From the beginning to resistance: Study of plasma monitoring and resistance mechanisms in a cohort of patients treated with osimertinib for advanced T790M-positive NSCLC.
Lung Cancer
; 131: 78-85, 2019 05.
Article
em En
| MEDLINE
| ID: mdl-31027702
ABSTRACT
INTRODUCTION:
Analysis of circulating tumor DNA (ctDNA) for the identification of T790M mutation in advanced EGFR-mutated NSCLC patients can replace tissue re-biopsy for resistance characterization and, being non-invasive, may be applied for disease monitoring. We analysed ctDNA during osimertinib treatment to correlate mutational levels with clinical outcome and to predict pattern of resistance. MATERIALS ANDMETHODS:
Forty patients with advanced NSCLC receiving osimertinib for T790M + disease after previous EGFR-TKI were enrolled in a pilot study to collect plasma at baseline and every 12 weeks until progression. Molecular analysis of ctDNA was performed by ddPCR and Therascreen®. When feasible at progression, tissue re-biopsy and NGS analysis were performed.RESULTS:
Thirty-eight patients had baseline plasma samples suitable for molecular analysis. Patients with low levels of the EGFR activating mutation in ctDNA [< 2200 copies/mL or allele frequency (AF) < 6.1%] showed better progression-free survival (17.8 or 17.8 months vs. 4.3 or 2.7, p = 0.022 or p = 0.018, respectively) and overall survival (23.6 or 23.6 vs. 7.7 or 7.3, p = 0.016 or p = 0.013, respectively) than patients with high levels (≥ 2200 copies/mL or AF ≥ 6.1%). Patients with detectable EGFR mutations in plasma (shedders) presented worse outcome than negative subjects (non-shedders). Low levels of T790M, higher T790M/activating mutation ratio and complete clearance after 2 months were associated with a trend towards better outcome. Tissue re-biopsy at resistance showed 3 patients with EGFR C797S, 1 with MET amplification, 1 with MYC amplification, 1 with PTEN loss, 3 with SCLC transformation.CONCLUSIONS:
The mutational analysis performed on plasma plays a significant role in prognostic stratification, especially for the EGFR activating mutation, since patients with absence or low levels of mutations presented a better outcome to osimertinib. At progression, tissue re-biopsy remains a crucial issue for the identification of resistance mechanisms.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Diagnostic_studies
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Etiology_studies
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Incidence_studies
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Observational_studies
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Prognostic_studies
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Risk_factors_studies
Limite:
Aged
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Aged80
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article