolution after cancer signal origin-directed diagnostic workup. In pts with a cancer history and negative initial evaluations, and those with equivocal initial evaluations, there was still a risk of cancer, suggesting the need for additional evaluation. WBI was used mostly in those with a cancer history or non-localizing cancer signal origins, and had no impact on diagnosis in almost one-third of pts. Clinical trial information: NCT04241796 .

To examine the extent of the evaluation required to achieve diagnostic resolution and the test performance characteristics of a targeted methylation cell-free DNA (cfDNA)-based multi-cancer early detection (MCED) test, ~6200 participants ≥50 years with (cohort A) or without (cohort B) ≥1 of 3 additional specific cancer risk factors will be enrolled in PATHFINDER (NCT04241796), a prospective, longitudinal, interventional, multi-center study. Plasma cfDNA from blood samples will be analyzed to detect abnormally methylated DNA associated with cancer (i.e., cancer “signal”) and a cancer signal origin (i.e., tissue of origin). Participants with a “signal detected” will undergo further diagnostic evaluation per guiding physician discretion; those with a “signal not detected” will be advised to continue guideline-recommended screening. The primary objective will be to assess the number and types of subsequent diagnostic tests needed for diagnostic resolution. Based on microsimulations (using estimates of cancer incidence and dwell times) of the typical risk profiles of anticipated participants, the median (95% CI) number of participants with a “signal detected” result is expected to be 106 (87–128). Subsequent diagnostic evaluation is expected to detect 52 (39–67) cancers. The positive predictive value of the MCED test is expected to be 49% (39–58%). PATHFINDER will evaluate the integration of a cfDNA-based MCED test into existing clinical cancer diagnostic pathways. The study design of PATHFINDER is described here.

3070 Background: A multi-cancer early detection (MCED) test that uses targeted methylation-based cfDNA technology to detect cancer and predict cancer signal origin (CSO) has potential to efficiently identify malignancies for which effective screening modalities do not exist. A previous version of a blood-based MCED test demonstrated favorable classification and test characteristics. Samples from the ongoing PATHFINDER study were reanalyzed in a prespecified interim analysis to evaluate performance of a more recent version of the test with an updated classifier (eg, updated CSO localization, hematological signal threshold) that is planned for clinical implementation as a general multi-cancer screening tool. Methods: PATHFINDER (NCT04241796) is an interventional, prospective study in which results (cancer signal detected/not detected and predicted CSO) using a previous version of the MCED test are returned to investigators, and those with a signal detected undergo further diagnostic testing. In this prespecified interim analysis, samples from those enrolled as of October 6, 2020 were reanalyzed with the more recent version of the MCED test (these results were not returned to investigators). The positive predictive value (PPV) for cancer detection, overall CSO accuracy, and concordance between the two test versions were assessed. Results: A total of 4011/4047 (99%) participants (pts) were analyzable (mean [SD] age 63.9 [8.7] years, 62% female, 92% white, 24% with prior cancer history, 39% ever smoker [4% current], 6% with genetic cancer predisposition). Cancer signal was detected in 0.95% (38/4011). A total of 27/38 also had signal detected by the previous version of the MCED test, including 19 who reached diagnostic resolution (13 with cancer diagnosis and 6 without); 11/38 were discordant positives. Nine different cancer types were detected in the 13 pts (2 stage I, 3 stage II, 2 stage III, and 3 stage IV); 1 had no AJCC stage expected, 1 metastatic recurrence and 1 stage evaluation underway. A conservative minimal PPV assuming all discordant positives are false positives, was 43.3% (13/30, 95% CI 27.4-60.8%) based on 19 pts with diagnostic resolution and 11 discordant positives. High negative percent agreement (PA) 99.7% (99.5-99.8%) between the two test versions was observed. Positive PA of 43.5% (95% CI, 31.9-55.9%) was consistent with the more stringent threshold for hematologic signal in the recent MCED version, as most discrepant cases had hematologic CSO with the previous MCED test. Among 13 detected cancers, accuracy of the top CSO prediction was 92.3% (12/13, 95% CI 66.7-99.6%). Conclusions: In this prespecified interim analysis, the more recent version of the MCED test detected cancers with high PPV and high accuracy of CSO prediction, supporting readiness for use in clinical practice. Full enrollment cohort data will be available at the meeting. Clinical trial information: NCT04241796.

3010 Background: PATHFINDER (NCT04241796) is an interventional, prospective study evaluating implementation of a blood-based multi-cancer early detection (MCED) test that uses targeted methylation-based cfDNA analysis to detect multiple cancer types and simultaneously predict cancer signal origin (CSO). We present a prespecified interim analysis of PATHFINDER evaluating an MCED test in a clinical setting. Methods: Participants (pts; ≥50y) were enrolled into 2 risk cohorts: non-elevated and elevated (smoking history, prior cancer [ > 3y post treatment], or genetic predisposition). MCED test results (cancer signal detected/not detected) were returned to investigators; pts with a signal detected also received a CSO prediction and underwent further diagnostic testing by their medical team. The primary objective was to assess the extent of diagnostic testing needed to achieve diagnostic resolution (eg, time to resolution, number/type of tests). Secondary endpoints included positive predictive value (PPV) and a measure of test satisfaction (following diagnostic resolution [signal detected] and post test [signal not detected]). Results: PATHFINDER consented 6796 pts before closing accrual on 12/4/20; as of October 6, 2020, 4086 consented, 4047 enrolled, and 4033 analyzable pts were included in the interim analysis (62.4% female, 92.1% white). Two study-related adverse events (anxiety of mild severity) were reported. Cancer signal was detected in 1.5% (62/4033) of pts; 40/62 reached diagnostic resolution to date. Kaplan-Meier estimate of median time to resolution was 78 (95% CI, 54-151) days. Among 40 pts that reached diagnostic resolution, ≥1 imaging test was performed in 93% (37/40); ≥1 invasive procedure was performed in 72% (13/18) versus 18% (4/22) of pts with diagnostic resolution of cancer versus no cancer, respectively. Based on results to date, PPV was 45% (95% CI, 30.7-60.2%; 18/40). Of 18 cancer diagnoses, 11 were solid tumors (3 stage IV, 6 stages I-III, 1 metastatic recurrence, 1 missing stage), and 7 were hematologic malignancies (1 stage IV, 4 stages I-III, 2 without AJCC stage). Accuracy of the top CSO prediction in true positives was 82.4% (95% CI, 59.0-93.8%; 14/17). Most pts were satisfied with the test (43.7% extremely satisfied, 30.7% very satisfied, 14.6% satisfied). Signal detection rate and test satisfaction were similar in the 2 risk cohorts; PPV tended to be higher in the elevated risk cohort, as expected. Conclusions: An interim analysis of this return of results study demonstrated promising MCED test results. Of 40 pts achieving diagnostic resolution, nearly half had a diagnostic workup confirming cancer; CSO was predicted with high accuracy for detected cancers. Taken together with the rarity of adverse events and high test satisfaction, these results support the feasibility of clinical implementation. Full enrollment cohort data will be available at the meeting. Clinical trial information: NCT04241796.

Abstract Background: Early detection decreases patient mortality for many cancers, but prevailing paradigms focus on distinct screening modalities for each cancer type. A minimally invasive test that detects multiple tumor types could substantially reduce cancer mortality and improve screening efficiency. In preliminary studies, we showed that a targeted methylation cell-free DNA (cfDNA) test can detect cancer and determine the tissue of origin (TOO) of abnormally methylated cfDNA with high sensitivity and specificity; however, blood was collected at the time of diagnosis and results were not disclosed to inform care. The current study includes disclosure of results to the study investigator to understand the care pathways prompted by a “signal detected” test result, and the benefits, harms, and burdens associated with a multi-cancer detection test. Methods: PATHFINDER (NCT04241796) is a prospective, longitudinal, multi-center clinical study. Approximately 6,200 participants with varying levels of cancer risk will be enrolled at 5-10 clinical sites in the United States. Participants must be ≥50 years of age. If participants have at least 1 of the following–a smoking history of ≥100 cigarettes, a genetic cancer predisposition, or a history of invasive or hematologic malignancy with definitive treatment completed >3 years prior to enrollment–they are eligible for the Elevated Risk Cohort (n = 4340); otherwise, they are eligible for the Non-Elevated Risk Cohort (n = 1860). Individuals being evaluated for cancer or who have a history of invasive or hematologic malignancy within 3 years of enrollment will be excluded. Blood drawn at study sites will be analyzed at GRAIL, Inc. (Menlo Park, CA). Participants and study investigators will be informed of the test results. Participants with “signal not detected” results will be advised to continue routine clinical care, including age- and risk-based cancer screening. Those with “signal detected” test results will be informed of the predicted origin and undergo diagnostic evaluation. The primary study objective is to determine the extent of diagnostic testing required to achieve diagnostic resolution following a “signal detected” test result, defined as the date when the study investigator determines to end diagnostic evaluation triggered by a “signal detected” test result. Health resource utilization, the number and types of tests and time required to reach this point, is the primary endpoint. Secondary objectives include evaluation of test performance (specificity, positive predictive value, and TOO accuracy), and assessment of participants' perceptions about the test and changes in anxiety and health-related quality of life. Exploratory aims include assessment of the number and types of invasive cancer diagnoses among participants with “signal not detected” test results and changes in attitude toward adherence to guideline-recommended screening. Citation Format: Lincoln Nadauld, Charles H. McDonnell III, Minetta C. Liu, Eric Klein, Tomasz M. Beer, Deborah Schrag, Andrew G. Hudnut, Richard Whittington, Bruce Taylor, Joanna Tierney, Catherine Marinac, Jafi Lipson, Margarita Lopatin, Karen C. Chung, Eric Fung, Anne-Renee Hartman, Geoffrey R. Oxnard. The PATHFINDER Study: Assessment of the implementation of an investigational multi-cancer early detection test into clinical practice [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT291.