Endocrine-resistant, hormone receptor-positive, and HER2-negative (HR+/HER2-) metastatic breast cancer (mBC) is largely governed by acquired mutations in the estrogen receptor, which promote ligand-independent activation, and by truncal alterations in the PI3K signaling pathway, with a broader range of gene alterations occurring with less prevalence. Circulating tumor DNA (ctDNA)-based technologies are progressively permeating the clinical setting. However, their utility for serial monitoring has been hindered by their significant costs, inter-technique variability, and real-world patient heterogeneity. We interrogated a longitudinal collection of 180 plasma samples from 75 HR+/HER2- mBC patients who progressed or relapsed after exposure to aromatase inhibitors and were subsequently treated with endocrine therapy (ET) by means of highly sensitive and affordable digital PCR and SafeSEQ sequencing. Baseline PIK3CA and TP53 mutations were prognostic of a shorter progression-free survival in our population. Mutant PIK3CA was prognostic in the subset of patients receiving fulvestrant monotherapy after progression to a CDK4/6 inhibitor (CDK4/6i)-containing regimen, and its suppression was predictive in a case of long-term benefit with alpelisib. Mutant ESR1 was prognostic in patients who did not receive concurrent CDK4/6i, an impact influenced by the variant allele frequency, and its early suppression was strongly predictive of efficacy and associated with long-term benefit in the whole cohort. Mutations in ESR1, TP53, and KRAS emerged as putative drivers of acquired resistance. These findings collectively contribute to the characterization of longitudinal ctDNA in real-world cases of HR+/HER2- mBC previously exposed to aromatase inhibitors and support ongoing studies either targeting actionable alterations or leveraging the ultra-sensitive tracking of ctDNA.

Molecular testing using blood-based liquid biopsy approaches has not been widely investigated in patients with glioma. A prospective single-center study enrolled patients with gliomas ranging from grade II to IV. Peripheral blood (PB) was drawn at different timepoints for circulating tumour DNA (ctDNA) monitoring. Next-generation sequencing (NGS) was used for the study of isocitrate dehydrogenase 1 (IDH1) mutations in the primary tumor. Beads, Emulsion, Amplification and Magnetics (BEAMing) was used for the study of IDH1 mutations in plasma and correlated with the NGS results in the tumor. Between February 2017 and July 2018, ten patients were enrolled, six with IDH1-mutant and four with IDH1 wild-type gliomas. Among the six IDH-mutant gliomas, three had the same IDH1 mutation detected in plasma (50%), and the IDH1-positive ctDNA result was obtained in patients either at diagnosis (no treatment) or during progressive disease. While the false-negative rate reached 86% (18/21), 15 out of the 18 (83%) plasma-negative results were from PB collected from the six IDH-mutant patients at times at which there was no accompanying evidence of tumor progression, as assessed by MRI. There were no false-positive cases in plasma collected from patients with IDH1 wild-type tumors. BEAMing detected IDH1 mutations in the plasma of patients with gliomas, with a modest clinical sensitivity (true positivity rate) but with 100% clinical specificity, with complete agreement between the mutant loci detected in tumor and plasma. Larger prospective studies should be conducted to expand on these findings, and further explore the clearance of mutations in PB from IDH1-positive patients in response to therapy.

BLOODPAC is a public‐private consortium that develops best practices, coordinates clinical and translational research, and manages the BLOODPAC Data Commons to broadly support the liquid biopsy community and accelerate regulatory review to aid patient accessibility. BLOODPAC previously recommended 11 preanalytical minimal technical data elements (MTDEs) for BLOODPAC‐sponsored studies and data submitted to BLOODPAC Data Commons. The current landscape analysis evaluates the overlap of the BLOODPAC MTDEs with current best practices, guidelines, and standards documents related to clinical and research liquid biopsy applications. Our findings indicate an existing high degree of concordance among these documents. Where differences exist, the BLOODPAC preanalytical MTDEs can be considered a minimal practicable set for organizations to utilize. These MTDEs were developed following extensive examination of best practices and iterative conversations with the U.S. FDA. BLOODPAC recommends the use of these MTDEs in submissions to data commons and to support liquid biopsy clinical trials and research globally.

Purpose: Human papillomavirus–associated (HPV+) oropharyngeal carcinoma is associated with excellent survival, yet treatment drives substantial toxicity. Improved biomarkers are needed to select patients for de-escalated treatment. Circulating tumor HPV DNA (ctHPV-DNA) represents a promising noninvasive biomarker to gauge treatment response and surveil for disease recurrence. Patients and Methods: A prospective biomarker clinical trial of response-stratified de-escalation was conducted. Eligible patients with non-metastatic HPV+ oropharyngeal carcinoma received neoadjuvant chemotherapy, followed by risk/response-stratified de-escalation with transoral robotic surgery, de-escalated radiation with or without chemotherapy to 50 Gy, or standard chemoradiation to 70 Gy. Deep response (≥50% tumor shrinkage per RECIST v1.1) qualified patients for de-escalation. ctHPV-DNA was measured using HPV-SEQ in plasma at baseline, during neoadjuvant chemotherapy, radiation, and following treatment. The primary endpoint was the correlation of ctHPV-DNA kinetics and radiographic response. Results: Forty-six eligible patients were enrolled, and 488 ctHPV-DNA samples were analyzed (median 11 per patient). The median follow-up was 30 months, and five recurrences were observed (10.9%). Baseline ctHPV-DNA was detected in 95% of evaluable patients. Rapid early ctHPV-DNA clearance after one cycle of neoadjuvant therapy (≥95% reduction) predicted radiographic deep response (P = 0.04). Detection of ctHPV-DNA 3 months or later after treatment was associated with worse progression-free and overall survival (P < 0.001). Sensitivity, specificity, and positive and negative predictive values of longitudinal ctHPV-DNA were 100%. The longest lead time from positive ctHPV-DNA to detection of recurrent disease was 25 months. Conclusions: Rapid early clearance of ctHPV-DNA during neoadjuvant therapy demonstrates utility in predicting response to treatment. Detectable ctHPV-DNA following treatment is predictive of both disease recurrence and worse survival.

Background: Various methods have been employed to detect plasma EGFR mutations in patients with non-small cell lung cancer patients (NSCLC). Therefore, we evaluated the performance of digital PCR and next generation sequencing (NGS) to detect the p.T790M EGFR mutation in prospectively collected patient samples. Paired plasma samples from patients (CIRCAN cohort) that progressed on first-line EGFR TKI therapy were compared using two platforms: OncoBEAM^TM-EGFR (Sysmex Inostics) and NGS (Illumina), utilizing the 56G oncology panel (Swift Biosciences).