Monitoring response to neoadjuvant chemotherapy in triple negative breast cancer using circulating tumor DNA.

BACKGROUND: Triple negative breast cancer (TNBC) is an aggressive subtype with poor prognosis. We aimed to determine whether circulating tumor DNA (ctDNA) and circulating tumor cell (CTC) could predict response and long-term outcomes to neoadjuvant chemotherapy (NAC). METHODS: Patients with TNBC were enrolled between 2017-2021 at The University of Texas MD Anderson Cancer Center (Houston, TX). Serial plasma samples were collected at four timepoints: pre-NAC (baseline), 12-weeks after NAC (mid-NAC), after NAC/prior to surgery (post-NAC), and one-year after surgery. ctDNA was quantified using a tumor-informed ctDNA assay (SignateraTM, Natera, Inc.) and CTC enumeration using CellSearch. Wilcoxon and Fisher's exact tests were used for comparisons between groups and Kaplan-Meier analysis used for survival outcomes. RESULTS: In total, 37 patients were enrolled. The mean age was 50 and majority of patients had invasive ductal carcinoma (34, 91.9%) with clinical T2, (25, 67.6%) node-negative disease (21, 56.8%). Baseline ctDNA was detected in 90% (27/30) of patients, of whom 70.4% (19/27) achieved ctDNA clearance by mid-NAC. ctDNA clearance at mid-NAC was significantly associated with pathologic complete response (p = 0.02), whereas CTC clearance was not (p = 0.52). There were no differences in overall survival (OS) and recurrence-free survival (RFS) with positive baseline ctDNA and CTC. However, positive ctDNA at mid-NAC was significantly associated with worse OS and RFS (p = 0.0002 and p = 0.0034, respectively). CONCLUSIONS: Early clearance of ctDNA served as a predictive and prognostic marker in TNBC. Personalized ctDNA monitoring during NAC may help predict response and guide treatment.

Predicting recurrent glioblastoma clinical outcome to immune checkpoint inhibition and low-dose bevacizumab with tumor in situ fluid circulating tumor DNA analysis.

OBJECTIVE: Most recurrent glioblastoma (rGBM) patients do not benefit from immune checkpoint inhibition, emphasizing the necessity for response biomarkers. This study evaluates whether tumor in situ fluid (TISF) circulating tumor DNA (ctDNA) could serve as a biomarker for response to low-dose bevacizumab (Bev) plus anti-PD-1 therapy in rGBM patients, aiming to enhance systemic responses to immunotherapy. METHODS: In this phase II trial, 32 GBM patients with first recurrence after standard therapy were enrolled and then received tislelizumab plus low-dose Bev each cycle. TISF samples were analyzed for ctDNA using a 551-gene panel before each treatment. RESULTS: The median progression-free survival (mPFS) and overall survival (mOS) were 8.2 months (95% CI, 5.2-11.1) and 14.3 months (95% CI, 6.5-22.1), respectively. The 12-month OS was 43.8%, and the objective response rate was 56.3%. Patients with more than 20% reduction in the mutant allele fraction and tumor mutational burden after treatment were significantly associated with better prognosis compared to baseline TISF-ctDNA. Among detectable gene mutations, patients with MUC16 mutation, EGFR mutation & amplification, SRSF2 amplification, and H3F3B amplification were significantly associated with worse prognosis. CONCLUSIONS: Low-dose Bev plus anti-PD-1 therapy significantly improves OS in rGBM patients, offering guiding significance for future individualized treatment strategies. TISF-ctDNA can monitor rGBM patients' response to combination therapy and guide treatment. CLINICAL TRIAL REGISTRATION: This trial is registered with ClinicalTrials.gov, NCT05540275.

Clinical outcomes and ctDNA correlates for CAPOX BETR: a phase II trial of capecitabine, oxaliplatin, bevacizumab, trastuzumab in previously untreated advanced HER2+ gastroesophageal adenocarcinoma.

Preclinical studies suggest that simultaneous HER2/VEGF blockade may have cooperative effects in gastroesophageal adenocarcinomas. In a single-arm investigator initiated clinical trial for patients with untreated advanced HER2+ gastroesophageal adenocarcinoma, bevacizumab was added to standard of care capecitabine, oxaliplatin, and trastuzumab in 36 patients (NCT01191697). Primary endpoint was objective response rate and secondary endpoints included safety, duration of response, progression free survival, and overall survival. The study met its primary endpoint with an objective response rate of 81% (95% CI 65-92%). Median progression free and overall survival were 14.0 (95% CI, 11.3-36.4) and 23.2 months (95% CI, 16.6-36.4), respectively. The median duration of response was 14.9 months. The regimen was well tolerated without unexpected or severe toxicities. In post-hoc ctDNA analysis, baseline ctDNA features were prognostic: Higher tumor fraction and alternative MAPK drivers portended worse outcomes. ctDNA at resistance identified oncogenic mutations and these were detectable 2-8 cycles prior to radiographic progression. Capecitabine, oxaliplatin, trastuzumab and bevacizumab shows robust clinical activity in HER2+ gastroesophageal adenocarcinoma. Combination of VEGF inhibitors with chemoimmunotherapy and anti-PD1 regimens is warranted.

Circulating tumour DNA dynamics predict recurrence in stage III melanoma patients receiving neoadjuvant immunotherapy.

BACKGROUND: Neoadjuvant therapy improves recurrence-free survival (RFS) in resectable stage III cutaneous melanoma. However, accurately predicting individual recurrence risk remains a significant challenge. We investigated circulating tumour DNA (ctDNA) as a biomarker for recurrence in measurable stage IIIB/C melanoma patients undergoing neoadjuvant immunotherapy. METHODS: Plasma samples were collected pre-neoadjuvant treatment, pre-surgery and/or six weeks post-surgery from 40 patients enrolled in the OpACIN-neo and PRADO clinical trials. Patients received two cycles of ipilimumab (anti-CTLA-4) and nivolumab (anti-PD-1) before surgery. Cell free DNA (cfDNA) underwent unbiased pre-amplification followed by tumour-informed mutation detection using droplet digital polymerase chain reaction (ddPCR) with the Bio-Rad QX600 PCR system. RESULTS: Pre-treatment ctDNA was detectable in 19/40 (48%) patients. Among these, 17/19 (89%) zero-converted within six weeks of surgery and none recurred. Positive ctDNA post-surgery (N = 4), irrespective of pre-treatment ctDNA status, was 100% predictive of recurrence (sensitivity 44%, specificity 100%). Furthermore, ctDNA cleared prior to surgery in 7/9 (78%) patients who did not recur, warranting further investigation into ctDNA-guided surgical management. CONCLUSION: Post-surgery ctDNA positivity and zero-conversion are highly predictive of recurrence, offering a window for personalised modification of adjuvant therapy.

Construction of scalable multi-channel DNA nanoplatform for the combined detection of ctDNA biomarkers of ovarian cancer.

Single-level biomarker detection has the limitation of insufficient accuracy in cancer diagnosis. Therefore, the strategy of developing highly sensitive, multi-channel biosensors for high-throughput ctDNA determination is critical to improve the accuracy of early diagnosis of clinical tumors. Herein, in order to achieve efficient detection of up to ten targets for early diagnosis of ovarian cancer, a DNA-nanoswitch-based multi-channel (DNA-NSMC) biosensor was built based on the multi-module catalytic hairpin assembly-mediated signal amplification (CHA) and toehold-mediated DNA strand displacement (TDSD) reaction. Only two different fluorescence signals were used as outputs, combined with modular segmentation strategy of DNA-nanoswitch-based reaction platform; the multi-channel detection of up to ten targets was successfully achieved for the first time. The experimental results suggest that the proposed biosensor is a promising tool for simultaneously detecting multiple biomarkers for the early diagnosis of ovarian cancer, offering new strategies for the early screening, diagnosis, and treatment not only for ovarian cancer but also for other cancers.

Perspectives of primary care providers regarding multicancer early detection panels.

OBJECTIVE: Multicancer early detection panels have recently become available to patients with healthcare provider prescriptions and available funds. These tests utilize circulating tumor DNA (ctDNA) to screen more than 50 cancers using a single blood sample. However, perspectives and data on how the deployment of these tests may impact the practices of primary care providers in terms of implementation, interpretation, documentation, and costs are limited. This study aimed to assess the perspectives of primary care providers regarding the integration of multicancer early detection panels into clinical practice. METHODS: We used a survey to assess the opinions and perspectives of primary care providers, including physicians, nurse practitioners, and physician assistants, across a multistate, tertiary healthcare system. We used a single form consisting of novel questions on familiarity with multi-cancer early detection panels, cost, healthcare equity, documentation, medicolegal, and other concerns. The subgroup analysis was consistent with stratification based on familiarity with ctDNA-based tests and their roles in clinical practice. RESULTS: Most respondents were unfamiliar with multicancer early detection panels and had not used ctDNA-based tests. Most primary care providers suggested that they would reorder multicancer early detection panel testing at 1- to 5-year intervals and prefer subspecialists for both ordering multicancer early detection panels as well as interpreting their results. Relative concerns differed between physicians and nonphysicians. CONCLUSION: The integration of multicancer early detection panels into primary care practice requires careful planning and consideration for the management of increased clinical load, interpretation of results, and cost management.

Cell-free DNA from germline TP53 mutation carriers reflect cancer-like fragmentation patterns.

Germline pathogenic TP53 variants predispose individuals to a high lifetime risk of developing multiple cancers and are the hallmark feature of Li-Fraumeni syndrome (LFS). Our group has previously shown that LFS patients harbor shorter plasma cell-free DNA fragmentation; independent of cancer status. To understand the functional underpinning of cfDNA fragmentation in LFS, we conducted a fragmentomic analysis of 199 cfDNA samples from 82 TP53 mutation carriers and 30 healthy TP53-wildtype controls. We find that LFS individuals exhibit an increased prevalence of A/T nucleotides at fragment ends, dysregulated nucleosome positioning at p53 binding sites, and loci-specific changes in chromatin accessibility at development-associated transcription factor binding sites and at cancer-associated open chromatin regions. Machine learning classification resulted in robust differentiation between TP53 mutant versus wildtype cfDNA samples (AUC-ROC = 0.710-1.000) and intra-patient longitudinal analysis of ctDNA fragmentation signal enabled early cancer detection. These results suggest that cfDNA fragmentation may be a useful diagnostic tool in LFS patients and provides an important baseline for cancer early detection.

Clinical Validity and Utility of Circulating Tumor DNA (ctDNA) Testing in Advanced Non-small Cell Lung Cancer (aNSCLC): A Systematic Literature Review and Meta-analysis.

PURPOSE: Circulating tumor DNA (ctDNA) testing has become a promising tool to guide first-line (1L) targeted treatment for advanced non-small cell lung cancer (aNSCLC). This study aims to estimate the clinical validity (CV) and clinical utility (CU) of ctDNA-based next-generation sequencing (NGS) for oncogenic driver mutations to inform 1L treatment decisions in aNSCLC through a systematic literature review and meta-analysis. METHODS: A systematic literature search was conducted in PubMed/MEDLINE and Embase to identify randomized control trials or observational studies reporting CV/CU on ctDNA testing in patients with aNSCLC. Meta-analyses were performed using bivariate random-effects models to estimate pooled sensitivity and specificity. Progression-free/overall survival (PFS/OS) was summarized for CU studies. RESULTS: A total of 20 studies were identified: 17 CV only, 2 CU only, and 1 both, and 13 studies were included for the meta-analysis on multi-gene detection. The overall sensitivity and specificity for ctDNA detection of any mutation were 0.69 (95% CI 0.63-0.74) and 0.99 (95% CI 0.97-1.00), respectively. However, sensitivity varied greatly by driver gene, ranging from 0.29 (95% CI 0.13-0.53) for ROS1 to 0.77 (95% CI 0.63-0.86) for KRAS. Two studies that compared PFS with ctDNA versus tissue-based testing followed by 1L targeted therapy found no significant differences. One study reported OS curves on ctDNA-matched and tissue-matched therapies but no hazard ratios were provided. CONCLUSIONS: ctDNA testing demonstrated an overall acceptable diagnostic accuracy in patients with aNSCLC, however, sensitivity varied greatly by driver mutation. Further research is needed, especially for uncommon driver mutations, to better understand the CU of ctDNA testing in guiding targeted treatments for aNSCLC.

Excitation/emission-enhanced heterostructure photonic crystal array synergizing with "DD-A" FRET entropy-driven circuit for high-resolution and ultrasensitive analysis of ctDNA.

Circulating tumor DNA (ctDNA) is an emerging biomarker of liquid biopsy for cancer. But it remains a challenge to achieve simple, sensitive and specific detection of ctDNA because of low abundance and single-base mutation. In this work, an excitation/emission-enhanced heterostructure photonic crystal (PC) array synergizing with entropy-driven circuit (EDC) was developed for high-resolution and ultrasensitive analysis of ctDNA. The donor donor-acceptor FÖrster resonance energy transfer ("DD-A" FRET) was integrated in EDC based on the introduction of simple auxiliary strand, which exhibited higher sensitivity than that of traditional EDC. The heterostructure PC array was constructed with the bilayer periodic nanostructures of nanospheres. Because the heterostructure PC has the adjustable dual photonic band gaps (PBGs) by changing nanosphere sizes, and the "DD-A" FRET can offer the excitation and emission peak with enough distance, it helps the successful matches between the dual PBGs of heterostructure PC and the excitation/emission peaks of "DD-A" FRET; thus, the fluorescence from EDC can be enhanced effectively from both of excitation and emission processes on heterostructure PC array. Besides, high-resolution of single-base mutation was obtained through the strict recognition of EDC. Benefiting from the specific spectrum-matched and synergetic amplification of heterostructure PC and EDC with "DD-A" FRET, the proposed array obtained ultrasensitive detection of ctDNA with LOD of 12.9 fM, and achieved the analysis of mutation frequency as low as 0.01%. Therefore, the proposed strategy has the advantages of simple operation, mild conditions (enzyme-free and isothermal), high-sensitivity, high-resolution and high-throughput analysis, showing potential in bioassay and clinical application.

Identifying key circulating tumor DNA parameters for predicting clinical outcomes in metastatic non-squamous non-small cell lung cancer after first-line chemoimmunotherapy.

Circulating tumor DNA (ctDNA) provides valuable tumor-related information without invasive biopsies, yet consensus is lacking on optimal parameters for predicting clinical outcomes. Utilizing longitudinal ctDNA data from the large phase 3 IMpower150 study (NCT02366143) of atezolizumab in combination with chemotherapy with or without bevacizumab in patients with stage IV non-squamous Non-Small Cell Lung Cancer (NSCLC), here we report that post-treatment ctDNA response correlates significantly with radiographic response. However, only modest concordance is identified, revealing that ctDNA response is likely not a surrogate for radiographic response; both provide distinct information. Various ctDNA metrics, especially early ctDNA nadirs, emerge as primary predictors for progression-free survival and overall survival, potentially better assessing long-term benefits for chemoimmunotherapy in NSCLC. Integrating radiographic and ctDNA assessments enhances prediction of survival outcomes. We also identify optimal cutoff values for risk stratification and key assessment timepoints, notably Weeks 6-9, for insights into clinical outcomes. Overall, our identified optimal ctDNA parameters can enhance the prediction of clinical outcomes, refine trial designs, and inform therapeutic decisions for first-line NSCLC patients.

Kinetic Profiling of RAS Mutations With Circulating Tumor DNA in the Canadian Cancer Trials Group CO.26 Trial Suggests the Loss of RAS Mutations in Neo-RAS-Wildtype Metastatic Colorectal Cancer Is Transient.

PURPOSE: In metastatic colorectal cancer (mCRC), RAS mutations drive resistance to anti-epidermal growth factor receptor antibodies. It is unclear whether RAS mutations ever become clonally undetectable. METHODS: CO.26 was a phase II clinical trial that assessed durvalumab + tremelimumab in heavily pretreated mCRC. RAS mutation status was tracked over time using circulating tumor DNA (ctDNA) sequencing at baseline, week 8, and on progression. RESULTS: Among the 95 patients with KRAS/NRAS mutations in their archival tumor tissue, 6.3% (6/95) had undetectable RAS mutations in ctDNA collected at baseline or week 8 of the CO.26 study. Of these, 67% (4/6) of disappearances were transient, with the same mutation reappearing with progressive disease. In three cases, the simultaneous persistence of other preexisting CRC-associated truncal mutations could not be demonstrated, suggestive of low tumor shedding of ctDNA, leaving the incidence of true clonal reversion to RAS-wildtype (WT) possibly as low as 3.2% (3/95). Fewer patients in the neo-RAS-WT group (33%) had greater than four lesions at trial baseline compared with patients with persistent RAS mutations (75%), P = .046. The likelihood of synchronous metastases at cancer diagnosis (33% v 63%; P = .15) or liver metastases at trial baseline (50% v 68.5%; P = .17) was not significantly different between patients with disappearing versus persistent RAS mutations. Overall survival from stage IV diagnosis (hazard ratio, 0.77 [95% CI, 0.35 to 1.72]; P = .52) was not significantly different between those with disappearing versus persistent RAS mutations. The disappearance of RAS mutations was not associated with primary tumor sidedness (P = .41), archival BRAF/MEK/ERK-mutant status (P = .16/1.00/.09), nor baseline ctDNA HER2 amplifications (P = 1.00). CONCLUSION: We identified a 3.2%-6.3% prevalence of the neo-RAS-WT phenomenon in the CO.26 trial. However, 67% of apparent cases were transient with subsequent re-emergence.

Combined Transcriptome and Circulating Tumor DNA Longitudinal Biomarker Analysis Associates With Clinical Outcomes in Advanced Solid Tumors Treated With Pembrolizumab.

PURPOSE: Immune gene expression signatures are emerging as potential biomarkers for immunotherapy (IO). VIGex is a 12-gene expression classifier developed in both nCounter (Nanostring) and RNA sequencing (RNA-seq) assays and analytically validated across laboratories. VIGex classifies tumor samples into hot, intermediate-cold (I-Cold), and cold subgroups. VIGex-Hot has been associated with better IO treatment outcomes. Here, we investigated the performance of VIGex and other IO biomarkers in an independent data set of patients treated with pembrolizumab in the INSPIRE phase II clinical trial (ClinicalTrials.gov identifier: NCT02644369). MATERIALS AND METHODS: Patients with advanced solid tumors were treated with pembrolizumab 200 mg IV once every 3 weeks. Tumor RNA-seq data from baseline tumor samples were classified by the VIGex algorithm. Circulating tumor DNA (ctDNA) was measured at baseline and start of cycle 3 using the bespoke Signatera assay. VIGex-Hot was compared with VIGex I-Cold + Cold and four groups were defined on the basis of the combination of VIGex subgroups and the change in ctDNA at cycle 3 from baseline (ΔctDNA). RESULTS: Seventy-six patients were enrolled, including 16 ovarian, 12 breast, 12 head and neck cancers, 10 melanoma, and 26 other tumor types. Objective response rate was 24% in VIGex-Hot and 10% in I-Cold/Cold. VIGex-Hot subgroup was associated with higher overall survival (OS) and progression-free survival (PFS) when included in a multivariable model adjusted for tumor type, tumor mutation burden, and PD-L1 immunohistochemistry. The addition of ΔctDNA improved the predictive performance of the baseline VIGex classification for both OS and PFS. CONCLUSION: Our data indicate that the addition of ΔctDNA to baseline VIGex may refine prediction for IO.

Analysis of the effect of baseline detection and early clearance of ct-DNA, on survival outcomes among patients with advanced EGFR-mutant non-small cell lung cancer.

BACKGROUND: To determine if circulating tumor DNA (ct-DNA) dynamics of epidermal growth factor receptor (EGFR) mutation in plasma can identify a subset of patients with EGFR-mutant (EGFR- m) non-small cell lung cancer (NSCLC) with inferior survival outcomes, we analyzed and compared survival outcomes among patients with and without baseline presence and early clearance of EGFR ct-DNA in plasma. MATERIAL AND METHODS: For 66 patients newly dia-gnosed with EGFR- m NSCLC, plasma samples were collected at baseline and 1st response assessment at 12-24 weeks for extraction of ct-DNA. Estimation of ct-DNA (EGFR exons 18, 19, 20 and 21) was done using droplet digital polymerase chain reaction (dd-PCR) on the QX200 ddPCR system (BioRad, USA). Patients with detectable EGFR ct-DNA at baseline (sample 1), with either undetectable or persistent detectable ct-DNA in sample 2 were classified as clearers and non-clearers, respectively. RESULTS: Fifty-three patients received 1st/ 2nd generation EGFR tyrosine kinase inhibitors (TKIs) and 13 received either 3rd generation TKI (osimertinib) or chemotherapy plus gefitinib. The baseline ct-DNA-positive group had more patients with extra thoracic disease (60.4 vs. 48.5%). For the entire cohort, there was no difference in median progression-free survival (PFS) among baseline ct-DNA-negative (13.57 months) vs. ct-DNA-positive patients (12.32 months) (HR 0.74). There was a significant improvement of PFS among early ct-DNA clearers vs. non-clearers (12.32 vs. 9.92 months; HR 0.57). For those treated with 1st/ 2nd generation EGFR TKIs, this improvement in median PFS among early ct-DNA clearers vs. non-clearers was more apparent (11.76 vs. 6.8 months; HR 0.34). CONCLUSIONS: Baseline detection of the presence of ct-DNA of EGFR mutation in plasma was not predictive of first-line PFS, but is associated with extra thoracic disease. Patients with EGFR mutation and persistence of ct-DNA at first follow-up have worse PFS and overall survival (OS) in comparison to those clearing the same in plasma, especially among those treated with 1st/ 2nd generation EGFR TKIs.

The landscape of circulating tumor HPV DNA and TTMV-HPVDNA for surveillance of HPV-oropharyngeal carcinoma: systematic review and meta-analysis.

BACKGROUND: Human papilloma virus (HPV) related cancers of the oropharynx are rapidly increasing in incidence and may soon represent the majority of all head and neck cancers. Improved monitoring and surveillance methods are thus an urgent need in public health. MAIN TEXT: The goal is to highlight the current potential and limitations of liquid biopsy through a meta analytic study on ctHPVDNA and TTMV-HPVDNA. It was performed a Literature search on articles published until December 2023 using three different databases: MEDLINE, Embase, and Cochrane Library. Studies that evaluated post-treatment ctHPVDNA and TTMV-HPVDNA in patients with HPV + OPSCC, studies reporting complete data on the diagnostic accuracy in recurrence, or in which the number of true positives, false positives, true negatives, and false negatives was extractable, and methods of detection of viral DNA clearly defined. The meta-analysis was conducted following the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) reporting guidelines. The aim of this meta-analysis was to evaluate the sensitivity, specificity, and accuracy of ctHPVDNA and TTMV by ddPCR to define its efficacy in clinical setting for the follow up of HPV-OPSCC. CONCLUSION: The 12 studies included in the meta-analysis provided a total of 1311 patients for the analysis (398 valuated with ctHPVDNA and 913 with TTMV-HPVDNA). Pooled sensitivity and specificity were 86% (95% CI: 78%-91%) and 96% (95% CI: 91%-99%), respectively; negative and positive likelihood ratios were 0.072 (95% CI: 0.057-0.093) and 24.7 (95% CI: 6.5-93.2), respectively; pooled DOR was 371.66 (95% CI: 179.1-918). The area under the curve (AUC) was 0.81 (95% CI, 0.67-0.91). Liquid biopsy for the identification of cell free DNA might identify earlier recurrence in HPV + OPSCC patients. At the present time, liquid biopsy protocol needs to be standardized and liquid biopsy cannot yet be used in clinical setting. In the future, a multidimensional integrated approach which links multiple clinical, radiological, and laboratory data will contribute to obtain the best follow-up strategies for the follow-up of HPV-OPSCC.

Patient-centric thresholding of Cobas® EGFR mutation Test v2 for surveillance of EGFR-mutated metastatic non-small cell lung cancer.

Cobas EGFR mutation Test v2 was FDA-approved as qualitative liquid biopsy for actionable EGFR variants in non-small cell lung cancer (NSCLC). It generates semiquantitative index (SQI) values that correlate with mutant allele levels, but decision thresholds for clinical use in NSCLC surveillance are lacking. We conducted long-term ctDNA monitoring in 20 subjects with EGFR-mutated NSCLC; resulting in a 155 on-treatment samples. We defined optimal SQI intervals to predict/rule-out progression within 12 weeks from sampling and performed orthogonal calibration versus deep-sequencing and digital PCR. SQI showed significant diagnostic power (AUC 0.848, 95% CI 0.782-0.901). SQI below 5 (63% of samples) had 93% (95% CI 87-96%) NPV, while SQI above 10 (25% of samples) had 69% (95% CI 56-80%) PPV. Cobas EGFR showed perfect agreement with sequencing (Kappa 0.860; 95% CI 0.674-1.00) and digital PCR. SQI values strongly (r: 0.910, 95% 0.821-0.956) correlated to mutant allele concentrations with SQI of 5 and 10 corresponding to 6-9 (0.2-0.3%) and 64-105 (1.1-1.6%) mutant allele copies/mL (VAF) respectively. Our dual-threshold classifier of SQI 0/5/10 yielded informative results in 88% of blood draws with high NPV and good overall clinical utility for patient-centric surveillance of metastatic NSCLC.

Clinical features associated with NeoRAS wild-type metastatic colorectal cancer A SCRUM-Japan GOZILA substudy.

"NeoRAS WT" refers to the loss of RAS mutations (MTs) following first-line treatment in metastatic colorectal cancer (mCRC). We evaluate the incidence and clinicopathological characteristics of NeoRAS WT mCRC using next-generation sequencing of plasma circulating tumor DNA. Patients with mCRC enrolled in the GOZILA study initially diagnosed with tissue RAS MT mCRC and received subsequent systemic therapy are eligible. NeoRAS WT is defined as the absence of detectable RAS MT in plasma and assessed in all eligible patients (Group A) and in a subgroup with at least one somatic alteration detected in plasma (Group B). Overall, 478 patients are included. NeoRAS WT prevalence is 19.0% (91/478) in Group A and 9.8% (42/429) in Group B. Absence of liver or lymph node metastasis and tissue RAS MTs other than KRAS exon 2 MTs are significantly associated with NeoRAS WT emergence. Overall, 1/6 and 2/6 patients with NeoRAS WT treated with anti-EGFR monoclonal antibodies (mAbs) show partial response and stable disease for ≥6 months, respectively. NeoRAS WT mCRC is observed at a meaningful prevalence, and anti-EGFR mAb-based therapy may be effective.

Circulating KRAS G12D but not G12V is associated with survival in metastatic pancreatic ductal adenocarcinoma.

While high circulating tumor DNA (ctDNA) levels are associated with poor survival for multiple cancers, variant-specific differences in the association of ctDNA levels and survival have not been examined. Here we investigate KRAS ctDNA (ctKRAS) variant-specific associations with overall and progression-free survival (OS/PFS) in first-line metastatic pancreatic ductal adenocarcinoma (mPDAC) for patients receiving chemoimmunotherapy ("PRINCE", NCT03214250), and an independent cohort receiving standard of care (SOC) chemotherapy. For PRINCE, higher baseline plasma levels are associated with worse OS for ctKRAS G12D (log-rank p = 0.0010) but not G12V (p = 0.7101), even with adjustment for clinical covariates. Early, on-therapy clearance of G12D (p = 0.0002), but not G12V (p = 0.4058), strongly associates with OS for PRINCE. Similar results are obtained for the SOC cohort, and for PFS in both cohorts. These results suggest ctKRAS G12D but not G12V as a promising prognostic biomarker for mPDAC and that G12D clearance could also serve as an early biomarker of response.