2023 World Conference on Lung Cancer (Posters)-EP13.05. Early ctDNA Changes and Clinical Outcomes in Extensive Stage Small Cell Lung Cancer Patients on Nivolumab and Temozolomide

EP13.05. Early ctDNA Changes and Clinical Outcomes in Extensive Stage Small Cell Lung Cancer Patients on Nivolumab and Temozolomide - PDF(Abstract)

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This study aimed to explore the association between changes in circulating tumor DNA (ctDNA) and clinical outcomes in patients with relapsed extensive-stage small cell lung cancer (ES-SCLC) who were treated with nivolumab and temozolomide. The phase 2 trial included 27 patients, and plasma samples were collected before cycles 1 and 2 of treatment. Genomic alterations were assessed using Guardant360, and the molecular response to treatment was evaluated by analyzing the ratio of mean variant allele fraction (meanVAF) from pre-treatment to on-treatment samples. Survival outcomes were estimated using the Kaplan-Meier method and compared between patients with ctDNA increase and decrease.<br /><br />The results showed that the median progression-free survival (mPFS) for all treated patients was 2.4 months, and the median overall survival (mOS) was 6.3 months. Among the 19 patients with available baseline ctDNA samples, the most common alterations were TP53 (100%), RB1 (89%), BRCA2 (58%), ARID1A (47%), and CHK2 (47%). Of the 15 patients with paired baseline and cycle 2 ctDNA samples, 10 (66.7%) showed a decrease in ctDNA, which was associated with improved mPFS (3.3 vs. 1.9 months). However, there was no significant association with mOS. The mean ctDNA reduction was -61.5% among the patients who achieved ctDNA reduction from the baseline.<br /><br />The study concluded that an early decrease in ctDNA following nivolumab and temozolomide treatment was associated with progression-free survival in heavily pretreated patients with ES-SCLC. These findings support the use of serial ctDNA monitoring in clinical trials for small cell lung cancer. However, the study had limitations, including laboratory limitations due to the COVID-19 pandemic and a small number of patients, which limited the interpretation of overall survival.

Asset Subtitle

Jinesh Gheeya

Meta Tag

Speaker Jinesh Gheeya

Topic SCLC & Neuroendocrine Tumors: NETs

Keywords

circulating tumor DNA

ctDNA

clinical outcomes

relapsed extensive-stage small cell lung cancer

nivolumab

temozolomide

progression-free survival

overall survival

genomic alterations

serial ctDNA monitoring