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PURPOSE Immune checkpoint inhibitors (ICIs) are increasingly being used in non–small-cell lung cancer (NSCLC), yet biomarkers predicting their benefit are lacking. We evaluated if on-treatment changes of circulating tumor DNA (ctDNA) from ICI start (t0) to after two cycles (t1) assessed with a commercial panel could identify patients with NSCLC who would benefit from ICI. PATIENTS AND METHODS The molecular ctDNA response was evaluated as a predictor of radiographic tumor response and long-term survival benefit of ICI. To maximize the yield of ctDNA detection, de novo mutation calling was performed. Furthermore, the impact of clonal hematopoiesis (CH)–related variants as a source of biologic noise was investigated. RESULTS After correction for CH-related variants, which were detected in 75 patients (44.9%), ctDNA was detected in 152 of 167 (91.0%) patients. We observed only a fair agreement of the molecular and radiographic response, which was even more impaired by the inclusion of CH-related variants. After exclusion of those, a ≥ 50% molecular response improved progression-free survival (10 v 2 months; hazard ratio [HR], 0.55; 95% CI, 0.39 to 0.77; P = .0011) and overall survival (18.4 v 5.9 months; HR, 0.44; 95% CI, 0.31 to 0.62; P < .0001) compared with patients not achieving this end point. After adjusting for clinical variables, ctDNA response and STK11/ KEAP1 mutations (HR, 2.08; 95% CI, 1.4 to 3.0; P < .001) remained independent predictors for overall survival, irrespective of programmed death ligand-1 expression. A landmark survival analysis at 2 months (n = 129) provided similar results. CONCLUSION On-treatment changes of ctDNA in plasma reveal predictive information for long-term clinical benefit in ICI-treated patients with NSCLC. A broader NSCLC patient coverage through de novo mutation calling and the use of a variant call set excluding CH-related variants improved the classification of molecular responders, but had no significant impact on survival.

Background: Molecular diagnosis has become an established tool in the characterisation of adult soft-tissue sarcomas (STS). FoundationOne® Heme analyses somatic gene alterations in sarcomas via DNA and RNA-hotspot sequencing of tumour-associated genes. Methods: We evaluated FoundationOne® Heme testing in 81 localised STS including 35 translocation-associated and 46 complex-karyotyped cases from a single institution. Results: Although FoundationOne® Heme achieved broad patient coverage and identified at least five genetic alterations in each sample, the sensitivity for fusion detection was rather low, at 42.4%. Nevertheless, potential targets for STS treatment were detected using the FoundationOne® Heme assay: complex-karyotyped sarcomas frequently displayed copy-number alterations of common tumour-suppressor genes, particularly deletions in TP53, NF1, ATRX, and CDKN2A. A subset of myxofibrosarcomas (MFS) was amplified for HGF ( n = 3) and MET ( n = 1). PIK3CA was mutated in 7/15 cases of myxoid liposarcoma (MLS; 46.7%). Epigenetic regulators (e.g. MLL2 and MLL3) were frequently mutated. Conclusions: In summary, FoundationOne® Heme detected a broad range of genetic alterations and potential therapeutic targets in STS (e.g. HGF/MET in a subset of MFS, or PIK3CA in MLS). The assay’s sensitivity for fusion detection was low in our sample and needs to be re-evaluated in a larger cohort.

We addressed a significant unknown feature of circulating tumor DNA (ctDNA), i.e., how ctDNA levels change during chemotherapy, by serially monitoring ctDNA in patients with colorectal cancer during the 48-h application of FOLFOX. Surprisingly, we did not observe a spike in ctDNA as a sign of a responsive tumor, but instead ctDNA levels initially decreased and remained low in patients with stable disease or partial response. Our observations reveal further insights into cell destruction during chemotherapy with important implications for the management of patients.

Novel androgen receptor (AR) signaling inhibitors have improved the treatment of castration-resistant prostate cancer (CRPC). Nonetheless, the effect of these drugs is often time-limited and eventually most patients become resistant due to various AR alterations. Although liquid biopsy approaches are powerful tools for early detection of such therapy resistances, most assays investigate only a single resistance mechanism. In combination with the typically low abundance of circulating biomarkers, liquid biopsy assays are therefore informative only in a subset of patients. In this pilot study, we aimed to increase overall sensitivity for tumor-related information by combining three liquid biopsy approaches into a multi-analyte approach. In a cohort of 19 CRPC patients, we (1) enumerated and characterized circulating tumor cells (CTCs) by mRNA-based in situ padlock probe analysis, (2) used RT-qPCR to detect cancer-associated transcripts (e.g., AR and AR-splice variant 7) in lysed whole blood, and (3) conducted shallow whole-genome plasma sequencing to detect AR amplification. Although 44&ndash, 53% of patient samples were informative for each assay, a combination of all three approaches led to improved diagnostic sensitivity, providing tumor-related information in 89% of patients. Additionally, distinct resistance mechanisms co-occurred in two patients, further reinforcing the implementation of multi-analyte liquid biopsy approaches.

BackgroundCell-free tumor-derived DNA (ctDNA) allows non-invasive monitoring of cancers, but its utility in renal cell cancer (RCC) has not been established.MethodsHere, a combination of untargeted and targeted sequencing methods, applied to two independent cohorts of patients (n = 91) with various renal tumor subtypes, were used to determine ctDNA content in plasma and urine.ResultsOur data revealed lower plasma ctDNA levels in RCC relative to other cancers of similar size and stage, with untargeted detection in 27.5% of patients from both cohorts. A sensitive personalized approach, applied to plasma and urine from select patients (n = 22) improved detection to ~ 50%, including in patients with early-stage disease and even benign lesions. Detection in plasma, but not urine, was more frequent amongst patients with larger tumors and in those patients with venous tumor thrombus.With data from one extensively characterized patient, we observed that plasma and, for the first time, urine ctDNA may better represent tumor heterogeneity than a single tissue biopsy. Furthermore, in a subset of patients (n = 16), longitudinal sampling revealed that ctDNA can track disease course and may pre-empt radiological identification of minimal residual disease or disease progression on systemic therapy. Additional datasets will be required to validate these findings.ConclusionsThese data highlight RCC as a ctDNA-low malignancy. The biological reasons for this are yet to be determined. Nonetheless, our findings indicate potential clinical utility in the management of patients with renal tumors, provided improvement in isolation and detection approaches.

Response evaluation of cancer therapeutics relies on the assessment of the change in tumor burden, which is performed in accordance with defined criteria every 8-12 weeks. However, predictive factors for response are not available for the majority of patients with advanced stage colorectal cancer. Here we show that measurement of circulating tumor DNA (ctDNA) levels during one of the most commonly administered drug regimens, i.e. FOLFOX, allows an early, real-time assessment of treatment response. During the 48-hour FOLFOX application, we serially assessed plasma DNA and observed that ctDNA levels initially decreased during the first 23 hours. In patients with stable disease or partial response, ctDNA levels remained low, whereas in patients with progressive disease, ctDNA levels increased at the end of the treatment cycle, predicting clinical and radiologic response correctly. Hence, ctDNA monitoring during treatment may contribute to an early outcome prediction with significant implications for the management of patients.

Cell-free tumour-derived DNA (ctDNA) allows non-invasive monitoring of cancers but its utility in renal cell cancer (RCC) has not been established. Here, untargeted and targeted sequencing methods, applied to two independent cohorts of renal tumour patients (n=90), were used to determine ctDNA content in plasma and urine. Our data revealed lower plasma ctDNA levels in RCC relative to other cancers, with untargeted detection of ∼33%. A sensitive personalised approach, applied to plasma and urine from select patients improved detection to ∼50%, including in patients with early-stage and even benign lesions.A machine-learning based model predicted detection, potentially offering a means of triaging samples for personalised analysis. In addition, with limited data we observed that plasma, and for the first time, urine ctDNA may better represent tumour heterogeneity than tissue biopsy. Furthermore, longitudinal sampling of >200 plasma samples revealed that ctDNA can track disease course. Additional datasets will be required to validate these findings.Overall, our data highlight RCC as a ctDNA-low malignancy, but indicate potential clinical utility provided improvement in detection approaches.One sentence summaryComplementary sequencing methods show that cell-free tumour DNA levels are low in renal cancer though, via various strategies, may still be informative.

Background: In recent years, various efforts have been made to identify biomarkers in metastatic colorectal cancer patients (mCRC), all with the goal of improving patients' outcomes, including maximizing therapeutic response and minimizing exposure to ineffective treatments. Nevertheless, there is still no valid biomarker for the early assessment of therapeutic efficacy in the patient management strategy. To address this issue, we aimed to describe the predictive value of circulating tumor DNA (ctDNA) on the efficacy of FOLFOX treatment in mCRC patients. Patients and methods: A total of 11 patients with mCRC receiving FOLFOX therapy were included in this study. During the 48-hour FOLFOX cycle, we performed serial liquid biopsy-based ctDNA analysis before treatment start (T1) and at eight further time points (T2-T9). Among the 11 patients tested, all patients had detectable variants identified by either tumor tissue genotyping or baseline sample ctDNA sequencing for longitudinal analysis. We assessed genome-wide somatic copy number alterations (SCNAs) and highly sensitive sequencing approaches were utilized to monitor changes in the ctDNA mutant allele frequencies (mAFs) between baseline and on-treatment samples. Results: We were able to clearly assess different mAF patterns across patients with either stable disease, partial response or progressive disease. However, we invariably observed an early and deep ctDNA mAF decrease in all patients, as comparing the baseline (T1) mAF levels with the mAFs at all time points revealed that the most significant ctDNA drop was 23 hours after treatment start, i.e. at time point T5 (p Conclusion: Our observations clearly demonstrated for the first time that ctDNA dynamics allow real-time, individualized evaluation of treatment response using two early time points, i.e. at T5 and T9. Therefore, our data suggest that sequential ctDNA analysis can contribute to an improved patient treatment strategy. Nevertheless, further studies are clearly required to validate this promising early on-treatment indicator of therapeutic efficacy for CRC patients. Citation Format: Tina Moser, Julie Waldispuehl-Geigl, Jelena Belic, Samantha Perakis, Sabrina Weber, Qing Zhou, Heinz Sill, Sigurd Lax, Karl Kashofer, Gerald Hoefler, Helmut Schoellnast, Thomas Bauernhofer, Ellen Heitzer, Jochen B. Geigl, Michael R. Speicher. Early circulating tumor DNA dynamics as a real-time predictor of FOLFOX efficacy in advanced colorectal cancer patients [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 4295.