ctDNA-based minimal residual disease detection in lung cancer patients treated with curative intended chemoradiotherapy using a clinically transferable approach.

BACKGROUND: Reliable biomarkers are needed to identify tumor recurrence of non-small cell lung cancer (NSCLC) patients after chemoradiotherapy (CRT) with curative intent. This could improve consolidation therapy of progressing patients. However, the approach of existing studies has limited transferability to the clinic. MATERIALS AND METHODS: A retrospective analysis of 135 plasma samples from 56 inoperable NSCLC patients who received CRT with curative intent was performed. Plasma samples collected at baseline, at the first check-up (average 1.6 months post-RT), and at the second check-up (average 4.5 months post-RT) were analyzed by deep sequencing with a commercially available cancer personalized profiling strategy (CAPP-Seq) using a tumor-agnostic approach. RESULTS: Detection of circulating tumor DNA (ctDNA) at 4.5 months after therapy was significantly associated with higher odds of tumor recurrence (OR: 5.4 (CI: 1.1-31), Fisher's exact test: p-value = 0.022), and shorter recurrence-free survival (RFS) (HR: 4.1 (CI: 1.7-10); log-rank test: p-value = 9e-04). In contrast, detection of ctDNA at 1.6 months after therapy was not associated with higher odds of tumor recurrence (OR: 2.7 (CI: 0.67-12), Fisher's exact test: p-value = 0.13) or shorter RFS (HR: 1.5 (CI: 0.67-3.3); log-rank test: p-value = 0.32). CONCLUSION: This study demonstrates that the detection of ctDNA can be used to identify minimal residual disease 4.5 months after CRT in NSCLC patients using a commercially available kit and a tumor-agnostic approach. Furthermore, the time point of collecting the plasma sample after CRT has decisive importance for the prognostic value of ctDNA. MICRO ABSTRACT: This study analysed 135 plasma samples from 56 NSCLC patients treated with curative intent chemoradiotherapy using a tumor-agnostic approach. Detecting ctDNA at 4.5 months post-treatment was linked to higher recurrence odds, indicating ctDNA's potential as a biomarker for identifying residual disease after treatment with curative intent. Importantly, the study emphasizes the importance of timing for accurate ctDNA analysis results.

Plasma Immune Proteins and Circulating Tumor DNA Predict the Clinical Outcome for Non-Small-Cell Lung Cancer Treated with an Immune Checkpoint Inhibitor.

Immunotherapy has altered the therapeutic landscape for patients with non-small-cell lung cancer (NSCLC). The immune checkpoint inhibitor pembrolizumab targets the PD-1/PD-L1 signaling axis and produces durable clinical responses, but reliable biomarkers are lacking. Using 115 plasma samples from 42 pembrolizumab-treated patients with NSCLC, we were able to identify predictive biomarkers. In the plasma samples, we quantified the level of 92 proteins using the Olink proximity extension assay and circulating tumor DNA (ctDNA) using targeted next-generation sequencing. Patients with an above-median progression-free survival (PFS) had significantly higher expressions of Fas ligand (FASLG) and inducible T-cell co-stimulator ligand (ICOSLG) at baseline than patients with a PFS below the median. A Kaplan-Meier analysis demonstrated that high levels of FASLG and ICOSLG were predictive of longer PFS and overall survival (OS) (PFS: 10.83 vs. 4.49 months, OS: 27.13 vs. 18.0 months). Furthermore, we identified a subgroup with high expressions of FASLG and ICOSLG who also had no detectable ctDNA mutations after treatment initiation. This subgroup had significantly longer PFS and OS rates compared to the rest of the patients (PFS: 25.71 vs. 4.52 months, OS: 34.62 vs. 18.0 months). These findings suggest that the expressions of FASLG and ICOSLG at baseline and the absence of ctDNA mutations after the start of treatment have the potential to predict clinical outcomes.

Blood tumor mutational burden and dynamic changes in circulating tumor DNA predict response to pembrolizumab treatment in advanced non-small cell lung cancer.

Background: The use of immunotherapy targeting the programmed cell death protein-1 (PD-1) and its ligand (PD-L1) has provided new hope for patients with non-small cell lung cancer (NSCLC). However, good biomarkers are needed to identify which patients will benefit from the treatment. In this study, we investigated if circulating tumor DNA (ctDNA) could predict response to pembrolizumab. Methods: Plasma samples from patients with NSCLC treated with pembrolizumab were collected immediately before and after one or two cycles of treatment. ctDNA was isolated and analyzed using targeted next-generation sequencing with a lung cancer gene panel. Results: Mutations were detected in ctDNA in 83.93% of patients before treatment initiation. High blood tumor mutational burden (bTMB), measured as the number of different mutations per Mb panel, correlated to longer progression-free survival (PFS) (10.45 vs. 2.30 months) and overall survival (OS) (21.80 vs. 12.20 months), whereas no predictive value was found in the number of mutant molecules per mL of plasma. The absence of mutations just after treatment initiation correlated with improved PFS (20.25 vs. 4.18 months) and OS (28.93 vs. 15.33 months). High bTMB before treatment was associated with a decreasing ctDNA level after treatment initiation. Importantly, a subgroup of patients experienced an increase in the ctDNA level after treatment initiation, and this correlated with inferior PFS (2.19 vs. 11.21 months) and OS (7.76 vs. 24.20 months). All patients in the subgroup with increased ctDNA level progressed within 10 months. Conclusions: Monitoring of ctDNA contains vital information about response to therapy, where the bTMB and the dynamics in the initial part of treatment are particularly important for response. Increasing ctDNA levels after treatment initiation are significantly correlated with inferior survival.

Osimertinib in non-small cell lung cancer with uncommon EGFR-mutations: a post-hoc subgroup analysis with pooled data from two phase II clinical trials.

Background: Osimertinib is standard of care for EGFR-mutated non-small cell lung cancer (NSCLC) patients. The efficacy of the drug in patients with mutations other than the common deletion in exon 19 and L858R in exon 21 is largely unknown. Methods: We identified patients with uncommon EGFR-mutations from two prospective clinical phase II, single-arm studies for previously treated patients and untreated patients, respectively, and pooled data for this analysis. All patients received treatment with osimertinib 80 mg daily until radiological progression or death. The primary endpoint of both trials was objective response rate (ORR), with progression-free survival (PFS), overall survival (OS) and intracranial efficacy as key secondary endpoints. Circulating tumour DNA (ctDNA) was analysed before and two weeks after treatment initiation in the first line cohort. Results: Of 299 enrolled patients in the two trials, 21 patients with uncommon mutations were identified; 12 patients had a single mutation (G719X or L861Q), one patient had L861Q and an exon 20 insertion, and 8 patients had compound mutations with G719X and either L861Q or S768I. Three of the 10 pretreated patients had the T790M resistance mutation. ORR was 47.6% and disease control rate (DCR) 85.7%. The median duration of response (DoR) was 7.9 months. Among 11 patients treated with osimertinib in first line, ORR was 63.6% vs. 30.0% of 10 previously treated patients. The median PFS was 5.5 months in both groups. Patients with G719X-compound mutations had a higher response rate (62.5% vs. 38.5%), a longer median PFS (13.7 vs. 3.5 months) and median OS (29.3 vs. 7.5 months) than patients with other mutations. Most first line treated patients (81.8%) displayed a reduction in ctDNA after two weeks of treatment. Conclusions: Osimertinib demonstrates activity in patients with uncommon EGFR-mutations, and especially for G719X-compound mutations.