Circulating Tumor DNA in Advanced EGFRex20+ NSCLC: Concordance with Tissue Biopsy, Monitoring of Response, and Resistance to High-Dose Osimertinib
Bibliographic record
Abstract
BACKGROUND: High-dose osimertinib shows modest anti-tumor activity and acceptable toxicity in patients with advanced non-small cell lung cancer (NSCLC) harboring an epidermal growth factor receptor exon 20 mutation (EGFRex20+). Plasma-derived circulating tumor DNA (ctDNA) is promising in monitoring responses and detecting resistance mechanisms to therapy. OBJECTIVE: We aimed to assess the concordance between variants detected in ctDNA to those found in corresponding tissue samples at baseline and progression, to analyze alterations in mutant ctDNA levels of EGFRex20+ variants as predictors of therapy response, and to identify resistance mechanisms to high-dose osimertinib as well as examine changes in mutant ctDNA levels of EGFRex20+ variants. PATIENTS AND METHODS: Twenty-five patients with EGFRex20+ NSCLC received double dose (160 mg) osimertinib daily. Blood plasma was collected at baseline, 6 weeks after therapy start (T6), and at progression. ctDNA analysis was performed using the NGS Guardant360 CDx panel. The molecular profile at progression was compared with baseline/T6, and changes in ctDNA levels of the EGFRex20+ variants were linked to response or resistance. RESULTS: Collected ctDNA samples were analyzed retrospectively. Baseline ctDNA showed somatic alterations in 19/20 patients (95%) and the corresponding tumor biopsy NGS EGFRex20+ variant in 65%. Among 14 patients with profiling at all timepoints, there was no significant correlation between changes in mutant ctDNA levels and osimertinib response. At T6, nine patients showed decreased EGFRex20+ levels, with eight also showing tumor shrinkage. At disease progression, 9/14 (64%) patients had increased EGFRex20+ levels, correlating with tumor growth. Variants potentially associated with resistance were found in 11/18 patients (61%): single nucleotide variants (SNV, n = 14), insertions (n = 2), and gene fusions (n = 1). Mutations previously related to osimertinib resistance were found, including EGFR p.C797S (n = 1). CONCLUSIONS: ctDNA analysis tracks variant dynamics and can identify resistance mechanisms in patients with EGFRex20+ NSCLC treated with high-dose osimertinib, offering valuable new insights.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".