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Supplemental Table 1 - Assayed Genes on the Oncoscan Assay Supplemental Table 2 - Total list of CNVs for Case 1 and Case 2 Supplemental Table 3 - List of CNVs Filtered by COSMIC Database for Cases 1-7 Supplemental Figure 1 - Quantitative PCR Validation of EGFR Identification

Purpose: There is a growing interest in using circulating tumor DNA (ctDNA) testing in patients with cancer.Experimental Design: A total of 168 patients with diverse cancers were analyzed. Patients had digital next-generation sequencing (54 cancer-related gene panel including amplifications in ERBB2, EGFR, and MET) performed on their plasma. Type of genomic alterations, potential actionability, concordance with tissue testing, and patient outcome were examined.Results: Fifty-eight percent of patients (98/168) had ≥1 ctDNA alteration(s). Of the 98 patients with alterations, 71.4% had ≥ 1 alteration potentially actionable by an FDA-approved drug. The median time interval between the tissue biopsy and the blood draw was 2.7 months for patients with ≥ 1 alteration in common compared with 14.4 months (P = 0.006) for the patients in whom no common alterations were identified in the tissue and plasma. Overall concordance rates for tissue and ctDNA were 70.3% for TP53 and EGFR, 88.1% for PIK3CA, and 93.1% for ERBB2 alterations. There was a significant correlation between the cases with ≥ 1 alteration with ctDNA ≥ 5% and shorter survival (median = 4.03 months vs. not reached at median follow-up of 6.1 months; P < 0.001). Finally, 5 of the 12 evaluable patients (42%) matched to a treatment targeting an alteration(s) detected in their ctDNA test achieved stable disease ≥ 6 months/partial remission compared with 2 of 28 patients (7.1%) for the unmatched patients, P = 0.02.Conclusions: Our initial study demonstrates that ctDNA tests provide information complementary to that in tissue biopsies and may be useful in determining prognosis and treatment. Clin Cancer Res; 22(22); 5497–505. ©2016 AACR.

Urine volumes, DNA concentrations, DNA input amounts, the number of output mutant sequencing reads, mutant copies detected and the 95% Confidence Intervals

EGFR-activating mutations are observed in approximately 15% to 20% of patients with non–small cell lung cancer. Tyrosine kinase inhibitors have provided an illustrative example of the successes in targeting oncogene addiction in cancer and the role of tumor-specific adaptations conferring therapeutic resistance. The compound osimertinib is a third-generation tyrosine kinase inhibitor, which was granted full FDA approval in March 2017 based on targeting EGFR T790M resistance. The compound has received additional FDA approval as first-line therapy with improvement in progression-free survival by suppressing the activating mutation and preventing the rise of the dominant resistance clone. Drug development has been breathtaking in this space with other third-generation compounds at various stages of development: rociletinib (CO-1686), olmutinib (HM61713), nazartinib (EGF816), naquotinib (ASP8273), mavelertinib (PF-0647775), and AC0010. However, therapeutic resistance after the administration of third-generation inhibitors is complex and not fully understood, with significant intertumoral and intratumoral heterogeneity. Repeat tissue and plasma analyses on therapy have revealed insights into multiple mechanisms of resistance, including novel second site EGFR mutations, activated bypass pathways such as MET amplification, HER2 amplification, RAS mutations, BRAF mutations, PIK3CA mutations, and novel fusion events. Strategies to understand and predict patterns of mutagenesis are still in their infancy; however, technologies to understand synthetically lethal dependencies and track cancer evolution through therapy are being explored. The expansion of combinatorial therapies is a direction forward targeting minimal residual disease and bypass pathways early based on projected resistance.

Purpose: Noninvasive drug biomarkers for the early assessment of tumor response can enable adaptive therapeutic decision-making and proof-of-concept studies for investigational drugs. Circulating tumor DNA (ctDNA) is released into the circulation by tumor cell turnover and has been shown to be detectable in urine.Experimental Design: We tested the hypothesis that dynamic changes in EGFR activating (exon 19del and L858R) and resistance (T790M) mutation levels detected in urine could inform tumor response within days of therapy for advanced non–small cell lung cancer (NSCLC) patients receiving osimertinib, a second-line third-generation anti-EGFR tyrosine kinase inhibitor.Results: Eight of nine evaluable NSCLC patients had detectable T790M-mutant DNA fragments in pretreatment baseline samples. Daily monitoring of mutations in urine indicated a pattern of intermittent spikes throughout week 1, suggesting apoptosis with an overall decrease in fragment numbers from baselines to day 7 preceding radiographic response assessed at 6 to 12 weeks.Conclusions: These findings suggest drug-induced tumor apoptosis within days of initial dosing. Daily sampling of ctDNA may enable early assessment of patient response and proof-of-concept studies for drug development. The modeling of tumor lysis through the day-to-day kinetics of ctDNA released into the blood and then into the urine is demonstrated in this proof-of-concept study in lung cancer patients receiving anti-EGFR tyrosine kinase inhibitors. This strategy may determine the specific clonal populations of cells which undergo apoptosis within the first week of therapy. This has important implications for developing combinational strategies to address inter- and intralesional heterogeneity and characterizing residual disease after initial drug exposure. Clin Cancer Res; 23(16); 4716–23. ©2017 AACR.

Clinical Outcomes with Various Third Generation EGFR Inhibitors

A: Analysis of dilution series of indicated mutant EGFR variants spiked into 60 ng (â‰^18,180 genome equivalents) of WT DNA. Each data point represents one preparative within 6 independent dilutions series prepared and analyzed by two operators on two different instruments on three non-consecutive days for a total of 18 samples per dilution point. An analysis algorithm was applied to transform the mutant EGFR sequencing reads into the absolute mutant copies detected. The box-and-whisker plots show the median (center line), 25th and 75th percentiles (box) with the connecting "whiskers" extending from the first quartile minus 1.5 of the interquartile range (IQR, the third quartile less the first quartile) and the third quartile plus 1.5 of the IQR. A positive Spearman's correlation close to 1 indicates a strong, positive relationship between the absolute mutant EGFR copies detected and the absolute mutant EGFR copies per input. B: Inter-run reproducibility of the EGFR exon 19 deletions, L858R and T790M enrichment PCR-NGS assays for the dilution series shown in panel A. The Coefficient of Variation Percent (CV%) was calculated as the ratio of the standard deviation to the mean of the absolute EGFR copies detected within each absolute copy per input level and is reported as a percentage.

The supplementary tables for "Early noninvasive detection of response to targeted therapy in non-small cell lung cancer" report clinical characteristics of patients analyzed (1), serial timepoints analyzed (2), genes analyzed (3), a summary of genomic analyses (4), somatic sequence alterations detected in cfDNA (5), somatic structural alterations detected in cfDNA (6), and blood cell proliferation alterations detected in cfDNA (7).

Supplemental Table 1. Guardant360 54 gene cell-free DNA NGS panel. Complete exon coverage for genes in bold. Unbolded genes had critical exon coverage. Supplemental Table 2. Frequency of patients with metastatic/recurrent/advanced unresectable disease Supplemental Table 3. List of the 12 evaluable patients treated with a matched therapy targeting {greater than or equal to} 1 alteration detected by the ctDNA test. Supplemental Figure 1. Diagram of the population analyzed for treatment outcome

Purpose: Genomic alterations in blood-derived circulating tumor DNA (ctDNA) from patients with non–small cell lung adenocarcinoma (NSCLC) were ascertained and correlated with clinical characteristics and therapeutic outcomes.Experimental Design: Comprehensive plasma ctDNA testing was performed in 88 consecutive patients; 34 also had tissue next-generation sequencing; 29, other forms of genotyping; and 25 (28.4%) had no tissue molecular tests because of inadequate tissue or biopsy contraindications.Results: Seventy-two patients (82%) had ≥1 ctDNA alteration(s); among these, 75% carried alteration(s) potentially actionable by FDA-approved (61.1%) or experimental drug(s) in clinical trials (additional 13.9%). The most frequent alterations were in the TP53 (44.3% of patients), EGFR (27.3%), MET (14.8%), KRAS (13.6%), and ALK (6.8%) genes. The concordance rate for EGFR alterations was 80.8% (100% vs. 61.5%; ≤1 vs. >1 month between ctDNA and tissue tests; P = 0.04) for patients with any detectable ctDNA alterations. Twenty-five patients (28.4%) received therapy matching ≥1 ctDNA alteration(s); 72.3% (N = 16/22) of the evaluable matched patients achieved stable disease ≥6 months (SD) or partial response (PR). Five patients with ctDNA-detected EGFR T790M were subsequently treated with a third generation EGFR inhibitor; all five achieved SD ≥ 6 months/PR. Patients with ≥1 alteration with ≥5% variant allele fraction (vs. < 5%) had a significantly shorter median survival (P = 0.012).Conclusions: ctDNA analysis detected alterations in the majority of patients, with potentially targetable aberrations found at expected frequencies. Therapy matched to ctDNA alterations demonstrated appreciable therapeutic efficacy, suggesting clinical utility that warrants future prospective studies. Clin Cancer Res; 23(17); 5101–11. ©2017 AACR.

Shows the 3 ctDNA panels, the list of alterations identified, the concordance analysis for EGFR, and a diagram on response evaluation

Chemical Structures of Third Generation Anti-EGFR Compounds

EGFR Receptor Signaling and Bypass Pathways

The supplementary figures for "Early noninvasive detection of response to targeted therapy in non-small cell lung cancer" depict dynamic changes of ctDNA during therapy (S1), copy number changes identified in cfDNA from analyses of whole-genome data (S2), concordance between alterations observed with TEC-Seq in the plasma and clinical NGS analyses in the tumor tissue or plasma (S3), timeline of ctDNA analyses, CT assessments, and treatment response (S4), CT imaging assessments for responders and non-responders (S5), and cell-free tumor load and change in RECIST SLD (S6) for patients analyzed.

With the advent of precision oncology, there is an urgent need to develop improved methods for rapidly detecting responses to targeted therapies. Here, we have developed an ultrasensitive measure of cell-free tumor load using targeted and whole-genome sequencing approaches to assess responses to tyrosine kinase inhibitors in patients with advanced lung cancer. Analyses of 28 patients treated with anti-EGFR or HER2 therapies revealed a bimodal distribution of cell-free circulating tumor DNA (ctDNA) after therapy initiation, with molecular responders having nearly complete elimination of ctDNA (>98%). Molecular nonresponders displayed limited changes in ctDNA levels posttreatment and experienced significantly shorter progression-free survival (median 1.6 vs. 13.7 months, P < 0.0001; HR = 66.6; 95% confidence interval, 13.0–341.7), which was detected on average 4 weeks earlier than CT imaging. ctDNA analyses of patients with radiographic stable or nonmeasurable disease improved prediction of clinical outcome compared with CT imaging. These analyses provide a rapid approach for evaluating therapeutic response to targeted therapies and have important implications for the management of patients with cancer and the development of new therapeutics.Significance: Cell-free tumor load provides a novel approach for evaluating longitudinal changes in ctDNA during systemic treatment with tyrosine kinase inhibitors and serves an unmet clinical need for real-time, noninvasive detection of tumor response to targeted therapies before radiographic assessment.See related commentary by Zou and Meyerson, p. 1038

IntroductionEGFR mutations drive a subset of NSCLC. Patients harboring the common EGFR mutations, deletion ofexon 19 and L858R, respond well to osimertinib, a third-generation tyrosine kinase inhibitor. Nevertheless, the effect of osimertinib on NSCLC with atypical EGFR mutations is not well described. This multicenter retrospective study evaluates the efficacy of osimertinib among patients with NSCLC harboring atypical EGFR mutations.MethodsPatients with metastatic NSCLC treated with osimertinib, harboring at least one atypical EGFR mutation, excluding concurrent deletion of exon 19, L858R, or T790M mutations, from six U.S. academic cancer centers were included. Baseline clinical characteristics were collected. The primary end point was the time to treatment discontinuation (TTD) of osimertinib. Objective response rate by the Response Evaluation Criteria in Solid Tumors version 1.1 was also assessed.ResultsA total of 50 patients with NSCLC with uncommon EGFR mutations were identified. The most frequent EGFR mutations were L861Q (40%, n= 18), G719X (28%, n= 14), and exon 20 insertion (14%, n= 7). The median TTD of osimertinib was 9.7 months (95% confidence interval [CI]: 6.5-12.9 mo) overall and 10.7 months (95% CI: 3.2-18.1 mo) in the first-line setting (n= 20). The objective response rate was 31.7% (95% CI: 18.1%-48.1%) overall and 41.2% (95% CI: 18.4%-67.1%) in the first-line setting. The median TTD varied among patients with L861Q (17.2 mo), G719X (7.8 mo), and exon 20 insertion (1.5 mo) mutations.ConclusionsOsimertinib has activity in patients with NSCLC harboring atypical EGFR mutations. Osimertinib activity differs by the type of atypical EGFR-activating mutation.

PURPOSE Profiling of circulating tumor DNA (ctDNA) is increasingly adopted in the management of solid tumors, concurrent with increased availability of more comprehensive ctDNA panels. However, variable ctDNA shed can result in variable assay sensitivity. We studied the relationship between ctDNA tumor fraction (TF) and detection of actionable alterations across cancer types. METHODS A total of 23,482 liquid biopsies (LBx) submitted between September 2020 and October 2021 were sequenced using a hybrid capture panel that reports genomic alterations (GAs) and genomic biomarkers across 324 cancer-related genes. The primary end points were the prevalence of targetable GAs by cancer type and detection in relationship to ctDNA TF. Sensitivity of detection in LBx was assessed in 1,289 patients with available tissue results. RESULTS 94% (n = 22,130) of LBx had detectable ctDNA, with a median TF of 2.2%. LBx profiling detected GAs in National Comprehensive Cancer Network category 1 genes in 37% of lung, 30% of prostate, 36% of breast, and 51% of colon cancer cases. Potential germline GAs flagged on clinical reports were detected in genes including BRCA1/2, PALB2, CHEK2, and ATM. Polyclonal mutations in genes associated with resistance such as AR, ESR1, RB1, and NF1 were detected. The sensitivity of LBx to detect driver alterations identified in tissue biopsy from the same patient ranged from 58% to 86% but was consistently at or near 100% in cases with TF ≥ 10%. CONCLUSION Elevated ctDNA shed is associated with both high sensitivity and negative predictive value for detection of actionable GAs. The presence of elevated TF suggests adequate tumor profiling and may reduce the value of subsequent reflex to confirmatory tissue testing in patients with negative LBx results.

Analyses of cell-free tumor DNA (ctDNA) have provided a non-invasive strategy for cancer diagnosis, the identification of molecular aberrations for treatment identification, and evaluation of tumor response. Sensitive and specific ctDNA sequencing strategies have allowed for implementation into clinical practice for the initial genotyping of patients and resistance monitoring. The specific need for EGFR mutation detection for the management of lung cancer patients has been an early imperative and has set the stage for non-invasive molecular profiling across other oncogenic drivers. Ongoing efforts are demonstrating the utility of ctDNA analyses in the initial genotyping of patients, the monitoring resistance clones, and the initial evaluation of response.

BACKGROUND: Anlotinib demonstrated improved overall survival (OS) and progression-free survival (PFS) compared with placebo as a third-line or subsequent therapy in patients with non-small cell lung cancer (NSCLC) in the ALTER0303 trial. The status of epidermal growth factor receptor (EGFR) mutation, different previous treatment may affect the efficacy of subsequent therapy, and we did this subgroup analysis to characterize the efficacy of anlotinib in patients with and without EGFR mutation. METHODS: The ALTER0303 trial was a randomized, double-blind, phase 3 study of anlotinib in patients with NSCLC who failed at least 2 lines of treatment. In the study, 138 of 437 randomized patients were EGFR mutation positive. A Cox model was used to examine the influence of previous treatment on the efficacy of anlotinib according to EGFR mutation status. RESULTS: For patients with EGFR mutation, the OS was 10.7 and 6.3 months (HR 0.59; 95% CI: 0.38–0.94, P=0.025) in the anlotinib and placebo group, respectively. The PFS was 5.6 and 0.8 months (HR 0.21; 95% CI: 0.13–0.32, P

This Phase 1/2 study (NCT02349633) explored the safety and antitumor activity of PF-06747775 (oral, third-generation epidermal growth factor receptor [EGFR] tyrosine kinase inhibitor) in patients with advanced non-small cell lung cancer after progression on an EGFR inhibitor. Phase 1 was a dose-escalation study of PF-06747775 monotherapy (starting dose: 25 mg once daily [QD]). Phase 1b/2 evaluated PF-06747775 monotherapy at recommended Phase 2 dose (RP2D; Cohort 1); PF-06747775 200 mg QD plus palbociclib (starting dose: 100 mg QD orally; Cohort 2A); and PF-06747775 monotherapy at RP2D in a Japanese lead-in cohort. Sixty-five patients were treated. Median treatment duration was 40.1 weeks. Monotherapy maximum tolerated dose was not determined. Two patients in Cohort 2A had dose-limiting toxicities. The monotherapy RP2D was estimated to be 200 mg QD. Most frequently reported adverse events (AEs) were diarrhea (69.2%), paronychia (69.2%), and rash (60.0%). Most AEs were grades 1–3. Overall, objective response rate (90% confidence interval [CI]) was 41.5% (31.2–52.5%). Median (range) duration of response was 11.09 (2.70–34.57) months. Median progression-free survival (90% CI) was 8.1 (5.4–23.3) months. PF-06747775 had a manageable safety profile and the study design highlights important considerations for future anti-EGFR agent development.

BACKGROUND: KRAS gene mutations are the most common driver oncogenes in non-small cell lung cancer (NSCLC). We conducted an analysis of the immunological characteristics including tumor mutation burden and programmed death-ligand 1 (PD-L1) expression of different subtypes of KRAS in 2880 KRAS-mutant NSCLC patients. METHODS: A total of 2,880 patients with NSCLC were included in the study. Somatic mutation data were provided by Berry Oncology (Fujian, China), Geneplus BioTech (Beijing, China), Nanjing Geneseeq Technology Inc (Nanjing, China), and Burning Rock Biotech (Guangzhou, China). Z-scores were used to unify all data. SPSS 20.0 (SPSS, Chicago, IL, USA) software was used for statistical analyses. All scatter plots and boxplot maps were drawn using GraphPad Prism 8. Tumor mutation burden (TMB) expression was defined by the number of somatic mutations. The PD-L1 clone 22C3 pharmDx kit was used to measure the expression level of PD-L1. Mann-Whitney U test was used for statistical analysis. P value

With the advent of precision oncology, there is an urgent need to develop improved methods for rapidly detecting responses to targeted therapies. Here, we have developed an ultrasensitive measure of cell-free tumor load using targeted and whole-genome sequencing approaches to assess responses to tyrosine kinase inhibitors in patients with advanced lung cancer. Analyses of 28 patients treated with anti-EGFR or HER2 therapies revealed a bimodal distribution of cell-free circulating tumor DNA (ctDNA) after therapy initiation, with molecular responders having nearly complete elimination of ctDNA (>98%). Molecular nonresponders displayed limited changes in ctDNA levels posttreatment and experienced significantly shorter progression-free survival (median 1.6 vs. 13.7 months, P < 0.0001; HR = 66.6; 95% confidence interval, 13.0–341.7), which was detected on average 4 weeks earlier than CT imaging. ctDNA analyses of patients with radiographic stable or nonmeasurable disease improved prediction of clinical outcome compared with CT imaging. These analyses provide a rapid approach for evaluating therapeutic response to targeted therapies and have important implications for the management of patients with cancer and the development of new therapeutics. Significance: Cell-free tumor load provides a novel approach for evaluating longitudinal changes in ctDNA during systemic treatment with tyrosine kinase inhibitors and serves an unmet clinical need for real-time, noninvasive detection of tumor response to targeted therapies before radiographic assessment. See related commentary by Zou and Meyerson, p. 1038

Background The usefulness of circulating tumor DNA (ctDNA) in detecting mutations and monitoring treatment response has not been well studied beyond a few actionable biomarkers in non-small cell lung cancer (NSCLC). Research Question How does the usefulness of ctDNA analysis compare with that of solid tumor biopsy analysis in patients with NSCLC? Methods We retrospectively evaluated 370 adult patients with NSCLC treated at the City of Hope between November 2015 and August 2019 to assess the usefulness of ctDNA in mutation identification, survival, concordance with matched tissue samples in 32 genes, and tumor evolution. Results A total of 1,688 somatic mutations were detected in 473 ctDNA samples from 370 patients with NSCLC. Of the 473 samples, 177 showed at least one actionable mutation with currently available Food and Drug Administration-approved NSCLC therapies. MET and CDK6 amplifications co-occurred with BRAF amplifications (false discovery rate [FDR], < 0.01), and gene-level mutations were mutually exclusive in KRAS and EGFR (FDR, 0.0009). Low cumulative percent ctDNA levels were associated with longer progression-free survival (hazard ratio [HR], 0.56; 95% CI, 0.37-0.85; P = .006). Overall survival was shorter in patients harboring BRAF mutations (HR, 2.35; 95% CI, 1.24-4.6; P = .009), PIK3CA mutations (HR, 2.77; 95% CI, 1.56-4.9; P < .001) and KRAS mutations (HR, 2.32; 95% CI, 1.30-4.1; P = .004). Gene-level concordance was 93.8%, whereas the positive concordance rate was 41.6%. More mutations in targetable genes were found in ctDNA than in tissue biopsy samples. Treatment response and tumor evolution over time were detected in repeated ctDNA samples. Interpretation Although ctDNA analysis exhibited similar usefulness to tissue biopsy analysis, more mutations in targetable genes were missed in tissue biopsy analyses. Therefore, the evaluation of ctDNA in conjunction with tissue biopsy samples may help to detect additional targetable mutations to improve clinical outcomes in advanced NSCLC.

Purpose Desmoplastic small round blue-cell tumors (DSRCTs) are sarcomas that contain the t(11;22) (p13;q12) translocation EWS-WT1 fusion protein. Because this is a rare tumor type, prospective clinical trials in DSRCT are challenging. Patients are treated in a manner similar to those with Ewing sarcoma; however, differences in prognosis and clinical presentation suggest fundamental differences in biology and potentially different therapeutic implications. This study aimed to characterize the molecular characteristics of DSRCT tumors to explore unique therapeutic options for this extremely rare and aggressive cancer type. Methods Thirty-five DSRCT tumors were assessed using next-generation sequencing, protein expression (immunohistochemistry), and gene amplification (chromogenic in situ hybridization or fluorescence in situ hybridization). Three patients had tumor mutational load, which was calculated as somatic nonsynonymous missense mutations sequenced with a 592-gene panel. Gene expression data were obtained for an additional seven DSRCT tumors. Molecular alterations were compared with 88 Ewing sarcomas. Results The most common alterations that distinguished DSRCTs from Ewing sarcoma included higher androgen receptor (AR), TUBB3, epidermal growth factor receptor, and TOPO2A expression. Independent analysis by RNA sequencing confirmed higher AR expression from an independent data set of EWS-WT1 fusion–positive DSRCTs compared with Ewing sarcoma and a pan-cancer analysis. DSRCTs had somatic mutations that were identified in TP53 and FOXO3, averaged five mutations per megabase, and no programmed death-ligand 1 expression was detected in any DSRCT samples. Conclusion The current analysis provides the first comparative analysis, to our knowledge, of molecular aberrations that distinguish DSRCT from Ewing sarcoma. High AR expression seems to be a defining event in these malignancies, and additional investigation of the responsiveness of AR inhibitors in this disease is encouraged.

A widespread approach to modern cancer therapy is to identify a single oncogenic driver gene and target its mutant-protein product (for example, EGFR-inhibitor treatment in EGFR-mutant lung cancers). However, genetically driven resistance to targeted therapy limits patient survival. Through genomic analysis of 1,122 EGFR-mutant lung cancer cell-free DNA samples and whole-exome analysis of seven longitudinally collected tumor samples from a patient with EGFR-mutant lung cancer, we identified critical co-occurring oncogenic events present in most advanced-stage EGFR-mutant lung cancers. We defined new pathways limiting EGFR-inhibitor response, including WNT/β-catenin alterations and cell-cycle-gene (CDK4 and CDK6) mutations. Tumor genomic complexity increases with EGFR-inhibitor treatment, and co-occurring alterations in CTNNB1 and PIK3CA exhibit nonredundant functions that cooperatively promote tumor metastasis or limit EGFR-inhibitor response. This study calls for revisiting the prevailing single-gene driver-oncogene view and links clinical outcomes to co-occurring genetic alterations in patients with advanced-stage EGFR-mutant lung cancer.

Collection of cell-free DNA (cfDNA) from the blood of individuals with cancer has permitted noninvasive tumor genome analysis. Detection and characterization of cfDNA in ascites and pleural effusions have not yet been reported. Herein, we analyzed cfDNA in the ascites and pleural effusions from six individuals with metastatic cancer. In all cases, cfDNA copy number variations (CNV) were discovered within the effusate. One individual had a relevant alteration with a high copy amplification in EGFR in a never smoker with lung cancer, who showed only MDM2 and CDK4 amplification in a prior tissue biopsy. Another subject with metastatic breast cancer had cytology-positive ascites and an activating PIK3CA mutation identified in the tissue, blood, and ascites collectively. This individual had tumor regression after the administration of the mTOR inhibitor everolimus and had evidence of chromotripsis from chromosomal rearrangements noted in the cell-free ascitic fluid. These results indicate that cfDNA from ascites and pleural effusions may provide additional information not detected with tumor and plasma cell-free DNA molecular characterization, and a context for important insights into tumor biology and clonal dynamic change within primary tumor and metastatic deposits. Mol Cancer Ther; 16(5); 948–55. ©2017 AACR.

Given the success of immunotherapy (IO), multiple IO-based options exist for advanced non-small cell lung cancer (NSCLC). Currently used biomarkers do not fully predict clinical outcomes and response assessment remains limited to radiological evaluation. Dynamic biomarkers that evaluate both tumor and host immune responses to IO are needed. We studied patients with NSCLC that received IO and chemo-IO to identify predictive and longitudinal biomarkers of clinical response using circulating tumor DNA (ctDNA) and plasma proteomic dynamics. We conducted deep targeted error-correction sequencing (TEC-Seq) of plasma cell-free DNA (cfDNA) and matched white blood cell (WBC) genomic DNA (gDNA) to identify ctDNA variants. We performed multiplexed antibody-based proximity extension assays of serial plasma samples to detect immune-related proteins. From separate training (n=31) and validation (n=29) cohorts, a total of 288 plasma cfDNA and 52 WBC gDNA specimens underwent TEC-Seq. A total of 260 variants were detected in plasma cfDNA and 78 variants in WBC gDNA. Almost a third of the plasma cfDNA variants (32%, n=61 of 188) were also found in WBC gDNA and filtered out. ctDNA variants were identified in 82% of patients (n=50). In the training cohort, longitudinal decreases in ctDNA variant levels were observed in patients with durable clinical benefit (DCB). Molecular response, defined as the loss of detectable ctDNA, was associated with longer progression-free (PFS; p=0.0004, log-rank) and overall survival (OS; p=0.017, log-rank). We incorporated on-treatment ctDNA dynamics including molecular response, recrudescence, and emergence of new variants into a logistic regression model to predict clinical benefit. This integrative model predicted DCB at a sensitivity of 84%, specificity of 76%, and with an area under the curve (AUC) of 0.90, better than baseline tumor PD-L1 expression alone (AUC 0.70, p=0.044, bootstrap method). In the validation cohort, molecular response was associated with longer PFS (p=0.00098, log-rank) and OS (p=0.0037, log-rank) and the integrative model predicted DCB at a sensitivity of 100%, specificity of 78%, and AUC of 0.89. In a subset (n=28 of 31) of the training cohort, plasma proteomics analysis revealed that increased baseline levels of IL15 and DCN were independently associated with DCB (p Citation Format: Joseph C. Murray, Karlijn Hummelink, Lamia Rhymee, Alessandro Leal, Leonardo Ferreira, Mara Lanis, James R. White, Noushin Niknafs, Kristen Marrone, Jarushka Naidoo, Benjamin Levy, Samuel Rosner, Christine Hann, Josephine Feliciano, Vincent Lam, David Ettinger, Qing K. Li, Peter Illei, Kim Monkhorst, Hatim Husain, Julie R. Brahmer, Victor Velculescu, Patrick Forde, Robert B. Scharpf, Valsamo Anagnostou. Longitudinal dynamics of circulating tumor DNA and plasma proteomics predict clinical outcomes to immunotherapy in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1668.

Purpose: There is a growing interest in using circulating tumor DNA (ctDNA) testing in patients with cancer. Experimental Design: A total of 168 patients with diverse cancers were analyzed. Patients had digital next-generation sequencing (54 cancer-related gene panel including amplifications in ERBB2, EGFR, and MET) performed on their plasma. Type of genomic alterations, potential actionability, concordance with tissue testing, and patient outcome were examined. Results: Fifty-eight percent of patients (98/168) had ≥1 ctDNA alteration(s). Of the 98 patients with alterations, 71.4% had ≥ 1 alteration potentially actionable by an FDA-approved drug. The median time interval between the tissue biopsy and the blood draw was 2.7 months for patients with ≥ 1 alteration in common compared with 14.4 months (P = 0.006) for the patients in whom no common alterations were identified in the tissue and plasma. Overall concordance rates for tissue and ctDNA were 70.3% for TP53 and EGFR, 88.1% for PIK3CA, and 93.1% for ERBB2 alterations. There was a significant correlation between the cases with ≥ 1 alteration with ctDNA ≥ 5% and shorter survival (median = 4.03 months vs. not reached at median follow-up of 6.1 months; P < 0.001). Finally, 5 of the 12 evaluable patients (42%) matched to a treatment targeting an alteration(s) detected in their ctDNA test achieved stable disease ≥ 6 months/partial remission compared with 2 of 28 patients (7.1%) for the unmatched patients, P = 0.02. Conclusions: Our initial study demonstrates that ctDNA tests provide information complementary to that in tissue biopsies and may be useful in determining prognosis and treatment. Clin Cancer Res; 22(22); 5497–505. ©2016 AACR.

9586 Background: High-dose osimertinib 160 mg QD (osi160) has activity in osi-naïve, EGFR+ NSCLC pts with CNS or leptomeningeal disease (LMD) per the BLOOM trial, but the role of dose-escalation for CNS progression (PD) and/or LMD that develops while on 80 mg QD (osi80) is unclear. We describe here our multi-institutional experience with osi160. Methods: 105 pts from 8 institutions with advanced EGFR+ NSCLC treated with osi160 were retrospectively reviewed. To assess the CNS efficacy of dose escalation for CNS PD, we focused on pts who escalated from osi80 to osi160 for CNS PD without the addition of chemo and/or RT during dose escalation (cohort A, 24 pts). We also examined osi escalation for CNS PD while receiving chemo and/or RT (cohort B, 34 pts) and those who started on osi160 for CNS PD as the initial osi dose without overlapping therapies (cohort C, 11 pts). Radiographic responses were clinically assessed via chart review of scan reports. Kaplan-Meier analysis was used for time-to-event endpoints. We defined median duration of CNS disease control (MedDurCNSCon) on osi160 as time from the start of osi160 to CNS PD or discontinuation of osi160. Results: Among the 105 pts, 69 (26M, 43F; median age 57) EGFR+ NSCLC pts (29 del19, 31 L858R, 9 other) received osi160 for CNS PD between 10/2013 and 1/2020. Median lines of therapy pre-osi was 1 (range 0-8). While all 69 pts had CNS PD at the start of osi160, 61 (90%) had isolated CNS/LMD PD, without systemic PD. In cohort A, osi160 monotherapy had a MedDurCNSCon of 3.8 mos (95% CI, 1.7 – 5.8). Cohort A pts with isolated LMD (11) had MedDurCNSCon 5.8 mos (95% CI, 1.7 – 9) while those with parenchymal mets only (11) had MedDurCNSCon of 2 mos (95% CI, 1 - 4.9). In cohort B, osi160 in combination with RT (22) and/or chemo (14), had a MedDurCNSCon of 5.1 mos (95% CI, 3.1 – 6.5). In cohort C, osi160 monotherapy had a MedDurCNSCon of 4.2 mos (95% CI, 1.6 – NA). Pts on osi160 had no severe or life-threatening side effects. Conclusions: In this real-world cohort of EGFR+ NSCLC pts with CNS and/or LMD PD on osi80, dose escalation to 160 provided modest benefit with median 3.8 mos added CNS disease control. Dose escalation appeared more effective in pts with LMD versus parenchymal disease (MedDurCNSCon of 5.8 vs 2 mos). Treatment intensification with osi escalation plus RT and/or chemo appeared to confer about 1 month additional CNS disease control (power for comparison limited). Osi naïve pts started at 160 for CNS PD derived similar benefit. While limited by small numbers and retrospective design, this study suggests we need improved strategies to optimally manage CNS PD arising on osi80.

9570 Background: Osimertinib (osi) is a 3rd generation EGFR tyrosine kinase inhibitor (TKI) approved for first line (1L) treatment of metastatic NSCLC harboring EGFR Exon 19 del and L858R (representing > 80% of EGFR activating mutations) or in NSCLC with EGFRT790M (the most common resistance mutation to 1st or 2nd generation TKI). However, it has not been well-studied in EGFR-mutant NSCLC harboring less common EGFR activating mutations such as G719X, L861Q, S768I, and exon 20 insertion (ins), among others. Methods: We conducted a multi-institution, retrospective study approved on institutional IRB protocols in a series of patients (pts.) with metastatic NSCLC treated with osi who harbored at least one atypical EGFR mutation, excluding those with concurrent L858R, Exon 19 del, or T790M. Kaplan-Meier analyses were generated with SPSS, v25 (IBM Corp., USA). Response was assessed by RECIST 1.1 in evaluable pts. Time on osi was employed as a surrogate endpoint for clinical benefit in this retrospective analysis. Results: Fifty-one NSCLC pts with uncommon EGFR mutations were identified among six US institutions. Pt characteristics: 72.5% women, median age 65 yo (44-83 yo), 82.3% ECOG PS 0-1, 43.1% never smoker, 100% lung adenocarcinoma, 58.8% Caucasian, 25.5% Asian, 3.9% Black, 2.0% Hispanic, and 9.8% Other. The most frequent mutations were L861Q (35.3%, N = 18), G719X (27.5%, N = 14), and Exon 20 ins (15.7%, N = 8). Osi was used in the 1L setting in 39.2% (N = 20). Median time on osi was 7.1 months (mo.) in the overall cohort (95% CI, 5.4 to 8.8 mo.) and 8.9 mo. (95% CI, 7.0 to 10.8 mo.) in pts receiving 1L osi. Patients harboring G719X (N = 4) and L861Q (N = 10) mutations had a median time on 1L osimertinib of 5.8 mo. and 19.3 mo., respectively. One patient’s tumor had an EGFR exon 19 ins and was on 1L osi with a partial response for 16.8 months. Two patients with Exon 20 ins were on 1L osi for 9.3 mo. and 8 mo., respectively. Conclusions: In this largest known clinically annotated dataset of patients with atypical EGFR-mutations treated with osi, activity was noted, though 1L clinical benefit on osi appears lower in this multicenter US cohort than in E19del or L858R. These results are comparable to the recently published prospective phase II trial ( Cho et al, 2019) conducted in Korea. Patients with L861Q and Exon 19 insertion appeared to benefit the most from osi in this time on treatment retrospective analysis. More detailed analysis of this cohort is planned and further prospective studies are warranted to determine clinical benefit of osi amongst diverse atypical EGFR-mutations.

Background Circulating tumor DNA (ctDNA) isolated from plasma contains genetic mutations that can be representative of those found in primary tumor tissue DNA. These samples can provide insights into tumoral heterogeneity in patients with advanced gastric cancer (AGC). Although trastuzumab has been shown to be effective in first-line therapy for patients with metastatic gastric cancer with overexpression of human epidermal growth factor receptor 2 (HER2), the mechanism of AGC resistance is incompletely understood. Methods In this prospective study, we used targeted capture sequencing to analyze 173 serial ctDNA samples from 39 AGC patients. We analyzed cancer cell fractions with PyClone to understand the clonal population structure in cancer, and monitored serial samples during therapy. Serial monitoring of ctDNA using the molecular tumor burden index (mTBI), identified progressive disease before imaging results (mean: 18 weeks). Findings We reconstructed the clonal structure of ctDNA during anti-HER2 treatment, and identified 32 expanding mutations potentially related to trastuzumab resistance. Multiple pathways activating in the same patients revealed heterogeneity in trastuzumab resistance mechanisms in AGC. In patients who received chemotherapy, mTBI was validated for the prediction of progressive disease, with a sensitivity of 94% (15/16). A higher mTBI (≥1%) in pretreatment ctDNA was also a risk factor for progression-free survival. Conclusions Analysis of ctDNA clones based on sequencing is a promising approach to clinical management, and may lead to improved therapeutic strategies for AGC patients. Fund This work was supported by grants from the National International Cooperation Grant (to J.X.; Project No. 2014DFB33160 ).

Human epidermal growth factor receptor 2 (HER2) amplification and mutations are oncogenic drivers in 2–5% of lung adenocarcinomas. HER2 exon 20 in-frame mutations may be phenotypically related to the non-smoking Asian female population and mutually exclusive of other known lung mutations and HER2 amplification. Although HER2 amplification may be an important mechanism for acquired resistance to epidermal growth factor (EGFR) tyrosine kinase inhibitors (TKIs), the prognostic and predictive significance of the amplification event appears to be different in non-small cell lung cancer (NSCLC) compared to breast and gastric cancer. Single-agent HER2-targeted antibodies and dimerization inhibitor responses have been limited, however encouraging responses have been seen with TKIs targeting Pan-HER agents and antibody drug conjugates. Based on a small trial, the National Comprehensive Cancer Network (NCCN) recommends HER2 exon 20 insertion mutants who have progressed on chemotherapy be considered for ado-trastuzumab emtansine. Further studies are needed in this population of patients. The type of HER2 alterations (mutation/amplification) needs to be precisely defined, and the most compelling data for targeted approaches currently exists in select HER2 mutation positive patients. Advances and approvals for next generation sequencing (NGS) technology have the potential to facilitate the identification of patients who may derive benefit for treatment options.

Tumor heterogeneity was associated with treatment outcome of metastatic cancers but few studies have examined whether tumor heterogeneity in circulating tumor DNA (ctDNA) can be used to predict treatment outcome. ctDNA analysis was performed in 37 HER2-positive metastatic breast cancer patients treated with pyrotinib. Patients with high tumor heterogeneity had significantly worse PFS outcomes, with a median PFS of 30.0 weeks vs. 60.0 weeks for patients with low tumor heterogeneity (hazard ratio [HR], 2.9; p = 0.02). Patients with trunk resistance mutations receiving pyrotinib monotherapy had worse outcomes (HR, 4.5; p = 0.03), with a median PFS of 7.8 weeks vs. 27.4 weeks for those with branch resistance mutations or without any resistance mutations in baseline ctDNA. Longitudinal monitoring of 21 patients during treatment showed that the molecular tumor burden index ([mTBI] a measure of the percentage of ctDNA in samples) was positively correlated with tumor size as evaluated by computed tomography (p < 0.0001, Pearson r = 0.52) and detected disease progression 8-16 weeks earlier. Our current findings suggested that ctDNA could be used to assess tumor heterogeneity and predict treatment outcomes. Furthermore, the mTBI is better for assessing therapeutic response than single gene mutations and might supplement the current therapeutic response evaluation system.

Item does not contain fulltext Cell-free DNA in the blood provides a non-invasive diagnostic avenue for patients with cancer(1). However, characteristics of the origins and molecular features of cell-free DNA are poorly understood. Here we developed an approach to evaluate fragmentation patterns of cell-free DNA across the genome, and found that profiles of healthy individuals reflected nucleosomal patterns of white blood cells, whereas patients with cancer had altered fragmentation profiles. We used this method to analyse the fragmentation profiles of 236 patients with breast, colorectal, lung, ovarian, pancreatic, gastric or bile duct cancer and 245 healthy individuals. A machine learning model that incorporated genome-wide fragmentation features had sensitivities of detection ranging from 57% to more than 99% among the seven cancer types at 98% specificity, with an overall area under the curve value of 0.94. Fragmentation profiles could be used to identify the tissue of origin of the cancers to a limited number of sites in 75% of cases. Combining our approach with mutation-based cell-free DNA analyses detected 91% of patients with cancer. The results of these analyses highlight important properties of cell-free DNA and provide a proof-of-principle approach for the screening, early detection and monitoring of human cancer.

EGFR-activating mutations are observed in approximately 15% to 20% of patients with non–small cell lung cancer. Tyrosine kinase inhibitors have provided an illustrative example of the successes in targeting oncogene addiction in cancer and the role of tumor-specific adaptations conferring therapeutic resistance. The compound osimertinib is a third-generation tyrosine kinase inhibitor, which was granted full FDA approval in March 2017 based on targeting EGFR T790M resistance. The compound has received additional FDA approval as first-line therapy with improvement in progression-free survival by suppressing the activating mutation and preventing the rise of the dominant resistance clone. Drug development has been breathtaking in this space with other third-generation compounds at various stages of development: rociletinib (CO-1686), olmutinib (HM61713), nazartinib (EGF816), naquotinib (ASP8273), mavelertinib (PF-0647775), and AC0010. However, therapeutic resistance after the administration of third-generation inhibitors is complex and not fully understood, with significant intertumoral and intratumoral heterogeneity. Repeat tissue and plasma analyses on therapy have revealed insights into multiple mechanisms of resistance, including novel second site EGFR mutations, activated bypass pathways such as MET amplification, HER2 amplification, RAS mutations, BRAF mutations, PIK3CA mutations, and novel fusion events. Strategies to understand and predict patterns of mutagenesis are still in their infancy; however, technologies to understand synthetically lethal dependencies and track cancer evolution through therapy are being explored. The expansion of combinatorial therapies is a direction forward targeting minimal residual disease and bypass pathways early based on projected resistance.

Brain metastases are common in patients with non-small-cell lung cancer (NSCLC). Because of associated poor prognosis and limited specific treatment options, there is a real need for the development of medical therapies and strategies for affected patients. Novel compounds for epidermal growth factor receptor-dependent and anaplastic lymphoma kinase-dependent lung cancer have demonstrated blood-brain barrier permeability and have led to important improvements in central nervous system outcomes. Studies of targeted therapies for oncogene-driven tumors and of immunotherapies in patients with brain metastases have shown promise and, allied with novel radiation techniques, are driving a rapid evolution in treatment and prognosis for NSCLC brain metastases.

Purpose Dabrafenib and trametinib are approved for the management of advanced non–small-cell lung cancers (NSCLCs) that harbor BRAF V600E mutations. Small series and pan-cancer analyses have identified non-V600 alterations as therapeutic targets. We sought to examine a large genomic data set to comprehensively characterize non-V600 B RAF alterations in lung cancer. Patients and Methods A total of 23,396 patients with lung cancer provided data to assay with comprehensive genomic profiling. Data were reviewed for predicted pathogenic BRAF base substitutions, short insertions and deletions, copy number changes, and rearrangements. Results Adenocarcinomas represented 65% of the occurrences; NSCLC not otherwise specified (NOS), 15%; squamous cell carcinoma, 12%; and small-cell lung carcinoma, 5%. BRAF was altered in 4.5% (1,048 of 23,396) of all tumors; 37.4% (n = 397) were BRAF V600E, 38% were BRAF non-V600E activating mutations, and 18% were BRAF inactivating. Rearrangements were observed at a frequency of 4.3% and consisted of N-terminal deletions (NTDs; 0.75%), kinase domain duplications (KDDs; 0.75%), and BRAF fusions (2.8%). The fusions involved three recurrent fusion partners: ARMC10, DOCK4, and TRIM24. BRAF V600E was associated with co-occurrence of SETD2 alterations, but other BRAF alterations were not and were instead associated with CDKN2A, TP53, and STK11 alterations ( P < .05). Potential mechanisms of acquired resistance to BRAF V600E inhibition are demonstrated. Conclusion This series characterized the frequent occurrence (4.4%) of BRAF alterations in lung cancers. Recurrent BRAF alterations in NSCLC adenocarcinoma are comparable to the frequency of other NSCLC oncogenic drivers, such as ALK, and exceed that of ROS1 or RET. This work supports a broad profiling approach in lung cancers and suggests that non-V600E BR AF alterations represent a subgroup of lung cancers in which targeted therapy should be considered.

Desmoplastic small round blue cell tumors (DSRCTs) originate from a cell with multilineage potential. A molecular hallmark of DSRCT is the EWS-WT1 reciprocal translocation. Ewing sarcoma and DSRCT are treated similarly due to similar oncogene activation pathways, and DSRCT has been represented in very limited numbers in sarcoma studies. Despite aggressive therapy, median survival ranges from 17 to 25 months, and 5-year survival rates remain around 15%, with higher survival reported among those undergoing removal of at least 90% of tumor in the absence of extraperitoneal metastasis. Almost 100% of these tumors contain t(11;22) (p13;q12) translocation, and it is likely that EWS-WT1 functions as a transcription factor possibly through WT1 targets. While there is no standard protocol for this aggressive disease, treatment usually includes the neoadjuvant HD P6 regimen (high-dose cyclophosphamide, doxorubicin, and vincristine (HD-CAV) alternating with ifosfamide and etoposide (IE) chemotherapy combined with aggressively attempted R0 resection). We aimed to review the molecular characteristics of DSRCTs to explore therapeutic opportunities for this extremely rare and aggressive cancer type.